WorldWideScience

Sample records for nanorods efficiently contributed

  1. Annealing effects of ZnO nanorods on dye-sensitized solar cell efficiency

    Chung, Jooyoung; Lee, Juneyoung [Department of Chemical and Biomolecular Engineering, Yonsei University, 134 Shinchon-dong, Seodaemoon-gu, Seoul 120-749 (Korea, Republic of); Lim, Sangwoo, E-mail: swlim@yonsei.ac.k [Department of Chemical and Biomolecular Engineering, Yonsei University, 134 Shinchon-dong, Seodaemoon-gu, Seoul 120-749 (Korea, Republic of)

    2010-06-01

    Dye-sensitized solar cells (DSSCs) were fabricated using ZnO nanorod arrays vertically grown on fluorine-doped tin oxide (FTO) glass using a low-temperature hydrothermal method. When the ZnO seed layer was annealed, greater DSSC efficiency was obtained. This may be attributed to the improvement of adhesion between the FTO and the seed layer and the corresponding effective growth of the ZnO nanorods. The DSSCs fabricated using ZnO nanorods which underwent annealing were more efficient than those that did not undergo annealing. The ZnO nanorods which were annealed in N{sub 2}/H{sub 2} or O{sub 2} had increased dye loadings due to higher OH concentrations on the hydrophilic surface, which contributed to the improved DSSC efficiency. The fill factor increased after the annealing of the ZnO nanorods, potentially due to the improved crystallinity of the ZnO nanorods. In this study, annealing of both the seed layer and the ZnO nanorods resulted in the greatest DSSC efficiency.

  2. Improved Power Conversion Efficiency of Inverted Organic Solar Cells by Incorporating Au Nanorods into Active Layer.

    He, Yeyuan; Liu, Chunyu; Li, Jinfeng; Zhang, Xinyuan; Li, Zhiqi; Shen, Liang; Guo, Wenbin; Ruan, Shengping

    2015-07-29

    This Research Article describes a cooperative plasmonic effect on improving the performance of organic solar cells. When Au nanorods(NRs) are incorporated into the active layers, the designed project shows superior enhanced light absorption behavior comparing with control devices, which leads to the realization of organic solar cell with power conversion efficiency of 6.83%, accounting for 18.9% improvement. Further investigations unravel the influence of plasmonic nanostructures on light trapping, exciton generation, dissociation, and charge recombination and transport inside the thin films devices. Moreover, the introduction of high-conductivity Au NRs improves electrical conductivity of the whole device, which contributes to the enhanced fill factor.

  3. Synthesis of TiO2 nanorod-decorated graphene sheets and their highly efficient photocatalytic activities under visible-light irradiation

    Lee, Eunwoo; Hong, Jin-Yong; Kang, Haeyoung; Jang, Jyongsik

    2012-01-01

    Highlights: ► TiO 2 nanorods were successfully decorated on the surface of graphene sheets. ► Population of TiO 2 nanorods can be controlled by changing experimental conditions. ► TiO 2 nanorod-decorated graphene sheets have an expanded light absorption range. ► TiO 2 nanorod-decorated graphene sheets showed unprecedented photocatalytic activity. - Abstract: The titanium dioxide (TiO 2 ) nanorod-decorated graphene sheets photocatalysts with different TiO 2 nanorods population have been synthesized by a simple non-hydrolytic sol–gel approach. Electron microscopy and X-ray diffraction analysis indicated that the TiO 2 nanorods are well-dispersed and successfully anchored on the graphene sheet surface through the formation of covalent bonds between Ti and C atoms. The photocatalytic activities are evaluated in terms of the efficiencies of photodecomposition and adsorption of methylene blue (MB) in aqueous solution under visible-light irradiation. The as-synthesized TiO 2 nanorod-decorated graphene sheets showed unprecedented photodecomposition efficiency compared to the pristine TiO 2 nanorods and the commercial TiO 2 (P-25, Degussa) under visible-light. It is believed that this predominant photocatalytic activity is due to the synergistic contribution of both a retarded charge recombination rate caused by a high electronic mobility of graphene and an increased surface area originated from nanometer-sized TiO 2 nanorods. Furthermore, photoelectrochemical study is performed to give deep insights into the primary roles of graphene that determines the photocatalytic activity.

  4. Controlled Defects of Zinc Oxide Nanorods for Efficient Visible Light Photocatalytic Degradation of Phenol

    Jamal Al-Sabahi

    2016-03-01

    Full Text Available Environmental pollution from human and industrial activities has received much attention as it adversely affects human health and bio-diversity. In this work we report efficient visible light photocatalytic degradation of phenol using supported zinc oxide (ZnO nanorods and explore the role of surface defects in ZnO on the visible light photocatalytic activity. ZnO nanorods were synthesized on glass substrates using a microwave-assisted hydrothermal process, while the surface defect states were controlled by annealing the nanorods at various temperatures and were characterized by photoluminescence and X-ray photoelectron spectroscopy. High performance liquid chromatography (HPLC was used for the evaluation of phenol photocatalytic degradation. ZnO nanorods with high surface defects exhibited maximum visible light photocatalytic activity, showing 50% degradation of 10 ppm phenol aqueous solution within 2.5 h, with a degradation rate almost four times higher than that of nanorods with lower surface defects. The mineralization process of phenol during degradation was also investigated, and it showed the evolution of different photocatalytic byproducts, such as benzoquinone, catechol, resorcinol and carboxylic acids, at different stages. The results from this study suggest that the presence of surface defects in ZnO nanorods is crucial for its efficient visible light photocatalytic activity, which is otherwise only active in the ultraviolet region.

  5. Y-doping TiO2 nanorod arrays for efficient perovskite solar cells

    Deng, Xinlian; Wang, Yanqing; Cui, Zhendong; Li, Long; Shi, Chengwu

    2018-05-01

    To improve the electron transportation in TiO2 nanorod arrays and charge separation in the interface of TiO2/perovskite, Y-doping TiO2 nanorod arrays with the length of 200 nm, diameter of 11 nm and areal density of 1050 μm-2 were successfully prepared by the hydrothermal method and the influence of Y/Ti molar ratios of 0%, 3%, 5% in the hydrothermal grown solutions on the growth of TiO2 nanorod arrays was investigated. The results revealed that the appropriate Y/Ti molar ratios can increase the areal density of the corresponding TiO2 nanorod arrays and improve the charge separation in the interface of the TiO2/perovskite. The Y-doping TiO2 nanorod array perovskite solar cells with the Y/Ti molar ratio of 3% exhibited a photoelectric conversion efficiency (PCE) of 18.11% along with an open-circuit voltage (Voc) of 1.06 V, short-circuit photocurrent density (Jsc) of 22.50 mA cm-2 and fill factor (FF) of 76.16%, while the un-doping TiO2 nanorod array perovskite solar cells gave a PCE of 16.42% along with Voc of 1.04 V, Jsc of 21.66 mA cm-2 and FF of 72.97%.

  6. An efficient route to Cu_2O nanorod array film for high-performance Li-ion batteries

    Yang, Yumei; Wang, Kun; Yang, Zeheng; Zhang, Yingmeng; Gu, Heyun; Zhang, Weixin; Li, Errui; Zhou, Chen

    2016-01-01

    Fabrication of well-organized one-dimensional nanostructured arrays on conducting substrates as binder free electrodes allows us to synergize and integrate multi-functionalities into lithium ion batteries. In this contribution, we report a metal-induced thermal reduction (MITR) method to prepare free-standing Cu_2O nanorod array film with average diameters of 400 ± 100 nm and lengths of several microns on copper substrates by direct thermal reduction of Cu(OH)_2 nanorod arrays on copper foils in nitrogen atmosphere at 500 °C. The presence of Cu substrates reduces the Cu(OH)_2 to Cu_2O and decreases the reduction temperature significantly through changing the reaction Gibbs energy. Compared with some previously-reported methods about thermal reduction, the MITR method is facile, controllable, efficient and low energy consumption. The free-standing Cu_2O nanorod array film on Cu substrates as anode can achieve high rate capability (315 mAh g"−"1 at 10 C) and good cyclability (358 mAh g"−"1 after 200 cycles at 1 C), demonstrating their excellent electrochemical performance in lithium ion batteries, which results from relatively faster electron and ion transport, easier electrolyte diffusion and better accommodation of strains from the repeated conversion reactions based on their one-dimensional nanostructured arrays. - Highlights: • A metal-induced thermal reduction method was used to prepare Cu_2O nanorod array film. • Copper substrate takes an important part in the conversion of Cu(OH)_2 to Cu_2O. • The Cu_2O films show excellent electrochemical properties as anode for Li-ion battery.

  7. Efficient nanorod-based amorphous silicon solar cells with advanced light trapping

    Kuang, Y.; Lare, M. C. van; Polman, A.; Veldhuizen, L. W.; Schropp, R. E. I.; Rath, J. K.

    2015-01-01

    We present a simple, low-cost, and scalable approach for the fabrication of efficient nanorod-based solar cells. Templates with arrays of self-assembled ZnO nanorods with tunable morphology are synthesized by chemical bath deposition using a low process temperature at 80 °C. The nanorod templates are conformally coated with hydrogenated amorphous silicon light absorber layers of 100 nm and 200 nm thickness. An initial efficiency of up to 9.0% is achieved for the optimized design. External quantum efficiency measurements on the nanorod cells show a substantial photocurrent enhancement both in the red and the blue parts of the solar spectrum. Key insights in the light trapping mechanisms in these arrays are obtained via a combination of three-dimensional finite-difference time-domain simulations, optical absorption, and external quantum efficiency measurements. Front surface patterns enhance the light incoupling in the blue, while rear side patterns lead to enhanced light trapping in the red. The red response in the nanorod cells is limited by absorption in the patterned Ag back contact. With these findings, we develop and experimentally realize a further advanced design with patterned front and back sides while keeping the Ag reflector flat, showing significantly enhanced scattering from the back reflector with reduced parasitic absorption in the Ag and thus higher photocurrent generation. Many of the findings in this work can serve to provide insights for further optimization of nanostructures for thin-film solar cells in a broad range of materials

  8. Efficient nanorod-based amorphous silicon solar cells with advanced light trapping

    Kuang, Y. [Physics of Devices, Debye Institute for Nanomaterials Science, Utrecht University, High Tech Campus, Building 21, 5656 AE Eindhoven (Netherlands); Department of Applied Physics, Plasma & Materials Processing, Eindhoven University of Technology (TUE), P.O. Box 513, 5600 MB Eindhoven (Netherlands); Lare, M. C. van; Polman, A. [Center for Nanophotonics, FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam (Netherlands); Veldhuizen, L. W.; Schropp, R. E. I., E-mail: r.e.i.schropp@tue.nl [Department of Applied Physics, Plasma & Materials Processing, Eindhoven University of Technology (TUE), P.O. Box 513, 5600 MB Eindhoven (Netherlands); Rath, J. K. [Physics of Devices, Debye Institute for Nanomaterials Science, Utrecht University, High Tech Campus, Building 21, 5656 AE Eindhoven (Netherlands)

    2015-11-14

    We present a simple, low-cost, and scalable approach for the fabrication of efficient nanorod-based solar cells. Templates with arrays of self-assembled ZnO nanorods with tunable morphology are synthesized by chemical bath deposition using a low process temperature at 80 °C. The nanorod templates are conformally coated with hydrogenated amorphous silicon light absorber layers of 100 nm and 200 nm thickness. An initial efficiency of up to 9.0% is achieved for the optimized design. External quantum efficiency measurements on the nanorod cells show a substantial photocurrent enhancement both in the red and the blue parts of the solar spectrum. Key insights in the light trapping mechanisms in these arrays are obtained via a combination of three-dimensional finite-difference time-domain simulations, optical absorption, and external quantum efficiency measurements. Front surface patterns enhance the light incoupling in the blue, while rear side patterns lead to enhanced light trapping in the red. The red response in the nanorod cells is limited by absorption in the patterned Ag back contact. With these findings, we develop and experimentally realize a further advanced design with patterned front and back sides while keeping the Ag reflector flat, showing significantly enhanced scattering from the back reflector with reduced parasitic absorption in the Ag and thus higher photocurrent generation. Many of the findings in this work can serve to provide insights for further optimization of nanostructures for thin-film solar cells in a broad range of materials.

  9. 16.1% Efficient Hysteresis-Free Mesostructured Perovskite Solar Cells Based on Synergistically Improved ZnO Nanorod Arrays

    Mahmood, Khalid; Swain, Bhabani Sankar; Amassian, Aram

    2015-01-01

    Significant efficiency improvements are reported in mesoscopic perovskite solar cells based on the development of a low-temperature solution-processed ZnO nanorod (NR) array exhibiting higher NR aspect ratio, enhanced electron density

  10. Physical and chemical contributions of a plasma treatment in the growth of ZnO nanorods

    Jang, J.T. [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Ryu, H., E-mail: hhryu@inje.ac.kr [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Lee, W.J. [Department of Materials and Components Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of); Yun, J. [Department of Nano Science and Engineering, Kyungnam University, Changwon, Gyeongnam 631-701 (Korea, Republic of)

    2013-11-15

    Highlights: •ZnO nanorods were grown by hydrothermal synthesis. •Oxygen plasma was done on the surface of seed ZnO nanorods. •The ZnO nanorods with and without plasma treatment were characterized. •The results showed that the optical and structural properties of ZnO nanorods with plasma treatment were enhanced. -- Abstract: We analyzed the enhancement of optical and structural properties of ZnO nanorods by using a plasma treatment. In this study, seed ZnO nanorods were grown by hydrothermal synthesis for 1 h on a ZnO buffered Si substrate. The seed ZnO nanorods were then treated with an oxygen plasma. Next, ZnO was grown for an additional 4 h by hydrothermal synthesis. The resultant ZnO nanorods were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), electron energy loss spectroscopy (EELS), X-ray diffraction (XRD) and photoluminescence (PL). The measurements showed that the plasma treatment of the seed ZnO nanorods increased the roughness of the buffer layer and the concentration of oxygen ions on the surfaces of the seed ZnO nanorods and the buffer layer, leading to improved optical and structural properties. In this study, we found that the plasma treatment on the seed ZnO nanorods enhanced the optical and structural properties of the ZnO nanorods.

  11. Hierarchical Layered WS2 /Graphene-Modified CdS Nanorods for Efficient Photocatalytic Hydrogen Evolution.

    Xiang, Quanjun; Cheng, Feiyue; Lang, Di

    2016-05-10

    Graphene-based ternary composite photocatalysts with genuine heterostructure constituents have attracted extensive attention in photocatalytic hydrogen evolution. Here we report a new graphene-based ternary composite consisting of CdS nanorods grown on hierarchical layered WS2 /graphene hybrid (WG) as a high-performance photocatalyst for hydrogen evolution under visible light irradiation. The optimal content of layered WG as a co-catalyst in the ternary CdS/WS2 /graphene composites was found to be 4.2 wt %, giving a visible light photocatalytic H2 -production rate of 1842 μmol h(-1)  g(-1) with an apparent quantum efficiency of 21.2 % at 420 nm. This high photocatalytic H2 -production activity is due to the deposition of CdS nanorods on layered WS2 /graphene sheets, which can efficiently suppress charge recombination, improve interfacial charge transfer, and provide reduction active sites. The proposed mechanism for the enhanced photocatalytic activity of CdS nanorods modified with hierarchical layered WG was further confirmed by transient photocurrent response. This work shows that a noble-metal-free hierarchical layered WS2 /graphene nanosheets hybrid can be used as an effective co-catalyst for photocatalytic water splitting. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Tunable light extraction efficiency of GaN light emitting diodes by ZnO nanorod arrays

    Chao, C H; Lin, W H; Lin, C F; Chen, C H; Changjean, C H

    2009-01-01

    We report the influence of ZnO nanorod arrays (NRAs) on the light extraction efficiency of GaN light emitting diodes (LEDs). Our investigation indicates that the output light intensity of the device exhibits a periodic oscillation as a function of the rod length. The variation of light extraction efficiency is caused by the Fabry–Perot resonance of the film composed of the nanorods. The theoretical analysis shows a good agreement with the measurement results. Our study reveals a method to control the output light extraction efficiency of GaN LEDs via a simple solution-based synthesized ZnO NRAs

  13. Amorphous MoS{sub x} on CdS nanorods for highly efficient photocatalytic hydrogen evolution

    Li, Xiaofang; Tang, Chaowan; Zheng, Qun; Shao, Yu; Li, Danzhen, E-mail: dzli@fzu.edu.cn

    2017-02-15

    Loading cocatalyst on semiconductors was crucially necessary for improving the photocatalytic hydrogen evolution. Amorphous MoS{sub x} as a novel and noble metal-free cocatalyst was loaded on CdS nanorods by a simple photodeposition method. Efficient hydrogen evolution with amount of 15 mmol h{sup −1} g{sup −1} was observed over the MoS{sub x} modified CdS nanorods, which was about 6 times higher than that by using Pt as cocatalyst. Meanwhile, with MoS{sub x} cocatalyst, the efficiency of CdS nanorods was superior to that of CdS nanoparticles and bulk CdS. No deactivation could be observed in the efficiency of MoS{sub x} modified CdS nanorods under irradiation for successive 10 h. Further experimental results indicated that the efficient electrons transfer, low overpotential of hydrogen evolution and active S atoms over the MoS{sub x} modified CdS nanorods were responsible for the higher efficiency. Our results provided guidance for synthesizing noble metal-free materials as cocatalyst for photocatalytic hydrogen evolution. - Graphical abstract: Photodeposition of amorphous MoS{sub x} on CdS nanorods for highly efficient photocatalytic hydrogen evolution. - Highlights: • Amorphous MoSx cocatalyst was loaded on CdS NRs by a simple photodeposition. • MoS{sub x}/CdS NRs exhibited 6 times higher hydrogen evolution efficiency than Pt/CdS NRs. • The hydrogen evolution of MoS{sub x}/CdS NRs linearly increased with prolonging time. • Lower overpotential and efficient electron transfer were observed over MoS{sub x}/CdS NRs.

  14. Efficient visible light photocatalysis of benzene, toluene, ethylbenzene and xylene (BTEX) in aqueous solutions using supported zinc oxide nanorods

    Bora, Tanujjal; Al-Abri, Mohammed; Dutta, Joydeep

    2017-01-01

    Benzene, toluene, ethylbenzene and xylenes (BTEX) are some of the common environmental pollutants originating mainly from oil and gas industries, which are toxic to human as well as other living organisms in the ecosystem. Here we investigate photocatalytic degradation of BTEX under visible light irradiation using supported zinc oxide (ZnO) nanorods grown on glass substrates using a microwave assisted hydrothermal method. ZnO nanorods were characterized by electron microscopy, X-ray diffraction (XRD), specific surface area, UV/visible absorption and photoluminescence spectroscopy. Visible light photocatalytic degradation products of BTEX are studied for individual components using gas chromatograph/mass spectrometer (GC/MS). ZnO nanorods with significant amount of electronic defect states, due to the fast crystallization of the nanorods under microwave irradiation, exhibited efficient degradation of BTEX under visible light, degrading more than 80% of the individual BTEX components in 180 minutes. Effect of initial concentration of BTEX as individual components is also probed and the photocatalytic activity of the ZnO nanorods in different conditions is explored. Formation of intermediate byproducts such as phenol, benzyl alcohol, benzaldehyde and benzoic acid were confirmed by our HPLC analysis which could be due to the photocatalytic degradation of BTEX. Carbon dioxide was evaluated and showed an increasing pattern over time indicating the mineralization process confirming the conversion of toxic organic compounds into benign products. PMID:29261711

  15. Growing vertical ZnO nanorod arrays within graphite: efficient isolation of large size and high quality single-layer graphene.

    Ding, Ling; E, Yifeng; Fan, Louzhen; Yang, Shihe

    2013-07-18

    We report a unique strategy for efficiently exfoliating large size and high quality single-layer graphene directly from graphite into DMF dispersions by growing ZnO nanorod arrays between the graphene layers in graphite.

  16. Interspace modification of titania-nanorod arrays for efficient mesoscopic perovskite solar cells

    Chen, Peng; Jin, Zhixin; Wang, Yinglin; Wang, Meiqi; Chen, Shixin; Zhang, Yang; Wang, Lingling; Zhang, Xintong; Liu, Yichun

    2017-04-01

    Morphology of electron transport layers (ETLs) has an important influence on the device architecture and electronic processes of mesostructured solar cells. In this work, we thoroughly investigated the effect of the interspace of TiO2 nanorod (NR) arrays on the photovoltaic performance of the perovskite solar cells (PSCs). Along with the interspace in TiO2-NR arrays increasing, the thickness as well as the crystal size of perovskite capping layer are reduced accordingly, and the filling of perovskite in the channel becomes incomplete. Electrochemical impedance spectroscopy measurements reveal that this variation of perovskite absorber layer, induced by interspace of TiO2 NR arrays, causes the change of charge recombination process at the TiO2/perovskite interface, suggesting that a balance between capping layer and the perovskite filling is critical to obtain high charge collection efficiency of PSCs. A power conversion efficiency of 10.3% could be achieved through careful optimization of interspace in TiO2-NR arrays. Our research will shed light on the morphology control of ETLs with 1D structure for heterojunction solar cells fabricated by solution-deposited method.

  17. Interspace modification of titania-nanorod arrays for efficient mesoscopic perovskite solar cells

    Chen, Peng; Jin, Zhixin; Wang, Yinglin; Wang, Meiqi; Chen, Shixin; Zhang, Yang; Wang, Lingling; Zhang, Xintong; Liu, Yichun

    2017-01-01

    Highlights: • The fabrication of perovskite solar cells utilizing TiO_2 NR arrays. • Investigation of the interspace effect of TiO_2 NR on perovskite layer. • Understanding of the balance between perovskite capping layer and pore filling. - Abstract: Morphology of electron transport layers (ETLs) has an important influence on the device architecture and electronic processes of mesostructured solar cells. In this work, we thoroughly investigated the effect of the interspace of TiO_2 nanorod (NR) arrays on the photovoltaic performance of the perovskite solar cells (PSCs). Along with the interspace in TiO_2-NR arrays increasing, the thickness as well as the crystal size of perovskite capping layer are reduced accordingly, and the filling of perovskite in the channel becomes incomplete. Electrochemical impedance spectroscopy measurements reveal that this variation of perovskite absorber layer, induced by interspace of TiO_2 NR arrays, causes the change of charge recombination process at the TiO_2/perovskite interface, suggesting that a balance between capping layer and the perovskite filling is critical to obtain high charge collection efficiency of PSCs. A power conversion efficiency of 10.3% could be achieved through careful optimization of interspace in TiO_2-NR arrays. Our research will shed light on the morphology control of ETLs with 1D structure for heterojunction solar cells fabricated by solution-deposited method.

  18. Interspace modification of titania-nanorod arrays for efficient mesoscopic perovskite solar cells

    Chen, Peng; Jin, Zhixin; Wang, Yinglin, E-mail: wangyl100@nenu.edu.cn; Wang, Meiqi; Chen, Shixin; Zhang, Yang; Wang, Lingling; Zhang, Xintong, E-mail: xtzhang@nenu.edu.cn; Liu, Yichun, E-mail: ycliu@nenu.edu.cn

    2017-04-30

    Highlights: • The fabrication of perovskite solar cells utilizing TiO{sub 2} NR arrays. • Investigation of the interspace effect of TiO{sub 2} NR on perovskite layer. • Understanding of the balance between perovskite capping layer and pore filling. - Abstract: Morphology of electron transport layers (ETLs) has an important influence on the device architecture and electronic processes of mesostructured solar cells. In this work, we thoroughly investigated the effect of the interspace of TiO{sub 2} nanorod (NR) arrays on the photovoltaic performance of the perovskite solar cells (PSCs). Along with the interspace in TiO{sub 2}-NR arrays increasing, the thickness as well as the crystal size of perovskite capping layer are reduced accordingly, and the filling of perovskite in the channel becomes incomplete. Electrochemical impedance spectroscopy measurements reveal that this variation of perovskite absorber layer, induced by interspace of TiO{sub 2} NR arrays, causes the change of charge recombination process at the TiO{sub 2}/perovskite interface, suggesting that a balance between capping layer and the perovskite filling is critical to obtain high charge collection efficiency of PSCs. A power conversion efficiency of 10.3% could be achieved through careful optimization of interspace in TiO{sub 2}-NR arrays. Our research will shed light on the morphology control of ETLs with 1D structure for heterojunction solar cells fabricated by solution-deposited method.

  19. Metal-Organic Frameworks Triggered High-Efficiency Li storage in Fe-Based Polyhedral Nanorods for Lithium-ion Batteries

    Shen, Lisha; Song, Huawei; Wang, Chengxin

    2017-01-01

    Recently, metal organic framework (MOF) nanostructures have been frequently reported in the field of energy storage, specifically for Li-ion or Na-ion storage. By inter-separating the active sites of metal cluster and organic ligands, MOF nanostructures are exceptionally promising for realizing fast ion exchange and high-efficiency transportation and addressing the intricate issues that the energy-intensive Li-ion batteries have faced over many years. The related ion-storage mechanism remains to be explored. Is the traditional redox reaction mechanism operative for these nanostructure, as it is for transitional metal oxide? Herein, taking [Fe_3O(BDC)_3(H_2O)_2(NO_3)]n (Fe-MIL-88B) as an example, an Fe-based metal organic polyhedral nanorods of MIL–88 B structure was designed as an anode for Li-ion storage. When tested at 60 mA g"−"1, the nanoporous Fe-MIL–88 B polyhedral nanorods retained a reversible capacity of 744.5 mAh g"−"1 for more than 400 cycles. Ex situ characterizations of the post-cycled electrodes revealed that both the transition metal ions and the organic ligands contributed to the high reversible specific capacity. The polyhedral nanorods electrodes held the metal-organic skeleton together throughout the battery operation, although in a somewhat different manner than the pristine ones. This further substantiated that some MOF nanostructures are more appropriate than others for stable lithiation/delithiation processes. State-of-the-art CR2032 full cells showed that a high capacity of 86.8 mAh g"−"1 that was retained after 100 cycles (herein, the capacity for the full cell was calculated based on both the weight of the anode and the cathode, and the charge-discharge rate was 0.25C), when commercial LiFePO_4 powders were used as the cathode.

  20. Improving the Efficiency of Dye-Sensitized Solar Cells by Growing Longer ZnO Nanorods on TiO2 Photoanodes

    Bao-gai Zhai

    2017-01-01

    Full Text Available By increasing the temperature of hydrothermal reactions from 70 to 100°C, vertically aligned ZnO nanorods were grown on the TiO2 thin film in the photoanode of dye-sensitized solar cells (DSSCs as the blocking layer to reduce the electron back recombinations at the TiO2/electrolyte interfaces. The length effects of ZnO nanorods on the photovoltaic performances of TiO2 based DSSCs were investigated by means of scanning electron microscope, X-ray diffractometer, photoluminescence spectrophotometer, and the photocurrent-voltage measurement. Under the illumination of 100 mW/cm2, the power conversion efficiency of DSSC with ZnO nanorods decorated TiO2 thin film as its photoanode can be increased nearly fourfold from 0.27% to 1.30% as the length of ZnO nanorods increases from 300 to 1600 nm. The enhanced efficiency of DSSC with ZnO nanorods decorated TiO2 thin film as the photoanode can be attributed to the larger surface area and the lower defect density in longer ZnO nanorods, which are in favor of more dye adsorption and more efficient transport in the photoanode.

  1. Fabrication of TiO2 nanoparticles/nanorod composite arrays via a two-step method for efficient dye-sensitized solar cells

    Jingyang Wang

    2014-12-01

    Full Text Available TiO2 nanoparticles/nanorod composite arrays were prepared on the F-doped tin oxide (FTO substrate through a two-step method of hydrothermal and d.c. magnetron sputtering. The microstructure and optical properties of the samples were characterized respectively by means of X-ray diffraction (XRD, field-emission scanning electron microscopy (FESEM and UV–vis spectrometer. The results showed that the TiO2 composite nanorod arrays possess the nature of high surface area for more dye molecule absorption and the strong light scattering effects. The dye sensitized solar cells (DSSCs based on TiO2 composite nanorod arrays exhibited a 80% improvement in the overall energy conversion efficiency compared with the pure TiO2 nanorod arrays photoanode.

  2. Cobalt selenide hollow nanorods array with exceptionally high electrocatalytic activity for high-efficiency quasi-solid-state dye-sensitized solar cells

    Jin, Zhitong; Zhang, Meirong; Wang, Min; Feng, Chuanqi; Wang, Zhong-Sheng

    2018-02-01

    In quasi-solid-state dye-sensitized solar cells (QSDSSCs), electron transport through a random network of catalyst in the counter electrode (CE) and electrolyte diffusion therein are limited by the grain boundaries of catalyst particles, thus diminishing the electrocatalytic performance of CE and the corresponding photovoltaic performance of QSDSSCs. We demonstrate herein an ordered Co0.85Se hollow nanorods array film as the Pt-free CE of QSDSSCs. The Co0.85Se hollow nanorods array displays excellent electrocatalytic activity for the reduction of I3- in the quasi-solid-state electrolyte with extremely low charge transfer resistance at the CE/electrolyte interface, and the diffusion of redox species within the Co0.85Se hollow nanorods array CE is pretty fast. The QSDSSC device with the Co0.85Se hollow nanorods array CE produces much higher photovoltaic conversion efficiency (8.35%) than that (4.94%) with the Co0.85Se randomly packed nanorods CE, against the control device with the Pt CE (7.75%). Moreover, the QSDSSC device based on the Co0.85Se hollow nanorods array CE presents good long-term stability with only 4% drop of power conversion efficiency after 1086 h one-sun soaking.

  3. Comparative efficiencies of photothermal destruction of malignant cells using antibody-coated silica-Au nanoshells, hollow Au/Ag nanospheres and Au nanorods

    Cheng, Fong-Yu; Chen, Chen-Tai; Yeh, Chen-Sheng, E-mail: csyeh@mail.ncku.edu.t [Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan (China)

    2009-10-21

    Three Au-based nanomaterials (silica-Au nanoshells, hollow Au/Ag nanospheres and Au nanorods) were evaluated for their comparative photothermal efficiencies at killing three types of malignant cells (A549 lung cancer cells, HeLa cervix cancer cells and TCC bladder cancer cells) using a CW NIR laser. Photodestructive efficiency was evaluated as a function of the number of nanoparticles required to destroy the cancer cells under 808 nm laser wavelength at fixed laser power. Of the three nanomaterials, silica/Au nanoshells needed the minimum number of particles to produce effective photodestruction, whereas Au nanorods needed the largest number of particles. Together with the calculated photothermal conversion efficiency, the photothermal efficiency rankings are silica-Au nanoshells > hollow Au/Ag nanospheres > Au nanorods. Additionally, we found that HeLa cells seem to present better heat tolerance than the other two cancer cell lines.

  4. High-efficiency super capacitors based on hetero-structured α-MnO2 nanorods

    Ghouri, Zafar Khan; Shaheer Akhtar, M.; Zahoor, Awan; Barakat, Nasser A.M.; Han, Weidong; Park, Mira; Pant, Bishweshwar; Saud, Prem Singh; Lee, Cho Hye; Kim, Hak Yong

    2015-01-01

    Highlights: • Hetero-structured α-MnO 2 nanorods are prepared by a facile hydrothermal route. • It is applied as active electrode materials for supercapacitor. • A high specific capacitance of 298 Fg −1 with a superior long term cyclic stability is achieved. • Supercapacitor shows high specific capacitance retention 94% after 1000 cycles. - Abstract: Hetero-structured manganese dioxide nanorods with α phase (α-MnO 2 ) were prepared by a facile hydrothermal route at low temperature. X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption–desorption measurements were used to characterize the prepared hetero-structured α-MnO 2 nanorods. Supercapacitive performance of the hetero-structured α-MnO 2 nanomaterials as active electrode material was evaluated by cyclic voltammetry (CV) in alkaline medium. The MnO 2 hetero-structure with 2 × 2 tunnels constructed from double chains of octahedral [MnO 6 ] structure yield a significantly high specific capacitance of 298 Fg −1 at 5 mV s −1 and demonstrated a superior long term cyclic stability, with specific capacitance retention about 94% after 1000 cycles. The superior supercapacitive performance of the hetero-structured α-MnO 2 electrode is due to its high specific surface area and unique hierarchy architecture which facilitate fast electron and ion transport

  5. PEGylated (NH4)xWO3 nanorods as efficient and stable multifunctional nanoagents for simultaneous CT imaging and photothermal therapy of tumor.

    Macharia, Daniel K; Tian, Qiyun; Chen, Liang; Sun, Yingqi; Yu, Nuo; He, Chuanglong; Wang, Han; Chen, Zhigang

    2017-09-01

    The simultaneous imaging and photothermal therapy of tumors have attracted much attention, and a prerequisite is to obtain multifunctional nanomaterials. Ideally, one kind of nanoparticles with single component can be used as both imaging agent and photothermal agent. Herein, we have developed the PEGylated (NH 4 ) x WO 3 (denoted as (NH 4 ) x WO 3 -PEG) nanorods as multifunctional nanoparticles with single semiconductor component. (NH 4 ) x WO 3 -PEG nanorods with about 30nm diameter and length of several hundred nanometers have been obtained through a solvothermal synthesis-PEGylation two-step route. Under the irradiation of 980-nm laser with intensity of 0.72Wcm -2 , aqueous dispersion of (NH 4 ) x WO 3 -PEG nanorods (0.67-5.44mmol/L) displays high elevation (17.6-34.5°C) of temperature in 400s, accompanied by an excellent long-term photothermal stability. Furthermore, (NH 4 ) x WO 3 -PEG nanorods exhibit as high as 6 times X-ray attenuation ability compared to that of the clinically used iodine-based X-ray computed tomography (CT) contrast agent (Iopromide). More importantly, after PBS solution of (NH 4 ) x WO 3 -PEG nanorods is injected into the tumor of mice, the tumor can be effectively detected by CT imaging. Moreover, cancer cells in vivo can be further destroyed by the photothermal effects of (NH 4 ) x WO 3 -PEG nanorods, under the irradiation of 980-nm laser with the safe intensity of 0.72Wcm -2 for 10min. Therefore, (NH 4 ) x WO 3 -PEG nanorods can be used as a new kind of stable and efficient multifunctional nanoagent with single component for simultaneous CT imaging and photothermal therapy of tumor. Copyright © 2017. Published by Elsevier B.V.

  6. Enhancement of Perovskite Solar Cells Efficiency using N-Doped TiO2 Nanorod Arrays as Electron Transfer Layer.

    Zhang, Zhen-Long; Li, Jun-Feng; Wang, Xiao-Li; Qin, Jian-Qiang; Shi, Wen-Jia; Liu, Yue-Feng; Gao, Hui-Ping; Mao, Yan-Li

    2017-12-01

    In this paper, N-doped TiO 2 (N-TiO 2 ) nanorod arrays were synthesized with hydrothermal method, and perovskite solar cells were fabricated using them as electron transfer layer. The solar cell performance was optimized by changing the N doping contents. The power conversion efficiency of solar cells based on N-TiO 2 with the N doping content of 1% (N/Ti, atomic ratio) has been achieved 11.1%, which was 14.7% higher than that of solar cells based on un-doped TiO 2 . To get an insight into the improvement, some investigations were performed. The structure was examined with X-ray powder diffraction (XRD), and morphology was examined by scanning electron microscopy (SEM). Energy dispersive spectrometer (EDS) and Tauc plot spectra indicated the incorporation of N in TiO 2 nanorods. Absorption spectra showed higher absorption of visible light for N-TiO 2 than un-doped TiO 2 . The N doping reduced the energy band gap from 3.03 to 2.74 eV. The photoluminescence (PL) and time-resolved photoluminescence (TRPL) spectra displayed the faster electron transfer from perovskite layer to N-TiO 2 than to un-doped TiO 2 . Electrochemical impedance spectroscopy (EIS) showed the smaller resistance of device based on N-TiO 2 than that on un-doped TiO 2 .

  7. Contribution to the strategy of energy efficiency

    Ciconkov, Risto

    2003-01-01

    An explanation for the greenhouse effect, i.e.global warming and reasons which contribute to this effect. Greenhouse gasses (GHG) and GWP (Global Warming Potential) as a factor for estimating their contributing on the greenhouse effect. Indicators of the climate change in the previous period and projecting of likely scenarios for the future. Consequences on the environment and human activities: industry, energy, agriculture, water resource. The main lines of the Kyoto Protocol and problems in its realization. Suggestions to the country strategy concerning to the acts of the Kyoto Protocol. A special attention is pointed out on the energy, its resource, the structure of energy consumption and energy efficiency. Main sectors of the energy efficiency: buildings, industry and transport. Buildings: importance of heat insulation. District heating, suggestions for space heating. Heat pumps and CHP. Air conditioning and refrigeration. Industry: process heating, and integrated energy system heat recovery, refrigeration, compressed air. Need of quality maintenance and servicing. Monitoring and automatic control. Education for energy and its saving. (Original)

  8. TiO2 nanocrystals decorated Z-schemed core-shell CdS-CdO nanorod arrays as high efficiency anodes for photoelectrochemical hydrogen generation.

    Li, Chia-Hsun; Hsu, Chan-Wei; Lu, Shih-Yuan

    2018-07-01

    TiO 2 nanocrystals decorated core-shell CdS-CdO nanorod arrays, TiO 2 @CdO/CdS NR, were fabricated as high efficiency anodes for photoelctrochemical hydrogen generation. The novel sandwich heterostructure was constructed from first growth of CdS nanorod arrays on a fluorine doped tin oxide (FTO) substrate with a hydrothermal process, followed by in situ generation of CdO thin films of single digit nanometers from the CdS nanorod surfaces through thermal oxidation, and final decoration of TiO 2 nanocrystals of 10-20 nm via a successive ionic layer absorption and reaction process. The core-shell CdS-CdO heterostructure possesses a Z-scheme band structure to enhance interfacial charge transfer, facilitating effective charge separation to suppress electron-hole recombination within CdS for much improved current density generation. The final decoration of TiO 2 nanocrystals passivates surface defects and trap states of CdO, further suppressing surface charge recombination for even higher photovoltaic conversion efficiencies. The photoelectrochemical performances of the plain CdS nanorod array were significantly improved with the formation of the sandwich heterostructure, achieving a photo current density of 3.2 mA/cm 2 at 1.23 V (vs. RHE), a 141% improvement over the plain CdS nanorod array and a 32% improvement over the CdO/CdS nanorod array. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. A Facile Strategy to Prepare Dendrimer-stabilized Gold Nanorods with Sub-10-nm Size for Efficient Photothermal Cancer Therapy

    Wang, Xinyu; Wang, Hanling; Wang, Yitong; Yu, Xiangtong; Zhang, Sanjun; Zhang, Qiang; Cheng, Yiyun

    2016-03-01

    Gold (Au) nanoparticles are promising photothermal agents with the potential of clinical translation. However, the safety concerns of Au photothermal agents including the potential toxic compositions such as silver and copper elements in their structures and the relative large size-caused retention and accumulation in the body post-treatment are still questionable. In this article, we successfully synthesized dendrimer-stabilized Au nanorods (DSAuNRs) with pure Au composition and a sub-10-nm size in length, which represented much higher photothermal effect compared with dendrimer-encapsulated Au nanoparticles due to their significantly enhanced absorption in the near-infrared region. Furthermore, glycidol-modified DSAuNRs exhibited the excellent biocompatibility and further showed the high photothermal efficiency of killing cancer cells in vitro and retarding tumor growth in vivo. The investigation depicted an optimal photothermal agent with the desirable size and safe composition.

  10. Ag2WO4 nanorods decorated with AgI nanoparticles: Novel and efficient visible-light-driven photocatalysts for the degradation of water pollutants

    Shijie Li

    2018-04-01

    Full Text Available To develop efficient and stable visible-light-driven (VLD photocatalysts for pollutant degradation, we synthesized novel heterojunction photocatalysts comprised of AgI nanoparticle-decorated Ag2WO4 nanorods via a facile method. Various characterization techniques, including XRD, SEM, TEM, EDX, and UV–vis DRS were used to investigate the morphology and optical properties of the as-prepared AgI/Ag2WO4 catalyst. With AgI acting as the cocatalyst, the resulting AgI/Ag2WO4 heterostructure shows excellent performance in degrading toxic, stable pollutants such as rhodamine B (RhB, methyl orange (MO and para-chlorophenol (4-CP. The high performance is attributed to the enhanced visible-light absorption properties and the promoted separation efficiency of charge carriers through the formation of the heterojunction between AgI and Ag2WO4. Additionally, AgI/Ag2WO4 exhibits durable stability. The active species trapping experiment reveals that active species (O2•− and h+ dominantly contribute to RhB degradation. The AgI/Ag2WO4 heterojunction photocatalyst characterized in this work holds great potential for remedying environmental issues due to its simple preparation method and excellent photocatalytic performance.

  11. 16.1% Efficient Hysteresis-Free Mesostructured Perovskite Solar Cells Based on Synergistically Improved ZnO Nanorod Arrays

    Mahmood, Khalid

    2015-06-01

    Significant efficiency improvements are reported in mesoscopic perovskite solar cells based on the development of a low-temperature solution-processed ZnO nanorod (NR) array exhibiting higher NR aspect ratio, enhanced electron density, and substantially reduced work function than conventional ZnO NRs. These features synergistically result in hysteresis-free, scan-independent, and stabilized devices with an efficiency of 16.1%. Electron-rich, nitrogen-doped ZnO (N:ZnO) NR-based electron transporting materials (ETMs) with enhanced electron mobility produced using ammonium acetate show consistently higher efficiencies by one to three power points than undoped ZnO NRs. Additionally, the preferential electrostatic interaction between the -nonpolar facets of N:ZnO and the conjugated polyelectrolyte polyethylenimine (PEI) has been relied on to promote the hydrothermal growth of high aspect ratio NR arrays and substantially improve the infiltration of the perovskite light absorber into the ETM. Using the same interactions, a conformal PEI coating on the electron-rich high aspect ratio N:ZnO NR arrays is -successfully applied, resulting in a favorable work function shift and altogether leading to the significant boost in efficiency from <10% up to >16%. These results largely surpass the state-of-the-art PCE of ZnO-based perovskite solar cells and highlight the benefits of synergistically combining mesoscale control with doping and surface modification. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Aqueous chemical growth of free standing vertical ZnO nanoprisms, nanorods and nanodiskettes with improved texture co-efficient and tunable size uniformity

    Ram, S.D.G. [Bharath Niketan Engineering College, Department of Physics, Aundipatti (India); Ravi, G.; Mahalingam, T. [Alagappa University, Department of Physics, Karaikudi (India); Athimoolam, A. [Fatima Michael College of Engineering and Technology, Department of Physics, Madurai (India); Kulandainathan, M.A. [Central Electro Chemical Research Institute, Karaikudi (India)

    2011-12-15

    Tuning the morphology, size and aspect ratio of free standing ZnO nanostructured arrays by a simple hydrothermal method is reported. Pre-coated ZnO seed layers of two different thicknesses ({approx}350 nm or 550 nm) were used as substrates to grow ZnO nanostructures for the study. Various parameters such as chemical ambience, pH of the solution, strength of the Zn{sup 2+} atoms and thickness of seed bed are varied to analyze their effects on the resultant ZnO nanostructures. Vertically oriented hexagonal nanorods, multi-angular nanorods, hexagonal diskette and popcorn-like nanostructures are obtained by altering the experimental parameters. All the produced nanostructures were analysed by X-ray powder diffraction analysis and found to be grown in the (002) orientation of wurtzite ZnO. The texture co-efficient of ZnO layer was improved by combining a thick seed layer with higher cationic strength. Surface morphological studies reveal various nanostructures such as nanorods, diskettes and popcorn-like structures based on various preparation conditions. The optical property of the closest packed nanorods array was recorded by UV-VIS spectrometry, and the band gap value simulated from the results reflect the near characteristic band gap of ZnO. The surface roughness profile taken from the Atomic Force Microscopy reveals a roughness of less than 320 nm. (orig.)

  13. An efficient way to prepare silver nanorods in high concentration by polyol method without adding other metal or salt

    Chen Yong; Guan Jianguo; Xie Hongquan

    2012-01-01

    Using ethylene glycol as solvent and reductant, polyvinyl pyrrolidone(PVP) as capping agent under the action of appropriately preformed silver crystal seeds and controlled addition rates of silver nitrate and PVP solution, silver nanorods with length of 2–15 μm and diameter of 200–880 nm can be obtained in high concentration of AgNO 3 as 0.50 M. In the absence of the preformed seeds, nanorods cannot be obtained as the main product, if the AgNO 3 concentration is over 0.10 M. It is necessary to use the appropriately preformed silver crystal seeds for the high concentration preparation of silver nanorods. Transmission Electron Microscopy images showed that Ag seeds preformed at appropriate silver nitrate concentrations exhibited the multiply twinned particles of decahedral shape(MTPs), which formed Ag nanorods in the presence of PVP. Through study of the effects of various factors on the nanostructure of silver, the favorable conditions are: appropriately preformed seeds concentration at 6.54–9.81 mM, addition rate of AgNO 3 solution at 0.30–0.43 mL min −1 and molar ratio of PVP/AgNO 3 at 1.1–1.4, in order to control the crystal growth rate of silver matching the reduction rate of AgNO 3 by ethylene glycol. The nanorods obtained were characterized by Scanning Electron Microscopy, EDX, XRD, Raman spectrometry, Infrared Spectrophotometry and Ultraviolet Spectrophotometry. On the base of the above results, the mechanism of rates matching for obtaining silver nanorods was briefly discussed. This method is a simple, facile and economical method using high concentration with high yield without using other metal or salt to massively synthesize silver nanorods through adding preformed silver seeds to control the reduction rate of silver nitrate and the crystal growth rate of silver nanorods. As compared to the conventional polyol method using lower silver nitrate concentration, this method can save ethylene glycol used and time of operation and the as

  14. Efficient seed-mediated method for the large-scale synthesis of Au nanorods

    Ahmed, Waqqar; Bhatti, Arshad Saleem; Ruitenbeek, Jan M. van

    2017-01-01

    Seed-mediated methods are widely followed for the synthesis of Au nanorods (NRs). However, mostly dilute concentrations of the Au precursor (HAuCl_4) are used in the growth solution, which leads to a low final concentration of NRs. Attempts of increasing the concentration of NRs by simply increasing the concentration of HAuCl_4, other reagents in the growth solution and seeds lead to a faster growth kinetics which is not favourable for NR growth. Herein, we demonstrate that the increase in growth kinetics for high concentrations of reagents in growth solution can be neutralised by decreasing the pH of the solution. The synthesis of the NRs can be scaled up by using higher concentrations of reagents and adding an optimum concentration of HCl in the growth solution. The concentration of HAuCl_4 in the growth solution can be increased up to 5 mM, and 10–20 times more NRs can be synthesised for the same reaction volume compared to that of the conventional seed-mediated method. We have also noticed that a cetyltrimethylammonium bromide (CTAB)-to-HAuCl_4 molar ratio of 50 is sufficient for obtaining high yield of NRs.

  15. Controlling the conduction band offset for highly efficient ZnO nanorods based perovskite solar cell

    Dong, Juan; Shi, Jiangjian; Li, Dongmei; Luo, Yanhong; Meng, Qingbo

    2015-01-01

    The mechanism of charge recombination at the interface of n-type electron transport layer (n-ETL) and perovskite absorber on the carrier properties in the perovskite solar cell is theoretically studied. By solving the one dimensional diffusion equation with different boundary conditions, it reveals that the interface charge recombination in the perovskite solar cell can be suppressed by adjusting the conduction band offset (ΔE C ) at ZnO ETL/perovskite absorber interface, thus leading to improvements in cell performance. Furthermore, Mg doped ZnO nanorods ETL has been designed to control the energy band levels. By optimizing the doping amount of Mg, the conduction band minimum of the Mg doped ZnO ETL has been raised up by 0.29 eV and a positive ΔE C of about 0.1 eV is obtained. The photovoltage of the cell is thus significantly increased due to the relatively low charge recombination

  16. Efficient seed-mediated method for the large-scale synthesis of Au nanorods

    Ahmed, Waqqar; Bhatti, Arshad Saleem [COMSATS Institute of Information Technology, Department of Physics (Pakistan); Ruitenbeek, Jan M. van, E-mail: Ruitenbeek@physics.leidenuniv.nl [Leiden University, Huygens-Kamerlingh Onnes Laboratory (Netherlands)

    2017-03-15

    Seed-mediated methods are widely followed for the synthesis of Au nanorods (NRs). However, mostly dilute concentrations of the Au precursor (HAuCl{sub 4}) are used in the growth solution, which leads to a low final concentration of NRs. Attempts of increasing the concentration of NRs by simply increasing the concentration of HAuCl{sub 4}, other reagents in the growth solution and seeds lead to a faster growth kinetics which is not favourable for NR growth. Herein, we demonstrate that the increase in growth kinetics for high concentrations of reagents in growth solution can be neutralised by decreasing the pH of the solution. The synthesis of the NRs can be scaled up by using higher concentrations of reagents and adding an optimum concentration of HCl in the growth solution. The concentration of HAuCl{sub 4} in the growth solution can be increased up to 5 mM, and 10–20 times more NRs can be synthesised for the same reaction volume compared to that of the conventional seed-mediated method. We have also noticed that a cetyltrimethylammonium bromide (CTAB)-to-HAuCl{sub 4} molar ratio of 50 is sufficient for obtaining high yield of NRs.

  17. Short-length and high-density TiO{sub 2} nanorod arrays for the efficient charge separation interface in perovskite solar cells

    Xiao, Guannan; Shi, Chengwu, E-mail: shicw506@foxmail.com; Zhang, Zhengguo; Li, Nannan; Li, Long

    2017-05-15

    The TiO{sub 2} nanorod arrays with the length of 70 nm, the diameter of 20 nm, and the areal density of 1000 µm{sup −2} were firstly prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 60 min. Over-500 nm-thickness CH{sub 3}NH{sub 3}PbI{sub 3−x}Br{sub x} absorber layers were successfully obtained by sequential deposition routes using 1.7 M PbI{sub 2}·DMSO complex precursor solution and 0.465 M isopropanol solution of the methylammonium halide mixture with the molar ratio of CH{sub 3}NH{sub 3}I/CH{sub 3}NH{sub 3}Br=85/15. The perovskite solar cells based on the TiO{sub 2} nanorod array and 560 nm-thickness CH{sub 3}NH{sub 3}PbI{sub 3−x}Br{sub x} absorber layer exhibited the best photoelectric conversion efficiency (PCE) of 15.93%, while the corresponding planar perovskite solar cells without the TiO{sub 2} nanorod array and with 530 nm-thickness CH{sub 3}NH{sub 3}PbI{sub 3−x}Br{sub x} absorber layer gave the best PCE of 12.82% at the relative humidity of 50–54%. - Graphical abstract: The TiO{sub 2} nanorod arrays with the length of 70 nm, the diameter of 20 nm, and the areal density of 1000 µm{sup −2} were prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 60 min. The optimal annealing temperature of TiO{sub 2} nanorod arrays was 450 °C. The perovskite solar cells based on the TiO{sub 2} nanorod array and 560 nm-thickness CH{sub 3}NH{sub 3}PbI{sub 3−x}Br{sub x} absorber layer exhibited the best photoelectric conversion efficiency (PCE) of 15.93% and the average PCE of 13.41±2.52%, while the corresponding planar perovskite solar cells without the TiO{sub 2} nanorod array and with 530 nm-thickness CH{sub 3}NH{sub 3}PbI{sub 3−x}Br{sub x} absorber layer gave the best PCE of 12.82% and the average PCE of 10.54±2.28% at the relative humidity of 50–54%. - Highlights:

  18. Short-length and high-density TiO2 nanorod arrays for the efficient charge separation interface in perovskite solar cells

    Xiao, Guannan; Shi, Chengwu; Zhang, Zhengguo; Li, Nannan; Li, Long

    2017-01-01

    The TiO 2 nanorod arrays with the length of 70 nm, the diameter of 20 nm, and the areal density of 1000 µm −2 were firstly prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 60 min. Over-500 nm-thickness CH 3 NH 3 PbI 3−x Br x absorber layers were successfully obtained by sequential deposition routes using 1.7 M PbI 2 ·DMSO complex precursor solution and 0.465 M isopropanol solution of the methylammonium halide mixture with the molar ratio of CH 3 NH 3 I/CH 3 NH 3 Br=85/15. The perovskite solar cells based on the TiO 2 nanorod array and 560 nm-thickness CH 3 NH 3 PbI 3−x Br x absorber layer exhibited the best photoelectric conversion efficiency (PCE) of 15.93%, while the corresponding planar perovskite solar cells without the TiO 2 nanorod array and with 530 nm-thickness CH 3 NH 3 PbI 3−x Br x absorber layer gave the best PCE of 12.82% at the relative humidity of 50–54%. - Graphical abstract: The TiO 2 nanorod arrays with the length of 70 nm, the diameter of 20 nm, and the areal density of 1000 µm −2 were prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 60 min. The optimal annealing temperature of TiO 2 nanorod arrays was 450 °C. The perovskite solar cells based on the TiO 2 nanorod array and 560 nm-thickness CH 3 NH 3 PbI 3−x Br x absorber layer exhibited the best photoelectric conversion efficiency (PCE) of 15.93% and the average PCE of 13.41±2.52%, while the corresponding planar perovskite solar cells without the TiO 2 nanorod array and with 530 nm-thickness CH 3 NH 3 PbI 3−x Br x absorber layer gave the best PCE of 12.82% and the average PCE of 10.54±2.28% at the relative humidity of 50–54%. - Highlights: • Preparation of TiO 2 nanorod array with length of 70 nm and density of 1000 µm −2 . • Influence of annealing temperatures on the -OH content of Ti

  19. Effect of Different HTM Layers and Electrical Parameters on ZnO Nanorod-Based Lead-Free Perovskite Solar Cell for High-Efficiency Performance

    Farhana Anwar

    2017-01-01

    Full Text Available Simulation has been done using SCAPS-1D to examine the efficiency of CH3NH3SnI3-based solar cells including various HTM layers such as spiro-OMeTAD, Cu2O, and CuSCN. ZnO nanorod array has been considered as an ETM layer. Device parameters such as thickness of the CH3NH3SnI3 layer, defect density of interfaces, density of states, and metal work function were studied. For optimum parameters of all three structures, efficiency of 20.21%, 20.23%, and 18.34% has been achieved for spiro-OMeTAD, Cu2O, and CuSCN, respectively. From the simulations, an alternative lead-free perovskite solar cell is introduced with the CH3NH3SnI3 absorber layer, ZnO nanorod ETM layer, and Cu2O HTM layer.

  20. Highly efficient photocatalytic conversion of solar energy to hydrogen by WO3/BiVO4 core-shell heterojunction nanorods

    Kosar, Sonya; Pihosh, Yuriy; Bekarevich, Raman; Mitsuishi, Kazutaka; Mawatari, Kazuma; Kazoe, Yutaka; Kitamori, Takehiko; Tosa, Masahiro; Tarasov, Alexey B.; Goodilin, Eugene A.; Struk, Yaroslav M.; Kondo, Michio; Turkevych, Ivan

    2018-04-01

    Photocatalytic splitting of water under solar light has proved itself to be a promising approach toward the utilization of solar energy and the generation of environmentally friendly fuel in a form of hydrogen. In this work, we demonstrate highly efficient solar-to-hydrogen conversion efficiency of 7.7% by photovoltaic-photoelectrochemical (PV-PEC) device based on hybrid MAPbI3 perovskite PV cell and WO3/BiVO4 core-shell nanorods PEC cell tandem that utilizes spectral splitting approach. Although BiVO4 is characterized by intrinsically high recombination rate of photogenerated carriers, this is not an issue for WO3/BiVO4 core-shell nanorods, where highly conductive WO3 cores are combined with extremely thin absorber BiVO4 shell layer. Since the BiVO4 layer is thinner than the characteristic carrier diffusion length, the photogenerated charge carriers are separated at the WO3/BiVO4 heterojunction before their recombination. Also, such architecture provides sufficient optical thickness even for extremely thin BiVO4 layer due to efficient light trapping in the core-shell WO3/BiVO4 nanorods with high aspect ratio. We also demonstrate that the concept of fill factor can be used to compare I-V characteristics of different photoanodes regarding their optimization for PV/PEC tandem devices.

  1. Full coverage of perovskite layer onto ZnO nanorods via a modified sequential two-step deposition method for efficiency enhancement in perovskite solar cells

    Ruankham, Pipat; Wongratanaphisan, Duangmanee; Gardchareon, Atcharawon; Phadungdhitidhada, Surachet; Choopun, Supab; Sagawa, Takashi

    2017-07-01

    Full coverage of perovskite layer onto ZnO nanorod substrates with less pinholes is crucial for achieving high-efficiency perovskite solar cells. In this work, a two-step sequential deposition method is modified to achieve an appropriate property of perovskite (MAPbI3) film. Surface treatment of perovskite layer and its precursor have been systematically performed and their morphologies have been investigated. By pre-wetting of lead iodide (PbI2) and letting it dry before reacting with methylammonium iodide (MAI) provide better coverage of perovskite film onto ZnO nanorod substrate than one without any treatment. An additional MAI deposition followed with toluene drop-casting technique on the perovskite film is also found to increase the coverage and enhance the transformation of PbI2 to MAPbI3. These lead to longer charge carrier lifetime, resulting in an enhanced power conversion efficiency (PCE) from 1.21% to 3.05%. The modified method could been applied to a complex ZnO nanorods/TiO2 nanoparticles substrate. The enhancement in PCE to 3.41% is observed. These imply that our introduced method provides a simple way to obtain the full coverage and better transformation to MAPbI3 phase for enhancement in performances of perovskite solar cells.

  2. CdS nanoparticles/CeO_2 nanorods composite with high-efficiency visible-light-driven photocatalytic activity

    You, Daotong; Pan, Bao; Jiang, Fan; Zhou, Yangen; Su, Wenyue

    2016-01-01

    Graphical abstract: Coupling CdS with CeO_2 can effectively improve the light-harvesting ability of wide-band gap CeO_2 NRs as the photoinduced electrons on the conduction band of CdS are transfered to the conduction band of CeO_2. - Highlights: • Coupling CdS can effectively improve the light-harvesting ability of wide-band gap CeO_2. • CdS/CeO_2 composites show high photocatalytic activity under visible light irradiation. • The mechanism of photocatalytic H_2 evolution over CdS/CeO_2 was proposed. - Abstract: Different mole ratios of CdS nanoparticles (NPs)/CeO_2 nanorods (NRs) composites with effective contacts were synthesized through a two-step hydrothermal method. The crystal phase, microstructure, optical absorption properties, electrochemical properties and photocatalytic H_2 production activity of these composites were investigated. It was concluded that the photogenerated charge carriers in the CdS NPs/CeO_2 NRs composite with a proper mole ratio (1:1) exhibited the longest lifetime and highest separation efficiency, which was responsible for the highest H_2-production rate of 8.4 mmol h"−"1 g"−"1 under visible-light irradiation (λ > 420 nm). The superior photocatalytic H_2 evolution properties are attributed to the transfer of visible-excited electrons of CdS NPs to CeO_2 NRs, which can effectively extend the light absorption range of wide-band gap CeO_2 NRs. This work provides feasible routes to develop visible-light responsive CeO_2-based nanomaterial for efficient solar utilization.

  3. Nickel Nanowire@Porous NiCo2O4 Nanorods Arrays Grown on Nickel Foam as Efficient Pseudocapacitor Electrode

    Houzhao Wan

    2017-12-01

    Full Text Available A three dimensional hierarchical nanostructure composed of nickel nanowires and porous NiCo2O4 nanorods arrays on the surface of nickel foam is successfully fabricated by a facile route. In this structure, the nickel nanowires are used as core materials to support high-pseudocapacitance NiCo2O4 nanorods and construct the well-defined NiCo2O4 nanorods shell/nickel nanowires core hierarchical structure on nickel foam. Benefiting from the participation of nickel nanowires, the nickel nanowire@NiCo2O4/Ni foam electrode shows a high areal specific capacitance (7.4 F cm−2 at 5 mA cm−2, excellent rate capability (88.04% retained at 100 mA cm−2, and good cycling stability (74.08% retained after 1,500 cycles. The superior electrochemical properties made it promising as electrode for supercapacitors.

  4. Light-activated microbubbles around gold nanorods for photoacoustic microsurgery

    Cavigli, Lucia; Centi, Sonia; Lai, Sarah; Borri, Claudia; Micheletti, Filippo; Tortoli, Paolo; Panettieri, Ilaria; Streit, Ingolf; Rossi, Francesca; Ratto, Fulvio; Pini, Roberto

    2018-02-01

    The increasing interest around imaging and microsurgery techniques based on the photoacoustic effect has boosted active research into the development of exogenous contrast agents that may enhance the potential of this innovative approach. In this context, plasmonic particles as gold nanorods are achieving resounding interest, owing to their efficiency of photothermal conversion, intense optical absorbance in the near infrared region, inertness in the body and convenience for conjugation with ligands of molecular targets. On the other hand, the photoinstability of plasmonic particles remains a remarkable obstacle. In particular, gold nanorods easily reshape into nanospheres and so lose their optical absorbance in the near infrared region, under exposure to few-ns-long laser pulses. This issue is attracting much attention and stimulating ad-hoc solutions, such as the addition of rigid shells and the optimization of multiple parameters. In this contribution, we focus on the influence of the shape of gold nanorods on their photothermal behavior and photostability. We describe the photothermal process in the gold nanorods by modeling their optical absorption and consequent temperature dynamics as a function of their aspect ratio (length / diameter). Our results suggest that increasing the aspect ratio does probably not limit the photostability of gold nanorods, while shifting the plasmonic peak towards wavelengths around 1100 nm, which hold more technological interest.

  5. High-efficiency super capacitors based on hetero-structured α-MnO{sub 2} nanorods

    Ghouri, Zafar Khan [Department of BIN Fusion Technology, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Department of Organic materials and Fiber Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Shaheer Akhtar, M. [New & Renewable Energy Material Development Center (NewREC), Chonbuk National University, Jeonbuk (Korea, Republic of); Zahoor, Awan [Department of Chemical Engineering, NED University of Engineering & Technology, University Road, Karachi 75270 (Pakistan); Barakat, Nasser A.M., E-mail: nasser@jbnu.ac.kr [Department of Organic materials and Fiber Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Department of Chemical Engineering, Faculty of Engineering, El-Minia University, El-Minia (Egypt); Han, Weidong [Department of BIN Fusion Technology, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Park, Mira [Department of Organic materials and Fiber Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Pant, Bishweshwar; Saud, Prem Singh; Lee, Cho Hye [Department of BIN Fusion Technology, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Kim, Hak Yong, E-mail: khy@jbnu.ac.kr [Department of BIN Fusion Technology, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

    2015-09-05

    Highlights: • Hetero-structured α-MnO{sub 2} nanorods are prepared by a facile hydrothermal route. • It is applied as active electrode materials for supercapacitor. • A high specific capacitance of 298 Fg{sup −1} with a superior long term cyclic stability is achieved. • Supercapacitor shows high specific capacitance retention 94% after 1000 cycles. - Abstract: Hetero-structured manganese dioxide nanorods with α phase (α-MnO{sub 2}) were prepared by a facile hydrothermal route at low temperature. X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption–desorption measurements were used to characterize the prepared hetero-structured α-MnO{sub 2} nanorods. Supercapacitive performance of the hetero-structured α-MnO{sub 2} nanomaterials as active electrode material was evaluated by cyclic voltammetry (CV) in alkaline medium. The MnO{sub 2} hetero-structure with 2 × 2 tunnels constructed from double chains of octahedral [MnO{sub 6}] structure yield a significantly high specific capacitance of 298 Fg{sup −1} at 5 mV s{sup −1} and demonstrated a superior long term cyclic stability, with specific capacitance retention about 94% after 1000 cycles. The superior supercapacitive performance of the hetero-structured α-MnO{sub 2} electrode is due to its high specific surface area and unique hierarchy architecture which facilitate fast electron and ion transport.

  6. RuO 2 nanoparticles supported on MnO 2 nanorods as high efficient bifunctional electrocatalyst of lithium-oxygen battery

    Xu, Yue-Feng; Chen, Yuan; Xu, Gui-Liang; Zhang, Xiao-Ru; Chen, Zonghai; Li, Jun-Tao; Huang, Ling; Amine, Khalil; Sun, Shi-Gang

    2016-10-01

    RuO2 nanoparticles supported on MnO2 nanorods (denoted as np-RuO2/nr-MnO2) were synthesized via a two-step hydrothermal reaction. SEM and TEM images both illustrated that RuO2 nanoparticles are well dispersed on the surface of MnO2 nanorods in the as-prepared np-RuO2/nr-MnO2 material. Electrochemical results demonstrated that the np-RuO2/nr-MnO2 as oxygen cathode of Li-O-2 batteries could maintain a reversible capacity of 500 mA h g(-1) within 75 cycles at a rate of 50 mA g(-1), and a higher capacity of 4000 mA h g(-1) within 20 cycles at a rate as high as 200 mA g(-1). Moreover, the cell with the np-RuO2/nr-MnO2 catalyst presented much lower voltage polarization (about 0.58 V at a rate of 50 mA g(-1)) than that measured with only MnO2 nanorods during charge/discharge processes. The catalytic property of the np-RuO2/nr-MnO2 and MnO2 nanorods were further compared by conducting studies of using rotating disk electrode (RDE), chronoamperommetry and linear sweep voltammetry. The results illustrated that the np-RuO2/nr-MnO2 exhibited excellent bifunctional electrocatalytic activities towards both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Furthermore, in-situ high-energy X-ray diffraction was employed to trace evolution of species on the np-RuO2/nr-MnO2 cathode during the discharge processes. In-situ XRD patterns demonstrated the formation process of the discharge products that consisted of mainly Li2O2. Ex-situ SEM images were recorded to investigate the morphology and decomposition of the sphere-like Li2O2, which could be observed clearly after discharge process, while are decomposed almost after charge process. The excellent electrochemical performances of the np-RuO2/nr-MnO2 as cathode of Li-O-2 battery could be contributed to the excellent bifunctional electrocatalytic activities for both the ORR and OER, and to the one-dimensional structure which would benefit the diffusion of oxygen and the storage of Li2O2 in the discharge process of

  7. Improvement in the luminous efficiency of MEH-PPV based light emitting diodes using zinc oxide nanorods grown by the electrochemical deposition technique on ITO substrates

    Gupta, Rohini B; Kumar, Jitender; Madhwal, Devinder; Singh, Inderpreet; Nagpal, S; Bhatnagar, P K; Mathur, P C [Material Science Laboratory, Department of Electronic Science, University of Delhi South Campus, New Delhi (India); Kaur, I; Bhardwaj, L M, E-mail: email_rohini@rediffmail.com [Central Scientific Instruments Organization, Sector-30, Chandigarh (India)

    2011-07-01

    Zinc oxide (ZnO) nanorods grown by the electrochemical technique have been used to enhance the luminance of poly[2-methoxy-5-(2'-ethylhexoxy)-1,4-phenylenevinylene] (MEH-PPV)-based polymer light-emitting diodes. The luminance of the device with ZnO nanorods is found to increase by more than two times as compared with the device without ZnO nanorods. The diameter of the nanorods used in device fabrication was {approx}145 nm. The size of the nanorods was estimated from field emission scanning electron microscope images. Optical and structural characterizations of the nanorods were also performed by using absorption, photoluminescence and x-ray diffraction, confirming the formation of ZnO nanorods.

  8. Combination of short-length TiO_2 nanorod arrays and compact PbS quantum-dot thin films for efficient solid-state quantum-dot-sensitized solar cells

    Zhang, Zhengguo; Shi, Chengwu; Chen, Junjun; Xiao, Guannan; Li, Long

    2017-01-01

    Graphical abstract: The TiO_2 nanorod array with the length of 600 nm, the diameter of 20 nm, the areal density of 500 μm"−"2 was successfully prepared. The compact PbS quantum-dot thin film was firstly obtained on the TiO_2 nanorod array by spin-coating-assisted successive ionic layer absorption and reaction with using 1,2-ethanedithiol. The photoelectric conversion efficiency (PCE) of the compact PbS quantum-dot thin film sensitized solar cells achieved 4.10% using spiro-OMeTAD as a hole transporting layer, while the PCE of the PbS quantum-dot sensitized solar cells was only 0.54%. - Highlights: • Preparation of TiO_2 nanorod arrays with the length of 600 nm, diameter of 20 nm. • The compact PbS QD thin film and short-length TiO_2 nanorod array were combined. • EDT addition improved PbS nanoparticle coverage and photovoltaic performance. • The compact PbS QD thin film sensitized solar cell achieved the PCE of 4.10%. - Abstract: Considering the balance of the hole diffusion length and the loading quantity of quantum-dots, the rutile TiO_2 nanorod array with the length of 600 nm, the diameter of 20 nm, and the areal density of 500 μm"−"2 is successfully prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 105 min. The compact PbS quantum-dot thin film on the TiO_2 nanorod array is firstly obtained by the spin-coating-assisted successive ionic layer absorption and reaction with using 1,2-ethanedithiol (EDT). The result reveals that the strong interaction between lead and EDT is very important to control the crystallite size of PbS quantum-dots and obtain the compact PbS quantum-dot thin film on the TiO_2 nanorod array. The all solid-state sensitized solar cell with the combination of the short-length, high-density TiO_2 nanorod array and the compact PbS quantum-dot thin film achieves the photoelectric conversion efficiency of 4.10%, along with an open

  9. Combination of short-length TiO{sub 2} nanorod arrays and compact PbS quantum-dot thin films for efficient solid-state quantum-dot-sensitized solar cells

    Zhang, Zhengguo [School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009 (China); School of Chemistry and Chemical Engineering, Beifang University of Nationalities, Yinchuan 750021 (China); Shi, Chengwu, E-mail: shicw506@foxmail.com [School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009 (China); Chen, Junjun; Xiao, Guannan; Li, Long [School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009 (China)

    2017-07-15

    Graphical abstract: The TiO{sub 2} nanorod array with the length of 600 nm, the diameter of 20 nm, the areal density of 500 μm{sup −2} was successfully prepared. The compact PbS quantum-dot thin film was firstly obtained on the TiO{sub 2} nanorod array by spin-coating-assisted successive ionic layer absorption and reaction with using 1,2-ethanedithiol. The photoelectric conversion efficiency (PCE) of the compact PbS quantum-dot thin film sensitized solar cells achieved 4.10% using spiro-OMeTAD as a hole transporting layer, while the PCE of the PbS quantum-dot sensitized solar cells was only 0.54%. - Highlights: • Preparation of TiO{sub 2} nanorod arrays with the length of 600 nm, diameter of 20 nm. • The compact PbS QD thin film and short-length TiO{sub 2} nanorod array were combined. • EDT addition improved PbS nanoparticle coverage and photovoltaic performance. • The compact PbS QD thin film sensitized solar cell achieved the PCE of 4.10%. - Abstract: Considering the balance of the hole diffusion length and the loading quantity of quantum-dots, the rutile TiO{sub 2} nanorod array with the length of 600 nm, the diameter of 20 nm, and the areal density of 500 μm{sup −2} is successfully prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 105 min. The compact PbS quantum-dot thin film on the TiO{sub 2} nanorod array is firstly obtained by the spin-coating-assisted successive ionic layer absorption and reaction with using 1,2-ethanedithiol (EDT). The result reveals that the strong interaction between lead and EDT is very important to control the crystallite size of PbS quantum-dots and obtain the compact PbS quantum-dot thin film on the TiO{sub 2} nanorod array. The all solid-state sensitized solar cell with the combination of the short-length, high-density TiO{sub 2} nanorod array and the compact PbS quantum-dot thin film achieves the photoelectric conversion

  10. Trade-off between Zr Passivation and Sn Doping on Hematite Nanorod Photoanodes for Efficient Solar Water Oxidation: Effects of a ZrO2 Underlayer and FTO Deformation.

    Subramanian, Arunprabaharan; Annamalai, Alagappan; Lee, Hyun Hwi; Choi, Sun Hee; Ryu, Jungho; Park, Jung Hee; Jang, Jum Suk

    2016-08-03

    Herein we report the influence of a ZrO2 underlayer on the PEC (photoelectrochemical) behavior of hematite nanorod photoanodes for efficient solar water splitting. Particular attention was given to the cathodic shift in onset potential and photocurrent enhancement. Akaganite (β-FeOOH) nanorods were grown on ZrO2-coated FTO (fluorine-doped tin oxide) substrates. Sintering at 800 °C transformed akaganite to the hematite (α-Fe2O3) phase and induced Sn diffusion into the crystal structure of hematite nanorods from the FTO substrates and surface migration, shallow doping of Zr atoms from the ZrO2 underlayer. The ZrO2 underlayer-treated photoanode showed better water oxidation performance compared to the pristine (α-Fe2O3) photoanode. A cathodic shift in the onset potential and photocurrent enhancement was achieved by surface passivation and shallow doping of Zr from the ZrO2 underlayer, along with Sn doping from the FTO substrate to the crystal lattice of hematite nanorods. The Zr based hematite nanorod photoanode achieved 1 mA/cm(2) at 1.23 VRHE with a low turn-on voltage of 0.80 VRHE. Sn doping and Zr passivation, as well as shallow doping, were confirmed by XPS, Iph, and M-S plot analyses. Electrochemical impedance spectroscopy revealed that the presence of a ZrO2 underlayer decreased the deformation of FTO substrate, improved electron transfer at the hematite/FTO interface and increased charge-transfer resistance at the electrolyte/hematite interface. This is the first systematic investigation of the effects of Zr passivation, shallow doping, and Sn doping on hematite nanorod photoanodes through application of a ZrO2 underlayer on the FTO substrate.

  11. Efficiency Enhancement of Dye-Sensitized Solar Cells’ Performance with ZnO Nanorods Grown by Low-Temperature Hydrothermal Reaction

    Fang-I Lai

    2015-12-01

    Full Text Available In this study, aligned zinc oxide (ZnO nanorods (NRs with various lengths (1.5–5 µm were deposited on ZnO:Al (AZO-coated glass substrates by using a solution phase deposition method; these NRs were prepared for application as working electrodes to increase the photovoltaic conversion efficiency of solar cells. The results were observed in detail by using X-ray diffraction, field-emission scanning electron microscopy, UV-visible spectrophotometry, electrochemical impedance spectroscopy, incident photo-to-current conversion efficiency, and solar simulation. The results indicated that when the lengths of the ZnO NRs increased, the adsorption of D-719 dyes through the ZnO NRs increased along with enhancing the short-circuit photocurrent and open-circuit voltage of the cell. An optimal power conversion efficiency of 0.64% was obtained in a dye-sensitized solar cell (DSSC containing the ZnO NR with a length of 5 µm. The objective of this study was to facilitate the development of a ZnO-based DSSC.

  12. Efficient Donor Impurities in ZnO Nanorods by Polyethylene Glycol for Enhanced Optical and Glutamate Sensing Properties

    Sami Elhag

    2016-02-01

    Full Text Available In this paper, we show that the possibility of using polyethylene glycol (EG as a hydrogen source and it is used to assist the hydrothermal synthesis of ZnO nanorods (ZNRs. EG doping in ZNRs has been found to significantly improve their optical and chemical sensing characteristics toward glutamate. The EG was found to have no role on the structural properties of the ZNRs. However, the x-ray photoelectron spectroscopy (XPS suggests that the EG could induce donor impurities effect in ZnO. Photoluminescence (PL and UV-Vis. spectra demonstrated this doping effect. Mott-Schottky analysis at the ZNRs/electrolyte interface was used to investigate the charge density for the doped ZNRs and showed comparable dependence on the used amount of EG. Moreover, the doped ZNRs were used in potentiometric measurements for glutamate for a range from 10−6 M to 10−3 M and the potential response of the sensor electrode was linear with a slope of 91.15 mV/decade. The wide range and high sensitivity of the modified ZNRs based glutamate biosensor is attributed to the doping effect on the ZNRs that is dictated by the EG along with the high surface area-to-volume ratio. The findings in the present study suggest new avenues to control the growth of n-ZnO nanostructures and enhance the performance of their sensing devices.

  13. Efficient Donor Impurities in ZnO Nanorods by Polyethylene Glycol for Enhanced Optical and Glutamate Sensing Properties.

    Elhag, Sami; Khun, Kimleang; Khranovskyy, Volodymyr; Liu, Xianjie; Willander, Magnus; Nur, Omer

    2016-02-06

    In this paper, we show that the possibility of using polyethylene glycol (EG) as a hydrogen source and it is used to assist the hydrothermal synthesis of ZnO nanorods (ZNRs). EG doping in ZNRs has been found to significantly improve their optical and chemical sensing characteristics toward glutamate. The EG was found to have no role on the structural properties of the ZNRs. However, the x-ray photoelectron spectroscopy (XPS) suggests that the EG could induce donor impurities effect in ZnO. Photoluminescence (PL) and UV-Vis. spectra demonstrated this doping effect. Mott-Schottky analysis at the ZNRs/electrolyte interface was used to investigate the charge density for the doped ZNRs and showed comparable dependence on the used amount of EG. Moreover, the doped ZNRs were used in potentiometric measurements for glutamate for a range from 10(-6) M to 10(-3) M and the potential response of the sensor electrode was linear with a slope of 91.15 mV/decade. The wide range and high sensitivity of the modified ZNRs based glutamate biosensor is attributed to the doping effect on the ZNRs that is dictated by the EG along with the high surface area-to-volume ratio. The findings in the present study suggest new avenues to control the growth of n-ZnO nanostructures and enhance the performance of their sensing devices.

  14. A dielectric barrier discharge (DBD) plasma reactor: an efficient tool to prepare novel RuO2 nanorods

    Ananth, Antony; Gandhi, Mani Sanjeeva; Mok, Young Sun

    2013-01-01

    One-dimensional (1D) nanostructured materials have attracted a great deal of interest owing to their potential applications in various industries. Due to the limitations and cost associated with conventional low-pressure plasma systems, atmospheric-pressure plasma techniques such as dielectric barrier discharges (DBDs) are investigated as an alternative approach for inducing specific chemical reactions. RuO 2 nanomaterials are widely used as supercapacitor electrodes, in field-emission devices and for catalytic applications. In such applications, size and shape dependent properties of nanomaterials play critical roles in improving the performance. In this paper, an attempt is made to prepare 1D RuO 2 nanostructured materials using a DBD plasma. It is reported here that the composition of feed gas is an important factor in determining the final morphology. For example, an Ar + H 2 plasma yields aggregated RuO 2 nanostructures, whereas ‘nanopillar’ and ‘nanorod’ morphologies are obtained when using Ar + O 2 and Ar, respectively. Possible mechanisms behind the morphological differences are elucidated on the basis of the temperature variations inside the plasma reactor and the chemistry of the gaseous reactive species. The application of a DBD plasma to the synthesis of RuO 2 nanorods is reported for the first time in this paper. (paper)

  15. Graphene deposited onto aligned zinc oxide nanorods as an efficient coating for headspace solid-phase microextraction of gasoline fractions from oil samples.

    Wen, Congying; Li, Mengmeng; Li, Wangbo; Li, Zizhou; Duan, Wei; Li, Yulong; Zhou, Jie; Li, Xiyou; Zeng, Jingbin

    2017-12-29

    The content of gasoline fraction in oil samples is not only an important indicator of oil quality, but also an indispensable fundamental data for oil refining and processing. Before its determination, efficient preconcentration and separation of gasoline fractions from complicated matrices is essential. In this work, a thin layer of graphene (G) was deposited onto oriented ZnO nanorods (ZNRs) as a SPME coating. By this approach, the surface area of G was greatly enhanced by the aligned ZNRs, and the surface polarity of ZNRs was changed from polar to less polar, which were both beneficial for the extraction of gasoline fractions. In addition, the ZNRs were well protected by the mechanically and chemically stable G, making the coating highly durable for use. With headspace SPME (HS-SPME) mode, the G/ZNRs coating can effectively extract gasoline fractions from various oil samples, whose extraction efficiency achieved 1.5-5.4 and 2.1-8.2 times higher than those of a G and commercial 7-μm PDMS coating respectively. Coupled with GC-FID, the developed method is sensitive, simple, cost effective and easily accessible for the analysis of gasoline fractions. Moreover, the method is also feasible for the detection of gasoline markers in simulated oil-polluted water, which provides an option for the monitoring of oil spill accident. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. CdS Nanoparticle-Modified α-Fe2O3/TiO2 Nanorod Array Photoanode for Efficient Photoelectrochemical Water Oxidation.

    Yin, Ruiyang; Liu, Mingyang; Tang, Rui; Yin, Longwei

    2017-09-02

    In this work, we demonstrate a facile successive ionic layer adsorption and reaction process accompanied by hydrothermal method to synthesize CdS nanoparticle-modified α-Fe 2 O 3 /TiO 2 nanorod array for efficient photoelectrochemical (PEC) water oxidation. By integrating CdS/α-Fe 2 O 3 /TiO 2 ternary system, light absorption ability of the photoanode can be effectively improved with an obviously broadened optical-response to visible light region, greatly facilitates the separation of photogenerated carriers, giving rise to the enhancement of PEC water oxidation performance. Importantly, for the designed abnormal type-II heterostructure between Fe 2 O 3 /TiO 2 , the conduction band position of Fe 2 O 3 is higher than that of TiO 2 , the photogenerated electrons from Fe 2 O 3 will rapidly recombine with the photogenerated holes from TiO 2 , thus leads to an efficient separation of photogenerated electrons from Fe 2 O 3 /holes from TiO 2 at the Fe 2 O 3 /TiO 2 interface, greatly improving the separation efficiency of photogenerated holes within Fe 2 O 3 and enhances the photogenerated electron injection efficiency in TiO 2 . Working as the photoanodes of PEC water oxidation, CdS/α-Fe 2 O 3 /TiO 2 heterostucture electrode exhibits improved photocurrent density of 0.62 mA cm - 2 at 1.23 V vs. reversible hydrogen electrode (RHE) in alkaline electrolyte, with an obviously negatively shifted onset potential of 80 mV. This work provides promising methods to enhance the PEC water oxidation performance of the TiO 2 -based heterostructure photoanodes.

  17. Embedded vertically aligned cadmium telluride nanorod arrays grown by one-step electrodeposition for enhanced energy conversion efficiency in three-dimensional nanostructured solar cells.

    Wang, Jun; Liu, Shurong; Mu, Yannan; Liu, Li; A, Runa; Yang, Jiandong; Zhu, Guijie; Meng, Xianwei; Fu, Wuyou; Yang, Haibin

    2017-11-01

    Vertically aligned CdTe nanorods (NRs) arrays are successfully grown by a simple one-step and template-free electrodeposition method, and then embedded in the CdS window layer to form a novel three-dimensional (3D) heterostructure on flexible substrates. The parameters of electrodeposition such as deposition potential and pH of the solution are varied to analyze their important role in the formation of high quality CdTe NRs arrays. The photovoltaic conversion efficiency of the solar cell based on the 3D heterojunction structure is studied in detail. In comparison with the standard planar heterojunction solar cell, the 3D heterojunction solar cell exhibits better photovoltaic performance, which can be attributed to its enhanced optical absorption ability, increased heterojunction area and improved charge carrier transport. The better photoelectric property of the 3D heterojunction solar cell suggests great application potential in thin film solar cells, and the simple electrodeposition process represents a promising technique for large-scale fabrication of other nanostructured solar energy conversion devices. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Photocatalytic paper using zinc oxide nanorods

    Baruah, Sunandan; Jaisai, Mayuree; Imani, Reza; Nazhad, Mousa M; Dutta, Joydeep

    2010-01-01

    Zinc oxide (ZnO) nanorods were grown on a paper support prepared from soft wood pulp. The photocatalytic activity of a sheet of paper with ZnO nanorods embedded in its porous matrix has been studied. ZnO nanorods were firmly attached to cellulose fibers and the photocatalytic paper samples were reused several times with nominal decrease in efficiency. Photodegradation of up to 93% was observed for methylene blue in the presence of paper filled with ZnO nanorods upon irradiation with visible light at 963 Wm -2 for 120 min. Under similar conditions, photodegradation of approximately 35% was observed for methyl orange. Antibacterial tests revealed that the photocatalytic paper inhibits the growth of Escherichia coli under room lighting conditions.

  19. GaN based nanorods for solid state lighting

    Li Shunfeng; Waag, Andreas [Institute of Semiconductor Technology, Braunschweig University of Technology, 38106 Braunschweig (Germany)

    2012-04-01

    In recent years, GaN nanorods are emerging as a very promising novel route toward devices for nano-optoelectronics and nano-photonics. In particular, core-shell light emitting devices are thought to be a breakthrough development in solid state lighting, nanorod based LEDs have many potential advantages as compared to their 2 D thin film counterparts. In this paper, we review the recent developments of GaN nanorod growth, characterization, and related device applications based on GaN nanorods. The initial work on GaN nanorod growth focused on catalyst-assisted and catalyst-free statistical growth. The growth condition and growth mechanisms were extensively investigated and discussed. Doping of GaN nanorods, especially p-doping, was found to significantly influence the morphology of GaN nanorods. The large surface of 3 D GaN nanorods induces new optical and electrical properties, which normally can be neglected in layered structures. Recently, more controlled selective area growth of GaN nanorods was realized using patterned substrates both by metalorganic chemical vapor deposition (MOCVD) and by molecular beam epitaxy (MBE). Advanced structures, for example, photonic crystals and DBRs are meanwhile integrated in GaN nanorod structures. Based on the work of growth and characterization of GaN nanorods, GaN nanoLEDs were reported by several groups with different growth and processing methods. Core/shell nanoLED structures were also demonstrated, which could be potentially useful for future high efficient LED structures. In this paper, we will discuss recent developments in GaN nanorod technology, focusing on the potential advantages, but also discussing problems and open questions, which may impose obstacles during the future development of a GaN nanorod based LED technology.

  20. Controllable hydrothermal synthesis of rutile TiO2 hollow nanorod arrays on TiCl4 pretreated Ti foil for DSSC application

    Xi, Min; Zhang, Yulan; Long, Lizhen; Li, Xinjun

    2014-01-01

    Rutile TiO 2 nanorod arrays (TNRs) were achieved by hydrothermal process on TiCl 4 pretreated Ti foil. Subsequently, TNRs were hydrothermally etched in HCl solution to form hollow TiO 2 nanorod arrays (H-TNRs). The TiCl 4 pretreatment plays key roles in enhancement of Ti foil corrosion resistance ability and crystal nucleation introduction for TNRs growth. TNRs with desired morphology can be obtained by controlling TiCl 4 concentration and the amount of tetrabutyl titanate (TTB) accordingly. TNRs with the length of ∼1.5 μm and diameter of ∼200 nm, obtained on 0.15 M TiCl 4 pretreated Ti foil with 0.6 mL TTB, exhibits relatively higher photocurrent. The increased pore volume of the H-TNRs has contributed to the increased surface area which is benefit for Dye-Sensitized Solar Cells (DSSC) application. And the 180 °C-H-TNRs photoanode obtained from the 0.15-TiCl 4 -TNRs sample demonstrated 128.9% enhancement of photoelectric efficiency of DSSC compared to that of the original TNR photoanode. - Graphical abstract: Rutile hollow TiO 2 nanorod array photoanode obtained from original TiO 2 nanorod array photoanode by hydrothermal etching demonstrates enhanced photoelectric efficiency of DSSC. - Highlights: • TiO 2 nanorods are prepared via hydrothermal process on TiCl 4 -pretreated Ti foil. • Hollow TiO 2 nanorods are obtained by hydrothermal etching of TiO 2 nanorods. • TiCl 4 pretreatment plays a key role in protecting Ti foil from chemical corrosion. • Hollow TiO 2 nanorods photoanode shows enhanced photoelectric efficiency for DSSC

  1. Controllable hydrothermal synthesis of rutile TiO{sub 2} hollow nanorod arrays on TiCl{sub 4} pretreated Ti foil for DSSC application

    Xi, Min [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); Zhang, Yulan; Long, Lizhen [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Xinjun, E-mail: lixj@ms.giec.ac.cn [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2014-11-15

    Rutile TiO{sub 2} nanorod arrays (TNRs) were achieved by hydrothermal process on TiCl{sub 4} pretreated Ti foil. Subsequently, TNRs were hydrothermally etched in HCl solution to form hollow TiO{sub 2} nanorod arrays (H-TNRs). The TiCl{sub 4} pretreatment plays key roles in enhancement of Ti foil corrosion resistance ability and crystal nucleation introduction for TNRs growth. TNRs with desired morphology can be obtained by controlling TiCl{sub 4} concentration and the amount of tetrabutyl titanate (TTB) accordingly. TNRs with the length of ∼1.5 μm and diameter of ∼200 nm, obtained on 0.15 M TiCl{sub 4} pretreated Ti foil with 0.6 mL TTB, exhibits relatively higher photocurrent. The increased pore volume of the H-TNRs has contributed to the increased surface area which is benefit for Dye-Sensitized Solar Cells (DSSC) application. And the 180 °C-H-TNRs photoanode obtained from the 0.15-TiCl{sub 4}-TNRs sample demonstrated 128.9% enhancement of photoelectric efficiency of DSSC compared to that of the original TNR photoanode. - Graphical abstract: Rutile hollow TiO{sub 2} nanorod array photoanode obtained from original TiO{sub 2} nanorod array photoanode by hydrothermal etching demonstrates enhanced photoelectric efficiency of DSSC. - Highlights: • TiO{sub 2} nanorods are prepared via hydrothermal process on TiCl{sub 4}-pretreated Ti foil. • Hollow TiO{sub 2} nanorods are obtained by hydrothermal etching of TiO{sub 2} nanorods. • TiCl{sub 4} pretreatment plays a key role in protecting Ti foil from chemical corrosion. • Hollow TiO{sub 2} nanorods photoanode shows enhanced photoelectric efficiency for DSSC.

  2. Preparation and characterization of dye-sensitized TiO{sub 2} nanorod solar cells

    Meng, Lijian, E-mail: ljm@isep.ipp.pt [Departamento de Física, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto (Portugal); Centro de Física, Universidade do Minho, 4800-058 Guimarães (Portugal); Chen, Hong [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, fine Mechanics and Physics of Chinese Academy of Science, Changchun 130033 (China); Li, Can [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023,China (China); Santos, M.P. dos [CEFITEC, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Departamento de Física, Escola de Ciências e Tecnologia, Universidade de Évora (Portugal)

    2015-02-27

    TiO{sub 2} nanorods were prepared by DC reactive magnetron sputtering technique and applied to dye-sensitized solar cells (DSSCs). The length of the TiO{sub 2} nanorods was varied from 1 μm to 6 μm. The scanning electron microscopy images show that the nanorods are perpendicular to the substrate. Both the X-ray diffraction patterns and Raman scattering results show that the nanorods have an anatase phase; no other phase has been observed. (101) and the (220) diffraction peaks have been observed for the TiO{sub 2} nanorods. The (101) diffraction peak intensity remained constant despite the increase of nanorod length, while the intensity of the (220) diffraction peak increased almost linearly with the nanorod length. These nanorods were used as the working electrodes in DSSCs and the effect of the nanorod length on the conversion efficiency has been studied. An optimum photoelectric conversion efficiency of 4.8% has been achieved for 4 μm length nanorods. - Highlights: • [110] oriented TiO{sub 2} nanorods were deposited on ITO substrate by dc reactive magnetron sputtering. • The structural properties of these nanorods have been studied. • The (110) texture is dominated by strain energy minimization. • DSSCs were assembled using these nanorods as electrode.

  3. Cadmium Sulphide Nanorods: Synthesis, Characterization and their Photocatalytic Activity

    Giribabu, Krishnamoorthy; Suresh, Ranganathan; Manigandan, Ramadoss; Vijayaraj, Arunachalam; Prabu, Raju; Narayanan, Vengidusamy

    2012-01-01

    Cadmium sulphide (CdS) nanorods were prepared by a single precursor thermal decomposition (SPTD) method. The formation of CdS nanorods and their structure, morphology and elemental composition were studied by means of FT-IR, XRD, FE-SEM, HR-TEM and EDAX analysis. Photoluminescence (PL) and lifetime measurements were recorded to study the luminescence properties of the material. The PL spectrum of the CdS nanorods showed one broad peak and four shoulders and the cause for this emission was discussed. The PL emissions from the band edge and deep trap state of the CdS nanorods were studied by lifetime measurements. Further, the synthesized CdS nanorods showed an increase in efficiency of photocatalytic degradation of methylene blue (MB) and rhodamine B (RhB). The increase in the photocatalytic activity was attributed to the mixed phase of the CdS nanorods

  4. Cadmium Sulphide Nanorods: Synthesis, Characterization and their Photocatalytic Activity

    Giribabu, Krishnamoorthy; Suresh, Ranganathan; Manigandan, Ramadoss; Vijayaraj, Arunachalam; Prabu, Raju; Narayanan, Vengidusamy [Univ. of Madras, Madras (India)

    2012-09-15

    Cadmium sulphide (CdS) nanorods were prepared by a single precursor thermal decomposition (SPTD) method. The formation of CdS nanorods and their structure, morphology and elemental composition were studied by means of FT-IR, XRD, FE-SEM, HR-TEM and EDAX analysis. Photoluminescence (PL) and lifetime measurements were recorded to study the luminescence properties of the material. The PL spectrum of the CdS nanorods showed one broad peak and four shoulders and the cause for this emission was discussed. The PL emissions from the band edge and deep trap state of the CdS nanorods were studied by lifetime measurements. Further, the synthesized CdS nanorods showed an increase in efficiency of photocatalytic degradation of methylene blue (MB) and rhodamine B (RhB). The increase in the photocatalytic activity was attributed to the mixed phase of the CdS nanorods.

  5. Cobalt phosphate-modified barium-doped tantalum nitride nanorod photoanode with 1.5% solar energy conversion efficiency

    Li, Yanbo; Zhang, Li; Torres-Pardo, Almudena; Gonzá lez- Calbet, José Marí a Gonzá lez; Ma, Yanhang; Oleynikov, Peter; Terasaki, Osamu; Asahina, Shunsuke; Shima, Masahide; Cha, Dong Kyu; Zhao, Lan; Takanabe, Kazuhiro; Kubota, Jun; Domen, Kazunari

    2013-01-01

    conversion efficiency of 1.5%, which is more than three times higher than that of state-of-the-art single-photon photoanodes. Further, stoichiometric oxygen and hydrogen are stably produced on the photoanode and the counter electrode with Faraday efficiency

  6. CdS nanoparticles/CeO{sub 2} nanorods composite with high-efficiency visible-light-driven photocatalytic activity

    You, Daotong; Pan, Bao; Jiang, Fan; Zhou, Yangen; Su, Wenyue, E-mail: suweny@fzu.edu.cn

    2016-02-15

    Graphical abstract: Coupling CdS with CeO{sub 2} can effectively improve the light-harvesting ability of wide-band gap CeO{sub 2} NRs as the photoinduced electrons on the conduction band of CdS are transfered to the conduction band of CeO{sub 2}. - Highlights: • Coupling CdS can effectively improve the light-harvesting ability of wide-band gap CeO{sub 2}. • CdS/CeO{sub 2} composites show high photocatalytic activity under visible light irradiation. • The mechanism of photocatalytic H{sub 2} evolution over CdS/CeO{sub 2} was proposed. - Abstract: Different mole ratios of CdS nanoparticles (NPs)/CeO{sub 2} nanorods (NRs) composites with effective contacts were synthesized through a two-step hydrothermal method. The crystal phase, microstructure, optical absorption properties, electrochemical properties and photocatalytic H{sub 2} production activity of these composites were investigated. It was concluded that the photogenerated charge carriers in the CdS NPs/CeO{sub 2} NRs composite with a proper mole ratio (1:1) exhibited the longest lifetime and highest separation efficiency, which was responsible for the highest H{sub 2}-production rate of 8.4 mmol h{sup −1} g{sup −1} under visible-light irradiation (λ > 420 nm). The superior photocatalytic H{sub 2} evolution properties are attributed to the transfer of visible-excited electrons of CdS NPs to CeO{sub 2} NRs, which can effectively extend the light absorption range of wide-band gap CeO{sub 2} NRs. This work provides feasible routes to develop visible-light responsive CeO{sub 2}-based nanomaterial for efficient solar utilization.

  7. Ultrafast carrier dynamics unravel role of surface ligands and metal domain size on the photocatalytic hydrogen evolution efficiency of Au-tipped CdS nanorods: an ultrafast transient absorption spectroscopy study

    Ben-Shahar, Yuval; Kriegel, Ilka; Scotognella, Francesco; Waiskopf, Nir; Dal Conte, Stefano; Moretti, Luca; Cerullo, Giulio; Rabani, Eran; Banin, Uri

    2017-02-01

    Semiconductor-metal hybrid nanostructures are interesting materials for photocatalysis. Their tunable properties offer a highly controllable platform to design light-induced charge separation, a key to their function in photocatalytic water splitting. Hydrogen evolution quantum yields are influenced by factors as size, shape, material and morphology of the system, additionally the surface coating or the metal domain size play a dominant role. In this paper we present a study on a well-defined model system of Au-tipped CdS nanorods. We use transient absorption spectroscopy to get insights into the charge carrier dynamics after photoexcitation of the bandgap of CdS nanorods. The study of charge transfer processes combined with the hydrogen evolution efficiency unravels the effects of surface coating and the gold tip size on the photocatalytic efficiency. Differences in efficiency with various surface ligands are primarily ascribed to the effects of surface passivation. Surface trapping of charge carriers is competing with effective charge separation, a prerequisite for photocatalysis, leading to the observed lower hydrogen production quantum yields. Interestingly, non-monotonic hydrogen evolution efficiency with size of the gold tip is observed, resulting in an optimal metal domain size for the most efficient photocatalysis. These results are explained by the sizedependent interplay of the metal domain charging and the relative band-alignments. Taken together our findings are of major importance for the potential application of hybrid nanoparticles as photocatalysts.

  8. Cobalt phosphate-modified barium-doped tantalum nitride nanorod photoanode with 1.5% solar energy conversion efficiency

    Li, Yanbo

    2013-10-03

    Spurred by the decreased availability of fossil fuels and global warming, the idea of converting solar energy into clean fuels has been widely recognized. Hydrogen produced by photoelectrochemical water splitting using sunlight could provide a carbon dioxide lean fuel as an alternative to fossil fuels. A major challenge in photoelectrochemical water splitting is to develop an efficient photoanode that can stably oxidize water into oxygen. Here we report an efficient and stable photoanode that couples an active barium-doped tantalum nitride nanostructure with a stable cobalt phosphate co-catalyst. The effect of barium doping on the photoelectrochemical activity of the photoanode is investigated. The photoanode yields a maximum solar energy conversion efficiency of 1.5%, which is more than three times higher than that of state-of-the-art single-photon photoanodes. Further, stoichiometric oxygen and hydrogen are stably produced on the photoanode and the counter electrode with Faraday efficiency of almost unity for 100 min. © 2013 Macmillan Publishers Limited. All rights reserved.

  9. Hierarchical structures consisting of SiO2 nanorods and p-GaN microdomes for efficiently harvesting solar energy for InGaN quantum well photovoltaic cells.

    Ho, Cheng-Han; Lien, Der-Hsien; Chang, Hung-Chih; Lin, Chin-An; Kang, Chen-Fang; Hsing, Meng-Kai; Lai, Kun-Yu; He, Jr-Hau

    2012-12-07

    We experimentally and theoretically demonstrated the hierarchical structure of SiO(2) nanorod arrays/p-GaN microdomes as a light harvesting scheme for InGaN-based multiple quantum well solar cells. The combination of nano- and micro-structures leads to increased internal multiple reflection and provides an intermediate refractive index between air and GaN. Cells with the hierarchical structure exhibit improved short-circuit current densities and fill factors, rendering a 1.47 fold efficiency enhancement as compared to planar cells.

  10. Graded core/shell semiconductor nanorods and nanorod barcodes

    Alivisatos, A. Paul; Scher, Erik C.; Manna, Liberato

    2010-12-14

    Graded core/shell semiconductor nanorods and shaped nanorods are disclosed comprising Group II-VI, Group III-V and Group IV semiconductors and methods of making the same. Also disclosed are nanorod barcodes using core/shell nanorods where the core is a semiconductor or metal material, and with or without a shell. Methods of labeling analytes using the nanorod barcodes are also disclosed.

  11. Fabrication and photovoltaic properties of ZnO nanorods/perovskite solar cells

    Shirahata, Yasuhiro; Tanaike, Kohei; Akiyama, Tsuyoshi; Fujimoto, Kazuya; Suzuki, Atsushi; Balachandran, Jeyadevan; Oku, Takeo, E-mail: oku@mat.usp.ac.jp [Department of Materials Science, The University of Shiga Prefecture, 2500 Hassaka, Hikone, Shiga 522-8533 (Japan)

    2016-02-01

    ZnO nanorods/perovskite solar cells with different lengths of ZnO nanorods were fabricated. The ZnO nanorods were prepared by chemical bath deposition and directly confirmed to be hexagon-shaped nanorods. The lengths of the ZnO nanorads were controlled by deposition condition of ZnO seed layer. Photovoltaic properties of the ZnO nanorods/CH{sub 3}NH{sub 3}PbI{sub 3} solar cells were investigated by measuring current density-voltage characteristics and incident photon to current conversion efficiency. The highest conversion efficiency was obtained in ZnO nanorods/CH{sub 3}NH{sub 3}PbI{sub 3} with the longest ZnO nanorods.

  12. Manganese oxalate nanorods as ballistic modifier for composite solid propellants

    Singh, Supriya [Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273009, U.P. (India); Chawla, Mohit [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi 175005, H.P. (India); Siril, Prem Felix, E-mail: prem@iitmandi.ac.in [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi 175005, H.P. (India); Singh, Gurdip [Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273009, U.P. (India)

    2014-12-10

    Highlights: • Manganese oxalate nanorods were prepared using mild thermal precipitation and aging. • The nanorods were found to be efficient ballistic modifier for solid propellants. • The nanorods sensitized the thermolysis of ammonium perchlorate. • Controlled thermal decomposition of nanorods yielded manganese oxide nanoparticles. • MnO nanoparticles formed insitu in the condensed phase enhance the burning rates. - Abstract: Rod-shaped nanostructures of manganese oxalate (MnC{sub 2}O{sub 4}) were synthesized via mild thermal precipitation and aging process. Chemical composition of the MnC{sub 2}O{sub 4} nanorods was confirmed using Fourier transform infra-red (FTIR) spectroscopy and energy dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) and selected area electron diffraction (SAED) studies revealed the crystal structure. Field emission scanning electron microscopy (FE-SEM) imaging and high resolution transmission electron microscopy (HR-TEM) were employed to study the structural features of the nanorods. The MnC{sub 2}O{sub 4} nanorods were found to be efficient ballistic modifier for the burning rate enhancement of composite solid propellants (CSPs). Thermal analysis using TGA-DSC showed that MnC{sub 2}O{sub 4} nanorods sensitized the thermal decomposition of ammonium perchlorate (AP) and the CSPs. Controlled thermal decomposition of the MnC{sub 2}O{sub 4} nanorods resulted in the formation of managanese oxide nanoparticles with mesoporosity. A plausible mechanism for the burning rate enhancement using MnC{sub 2}O{sub 4} nanorods was proposed.

  13. Enormous enhancement of ZnO nanorod photoluminescence

    Wang, Y.H.; Duan, W.J.; Wu, Z.L.; Zheng, D.; Zhou, X.W.; Zhou, B.Y.; Dai, L.J.; Wang, Y.S.

    2012-01-01

    ZnO nanorod arrays were grown on quartz slices in the aqueous solution of zinc acetate and hexamethylenetetramine at 90 °C. Then ZnO:Mg shells were epitaxially grown on the nanorods to form core/shell structures in the aqueous solution of zinc acetate, magnesium acetate and hexamethylenetetramine at the same temperature. Effects of the shells and UV laser beam irradiation on the crystal structure and photoluminescence properties of ZnO nanorods were studied. ZnO:Mg shells suppress the green emission and enhance the UV emission intensity of the nanorods by 38 times. Enhancement of the UV emission depends on the Mg content in the shells. Short time UV laser beam irradiation could improve ZnO nanorod emission efficiently. The UV emission intensity of ZnO nanorods is enhanced by 71 times by capping and subsequent UV laser beam irradiation. - Highlights: ► ZnO nanorod arrays were grown on quartz slices in solution at 90 °C. ► The nanorods were capped by ZnO:Mg layers to form core/shell structures. ► ZnO:MgO shells suppress the green emission and enhance the UV emission intensity by 38 times. ► The enhancement depends on the Mg content in the shells. ► Exposing the nanorods to 325 laser beam improves the UV emission efficiently. ► Capping and 325 nm laser beam irradiation could enhance the nanorod UV emission intensity by 71 times.

  14. Ranking production units according to marginal efficiency contribution

    Ghiyasi, Mojtaba; Hougaard, Jens Leth

    League tables associated with various forms of service activities from schools to hospitals illustrate the public need for ranking institutions by their productive performance. We present a new method for ranking production units which is based on each units marginal contribution to the technical...

  15. Nickel Nanowire@Porous NiCo{sub 2}O{sub 4} Nanorods Arrays Grown on Nickel Foam as Efficient Pseudocapacitor Electrode

    Wan, Houzhao; Li, Lang; Zhang, Jun; Liu, Xiang; Wang, Hanbin; Wang, Hao, E-mail: nanoguy@126.com [Faculty of Physics and Electronic Science, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Laboratory of Ferro & Piezoelectric Materials and Devices, Hubei University, Wuhan (China)

    2017-12-13

    A three dimensional hierarchical nanostructure composed of nickel nanowires and porous NiCo{sub 2}O{sub 4} nanorods arrays on the surface of nickel foam is successfully fabricated by a facile route. In this structure, the nickel nanowires are used as core materials to support high-pseudocapacitance NiCo{sub 2}O{sub 4} nanorods and construct the well-defined NiCo{sub 2}O{sub 4} nanorods shell/nickel nanowires core hierarchical structure on nickel foam. Benefiting from the participation of nickel nanowires, the nickel nanowire@NiCo{sub 2}O{sub 4}/Ni foam electrode shows a high areal specific capacitance (7.4 F cm{sup −2} at 5 mA cm{sup −2}), excellent rate capability (88.04% retained at 100 mA cm{sup −2}), and good cycling stability (74.08% retained after 1,500 cycles). The superior electrochemical properties made it promising as electrode for supercapacitors.

  16. Performance of healthcare organizations: contributing variables to efficiency and quality

    Albuquerque, Isabel Garcia da Fonseca e Faro de

    2018-01-01

    The transition from volume-based healthcare to value-based healthcare has been the major challenge of National Health Systems. Nevertheless, some variables that might contribute to bring together healthcare professionals and healthcare challenges have been overlooked. Study A, the first of three studies, conducted in a primary healthcare setting, revealed that perceived and objective organizational performance is predicted by sense of community, which simultaneously mediates the relationship ...

  17. Asymmetry in Signal Oscillations Contributes to Efficiency of Periodic Systems.

    Bae, Seul-A; Acevedo, Alison; Androulakis, Ioannis P

    2016-01-01

    Oscillations are an important feature of cellular signaling that result from complex combinations of positive- and negative-feedback loops. The encoding and decoding mechanisms of oscillations based on amplitude and frequency have been extensively discussed in the literature in the context of intercellular and intracellular signaling. However, the fundamental questions of whether and how oscillatory signals offer any competitive advantages-and, if so, what-have not been fully answered. We investigated established oscillatory mechanisms and designed a study to analyze the oscillatory characteristics of signaling molecules and system output in an effort to answer these questions. Two classic oscillators, Goodwin and PER, were selected as the model systems, and corresponding no-feedback models were created for each oscillator to discover the advantage of oscillating signals. Through simulating the original oscillators and the matching no-feedback models, we show that oscillating systems have the capability to achieve better resource-to-output efficiency, and we identify oscillatory characteristics that lead to improved efficiency.

  18. Engineering Gold Nanorod-Based Plasmonic Nanocrystals for Optical Applications

    Huang, Jianfeng

    2015-09-01

    Plasmonic nanocrystals have a unique ability to support localized surface plasmon resonances and exhibit rich and intriguing optical properties. Engineering plasmonic nanocrystals can maximize their potentials for specific applications. In this dissertation, we developed three unprecedented Au nanorod-based plasmonic nanocrystals through rational design of the crystal shape and/or composition, and successfully demonstrated their applications in light condensation, photothermal conversion, and surface-enhanced Raman spectroscopy (SERS). The “Au nanorod-Au nanosphere dimer” nanocrystal was synthesized via the ligand-induced asymmetric growth of a Au nanosphere on a Au nanorod. This dimeric nanostructure features an extraordinary broadband optical absorption in the range of 400‒1400nm, and it proved to be an ideal black-body material for light condensation and an efficient solar-light harvester for photothermal conversion. The “Au nanorod (core) @ AuAg alloy (shell)” nanocrystal was built through the epitaxial growth of homogeneously alloyed AuAg shells on Au nanorods by precisely controlled synthesis. The resulting core-shell structured, bimetallic nanorods integrate the merits of the AuAg alloy with the advantages of anisotropic nanorods, exhibiting strong, stable and tunable surface plasmon resonances that are essential for SERS applications in a corrosive environment. The “high-index faceted Au nanorod (core) @ AuPd alloy (shell)” nanocrystal was produced via site-specific epitaxial growth of AuPd alloyed horns at the ends of Au nanorods. The AuPd alloyed horns are bound with high-index side facets, while the Au nanorod concentrates an intensive electric field at each end. This unique configuration unites highly active catalytic sites with strong SERS sites into a single entity and was demonstrated to be ideal for in situ monitoring of Pd-catalyzed reactions by SERS. The synthetic strategies developed here are promising towards the fabrication of

  19. Enhanced photovoltaic performance of ZnO nanorod-based dye-sensitized solar cells by using Ga doped ZnO seed layer

    Dou, Yuanyao [State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044 (China); Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Wu, Fang, E-mail: fang01234@163.com [State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044 (China); Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Mao, Caiying [Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Fang, Liang, E-mail: lfang@cqu.edu.cn [State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044 (China); Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Guo, Shengchun [Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Zhou, Miao [State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044 (China)

    2015-06-05

    Highlights: • ZnO nanorods were grown on Ga-doped ZnO seed layers using hydrothermal method. • Using the ZnO nanorods as photoanodes for fabricated dye-sensitized solar cells. • The highest η of 1.23% can be achieved in a DSSC with 3 at.% Ga-doped in seeds. • The effects of ZnO seed layers on electron transport properties were investigated. • The enhancement performance of DSSCs contributed to higher dye loading and η{sub cc}. - Abstract: Zinc oxide (ZnO) nanorod arrays were grown on FTO substrates with a Ga-doped ZnO (GZO) seed layer by a hydrothermal method. GZO seed layers were obtained via sol–gel technology with Ga concentration in the range of 0–4 at.%. The dye sensitized solar cells (DSSCs) using ZnO nanorod arrays as the photoanode layers were prepared. The effect of Ga dopant concentrations in ZnO seed layer on the morphology features of ZnO nanorod arrays and the performance of DSSCs were systematically investigated. Results indicate that the average diameter and density of ZnO nanorod arrays decrease with increasing Ga concentration, but their length shows an opposite trend. The photocurrent density–voltage (J–V) characteristics reveal that the DSSCs with GZO seed layer exhibit significantly improved photovoltaic performance. In particular, the highest energy conversion efficiency (η) of 1.23% can be achieved in a DSSC with 3 at.% Ga doping, which is increased by 86.36% compared with that of the undoped DSSC. The external quantum efficiency (EQE) spectra and electrochemical impedance spectroscopy (EIS) were employed to explore the photon-to-electron conversion process in DSSCs. It is demonstrated that the performance enhancement of DSSCs based on GZO seed layer can be attributed to higher amount of dye loading, more efficient electron transportation and better electrons collection efficiency.

  20. Efficient one-pot synthesis of Ag nanoparticles loaded on N-doped multiphase TiO2 hollow nanorod arrays with enhanced photocatalytic activity

    Wu Min; Yang Beifang; Lv Yan; Fu Zhengping; Xu Jiao; Guo Ting; Zhao Yongxun

    2010-01-01

    The simultaneous Ag loaded and N-doped TiO 2 hollow nanorod arrays with various contents of silver (Ag/N-THNAs) were successfully synthesized on glass substrates by one-pot liquid phase deposition (LPD) method using ZnO nanorod arrays as template. The catalysts were characterized by Raman spectrum, field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscope (HRTEM), ultraviolet-vis (UV-vis) absorption spectrum and X-ray photoelectron spectroscopy (XPS). The results suggest that AgNO 3 additive in the precursor solutions not only can promote the anatase-to-rutile phase transition, but also influence the amount of N doping in the samples. The photocatalytic activity of all the samples was evaluated by photodegradation of methylene blue (MB) in aqueous solution. The sample exhibited the highest photocatalytic activity under UV light illumination when the AgNO 3 concentration in the precursor solution was 0.03 M, due to Ag nanoparticles acting as electron sinks; When the AgNO 3 concentration was 0.07 M, the sample performed best under visible light illumination, attributed to the synergetic effects of Ag loading, N doping, and the multiphase structure (anatase/rutile).

  1. Gold nanorods and nanospheroids for enhancing spontaneous emission

    Mohammadi, A [Department of Physics, Persian Gulf University, 75196 Bushehr (Iran, Islamic Republic of); Sandoghdar, V; Agio, M [Laboratory of Physical Chemistry, ETH Zurich, 8093 Zurich (Switzerland)], E-mail: mario.agio@phys.chem.ethz.ch

    2008-10-15

    We compute the radiative decay rate and the quantum efficiency for an emitter coupled to gold nanorods and nanospheroids using the body-of-revolution finite-difference time-domain method. We study these quantities as a function of the nanoparticle aspect ratio and volume, showing that large enhancements can be achieved with realistic parameters. Moreover, we find that nanospheroids exhibit better performances than nanorods for applications in the visible and near-infrared spectral range.

  2. Gold nanorods and nanospheroids for enhancing spontaneous emission

    Mohammadi, A; Sandoghdar, V; Agio, M

    2008-01-01

    We compute the radiative decay rate and the quantum efficiency for an emitter coupled to gold nanorods and nanospheroids using the body-of-revolution finite-difference time-domain method. We study these quantities as a function of the nanoparticle aspect ratio and volume, showing that large enhancements can be achieved with realistic parameters. Moreover, we find that nanospheroids exhibit better performances than nanorods for applications in the visible and near-infrared spectral range.

  3. Efficient Photocatalytic Degradation of Malachite Green in Seawater by the Hybrid of Zinc-Oxide Nanorods Grown on Three-Dimensional (3D Reduced Graphene Oxide(RGO/Ni Foam

    Qing Wang

    2018-06-01

    Full Text Available A hybrid of ZnO nanorods grown onto three-dimensional (3D reduced graphene oxide (RGO@Ni foam (ZnO/RGO@NF is synthesized by a facile hydrothermal method. The as-prepared hybrid material is physically characterized by SEM, XRD, Raman, and X-ray photoelectron spectroscopy (XPS. When the as-prepared 3D hybrid is investigated as a photocatalyst, it demonstrates significant high photocatalytic activity for the degradation of methylene blue (MB, rhodamine (RhB, and mixed MB/RhB as organic dye pollutants. In addition, the practical application and the durability of the as-prepared catalyst to degradation of malachite green (MG in seawater are firstly assessed in a continuous flow system. The catalyst shows a high degradation efficiency and stable photocatalytic activity for 5 h continuous operation, which should be a promising catalyst for the degradation of organic dyes in seawater.

  4. ZnO-nanorod arrays for solar cells with extremely thin sulfidic absorber

    Belaidi, A.; Dittrich, Th.; Kieven, D.; Tornow, J.; Schwarzburg, K.; Kunst, M.; Allsop, N.; Lux-Steiner, M.-Ch. [Hahn-Meitner-Institute, Glienicker Str. 100, D-14109 Berlin (Germany); Gavrilov, S. [Moscow Institute of Electronic Technology, 124 498 Moscow (Russian Federation)

    2009-06-15

    Solar cells with an extremely thin sulfidic absorber have been prepared by spray ion layer gas reaction (ILGAR) of In{sub 2}S{sub 3} on ZnO-nanorod arrays. As transparent hole conductor, CuSCN was deposited on the coated ZnO nanorods by impregnation. Surface photovoltage spectroscopy was applied to characterize states contributing to excess carrier generation and charge separation. The charge-selective contact is formed at the In{sub 2}S{sub 3}/CuSCN interface region the states of which also contribute significantly to the photocurrent. The influence of annealing temperature and annealing time of the In{sub 2}S{sub 3}/CuSCN contact region on the open-circuit potential (V{sub OC}), short-circuit current (I{sub SC}) and fill factor (FF) was studied in detail. For solar cells based on ZnO-nanorod arrays (rod length 1.5 {mu}m), efficiency of 2.8% is obtained at AM1.5. (author)

  5. Physical properties of nanorods

    Krahne, Roman; George, Chandramohan [Istituto Italiano di Tecnologia, Genoa (Italy). Nanostructures; Manna, Liberato [Istituto Italiano di Tecnologia, Genoa (Italy). Nanochemistry; Morello, Giovanni [CNR, Lecce (Italy). Nanoscience Institute; Figuerola, Albert [Barcelona Univ. (Spain). Inst. de Nanociencia i Nanotecnologia; Deka, Sasanka [Delhi Univ. (India). Dept. of Chemistry

    2013-06-01

    Inorganic nanoparticles are among the most investigated objects nowadays, both in fundamental science and in various technical applications. In this book the physical properties of nanowires formed by nanoparticles with elongated shape, i.e. rod-like or wire-like, are described. The transition in the physical properties is analyzed for nanorods and nanowires consisting of spherical and rod-like nanoparticles. The physical properties of nanowires and elongated inorganic nanoparticles are reviewed too. The optical, electrical, magnetic, mechanical and catalytic properties of nanowires consisting of semiconductors, noble and various other metals, metal oxides properties and metal alloys are presented. The applications of nanorods and nanowires are discussed in the book.

  6. Performance Improvement of GaN-Based Flip-Chip White Light-Emitting Diodes with Diffused Nanorod Reflector and with ZnO Nanorod Antireflection Layer

    Hsin-Ying Lee

    2014-01-01

    Full Text Available The GaN-based flip-chip white light-emitting diodes (FCWLEDs with diffused ZnO nanorod reflector and with ZnO nanorod antireflection layer were fabricated. The ZnO nanorod array grown using an aqueous solution method was combined with Al metal to form the diffused ZnO nanorod reflector. It could avoid the blue light emitted out from the Mg-doped GaN layer of the FCWLEDs, which caused more blue light emitted out from the sapphire substrate to pump the phosphor. Moreover, the ZnO nanorod array was utilized as the antireflection layer of the FCWLEDs to reduce the total reflection loss. The light output power and the phosphor conversion efficiency of the FCWLEDs with diffused nanorod reflector and 250 nm long ZnO nanorod antireflection layer were improved from 21.15 mW to 23.90 mW and from 77.6% to 80.1% in comparison with the FCWLEDs with diffused nanorod reflector and without ZnO nanorod antireflection layer, respectively.

  7. Adsorption of Organophosphate Pesticide Dimethoate on Gold Nanospheres and Nanorods

    Tatjana Momić

    2016-01-01

    Full Text Available Organophosphorus pesticide dimethoate was adsorbed onto gold nanospheres and nanorods in aqueous solution using batch technique. Adsorption of dimethoate onto gold nanoparticles was confirmed by UV-Vis spectrophotometry, TEM, AFM, and FTIR analysis. The adsorption of nanospheres resulted in aggregation which was not the case with nanorods. Nanoparticles adsorption features were characterized using Langmuir and Freundlich isotherm models. The Langmuir adsorption isotherm was found to have the best fit to the experimental data for both types of nanoparticles. Adsorption capacity detected for nanospheres is 456 mg/g and for nanorods is 57.1 mg/g. Also, nanoparticles were successfully used for dimethoate removal from spiked drinking water while nanospheres were shown to be more efficient than nanorods.

  8. Solid-state dye-sensitized solar cells based on ZnO nanoparticle and nanorod array hybrid photoanodes

    Sue Hung-Jue

    2011-01-01

    Full Text Available Abstract The effect of ZnO photoanode morphology on the performance of solid-state dye-sensitized solar cells (DSSCs is reported. Four different structures of dye-loaded ZnO layers have been fabricated in conjunction with poly(3-hexylthiophene. A significant improvement in device efficiency with ZnO nanorod arrays as photoanodes has been achieved by filling the interstitial voids of the nanorod arrays with ZnO nanoparticles. The overall power conversion efficiency increases from 0.13% for a nanorod-only device to 0.34% for a device with combined nanoparticles and nanorod arrays. The higher device efficiency in solid-state DSSCs with hybrid nanorod/nanoparticle photoanodes is originated from both large surface area provided by nanoparticles for dye adsorption and efficient charge transport provided by the nanorod arrays to reduce the recombinations of photogenerated carriers.

  9. Fabrication and spectroscopic studies on highly luminescent CdSe/CdS nanorod polymer composites

    Bomm, J.; Büchtemann, A.; Fiore, Angela; Manna, L.; Nelson, J.H.; Hill, D.; van Sark, W.G.J.H.M.

    2010-01-01

    Highly luminescent nanocomposites were prepared by incorporating CdSe/CdS core/shell nanorods into different polymer matrices. The resulting nanocomposites show high transparency of up to 93%. A photoluminescence quantum efficiency of 70% was obtained, with an optimum combination of nanorod (0.05 wt

  10. Aqueous chemical growth and application of ZnO nanorods

    Postels, Bianca; Kasprzak, Anna; Mofor, Augustine C.; Wehmann, Hergo-Heinrich; Bakin, Andrey; Waag, Andreas [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Str. 66, 38106 Braunschweig (Germany)

    2007-07-01

    A very promising fabrication process for ZnO nanostructures is the aqueous chemical growth (ACG), since it is a cost efficient and low temperature approach. Using this growth technique we generated wafer-scale ZnO nanorod arrays on Si, sapphire, ITO coated glass and even on flexible polymer substrates. ACG is found to be only weakly influenced by the substrate material and we are also able to control the dimensions of the ZnO nanorods. Another benefit of ACG is the ability to fabricate patterned arrays of ZnO nanorods by a selective growth process on structured metallised surfaces. Results of structural analysis with SEM and XRD are reported. Additionally, optical properties were investigated by PL measurements. First attempts on the preparation of dye sensitised solar cells (DSSCs) are also reported. Here, the traditional sintered TiO{sub 2} nanoparticles are replaced by a densely packed and vertically aligned array of ACG ZnO nanorods. The size and morphology of the ZnO nanorods can be controlled. The influence of the length of the nanorods on the cell properties is investigated. A vapour phase transport technique was also used as alternative growth method.

  11. Oxidative desulfurization of diesel by potato based-carbon as green support for H5PMo10V2O40: Efficient composite nanorod catalyst

    Ezzat Rafiee

    2017-07-01

    Full Text Available The C@POM (carbon@polyoxometalate containing H3PMo12O40 (PMo12, H5PMo10V2O40 (PMo10V2, H6PMo9V3O40 (PMo9V3, H7PMo8V4O40 (PMo8V4, H3PW12O40 (PW, and H4SiW12O40 (SiW were prepared from natural potato as green, and cheap catalyst support source. The C@PMo10V2 was found to be a unique, effective, and eco-friendly catalyst for selective oxidation of sulfides, using 30% aq. H2O2. C@PMo10V2 composite was characterized by X-ray diffraction spectroscopy (XRD, energy dispersive X-ray spectroscopy (EDX, scanning electron microscopy (SEM, thermal gravimetric analysis (TGA, Fourier transform infrared (FT-IR spectrophotometry, zeta sizer, and zeta potential. The XRD results show that during immobilization PMo10V2 on the carbon catalyst support (CCS, the crystallite structure of PMo10V2 and CCS was not changed. The SEM results show that PMo10V2 crystals deposited on the surface CCS rods as composite nanorod structure. A variety of sulfides, sulfur-containing model and real oil were oxidized with the C@PMo10V2/H2O2 at room temperature. Recovered catalyst show excellent activity for at least four repeating cycles.

  12. ß-Ga2O3 nanorod synthesis with a one-step microwave irradiation hydrothermal method and its efficient photocatalytic degradation for perfluorooctanoic acid.

    Zhao, Baoxiu; Li, Xiang; Yang, Long; Wang, Fen; Li, Jincheng; Xia, Wenxiang; Li, Weijiang; Zhou, Li; Zhao, Colin

    2015-01-01

    ß-Ga2O3 nanorod was first directly prepared by the microwave irradiation hydrothermal way without any subsequent heat treatments, and its characterizations were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), UV-Vis diffuse reflection spectroscopy techniques, and also its photocatalytic degradation for perfluorooctanoic acid (PFOA) was investigated. XRD patterns revealed that ß-Ga2O3 crystallization increased with the enhancement of microwave power and the adding of active carbon (AC). PFOA, as an environmental and persistent pollutant, is hard decomposed by hydroxyl radicals (HO·); however, it is facilely destroyed by ß-Ga2O3 photocatalytic reaction in an anaerobic atmosphere. The important factors such as pH, ß-Ga2O3 dosage and bubbling atmosphere were researched, and the degradation and defluorination was 98.8% and 56.2%, respectively. Reductive atmosphere reveals that photoinduced electron may be the major reactant for PFOA. Furthermore, the degradation kinetics for PFOA was simulated and constant and half-life was calculated, respectively. © 2014 The American Society of Photobiology.

  13. Diameter Effect of Silver Nanorod Arrays to Surface-enhanced Raman Scattering

    Gu, Geun Hoi; Kim, Min Young; Yoon, Hyeok Jin; Suh, Jung Sang

    2014-01-01

    The effect the diameter of silver nanorod arrays whose distance between the nanorods was uniform at 65 nm have on Surface-enhanced Raman Scattering (SERS) has been studied by varying the diameter from 28 to 51 nm. Nanorod length was fixed at approximately 62 nm, which is the optimum length for SERS by excitation with a 632.8 nm laser line. The transverse and longitudinal modes of the surface plasmon of these silver nanorods were near 400 and 630 nm, respectively. The extinction of the longitudinal mode increased with increasing nanorod diameter, while the transverse mode did not change significantly. High-quality SERS spectra of p-aminothiophenol and benzenethiol adsorbed on the tips of the silver nanorods were observed by excitation with a 632.8 nm laser line. The SERS enhancement increased with increasing nanorod diameter. We concluded that the SERS enhancement increases when the diameter of silver nanorods is increased mainly by increasing the excitation efficiency of the longitudinal mode. The enhancement factor for the silver nanorods with a 51 nm diameter was approximately 2 Χ 10 7

  14. Mechanism analysis and evaluation methodology of regenerative braking contribution to energy efficiency improvement of electrified vehicles

    Lv, Chen; Zhang, Junzhi; Li, Yutong; Yuan, Ye

    2015-01-01

    Highlights: • The energy flow of an electric vehicle with regenerative brake is analyzed. • Methodology for measuring the regen brake contribution is discussed. • Evaluation parameters of regen brake contribution are proposed. • Vehicle tests are carried out on chassis dynamometer. • Test results verify the evaluation method and parameters proposed. - Abstract: This article discusses the mechanism and evaluation methods of contribution brought by regenerative braking to electric vehicle’s energy efficiency improvement. The energy flow of an electric vehicle considering the braking energy regeneration was analyzed. Then, methodologies for measuring the contribution made by regenerative brake to vehicle energy efficiency improvement were introduced. Based on the energy flow analyzed, two different evaluation parameters were proposed. Vehicle tests were carried out on chassis dynamometer under typical driving cycles with three different control strategies. The experimental results the difference between the proposed two evaluation parameters, and demonstrated the feasibility and effectiveness of the evaluation methodologies proposed

  15. Numerical investigation of radiative properties and surface plasmon resonance of silver nanorod dimers on a substrate

    An, Wei; Zhu, Tong; Zhu, QunZhi

    2014-01-01

    When the distance between two silver nanoparticles is small enough, interparticle surface plasmon coupling has a great impact on their radiative properties. It is becoming a promising technique to use in the sensing and imaging. A model based on finite difference time domain method is developed to investigate the effect of the assembled parameters on the radiative properties and the field-enhancement effect of silver nanorod dimer. The numerical results indicate that the radiative properties of silver nanorod dimer are very sensitive to the assembled angle and the polarization orientation of incident wave. There is great difference on the intensity and location of field-enhancement effect for the cases of different assembled angle and polarization. The most intensive field-enhancement effect occurs in the middle of two nanorods when two nanorods is assembled head to head and the polarization orientation parallels to the length axis of nanorods. Moreover, compared with the single nanorod, the wavelength of extinction peak of dimer has a red-shift, and the intensity of field-enhancement effect on the dimer is more intensive than that of single particle. With the increasing of particle length, extinction cross-section of silver nanorod dimer rises, while extinction efficiency and scattering efficiency firstly increase then drop down gradually. In addition, the extinction peaks of silver nanorod dimer on the substrate are smaller than that without the substrate, and their extinction peaks has a red-shift compared with that without the substrate. -- Highlights: ► Radiative properties of silver nanorod dimer are very sensitive to the assembled angle. ► The projective length of nanorod dimer on the polarization orientation is crucial. ► Compared with single nanorod, wavelength of extinction peak of dimer has a red-shift. ► Extinction peaks of dimer on the substrate are smaller than that without the substrate

  16. CONTRIBUTIONS OF MICROFINANCE INSTITUTIONS TO ECONOMIC EFFICIENCY OF CASSAVA FARMERS IN ABIA STATE, NIGERIA

    Kingsley Chukwuemeka OBIKE

    2014-10-01

    Full Text Available The study examined contributions of microfinance institutions to economic efficiency of cassava farmers in Abia state, Nigeria. A multistage random sampling technique was adopted in collecting cross sectional data on a sample size of 240 respondents (120 MFI beneficiaries and 120 non beneficiaries. Primary Data was collected by administering questionnaire on cassava farmers. The result showed that economic efficiency of MFI beneficiaries was influenced by wage rate, price of fertilizer and adjusted Y (output, while wage rate, price of fertilizer and price of cassava cutting s are variables that influenced economic efficiency of non beneficiaries. The t – test analysis confirmed that MFI beneficiaries had higher economic efficiency advantage compared with non beneficiaries. It is recommended that government agricultural policy should take positive steps to reduce interest rate to encourage MFI efforts in providing the necessary platform to encourage higher efficiency in cassava production in Abia state, Nigeria.

  17. New evaluation methodology of regenerative braking contribution to energy efficiency improvement of electric vehicles

    Qiu, Chengqun; Wang, Guolin

    2016-01-01

    Highlights: • Two different contribution ratio evaluation parameters according to the deceleration braking process are proposed. • Methodologies for calculating the contribution made by regenerative brake to improve vehicle energy efficiency are proposed. • Road test results imply that the proposed parameters are effective. - Abstract: Comprehensive research is conducted on the design and control of a regenerative braking system for electric vehicles. The mechanism and evaluation methods of contribution brought by regenerative braking to improve electric vehicle’s energy efficiency are discussed and analyzed by the energy flow. Methodologies for calculating the contribution made by regenerative brake are proposed. Additionally a new regenerative braking control strategy called “serial 2 control strategy” is introduced. Moreover, two control strategies called “parallel control strategy” and “serial 1 control strategy” are proposed as the comparative control strategy. Furthermore, two different contribution ratio evaluation parameters according to the deceleration braking process are proposed. Finally, road tests are carried out under China typical city regenerative driving cycle standard with three different control strategies. The serial 2 control strategy offers considerably higher regeneration efficiency than the parallel strategy and serial 1 strategy.

  18. [Efficiency indicators to contribute to sustainability of health services in Spain].

    García, E I; Mira Solves, J J; Guilabert Mora, M

    2014-01-01

    Identifying a minimum set of efficiency indicators calculated from current information sources. Interventions adopted from the analysis of these indicators could contribute to health services sustainability. We applied the discussion group technique. A total of 23 quality coordinators from around the country and the representatives of the regional quality societies in SECA (Spanish Society for Quality in Healthcare) participated. Ten efficiency indicators useful for integrated management areas were identified and accepted, 5 in the area of primary care and 5 for hospital management. The efficiency indicators agreed upon could contribute to the sustainability of the health system without this affecting the quality of care. Copyright © 2014 SECA. Published by Elsevier Espana. All rights reserved.

  19. Microstructures, surface properties, and topotactic transitions of manganite nanorods.

    Gao, Tao; Krumeich, Frank; Nesper, Reinhard; Fjellvåg, Helmer; Norby, Poul

    2009-07-06

    Manganite (gamma-MnOOH) nanorods with typical diameters of 20-500 nm and lengths of several micrometers were prepared by reacting KMnO(4) and ethanol under hydrothermal conditions. Synchrotron X-ray diffraction (XRD) reveal that the gamma-MnOOH nanorods crystallize in the monoclinic space group P2(1)/c with unit cell dimensions a = 5.2983(3) A, b = 5.2782(2) A, c = 5.3067(3) A, and beta = 114.401(2) degrees . Transmission electron microscopy shows that the gamma-MnOOH nanorods are single crystalline and that lateral attachment occurs for primary rods elongated along 101. X-ray photoelectron spectroscopy studies indicate that the surfaces of the gamma-MnOOH nanorods are hydrogen deficient and compensated by surface complexation. The Raman scattering spectrum features five main contributions at 360, 389, 530, 558, and 623 cm(-1) along with four weak ones at 266, 453, 492, and 734 cm(-1), attributed to Mn-O vibrations within MnO(6) octahedral frameworks. The structural stability of the gamma-MnOOH nanorods was discussed by means of in situ time-resolved synchrotron XRD. The monoclinic gamma-MnOOH nanorods transform into tetragonal beta-MnO(2) upon heating in air at about 200 degrees C. The reaction is topotactic and shows distinctive differences from those seen for bulk counterparts. A metastable, intermediate phase is observed, possibly connected with hydrogen release via the interstitial (1 x 1) tunnels of the gamma-MnOOH nanorods.

  20. Mean-variance portfolio selection and efficient frontier for defined contribution pension schemes

    Højgaard, Bjarne; Vigna, Elena

    We solve a mean-variance portfolio selection problem in the accumulation phase of a defined contribution pension scheme. The efficient frontier, which is found for the 2 asset case as well as the n + 1 asset case, gives the member the possibility to decide his own risk/reward profile. The mean...... as a mean-variance optimization problem. It is shown that the corresponding mean and variance of the final fund belong to the efficient frontier and also the opposite, that each point on the efficient frontier corresponds to a target-based optimization problem. Furthermore, numerical results indicate...... that the largely adopted lifestyle strategy seems to be very far from being efficient in the mean-variance setting....

  1. Magnetic-plasmonic multilayered nanorods

    Thumthan, Orathai

    Multilayered nanorods which consist of alternating magnetic layers separated by Au layers combine two distinctive properties, magnetic properties and surface plasmonic resonance (SPR) properties into one nano-entity. Their magnetic properties are tunable by changing the layer thickness, varying from single domain to superparamagnetic state. Superparamagnetic is a key requirement for magnetic nanoparticles for bioapplications. Superparamagnetic nanoparticles exhibit high magnetic moments at low applied magnetic field while retain no magnetic moments when magnetic field is removed preventing them from aggregation due to magnetic attraction. Au layers in the nanorods provide anchorage sites for functional group attachment. Also, Au nanodisks exhibit SPR properties. The SPR peak can be tuned from 540 nm to 820 nm by controlling the thickness of magnetic segments while keeping Au thickness constant. In this research, there are three types of multilayered nanorod have been fabricated: Au/NiFe nanorods, Au/Fe nanorods, and Au/Co nanorods. These magnetic nanorods were fabricated by templated electrodeposition into the channels in Anodic Aluminum Oxide (AAO) membrane. The setup for AAO fabrication was developed as a part of this research. Our fabricated AAO membrane has channels with a diameter ranging from 40nm to 80 nm and a thickness of 10um to 12um. Magnetic properties of nanorods such as saturation field, saturation moment, coercivity and remanence are able to manipulate through their shape anisotropy. The magnetization will be easier in long axis rather than short axis of particle. In addition, Au nanodisks in the nanorod structure are not only serving as anchorage sites for functional groups but also provide SPR properties. Under irradiation of light Au nanodisks strongly absorb light at SPR frequency which ranging from 540 nm to 820 nm by controlling the thickness of magnetic segments while keeping Au thickness constant. The SPR tunability of nanorods in near

  2. X-ray characterisation of single GaAs nanorods grown on Si

    Biermanns, Andreas; Davydok, A.; Pietsch, Ullrich [Universitaet Siegen (Germany). Festkoerperphysik; Breuer, Steffen; Geelhaar, Lutz [Paul-Drude-Institut fuer Festkoerperelektronik, Berlin (Germany)

    2010-07-01

    Semiconductor nanorods are of particular interest for new semiconductor devices. The nanorod approach can be used to form radial or axial heterostructures of materials with a large lattice mismatch. For the inspection of average structural parameters of the nanorods, typically X-ray or electron diffraction techniques are used. Alternatively, transmission electron microscopy can be used to inspect few individual nanorods after respective sample preparation. Complementary, recent developments in X-ray optics allow to focus a synchrotron beam down to the nanometer scale and to perform nondestructive diffraction studies at several individual nano-objects grown the same substrate. In this contribution we report on X-ray diffraction studies at individual GaAs nanorods grown Au seed-free on a Si[111] substrate. Due to the nanometer-sized x-ray beam, size and lattice parameters of individual nanorods could be measured and compared to the value obtained from the whole ensemble. Using the coherence properties of the focused beam we could observe speckle-like interference fringes in the surrounding of particular sensitive Bragg reflections which are a measure for the appearance of stacking faults within the nanorods. The separation of the speckles could be used to estimate the number of stacking faults and the size of the coherently scattering nanorod-segments.

  3. WO3 nanorods-modified carbon electrode for sustained electron uptake from Shewanella oneidensis MR-1 with suppressed biofilm formation

    Zhang, Feng; Yuan, Shi-Jie; Li, Wen-Wei; Chen, Jie-Jie; Ko, Chi-Chiu; Yu, Han-Qing

    2015-01-01

    Highlights: • WO 3 nanorods-modified carbon paper was used as the anode of MFC. • WO 3 nanorods suppressed biofilm growth on the electrode surface. • Sustained electron transfer from cells to electrode via riboflavin was achieved. • C–WO 3 nanorods enable stable and efficient EET process in long-time operation. - Abstract: Carbon materials are widely used as electrodes for bioelectrochemical systems (BES). However, a thick biofilm tends to grow on the electrode surface during continuous operation, resulting in constrained transport of electrons and nutrients at the cell-electrode interface. In this work, we tackled this problem by adopting a WO 3 -nanorods modified carbon electrode (C–WO 3 nanorods), which completely suppressed the biofilm growth of Shewanella Oneidensis MR-1. Moreover, the C–WO 3 nanorods exhibited high electric conductivity and strong response to riboflavin. These two factors together make it possible for the C–WO 3 nanorods to maintain a sustained, efficient process of electron transfer from the MR-1 planktonic cells. As a consequence, the microbial fuel cells with C–WO 3 nanorods anode showed more stable performance than the pure carbon paper and WO 3 -nanoparticles systems in prolonged operation. This work suggests that WO 3 nanorods have the potential to be used as a robust and biofouling-resistant electrode material for practical bioelectrochemical applications

  4. After-installation service, a contribution to enhanced economic efficiency of reactors

    Bilger, H.

    1996-01-01

    After-installation service agreements are concluded in general for the following plant systems or tasks: power operation, inspection and repair during outages, plant enhancements (retrofitting), instrumentation and control (software). The paper gives various examples selected from power plant practice in Germany, showing that service contracts are a major factor contributing to maintaining economic efficiency, or enhancing it. Examples of nuclear power plant management abroad relying on service contracts are also given (USA, France, Japan). (orig./HP) [de

  5. Far-Infrared Absorption of PbSe Nanorods

    Hyun, Byung-Ryool

    2011-07-13

    Measurements of the far-infrared absorption spectra of PbSe nanocrystals and nanorods are presented. As the aspect ratio of the nanorods increases, the Fröhlich sphere resonance splits into two peaks. We analyze this splitting with a classical electrostatic model, which is based on the dielectric function of bulk PbSe but without any free-carrier contribution. Good agreement between the measured and calculated spectra indicates that resonances in the local field factors underlie the measured spectra. © 2011 American Chemical Society.

  6. Can market oriented economic reforms contribute to energy efficiency improvement? Evidence from China

    Fan Ying; Liao Hua; Wei Yiming

    2007-01-01

    Since China accelerated its market oriented economic reforms at the end of 1992, its energy intensity has declined 3.6% annually over 1993-2005. However, its energy intensity declined 4.2% annually during its first reform period 1979-1992. Therefore, can we conclude that the accelerated marketization since the end of 1992 has made no contribution to its energy efficiency improvement? In order to answer this challenging question, we examine the changes of energy own-price elasticity, as well as the elasticities of substitution between energy and non-energy (capital and labor) in China during the periods of 1979-1992 and 1993-2003. Generally, in transition or developing economies, holding the technology and output level fixed, if the energy own-price elasticity (algebraic value) declines or the substitution elasticity between factors rises, they will contribute to energy efficiency improvement. Our empirical study finds that: (1) during 1979-1992, the energy own-price elasticity is positive (0.285), and capital-energy, labor-energy are both Morishima complementary; which indicates a distorted energy price and inefficient allocation; and (2) during 1993-2003, the own-price elasticity for energy is negative (-1.236), and capital-energy and labor-energy are both Morishima substitute. All factor demands become more elastic, and all elasticities of substitution increase. The implication is that the accelerated marketization contributes substantially to energy efficiency improvement since 1993

  7. The contribution of energy efficiency to sustainable development in developing countries

    Levine, M.D.; Meyers, S.

    1992-01-01

    The demand for energy services is growing rapidly in developing countries. Low levels of energy efficiency in electric power supply and in energy use mean that the energy sector threatens to absorb an intolerably high share of available financial resources. Energy inefficiency also contributes to local and global environmental problems. A strategy of vigorously improving energy efficiency is thus a key element of a sustainable development path. Results reported in this paper show that there is considerable room for efficiency improvement in both existing and new capital stocks, but a much larger effort than presently underway is essential if the potential is to be realized. Assistance from the industrialized countries can play a major role in such an effort. (author). 18 refs, 5 figs, 1 tab

  8. Unusual attempt to direct the growth of bimetallic Ag@Pt nanorods on electrochemically reduced graphene oxide nanosheets by electroless exchange of Cu by Pt for an efficient alcohol oxidation

    Jeena, S. E.; Gnanaprakasam, P.; Selvaraju, T.

    2017-01-01

    A simple and an efficient tool for the direct growth of bimetallic Ag@Pt nanorods (NRDs) on electrochemically reduced graphene oxide (ERGO) nanosheets was developed at glassy carbon electrode (GCE). Initially, Cu shell was grown on Ag core as Ag@Cu NRD by the seed-mediated growth method. Accordingly, Cu shell has been successfully replaced by Pt using the electroless galvanic replacement method with ease by effective functionalization of L-tryptophan on ERGO surface (L-ERGO), which eventually plays an important role in the direct growth of one-dimensional bimetallic NRDs. As a result, the synthesized Ag@Pt NRD-supported L-ERGO nanosheets (Ag@Pt NRDs/L-ERGO/GCE) were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDAX) and Raman spectroscopy. Anodic stripping voltammetry was used to explore its electrochemical properties. Finally, the developed bimetallic Ag@Pt NRDs/L-ERGO/GCEs were studied as a better electrocatalyst compared to the commercial catalysts such as Pt40/C or Pt20/C-loaded electrode for the oxidation of ethanol or methanol with a high tolerance level and an enhanced current density. In addition, the long-term stability was studied using chronoamperometry for 1000 s at the bimetallic NRD electrode for alcohol oxidation which impedes the fouling properties. The unfavourable and favourable electrooxidation of ethanol at Ag@Cu NRDs/L-ERGO/GCE (a) and Ag@Pt NRDs/L-ERGO/GCE (b) is discussed. The synergistic effect of Ag core and catalytic properties of Pt shell at Ag@Pt NRDs/L-ERGO/GCE tend to strongly minimize the CO poisoning effect and enhanced ethanol electrooxidation.

  9. Unusual attempt to direct the growth of bimetallic Ag@Pt nanorods on electrochemically reduced graphene oxide nanosheets by electroless exchange of Cu by Pt for an efficient alcohol oxidation

    Jeena, S. E.; Gnanaprakasam, P.; Selvaraju, T.

    2017-01-01

    A simple and an efficient tool for the direct growth of bimetallic Ag@Pt nanorods (NRDs) on electrochemically reduced graphene oxide (ERGO) nanosheets was developed at glassy carbon electrode (GCE). Initially, Cu shell was grown on Ag core as Ag@Cu NRD by the seed-mediated growth method. Accordingly, Cu shell has been successfully replaced by Pt using the electroless galvanic replacement method with ease by effective functionalization of L-tryptophan on ERGO surface (L-ERGO), which eventually plays an important role in the direct growth of one-dimensional bimetallic NRDs. As a result, the synthesized Ag@Pt NRD-supported L-ERGO nanosheets (Ag@Pt NRDs/L-ERGO/GCE) were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDAX) and Raman spectroscopy. Anodic stripping voltammetry was used to explore its electrochemical properties. Finally, the developed bimetallic Ag@Pt NRDs/L-ERGO/GCEs were studied as a better electrocatalyst compared to the commercial catalysts such as Pt_4_0/C or Pt_2_0/C-loaded electrode for the oxidation of ethanol or methanol with a high tolerance level and an enhanced current density. In addition, the long-term stability was studied using chronoamperometry for 1000 s at the bimetallic NRD electrode for alcohol oxidation which impedes the fouling properties. The unfavourable and favourable electrooxidation of ethanol at Ag@Cu NRDs/L-ERGO/GCE (a) and Ag@Pt NRDs/L-ERGO/GCE (b) is discussed. The synergistic effect of Ag core and catalytic properties of Pt shell at Ag@Pt NRDs/L-ERGO/GCE tend to strongly minimize the CO poisoning effect and enhanced ethanol electrooxidation.

  10. Unusual attempt to direct the growth of bimetallic Ag@Pt nanorods on electrochemically reduced graphene oxide nanosheets by electroless exchange of Cu by Pt for an efficient alcohol oxidation

    Jeena, S. E.; Gnanaprakasam, P. [Karunya University, Department of Chemistry (India); Selvaraju, T., E-mail: veluselvaraju@gmail.com [Bharathiar University, Department of Chemistry (India)

    2017-01-15

    A simple and an efficient tool for the direct growth of bimetallic Ag@Pt nanorods (NRDs) on electrochemically reduced graphene oxide (ERGO) nanosheets was developed at glassy carbon electrode (GCE). Initially, Cu shell was grown on Ag core as Ag@Cu NRD by the seed-mediated growth method. Accordingly, Cu shell has been successfully replaced by Pt using the electroless galvanic replacement method with ease by effective functionalization of L-tryptophan on ERGO surface (L-ERGO), which eventually plays an important role in the direct growth of one-dimensional bimetallic NRDs. As a result, the synthesized Ag@Pt NRD-supported L-ERGO nanosheets (Ag@Pt NRDs/L-ERGO/GCE) were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDAX) and Raman spectroscopy. Anodic stripping voltammetry was used to explore its electrochemical properties. Finally, the developed bimetallic Ag@Pt NRDs/L-ERGO/GCEs were studied as a better electrocatalyst compared to the commercial catalysts such as Pt{sub 40}/C or Pt{sub 20}/C-loaded electrode for the oxidation of ethanol or methanol with a high tolerance level and an enhanced current density. In addition, the long-term stability was studied using chronoamperometry for 1000 s at the bimetallic NRD electrode for alcohol oxidation which impedes the fouling properties. The unfavourable and favourable electrooxidation of ethanol at Ag@Cu NRDs/L-ERGO/GCE (a) and Ag@Pt NRDs/L-ERGO/GCE (b) is discussed. The synergistic effect of Ag core and catalytic properties of Pt shell at Ag@Pt NRDs/L-ERGO/GCE tend to strongly minimize the CO poisoning effect and enhanced ethanol electrooxidation.

  11. Plasmonic-cavity model for radiating nano-rod antennas

    Peng, Liang; Mortensen, N. Asger

    2014-01-01

    In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition and the ......In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition...... and the radiation efficiency. With our theoretical model, we show that besides the plasmonic resonances, efficient radiation takes advantage of (a) rendering a large value of the rods' radius and (b) a central-fed profile, through which the radiation efficiency can reach up to 70% and even higher in a wide...... frequency band. Our theoretical expressions and conclusions are general and pave the way for engineering and further optimization of optical antenna systems and their radiation patterns....

  12. An organic group contribution approach to radiative efficiency estimation of organic working fluid

    Zhang, Xinxin; Kobayashi, Noriyuki; He, Maogang; Wang, Jingfu

    2016-01-01

    Highlights: • We use group contribution method to estimate radiative efficiency. • CFC, HCFC, HFC, HFE, and PFC were estimated using this method. • In most cases, the estimation value has a good precision. • The method is reliable for the estimation of molecule with a symmetric structure. • This estimation method can offer good reference for working fluid development. - Abstract: The ratification of the Montreal Protocol in 1987 and the Kyoto Protocol in 1997 mark an environment protection era of the development of organic working fluid. Ozone depletion potential (ODP) and global warming potential (GWP) are two most important indices for the quantitative comparison of organic working fluid. Nowadays, more and more attention has been paid to GWP. The calculation of GWP is an extremely complicated process which involves interactions between surface and atmosphere such as atmospheric radiative transfer and atmospheric chemical reactions. GWP of a substance is related to its atmospheric abundance and is a variable in itself. However, radiative efficiency is an intermediate parameter for GWP calculation and it is a constant value used to describe inherent property of a substance. In this paper, the group contribution method was adopted to estimate the radiative efficiency of the organic substance which contains more than one carbon atom. In most cases, the estimation value and the standard value are in a good agreement. The biggest estimation error occurs in the estimation of the radiative efficiency of fluorinated ethers due to its plenty of structure groups and its complicated structure compared with hydrocarbon. This estimation method can be used to predict the radiative efficiency of newly developed organic working fluids.

  13. Constructing MnO{sub 2}/single crystalline ZnO nanorod hybrids with enhanced photocatalytic and antibacterial activity

    Yu, Weiwei [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Liu, Tiangui, E-mail: tianguiliu@gmail.com [College of Physics and Microelectronics Science, Hunan University, Changsha 410082 (China); Cao, Shiyi; Wang, Chen [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Chen, Chuansheng, E-mail: 1666423158@qq.com [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China)

    2016-07-15

    In order to improve the photocatalytic and antibacterial activity of ZnO nanorods, ZnO nanorods decorated with MnO{sub 2} nanoparticles (MnO{sub 2}/ZnO nanorod hybrids) were prepared by using microwave assisted coprecipitation method under the influence of hydrogen peroxide, and the structure, photocatalytic activity and antibacterial property of the products were studied. Experimental results indicated that MnO{sub 2} nanoparticles are decorated on the surface of single crystalline ZnO nanorods. Moreover, the resultant MnO{sub 2}/ZnO nanorod hybrids have been proven to possess good photocatalytic and antibacterial activity, which their degradated efficiency for Rhodamin B (RhB) is twice as the pure ZnO nanorods. Enhancement for photocatalytic and antibacterial activity is mainly attributed to the low band gap energy and excellent electrochemical properties of MnO{sub 2} nanoparticles. - Graphical abstract: The MnO{sub 2}/single crystalline ZnO nanorods hybrids, which MnO{sub 2} nanoparticles are loaded on the surface of ZnO nanorods, were prepared by the step-by-step precipitation method under the assistance of ammonia and hydrogen peroxide. Display Omitted - Highlights: • MnO{sub 2}/ZnO nanorod hybrids were prepared by the step-by-step assembly method. • Single crystalline ZnO nanorods can be decorated by MnO{sub 2} nanoparticles. • MnO{sub 2}/ZnO nanorod hybrids possess good photocatalytic and antibacterial activity. • MnO{sub 2} can improve the photocatalytic activity of ZnO nanorods under visible light.

  14. Photovoltaic properties of ZnO nanorods/p-type Si heterojunction structures

    Rafal Pietruszka

    2014-02-01

    Full Text Available Selected properties of photovoltaic (PV structures based on n-type zinc oxide nanorods grown by a low temperature hydrothermal method on p-type silicon substrates (100 are investigated. PV structures were covered with thin films of Al doped ZnO grown by atomic layer deposition acting as transparent electrodes. The investigated PV structures differ in terms of the shapes and densities of their nanorods. The best response is observed for the structure containing closely-spaced nanorods, which show light conversion efficiency of 3.6%.

  15. Mean-variance portfolio selection and efficient frontier for defined contribution pension schemes

    Hoejgaard, B.; Vigna, E.

    2007-01-01

    We solve a mean-variance portfolio selection problem in the accumulation phase of a defined contribution pension scheme. The efficient frontier, which is found for the 2 asset case as well as the n + 1 asset case, gives the member the possibility to decide his own risk/reward profile. The mean-variance approach is then compared to other investment strategies adopted in DC pension schemes, namely the target-based approach and the lifestyle strategy. The comparison is done both in a theoretical...

  16. Calculation of contribution of multiple interactions and efficiency of neutron detectors

    Androsenko, A.A.; Androsenko, P.A.; Kazakov, L.E.; Kononov, V.N.; Poletaev, E.D.

    1986-01-01

    Results of calculation of multiple neutron interactions contribution to efficiency of detectors with 6 Li glass and 10 B plate in the energy range of 0.01-1 MeV are given. The calculation was performed by the Monte-Carlo method using BRAND program complex. It is shown that a correction value for multiple neutron interaction in 6 Li glass of 1 mm thickness constitutes 4.5 % at energy of up to 100 keV and at higher energies has a complex energy dependence reaching 25 % at 440 keV

  17. Optical imaging and magnetophoresis of nanorods

    Lim, Jit Kang; Tan, David X.; Lanni, Frederick; Tilton, Robert D.; Majetich, Sara A.

    2009-01-01

    Peclet number analysis is performed to probe the convective motion of nanospheres and nanorods under the influence of magnetophoresis and diffusion. Under most circumstances, magnetophoretic behaviour dominates diffusion for nanorods, as the magnetic field lines tend to align the magnetic moment along the rod axis. The synthesis and dispersion of fluorophore-tagged nanorods are described. Fluorescence microscopy is employed to image the nanorod motion in a magnetic field gradient. The preliminary experimental data are consistent with the Peclet number analysis.

  18. THE CONTRIBUTION OF ENERGY EFFICIENCY TOWARDS THE SUCCESS OF INDUSTRIAL ORGANISATIONS IN SOUTH AFRICA

    P.A. Gouws

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Internationally, governments and lobby groups increasingly put pressure on organisations to reduce their impact on the environment. To this end, various studies show the drivers, barriers, and contributions of energy efficiency towards a more sustainable environment, particularly through reduced greenhouse gas emissions and other by-products. In the study summarised in this paper, the factors that drive organisational success were compared with the effects that energy efficiency projects have on organisations. Methods, policies, and strategies on the application of energy efficiency were also studied. The findings are that, in general, most organisations have energy efficiency policies and strategies in place, and they include internal and external stakeholders in their energy efficiency efforts. These efforts also show a positive correlation with the factors that contribute to the perceived success of organisations in the South African industrial sector. These strategies must be maintained in the longer term, as energy efficiency will play a more important role in the future.

    AFRIKAANSE OPSOMMING: Organisasies, wêreldwyd, word toenemend onder druk geplaas deur regerings- en aksiegroepe om hul impak op die omgewing te verminder. Na aanleiding hiervan toon verskeie studies die drywers, struikelblokke en bydraes van energie-doeltreffendheid na ʼn meer volhoubare omgewing, veral ten opsigte van groenhuisgas-emissies en ander neweprodukte. In hierdie studie is die faktore wat die sukses van organisasies dryf vergelyk met die effek van die toepassing van energiedoeltreffendheidsprojekte op organisasies. Metodes, beleid en strategieë in terme van die toepassing van energiedoeltreffendheid is ook bestudeer. Die bevindinge is dat die meeste organisasies, oor die algemeen, beleid en strategieë in plek het in terme van energiedoeltreffendheid; dié organisasies sluit interne en eksterne belanghebbendes in waar hulle strewe na

  19. Fabrication of TiO_2 nanorod assembly grafted rGO (rGO@TiO_2-NR) hybridized flake-like photocatalyst

    Lv, Kangle; Fang, Shun; Si, Lingling; Xia, Yang; Ho, Wingkei; Li, Mei

    2017-01-01

    Highlights: • TiO_2 nanorod assembly grafted with GO hybrid was successfully fabricated. • TiO_2 nanorods can reduce the aggregation of TiO_2 nanoparticles on graphene. • This unique structure facilitates the injection of electron from TiO_2 to graphene. - Abstract: To efficiently separate the photo-generated electron–hole pairs of TiO_2 hybrid, anatase TiO_2 nanorod assembly grafted reduced graphene oxides (rGO@TiO_2-NR) hybrid was successfully fabricated using potassium titanium oxalate (PTO) and graphene oxides (GO) as starting materials and diethylene glycol (DEG) as reductant. The effect of GO content on the structure and photocatalytic activity of rGO@TiO_2-NR composite was systematically studied. Results show that, in the absence of GO, only TiO_2 microsphere assembly is obtained from TiO_2 nanorods. The presence of GO results in the formation of a flake-like TiO_2-nanorod-assembled grafted rGO hybrid. The photocatalytic activity of rGO@TiO_2-NR composite increases first and then decreases with increase in the amount of GO from 0 wt.% to 10 wt.%. The hybridized S4 sample prepared with 4 wt.% GO possesses the highest photocatalytic activity with a constant rate of 0.039 min"−"1 in the photocataytic degradation of Brilliant X-3B dye (X3B); this sample was enhanced more than three times when compared with pure TiO_2 sample (0.012 min"−"1). The enhanced photocatalytic activity of the rGO@TiO_2-NR hybrid was attributed to the strong interaction between TiO_2 nanorods and rGO. The unique hierarchical structure of 1D nanorod assembly TiO_2–rGO flakes facilitates the injection and transfer of photo-generated electrons from TiO_2 to graphene, thus retarding the recombination of electron–hole pairs and enhancing the photocatalytic activity. The enlarged BET surface areas, not only increasing the number of active sites, but also facilitating the adsorption of the dye, and improved light-harvesting ability also contribute to the enhanced photoreactivity

  20. Fabrication of TiO{sub 2} nanorod assembly grafted rGO (rGO@TiO{sub 2}-NR) hybridized flake-like photocatalyst

    Lv, Kangle, E-mail: lvkangle@mail.scuec.edu.cn [Department of Science and Environmental Studies, The Hong Kong Institute of Education, Taipo, N.T., Hong Kong (China); Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China); Fang, Shun; Si, Lingling; Xia, Yang [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China); Ho, Wingkei, E-mail: keithho@ied.edu.hk [Department of Science and Environmental Studies, The Hong Kong Institute of Education, Taipo, N.T., Hong Kong (China); Li, Mei [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China)

    2017-01-01

    Highlights: • TiO{sub 2} nanorod assembly grafted with GO hybrid was successfully fabricated. • TiO{sub 2} nanorods can reduce the aggregation of TiO{sub 2} nanoparticles on graphene. • This unique structure facilitates the injection of electron from TiO{sub 2} to graphene. - Abstract: To efficiently separate the photo-generated electron–hole pairs of TiO{sub 2} hybrid, anatase TiO{sub 2} nanorod assembly grafted reduced graphene oxides (rGO@TiO{sub 2}-NR) hybrid was successfully fabricated using potassium titanium oxalate (PTO) and graphene oxides (GO) as starting materials and diethylene glycol (DEG) as reductant. The effect of GO content on the structure and photocatalytic activity of rGO@TiO{sub 2}-NR composite was systematically studied. Results show that, in the absence of GO, only TiO{sub 2} microsphere assembly is obtained from TiO{sub 2} nanorods. The presence of GO results in the formation of a flake-like TiO{sub 2}-nanorod-assembled grafted rGO hybrid. The photocatalytic activity of rGO@TiO{sub 2}-NR composite increases first and then decreases with increase in the amount of GO from 0 wt.% to 10 wt.%. The hybridized S4 sample prepared with 4 wt.% GO possesses the highest photocatalytic activity with a constant rate of 0.039 min{sup −1} in the photocataytic degradation of Brilliant X-3B dye (X3B); this sample was enhanced more than three times when compared with pure TiO{sub 2} sample (0.012 min{sup −1}). The enhanced photocatalytic activity of the rGO@TiO{sub 2}-NR hybrid was attributed to the strong interaction between TiO{sub 2} nanorods and rGO. The unique hierarchical structure of 1D nanorod assembly TiO{sub 2}–rGO flakes facilitates the injection and transfer of photo-generated electrons from TiO{sub 2} to graphene, thus retarding the recombination of electron–hole pairs and enhancing the photocatalytic activity. The enlarged BET surface areas, not only increasing the number of active sites, but also facilitating the adsorption of

  1. All-silicon nanorod-based Dammann gratings.

    Li, Zile; Zheng, Guoxing; He, Ping'An; Li, Song; Deng, Qiling; Zhao, Jiangnan; Ai, Yong

    2015-09-15

    Established diffractive optical elements (DOEs), such as Dammann gratings, whose phase profile is controlled by etching different depths into a transparent dielectric substrate, suffer from a contradiction between the complexity of fabrication procedures and the performance of such gratings. In this Letter, we combine the concept of geometric phase and phase modulation in depth, and prove by theoretical analysis and numerical simulation that nanorod arrays etched on a silicon substrate have a characteristic of strong polarization conversion between two circularly polarized states and can act as a highly efficient half-wave plate. More importantly, only by changing the orientation angles of each nanorod can the arrays control the phase of a circularly polarized light, cell by cell. With the above principle, we report the realization of nanorod-based Dammann gratings reaching diffraction efficiencies of 50%-52% in the C-band fiber telecommunications window (1530-1565 nm). In this design, uniform 4×4 spot arrays with an extending angle of 59°×59° can be obtained in the far field. Because of these advantages of the single-step fabrication procedure, accurate phase controlling, and strong polarization conversion, nanorod-based Dammann gratings could be utilized for various practical applications in a range of fields.

  2. Effects of the aspect ratio on the dye adsorption of ZnO nanorods grown by using a sonochemical method for dye-sensitized solar cells

    Choi, Seok Cheol; Yun, Won Suk; Sohn, Sang Ho; Oh, Sang Jin

    2012-01-01

    Well-aligned ZnO nanorods for the photoelectrode of dye-sensitized solar cells (DSSCs) were grown via a sonochemical method, and the effects of their aspect ratios on the dye adsorption in DSSCs were studied. The control of the aspect ratio of well-aligned ZnO nanorods was performed by tuning the mole concentration of zinc acetate dehydrate in the range of 0.04 ∼ 0.06M. The dye amounts adsorbed in the ZnO nanorods were estimated from the UV-Visible absorbance by using the Beer-Lambert law. The efficiency of DSSCs with ZnO nanorods was measured to investigate the effects of the aspect ratio of the ZnO nanorods on the dye adsorption properties. A change in the aspect ratio of the ZnO nanorods was founded to yield a change in their dye adsorption ability, resulting in a change in the efficiency of the DSSCs.

  3. Size-dependent production of radicals in catalyzed reduction of Eosin Y using gold nanorods

    Weng, Guojun; Qi, Ying; Li, Jianjun; Zhao, Junwu, E-mail: nanoptzhao@163.com [Xi’an Jiaotong University, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology (China)

    2015-09-15

    Gold nanostructures have been widely used as catalysts for chemical processes, energy conversion, and pollution control. The size of gold nanocatalysts is thus paramount for their catalytic activity. In this paper, gold nanorods with different sizes were prepared by means of the improved seeding growth approach by adding aromatic additive. The sizes and aspect ratios of the obtained gold nanorods were calculated according to the TEM characterization. Then, we studied the catalytic activities of gold nanorods using a model reaction based on the reduction of Eosin Y by NaBH{sub 4}. By monitoring the absorption intensities of the radicals induced by gold nanorods in real time, we observed the clear size-dependent activity in the conversion of EY{sup 2−} to EY{sup 3−}. The conversion efficiency indicated that the gold nanorods with the smallest size were catalytically the most active probably due to their high number of coordinatively unsaturated surface atoms. In addition, a compensation effect dominated by the surface area of nanorods was observed in this catalytic reduction, which could be primarily attributed to the configuration of Eosin Y absorbed onto the surfaces of gold nanorods.

  4. Size-dependent production of radicals in catalyzed reduction of Eosin Y using gold nanorods

    Weng, Guojun; Qi, Ying; Li, Jianjun; Zhao, Junwu

    2015-01-01

    Gold nanostructures have been widely used as catalysts for chemical processes, energy conversion, and pollution control. The size of gold nanocatalysts is thus paramount for their catalytic activity. In this paper, gold nanorods with different sizes were prepared by means of the improved seeding growth approach by adding aromatic additive. The sizes and aspect ratios of the obtained gold nanorods were calculated according to the TEM characterization. Then, we studied the catalytic activities of gold nanorods using a model reaction based on the reduction of Eosin Y by NaBH 4 . By monitoring the absorption intensities of the radicals induced by gold nanorods in real time, we observed the clear size-dependent activity in the conversion of EY 2− to EY 3− . The conversion efficiency indicated that the gold nanorods with the smallest size were catalytically the most active probably due to their high number of coordinatively unsaturated surface atoms. In addition, a compensation effect dominated by the surface area of nanorods was observed in this catalytic reduction, which could be primarily attributed to the configuration of Eosin Y absorbed onto the surfaces of gold nanorods

  5. MIL-68 (In) nano-rods for the removal of Congo red dye from aqueous solution.

    Jin, Li-Na; Qian, Xin-Ye; Wang, Jian-Guo; Aslan, Hüsnü; Dong, Mingdong

    2015-09-01

    MIL-68 (In) nano-rods were prepared by a facile solvothermal synthesis using NaOAc as modulator agent at 100°C for 30 min. The BET test showed that the specific surface area and pore volume of MIL-68 (In) nanorods were 1252 m(2) g(-1) and 0.80 cm(3) g(-1), respectively. The as-prepared MIL-68 (In) nanorods showed excellent adsorption capacity and rapid adsorption rate for removal of Congo red (CR) dye from water. The maximum adsorption capacity of MIL-68 (In) nanorods toward CR reached 1204 mg g(-1), much higher than MIL-68 (In) microrods and most of the previously reported adsorbents. The adsorption process of CR by MIL-68 (In) nano-rods was investigated and found to be obeying the Langmuir adsorption model in addition to pseudo-second-order rate equation. Moreover, the MIL-68 (In) nanorods showed an acceptable reusability after regeneration with ethanol. All information gives an indication that the as-prepared MIL-68 (In) nanorods show their potential as the adsorbent for highly efficient removal of CR in wastewater. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Size-dependent production of radicals in catalyzed reduction of Eosin Y using gold nanorods

    Weng, Guojun; Qi, Ying; Li, Jianjun; Zhao, Junwu

    2015-09-01

    Gold nanostructures have been widely used as catalysts for chemical processes, energy conversion, and pollution control. The size of gold nanocatalysts is thus paramount for their catalytic activity. In this paper, gold nanorods with different sizes were prepared by means of the improved seeding growth approach by adding aromatic additive. The sizes and aspect ratios of the obtained gold nanorods were calculated according to the TEM characterization. Then, we studied the catalytic activities of gold nanorods using a model reaction based on the reduction of Eosin Y by NaBH4. By monitoring the absorption intensities of the radicals induced by gold nanorods in real time, we observed the clear size-dependent activity in the conversion of EY2- to EY3-. The conversion efficiency indicated that the gold nanorods with the smallest size were catalytically the most active probably due to their high number of coordinatively unsaturated surface atoms. In addition, a compensation effect dominated by the surface area of nanorods was observed in this catalytic reduction, which could be primarily attributed to the configuration of Eosin Y absorbed onto the surfaces of gold nanorods.

  7. Template-free hydrothermal synthesis and high photocatalytic activity of ZnWO4 nanorods

    Gao, Bin; Fan, Huiqing; Zhang, Xiaojun; Song, Lixun

    2012-01-01

    Highlights: ► ZnWO 4 nanorods with uniform diameter are successfully prepared through a template-free hydrothermal method. ► The crystallinity of the products is influenced by the pH value of initial precursor suspension. ► Photocatalytic activity of the ZnWO 4 nanorods for degradation of methylene blue is evaluated. ► The ZnWO 4 nanorods exhibit good stability of photocatalytic activity. - Abstract: ZnWO 4 nanorods are successfully synthesized by a template-free hydrothermal method, and are characterized in detail by X-ray diffractometer (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED). The results show that the ZnWO 4 nanorods with wolframite structure are well-crystallized single crystallites. The crystallinity of the products is influenced by the pH value of initial precursor suspension. The width and length of the synthesized samples increase with hydrothermal reaction temperature. The photocatalytic efficiency of the ZnWO 4 nanorods for degradation of methylene blue (MB) in aqueous solution under UV light irradiation declines greatly with increasing crystallinity. The ZnWO 4 nanorods prepared at pH of 4 have the best activity in photo-degradation of MB. After six recycles, photocatalytic activity loss of the catalyst is not obvious.

  8. Role of nanorods insertion layer in ZnO-based electrochemical metallization memory cell

    Mangasa Simanjuntak, Firman; Singh, Pragya; Chandrasekaran, Sridhar; Juanda Lumbantoruan, Franky; Yang, Chih-Chieh; Huang, Chu-Jie; Lin, Chun-Chieh; Tseng, Tseung-Yuen

    2017-12-01

    An engineering nanorod array in a ZnO-based electrochemical metallization device for nonvolatile memory applications was investigated. A hydrothermally synthesized nanorod layer was inserted into a Cu/ZnO/ITO device structure. Another device was fabricated without nanorods for comparison, and this device demonstrated a diode-like behavior with no switching behavior at a low current compliance (CC). The switching became clear only when the CC was increased to 75 mA. The insertion of a nanorods layer induced switching characteristics at a low operation current and improve the endurance and retention performances. The morphology of the nanorods may control the switching characteristics. A forming-free electrochemical metallization memory device having long switching cycles (>104 cycles) with a sufficient memory window (103 times) for data storage application, good switching stability and sufficient retention was successfully fabricated by adjusting the morphology and defect concentration of the inserted nanorod layer. The nanorod layer not only contributed to inducing resistive switching characteristics but also acted as both a switching layer and a cation diffusion control layer.

  9. Uptake, translocation, and toxicity of gold nanorods in maize

    Moradi Shahmansouri, Nastaran

    Nanomaterials are widely used in many different products, such as electronics, cosmetics, industrial goods, biomedical uses, and other material applications. The heavy emission of nanomaterials into the environment has motived increasing concern regarding the effects on ecosystems, food chains, and, human health. Plants can tolerate a certain amount of natural nanomaterials, but large amounts of ENMs released from a variety of industries could be toxic to plants and possibly threaten the ecosystem. Employing phytoremediation as a contamination treatment method may show promise. However a pre-requisite to successful treatment is a better understanding of the behavior and effects of nanomaterials within plant systems. This study is designed to investigate the uptake, translocation, bioavailability, and toxicity of gold nanorods in maize plants. Maize is an important food and feed crop that can be used to understand the potential hazardous effects of nanoparticle uptake and distribution in the food chain. The findings could be an important contribution to the fields of phytoremediation, agri-nanotechnology, and nanoparticle toxicity on plants. In the first experiment, hydroponically grown maize seedlings were exposed to similar doses of commercial non-coated gold nanorods in three sizes, 10x34 nm, 20x75 nm, and 40x96 nm. The three nanorod species were suspended in solutions at concentrations of 350 mg/l, 5.8 mg/l, and 14 mg/l, respectively. Maize plants were exposed to all three solutions resulting in considerably lower transpiration and wet biomass than control plants. Likewise, dry biomass was reduced, but the effect is less pronounced than that of transpiration and wet biomass. The reduced transpiration and water content, which eventually proved fatal to exposed plants, were most likely a result of toxic effect of gold nanorod, which appeared to physically hinder the root system. TEM images proved that maize plants can uptake gold particles and accumulate them in

  10. Ethanol sensing properties and dominant sensing mechanism of NiO-decorated SnO2 nanorod sensors

    Sun, Gun-Joo; Lee, Jae Kyung; Lee, Wan In; Dwivedi, Ram Prakash; Lee, Chongmu; Ko, Taegyung

    2017-05-01

    NiO-decorated SnO2 nanorods were synthesized by the thermal evaporation of Sn powders followed by the solvothermal deposition of NiO. A multi-networked p- n heterostructured nanorod sensor was fabricated by dropping the p-NiO-decorated n-SnO2 nanorods onto the interdigited electrode pattern and then annealing. The multi-networked p- n heterostructured nanorod sensor exhibited enhanced response to ethanol compared with the pristine SnO2 nanorod and NiO nanoparticle sensors. The former also exhibited a shorter sensing time for ethanol. Both sensors exhibited selectivity for ethanol over other volatile organic compounds (VOCs) such as HCHO, methanol, benzene and toluene and the decorated sensor exhibited superior selectivity to the other two sensors. In addition, the dominant sensing mechanism is discussed in detail by comparing the sensing properties and current-voltage characteristics of a p-NiO/ n-SnO2 heterostructured nanorod sensor with those of a pristine SnO2 nanorod sensor and a pristine NiO nanoparticle sensor. Of the two competing electronic mechanisms: a potential barrier-controlled carrier transport mechanism at a NiO-SnO2 p- n junction and a surface-depletio n-controlled carrier transport mechanism, the former has some contribution to the enhanced gas sensing performance of the p- n heterostructured nanorod sensor, however, its contribution is not as significant as that of the latter. [Figure not available: see fulltext.

  11. Vertically aligned ZnO@CdS nanorod heterostructures for visible light photoinactivation of bacteria

    Zirak, M.; Akhavan, O.; Moradlou, O.; Nien, Y.T.; Moshfegh, A.Z.

    2014-01-01

    Highlights: • Synthesis of vertically aligned ZnO@CdS nanorod heterostructures. • Effective antibacterial application of the ZnO@CdS nanorods under visible light irradiation. • Determination of the optimum loading of CdS on the ZnO nanorods in the antibacterial application. -- Abstract: Vertically aligned ZnO@CdS nanorod heterostructure films with various loadings of CdS nanoparticle shell were synthesized and applied in photoinactivation of Escherichia coli bacteria under visible light irradiation. While neither the bare ZnO nanorods (with band-gap energy (E g ) of ∼3.28 eV) under visible light irradiation nor the nanorod heterostructures in dark exhibited any significant antibacterial activity, the ZnO@CdS nanorod heterostructures (with E g ∼2.5–2.6 eV) could successfully inactivate the bacteria under visible light irradiation. Furthermore, it was found that an optimum loading of the CdS shell (corresponding to the effective thickness less than ∼15 nm) is required to achieve a complete inactivation of the bacteria after 24 h visible light irradiation at room temperature. Using X-ray photoelectron spectroscopy, the lower photoinactivation efficiencies of the ZnO@CdS nanorod heterostructure at CdS thicknesses lower and higher than the optimum one were assigned to lower amounts of CdS nanoparticles and OH bonds (substantially existed on the hydrothermally synthesized ZnO nanorods) which are responsible for absorption of the visible light and production of hydroxyl radicals, respectively. Water contact angle measurements showed that the sample with more surface OH groups has a more hydrophilic surface and so more antibacterial activity

  12. Vertically aligned ZnO@CdS nanorod heterostructures for visible light photoinactivation of bacteria

    Zirak, M. [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Akhavan, O., E-mail: oakhavan@sharif.edu [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-89694, Tehran (Iran, Islamic Republic of); Moradlou, O. [Department of Chemistry, Faculty of Sciences, Alzahra University, P.O. Box 1993893973, Tehran (Iran, Islamic Republic of); Nien, Y.T. [Department of Materials Science and Engineering, National Formosa University, Huwei District, Taiwan (China); Moshfegh, A.Z. [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-89694, Tehran (Iran, Islamic Republic of)

    2014-03-25

    Highlights: • Synthesis of vertically aligned ZnO@CdS nanorod heterostructures. • Effective antibacterial application of the ZnO@CdS nanorods under visible light irradiation. • Determination of the optimum loading of CdS on the ZnO nanorods in the antibacterial application. -- Abstract: Vertically aligned ZnO@CdS nanorod heterostructure films with various loadings of CdS nanoparticle shell were synthesized and applied in photoinactivation of Escherichia coli bacteria under visible light irradiation. While neither the bare ZnO nanorods (with band-gap energy (E{sub g}) of ∼3.28 eV) under visible light irradiation nor the nanorod heterostructures in dark exhibited any significant antibacterial activity, the ZnO@CdS nanorod heterostructures (with E{sub g} ∼2.5–2.6 eV) could successfully inactivate the bacteria under visible light irradiation. Furthermore, it was found that an optimum loading of the CdS shell (corresponding to the effective thickness less than ∼15 nm) is required to achieve a complete inactivation of the bacteria after 24 h visible light irradiation at room temperature. Using X-ray photoelectron spectroscopy, the lower photoinactivation efficiencies of the ZnO@CdS nanorod heterostructure at CdS thicknesses lower and higher than the optimum one were assigned to lower amounts of CdS nanoparticles and OH bonds (substantially existed on the hydrothermally synthesized ZnO nanorods) which are responsible for absorption of the visible light and production of hydroxyl radicals, respectively. Water contact angle measurements showed that the sample with more surface OH groups has a more hydrophilic surface and so more antibacterial activity.

  13. The (2 × 2) tunnels structured manganese dioxide nanorods with α phase for lithium air batteries

    Ghouri, Zafar Khan; Zahoor, Awan; Barakat, Nasser A. M.; Alsoufi, Mohammad S.; Bawazeer, Tahani M.; Mohamed, Ahmed F.; Kim, Hak Yong

    2016-02-01

    The (2 × 2) tunnels structured manganese dioxide nanorods with α phase (α-MnO2) are synthesized via simplistic hydrothermal method at low temperature. The obtained tunnels structured α-MnO2 nanorods are characterized by, Transmission electron microscopy, Scanning electron microscopy, and X-ray diffraction techniques. The oxygen reduction reaction (ORR) activity was studied by cyclic voltammetry and rotating ring-disc electrode voltammetry techniques in alkaline media. Moreover; the highly electrocatalytic tunnels structured α-MnO2 nanorods were then also applied as cathode in rechargeable Li-O2 cells. The Li-O2 cells exhibited initial discharge capacity as high as ∼4000 mAh/g with the tunnels structured α-MnO2 nanorods which was double the original capacity of the cells without any catalyst. Also we obtained 100% round trip efficiency upon cycling with limited capacity for more than 50 cycles.

  14. Biocompatible PEGylated gold nanorods as colored contrast agents for targeted in vivo cancer applications

    Kopwitthaya, Atcha; Yong, Ken-Tye; Hu, Rui; Roy, Indrajit; Ding, Hong; Vathy, Lisa A.; Bergey, Earl J.; Prasad, Paras N.

    2010-08-01

    In this contribution, we report the use of a PEGylated gold nanorods formulation as a colored dye for tumor labeling in vivo. We have demonstrated that the nanorod-targeted tumor site can be easily differentiated from the background tissues by the 'naked eye' without the need of sophisticated imaging instruments. In addition to tumor labeling, we have also performed in vivo toxicity and biodistribution studies of PEGylated gold nanorods in vivo by using BALB/c mice as the model. In vivo toxicity studies indicated no mortality or adverse effects or weight changes in BALB/c mice treated with PEGylated gold nanorods. This finding will provide useful guidelines in the future development of diagnostic probes for cancer diagnosis, optically guided tumor surgery, and lymph node mapping applications.

  15. Biocompatible PEGylated gold nanorods as colored contrast agents for targeted in vivo cancer applications

    Kopwitthaya, Atcha; Hu Rui; Roy, Indrajit; Ding Hong; Vathy, Lisa A; Bergey, Earl J; Prasad, Paras N [Institute for Lasers, Photonics and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY 14260-4200 (United States); Yong, Ken-Tye, E-mail: ktyong@ntu.edu.sg, E-mail: pnprasad@buffalo.edu [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2010-08-06

    In this contribution, we report the use of a PEGylated gold nanorods formulation as a colored dye for tumor labeling in vivo. We have demonstrated that the nanorod-targeted tumor site can be easily differentiated from the background tissues by the 'naked eye' without the need of sophisticated imaging instruments. In addition to tumor labeling, we have also performed in vivo toxicity and biodistribution studies of PEGylated gold nanorods in vivo by using BALB/c mice as the model. In vivo toxicity studies indicated no mortality or adverse effects or weight changes in BALB/c mice treated with PEGylated gold nanorods. This finding will provide useful guidelines in the future development of diagnostic probes for cancer diagnosis, optically guided tumor surgery, and lymph node mapping applications.

  16. ZnO nanorods/AZO photoanode for perovskite solar cells fabricated in ambient air

    La Ferrara, Vera; De Maria, Antonella; Rametta, Gabriella; Della Noce, Marco; Vittoria Mercaldo, Lucia; Borriello, Carmela; Bruno, Annalisa; Delli Veneri, Paola

    2017-08-01

    ZnO nanorods are a good candidate for replacing standard photoanodes, such as TiO2, in perovskite solar cells and in principle superseding the high performances already obtained. This is possible because ZnO nanorods have a fast electron transport rate due to their large surface area. An array of ZnO nanorods is grown by chemical bath deposition starting from Al-doped ZnO (AZO) used both as a seed layer and as an efficient transparent anode in the visible spectral range. In particular, in this work we fabricate methylammonium lead iodide (CH3NH3PbI3) perovskite solar cells using glass/AZO/ZnO nanorods/perovskite/Spiro-OMeTAD/Au as the architecture. The growth of ZnO nanorods has been optimized by varying the precursor concentrations, growth time and solution temperature. All the fabrication process and photovoltaic characterizations have been carried out in ambient air and the devices have not been encapsulated. Power conversion efficiency as high as 7.0% has been obtained with a good stability over 20 d. This is the highest reported value to the best of our knowledge and it is a promising result for the development of perovskite solar cells based on ZnO nanorods and AZO.

  17. Growth and structure of carbide nanorods

    Lieber, C.M.; Wong, E.W.; Dai, H.; Maynor, B.W.; Burns, L.D.

    1996-01-01

    Recent research on the growth and structure of carbide nanorods is reviewed. Carbide nanorods have been prepared by reacting carbon nanotubes with volatile transition metal and main group oxides and halides. Using this approach it has been possible to obtain solid carbide nanorods of TiC, SiC, NbC, Fe 3 C, and BC x having diameters between 2 and 30 nm and lengths up to 20 microm. Structural studies of single crystal TiC nanorods obtained through reactions of TiO with carbon nanotubes show that the nanorods grow along both [110] and [111] directions, and that the rods can exhibit either smooth or saw-tooth morphologies. Crystalline SiC nanorods have been produced from reactions of carbon nanotubes with SiO and Si-iodine reactants. The preferred growth direction of these nanorods is [111], although at low reaction temperatures rods with [100] growth axes are also observed. The growth mechanisms leading to these novel nanomaterials have also been addressed. Temperature dependent growth studies of TiC nanorods produced using a Ti-iodine reactant have provided definitive proof for a template or topotactic growth mechanism, and furthermore, have yielded new TiC nanotube materials. Investigations of the growth of SiC nanorods show that in some cases a catalytic mechanism may also be operable. Future research directions and applications of these new carbide nanorod materials are discussed

  18. ZnO-nanorods: A possible white LED phosphor

    Sarangi, Sachindra Nath; T., Arun; Ray, Dinseh K.; Sahoo, Pratap Kumar; Nozaki, Shinji; Sugiyama, Noriyuki; Uchida, Kazuo

    2017-05-01

    The white light-emitting diodes (LEDs) have drawn much attention to replace conventional lighting sources because of low energy consumption, high light efficiency and long lifetime. Although the most common approach to produce white light is to combine a blue LED chip and a yellow phosphor, such a white LED cannot be used for a general lighting application, which requires a broad luminescence spectrum in the visible wavelength range. We have successfully chemically synthesized the ZnO nanorods showing intense broad luminescence in the visible wavelength range and made a white LED using the ZnO nanorods as phosphor excited with a blue LED. Their lengths and diameters were 2 - 10 μm and 200 - 800 nm, respectively. The wurtzite structure was confirmed by the x-ray diffraction measurement. The PL spectrum obtained by exciting the ZnO nanorods with the He-Cd laser has two peaks, one associated with the near band-edge recombination and the other with recombination via defects. The peak intensity of the near band-edge luminescence at 388 nm is much weaker than that of the defect-related luminescence. The latter luminescence peak ranges from 450 to 850 nm and broad enough to be used as a phosphor for a white LED. A white LED has been fabricated using a blue LED with 450 nm emission and ZnO nanorod powders. The LED performances show a white light emission and the electroluminescence measurement shows a stiff increase in white light intensity with increasing blue LED current. The Commission International de1'Eclairage (CIE) chromaticity colour coordinates of 450 nm LED pumped white emission shows a coordinate of (0.31, 0.32) for white LED at 350 mA. These results indicate that ZnO nanorods provides an alternate and effective approach to achieve high-performance white LEDs and also other optoelectronic devices.

  19. Physiological investigation of gold nanorods toward watermelon.

    Wan, Yujie; Li, Junli; Ren, Hongxuan; Huang, Jin; Yuan, Hong

    2014-08-01

    The objective of the present study was to evaluate the phytotoxicity and oxidant stress of the gold nanorods toward watermelon, and hence give a quantitative risk assessment of both seeds and plants phase. The seed germination, the activity of antioxidant enzymes, and the contents of soluble protein and malondialdehyde (MDA) have been measured while the plant roots were observed by transmission electron microscopy (TEM). It was found that the gold nanorods significantly promoted the root elongation. Furthermore, the results on the enzymes activities of plant indicated that oxidative stress happened in the plant treated with gold nanorods. However, the gold nanorods resulted in the phytotoxicity toward plant especially at high concentration. The TEM images of the plant roots with and without the treatment of gold nanorods showed the significant different size of starch granules. In conclusion, significant physiological changes of plant occurred after treatment with the gold nanorods.

  20. A large interconnecting network within hybrid MEH-PPV/TiO2 nanorod photovoltaic devices

    Zeng, T-W; Lin, Y-Y; Lo, H-H; Chen, C-W; Chen, C-H; Liou, S-C; Huang, H-Y; Su, W-F

    2006-01-01

    This is a study of hybrid photovoltaic devices based on TiO 2 nanorods and poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV). We use TiO 2 nanorods as the electron acceptors and conduction pathways. Here we describe how to develop a large interconnecting network within the photovoltaic device fabricated by inserting a layer of TiO 2 nanorods between the MEH-PPV:TiO 2 nanorod hybrid active layer and the aluminium electrode. The formation of a large interconnecting network provides better connectivity to the electrode, leading to a 2.5-fold improvement in external quantum efficiency as compared to the reference device without the TiO 2 nanorod layer. A power conversion efficiency of 2.2% under illumination at 565 nm and a maximum external quantum efficiency of 24% at 430 nm are achieved. A power conversion efficiency of 0.49% is obtained under Air Mass 1.5 illumination

  1. Hydrothermal Synthesis and Photocatalytic Property of β-Ga2O3 Nanorods

    Reddy, L. Sivananda; Ko, Yeong Hwan; Yu, Jae Su

    2015-09-01

    Gallium oxide (Ga2O3) nanorods were facilely prepared by a simple hydrothermal synthesis, and their morphology and photocatalytic property were studied. The gallium oxide hydroxide (GaOOH) nanorods were formed in aqueous growth solution containing gallium nitrate and ammonium hydroxide at 95 °C of growth temperature. Through the calcination treatment at 500 and 1000 °C for 3 h, the GaOOH nanorods were converted into single crystalline α-Ga2O3 and β-Ga2O3 phases. From X-ray diffraction analysis, it could be confirmed that a high crystalline quality of β-Ga2O3 nanorods was achieved by calcinating at 1000 °C. The thermal behavior of the Ga2O3 nanorods was also investigated by differential thermal analysis, and their vibrational bands were identified by Fourier transform infrared spectroscopy. In order to examine the photocatalytic activity of samples, the photodegradation of Rhodamine B solution was observed under UV light irradiation. As a result, the α-Ga2O3 and β-Ga2O3 nanorods exhibited high photodegeneration efficiencies of 62 and 79 %, respectively, for 180 min of UV irradiation time.

  2. Hydrothermal Synthesis and Photocatalytic Property of β-Ga2O3 Nanorods.

    Reddy, L Sivananda; Ko, Yeong Hwan; Yu, Jae Su

    2015-12-01

    Gallium oxide (Ga2O3) nanorods were facilely prepared by a simple hydrothermal synthesis, and their morphology and photocatalytic property were studied. The gallium oxide hydroxide (GaOOH) nanorods were formed in aqueous growth solution containing gallium nitrate and ammonium hydroxide at 95 °C of growth temperature. Through the calcination treatment at 500 and 1000 °C for 3 h, the GaOOH nanorods were converted into single crystalline α-Ga2O3 and β-Ga2O3 phases. From X-ray diffraction analysis, it could be confirmed that a high crystalline quality of β-Ga2O3 nanorods was achieved by calcinating at 1000 °C. The thermal behavior of the Ga2O3 nanorods was also investigated by differential thermal analysis, and their vibrational bands were identified by Fourier transform infrared spectroscopy. In order to examine the photocatalytic activity of samples, the photodegradation of Rhodamine B solution was observed under UV light irradiation. As a result, the α-Ga2O3 and β-Ga2O3 nanorods exhibited high photodegeneration efficiencies of 62 and 79 %, respectively, for 180 min of UV irradiation time.

  3. Influence of strain relaxation on the optical properties of InGaN/GaN multiple quantum well nanorods

    Wang, Q; Bai, J; Gong, Y P; Wang, T

    2011-01-01

    Optical investigation has been carried out on InGaN/GaN nanorod structures with different indium compositions, fabricated from InGaN/GaN multiple quantum well (MQW) epitaxial wafers using a self-organized nickel nano-mask and subsequent dry etching techniques. In comparison with the as-grown InGaN/GaN MQWs, the internal quantum efficiencies of the nanorods are significantly improved, in particular, for the green InGaN/GaN nanorods with a high indium composition, the internal quantum efficiency is enhanced by a factor of 8, much larger than the enhancement factor of 3.4 for the blue InGaN/GaN nanorods. X-ray reciprocal space mapping (RSM) measurements have been performed in order to quantitatively evaluate the stain relaxation in the nanorods, demonstrating that the majority of strain in InGaN/GaN MQWs can be relaxed as a result of fabrication into nanorods. The excitation-power-dependent photoluminescence measurements have also clearly shown that a significant reduction in the strain-induced quantum confined stark effect has occurred to the nanorod structures.

  4. Polarization Properties of Semiconductor Nanorod Heterostructures: From Single Particles to the Ensemble.

    Hadar, Ido; Hitin, Gal B; Sitt, Amit; Faust, Adam; Banin, Uri

    2013-02-07

    Semiconductor heterostructured seeded nanorods exhibit intense polarized emission, and the degree of polarization is determined by their morphology and dimensions. Combined optical and atomic force microscopy were utilized to directly correlate the emission polarization and the orientation of single seeded nanorods. For both the CdSe/CdS sphere-in-rod (S@R) and rod-in-rod (R@R), the emission was found to be polarized along the nanorod's main axis. Statistical analysis for hundreds of single nanorods shows higher degree of polarization, p, for R@R (p = 0.83), in comparison to S@R (p = 0.75). These results are in good agreement with the values inferred by ensemble photoselection anisotropy measurements in solution, establishing its validity for nanorod samples. On this basis, photoselection photoluminescence excitation anisotropy measurements were carried out providing unique information concerning the symmetry of higher excitonic transitions and allowing for a better distinction between the dielectric and the quantum-mechanical contributions to polarization in nanorods.

  5. Fabrication of novel biodegradable porous bone scaffolds based on amphiphilic hydroxyapatite nanorods

    Zheng, Xiaoyan; Hui, Junfeng [Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an 710069, Shaanxi, PR China2 (China); Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069, Shaanxi (China); Li, Hui; Zhu, Chenhui [Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an 710069, Shaanxi, PR China2 (China); Hua, Xiufu, E-mail: hua_xiufu@163.com [Department of Scientific Research and Development, Tsinghua University, Beijing 100084 (China); Ma, Haixia, E-mail: mahx@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069, Shaanxi (China); Fan, Daidi, E-mail: fandaidi@nwu.edu.cn [Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an 710069, Shaanxi, PR China2 (China)

    2017-06-01

    This paper describes a new synthetic strategy and biological application for novel amphiphilic hydroxyapatite (HAp) nanorods. The prepared HAp nanorods were able to be dispersed in water, ethyl alcohol and cyclohexane. The co-anchoring of the multidentate ligands of PEG 20000 and hydrophobic oleic acid (OA) on the rods' surfaces endowed them with excellent amphibious properties. Utilizing amphiphilic HAp nanorods with excellent biocompatibility as the inorganic phase, human-like collagen (HLC) as the organic phase and natural genipin as the cross-linker, optimal HLC/HAp porous scaffolds (HLC: HAp = 1:4, w/w) were fabricated. The compression stress and three-point bending strength of the scaffolds with pore diameters of 150 to 200 μm reached approximately 3.4 MPa and 5.4 MPa, respectively, and their porosity was 77.35 ± 3.75%. Cytological tests showed that HLC/HAp scaffolds could contribute to cell proliferation and differentiation. The results indicated that these novel amphiphilic HAp nanorods can be expected to become recognized as an excellent inorganic material for the porous scaffolds used in repairing bone and related applications. - Highlights: • A simple and effective hydrothermal method was developed for preparing uniform HAp nanorods with amphiphilic surfaces. • The synthesized amphiphilic HAp nanorods could be dispersed in water, ethyl alcohol or cyclohexane. • The prepared HLC/HAp porous scaffolds had good mechanical properties, biocompatibility and osteoconductive etc.

  6. Fabrication of novel biodegradable porous bone scaffolds based on amphiphilic hydroxyapatite nanorods

    Zheng, Xiaoyan; Hui, Junfeng; Li, Hui; Zhu, Chenhui; Hua, Xiufu; Ma, Haixia; Fan, Daidi

    2017-01-01

    This paper describes a new synthetic strategy and biological application for novel amphiphilic hydroxyapatite (HAp) nanorods. The prepared HAp nanorods were able to be dispersed in water, ethyl alcohol and cyclohexane. The co-anchoring of the multidentate ligands of PEG 20000 and hydrophobic oleic acid (OA) on the rods' surfaces endowed them with excellent amphibious properties. Utilizing amphiphilic HAp nanorods with excellent biocompatibility as the inorganic phase, human-like collagen (HLC) as the organic phase and natural genipin as the cross-linker, optimal HLC/HAp porous scaffolds (HLC: HAp = 1:4, w/w) were fabricated. The compression stress and three-point bending strength of the scaffolds with pore diameters of 150 to 200 μm reached approximately 3.4 MPa and 5.4 MPa, respectively, and their porosity was 77.35 ± 3.75%. Cytological tests showed that HLC/HAp scaffolds could contribute to cell proliferation and differentiation. The results indicated that these novel amphiphilic HAp nanorods can be expected to become recognized as an excellent inorganic material for the porous scaffolds used in repairing bone and related applications. - Highlights: • A simple and effective hydrothermal method was developed for preparing uniform HAp nanorods with amphiphilic surfaces. • The synthesized amphiphilic HAp nanorods could be dispersed in water, ethyl alcohol or cyclohexane. • The prepared HLC/HAp porous scaffolds had good mechanical properties, biocompatibility and osteoconductive etc.

  7. Structure and photoluminescence of boron and nitrogen co-doped carbon nanorods

    Wang, B.B. [College of Chemistry and Chemical Engineering, Chongqing University of Technology, 69 Hongguang Rd, Lijiatuo, Banan District, Chongqing 400054 (China); Gao, B. [College of Computer Science, Chongqing University, Chongqing 400044 (China); Chongqing Municipal Education Examinations Authority, Chongqing 401147 (China); Zhong, X.X., E-mail: xxzhong@sjtu.edu.cn [Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Shao, R.W.; Zheng, K. [Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124 (China)

    2016-07-15

    Graphical abstract: Boron- and nitrogen- doped carbon nanorods. - Highlights: • The co-doping of nitrogen and boron in carbon nanorods. • The doping mechanism of nitrogen and boron in carbon nanorods by plasma. • Photoluminescence properties of nitrogen- and boron-doped carbon nanorods. - Abstract: Boron and nitrogen doped carbon nanorods (BNCNRs) were synthesized by plasma-enhanced hot filament chemical vapor deposition, where methane, nitrogen and hydrogen were used as the reaction gases and boron carbide was the boron source. The results of scanning electron microscopy, micro-Raman spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy indicate that boron and nitrogen can be used as co-dopants in amorphous carbon nanorods. Combined with the characterization results, the doping mechanism was studied. The mechanism is used to explain the formation of different carbon materials by different methods. The photoluminescence (PL) properties of BNCNRs were studied. The PL results show that the BNCNRs generate strong green PL bands and weak blue PL bands, and the PL intensity lowered due to the doping of boron. The outcomes advance our knowledge on the synthesis and optical properties of carbon-based nanomaterials and contribute to the development of optoelectronic nanodevices based on nano-carbon mateirals.

  8. Facile synthesis of highly branched jacks-like ZnO nanorods and their applications in dye-sensitized solar cells

    Sudhagar, P. [Center for Next Generation Dye-sensitized Solar Cells, WCU Program Department of Energy Engineering, Hanyang University, Seongdong-gu, Seoul- 133 791 (Korea, Republic of); Kumar, R. Saravana [R and D Department of Physics, Kongunadu Arts and Science College, Coimbatore 641 029, Tamilnadu (India); Jung, June Hyuk; Cho, Woohyung [Center for Next Generation Dye-sensitized Solar Cells, WCU Program Department of Energy Engineering, Hanyang University, Seongdong-gu, Seoul- 133 791 (Korea, Republic of); Sathyamoorthy, R. [R and D Department of Physics, Kongunadu Arts and Science College, Coimbatore 641 029, Tamilnadu (India); Won, Jongok [Department of Chemistry, Sejong University, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Kang, Yong Soo, E-mail: kangys@hanyang.ac.kr [Center for Next Generation Dye-sensitized Solar Cells, WCU Program Department of Energy Engineering, Hanyang University, Seongdong-gu, Seoul- 133 791 (Korea, Republic of)

    2011-09-15

    Graphical abstract: -- Abstract: Highly branched, jacks-like ZnO nanorods architecture were explored as a photoanode in dye-sensitized solar cells, and their photovoltaic performance was compared with that of branch-free ZnO nanorods photoanodes. The highly branched network and large pores of the jacks-like ZnO nanorods electrodes enhances the charge transport, and electrolyte penetration. Thus, the jacks-like ZnO nanorods DSSCs render a higher conversion efficiency of {eta} = 1.82% (V{sub oc} = 0.59 V, J{sub sc} = 5.52 mA cm{sup -2}) than that of the branch-free ZnO nanorods electrodes ({eta} = 1.08%, V{sub oc} = 0.49 V, J{sub sc} = 4.02 mA cm{sup -2}). The incident photon-to-current conversion efficiency measurements reveal that the jacks-like ZnO nanorods DSSCs exhibit higher internal quantum efficiency ({approx}59.1%) than do the branch-free ZnO nanorods DSSC ({approx}52.5%). The charge transfer resistances at the ZnO/dye/electrolyte interfaces investigated using electrochemical impedance spectroscopy showed that the jacks-like ZnO nanorods DSSC had high charge transfer resistance and a slightly longer electron lifetime, thus improving the solar-cell performance.

  9. Facile synthesis of highly branched jacks-like ZnO nanorods and their applications in dye-sensitized solar cells

    Sudhagar, P.; Kumar, R. Saravana; Jung, June Hyuk; Cho, Woohyung; Sathyamoorthy, R.; Won, Jongok; Kang, Yong Soo

    2011-01-01

    Graphical abstract: -- Abstract: Highly branched, jacks-like ZnO nanorods architecture were explored as a photoanode in dye-sensitized solar cells, and their photovoltaic performance was compared with that of branch-free ZnO nanorods photoanodes. The highly branched network and large pores of the jacks-like ZnO nanorods electrodes enhances the charge transport, and electrolyte penetration. Thus, the jacks-like ZnO nanorods DSSCs render a higher conversion efficiency of η = 1.82% (V oc = 0.59 V, J sc = 5.52 mA cm -2 ) than that of the branch-free ZnO nanorods electrodes (η = 1.08%, V oc = 0.49 V, J sc = 4.02 mA cm -2 ). The incident photon-to-current conversion efficiency measurements reveal that the jacks-like ZnO nanorods DSSCs exhibit higher internal quantum efficiency (∼59.1%) than do the branch-free ZnO nanorods DSSC (∼52.5%). The charge transfer resistances at the ZnO/dye/electrolyte interfaces investigated using electrochemical impedance spectroscopy showed that the jacks-like ZnO nanorods DSSC had high charge transfer resistance and a slightly longer electron lifetime, thus improving the solar-cell performance.

  10. Reactive tunnel junctions in electrically driven plasmonic nanorod metamaterials

    Wang, Pan; Krasavin, Alexey V.; Nasir, Mazhar E.; Dickson, Wayne; Zayats, Anatoly V.

    2018-02-01

    Non-equilibrium hot carriers formed near the interfaces of semiconductors or metals play a crucial role in chemical catalysis and optoelectronic processes. In addition to optical illumination, an efficient way to generate hot carriers is by excitation with tunnelling electrons. Here, we show that the generation of hot electrons makes the nanoscale tunnel junctions highly reactive and facilitates strongly confined chemical reactions that can, in turn, modulate the tunnelling processes. We designed a device containing an array of electrically driven plasmonic nanorods with up to 1011 tunnel junctions per square centimetre, which demonstrates hot-electron activation of oxidation and reduction reactions in the junctions, induced by the presence of O2 and H2 molecules, respectively. The kinetics of the reactions can be monitored in situ following the radiative decay of tunnelling-induced surface plasmons. This electrically driven plasmonic nanorod metamaterial platform can be useful for the development of nanoscale chemical and optoelectronic devices based on electron tunnelling.

  11. Study on Photoelectric Properties of Composite Films of Graphene/Ti02 Nanorods

    JIN Guo-li

    2017-02-01

    Full Text Available TiOZ nanorods have large specific surface area and the ability of directional transmission electron, based on which can reduce recombination probability of light-generated electrons and holes,and improve the photoelectric conversion efficiency of DSSC. As graphene has low resistivity,good stability and excellent transparency,it can be introduced into anode film to improve the electronic transmission. The TiOZ nanorods were prepared by hydrothermal method,mixed with different quality of graphene. Its length range was 200-300 nm,with a diameter of about 20 nm. The porous graphene/TiOZ nanorods composite film were prepared by using electro- hydrodynamic technique(EHDand compositing TiOZ nanorods with different quality of grapheme. The photoelectric conversion efficiency of the DSSC device prepared with the photo-anode film with graphene mass content of 3 % was 4. 23 %,the photoelectric conversion efficiency increased by 36%,relative to that of no graphene doped TiOZ nanorods photo-anode film.

  12. Towards measuring quantum electrodynamic torque with a levitated nanorod

    Xu, Zhujing; Bang, Jaehoon; Ahn, Jonghoon; Hoang, Thai M.; Li, Tongcang

    2017-04-01

    According to quantum electrodynamics, quantum fluctuations of electromagnetic fields give rise to a zero-point energy that never vanishes, even in the absence of electromagnetic sources. The interaction energy will not only lead to the well-known Casimir force but will also contribute to the Casimir torque for anisotropic materials. We propose to use an optically levitated nanorod in vacuum and a birefringent substrate to experimentally investigate the QED torque. We have previously observed the libration of an optically levitated non-spherical nanoparticle in vacuum and found it to be an ultrasensitive torque sensor. A nanorod with a long axis of 300nm and a diameter of 60nm levitated in vacuum at 10 (- 8) torr will have a remarkable torque detection sensitivity on the order of 10 (- 28) Nm/ √Hz, which will be sufficient to detect the Casimir torque. This work is partially supported by the National Science Foundation under Grant No.1555035-PHY.

  13. High temperature structural and magnetic properties of cobalt nanorods

    Ait Atmane, Kahina [Univ. Paris Diderot, Sorbonne Paris Cite, ITODYS, UMR CNRS 7086, 15 rue J.-A. de Baief, 75205 Paris Cedex 13 (France); Zighem, Fatih [Laboratoire Leon Brillouin, CEA CNRS UMR 12, IRAMIS, CEA-Saclay, 91191 Gif sur Yvette (France); Soumare, Yaghoub [Univ. Paris Diderot, Sorbonne Paris Cite, ITODYS, UMR CNRS 7086, 15 rue J.-A. de Baief, 75205 Paris Cedex 13 (France); Ibrahim, Mona; Boubekri, Rym [Universite de Toulouse, LPCNO, INSA CNRS UMR 5215, 135 av. de Rangueil, 31077 Toulouse Cedex 4 (France); Maurer, Thomas [Laboratoire Leon Brillouin, CEA CNRS UMR 12, IRAMIS, CEA-Saclay, 91191 Gif sur Yvette (France); Margueritat, Jeremie [Univ. Paris Diderot, Sorbonne Paris Cite, ITODYS, UMR CNRS 7086, 15 rue J.-A. de Baief, 75205 Paris Cedex 13 (France); Piquemal, Jean-Yves, E-mail: jean-yves.piquemal@univ-paris-diderot.fr [Univ. Paris Diderot, Sorbonne Paris Cite, ITODYS, UMR CNRS 7086, 15 rue J.-A. de Baief, 75205 Paris Cedex 13 (France); Ott, Frederic; Chaboussant, Gregory [Laboratoire Leon Brillouin, CEA CNRS UMR 12, IRAMIS, CEA-Saclay, 91191 Gif sur Yvette (France); Schoenstein, Frederic; Jouini, Noureddine [LSPM, CNRS UPR 9001, Universite Paris XIII, Institut Galilee, 99 av. J.-B. Clement, 93430 Villetaneuse (France); Viau, Guillaume, E-mail: gviau@insa-toulouse.fr [Universite de Toulouse, LPCNO, INSA CNRS UMR 5215, 135 av. de Rangueil, 31077 Toulouse Cedex 4 (France)

    2013-01-15

    We present in this paper the structural and magnetic properties of high aspect ratio Co nanoparticles ({approx}10) at high temperatures (up to 623 K) using in-situ X ray diffraction (XRD) and SQUID characterizations. We show that the anisotropic shapes, the structural and texture properties are preserved up to 500 K. The coercivity can be modelled by {mu}{sub 0}H{sub C}=2(K{sub MC}+K{sub shape})/M{sub S} with K{sub MC} the magnetocrystalline anisotropy constant, K{sub shape} the shape anisotropy constant and M{sub S} the saturation magnetization. H{sub C} decreases linearly when the temperature is increased due to the loss of the Co magnetocrystalline anisotropy contribution. At 500 K, 50% of the room temperature coercivity is preserved corresponding to the shape anisotropy contribution only. We show that the coercivity drop is reversible in the range 300-500 K in good agreement with the absence of particle alteration. Above 525 K, the magnetic properties are irreversibly altered either by sintering or by oxidation. - Graphical abstract: We present in this paper the structural and magnetic properties of high aspect ratio Co nanorods ({approx}10) at high temperatures (up to 623 K) using in-situ X-ray diffraction and SQUID characterizations. We show that the anisotropic shapes, the structural and texture properties are preserved up to 500 K. Above 525 K, the magnetic properties are irreversibly altered either by sintering or by oxidation. Highlights: Black-Right-Pointing-Pointer Ferromagnetic Co nanorods are prepared using the polyol process. Black-Right-Pointing-Pointer The structural and texture properties of the Co nanorods are preserved up to 500 K. Black-Right-Pointing-Pointer The magnetic properties of the Co nanorods are irreversibly altered above 525 K.

  14. Superior photoelectrochemical properties of ZnO nanorods/poly(3-hexylthiophene) hybrid photoanodes

    Majumder, T.; Hmar, J. J. L.; Dhar, S.; Mondal, S. P.

    2017-06-01

    Photoelectrochemical properties of ZnO nanorods (ZnO NRs) and poly(3-hexylthiophene) (P3HT) polymer hybrid photoanodes have been studied. The hybrid photoanodes demonstrated higher photoconversion efficiency, incident photon to current conversion efficiency (IPCE) and lower interfacial resistance compared to pristine ZnO nanorods and P3HT based electrodes. The origin of superior photoelectrochemical properties of ZnO/P3HT photoanodes has been explained using carrier transport mechanism at semiconductor/electrolyte junction. The stability of ZnO NRs/P3HT photoanode has been demonstrated.

  15. Masticatory efficiency contributing to the improved dynamic postural balance: A cross-sectional study.

    Hwang, Hae-Yun; Choi, Jun-Seon; Kim, Hee-Eun

    2018-05-28

    To evaluate whether masticatory efficiency is associated with dynamic postural balance. Masticatory dysfunction can cause deterioration of general health due to nutritional imbalances, thereby negatively affecting postural balance. However, few studies have investigated the association between masticatory efficiency and postural balance. The masticatory efficiency of 74 participants was evaluated by calculating mixing ability index (MAI) using a wax cube. The timed up and go test (TUGT) was used to measure dynamic balance. Participants with an MAI above or below the median value of 1.05 were defined as having high or low masticatory efficiency, respectively. An independent samples t-test was used to identify significant differences in TUGT, according to masticatory efficiency. Analysis of covariance was performed to adjust for confounding factors. Logistic regression analysis was used to assess the correlation between masticatory efficiency and postural balance. The high masticatory efficiency group could complete the TUGT exercise approximately 1.67 seconds faster while maintaining the postural balance, compared to the low masticatory efficiency group (P = .005). Furthermore, the postural imbalance odds of the group with high mastication efficiency decreased by 0.14-fold, relative to the group with low mastication efficiency (95% confidence interval: 0.04-0.46). With some reservations about statistical power, the association found between masticatory efficiency and postural balance justifies further investigations to confirm the strength of the associations, and possibly to identify causal relationships between mastication and posture in old age. © 2018 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd.

  16. ZnO-Nanorod Dye-Sensitized Solar Cells: New Structure without a Transparent Conducting Oxide Layer

    Ming-Hong Lai

    2010-01-01

    Full Text Available Conventional nanorod-based dye-sensitized solar cells (DSSCs are fabricated by growing nanorods on top of a transparent conducting oxide (TCO, typically fluorine-doped tin oxide—FTO. The heterogeneous interface between the nanorod and TCO forms a source for carrier scattering. This work reports on a new DSSC architecture without a TCO layer. The TCO-less structure consists of ZnO nanorods grown on top of a ZnO film. The ZnO film replaced FTO as the TCO layer and the ZnO nanorods served as the photoanode. The ZnO nanorod/film structure was grown by two methods: (1 one-step chemical vapor deposition (CVD (2 two-step chemical bath deposition (CBD. The thicknesses of the nanorods/film grown by CVD is more uniform than that by CBD. We demonstrate that the TCO-less DSSC structure can operate properly as solar cells. The new DSSCs yield the best short-current density of 3.96 mA/cm2 and a power conversion efficiency of 0.73% under 85 mW/cm2 of simulated solar illumination. The open-circuit voltage of 0.80 V is markedly higher than that from conventional ZnO DSSCs.

  17. Hydrothermal synthesis of HoMn{sub 2}O{sub 5} nanorods and their size-dependent magnetic properties

    Lv, Yichao; Wu, Songping, E-mail: chwsp@scut.edu.cn; Xu, Rui

    2017-03-01

    The HoMn{sub 2}O{sub 5} nanorods were synthesized by a surfactant-assisted hydrothermal process. The length of nanorods is readily controllable with basically constant diameter. HoMn{sub 2}O{sub 5} nanorods show recognizable divagation at T{sub N}(Ho) of 13 K between FC and ZFC curve due to the contribution of the magnetic ordering of holmium. Size-dependent magnetic properties (i.e. a critical length for magnetization) of HoMn{sub 2}O{sub 5} nanorods can be ascribed to the competition between surface strain and uncompensated spin at the surface. - Highlights: • HoMn{sub 2}O{sub 5} nanorods were synthesized by a surfactant-assisted hydrothermal route. • HoMn{sub 2}O{sub 5} nanorods show recognizable divagation at T{sub N}(Ho) of 13 K between FC and ZFC. • Size-dependent magnetic properties of HoMn{sub 2}O{sub 5} nanorods can be observed.

  18. Mitigation Theme Report: Energy Efficiency : Contribution to the MCA4climate initiative

    de Visser, Erika; Blok, K.|info:eu-repo/dai/nl/07170275X

    2011-01-01

    Striving for energy efficiency means trying to obtain a certain result with a minimum of input (Schipper and Meyers, 1992; Blok, 2007). As energy is used to fulfil human needs, one may define the energy efficiency of an activity as the degree to which given human needs can be fulfilled with a

  19. Side-detecting optical fiber coated with Zn(OH)2 nanorods for ultraviolet sensing applications

    Azad, S.; Parvizi, R.; Sadeghi, E.

    2017-09-01

    This paper presents an improved coupling efficiency and side detecting of UV radiation induced by light scattering and luminescent features of Zn(OH)2 nanorods coated multimode optical fibers. Uniform and high density Zn(OH)2 nanorods were grown hydrothermally on the core of chemically etched multimode optical fibers. The prepared samples were characterized through x-ray diffraction patterns, scanning electron microscopy and photoluminescence spectroscopy. The detecting technique was based on the intensity modulation of the side coupled light through the Zn(OH)2 nanorods. A simple and cost-effective UV radiation detecting setup has been designed. Experimentally estimated coupling efficiency of the proposed setup was obtained near 11%. The proposed device exhibited stable and reversible responses with a fast rising and decaying time of about 1.4 s and 0.85 s, respectively.

  20. Double Fano resonances in plasmon coupling nanorods

    Liu, Fei; Jin, Jie

    2015-01-01

    Fano resonances are investigated in nanorods with symmetric lengths and side-by-side assembly. Single Fano resonance can be obtained by a nanorod dimer, and double Fano resonances are shown in nanorod trimers with side-by-side assembly. With transverse plasmon excitation, Fano resonances are caused by the destructive interference between a bright superradiant mode and dark subradiant modes. The bright mode originates from the electric plasmon resonance, and the dark modes originate from the magnetic resonances induced by near-field inter-rod coupling. Double Fano resonances result from double dark modes at different wavelengths, which are induced and tuned by the asymmetric gaps between the adjacent nanorods. Fano resonances show a high figure of merit and large light extinction in the periodic array of assembled nanorods, which can potentially be used in multiwavelength sensing in the visible and near-infrared regions. (paper)

  1. Stimulated emission from ZnO nanorods

    Hauschild, R.; Lange, H.; Priller, H.; Klingshirn, C.; Kalt, H. [Institut fuer Angewandte Physik, Universitaet Karlsruhe (T.H.), 76128 Karlsruhe (Germany); Kling, R. [Abteilung Halbleiterphysik, Universitaet Ulm, Albert-Einstein Allee 45, 89081 Ulm (Germany); Waag, A. [Institut fuer Halbleitertechnik, TU-Braunschweig, H.-Sommer-Str. 66, 38106 Braunschweig (Germany); Fan, H.J.; Zacharias, M. [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany)

    2006-03-15

    By means of time resolved spectroscopy we compare two samples of ZnO nanorods with respect to their suitability as stimulated emitters. In the case of narrow nanorods their wave guiding quality causes a suppression of exciton-exciton scattering whereas no laser emission is detectable. Unlike their narrow counterparts, wide nanorods not only benefit from a larger overlap of the guided mode with the gain medium but a variation in VLS growth results in gold nanoparticles being present at the bottom of nanorods. Consequently, laser emission from single wide rods is evidenced up to 150 K. In addition to experimental studies we carry out 3D numerical simulations of the electric field distribution to evaluate the influence of gold nanoparticles at the nanorod/substrate interface. This finite element analysis confirms that gold leads to an enhancement of confinement within the resonator. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Growth and characterization of iridium dioxide nanorods

    Chen, R.S.; Huang, Y.S.; Liang, Y.M.; Tsai, D.S.; Tiong, K.K.

    2004-01-01

    Conductive iridium dioxide (IrO 2 ) nanorods have been successfully grown on the Si(1 0 0) substrates via metalorganic chemical vapor deposition (MOCVD). A wedge-shaped morphology and naturally formed sharp tips are observed for IrO 2 nanorods using field-emission scanning electron microscopy (FESEM). High-resolution transmission electron microscopy (TEM) image and electron diffraction pattern show the growth of IrO 2 nanorods preferentially along c-axis. Structure and composition of IrO 2 nanorods have also been characterized using the techniques of Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. It is noted that the IrO 2 nanorods are self-mediated instead of the conventional vapor-liquid-solid (VLS) approach or catalyst-mediated method

  3. Increased Energy Efficiency in Slovenian Industry - A Contribution to the Kyoto Target

    Selan, B.; Urbancic, A.

    1998-01-01

    In Slovenia the actual fast growth of greenhouse emissions will require substantial efforts to fulfil the target set in Kyoto. The end-use emissions in the in the industrial sectors represented one third of the total CO 2 emissions in the country in 1996. The cost-effective potential in the sector for CO 2 emission reduction is significant. In the paper, the most important ongoing energy efficiency activities in the industrial sector are presented: information and awareness building, energy advising to larger industrial consumers, energy audition programme, demonstration programme of energy efficiency technologies, financial incentives for energy efficiency investment and the energy efficiency investment fund. A CO 2 tax has been in force since 1997. The results of an evaluation of energy efficiency strategies in industry in the frame of the project 'Integrated resource planning for the energy efficiency in Slovenia' are discussed from the viewpoint of greenhouse gases reduction targets set by Slovenia, and a brief information on the ongoing and expected post Kyoto activities and studies is given. The most important points of the future GHG reduction strategy related to industrial sector in Slovenia will be focused on intensified energy efficiency programme, increased combined heat and power production (CHP), and the effects of incentives through the CO 2 tax. (author)

  4. Synthesis and Photocatalytic Performance of RGO/ZnO Nanorod Composites

    LU Jia

    2016-12-01

    Full Text Available ZnO nanorods and RGO/ZnO nanorods composites were prepared by hydrothermal method. The influence of RGO content on the photocatalytic activity of RGO/ZnO nanorods composites was studied. ZnO nanorods and RGO/ZnO nanocomposites were characterized by X-ray diffraction (XRD, field emission electron microscopy (FESEM, X-ray photoelectron spectroscopy (XPS and diffuse reflectance UV-visible absorption spectroscopy techniques. The results show that RGO/ZnO samples are synthesized successfully. With different additions of GO, the RGO/ZnO samples obtained exhibit different absorption characteristics in visible light region. The photocatalytic results of using methyl orange (MO as the simulated pollutant show that RGO/ZnO nanorods composites exhibit high degradation efficiency under UV-Vis light illumination. The highest photocatalytic performance is obtained for RGO/ZnO composites when the mass ratio of RGO to ZnO is 3%. MO is almost completely degraded in 120min. RGO/ZnO also shows the visible-light-driven photocatalytic activity under visible light illumination (λ>400nm, and the maximum MO degradation efficiency in 180min can reach 26.2%, meanwhile, RGO/ZnO samples exhibit good photostability.

  5. Increasing the solar cell power output by coating with transition metal-oxide nanorods

    Kuznetsov, I.A.; Greenfield, M.J.; Mehta, Y.U.; Merchan-Merchan, W.; Salkar, G.; Saveliev, A.V.

    2011-01-01

    Highlights: → Nanoparticles enhance solar cell efficiency. → Solar cell power increase by nanorod coating. → Metal-oxide nanorods are prepared in flames. → Molybdenum oxide nanorods effectively scatter light on solar cell surface. → Scattering efficiency depends on coating density. -- Abstract: Photovoltaic cells produce electric current through interactions among photons from an ambient light source and electrons in the semiconductor layer of the cell. However, much of the light incident on the panel is reflected or absorbed without inducing the photovoltaic effect. Transition metal-oxide nanoparticles, an inexpensive product of a process called flame synthesis, can cause scattering of light. Scattering can redirect photon flux, increasing the fraction of light absorbed in the thin active layer of silicon solar cells. This research aims to demonstrate that the application of transition metal-oxide nanorods to the surface of silicon solar panels can enhance the power output of the panels. Several solar panels were coated with a nanoparticle-methanol suspension, and the power outputs of the panels before and after the treatment were compared. The results demonstrate an increase in power output of up to 5% after the treatment. The presence of metal-oxide nanorods on the surface of the coated solar cells is confirmed by electron microscopy.

  6. Dye-Sensitized Solar Cells with Anatase TiO2 Nanorods Prepared by Hydrothermal Method

    Ming-Jer Jeng

    2013-01-01

    Full Text Available The hydrothermal method provides an effective reaction environment for the synthesis of nanocrystalline materials with high purity and well-controlled crystallinity. In this work, we started with various sizes of commercial TiO2 powders and used the hydrothermal method to prepare TiO2 thin films. We found that the synthesized TiO2 nanorods were thin and long when smaller TiO2 particles were used, while larger TiO2 particles produced thicker and shorter nanorods. We also found that TiO2 films prepared by TiO2 nanorods exhibited larger surface roughness than those prepared by the commercial TiO2 particles. It was found that a pure anatase phase of TiO2 nanorods can be obtained from the hydrothermal method. The dye-sensitized solar cells fabricated with TiO2 nanorods exhibited a higher solar efficiency than those fabricated with commercial TiO2 nanoparticles directly. Further, triple-layer structures of TiO2 thin films with different particle sizes were investigated to improve the solar efficiency.

  7. Synthesis and in-depth analysis of highly ordered yttrium doped hydroxyapatite nanorods prepared by hydrothermal method and its mechanical analysis

    Nathanael, A. Joseph; Mangalaraj, D.; Hong, S.I.; Masuda, Y.

    2011-01-01

    In this study, undoped and yttrium (Y) doped nanocrystalline hydroxyapatite crystals were synthesized by the hydrothermal method at 180 °C for 24 h. Highly ordered and oriented hydroxyapatite (HAp) nanorods were prepared by yttrium doping and their nanostructure and physical properties were compared with those of undoped HAp rods. FESEM images showed that the doping with Y ions reduced the diameter (from 25 nm to 15 nm) and increased the length (from 95 nm to 115 nm) of the synthesized rods. The aspect ratio of the undoped and Y-doped nanorods were calculated to be 4.303 (SD = 0.0959) and 7.61 (SD = 0.0355), respectively. Specific surface area (SSA) analysis showed that SSA also increased from 66.74 m 2 /g to 68.57 m 2 /g with the addition of yttrium. Y-doped HAp nanorod reinforced HMWPE composites displayed the better mechanical performance than those reinforced with pure HAp nanorods. The possible strengthening of nanorods and the increase of SSA due to the reduction in the size of nanorods in the presence of yttrium may have contributed to the strengthening of Y-doped HAp/HMWPE composites. - Graphical Abstract: Highly ordered and oriented yttrium doped hydroxyapatite (HAp) nanorods were prepared by hydrothermal method. For undoped HAp the average length of the nanorod is 95 nm with mean diameter of 24 nm and for a Y doped nanorod the average length is ∼ 115 nm and the mean diameter is 15 nm. Mechanical analysis was carried out by polymer/nanoparticle composite method. Highlights: ► Yttrium doped hydroxyapatite nanorods were prepared by hydrothermal method. ► The nanorods have highly uniform size distribution. ► Yttrium substitution and nanostructure formation was confirmed by careful analysis. ► Mechanical strength was analyzed by polymer nanoparticle reinforcement method.

  8. Electrochemical characteristics of bundle-type silicon nanorods as an anode material for lithium ion batteries

    Nguyen, Si Hieu; Lim, Jong Choo; Lee, Joong Kee

    2012-01-01

    Highlights: ► A metal-assisted chemical etching technique was performed on Si thin films. ► The etching process resulted in the formation of bundle-type Si nanorods. ► The morphology of Si electrodes closely relate to electrochemical characteristics. - Abstract: In order to prepare bundle-type silicon nanorods, a silver-assisted chemical etching technique was used to modify a 1.6 μm silicon thin film, which was deposited on Cu foil by Electron Cyclotron Resonance Plasma Enhanced Chemical Vapor Deposition. The bundle-type silicon nanorods on Cu foil were employed as anodes for a lithium secondary battery, without further treatment. The electrochemical characteristics of the pristine silicon thin film anodes and the bundle-type silicon nanorod anodes are different from one another. The electrochemical performance of the bundle-type silicon nanorod anodes exceeded that of the pristine Si thin film anodes. The specific capacity of the bundle-type silicon nanorod anodes is much higher than 3000 mAh g −1 at the first charge (Li insertion) cycle. The coulombic efficiency of bundle-type silicon anodes was stable at more than 97%, and the charge capacity remained at 1420 mAh g −1 , even after 100 cycles of charging and discharging. The results from the differential voltage analysis showed a side reaction at around 0.44–0.5 V, and the specific potential of this side reaction decreased after each cycle. The apparent diffusion coefficients of the two anode types were in the range of 10 −13 –10 −16 cm 2 s −1 in the first cycle. In subsequent charge cycles, these values for the silicon thin film anodes and the silicon nanorod bundle anode were approximately 10 −12 –10 −14 and 10 −13 –10 −15 cm 2 s −1 , respectively.

  9. Induction of cell death in a glioblastoma line by hyperthermic therapy based on gold nanorods

    Fernandez Cabada T

    2012-03-01

    Full Text Available Tamara Fernandez Cabada1,2,*, Cristina Sanchez Lopez de Pablo1,3,*, Alberto Martinez Serrano2, Francisco del Pozo Guerrero1,3, Jose Javier Serrano Olmedo1,3,*, Milagros Ramos Gomez1–3,* 1Centre for Biomedical Technology, Universidad Politecnica de Madrid, Madrid, Spain; 2Centre for Molecular Biology, "Severo Ochoa" Universidad Autonoma de Madrid, Madrid, Spain; 3Biomedical Research Networking Center in Bioengineering Biomaterials and Nanomedicine (CIBER-bbn, Zaragoza, Spain.*These authors contributed equally to this workBackground: Metallic nanorods are promising agents for a wide range of biomedical applications. In this study, we developed an optical hyperthermia method capable of inducing in vitro death of glioblastoma cells.Methods: The procedure used was based on irradiation of gold nanorods with a continuous wave laser. This kind of nanoparticle converts absorbed light into localized heat within a short period of time due to the surface plasmon resonance effect. The effectiveness of the method was determined by measuring changes in cell viability after laser irradiation of glioblastoma cells in the presence of gold nanorods.Results: Laser irradiation in the presence of gold nanorods induced a significant decrease in cell viability, while no decrease in cell viability was observed with laser irradiation or incubation with gold nanorods alone. The mechanism of cell death mediated by gold nanorods during photothermal ablation was analyzed, indicating that treatment compromised the integrity of the cell membrane instead of initiating the process of programmed cell death.Conclusion: The use of gold nanorods in hyperthermal therapies is very effective in eliminating glioblastoma cells, and therefore represents an important area of research for therapeutic development.Keywords: laser irradiation, photothermal therapy, surface plasmon resonance, cancer

  10. Convergent evolution towards high net carbon gain efficiency contributes to the shade tolerance of palms (Arecaceae)

    Ma, Ren Yi; Zhang, Jiao Lin; Cavaleri, Molly A.; Sterck, Frank; Strijk, J.S.; Cao, Kun Fang

    2015-01-01

    Most palm species occur in the shaded lower strata of tropical rain forests, but how their traits relate to shade adaptation is poorly understood. We hypothesized that palms are adapted to the shade of their native habitats by convergent evolution towards high net carbon gain efficiency (CGEn),

  11. Efficiency of the emission trading. A contribution to the climate protection law

    Frenz, Walter

    2014-01-01

    The contribution discusses the following topics: Inclusion of additional sectors into the emission trading: road traffic and sea traffic, the stepwise realization and difficulties; the failed inclusion of air traffic, rigid penalties in case of violation of the fee delivery, thread for the complete mechanism, over-compliance in Germany and international perspectives.

  12. Mitochondrial abundance and efficiency contribute to lean color of dark cutting beef

    Beef carcasses exhibiting four levels of dark cutting severity (DCS): Severe, Moderate, Mild, and Shady were compared to Control carcasses to investigate biochemical traits contributing to the dark cutting condition. Color attributes of Longissimus lumborum (LL) were measured after grading and duri...

  13. Size-controlled InGaN/GaN nanorod LEDs with an ITO/graphene transparent layer

    Shim, Jae-Phil; Seong, Won-Seok; Min, Jung-Hong; Kong, Duk-Jo; Seo, Dong-Ju; Kim, Hyung-jun; Lee, Dong-Seon

    2016-11-01

    We introduce ITO on graphene as a current-spreading layer for separated InGaN/GaN nanorod LEDs for the purpose of passivation-free and high light-extraction efficiency. Transferred graphene on InGaN/GaN nanorods effectively blocks the diffusion of ITO atoms to nanorods, facilitating the production of transparent ITO/graphene contact on parallel-nanorod LEDs, without filling the air gaps, like a bridge structure. The ITO/graphene layer sufficiently spreads current in a lateral direction, resulting in uniform and reliable light emission observed from the whole area of the top surface. Using KOH treatment, we reduce series resistance and reverse leakage current in nanorod LEDs by recovering the plasma-damaged region. We also control the size of the nanorods by varying the KOH treatment time and observe strain relaxation via blueshift in electroluminescence. As a result, bridge-structured LEDs with 8 min of KOH treatment show 15 times higher light-emitting efficiency than with 2 min of KOH treatment.

  14. Controlled synthesis of ZnO branched nanorod arrays by hierarchical solution growth and application in dye-sensitized solar cells

    Fang Xiaoming; Peng Lihua; Shang Xiaoying; Zhang Zhengguo

    2011-01-01

    We demonstrate the controlled synthesis of ZnO branched nanorod arrays on fluorine-doped SnO 2 -coated glass substrates by the hierarchical solution growth method. In the secondary growth, the concentration of Zn(NO 3 ) 2 /hexamethylenetetramine plays an important role in controlling the morphology of the branched nanorod arrays, besides that of diaminopropane used as a structure-directing agent to induce the growth of branches. The population density and morphology of the branched nanorod arrays depend on those of the nanorod arrays obtained from the primary growth, which can be modulated though the concentration of Zn(NO 3 ) 2 /hexamethylenetetramine in the primary growth solution. The dye-sensitized ZnO branched nanorod arrays exhibit much stronger optical absorption as compared with its corresponding primary nanorod arrays, suggesting that the addition of the branches improves light harvesting. The dye-sensitized solar cell based on the optimized ZnO branched nanorod array reaches a conversion efficiency of 1.66% under the light radiation of 1000 W/m 2 . The branched nanorod arrays can also be applied in other application fields of ZnO.

  15. Rapid green synthesis of silver nanoparticles and nanorods using Piper nigrum extract

    Mohapatra, Bandita; Kuriakose, Sini; Mohapatra, Satyabrata

    2015-01-01

    Highlights: • Silver nanorods were synthesized by photoreduction using Piper nigrum extract. • The morphological and structural properties were studied by XRD and AFM. • Silver nanoparticles were formed at lower AgNO 3 concentration. • Increase in AgNO 3 concentration resulted in formation of silver nanorods. - Abstract: We report sun light driven rapid green synthesis of stable aqueous dispersions of silver nanoparticles and nanorods at room temperature using photoreduction of silver ions with Piper nigrum extract. Silver nanoparticles were formed within 3 min of sun light irradiation following addition of Piper nigrum extract to the AgNO 3 solution. The effects of AgNO 3 concentration and irradiation time on the formation and plasmonic properties of biosynthesized silver nanoparticles were studied using UV–visible absorption spectroscopy. The morphology and structure of silver nanoparticles were well characterized by atomic force microscopy (AFM) and X-ray diffraction (XRD). The size of Ag nanoparticles increased with increase in irradiation time, leading to the formation of anisotropic nanostructures. Increasing the AgNO 3 concentration resulted in the formation of Ag nanorods. UV–visible absorption studies revealed the presence of surface plasmon resonance (SPR) peaks which red shift and broaden with increasing AgNO 3 concentration. We have demonstrated a facile, energy efficient and rapid green synthetic route to synthesize stable aqueous dispersions of silver nanoparticles and nanorods

  16. Rapid green synthesis of silver nanoparticles and nanorods using Piper nigrum extract

    Mohapatra, Bandita [Multifunctional Nanomaterials Laboratory, School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110078 (India); Kuriakose, Sini [Multifunctional Nanomaterials Laboratory, School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110078 (India); School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110078 (India); Mohapatra, Satyabrata, E-mail: smiuac@gmail.com [Multifunctional Nanomaterials Laboratory, School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110078 (India); School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110078 (India)

    2015-07-15

    Highlights: • Silver nanorods were synthesized by photoreduction using Piper nigrum extract. • The morphological and structural properties were studied by XRD and AFM. • Silver nanoparticles were formed at lower AgNO{sub 3} concentration. • Increase in AgNO{sub 3} concentration resulted in formation of silver nanorods. - Abstract: We report sun light driven rapid green synthesis of stable aqueous dispersions of silver nanoparticles and nanorods at room temperature using photoreduction of silver ions with Piper nigrum extract. Silver nanoparticles were formed within 3 min of sun light irradiation following addition of Piper nigrum extract to the AgNO{sub 3} solution. The effects of AgNO{sub 3} concentration and irradiation time on the formation and plasmonic properties of biosynthesized silver nanoparticles were studied using UV–visible absorption spectroscopy. The morphology and structure of silver nanoparticles were well characterized by atomic force microscopy (AFM) and X-ray diffraction (XRD). The size of Ag nanoparticles increased with increase in irradiation time, leading to the formation of anisotropic nanostructures. Increasing the AgNO{sub 3} concentration resulted in the formation of Ag nanorods. UV–visible absorption studies revealed the presence of surface plasmon resonance (SPR) peaks which red shift and broaden with increasing AgNO{sub 3} concentration. We have demonstrated a facile, energy efficient and rapid green synthetic route to synthesize stable aqueous dispersions of silver nanoparticles and nanorods.

  17. Formation of gold nanorods and gold nanorod films for surface-enhanced Raman scattering spectroscopy

    Trotsyuk, L.L.; Kulakovich, O.S.; Shabunya-Klyachkovskaya, E.V.; Gaponenko, S.V.; Vashchenko, S.V.

    2016-01-01

    The formation of gold nanorods as well as thin films prepared via electrostatic deposition of gold nanorods has been investigated. The obtained gold nanorods films have been used as substrates for the surface-enhanced Raman scattering analysis of sulfur-free organic molecules mitoxantrone and malachite green as well as inorganic malachite microcrystals for the first time. The additional modification of films with L-cysteine allows one to significantly extend the use of gold nanorods for the surface-enhanced Raman scattering analysis. (authors)

  18. Vertically aligned Ta3N5 nanorod arrays for solar-driven photoelectrochemical water splitting

    Li, Yanbo

    2012-09-18

    A vertically aligned Ta3N5 nanorod photoelectrode is fabricated by through-mask anodization and nitridation for water splitting. The Ta3N5 nanorods, working as photoanodes of a photoelectrochemical cell, yield a high photocurrent density of 3.8 mA cm -2 at 1.23 V versus a reversible hydrogen electrode under AM 1.5G simulated sunlight and an incident photon-to-current conversion efficiency of 41.3% at 440 nm, one of the highest activities reported for photoanodes so far. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Vertically aligned Ta3N5 nanorod arrays for solar-driven photoelectrochemical water splitting

    Li, Yanbo; Takata, Tsuyoshi; Cha, Dong Kyu; Takanabe, Kazuhiro; Minegishi, Tsutomu; Kubota, Jun; Domen, Kazunari

    2012-01-01

    A vertically aligned Ta3N5 nanorod photoelectrode is fabricated by through-mask anodization and nitridation for water splitting. The Ta3N5 nanorods, working as photoanodes of a photoelectrochemical cell, yield a high photocurrent density of 3.8 mA cm -2 at 1.23 V versus a reversible hydrogen electrode under AM 1.5G simulated sunlight and an incident photon-to-current conversion efficiency of 41.3% at 440 nm, one of the highest activities reported for photoanodes so far. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Near infrared photodetector based on polymer and indium nitride nanorod organic/inorganic hybrids

    Lai, Wei-Jung; Li, Shao-Sian; Lin, Chih-Cheng; Kuo, Chun-Chiang; Chen, Chun-Wei; Chen, Kuei-Hsien; Chen, Li-Chyong

    2010-01-01

    We propose a nanostructured near infrared photodetector based on indium nitride (InN) nanorod/poly(3-hexylthiophene) hybrids. The current-voltage characteristic of the hybrid device demonstrates the typical p-n heterojunction diode behavior, consisting of p-type polymer and n-type InN nanorods. The device shows a photoresponse range of 900-1260 nm under various reverse biases. An external quantum efficiency of 3.4% at 900 nm operated at -10 V reverse bias was obtained, which is comparable with devices based on lead sulfide and lead selenide hybrid systems.

  1. Measurements of extreme orientation-dependent temperature increase around an irradiated gold nanorod

    Ma, Haiyan; Bendix, Pól Martin; Oddershede, Lene Broeng

    2012-01-01

    this system and is generally applicable to any irradiated nanoparticle system. The nanorods are irradiated with a tightly focused laser beam at a wavelength of 1064 nm where biological matter exhibits a minimum in absorption. By controlling the polarization of the laser light we show that the absorption...... of light by the nanorod and the corresponding dissipated heat strongly depends on the orientation of the nanorod with respect to the polarization. Finally, by comparing to spherical gold nanoparticles, we demonstrate how a change in shape, from spherical to rod like, leads to a dramatic enhancement......When irradiated at its resonance frequency, a metallic nanoparticle efficiently converts the absorbed energy into heat which is locally dissipated. This effect can be used in photothermal treatments, e.g., of cancer cells. However, to fully exploit the functionality of metallic nanoparticles...

  2. The effects of surface stripping ZnO nanorods with argon bombardment

    Barnett, Chris J; Kryvchenkova, Olga; Maffeis, Thierry G G; Cobley, Richard J; Smith, Nathan A; Kelleher, Liam

    2015-01-01

    ZnO nanorods are used in devices including field effects transistors, piezoelectric transducers, optoelectronics and gas sensors. However, for efficient and reproducible device operation and contact behaviour, surface contaminants must be removed or controlled. Here we use low doses of argon bombardment to remove surface contamination and make reproducible lower resistance contacts. Higher doses strip the surface of the nanorods allowing intrinsic surface measurements through a cross section of the material. Photoluminescence finds that the defect distribution is higher at the near-surface, falling away in to the bulk. Contacts to the n-type defect-rich surface are near-Ohmic, whereas stripping away the surface layers allows more rectifying Schottky contacts to be formed. The ability to select the contact type to ZnO nanorods offers a new way to customize device behaviour. (paper)

  3. Nanorods and nanoparticles of titanium dioxide and their use in dye sensitized solar cells

    Govindaraj, R., E-mail: isrogovindaraj@gmail.com; Magesh, M.; Senthil Pandian, M.; Ramasamy, P. [Department of Physics, Research Centre, SSN College of Engineering, Kalavakkam, Chennai, Tamilnadu-603 110 (India); Mukhopadhyay, Sumita [Centre of Excellence for Green Energy and sensor systems, IIEST, Howrah, West Bengal-711 103 (India)

    2016-05-23

    Mesoporous TiO{sub 2} nanorods/nanorods were successfully synthesized by hydrothermal process at 170 °C for 72 hr. The powder X-ray diffraction pattern shows large fraction of anatase phase with good crystalline behavior of the prepared materials. The specific surface area and pore volume of the synthesized material are about 84.83 m{sup 2}/g and 0.1316 cc/g respectively. The morphological results show that the TiO{sub 2} nanorods had diameter of ~ 25 nm and the length of ~ 80 nm. The nanoparticles have 20 nm in size. The current-voltage curve shows that the synthesized TiO{sub 2} nanostructure results in 36.7 % higher solar cell efficiency than commercial P25.

  4. Fabrication of TiO2 nanorod assembly grafted rGO (rGO@TiO2-NR) hybridized flake-like photocatalyst

    Lv, Kangle; Fang, Shun; Si, Lingling; Xia, Yang; Ho, Wingkei; Li, Mei

    2017-01-01

    To efficiently separate the photo-generated electron-hole pairs of TiO2 hybrid, anatase TiO2 nanorod assembly grafted reduced graphene oxides (rGO@TiO2-NR) hybrid was successfully fabricated using potassium titanium oxalate (PTO) and graphene oxides (GO) as starting materials and diethylene glycol (DEG) as reductant. The effect of GO content on the structure and photocatalytic activity of rGO@TiO2-NR composite was systematically studied. Results show that, in the absence of GO, only TiO2 microsphere assembly is obtained from TiO2 nanorods. The presence of GO results in the formation of a flake-like TiO2-nanorod-assembled grafted rGO hybrid. The photocatalytic activity of rGO@TiO2-NR composite increases first and then decreases with increase in the amount of GO from 0 wt.% to 10 wt.%. The hybridized S4 sample prepared with 4 wt.% GO possesses the highest photocatalytic activity with a constant rate of 0.039 min-1 in the photocataytic degradation of Brilliant X-3B dye (X3B); this sample was enhanced more than three times when compared with pure TiO2 sample (0.012 min-1). The enhanced photocatalytic activity of the rGO@TiO2-NR hybrid was attributed to the strong interaction between TiO2 nanorods and rGO. The unique hierarchical structure of 1D nanorod assembly TiO2-rGO flakes facilitates the injection and transfer of photo-generated electrons from TiO2 to graphene, thus retarding the recombination of electron-hole pairs and enhancing the photocatalytic activity. The enlarged BET surface areas, not only increasing the number of active sites, but also facilitating the adsorption of the dye, and improved light-harvesting ability also contribute to the enhanced photoreactivity of rGO@TiO2-NR hybrid.

  5. Cell wall composition contributes to the control of transpiration efficiency in Arabidopsis thaliana.

    Liang, Yun-Kuan; Xie, Xiaodong; Lindsay, Shona E; Wang, Yi Bing; Masle, Josette; Williamson, Lisa; Leyser, Ottoline; Hetherington, Alistair M

    2010-11-01

    To identify loci in Arabidopsis involved in the control of transpirational water loss and transpiration efficiency (TE) we carried out an infrared thermal imaging-based screen. We report the identification of a new allele of the Arabidopsis CesA7 cellulose synthase locus designated AtCesA7(irx3-5) involved in the control of TE. Leaves of the AtCesA7(irx3-5) mutant are warmer than the wild type (WT). This is due to reduced stomatal pore widths brought about by guard cells that are significantly smaller than the WT. The xylem of the AtCesA7(irx3-5) mutant is also partially collapsed, and we suggest that the small guard cells in the mutant result from decreased water supply to the developing leaf. We used carbon isotope discrimination to show that TE is increased in AtCesA7(irx3-5) when compared with the WT. Our work identifies a new class of genes that affects TE and raises the possibility that other genes involved in cell wall biosynthesis will have an impact on water use efficiency. © 2010 The Authors. The Plant Journal © 2010 Blackwell Publishing Ltd.

  6. Quasi-Topotactic Transformation of FeOOH Nanorods to Robust Fe2O3 Porous Nanopillars Triggered with a Facile Rapid Dehydration Strategy for Efficient Photoelectrochemical Water Splitting.

    Liao, Aizhen; He, Huichao; Tang, Lanqin; Li, Yichang; Zhang, Jiyuan; Chen, Jiani; Chen, Lan; Zhang, Chunfeng; Zhou, Yong; Zou, Zhigang

    2018-03-28

    A facile rapid dehydration (RD) strategy is explored for quasi-topotactic transformation of FeOOH nanorods to robust Fe 2 O 3 porous nanopillars, avoiding collapse, shrink, and coalescence, and compared with a conventional treatment route. Additionally, the so-called RD process is capable of generating a beneficial porous structure for photoelectrochemical water oxidation. The obtained RD-Fe 2 O 3 photoanode exhibits a photocurrent density as high as 2.0 mA cm -2 at 1.23 V versus reversible hydrogen electrode (RHE) and a saturated photocurrent density of 3.5 mA cm -2 at 1.71 V versus RHE without any cocatalysts, which is about 270% improved photocurrent density over Fe 2 O 3 with the conventional temperature-rising route (0.75 mA cm -2 at 1.23 V vs RHE and 1.48 mA cm -2 at 1.71 V vs RHE, respectively). The enhanced photocurrent on RD-Fe 2 O 3 is attributed to a synergistic effect of the following factors: (i) preservation of single crystalline nanopillars decreases the charge-carrier recombination; (ii) formation of long nanopillars enhances light harvesting; and (iii) the porous structure shortens the hole transport distance from the bulk material to the electrode-electrolyte interface.

  7. The contribution of energy efficiency and renewability to the reduction of CO2 emissions

    Paredes, J.A.; Mateo, I.

    1995-01-01

    The European Commission has proposed a series of measures, among which the imposition of a tax on the consumption of energy and CO 2 emissions. Different organizations, among them Eurelectric, have opposed this tax, arguing that there exist alternative solutions, such as the adoption of voluntary commitments between companies/national governments, to reduce CO 2 emissions and which at the same time have a much lower cost/benefit ratio: the effects of the increased use of natural gas in electricity generation, improvements in energy efficiency and the promotion and development of cogeneration and renewable energies on CO 2 emissions on a national level (Spain), as well as applications of the same principles within a particular company (Union Fenosa). 3 tabs

  8. Low temperature synthesis of Zn{sub 2}GeO{sub 4} nanorods and their photoluminescence

    Tsai, Meng-Yen [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Instrument Technology Research Center, National Applied Research Laboratories, Hsinchu 300, Taiwan (China); Huang, Sheng-Hsin [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Perng, Tsong-Pyng, E-mail: tpperng@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Department of Chemical Engineering and Materials Science, Yuan Ze University, Chungli 320, Taiwan (China)

    2013-04-15

    Zn{sub 2}GeO{sub 4} nanorods were synthesized using a simple reflux method. The product with 0.05 M Zn{sub 2}GeO{sub 4} is an aggregation of short nanorods with the diameter ranging from 30 to 50 nm. If the Zn{sub 2}GeO{sub 4} molarity was increased, the nanorods became longer and aggregated as bundles. An intense white-bluish photoluminescence (PL) was observed from these nanorods, and the PL band can be dissolved into four Gaussian peaks that are associated with the native defects. Since the PL intensity of the nanorods is comparable to that of sintered particles, this reflux method provides a time- and energy-efficient route to prepare Zn{sub 2}GeO{sub 4} phosphor. -- Highlights: ► Zn{sub 2}GeO{sub 4} nanorods were prepared by a simple refluxing method at low temperature without any surfactants. ► The morphologies and crystal structures of Zn{sub 2}GeO{sub 4} growth were studied from beginning to the end (0 min to 3 h). ► The photoluminescence of Zn{sub 2}GeO{sub 4} synthesized by different methods was studied.

  9. Ag nanoparticles-decorated ZnO nanorod array on a mechanical flexible substrate with enhanced optical and antimicrobial properties

    Chen, Yi; Tse, Wai Hei; Chen, Longyan; Zhang, Jin

    2015-03-01

    Heteronanostructured zinc oxide nanorod (ZnO NR) array are vertically grown on polydimethylsiloxane (PDMS) through a hydrothermal method followed by an in situ deposition of silver nanoparticles (Ag NPs) through a photoreduction process. The Ag-ZnO heterostructured nanorods on PDMS are measured with an average diameter of 160 nm and an average length of 2 μm. ZnO NRs measured by high-resolution transmission electron microscope (HRTEM) shows highly crystalline with a lattice fringe of 0.255 nm, which corresponds to the (0002) planes in ZnO crystal lattice. The average diameter of the Ag NPs in situ deposited on the ZnO NRs is estimated at 22 ± 2 nm. As compared to the bare ZnO NRs, the heterostructured Ag-ZnO nanorod array shows enhanced ultraviolet (UV) absorption at 440 nm, and significant emission in the visible region (λem = 542 nm). In addition, the antimicrobial efficiency of Ag-ZnO heterostructured nanorod array shows obvious improvement as compared to bare ZnO nanorod array. The cytotoxicity of ZnO nanorod array with and without Ag NPs was studied by using 3 T3 mouse fibroblast cell line. No significant toxic effect is imposed on the cells.

  10. Iron oxyhydroxide nanorods with high electrochemical reactivity as a sensitive and rapid determination platform for 4-chlorophenol

    Zhang, Yuanyuan [Key Laboratory for Material Chemistry of Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Britton Chance Center for Biomedical Photonics at Wuhan, National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Cheng, Qin; Zheng, Meng [Key Laboratory for Material Chemistry of Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Liu, Xin [Britton Chance Center for Biomedical Photonics at Wuhan, National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Wu, Kangbing, E-mail: kbwu@hust.edu.cn [Key Laboratory for Material Chemistry of Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2016-04-15

    Highlights: • Prepared FeOOH nanorods exhibited high reactivity toward the oxidation of 4-CP. • Response signals and detection sensitivity of 4-CP increased greatly by FeOOH. • Highly-sensitive and rapid determination platform was developed for 4-CP. • Practical application in water samples was studied, and the accuracy was good. - Abstract: Iron oxyhydroxide (FeOOH) nanorods were prepared through solvothermal reaction, and characterized using Raman spectroscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy and scanning electron microscopy. Thereafter, the prepared FeOOH nanorods were used as sensing material to construct a novel detection platform for 4-chlorophenol (4-CP). The electrochemical behaviors of 4-CP were studied, and the oxidation peak currents increased greatly on the surface of FeOOH nanorods. The signal enhancement mechanism was studied for 4-CP, and it was found that the prepared FeOOH nanorods remarkably improved the electron transfer ability and surface adsorption efficiency of 4-CP. The influences of pH value, amount of FeOOH nanorods and accumulation time were examined. As a result, a highly-sensitive electrochemical method was developed for the rapid determination of 4-CP. The linear range was from 10 to 500 nM, and the detection limit was 3.2 nM. It was used in different water samples, and the results consisted with the values that obtained by high-performance liquid chromatography.

  11. Unusual photoluminescence properties of vertically aligned InN nanorods grown by plasma-assisted molecular-beam epitaxy

    Shen, C.H.; Chen, H.Y.; Lin, H.W.; Wu, C.Y.; Gwo, S.; Klochikhin, A.A.; Davydov, V.Yu.

    2007-01-01

    We report the unusual photoluminescence (PL) properties of vertically aligned InN nanorod arrays grown on Si(111) with a Si 3 N 4 buffer layer. The optimum growth conditions of InN nanorods are obtained by controlling the III/V ratio and the growth temperature. Structural characterization by X-ray diffraction and scanning electron microscopy indicates that individual nanorods are wurtzite InN single crystals with the growth direction along the c-axis. Near-infrared PL from InN nanorods is clearly observed at room temperature. However, in comparison to the PL from InN epitaxial films, the PL from InN nanorods is significantly lower in efficiency and exhibit anomalous temperature dependence. We propose that these unusual PL properties are results of considerable structural disorder (especially for the low-temperature grown InN nanorods) and strong surface electron accumulation effect. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Low-temperature growth of well-aligned zinc oxide nanorod arrays on silicon substrate and their photocatalytic application

    Azam A

    2014-04-01

    Full Text Available Ameer Azam,1 Saeed Salem Babkair21Center of Nanotechnology, King Abdulaziz University, Jeddah, Saudi Arabia; 2Center of Nanotechnology, Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, Saudi ArabiaAbstract: Well-aligned and single-crystalline zinc oxide (ZnO nanorod arrays were grown on silicon (Si substrate using a wet chemical route for the photodegradation of organic dyes. Structural analysis using X-ray diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction confirmed the formation of ZnO nanorods grown preferentially oriented in the (001 direction and with a single phase nature with a wurtzite structure. Field emission scanning electron microscopy and transmission electron microscopy micrographs showed that the length and diameter of the well-aligned rods were about ~350–400 nm and ~80–90 nm, respectively. Raman scattering spectra of ZnO nanorod arrays revealed the characteristic E2 (high mode that is related to the vibration of oxygen atoms in the wurtzite ZnO. The photodegradation of methylene blue (MB using ZnO nanorod arrays was performed under ultraviolet light irradiation. The results of photodegradation showed that ZnO nanorod arrays were capable of degrading ~80% of MB within 60 minutes of irradiation, whereas ~92% of degradation was achieved in 120 minutes. Complete degradation of MB was observed after 270 minutes of irradiation time. Owing to enhanced photocatalytic degradation efficiency and low-temperature growth method, prepared ZnO nanorod arrays may open up the possibility for the successful utilization of ZnO nanorod arrays as a future photocatalyst for environmental remediation.Keywords: ZnO, nanorods, XRD, photodegradation

  13. Hard Pd Nanorods in the Soft Surfactant Mixture of CTAB and Pluronics: Seedless Synthesis and Their Self-Assembly.

    Song, Hyon-Min; Zink, Jeffrey I

    2018-04-10

    Seedless synthesis of Pd nanorods and their self-assembly into the layered smectic ordering are described. Aqueous Pluronic triblock copolymers (14.3-35.7%) are used as a soft template along with cetyltrimethylammonium bromide for inducing one-dimensional growth of Pd nanorods. Pluronic triblock copolymers are probably the most used polymer surfactants, and they are composed of poly(ethylene oxide) (PEO)-poly(propylene oxide) (PPO)-PEO triblocks. Neither pH adjustment nor AgNO 3 and other additives, such as poly(vinyl pyrrolidone) and ethylene glycol, are required to obtain Pd nanorods. Sonochemical synthesis at 43 °C, followed by thermal annealing for 1 h at 65 °C produces Pd nanorods with the aspect ratio from 3.1 (17.9%, Pluronic L-64) to 6.7 (35.7%, Pluronic P-123). Two-dimensional self-assembly of the nanorods is observed, and both nematic ordering between the mesogens and smectic ordering between the layers is identified. Micellar hydrophobic PPO with hydrated PEO coronas are known to self-assemble into many crystalline orders, including cubic, hexagonal, lamellar, and inverse hexagonal mesophases, which extend into cylindrical micelles with increasing temperature. Relatively small size of Pluronic copolymers with regard to general polymers, but rather large size of their micelles and their tendency to organize into crystalline mesophases are thought to contribute to the anisotropic growth of Pd nanorods.

  14. A model-based approach of scatter dose contributions and efficiency of apron shielding for radiation protection in CT.

    Weber, N; Monnin, P; Elandoy, C; Ding, S

    2015-12-01

    Given the contribution of scattered radiations to patient dose in CT, apron shielding is often used for radiation protection. In this study the efficiency of apron was assessed with a model-based approach of the contributions of the four scatter sources in CT, i.e. external scattered radiations from the tube and table, internal scatter from the patient and backscatter from the shielding. For this purpose, CTDI phantoms filled with thermoluminescent dosimeters were scanned without apron, and then with an apron at 0, 2.5 and 5 cm from the primary field. Scatter from the tube was measured separately in air. The scatter contributions were separated and mathematically modelled. The protective efficiency of the apron was low, only 1.5% in scatter dose reduction on average. The apron at 0 cm from the beam lowered the dose by 7.5% at the phantom bottom but increased the dose by 2% at the top (backscatter) and did not affect the centre. When the apron was placed at 2.5 or 5 cm, the results were intermediate to the one obtained with the shielding at 0 cm and without shielding. The apron effectiveness is finally limited to the small fraction of external scattered radiation. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  15. Convergent Evolution towards High Net Carbon Gain Efficiency Contributes to the Shade Tolerance of Palms (Arecaceae.

    Ren-Yi Ma

    Full Text Available Most palm species occur in the shaded lower strata of tropical rain forests, but how their traits relate to shade adaptation is poorly understood. We hypothesized that palms are adapted to the shade of their native habitats by convergent evolution towards high net carbon gain efficiency (CGEn, which is given by the maximum photosynthetic rate to dark respiration rate ratio. Leaf mass per area, maximum photosynthetic rate, dark respiration and N and P concentrations were measured in 80 palm species grown in a common garden, and combined with data of 30 palm species growing in their native habitats. Compared to other species from the global leaf economics data, dicotyledonous broad-leaved trees in tropical rainforest or other monocots in the global leaf economics data, palms possessed consistently higher CGEn, achieved by lowered dark respiration and fairly high foliar P concentration. Combined phylogenetic analyses of evolutionary signal and trait evolution revealed convergent evolution towards high CGEn in palms. We conclude that high CGEn is an evolutionary strategy that enables palms to better adapt to shady environments than coexisting dicot tree species, and may convey advantages in competing with them in the tropical forest understory. These findings provide important insights for understanding the evolution and ecology of palms, and for understanding plant shade adaptations of lower rainforest strata. Moreover, given the dominant role of palms in tropical forests, these findings are important for modelling carbon and nutrient cycling in tropical forest ecosystems.

  16. THE CONTRIBUTION OF DEONTOLOGICAL RULES TO THE EFFICIENT EXERCISE OF THE RIGHT TO EDUCATION

    Ștefania Cristina Mirică

    2017-12-01

    Full Text Available In this article, we intend to analyse the provisions of the code of ethics in pre- university education in order to identify the effective ways in which this normative act will contribute to the improvement of the Romanian education and how the children will continue to benefit of the absolutely necessary right to an adequate education, meant to prepare them for a decent life as adults, in Romania and anywhere else would choose to live. The Romanian Constitution establishes, in Article 32, the child's right to an education, the first provision referring to mandatory education. Thus, to a certain extent and level, in any civilized state, children must receive free education. Romanian pre-university education is currently facing several problems: the drop in birth rate, which results in a small number of children in schools, drop-out at a young age, a lower number of teachers, etc. From our point of view, a major problem of Romanian educational system refers to the low respect of children towards school, teaching and teachers, the main causes of this situation, probably consisting of material shortages and the departure of parents abroad in order to be able to support the family and leaving children without proper moral and emotional support. The new draft of the code of ethics for pre-university teachers intends to enrich the Romanian legislation with another code of ethics and also, it tries to solve, at least in part, some of the Romanian' educational system problems.

  17. Oxidation dynamics of aluminum nanorods

    Li, Ying [Argonne Leadership Computing Facility, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Chemical Engineering and Materials Science, Department of Computer Science, University of Southern California, Los Angeles, California 90089-0242 (United States)

    2015-02-23

    Aluminum nanorods (Al-NRs) are promising fuels for pyrotechnics due to the high contact areas with oxidizers, but their oxidation mechanisms are largely unknown. Here, reactive molecular dynamics simulations are performed to study thermally initiated burning of oxide-coated Al-NRs with different diameters (D = 26, 36, and 46 nm) in oxygen environment. We found that thinner Al-NRs burn faster due to the larger surface-to-volume ratio. The reaction initiates with the dissolution of the alumina shell into the molten Al core to generate heat. This is followed by the incorporation of environmental oxygen atoms into the resulting Al-rich shell, thereby accelerating the heat release. These results reveal an unexpectedly active role of the alumina shell as a “nanoreactor” for oxidation.

  18. Simply synthesized TiO2 nanorods as an effective scattering layer for quantum dot sensitized solar cells

    Samadpour, Mahmoud; Zad, Azam Iraji; Molaei, Mehdi

    2014-01-01

    TiO 2 nanorod layers are synthesized by simple chemical oxidation of Ti substrates. Diffuse reflectance spectroscopy measurements show effective light scattering properties originating from nanorods with length scales on the order of one micron. The films are sensitized with CdSe quantum dots (QDs) by successive ionic layer adsorption and reaction (SILAR) and integrated as a photoanode in quantum dot sensitized solar cells (QDSCs). Incorporating nanorods in photoanode structures provided 4- to 8-fold enhancement in light scattering, which leads to a high power conversion efficiency, 3.03% (V oc = 497 mV, J sc = 11.32 mA/cm 2 , FF = 0.54), in optimized structures. High efficiency can be obtained just by tuning the photoanode structure without further treatments, which will make this system a promising nanostructure for efficient quantum dot sensitized solar cells. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  19. CONTRIBUTION OF QUADRATIC RESIDUE DIFFUSERS TO EFFICIENCY OF TILTED PROFILE PARALLEL HIGHWAY NOISE BARRIERS

    M. R. Monazzam ، P. Nassiri

    2009-10-01

    Full Text Available This paper presents the results of an investigation on the acoustic performance of tilted profile parallel barriers with quadratic residue diffuser (QRD tops and faces. A 2D boundary element method (BEM is used to predict the barrier insertion loss. The results of rigid and with absorptive coverage are also calculated for comparisons. Using QRD on the top surface and faces of all tilted profile parallel barrier models introduced here is found to improve the efficiency of barriers compared with rigid equivalent parallel barrier at the examined receiver positions. Applying a QRD with frequency design of 400 Hz on 5 degrees tilted parallel barrier improves the overall performance of its equivalent rigid barrier by 1.8 dB(A. Increase in the treated surfaces with reactive elements shifts the effective performance toward lower frequencies. It is found that by tilting the barriers from 0 to 10 degrees in parallel set up, the degradation effects in parallel barriers is reduced but the absorption effect of fibrous materials and also diffusivity of the quadratic residue diffuser is reduced significantly. In this case all the designed barriers have better performance with 10 degrees tilting in parallel set up. The most economic traffic noise parallel barrier which produces significantly high performance, is achieved by covering the top surface of the barrier closed to the receiver by just a QRD with frequency design of 400 Hz and tilting angle of 10 degrees. The average A-weighted insertion loss in this barrier is predicted to be 16.3 dB (A.

  20. Contribution of diffuser surfaces to efficiency of tilted T shape parallel highway noise barriers

    N. Javid Rouzi

    2009-04-01

    Full Text Available Background and aimsThe paper presents the results of an investigation on the acoustic  performance of tilted profile parallel barriers with quadratic residue diffuser tops and faces.MethodsA2D boundary element method (BEM is used to predict the barrier insertion loss. The results of rigid and with absorptive coverage are also calculated for comparisons. Using QRD on the top surface and faces of all tilted profile parallel barrier models introduced here is found to  improve the efficiency of barriers compared with rigid equivalent parallel barrier at the examined  receiver positions.Results Applying a QRD with frequency design of 400 Hz on 5 degrees tilted parallel barrier  improves the overall performance of its equivalent rigid barrier by 1.8 dB(A. Increase the treated surfaces with reactive elements shifts the effective performance toward lower frequencies. It is  found that by tilting the barriers from 0 to 10 degrees in parallel set up, the degradation effects in  parallel barriers is reduced but the absorption effect of fibrous materials and also diffusivity of thequadratic residue diffuser is reduced significantly. In this case all the designed barriers have better  performance with 10 degrees tilting in parallel set up.ConclusionThe most economic traffic noise parallel barrier, which produces significantly  high performance, is achieved by covering the top surface of the barrier closed to the receiver by  just a QRD with frequency design of 400 Hz and tilting angle of 10 degrees. The average Aweighted  insertion loss in this barrier is predicted to be 16.3 dB (A.

  1. Quantifying the Contribution of Urban-Industrial Efficiency and Symbiosis to Deep Decarbonization: Impact of 637 Chinese Cities

    Ramaswami, A.; Tong, K.; Fang, A.; Lal, R.; Nagpure, A.; Li, Y.; Yu, H.; Jiang, D.; Russell, A. G.; Shi, L.; Chertow, M.; Wang, Y.; Wang, S.

    2016-12-01

    Urban activities in China contribute significantly to global greenhouse gas (GHG) emissions and to local air pollution-related health risks. Co-location analysis can help inform the potential for energy- and material-exchanges across homes, businesses, infrastructure and industries co-located in cities. Such co-location dependent urban-industrial symbiosis strategies offer a new pathway toward urban energy efficiency and health that have not previously been quantified. Key examples includes the use of waste industrial heat in other co-located industries, and in residential-commercial district heating-cooling systems of cities. To quantify the impact of these strategies: (1) We develop a new data-set of 637 Chinese cities to assess the potential for efficiency and symbiosis across co-located homes, businesses, industries and the energy and construction sectors in the different cities. (2) A multi-scalar urban systems model quantifies trans-boundary CO2 impacts as well as local health benefits of these uniquely urban, co-location-dependent strategies. (3) CO2 impacts are aggregated across the 637 Chinese cities (home to 701 million people) to quantify national CO2 mitigation potential. (4) The local health benefits are modeled specific to each city and mapped geospatially to identify areas where co-benefits between GHG mitigation and health are maximized. Results: A first order conservative analysis of co-location dependent urban symbiosis indicates potential for reducing 6% of China's national total CO2 emissions in a relatively short time period, yielding a new pathway not previously considered in China's energy futures models. The magnitude of these reductions (6%) was similar in magnitude to sector specific industrial, power sector and buildings efficiency strategeies that together contributed 9% CO2 reduction aggregated across the nation. CO2 reductions mapped to the 637 cities ranged from 40,000 premature deaths (avoided) across all cities. These results

  2. Optimization of Kaplan turbines. A contribution to economic efficiency; Optimierung von Kaplan-Turbinen. Ein Beitrag zur Betriebswirtschaftlichkeit

    Sevcik, Petr

    2009-07-01

    The Kaplan turbine has the best theoretical efficiency chart in the total range of operation. In order to achieve these good properties, the turbine has to be adjusted optimally. In general, these settings are performed by the manufacturer of turbines during commissioning. In practice one often meets Kaplan turbines where the scenery does not correspond to the optimal control line. The author of the contribution under consideration reports on possible causes for these errors and also methods of how this scenery can be optimized cost-effectively and how to minimize power losses.

  3. Contributing to Net Zero Building: High Energy Efficient EIFS Wall Systems

    Carbary, Lawrence D. [Dow Corning Corporation; Perkins, Laura L. [Dow Corning Corporation; Serino, Roland [Dryvit Systems, Inc; Preston, Bill [Dryvit Systems, Inc; Kosny, Jan [Fraunhofer USA, Inc. CSE

    2014-01-29

    The team led by Dow Corning collaborated to increase the thermal performance of exterior insulation and finishing systems (EIFS) to reach R-40 performance meeting the needs for high efficiency insulated walls. Additionally, the project helped remove barriers to using EIFS on retrofit commercial buildings desiring high insulated walls. The three wall systems developed within the scope of this project provide the thermal performance of R-24 to R-40 by incorporating vacuum insulation panels (VIPs) into an expanded polystyrene (EPS) encapsulated vacuum insulated sandwich element (VISE). The VISE was incorporated into an EIFS as pre-engineered insulation boards. The VISE is installed using typical EIFS details and network of trained installers. These three wall systems were tested and engineered to be fully code compliant as an EIFS and meet all of the International Building Code structural, durability and fire test requirements for a code compliant exterior wall cladding system. This system is being commercialized under the trade name Dryvit® Outsulation® HE system. Full details, specifications, and application guidelines have been developed for the system. The system has been modeled both thermally and hygrothermally to predict condensation potential. Based on weather models for Baltimore, MD; Boston, MA; Miami, FL; Minneapolis, MN; Phoenix, AZ; and Seattle, WA; condensation and water build up in the wall system is not a concern. Finally, the team conducted a field trial of the system on a building at the former Brunswick Naval Air Station which is being redeveloped by the Midcoast Regional Redevelopment Authority (Brunswick, Maine). The field trial provided a retrofit R-30 wall onto a wood frame construction, slab on grade, 1800 ft2 building, that was monitored over the course of a year. Simultaneous with the façade retrofit, the building’s windows were upgraded at no charge to this program. The retrofit building used 49% less natural gas during the winter of

  4. New trend for synthesizing of magnetic nanorods with titanomaghemite structure

    Saber, Osama, E-mail: osmohamed@kfu.edu.sa [Faculty of Science, King Faisal University, P.O. Box 400, Al-Hassa 31982 (Saudi Arabia); Egyptian Petroleum Research Institute, Nasr City, P.O. Box 11727, Cairo (Egypt)

    2016-07-15

    This research aims at developing magnetic and optical materials through fabrication of uniform nanorods by facile and novel technique. In this trend, titanium and iron were successfully combined together forming nanorods without template or high temperature by urea hydrolysis. TEM images showed uniform and homogeneous nanorods with dimensions; 10 nm in width and 50 nm in length. In the same time, fine nanoparticles were observed around the nanorods. With further treatment for the nanorods at high temperature and pressure, FESEM images revealed that the dimensions of the rods slightly increased to be 70 nm in length and 12 nm in width with a complete disappearance of the nanoparticles. Using X-ray diffraction, thermal analyses and infrared spectra in addition to the results of the electron microscopy, the oriented attachment mechanism was suggested for the formation of titanium iron oxides nanorods. The magnetic measurements revealed that the prepared nanorods possess ferromagnetic behavior and exhibit high saturation magnetization. Also, the optical properties showed that the nanorods have high absorption in the visible region and possess low band gap energy. Finally, we concluded that it is probably the first time to prepare nanorods by urea hydrolysis. The advanced optical and magnetic properties give the prepared nanorods relevance to use as building blocks in functional nanoscale devices. - Graphical abstract: The present study has a dual aim for developing new and facile method for fabrication of nanorods containing titanomaghemite structure and improving their optical and magnetic properties - Highlights: • Synthesis of titanium iron oxides nanorods with titanomaghemite structure. • Using urea hydrolysis for preparation of nanorods. • Studying of the effect of pressure and temperature on the nanorods. • Enhancement of the magnetic properties of the nanorods in comparison with the nanoparticles. • Improvement of the optical properties of the nanorods

  5. Formation and electrical transport properties of pentacene nanorod crystal

    Akai-Kasaya, M; Ohmori, C; Kawanishi, T; Nashiki, M; Saito, A; Kuwahara, Y; Aono, M

    2010-01-01

    The monophasic formation of an uncharted pentacene crystal, the pentacene nanorod, has been investigated. The restricted formation of the pentacene nanorod on a bare mica surface reveals a peculiar surface catalytic crystal growth mode of the pentacene. We demonstrated the charge transport measurements through a single pentacene nanorod and analyzed the data using a periodic hopping conduction model. The results revealed that the pentacene nanorod has a periodic conductive node within their one-dimensional crystal.

  6. Formation and electrical transport properties of pentacene nanorod crystal.

    Akai-Kasaya, M; Ohmori, C; Kawanishi, T; Nashiki, M; Saito, A; Aono, M; Kuwahara, Y

    2010-09-10

    The monophasic formation of an uncharted pentacene crystal, the pentacene nanorod, has been investigated. The restricted formation of the pentacene nanorod on a bare mica surface reveals a peculiar surface catalytic crystal growth mode of the pentacene. We demonstrated the charge transport measurements through a single pentacene nanorod and analyzed the data using a periodic hopping conduction model. The results revealed that the pentacene nanorod has a periodic conductive node within their one-dimensional crystal.

  7. Hexagonal pencil-like CdS nanorods: Facile synthesis and enhanced visible light photocatalytic performance

    An, Liang; Wang, Guanghui; Zhao, Lei; Zhou, Yong; Gao, Fang; Cheng, Yang

    2015-07-01

    In the present study, hexagonal pencil-like CdS nanorods have been successfully synthesized through a typical facile and economical one-step hydrothermal method without using any surfactant or template. The product was characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and energy dispersive analysis of X-ray (EDX). The results revealed that the prepared CdS photocatalyst consisted of a large quantity of straight and smooth solid hexagonal nanorods and a few nanoparticles. The photocatalytic activities of CdS nanorods and commercial CdS powders were investigated by the photodegradation of Orange II (OII) in aqueous solution under visible light, and the CdS nanorods presented the highest photocatalytic activity. Its photocatalytic efficiency enhancement was attributed to the improved transmission of photogenerated electron-hole pairs in the CdS nanostructures. The present findings may provide a facile approach to synthesize high efficient CdS photocatalysts.

  8. Hydrothermal route to VO2 (B) nanorods: controlled synthesis and characterization

    Song, Shaokun; Huang, Qiwei; Zhu, Wanting

    2017-10-01

    One-dimensional vanadium dioxides have attracted intensive attention owing to their distinctive structure and novel applications in catalysis, high energy lithium-ion batteries, chemical sensors/actuators and electrochemical devices etc. In this paper, large-scale VO2 (B) nanorods have been successfully synthesized via a versatile and environment friendly hydrothermal strategy using V2O5 as vanadium source and carbohydrates/alcohols as reductant. The obtained samples are characterized by XRD, FT-IR, TEM, and XPS techniques to investigate the effects of chemical parameters such as reductants, temperature, and time of synthesis on the structure and morphology of products. Results show that pure B phase VO2 with homogeneous nanorod-like morphology can be prepared easily at 180 °C for 3 days with glycerol as reluctant. Typically, the nanorod-like products are 0.5-1 μm long and 50 nm width. Furthermore, it is also confirmed that the products are consisted of VO2, corresponding to the B phase. More importantly, this novel approach is efficient, free of any harmful solvents and surfactants. Therefore, this efficient, green, and cost-saving route will have great potential in the large-scale fabrication of 1D VO2 (B) nanorods from the economic and environmental point of view.

  9. Carrier-free, functionalized pure drug nanorods as a novel cancer-targeted drug delivery platform

    Li Yanan; An Feifei; Zhang Xiaohong; Yang Yinlong; Liu Zhuang; Zhang Xiujuan

    2013-01-01

    A one-dimensional drug delivery system (1D DDS) is highly attractive since it has distinct advantages such as enhanced drug efficiency and better pharmacokinetics. However, drugs in 1D DDSs are all encapsulated in inert carriers, and problems such as low drug loading content and possible undesirable side effects caused by the carriers remain a serious challenge. In this paper, a novel, carrier-free, pure drug nanorod-based, tumor-targeted 1D DDS has been developed. Drugs are first prepared as nanorods and then surface functionalized to achieve excellent water dispersity and stability. The resulting drug nanorods show enhanced internalization rates mainly through energy-dependent endocytosis, with the shape-mediated nanorod (NR) diffusion process as a secondary pathway. The multiple endocytotic mechanisms lead to significantly improved drug efficiency of functionalized NRs with nearly ten times higher cytotoxicity than those of free molecules and unfunctionalized NRs. A targeted drug delivery system can be readily achieved through surface functionalization with targeting group linked amphipathic surfactant, which exhibits significantly enhanced drug efficacy and discriminates between cell lines with high selectivity. These results clearly show that this tumor-targeting DDS demonstrates high potential toward specific cancer cell lines. (paper)

  10. Plasmonic thin film InP/graphene-based Schottky-junction solar cell using nanorods

    Abedin Nematpour

    2018-03-01

    Full Text Available Herein, the design and simulation of graphene/InP thin film solar cells with a novel periodic array of nanorods and plasmonic back-reflectors of the nano-semi sphere was proposed. In this structure, a single-layer of the graphene sheet was placed on the vertical nanorods of InP to form a Schottky junction. The electromagnetic field was determined using solving three-dimensional Maxwell's equations discretized by the finite difference method (FDM. The enhancement of light trapping in the absorbing layer was illustrated, thereby increasing the short circuit current to a maximum value of 31.57 mA/cm2 with nanorods having a radius of 400 nm, height of 1250 nm, and nano-semi sphere radius of 50 nm, under a solar irradiation of AM1.5G. The maximum ultimate efficiency was determined to be 45.8% for an angle of incidence of 60°. This structure has shown a very good light trapping ability when graphene and ITO layers were used at the top and as a back-reflector in the proposed photonic crystal structure of the InP nanorods. Thence, this structure improves the short-circuit current density and the ultimate efficiency of 12% and 2.7%, respectively, in comparison with the InP-nanowire solar cells.

  11. Alq3 nanorods: promising building blocks for optical devices.

    Chen, Wei; Peng, Qing; Li, Yadong

    2008-07-17

    Monodisperse Alq3 nanorods with hexagonal-prism-like morphology are produced via a facile, emulsion based synthesis route. The photoluminescence of individual nanorods differs from the bulk material. These nanorods are promising building blocks for novel optical devices. Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Tragacanth gum biopolymer as reducing and stabilizing agent in biosonosynthesis of urchin-like ZnO nanorod arrays: A low cytotoxic photocatalyst with antibacterial and antifungal properties.

    Ghayempour, Soraya; Montazer, Majid; Mahmoudi Rad, Mahnaz

    2016-01-20

    Tragacanth, a natural gum, has been used for centuries as emulsifier, thickener, stabilizer and binder in various fields such as food, medical and cosmetic industries. In this study, Tragacanth gum was used as a clean and natural reducing and stabilizing agent for preparation of urchin-like ZnO nanorod arrays at low-temperature using ultrasonic irradiation. The morphology and structure of urchin-like ZnO nanorod arrays was investigated by XRD, FESEM images, EDX, UV-vis and FT-IR spectroscopy. The hexagonal zinc oxide nanorods were synthesized with the average diameter of 55-80 nm and length of 240 nm. The peak appeared in 447 cm(-1) in FTIR spectra and the peak around 362.3 nm in UV-vis spectra of ZnO nanorods confirmed the successful synthesis of ZnO nanorods. The urchin-like ZnO nanorod arrays indicated a good photocatalytic activity through degradation of methylene blue with 92.2% efficiency and rate constant of 0.0027 min(-1) at 120 min. Finally, the synthesized urchin-like ZnO nanorod arrays indicated 100% antibacterial activity against S. aureus and E. coli and 93% antifungal activity against C. albicans with a low cytotoxicity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Growth process for gallium nitride porous nanorods

    Wildeson, Isaac Harshman; Sands, Timothy David

    2015-03-24

    A GaN nanorod and formation method. Formation includes providing a substrate having a GaN film, depositing SiN.sub.x on the GaN film, etching a growth opening through the SiN.sub.x and into the GaN film, growing a GaN nanorod through the growth opening, the nanorod having a nanopore running substantially through its centerline. Focused ion beam etching can be used. The growing can be done using organometallic vapor phase epitaxy. The nanopore diameter can be controlled using the growth opening diameter or the growing step duration. The GaN nanorods can be removed from the substrate. The SiN.sub.x layer can be removed after the growing step. A SiO.sub.x template can be formed on the GaN film and the GaN can be grown to cover the SiO.sub.x template before depositing SiN.sub.x on the GaN film. The SiO.sub.x template can be removed after growing the nanorods.

  14. Modelling and characterization of photothermal effects assisted with gold nanorods in ex vivo samples and in a murine model

    Lamela Rivera, Horacio; Rodríguez Jara, Félix; Cunningham, Vincent

    2011-03-01

    We discuss in this article the implementation of a laser-tissue interaction and bioheat-transfer 2-D finite-element model for Photothermal Therapy assisted with Gold Nanorods. We have selected Gold Nanorods as absorbing nanostructures in order to improve the efficiency of using compact diode lasers because of their high opto-thermal conversion efficiency at 808 and 850 nm. The goal is to model the distribution of the optical energy among the tissue including the skin absorption effects and the tissue thermal response, with and without the presence of Gold Nanorods. The heat generation due to the optical energy absorption and the thermal propagation will be computationally modeled and optimized. The model has been evaluated and compared with experimental ex-vivo data in fresh chicken muscle samples and in-vivo BALB/c mice animal model.

  15. Sensing based on the motion of enzyme-modified nanorods

    Bunea, Ada-Ioana; Pavel, Ileana-Alexandra; David, Sorin

    2015-01-01

    of nanorods modified with the appropriate enzyme. Nanorods, with a Pt and a polypyrrole (PPy) segment, were fabricated. The PPy segment of such nanorods was then modified with glucose oxidase (GOx), glutamate oxidase (GluOx), or xanthine oxidase (XOD). Calibration curves, linking the diffusion coefficient...... of the oxidase-modified nanorods to the concentration of the oxidase substrate, were subsequently built. The oxidase-modified nanorods and their calibration curves were finally used to determine substrate concentrations both in simple aqueous solutions and in complex samples such as horse serum and cell culture...

  16. Electrical characterization of ZnO nanorods

    Schlenker, E.; Bakin, A.; Postels, B.; Mofor, A.C.; Wehmann, H.H.; Waag, A. [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Weimann, T.; Hinze, P. [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany)

    2007-05-15

    Zinc oxide (ZnO) nanorods were grown by a wet chemical approach and by vapor phase transport. To explore the electrical properties of individual nanostructures current-voltage (I-V) characteristics were obtained by using an atomic force microscope (AFM) with a conductive tip or by detaching the nanorods from the growth substrate, transferring them to an isolating substrate and contacting them with evaporated Ti/Au electrodes patterned by electron-beam lithography. The AFM-approach only yields a Schottky diode behavior, while the Ti/Au forms ohmic contacts to the ZnO. For the latter method the obtained I-V curves reveal a resistivity of the nanorods in the order of 10{sup -5} {omega} cm which is unusually low for undoped ZnO. We therefore assume the existence of a highly conductive surface channel. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Elements in the canine distemper virus M 3' UTR contribute to control of replication efficiency and virulence.

    Danielle E Anderson

    Full Text Available Canine distemper virus (CDV is a negative-sense, single-stranded RNA virus within the genus Morbillivirus and the family Paramyxoviridae. The Morbillivirus genome is composed of six transcriptional units that are separated by untranslated regions (UTRs, which are relatively uniform in length, with the exception of the UTR between the matrix (M and fusion (F genes. This UTR is at least three times longer and in the case of CDV also highly variable. Exchange of the M-F region between different CDV strains did not affect virulence or disease phenotype, demonstrating that this region is functionally interchangeable. Viruses carrying the deletions in the M 3' UTR replicated more efficiently, which correlated with a reduction of virulence, suggesting that overall length as well as specific sequence motifs distributed throughout the region contribute to virulence.

  18. Field electron emission improvement of ZnO nanorod arrays after Ar plasma treatment

    Li Chun; Fang Guojia; Yuan Longyan; Liu Nishuang; Li Jun; Li Dejie; Zhao Xingzhong

    2007-01-01

    Vertically well-aligned single crystal ZnO nanorod arrays were synthesized and enhanced field electron emission was achieved after radio-frequency (rf) Ar plasma treatment. With Ar plasma treatment for 30 min, flat tops of the as-grown ZnO nanorods have been etched into sharp tips without damaging ZnO nanorod geometrical morphologies and crystallinity. After the Ar ion bombardment, the emission current density increases from 2 to 20 μA cm -2 at 9.0 V μm -1 with a decrease in turn-on voltage from 7.1 to 4.8 V μm -1 at a current density of 1 μA cm -2 , which demonstrates that the field emission of the as-grown ZnO nanorods has been efficiently enhanced. The scanning electron microscopy (SEM) results, in conjunction with the results of transmission electron microscopy (TEM), Raman spectroscopy and photoluminescence observation, are used to investigate the mechanisms of the field emission enhancement. It is believed that the enhancements can be mainly attributed to the sharpening of rod tops, and the decrease of electrostatic screening effect

  19. Doping effects of Co2+ ions on ZnO nanorods and their photocatalytic properties

    Qiu Xiaoqing; Li Guangshe; Sun Xuefei; Li Liping; Fu Xianzhi

    2008-01-01

    A series of Zn 1-x Co x O nanorods with dopant content ranging from x = 0.00 to 0.10 was prepared by a wet chemical method. All Zn 1-x Co x O samples were investigated by x-ray diffraction, transmission electron microscopy, energy-dispersion x-ray line mapping analysis, and UV-visible absorption spectroscopy. It was found that Co 2+ ions were homogeneously substituted for Zn 2+ ions in ZnO nanorods. Rhodamine B degradation was used as a probe reaction to evaluate the effect of Co 2+ doping on ZnO nanorods and photocatalytic performance under UV light and visible light irradiation. Co 2+ ions acted as the trapping or recombination centers for electrons and holes, leading to a reduction in photodegradation efficiency under UV light illumination. Alternatively, Co 2+ ions enhanced the optical absorption and produced the photoinduced carriers under visible illumination in terms of two charge transfer transitions involving Co 2+ ions. Consequently, Co 2+ ions substituted in the lattice of ZnO nanorods significantly improved the visible light photocatalytic activity

  20. Facile synthesis of ZnO/CuInS{sub 2} nanorod arrays for photocatalytic pollutants degradation

    Yang, Yawei [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, School of Electronic & Information Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Que, Wenxiu, E-mail: wxque@mail.xjtu.edu.cn [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, School of Electronic & Information Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Zhang, Xinyu [Frontier Institute of Science and Technology Jointly with College of Science, State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Xing, Yonglei; Yin, Xingtian [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, School of Electronic & Information Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Du, Yaping, E-mail: ypdu2013@mail.xjtu.edu.cn [Frontier Institute of Science and Technology Jointly with College of Science, State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China)

    2016-11-05

    Highlights: • Vertically-aligned ZnO nanorod arrays were synthesized by the hydrothermal process. • Monodisperse CuInS{sub 2} QDs were synthesized by the one-pot colloidal chemistry method. • ZnO/CuInS{sub 2} nanorod arrays films were fabricated by the EPD process. • The homogeneous CuInS{sub 2} loading was optimized by EPD duration. • The photoelectrochemical and photocatalytic activities of the ZnO/CuInS{sub 2} nanorod arrays films were discussed. - Abstract: Vertically-aligned ZnO nanorod arrays on a fluorine-doped tin oxide glass substrate were homogeneously coated with visible light active CuInS{sub 2} quantum dots by using a controllable electrophoretic deposition strategy. Compared with the pure ZnO nanorod arrays, the formation of high-quality ZnO/CuInS{sub 2} heterojunction with well-matched band energy alignment expanded the light absorption from ultraviolet to visible region and facilitated efficient charge separation and transportation, thus yielding remarkable enhanced photoelectrochemical performance and photocatalytic activities for methyl orange and 4-chlorophenol degradation. The ZnO/CuInS{sub 2} film with the deposition duration of 80 min showed the highest degradation rate and photocurrent density (0.95 mA/cm{sup 2}), which was almost 6.33 times higher than that of the pure ZnO nanorod arrays film. The CuInS{sub 2} QDs sensitized ZnO nanorod arrays film was proved to be a superior structure for photoelectrochemical and photocatalytic applications due to the optimized CuInS{sub 2} loading and well-maintained one-dimensional nanostructure.

  1. Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks

    Canadella, J.G.; Raupacha, M.R.; Le Quere, C.; Buitenhuis, E.T.; Gillett, N.P.; Field, C.B.; Ciais, P.; Conway, T.J.; Houghton, R.A.; Marland, G.

    2007-01-01

    The growth rate of atmospheric carbon dioxide (CO2), the largest human contributor to human-induced climate change, is increasing rapidly. Three processes contribute to this rapid increase. Two of these processes concern emissions. Recent growth of the world economy combined with an increase in its carbon intensity have led to rapid growth in fossil fuel CO2 emissions since 2000: comparing the 1990s with 2000-2006, the emissions growth rate increased from 1.3% to 3.3%/y. The third process is indicated by increasing evidence (P 0.89) for a long-term (50-year) increase in the airborne fraction (AF) of CO2 emissions, implying a decline in the efficiency of CO2 sinks on land and oceans in absorbing anthropogenic emissions. Since 2000, the contributions of these three factors to the increase in the atmospheric CO2 growth rate have been ∼65 ± 16% from increasing global economic activity, 17 ± 6% from the increasing carbon intensity of the global economy, and 18 ± 15% from the increase in AF. An increasing AF is consistent with results of climate-carbon cycle models, but the magnitude of the observed signal appears larger than that estimated by models. All of these changes characterize a carbon cycle that is generating stronger-than-expected and sooner-than-expected climate forcing. airborne fraction anthropogenic carbon emissions carbon-climate feedback terrestrial and ocean carbon emissions vulnerabilities of the carbon cycle

  2. Optical Asymmetry and Nonlinear Light Scattering from Colloidal Gold Nanorods.

    Lien, Miao-Bin; Kim, Ji-Young; Han, Myung-Geun; Chang, You-Chia; Chang, Yu-Chung; Ferguson, Heather J; Zhu, Yimei; Herzing, Andrew A; Schotland, John C; Kotov, Nicholas A; Norris, Theodore B

    2017-06-27

    A systematic study is presented of the intensity-dependent nonlinear light scattering spectra of gold nanorods under resonant excitation of the longitudinal surface plasmon resonance (SPR). The spectra exhibit features due to coherent second and third harmonic generation as well as a broadband feature that has been previously attributed to multiphoton photoluminescence arising primarily from interband optical transitions in the gold. A detailed study of the spectral dependence of the scaling of the scattered light with excitation intensity shows unexpected scaling behavior of the coherent signals, which is quantitatively accounted for by optically induced damping of the SPR mode through a Fermi liquid model of the electronic scattering. The broadband feature is shown to arise not from luminescence, but from scattering of the second-order longitudinal SPR mode with the electron gas, where efficient excitation of the second order mode arises from an optical asymmetry of the nanorod. The electronic-temperature-dependent plasmon damping and the Fermi-Dirac distribution together determine the intensity dependence of the broadband emission, and the structure-dependent absorption spectrum determines the spectral shape through the fluctuation-dissipation theorem. Hence a complete self-consistent picture of both coherent and incoherent light scattering is obtained with a single set of physical parameters.

  3. Outcomes of Zika virus infection during pregnancy: contributions to the debate on the efficiency of cohort studies.

    Duarte, Elisabeth Carmen; Garcia, Leila Posenato; de Araújo, Wildo Navegantes; Velez, Maria P

    2017-12-02

    Zika infection during pregnancy (ZIKVP) is known to be associated with adverse outcomes. Studies on this matter involve both rare outcomes and rare exposures and methodological choices are not straightforward. Cohort studies will surely offer more robust evidences, but their efficiency must be enhanced. We aim to contribute to the debate on sample selection strategies in cohort studies to assess outcomes associated with ZKVP. A study can be statistically more efficient than another if its estimates are more accurate (precise and valid), even if the studies involve the same number of subjects. Sample size and specific design strategies can enhance or impair the statistical efficiency of a study, depending on how the subjects are distributed in subgroups pertinent to the analysis. In most ZIKVP cohort studies to date there is an a priori identification of the source population (pregnant women, regardless of their exposure status) which is then sampled or included in its entirety (census). Subsequently, the group of pregnant women is classified according to exposure (presence or absence of ZIKVP), respecting the exposed:unexposed ratio in the source population. We propose that the sample selection be done from the a priori identification of groups of pregnant women exposed and unexposed to ZIKVP. This method will allow for an oversampling (even 100%) of the pregnant women with ZKVP and a optimized sampling from the general population of pregnant women unexposed to ZIKVP, saving resources in the unexposed group and improving the expected number of incident cases (outcomes) overall. We hope that this proposal will broaden the methodological debate on the improvement of statistical power and protocol harmonization of cohort studies that aim to evaluate the association between Zika infection during pregnancy and outcomes for the offspring, as well as those with similar objectives.

  4. Interfacial engineering of CuO nanorod/ZnO nanowire hybrid nanostructure photoanode in dye-sensitized solar cell

    Kilic, Bayram; Turkdogan, Sunay; Astam, Aykut; Baran, Sümeyra Seniha; Asgin, Mansur; Gur, Emre; Kocak, Yusuf

    2018-01-01

    Developing efficient and cost-effective photoanode plays a vital role determining the photocurrent and photovoltage in dye-sensitized solar cells (DSSCs). Here, we demonstrate DSSCs that achieve relatively high power conversion efficiencies (PCEs) by using one-dimensional (1D) zinc oxide (ZnO) nanowires and copper (II) oxide (CuO) nanorods hybrid nanostructures. CuO nanorod-based thin films were prepared by hydrothermal method and used as a blocking layer on top of the ZnO nanowires' layer. The use of 1D ZnO nanowire/CuO nanorod hybrid nanostructures led to an exceptionally high photovoltaic performance of DSSCs with a remarkably high open-circuit voltage (0.764 V), short current density (14.76 mA/cm2 under AM1.5G conditions), and relatively high solar to power conversion efficiency (6.18%) . The enhancement of the solar to power conversion efficiency can be explained in terms of the lag effect of the interfacial recombination dynamics of CuO nanorod-blocking layer on ZnO nanowires. This work shows more economically feasible method to bring down the cost of the nano-hybrid cells and promises for the growth of other important materials to further enhance the solar to power conversion efficiency.

  5. A novel fabrication of MEH-PPV/Al:ZnO nanorod arrays based ordered bulk heterojunction hybrid solar cells

    Malek, M.F., E-mail: firz_solarzelle@yahoo.com [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Sahdan, M.Z.; Mamat, M.H.; Musa, M.Z. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Khusaimi, Z.; Husairi, S.S. [NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA -UiTM, 40450 Shah Alam, Selangor (Malaysia); Md Sin, N.D. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Rusop, M. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA - UiTM, 40450 Shah Alam, Selangor (Malaysia)

    2013-06-15

    Vertically aligned Al:ZnO nanorod arrays has been used as window layer in the fabrication of ordered bulk heterojuction hybrid solar cells. The utilization of the nanorod arrays will enhance the electron transport in vertical direction and also for light harvesting applications for high performance devices. The performance of this hybrid polymer/metal oxide photovoltaic devices based on MEH-PPV [poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene)] and oriented Al:ZnO nanorod arrays is studied. The Al:ZnO nanorod arrays with a diameter of about 70–80 nm and thickness of approximately 500 nm were successfully grown on Al:ZnO-coated ITO substrate by sonicated sol–gel immersion technique. The photovoltaic performance of a short-circuit current density of 5.320 mA/cm{sup 2}, an open-circuit voltage of 195 mV and a fill factor of 27.71%, with a power conversion efficiency of about 0.287% under AM 1.5 illumination (100 mW/cm{sup 2}). To the best of our knowledge, preparation of aligned Al:ZnO nanorod arrays for this type of solar cell fabrication has not been reported by any research group.

  6. Vertically aligned ZnO nanorods via self-assembled spray pyrolyzed nanoparticles for dye-sensitized solar cells

    Dwivedi, Charu; Dutta, V

    2012-01-01

    Well-aligned zinc oxide (ZnO) nanorods are fabricated on indium-tin-oxide (ITO) coated glass substrates via self-assembly of ZnO nanoparticles created using continuous spray pyrolysis (CoSP) technique. The method involves pre-treatment by dip-coating the substrate with a solution comprising of zinc salt for creating a seed layer, and then spray-pyrolyzed ZnO nanoparticles self-assemble on the pre-treated substrate. The effect of the substrate pre-treatment and the deposition time (t dep ) of nanoparticles is investigated. The results show that the substrate pre-treatment influences the growth of ZnO nanorods which are absent without the pre-treatment. Nanoparticle collection and nanorod growth on different substrates are done simultaneously. The thin films of as-grown nanorods are used as photoelectrode materials to fabricate dye-sensitized solar cells (DSSCs) and the effect of nanorods grown for different times has been studied. The best performance with this cell structure is found for the layer with t dep =15 min, which showed a conversion efficiency of 1.77% for the cell area of 0.25 cm 2

  7. Fabrication of Vertically Aligned Carbon Nanotube or Zinc Oxide Nanorod Arrays for Optical Diffraction Gratings.

    Kim, Jeong; Kim, Sun Il; Cho, Seong-Ho; Hwang, Sungwoo; Lee, Young Hee; Hur, Jaehyun

    2015-11-01

    We report on new fabrication methods for a transparent, hierarchical, and patterned electrode comprised of either carbon nanotubes or zinc oxide nanorods. Vertically aligned carbon nanotubes or zinc oxide nanorod arrays were fabricated by either chemical vapor deposition or hydrothermal growth, in combination with photolithography. A transparent conductive graphene layer or zinc oxide seed layer was employed as the transparent electrode. On the patterned surface defined using photoresist, the vertically grown carbon nanotubes or zinc oxides could produce a concentrated electric field under applied DC voltage. This periodic electric field was used to align liquid crystal molecules in localized areas within the optical cell, effectively modulating the refractive index. Depending on the material and morphology of these patterned electrodes, the diffraction efficiency presented different behavior. From this study, we established the relationship between the hierarchical structure of the different electrodes and their efficiency for modulating the refractive index. We believe that this study will pave a new path for future optoelectronic applications.

  8. Bismuth titanate nanorods and their visible light photocatalytic properties

    Pei, L.Z.; Liu, H.D.; Lin, N.; Yu, H.Y.

    2015-01-01

    Highlights: • Bismuth titanate nanorods have been synthesized by a simple hydrothermal process. • The size of bismuth titanate nanorods can be controlled by growth conditions. • Bismuth titanate nanorods show good photocatalytic activities of methylene blue and Rhodamine B. - Abstract: Bismuth titanate nanorods have been prepared using a facile hydrothermal process without additives. The bismuth titanate products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and UV-vis diffusion reflectance spectrum. XRD pattern shows that the bismuth titanate nanorods are composed of cubic Bi 2 Ti 2 O 7 phase. Electron microscopy images show that the length and diameter of the bismuth titanate nanorods are 50-200 nm and 2 μm, respectively. Hydrothermal temperature and reaction time play important roles on the formation and size of the bismuth titanate nanorods. UV-vis diffusion reflectance spectrum indicates that bismuth titanate nanorods have a band gap of 2.58 eV. The bismuth titanate nanorods exhibit good photocatalytic activities in the photocatalytic degradation of methylene blue (MB) and Rhodamine B (RB) under visible light irradiation. The bismuth titanate nanorods with cubic Bi 2 Ti 2 O 7 phase are a promising candidate as a visible light photocatalyst

  9. Metal oxide nanorod arrays on monolithic substrates

    Gao, Pu-Xian; Guo, Yanbing; Ren, Zheng

    2018-01-02

    A metal oxide nanorod array structure according to embodiments disclosed herein includes a monolithic substrate having a surface and multiple channels, an interface layer bonded to the surface of the substrate, and a metal oxide nanorod array coupled to the substrate surface via the interface layer. The metal oxide can include ceria, zinc oxide, tin oxide, alumina, zirconia, cobalt oxide, and gallium oxide. The substrate can include a glass substrate, a plastic substrate, a silicon substrate, a ceramic monolith, and a stainless steel monolith. The ceramic can include cordierite, alumina, tin oxide, and titania. The nanorod array structure can include a perovskite shell, such as a lanthanum-based transition metal oxide, or a metal oxide shell, such as ceria, zinc oxide, tin oxide, alumina, zirconia, cobalt oxide, and gallium oxide, or a coating of metal particles, such as platinum, gold, palladium, rhodium, and ruthenium, over each metal oxide nanorod. Structures can be bonded to the surface of a substrate and resist erosion if exposed to high velocity flow rates.

  10. Electrophoretic growth of lead zirconate titanate nanorods

    Limmer, S.J.; Seraji, S.; Forbess, M.J.; Wu Yun; Chou, T.P.; Nguyen, C.; Cao Guozhong [Washington Univ., Seattle, WA (United States). Dept. of Materials Science and Engineering

    2001-08-16

    Nanorods of lead zirconate titanate (PZT)-a ferro- and piezoelectric material-up to 10 {mu}m in length and 70 to 150 nm in diameter are produced by sol-gel electrophoresis of PZT in a track-etched polycarbonate membrane, which is used as a template. (orig.)

  11. TiO2 nanorods/PMMA copolymer-based nanocomposites: highly homogeneous linear and nonlinear optical material

    Sciancalepore, C; Agostiano, A; Cassano, T; Valentini, A; Curri, M L; Striccoli, M; Mecerreyes, D; Tommasi, R

    2008-01-01

    Original nanocomposites have been obtained by direct incorporation of pre-synthesized oleic acid capped TiO 2 nanorods into properly functionalized poly(methyl methacrylate) copolymers, carrying carboxylic acid groups on the repeating polymer unit. The presence of carboxylic groups on the alkyl chain of the host functionalized copolymer allows an highly homogeneous dispersion of the nanorods in the organic matrix. The prepared TiO 2 /PMMA-co-MA nanocomposites show high optical transparency in the visible region, even at high TiO 2 nanorod content, and tunable linear refractive index depending on the nanoparticle concentration. Finally measurements of nonlinear optical properties of TiO 2 polymer nanocomposites demonstrate a negligible two-photon absorption and a negative value of nonlinear refractive index, highlighting the potential of the nanocomposite for efficient optical devices operating in the visible region

  12. TiO2 nanorods/PMMA copolymer-based nanocomposites: highly homogeneous linear and nonlinear optical material

    Sciancalepore, C.; Cassano, T.; Curri, M. L.; Mecerreyes, D.; Valentini, A.; Agostiano, A.; Tommasi, R.; Striccoli, M.

    2008-05-01

    Original nanocomposites have been obtained by direct incorporation of pre-synthesized oleic acid capped TiO2 nanorods into properly functionalized poly(methyl methacrylate) copolymers, carrying carboxylic acid groups on the repeating polymer unit. The presence of carboxylic groups on the alkyl chain of the host functionalized copolymer allows an highly homogeneous dispersion of the nanorods in the organic matrix. The prepared TiO2/PMMA-co-MA nanocomposites show high optical transparency in the visible region, even at high TiO2 nanorod content, and tunable linear refractive index depending on the nanoparticle concentration. Finally measurements of nonlinear optical properties of TiO2 polymer nanocomposites demonstrate a negligible two-photon absorption and a negative value of nonlinear refractive index, highlighting the potential of the nanocomposite for efficient optical devices operating in the visible region.

  13. Slanted n-ZnO/p-GaN nanorod arrays light-emitting diodes grown by oblique-angle deposition

    Ya-Ju Lee

    2014-05-01

    Full Text Available High-efficient ZnO-based nanorod array light-emitting diodes (LEDs were grown by an oblique-angle deposition scheme. Due to the shadowing effect, the inclined ZnO vapor-flow was selectively deposited on the tip surfaces of pre-fabricated p-GaN nanorod arrays, resulting in the formation of nanosized heterojunctions. The LED architecture composed of the slanted n-ZnO film on p-GaN nanorod arrays exhibits a well-behaving current rectification of junction diode with low turn-on voltage of 4.7 V, and stably emits bluish-white luminescence with dominant peak of 390 nm under the operation of forward injection currents. In general, as the device fabrication does not involve passivation of using a polymer or sophisticated material growth techniques, the revealed scheme might be readily applied on other kinds of nanoscale optoelectronic devices.

  14. Chemical synthesis of CdS onto TiO2 nanorods for quantum dot sensitized solar cells

    Pawar, Sachin A.; Patil, Dipali S.; Lokhande, Abhishek C.; Gang, Myeng Gil; Shin, Jae Cheol; Patil, Pramod S.; Kim, Jin Hyeok

    2016-08-01

    A quantum dot sensitized solar cell (QDSSC) is fabricated using hydrothermally grown TiO2 nanorods and successive ionic layer adsorption and reaction (SILAR) deposited CdS. Surface morphology of the TiO2 films coated with different SILAR cycles of CdS is examined by Scanning Electron Microscopy which revealed aggregated CdS QDs coverage grow on increasing onto the TiO2 nanorods with respect to cycle number. Under AM 1.5G illumination, we found the TiO2/CdS QDSSC photoelectrode shows a power conversion efficiency of 1.75%, in an aqueous polysulfide electrolyte with short-circuit photocurrent density of 4.04 mA/cm2 which is higher than that of a bare TiO2 nanorods array.

  15. SILAR controlled CdSe nanoparticles sensitized ZnO nanorods photoanode for solar cell application: Electrolyte effect.

    Nikam, Pratibha R; Baviskar, Prashant K; Majumder, Sutripto; Sali, Jaydeep V; Sankapal, Babasaheb R

    2018-08-15

    Controlled growth of different sizes of cadmium selenide (CdSe) nanoparticles over well aligned ZnO nanorods have been performed using successive ionic layer adsorption and reaction (SILAR) technique at room temperature (27 °C) in order to form nano heterostructure solar cells. Deposition of compact layer of zinc oxide (ZnO) by SILAR technique on fluorine doped tin oxide (FTO) coated glass substrate followed by growth of vertically aligned ZnO nanorods array using chemical bath deposition (CBD) at low temperature (SILAR cycles for CdSe and with use of different electrolytes have been recorded as J-V characteristics and the maximum conversion efficiency of 0.63% have been attained with ferro/ferri cyanide electrolyte for 12 cycles CdSe coating over 1-D ZnO nanorods. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Lightweight concrete blocks with EVA recycled aggregate: a contribution to the thermal efficiency of building external walls

    De Melo, A. B.

    2013-12-01

    Full Text Available The regions with lots of shoe production suffer environmental impacts from waste generation during manufacturing of insoles and outsoles. Research conducted in Brazil has demonstrated the technical feasibility to recycle these wastes, especially Ethylene Vinyl Acetate (EVA, as lightweight aggregate, in the production of non-structural cement blocks. This article presents an evaluation of thermal performance with measurements of temperature variation in mini walls (1 m2 built with different materials, including various kinds of EVA block and ceramic bricks. Tests have shown efficient thermal performance for masonry blocks with EVA. These results and supplementary estimates contribute to add value to the EVA block, considering that there are good expectations that the component, with the new geometry proposed, can contribute to the energy efficiency of buildings, highlighting its suitability to most Brazilian bioclimatic regions.Las regiones con una gran producción de calzado sufren impactos ambientales derivados de la generación de residuos durante la producción de plantillas y suelas. Investigaciones realizadas en Brasil han demostrado la viabilidad técnica para el reciclaje de estos residuos, especialmente el Etileno Vinil Acetato (EVA, como agregado ligero en la fabricación de bloques de hormigón no estructurales. Este trabajo presenta una evaluación del rendimiento térmico, con mediciones de la variación de la temperatura en pequeñas paredes (1 m2 construidas con diversos materiales, incluyendo algunos tipos de bloques EVA y ladrillos de cerámica. Las pruebas demostraron actuaciones térmicas eficientes para las muestras con bloques EVA. Estos resultados y cálculos adicionales contribuyen con un aporte de valor añadido al bloque EVA, considerando que existen buenas expectativas del componente, con una nueva propuesta de geometría, pudiendo contribuir a la eficiencia energética de edificios, especialmente por su adecuación a la

  17. Monodispersed fabrication and dielectric studies on ethylenediamine passivated α-manganese dioxide nanorods

    Joseph, A. Martin [Research and Development Centre, Bharathiar University, Coimbatore, Tamilnadu (India); Kumar, R. Thilak, E-mail: manojthilak@yahoo.com [Periyar Arts College, Cuddalore-607001, Tamilnadu (India)

    2016-09-15

    Highlights: • Monodispersed ethylenediamine (EDA) passivated α-MnO{sub 2} nanorods were fabricated by inexpensive wet chemical method. • FTIR analysis indicated that surface passivation is strongly influenced by the introduction of the organic ligand. • XRD and HR-SEM revealed the structure and morphology of the fabricated α-MnO{sub 2} nanorods with an average size of about 40 × 200 nm. • Dielectric studies pointed out that the fabricated α-MnO{sub 2} is semiconducting in nature with resistivity, ρ = 1.46 to 5.76 × 10{sup 3} Ωcm. • The optical energy gap for the fabricated α-MnO{sub 2} nanorods is found to be around 1.37 eV. - Abstract: In this present work, pure α-MnO{sub 2} nanorods were fabricated by the reduction of 0.2 m/L of KMnO{sub 4} with 0.2 m/L of Na{sub 2}S{sub 2}O{sub 3}·5H{sub 2}O and by passivating with the organic ligand Ethylenediamine (EDA). The structural, functional, morphological and chemical composition of the nanorods were investigated by X-Ray Diffractometer (XRD), Fourier Transform Infrared Spectrometer (FTIR), High Resolution Scanning Electron Microscope (HR-SEM) and Energy Dispersive X-Ray Spectrometry (EDX). The XRD analysis indicated high crystalline nature of the product and FTIR confirmed the contribution of the organic ligand in surface passivation. HR-SEM image revealed the morphology of the α-MnO{sub 2} nanorods with an average size of about 40 × 200 nm. EDX confirmed the presence of Mn and O in the material. UV–visible spectrophotometery was used to determine the absorption behavior of the nanorods and an indirect band gap of 1.37 eV was acquired by Taucplot. Dielectric studies were carried out using Broadband Dielectric Spectrometer(BDS) and the resistivity was found to be around the semiconductor range (ρ = 1.46 to 5.76 × 10{sup 3} Ωcm).

  18. Ion-assisted functional monolayer coating of nanorod arrays in hydrogen plasmas

    Tam, E.; Levchenko, I.; Ostrikov, K.; Keidar, M.; Xu, S.

    2007-01-01

    Uniformity of postprocessing of large-area, dense nanostructure arrays is currently one of the greatest challenges in nanoscience and nanofabrication. One of the major issues is to achieve a high level of control in specie fluxes to specific surface areas of the nanostructures. As suggested by the numerical experiments in this work, this goal can be achieved by manipulating microscopic ion fluxes by varying the plasma sheath and nanorod array parameters. The dynamics of ion-assisted deposition of functional monolayer coatings onto two-dimensional carbon nanorod arrays in a hydrogen plasma is simulated by using a multiscale hybrid numerical simulation. The numerical results show evidence of a strong correlation between the aspect ratios and nanopattern positioning of the nanorods, plasma sheath width, and densities and distributions of microscopic ion fluxes. When the spacing between the nanorods and/or their aspect ratios are larger, and/or the plasma sheath is wider, the density of microscopic ion current flowing to each of the individual nanorods increases, thus reducing the time required to apply a functional monolayer coating down to 11 s for a 7-μm-wide sheath, and to 5 s for a 50-μm-wide sheath. The computed monolayer coating development time is consistent with previous experimental reports on plasma-assisted functionalization of related carbon nanostructures [B. N. Khare et al., Appl. Phys. Lett. 81, 5237 (2002)]. The results are generic in that they can be applied to a broader range of plasma-based processes and nanostructures, and contribute to the development of deterministic strategies of postprocessing and functionalization of various nanoarrays for nanoelectronic, biomedical, and other emerging applications

  19. Pyrrole-regulated precipitation of titania nanorods on polymer fabrics for photocatalytic degradation of trace toluene in air

    Gu, Yi-Jie; Wen, Wei; Xu, Yang; Wu, Jin-Ming

    2018-03-01

    When compared with nanoparticulate counterparts, TiO2 thin films with vertically aligned one-dimensional (1D) nanostructures exhibit enhanced photocatalytic activity because of the highly accessible surface area. The perpendicular of the 1D nanostructure reduces the charge migration path and hence the carrier recombination rate, which also contributes to the photocatalytic activity. Furthermore, TiO2 thin films on flexible substrates are more suitable to degrade pollutants in either water or air because of its easy recovery and free-bending shape. In this study, flexible polyethylene fabrics were firstly coated with a sol-gel nanoparticulate TiO2 seed layer. Quasi-aligned TiO2 nanorods were then precipitated homogeneously under an atmospheric pressure and a low temperature not exceeding 80 °C, using a peroxy-titanium complex precursor with the additive of pyrrole. It is found that the density of TiO2 nanorods increased with the increasing amount of pyrrole monomers. The resultant TiO2 film on polyethylene fabrics exhibited a much reduced band gap of ca. 2.86 eV, which can be attributed to the surface oxygen deficiencies. When utilized to assist photocatalytic degradation of trace toluene in air under the UV light illumination, the TiO2 film exhibited a gradually increased photocatalytic activity upon the increasing cycles for up to six, because of the gradual removal of trace organics on the TiO2 surface. The highest photocatalytic efficiency is recorded to be 5 times that of TiO2 nanotube arrays, which are regarded as an excellent photocatalyst for air cleaning.

  20. The Qualities Needed for a Successful Collaboration: A Contribution to the Conceptual Understanding of Collaboration for Efficient Public Transport

    Robert Hrelja

    2016-06-01

    Full Text Available The creation of an efficient public transport system requires collaborations between formal independent organizations. This paper examines collaborations between public and private organizations and passengers, with the aim of contributing to the conceptual understanding of collaborations on public transport. The study begins by describing previous research on collaboration in the public transport area and in other research fields analytically relevant for public transport. Accordingly, collaboration is defined as an attempt to overcome problems with collective action and to transform a situation in which the various organizations operate independently into a situation where they act in concert to achieve shared objectives. The collaboration process involves the establishment of joint rules and structures that govern the relationship and behavior of the organizations. According to this definition, collaboration is a more sophisticated form of collective action than is indicated by terms such as “co-operation” or “coordination”. Fully-functioning collaboration can be described as a form of “co-action”, as opposed to “individual action”. In co-action, formal independent organizations together reap the benefits of working together and achieve more than if they had acted alone. Co-action can be regarded as a gradual trust-building process that requires qualities such as mutual confidence, an understanding of other organizations’ motivations, and joint problem formulation.

  1. Low temperature grown ZnO@TiO{sub 2} core shell nanorod arrays for dye sensitized solar cell application

    Goh, Gregory Kia Liang [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology, and Research), 3 Research Link, 117602 Singapore (Singapore); Le, Hong Quang, E-mail: lehq@imre.a-star.edu.sg [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology, and Research), 3 Research Link, 117602 Singapore (Singapore); Huang, Tang Jiao; Hui, Benjamin Tan Tiong [Department of Materials Science and Engineering (DMSE), Faculty of Engineering National University of Singapore (NUS) BLK E3A, #04-10, 7 Engineering Drive 1, Singapore 117574 (Singapore)

    2014-06-01

    High aspect ratio ZnO nanorod arrays were synthesized on fluorine-doped tin oxide glasses via a low temperature solution method. By adjusting the growth condition and adding polyethylenimine, ZnO nanorod arrays with tunable length were successfully achieved. The ZnO@TiO{sub 2} core shells structures were realized by a fast growth method of immersion into a (NH{sub 4}){sub 2}·TiF{sub 6} solution. Transmission electron microscopy, X-ray Diffraction and energy dispersive X-ray measurements all confirmed the existence of a titania shell uniformly covering the ZnO nanorod's surface. Results of solar cell testing showed that addition of a TiO{sub 2} shell to the ZnO nanorod significantly increased short circuit current (from 4.2 to 5.2 mA/cm{sup 2}), open circuit voltage (from 0.6 V to 0.8 V) and fill factor (from 42.8% to 73.02%). The overall cell efficiency jumped from 1.1% for bare ZnO nanorod to 3.03% for a ZnO@TiO{sub 2} core shell structured solar cell with a 18–22 nm shell thickness, a nearly threefold increase. - Graphical abstract: The synthesis process of coating TiO{sub 2} shell onto ZnO nanorod core is shown schematically. A thin, uniform, and conformal shell had been grown on the surface of the ZnO core after immersing in the (NH{sub 4}){sub 2}·TiF{sub 6} solution for 5–15 min. - Highlights: • ZnO@TiO{sub 2} core shell nanorod has been grown on FTO substrate using low temperature solution method. • TEM, XRD, EDX results confirmed the existing of titana shell, uniformly covered rod's surface. • TiO{sub 2} shell suppressed recombination, demonstrated significant enhancement in cell's efficiency. • Core shell DSSC's efficiency achieved as high as 3.03%, 3 times higher than that of ZnO nanorods.

  2. High rate flame synthesis of highly crystalline iron oxide nanorods

    Merchan-Merchan, W; Taylor, A M; Saveliev, A V

    2008-01-01

    Single-step flame synthesis of iron oxide nanorods is performed using iron probes inserted into an opposed-flow methane oxy-flame. The high temperature reacting environment of the flame tends to convert elemental iron into a high density layer of iron oxide nanorods. The diameters of the iron oxide nanorods vary from 10 to 100 nm with a typical length of a few microns. The structural characterization performed shows that nanorods possess a highly ordered crystalline structure with parameters corresponding to cubic magnetite (Fe 3 O 4 ) with the [100] direction oriented along the nanorod axis. Structural variations of straight nanorods such as bends, and T-branched and Y-branched shapes are frequently observed within the nanomaterials formed, opening pathways for synthesis of multidimensional, interconnected networks

  3. Enhanced Light Output of Dipole Source in GaN-Based Nanorod Light-Emitting Diodes by Silver Localized Surface Plasmon

    Huamao Huang

    2014-01-01

    Full Text Available The light output of dipole source in three types of light-emitting diodes (LEDs, including the conventional planar LED, the nanorod LED, and the localized surface plasmon (LSP assisted LED by inserting silver nanoparticles in the gaps between nanorods, was studied by use of two-dimensional finite difference time domain method. The height of nanorod and the size of silver nanoparticles were variables for discussion. Simulation results show that a large height of nanorod induces strong wavelength selectivity, which can be significantly enhanced by LSP. On condition that the height of nanorod is 400 nm, the diameter of silver nanoparticle is 100 nm, and the wavelength is 402.7 nm, the light-output efficiency for LSP assisted LED is enhanced by 190% or 541% as compared to the nanorod counterpart or the planar counterpart, respectively. The space distribution of Poynting vector was present to demonstrate the significant enhancement of light output at the resonant wavelength of LSP.

  4. Sulfur and Nitrogen co-doped graphene quantum dot decorated ZnO nanorod/polymer hybrid flexible device for photosensing applications

    Hmar, Jehova Jire L.; Majumder, Tanmoy; Dhar, Saurab; Mondal, Suvra Prakash, E-mail: suvraphy@gmail.com

    2016-08-01

    S and N co-doped graphene quantum dots (S,N-GQDs) have been synthesized by a hydrothermal process. S,N-GQDs are made up of 1–5 monolayer of graphene with average diameter 13.3 nm. The absorption peaks at 336 and 621 nm, are attributed to n → Π{sup ⁎} transitions of electrons in C=O and S=O bonds, respectively. S,N-GQDs are highly luminescent and showed excitation dependent emission behaviors. Hybrid photosensing device has been fabricated with S,N-GQD sensitized ZnO nanorods and a conjugated polymer poly(3-hexylthiophene) (P3HT). S,N-GQD decorated ZnO nanorod demonstrated higher photoresponse compared to pristine ZnO nanorod based device. S,N-GQD/ZnO nanorod hybrid device showed superior incident photon to electron conversion efficiency (IPCE), photoresponsivity and detectivity compared to the control samples. The flexibility study of the samples has been monitored by measuring current-voltage characteristics at different bending angles. - Highlights: • S and N co-doped graphene quantum dots (S,N-GQDs) were synthesized. • ZnO nanorods were grown on ITO coated flexible PET substrates. • S,N-GQDs were attached with ZnO nanorods and used as a green sensitizer. • Photosensing properties of S,N-GQD/ZnO and P3HT polymer hybrid device was studied.

  5. A novel ammonia complex-assisted ion-exchange strategy to fabricate heterostructured PdO/TiO{sub 2} nanorods with enhanced photocatalytic activities

    Shi, Liang, E-mail: shiliang19870917@163.com [Ocean University of China, College of Chemistry and Chemical Engineering (China); Han, Qian, E-mail: 120339369@qq.com [Ocean University of China, Institute of Materials Science and Engineering (China); Cao, Lixin, E-mail: caolixin@ouc.edu.cn [Ocean University of China, College of Chemistry and Chemical Engineering (China); Zhao, Fenghuan, E-mail: 1029581171@qq.com [Ocean University of China, Institute of Materials Science and Engineering (China); Xia, Chenghui, E-mail: c.xia@uu.nl [Ocean University of China, College of Chemistry and Chemical Engineering (China); Dong, Bohua, E-mail: dongbohua@ouc.edu.cn; Xi, Yaoning, E-mail: 464985694@qq.com [Ocean University of China, Institute of Materials Science and Engineering (China)

    2016-12-15

    Heterojunctions have been often employed to improve the photocatalytic behavior of titania-based materials. Herein, we propose a novel strategy to fabricate PdO/TiO{sub 2} heterostructured nanorods, as PdO was proved to be an efficient co-catalyst in photocatalytic reactions. Primarily, ammonia complex-assisted ion-exchange method was used to store Pd(II) ions in protonated titanate nanotubes, as which cannot be replaced by metallic cations via traditional route. Then, PdO/TiO{sub 2} heterojunctions formed through calcination in air, as nanotubes dehydrated and shrank into nanorods. X-ray diffraction, Raman spectra, and X-ray photoelectron spectroscopy were used to demonstrate the formation of PdO component, and transmission electron microscopy was employed to prove the successful connection between TiO{sub 2} nanorods and PdO nanoparticles. Moreover, inductive coupled plasma proved excellent compositional gradient of Pd(II) in the PdO/TiO{sub 2} heterostructured nanorods. In the present work, the photocatalytic activities of PdO/TiO{sub 2} heterostructured nanorods were investigated by decoloring several dyes under UV illumination. Our research revealed appropriate PdO loading (1.0 wt%) enhanced photocatalytic performance compared with bare TiO{sub 2} nanorods, where PdO/TiO{sub 2} heterojunctions were responsible for the prohibitive photogenerated carries recombination.

  6. Zinc vanadate nanorods and their visible light photocatalytic activity

    Pei, L.Z.; Lin, N.; Wei, T.; Liu, H.D.; Yu, H.Y.

    2015-01-01

    Highlights: • Zinc vanadate nanorods have been synthesized by a facile hydrothermal process. • The size of zinc vanadate nanorods can be controlled by growth conditions. • Zinc vanadate nanorods show good photocatalytic activities of methylene blue under solar light. - Abstract: Zinc vanadate nanorods have been synthesized by a simple hydrothermal process using zinc acetate and sodium vanadate as the raw materials. The zinc vanadate nanorods have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and solid UV–vis diffuse reflectance spectrum. XRD pattern and HRTEM image show that the zinc vanadate nanorods are composed of single crystalline monoclinic Zn 2 V 2 O 7 phase. SEM and TEM observations show that the diameter and length of the zinc vanadate nanorods are 50–100 nm and about 5 μm, respectively. Sodium dodecyl sulfonate (SDS) has an essential role in the formation of zinc vanadate nanorods. The SDS-assisted nucleation and growth process have been proposed to explain the formation and growth of the zinc vanadate nanorods. Solid UV–vis diffuse reflectance spectrum shows that the zinc vanadate nanorods have a band gap of 2.76 eV. The photocatalytic activities of the zinc vanadate nanorods have been evaluated by the photocatalytic degradation of methylene blue (MB) under solar light irradiation. The MB with the concentration of 10 mg L −1 can be degraded totally under the solar light irradiation for 4 h. It is suggested that the zinc vanadate nanorods exhibit promising application potential for the degradation of organic pollutants under solar light irradiation

  7. Facile electrochemical synthesis of tellurium nanorods and their photoconductive properties

    Li, H.H. [Center for Photon Manufacturing Science and Technology, School of Materials Science and Engineering, Jiangsu University, Zhenjiang - 212013 (China); Zhang, P. [Dongguan University of Technology, Dongguan-523808 (China); School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou - 510275 (China); Liang, C.L. [Instrumental Analysis and Research Center, SunYat-sen University, Guangzhou - 510275 (China); Yang, J. [School of Materials Science and Engineering, Jiangsu University, Zhenjiang - 212013 (China); Zhou, M. [Center for Photon Manufacturing Science and Technology, School of Materials Science and Engineering, Jiangsu University, Zhenjiang - 212013 (China); The State Key Laboratory of Tribology, Tsinghua University, Beijing - 10084 (China); Lu, X.H. [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou - 510275 (China); Hope, G.A. [School of Biomolecular and Physical Sciences, Griffith University, Nathan - Qld 4111 (Australia)

    2012-10-15

    Tellurium nanorods have been successfully fabricated by template and surfactant-free electrochemical technique from an aqueous solution at room temperature. The as-prepared tellurium nanorods were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectrometry, UV-vis spectroscopy and photoluminescence spectroscopy. Films based on tellurium nanorods were constructed to study the photoresponse and I-V curves. These photoresponse measurements demonstrate that tellurium nanorods exhibited enhanced conductivity under illumination compared to in the dark measurement. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. A simple route to synthesize manganese germanate nanorods

    Pei, L.Z.; Yang, Y.; Yuan, C.Z.; Duan Taike; Zhang Qianfeng

    2011-01-01

    Manganese germanate nanorods have been synthesized by a simple route using germanium dioxide and manganese acetate as the source materials. X-ray diffraction observation shows that the nanorods are composed of orthorhombic and monoclinic manganese germanate phases. Scanning electron microscopy and transmission electron microscopy observations display that the manganese germanate nanorods have flat tips with the length of longer than 10 micrometers and diameter of 60-350 nm, respectively. The role of the growth conditions on the formation of the manganese germanate nanorods shows that the proper selection and combination of the growth conditions are the key factor for controlling the formation of the manganese germanate nanorods. The photoluminescence spectrum of the manganese germanate nanorods exhibits four fluorescence emission peaks centered at 422 nm, 472 nm, 487 nm and 530 nm showing the application potential for the optical devices. - Research Highlights: → Manganese germanate nanorods have been synthesized by simple hydrothermal process. → The formation of manganese germanate nanorods can be controlled by growth conditions. → Manganese germanate nanorods exhibit good PL emission ability for optical device.

  9. Growth of KOH etched AZO nanorods and investigation of its back scattering effect in thin film a-Si solar cell

    Sharma, Jayasree Roy; Mitra, Suchismita; Ghosh, Hemanta; Das, Gourab; Bose, Sukanta; Mandal, Sourav; Mukhopadhyay, Sumita; Saha, Hiranmay; Barua, A. K.

    2018-02-01

    In order to increase the stabilized efficiencies of thin film silicon (TFS) solar cells it is necessary to use better light management techniques. Texturization by etching of sputtered aluminum doped zinc oxide (Al:ZnO or AZO) films has opened up a variety of promises to optimize light trapping schemes. RF sputtered AZO film has been etched by potassium hydroxide (KOH). A systematic study of etching conditions such as etchant concentration, etching time, temperature management etc. have been performed in search of improved electrical and optical performances of the films. The change in etching conditions has exhibited a noticeable effect on the structure of AZO films for which the light trapping effect differs. After optimizing the etching conditions, nanorods have been found on the substrate. Hence, nanorods have been developed only by chemical etching, rather than the conventional development method (hydrothermal method, sol-gel method, electrolysis method etc.). The optimized etched substrate has 82% transmittance, moderate haze in the visible range and sheet resistance ∼13 (Ω/□). The developed nanorods (optimized etched substrate) provide better light trapping within the cell as the optical path length has been increased by using the nanorods. This provides an effect on carrier collection as well as the efficiency in a-Si solar cells. Finite difference time domain (FDTD) simulations have been performed to observe the light trapping by AZO nanorods formed on sputtered AZO films. For a p-i-n solar cell developed on AZO nanorods coated with sputtered AZO films, it has been found through simulations that, the incident light is back scattered into the absorbing layer, leading to an increase in photogenerated current and hence higher efficiency. It has been found that, the light that passes through the nanorods is not getting absorbed and maximum amount of light is back scattered towards the solar cell.

  10. On the growth and photocatalytic activity of the vertically aligned ZnO nanorods grafted by CdS shells

    Zirak, M. [Department of Physics, Sharif University of Technology, P.O. Box 11555-9161, Tehran (Iran, Islamic Republic of); Moradlou, O. [Department of Chemistry, Faculty of Sciences, Alzahra University, P.O. Box 1993893973, Tehran (Iran, Islamic Republic of); Bayati, M.R. [Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695-7907 (United States); Nien, Y.T. [Department of Materials Science and Engineering, National Formosa University, Huwei District, Taiwan (China); Moshfegh, A.Z., E-mail: moshfegh@sharif.edu [Department of Physics, Sharif University of Technology, P.O. Box 11555-9161, Tehran (Iran, Islamic Republic of); Institute of Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-8969, Tehran (Iran, Islamic Republic of)

    2013-05-15

    We have studied systematically photocatalytic properties of the vertically aligned ZnO@CdS core–shell nanorods where the features were grown through a multistep procedure including sol–gel for the formation of ZnO seed layer, hydrothermal process to grow ZnO nanorods, and successive ion layer adsorption and reaction (SILAR) process to deposit CdS nanoshells onto the ZnO nanorods. Formation of the ZnO seed layer and vertically aligned ZnO nanorods (d ∼ 40 nm) with a hexagonal cross-section was confirmed by AFM and SEM imaging. Successful capping of ZnO nanorods with homogeneous CdS nanocrystallites (∼5 nm) was ascertained by HRTEM diffraction and imaging. Optical properties of the samples were also studied using UV–vis spectrophotometry. It was found that the absorption edge of the CdS shell has a red shift when its thickness increases. Photocatalytic activity of the samples was examined by photodecomposition of methylene blue under UV and visible lights where the maximum reaction rate constant was found to be 0.012 min{sup −1} under UV illumination and 0.007 min{sup −1} under visible light. The difference in catalytic activities of the ZnO@CdS core–shell nanorods under UV and visible irradiations was explained based upon the electronic structure as well as the arrangement of the energy levels in the ZnO@CdS core–shells. It is shown that the structure and photocatalytic efficiency of the samples can be tuned by manipulating the SILAR variables.

  11. On the growth and photocatalytic activity of the vertically aligned ZnO nanorods grafted by CdS shells

    Zirak, M.; Moradlou, O.; Bayati, M. R.; Nien, Y. T.; Moshfegh, A. Z.

    2013-05-01

    We have studied systematically photocatalytic properties of the vertically aligned ZnO@CdS core-shell nanorods where the features were grown through a multistep procedure including sol-gel for the formation of ZnO seed layer, hydrothermal process to grow ZnO nanorods, and successive ion layer adsorption and reaction (SILAR) process to deposit CdS nanoshells onto the ZnO nanorods. Formation of the ZnO seed layer and vertically aligned ZnO nanorods (d ∼ 40 nm) with a hexagonal cross-section was confirmed by AFM and SEM imaging. Successful capping of ZnO nanorods with homogeneous CdS nanocrystallites (∼5 nm) was ascertained by HRTEM diffraction and imaging. Optical properties of the samples were also studied using UV-vis spectrophotometry. It was found that the absorption edge of the CdS shell has a red shift when its thickness increases. Photocatalytic activity of the samples was examined by photodecomposition of methylene blue under UV and visible lights where the maximum reaction rate constant was found to be 0.012 min-1 under UV illumination and 0.007 min-1 under visible light. The difference in catalytic activities of the ZnO@CdS core-shell nanorods under UV and visible irradiations was explained based upon the electronic structure as well as the arrangement of the energy levels in the ZnO@CdS core-shells. It is shown that the structure and photocatalytic efficiency of the samples can be tuned by manipulating the SILAR variables.

  12. On the growth and photocatalytic activity of the vertically aligned ZnO nanorods grafted by CdS shells

    Zirak, M.; Moradlou, O.; Bayati, M.R.; Nien, Y.T.; Moshfegh, A.Z.

    2013-01-01

    We have studied systematically photocatalytic properties of the vertically aligned ZnO@CdS core–shell nanorods where the features were grown through a multistep procedure including sol–gel for the formation of ZnO seed layer, hydrothermal process to grow ZnO nanorods, and successive ion layer adsorption and reaction (SILAR) process to deposit CdS nanoshells onto the ZnO nanorods. Formation of the ZnO seed layer and vertically aligned ZnO nanorods (d ∼ 40 nm) with a hexagonal cross-section was confirmed by AFM and SEM imaging. Successful capping of ZnO nanorods with homogeneous CdS nanocrystallites (∼5 nm) was ascertained by HRTEM diffraction and imaging. Optical properties of the samples were also studied using UV–vis spectrophotometry. It was found that the absorption edge of the CdS shell has a red shift when its thickness increases. Photocatalytic activity of the samples was examined by photodecomposition of methylene blue under UV and visible lights where the maximum reaction rate constant was found to be 0.012 min −1 under UV illumination and 0.007 min −1 under visible light. The difference in catalytic activities of the ZnO@CdS core–shell nanorods under UV and visible irradiations was explained based upon the electronic structure as well as the arrangement of the energy levels in the ZnO@CdS core–shells. It is shown that the structure and photocatalytic efficiency of the samples can be tuned by manipulating the SILAR variables.

  13. Flexible organic/inorganic hybrid solar cells based on conjugated polymer and ZnO nanorod array

    Tong, Fei; Kim, Kyusang; Martinez, Daniel; Thapa, Resham; Ahyi, Ayayi; Williams, John; Park, Minseo; Kim, Dong-Joo; Lee, Sungkoo; Lim, Eunhee; Lee, Kyeong K

    2012-01-01

    We report on the photovoltaic characteristics of organic/inorganic hybrid solar cells fabricated on ‘flexible’ transparent substrates. The solar cell device is composed of ZnO nanorod array and the bulk heterojunction structured organic layer which is the blend of poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl C61 butyric acid methyl ester (PCBM). The ZnO nanorod array was grown on indium tin oxide (ITO)-coated polyethylene terephthalate (PET) substrates via a low-temperature (85 °C) aqueous solution process. The blend solution consisting of conjugated polymer P3HT and fullerene PCBM was spin coated at a low spinning rate of 400 rpm on top of the ZnO nanorod array structure and then the photoactive layer was slow dried at room temperature in air to promote its infiltration into the nanorod network. As a top electrode, silver was sputtered on top of the photoactive layer. The flexible solar cell with the structure of PET/ITO/ZnO thin film/ZnO nanorods/P3HT:PCBM/Ag exhibited a photovoltaic performance with an open circuit voltage (V OC ) of 0.52 V, a short circuit current density (J SC ) of 9.82 mA cm −2 , a fill factor (FF) of 35% and a power conversion efficiency (η) of 1.78%. All the measurements were performed under 100 mW cm −2 of illumination with an air mass 1.5 G filter. To the best of our knowledge, this is the first presentation of investigation into the fabrication and characterization of organic/inorganic hybrid solar cells based on bulk heterojunction structured conjugated polymer/fullerene photoactive layer and ZnO nanorod array constructed on flexible transparent substrates. (paper)

  14. Stability and biocompatibility of photothermal gold nanorods after lyophilization and sterilization

    Gomez, Leyre [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), C/ Mariano Esquillor, R and D Building, University of Zaragoza, 50018 Zaragoza (Spain); Cebrian, Virginia [CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, Zaragoza (Spain); Hospital Universitario La Paz-IdiPAZ, Paseo de la Castellana 261, 28046 Madrid (Spain); Martin-Saavedra, Francisco [Hospital Universitario La Paz-IdiPAZ, Paseo de la Castellana 261, 28046 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, Zaragoza (Spain); Arruebo, Manuel, E-mail: arruebom@unizar.es [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), C/ Mariano Esquillor, R and D Building, University of Zaragoza, 50018 Zaragoza (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, Zaragoza (Spain); Vilaboa, Nuria [Hospital Universitario La Paz-IdiPAZ, Paseo de la Castellana 261, 28046 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, Zaragoza (Spain); Santamaria, Jesus, E-mail: Jesus.Santamaria@unizar.es [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), C/ Mariano Esquillor, R and D Building, University of Zaragoza, 50018 Zaragoza (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, Zaragoza (Spain)

    2013-10-15

    Graphical abstract: - Highlights: • Morphological changes are observed for CTABr capped gold nanorods over time. • Polystyrenesulfonate (PSS) and polyethyleneglycol (PEG) coated nanorods are stable. • Re-suspendible and sterilizable colloids are prepared using those capping agents. • Those materials are efficient heat sinks potentially used in photothermal therapy. - Abstract: Suspensions in phosphate buffered saline (PBS) of gold nanorods stabilized with cetyltrimethyl ammonium chloride (CTABr), polystyrenesulfonate (PSS) and methyl-polyethyleneglycol-thiol (m-PEG-SH) have been prepared and the evolution of their colloidal stability and plasmonic response over time has been evaluated. Their performance after lyophilization, alcoholic sterilization and resuspension has also been characterized. Sub-cytotoxic doses on HeLa cells were calculated for the three surface functionalizations used. Their heating efficiency at different exposure times was also evaluated after being irradiated with near infrared light. The best results were obtained for m-PEG-SH stabilized rods, which were not only stable, sterilizable and lyophilizable, but also biocompatible at all doses tested, showing potential as a stable, re-suspendible and biocompatible hyperthermic agent.

  15. Synthesis of supported silver nano-spheres on zinc oxide nanorods for visible light photocatalytic applications

    Saoud, Khaled [Virginia Commonwealth University-Qatar, Doha (Qatar); Alsoubaihi, Rola [Virginia Commonwealth University, Richmond, VA (United States); Bensalah, Nasr [Qatar University, Doha (Qatar); Bora, Tanujjal [Chair in Nanotechnology, Water Research Center, Sultan Qaboos University, P.O. Box 33, Al-Khoudh-123 (Oman); Bertino, Massimo [Virginia Commonwealth University, Richmond, VA (United States); Dutta, Joydeep, E-mail: dutta@squ.edu.om [Chair in Nanotechnology, Water Research Center, Sultan Qaboos University, P.O. Box 33, Al-Khoudh-123 (Oman)

    2015-03-15

    Highlights: • Synthesis of supported Ag NPs on ZnO nanorods using open vessel microwave reactor. • Use of the Ag/ZnO NPs as an efficient visible light photocatalyst. • Complete degradation of methylene blue in 1 h with 0.5 g/L Ag/ZnO NPs. - Abstract: We report the synthesis of silver (Ag) nano-spheres (NS) supported on zinc oxide (ZnO) nanorods through two step mechanism, using open vessel microwave reactor. Direct reduction of ZnO from zinc nitrates was followed by deposition precipitation of the silver on the ZnO nanorods. The supported Ag/ZnO nanoparticles were then characterized by electron microscopy, X-ray diffraction, FTIR, photoluminescence and UV–vis spectroscopy. The visible light photocatalytic activity of Ag/ZnO system was investigated using a test contaminant, methylene blue (MB). Almost complete removal of MB in about 60 min for doses higher than 0.5 g/L of the Ag/ZnO photocatalyst was achieved. This significant improvement in the photocatalytic efficiency of Ag/ZnO photocatalyst under visible light irradiation can be attributed to the presence of Ag nanoparticles on the ZnO nanoparticles which greatly enhances absorption in the visible range of solar spectrum enabled by surface plasmon resonance effect from Ag nanoparticles.

  16. Self-Healing Thermal Annealing: Surface Morphological Restructuring Control of GaN Nanorods

    Conroy, Michele; Li, Haoning; Zubialevich, Vitaly Z.; Kusch, Gunnar; Schmidt, Michael; Collins, Timothy; Glynn, Colm; Martin, Robert W.; O’Dwyer, Colm; Morris, Michael D.; Holmes, Justin D.; Parbrook, Peter J.

    2016-12-07

    With advances in nanolithography and dry etching, top-down methods of nanostructuring have become a widely used tool for improving the efficiency of optoelectronics. These nano dimensions can offer various benefits to the device performance in terms of light extraction and efficiency, but often at the expense of emission color quality. Broadening of the target emission peak and unwanted yellow luminescence are characteristic defect-related effects due to the ion beam etching damage, particularly for III–N based materials. In this article we focus on GaN based nanorods, showing that through thermal annealing the surface roughness and deformities of the crystal structure can be “self-healed”. Correlative electron microscopy and atomic force microscopy show the change from spherical nanorods to faceted hexagonal structures, revealing the temperature-dependent surface morphology faceting evolution. The faceted nanorods were shown to be strain- and defect-free by cathodoluminescence hyperspectral imaging, micro-Raman, and transmission electron microscopy (TEM). In-situ TEM thermal annealing experiments allowed for real time observation of dislocation movements and surface restructuring observed in ex-situ annealing TEM sampling. This thermal annealing investigation gives new insight into the redistribution path of GaN material and dislocation movement post growth, allowing for improved understanding and in turn advances in optoelectronic device processing of compound semiconductors.

  17. Charge carrier dynamics and surface plasmon interaction in gold nanorod-blended organic solar cell

    Rana, Aniket; Lochan, Abhiram; Chand, Suresh; Kumar, Mahesh; Singh, Rajiv K.; Gupta, Neeraj; Sharma, G. D.

    2016-01-01

    The inclusion of plasmonic nanoparticles into organic solar cell enhances the light harvesting properties that lead to higher power conversion efficiency without altering the device configuration. This work defines the consequences of the nanoparticle overloading amount and energy transfer process between gold nanorod and polymer (active matrix) in organic solar cells. We have studied the hole population decay dynamics coupled with gold nanorods loading amount which provides better understanding about device performance limiting factors. The exciton and plasmon together act as an interacting dipole; however, the energy exchange between these two has been elucidated via plasmon resonance energy transfer (PRET) mechanism. Further, the charge species have been identified specifically with respect to their energy levels appearing in ultrafast time domain. The specific interaction of these charge species with respective surface plasmon resonance mode, i.e., exciton to transverse mode of oscillation and polaron pair to longitudinal mode of oscillations, has been explained. Thus, our analysis reveals that PRET enhances the carrier population density in polymer via non-radiative process beyond the concurrence of a particular plasmon resonance oscillation mode and polymer absorption range. These findings give new insight and reveal specifically the factors that enhance and control the performance of gold nanorods blended organic solar cells. This work would lead in the emergence of future plasmon based efficient organic electronic devices.

  18. Charge carrier dynamics and surface plasmon interaction in gold nanorod-blended organic solar cell

    Rana, Aniket; Gupta, Neeraj; Lochan, Abhiram; Sharma, G. D.; Chand, Suresh; Kumar, Mahesh; Singh, Rajiv K.

    2016-08-01

    The inclusion of plasmonic nanoparticles into organic solar cell enhances the light harvesting properties that lead to higher power conversion efficiency without altering the device configuration. This work defines the consequences of the nanoparticle overloading amount and energy transfer process between gold nanorod and polymer (active matrix) in organic solar cells. We have studied the hole population decay dynamics coupled with gold nanorods loading amount which provides better understanding about device performance limiting factors. The exciton and plasmon together act as an interacting dipole; however, the energy exchange between these two has been elucidated via plasmon resonance energy transfer (PRET) mechanism. Further, the charge species have been identified specifically with respect to their energy levels appearing in ultrafast time domain. The specific interaction of these charge species with respective surface plasmon resonance mode, i.e., exciton to transverse mode of oscillation and polaron pair to longitudinal mode of oscillations, has been explained. Thus, our analysis reveals that PRET enhances the carrier population density in polymer via non-radiative process beyond the concurrence of a particular plasmon resonance oscillation mode and polymer absorption range. These findings give new insight and reveal specifically the factors that enhance and control the performance of gold nanorods blended organic solar cells. This work would lead in the emergence of future plasmon based efficient organic electronic devices.

  19. Stability and biocompatibility of photothermal gold nanorods after lyophilization and sterilization

    Gomez, Leyre; Cebrian, Virginia; Martin-Saavedra, Francisco; Arruebo, Manuel; Vilaboa, Nuria; Santamaria, Jesus

    2013-01-01

    Graphical abstract: - Highlights: • Morphological changes are observed for CTABr capped gold nanorods over time. • Polystyrenesulfonate (PSS) and polyethyleneglycol (PEG) coated nanorods are stable. • Re-suspendible and sterilizable colloids are prepared using those capping agents. • Those materials are efficient heat sinks potentially used in photothermal therapy. - Abstract: Suspensions in phosphate buffered saline (PBS) of gold nanorods stabilized with cetyltrimethyl ammonium chloride (CTABr), polystyrenesulfonate (PSS) and methyl-polyethyleneglycol-thiol (m-PEG-SH) have been prepared and the evolution of their colloidal stability and plasmonic response over time has been evaluated. Their performance after lyophilization, alcoholic sterilization and resuspension has also been characterized. Sub-cytotoxic doses on HeLa cells were calculated for the three surface functionalizations used. Their heating efficiency at different exposure times was also evaluated after being irradiated with near infrared light. The best results were obtained for m-PEG-SH stabilized rods, which were not only stable, sterilizable and lyophilizable, but also biocompatible at all doses tested, showing potential as a stable, re-suspendible and biocompatible hyperthermic agent

  20. Influence of fluorescence of Eu(dbm)3phen doped films by gold nanorods

    Wang, Qingru; Shi, Qiang; Li, Shuhong; Zhang, Dong; Wang, Wenjun

    2016-01-01

    The gold nanorods (AuNRs) were precipitated on Eu(dbm) 3 phen doped films by different spin rates. The plasmonic enhancement and quenching effects of gold nanorods on the fluorescence of Eu(dbm) 3 phen were both demonstrated. The enhancement on the fluorescence is sensitive to the distribution of the AuNRs. Both fluorescence enhancement mechanisms, i.e. increase of the intense absorption of ligands and increase of quantum efficiency, promote the 20 fold enhancement, at which the excitation wavelength red-shifts from 362 nm to 372 nm. Higher absorption of ligands in the complex due to the AuNRs caused the bathochromic shift of excitation peak. The quenching factor at 612 nm reached to 0.47.

  1. DNA origami/gold nanorod hybrid nanostructures for the circumvention of drug resistance.

    Song, Linlin; Jiang, Qiao; Liu, Jianbing; Li, Na; Liu, Qing; Dai, Luru; Gao, Yuan; Liu, Weili; Liu, Dongsheng; Ding, Baoquan

    2017-06-14

    We herein demonstrate that DNA origami can work as a multifunctional platform integrating a chemotherapeutic drug (doxorubicin), gold nanorods and a tumour-specific aptamer MUC-1, to realize the effective circumvention of drug resistance. Doxorubicin (DOX) was loaded efficiently onto DNA origami through base pair intercalation and surface-modified gold nanorods (AuNRs) were assembled onto the DNA origami through DNA hybridization. Due to the active targeting effect of the assembled aptamers, the multifunctional nanostructures achieved increased cellular internalization of DOX and AuNRs. Upon near-infrared (NIR) laser irradiation, the P-glycoprotein (multidrug resistance pump) expression of multidrug resistant MCF-7 (MCF-7/ADR) cells was down-regulated, achieving the synergistically chemotherapeutic (DOX) and photothermal (AuNRs) effects.

  2. Graphene-Tapered ZnO Nanorods Array as a Flexible Antireflection Layer

    Taeseup Song

    2015-01-01

    Full Text Available Flexible solar cells have drawn a great deal of attention due to their various advantages including deformable and wearable characteristics. In the solar cells, the antireflection layer plays an important role in the improvement in the conversion efficiency by increasing the light transmission and suppressing the Fresnel refraction. For the successful implantation of the antireflection layer into the flexible solar cells, the flexible mechanical property of the antireflection layer is also necessary. However, the study on flexible antireflection layer for the flexible solar cells or optoelectronics is still lacking. In this study, we report the graphene-tapered ZnO nanorods array as a flexible antireflection layer for the application in flexible solar cells. Flexible two-dimensional graphene sheet and the tapered morphology of ZnO nanorods enable conformal coverage on the flexible substrate with curved surface and significant improvements in antireflection properties, respectively.

  3. Preference for Efficiency or Confusion? A Note on a Boundedly Rational Equilibrium Approach to Individual Contributions in a Public Good Game

    Luca Corazzini

    2015-01-01

    by error and noise in behavior. Results change when we consider a more general QRE specification with cross-subject heterogeneity in concerns for (group efficiency. In this case, we find that the majority of the subjects make contributions that are compatible with the hypothesis of preference for (group efficiency. A likelihood-ratio test confirms the superiority of the more general specification of the QRE model over alternative specifications.

  4. Electrical contacts to nanorod networks at different length scales: From macroscale ensembles to single nanorod chains

    Lavieville, Romain; Zhang, Yang; Di Fabrizio, Enzo M.; Krahne, Roman

    2013-01-01

    The nature of metal-semiconductor interfaces at the nanoscale is an important issue in micro- and nanoelectronic engineering. The study of charge transport through chains of CdSe semiconductor nanorods linked by Au particles represents an ideal model system for this matter, because the metal semiconductor interface is an intrinsic feature of the nanosystem. Here we show the controlled fabrication of all-inorganic hybrid metal-semiconductor networks with different size, in which the semiconductor nanorods are linked by Au domains at their tips. We demonstrate different approaches to selectively contact the networks and single nanorod chains with planar electrodes, and we investigate their charge transport at room temperature. © 2013 Elsevier B.V. All rights reserved.

  5. Electrical contacts to nanorod networks at different length scales: From macroscale ensembles to single nanorod chains

    Lavieville, Romain

    2013-11-01

    The nature of metal-semiconductor interfaces at the nanoscale is an important issue in micro- and nanoelectronic engineering. The study of charge transport through chains of CdSe semiconductor nanorods linked by Au particles represents an ideal model system for this matter, because the metal semiconductor interface is an intrinsic feature of the nanosystem. Here we show the controlled fabrication of all-inorganic hybrid metal-semiconductor networks with different size, in which the semiconductor nanorods are linked by Au domains at their tips. We demonstrate different approaches to selectively contact the networks and single nanorod chains with planar electrodes, and we investigate their charge transport at room temperature. © 2013 Elsevier B.V. All rights reserved.

  6. Gold nanorod vaccine for respiratory syncytial virus

    Stone, John W; Thornburg, Natalie J; Blum, David L; Kuhn, Sam J; Crowe Jr, James E; Wright, David W

    2013-01-01

    Respiratory syncytial virus (RSV) is a major cause of pneumonia and wheezing in infants and the elderly, but to date there is no licensed vaccine. We developed a gold nanorod construct that displayed the major protective antigen of the virus, the fusion protein (F). Nanorods conjugated to RSV F were formulated as a candidate vaccine preparation by covalent attachment of viral protein using a layer-by-layer approach. In vitro studies using ELISA, electron microscopy and circular dichroism revealed that conformation-dependent epitopes were maintained during conjugation, and transmission electron microscopy studies showed that a dispersed population of particles could be achieved. Human dendritic cells treated with the vaccine induced immune responses in primary human T cells. These results suggest that this vaccine approach may be a potent method for immunizing against viruses such as RSV with surface glycoproteins that are targets for the human immune response. (paper)

  7. Bismuth oxide nanorods based immunosensor for mycotoxin detection

    Solanki, Pratima R., E-mail: pratimarsolanki@gmail.com [DST Centre for Biomolecular Electronics, CSIR-National Physical Laboratory, K.S. Krishnan Marg, New Delhi (India); Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Singh, Jay [DST Centre for Biomolecular Electronics, CSIR-National Physical Laboratory, K.S. Krishnan Marg, New Delhi (India); Department of Applied Chemistry and Polymer Technology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042 (India); Rupavali, Bharti [DST Centre for Biomolecular Electronics, CSIR-National Physical Laboratory, K.S. Krishnan Marg, New Delhi (India); Tiwari, Sachchidanand [Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Malhotra, Bansi D., E-mail: bansi.malhotra@gmail.com [DST Centre for Biomolecular Electronics, CSIR-National Physical Laboratory, K.S. Krishnan Marg, New Delhi (India); Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042 (India)

    2017-01-01

    We report results of the studies relating to fabrication of an efficient immunosensor based on bismuth oxide nanorods (nBi{sub 2}O{sub 3}), electrophoretically deposited onto indium-tin-oxide (ITO) coated glass substrate. This immunosensor was fabricated by immobilization of anti-aflatoxin monoclonal antibodies (Ab-AFB1) and bovine serum albumin (BSA) for aflatoxin B1 detection. The structural and morphological studies of n-Bi{sub 2}O{sub 3} have been carried out by XRD, UV–vis spectrophotometer; SEM, AFM and FTIR. It was found that the nBi{sub 2}O{sub 3} provided improved sensing characteristics to the electrode interface in terms of electroactive surface area, diffusion coefficient, charge transfer rate constant and electron transfer kinetics. The results of electrochemical response studies of this BSA/Ab-AFB1/nBi{sub 2}O{sub 3}/ITO immunosensor revealed good linearity in the range of 1–70 ng dL{sup −1} with low detection limit of 8.715 ng/dL, improved sensitivity of 1.132 μA/(ng/dL cm{sup −2}), regression coefficient R{sup 2} of 0.918 and reproducibility of > 11 times. The association constant for the BSA/Ab-AFB1/nBi{sub 2}O{sub 3}/ITO immunosensor was determined as 7.318 ng/dL. - Highlights: • Use of Bismuth oxide nanorods for aflatoxin B1 detection. • It improved the electrochemical properties. • First report on nBi{sub 2}O{sub 3} for mycotoxin detection.

  8. Far-Infrared Absorption of PbSe Nanorods

    Hyun, Byung-Ryool; Bartnik, A. C.; Koh, Weon-kyu; Agladze, N. I.; Wrubel, J. P.; Sievers, A. J.; Murray, Christopher B.; Wise, Frank W.

    2011-01-01

    Measurements of the far-infrared absorption spectra of PbSe nanocrystals and nanorods are presented. As the aspect ratio of the nanorods increases, the Fröhlich sphere resonance splits into two peaks. We analyze this splitting with a classical

  9. Synthesis of carbon nanorods by reduction of carbon bisulfide

    Lou Zhengsong; He Minglong; Zhao Dejian; Li Zhongchun; Shang Tongming

    2010-01-01

    Research highlights: Our manuscript is a concise preliminary account of original and of significant research, which illuminates carbon nanorods and variously shaped Y-junction carbon nanorods are successfully fabricated on a large scale through a carbon bisulfide thermal reduction process. Various shaped Y-junction carbon nanorods can be used as studying the electronic and transport properties of the nano-meter carbon material. - Abstract: Carbon nanorods are synthesized at large scale by the reduction of carbon bisulfide at 600 o C. Moreover, novel Y-junction carbon nanorods are detected in the samples. The X-ray power diffraction pattern indicates that the products are hexagonal graphite. Scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy and N 2 physisorption studies show that carbon nanorods predominate in the product. Based on the supercritical carbon bisulfide system, the possible growth mechanism of the carbon nanorods was discussed. This method provides a simple and cheap route to large-scale synthesis of carbon nanorods.

  10. Templated synthesis of metal nanorods in silica nanotubes

    Yin, Yadong; Gao, Chuanbo

    2018-04-10

    A method of preparing a metal nanorod. The method includes seeding a metal nanoparticle within the lumen of a nanotube, and growing a metal nanorod from the seeded metal nanoparticle to form a metal nanorod-nanotube composite. In some cases, the nanotube includes metal binding ligands attached to the inner surface. Growing of the metal nanorod includes incubating the seeded nanotube in a solution that includes: a metal source for the metal in the metal nanorod, the metal source including an ion of the metal; a coordinating ligand that forms a stable complex with the metal ion; a reducing agent for reducing the metal ion, and a capping agent that stabilizes atomic monomers of the metal. Compositions derived from the method are also provided.

  11. Synthesis and thermoelectric properties of RuO2 nanorods

    Music, Denis; Basse, Felix H.-U.; Schneider, Jochen M.; Hassdorf, Ralf

    2010-01-01

    We have explored the effect of the O/Ru ratio on the morphology and the Seebeck coefficient of RuO 2 nanorods (space group P4 2 /mnm) synthesized by reactive sputtering. At an O/Ru ratio of 1.69, a faceted surface is observed, while nanorod formation occurs at O/Ru ratios of 2.03 and 2.24. Using classical molecular dynamics with the potential parameters derived in this work, we show that volatile species enable nanorod formation. Based on ab initio calculations, two effects of the nanorod formation on the Seebeck coefficient are observed: (i) increase due to additional states in the vicinity of the Fermi level and (ii) decrease due to oxygen point defects (volatile species). These two competing effects give rise to a moderate increase in the Seebeck coefficient upon nanorod formation.

  12. A simple wet chemical synthesis and characterization of hydroxyapatite nanorods

    Liu Yingkai; Hou Dedong; Wang Guanghou

    2004-01-01

    Calcium hydroxyapatite (Ca 5 (PO 4 ) 3 (OH):HAP) nanorods have been synthesized successfully via wet chemical technique at low temperature in the presence of suitable surfactant. The as-made nanorods have a diameter of 50-80 nm and a length of 0.5-1.2 μm. The microstructures and composition are characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectrometer (FT-IR). The formation mechanism of HAP nanorod is discussed in detail. It has been found that nanorods are pure, there is no HAP carbonated HAP. The growth mechanism of HAP nanorods could be explained by a soft template

  13. Nanoscale Rheology and Anisotropic Diffusion Using Single Gold Nanorod Probes

    Molaei, Mehdi; Atefi, Ehsan; Crocker, John C.

    2018-03-01

    The complex rotational and translational Brownian motion of anisotropic particles depends on their shape and the viscoelasticity of their surroundings. Because of their strong optical scattering and chemical versatility, gold nanorods would seem to provide the ultimate probes of rheology at the nanoscale, but the suitably accurate orientational tracking required to compute rheology has not been demonstrated. Here we image single gold nanorods with a laser-illuminated dark-field microscope and use optical polarization to determine their three-dimensional orientation to better than one degree. We convert the rotational diffusion of single nanorods in viscoelastic polyethylene glycol solutions to rheology and obtain excellent agreement with bulk measurements. Extensions of earlier models of anisotropic translational diffusion to three dimensions and viscoelastic fluids give excellent agreement with the observed motion of single nanorods. We find that nanorod tracking provides a uniquely capable approach to microrheology and provides a powerful tool for probing nanoscale dynamics and structure in a range of soft materials.

  14. Facile synthesis of CdS@TiO2 core–shell nanorods with controllable shell thickness and enhanced photocatalytic activity under visible light irradiation

    Dong, Wenhao; Pan, Feng; Xu, Leilei; Zheng, Minrui; Sow, Chorng Haur; Wu, Kai; Xu, Guo Qin

    2015-01-01

    Graphical abstract: - Highlights: • CdS nanorods were coated with amorphous TiO 2 shells under a mild condition. • The TiO 2 shell thickness can be controlled from 3.5 to 40 nm. • CdS@TiO 2 nanorods exhibit enhanced photocatalytic activities under visible light. • Efficient charge carriers separation leads to the improved photocatalytic activity. - Abstract: Amorphous TiO 2 layers with a controllable thickness from 3.5 to 40 nm were coated on the one-dimensional CdS nanorods surface under mild conditions. Compared to the bare CdS nanorods, the as-prepared CdS@TiO 2 nanorods exhibit enhanced photocatalytic activities for phenol photodecomposition under visible light irradiation. The improved photoactivity is ascribed to the efficient separation of photogenerated electron and hole charge carriers between CdS cores and TiO 2 shells. This study promises a simple approach to fabricating CdS@TiO 2 core–shell structure nanocomposites, and can be applied for other semiconductor cores with TiO 2 shells

  15. Zinc oxide nanorod mediated visible light photoinactivation of model microbes in water

    Sapkota, Ajaya; Anceno, Alfredo J; Dutta, Joydeep [Center of Excellence in Nanotechnology, Asian Institute of Technology, Klong Luang, Pathumthani 12120 (Thailand); Baruah, Sunandan; Shipin, Oleg V, E-mail: alfredo.anceno@cemagref.fr, E-mail: joy@ait.ac.th [Environmental Engineering and Management, Asian Institute of Technology, Klong Luang, Pathumthani 12120 (Thailand)

    2011-05-27

    The inactivation of model microbes in aqueous matrix by visible light photocatalysis as mediated by ZnO nanorods was investigated. ZnO nanorods were grown on glass substrate following a hydrothermal route and employed in the inactivation of gram-negative Escherichia coli and gram-positive Bacillus subtilis in MilliQ water. The concentration of Zn{sup 2+} ions in the aqueous matrix, bacterial cell membrane damage, and DNA degradation at post-exposure were also studied. The inactivation efficiencies for both organisms under light conditions were about two times higher than under dark conditions across the cell concentrations assayed. Anomalies in supernatant Zn{sup 2+} concentration were observed under both conditions as compared to control treatments, while cell membrane damage and DNA degradation were observed only under light conditions. Inactivation under dark conditions was hence attributed to the bactericidal effect of Zn{sup 2+} ions, while inactivation under light conditions was due to the combined effects of Zn{sup 2+} ions and photocatalytically mediated electron injection. The reduction of pathogenic bacterial densities by the photocatalytically active ZnO nanorods in the presence of visible light implies potential ex situ application in water decontamination at ambient conditions under sunlight.

  16. Selective Synthesis of Mesoporous and Nanorod CeVO4 without Template

    Zhu Ling; Li Qin; Li Jiayan; Liu Xiangdong; Meng Jian; Cao Xueqiang

    2007-01-01

    A simple and efficient method has been established for the selective synthesis of mesoporous and nanorod CeVO 4 with different precursors by sonochemical method. CeVO 4 nanorod can be simply synthesized by ultrasound irradiation of Ce(NO 3 ) 3 and NH 4 VO 3 in aqueous solution without any surfactant or template. While mesoporous CeVO 4 with high specific surface area can be prepared with Ce(NO 3 ) 3 , V 2 O 5 and NaOH in the same way. Mesoporous CeVO 4 has a specific surface area of 122 m 2 g -1 and an average pore size of 5.2 nm; CeVO 4 nanorods have a diameter of about 5 nm, and a length of 100-150 nm. The ultrasound irradiation and ammonia in the reactive solution are two key factors in the formation of such rod-like products. X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG) and differential thermal analyses (DTA), UV/vis absorption spectroscopy and Brunauer-Emmett-Teller (BET) were applied for characterization of the as-prepared products

  17. Control of size and aspect ratio in hydroquinone-based synthesis of gold nanorods

    Morasso, Carlo, E-mail: cmorasso@dongnocchi.it; Picciolini, Silvia; Schiumarini, Domitilla [Fondazione Don Carlo Gnocchi ONLUS, Laboratory of Nanomedicine and Clinical Biophotonics (LABION) (Italy); Mehn, Dora; Ojea-Jiménez, Isaac [European Commission Joint Research Centre, Institute for Health and Consumer Protection (IHCP) (Italy); Zanchetta, Giuliano [Universitá degli Studi di Milano, Dipartimento di Biotecnologie Mediche e Medicina Traslazionale (Italy); Vanna, Renzo; Bedoni, Marzia [Fondazione Don Carlo Gnocchi ONLUS, Laboratory of Nanomedicine and Clinical Biophotonics (LABION) (Italy); Prosperi, Davide [Università degli Studi di Milano Bicocca, NanoBioLab, Dipartimento di Biotecnologie e Bioscienze (Italy); Gramatica, Furio [Fondazione Don Carlo Gnocchi ONLUS, Laboratory of Nanomedicine and Clinical Biophotonics (LABION) (Italy)

    2015-08-15

    In this article, we describe how it is possible to tune the size and the aspect ratio of gold nanorods obtained using a highly efficient protocol based on the use of hydroquinone as a reducing agent by varying the amounts of CTAB and silver ions present in the “seed-growth” solution. Our approach not only allows us to prepare nanorods with a four times increased Au{sup 3+} reduction yield, when compared with the commonly used protocol based on ascorbic acid, but also allows a remarkable reduction of 50–60 % of the amount of CTAB needed. In fact, according to our findings, the concentration of CTAB present in the seed-growth solution do not linearly influence the final aspect ratio of the obtained nanorods, and an optimal concentration range between 30 and 50 mM has been identified as the one that is able to generate particles with more elongated shapes. On the optimized protocol, the effect of the concentration of Ag{sup +} ions in the seed-growth solution and the stability of the obtained particles has also been investigated.

  18. Control of size and aspect ratio in hydroquinone-based synthesis of gold nanorods

    Morasso, Carlo; Picciolini, Silvia; Schiumarini, Domitilla; Mehn, Dora; Ojea-Jiménez, Isaac; Zanchetta, Giuliano; Vanna, Renzo; Bedoni, Marzia; Prosperi, Davide; Gramatica, Furio

    2015-01-01

    In this article, we describe how it is possible to tune the size and the aspect ratio of gold nanorods obtained using a highly efficient protocol based on the use of hydroquinone as a reducing agent by varying the amounts of CTAB and silver ions present in the “seed-growth” solution. Our approach not only allows us to prepare nanorods with a four times increased Au 3+ reduction yield, when compared with the commonly used protocol based on ascorbic acid, but also allows a remarkable reduction of 50–60 % of the amount of CTAB needed. In fact, according to our findings, the concentration of CTAB present in the seed-growth solution do not linearly influence the final aspect ratio of the obtained nanorods, and an optimal concentration range between 30 and 50 mM has been identified as the one that is able to generate particles with more elongated shapes. On the optimized protocol, the effect of the concentration of Ag + ions in the seed-growth solution and the stability of the obtained particles has also been investigated

  19. Nanorod niobium oxide as powerful catalysts for an all vanadium redox flow battery.

    Li, Bin; Gu, Meng; Nie, Zimin; Wei, Xiaoliang; Wang, Chongmin; Sprenkle, Vincent; Wang, Wei

    2014-01-08

    A powerful low-cost electrocatalyst, nanorod Nb2O5, is synthesized using the hydrothermal method with monoclinic phases and simultaneously deposited on the surface of a graphite felt (GF) electrode in an all vanadium flow battery (VRB). Cyclic voltammetry (CV) study confirmed that Nb2O5 has catalytic effects toward redox couples of V(II)/V(III) at the negative side and V(IV)/V(V) at the positive side to facilitate the electrochemical kinetics of the vanadium redox reactions. Because of poor conductivity of Nb2O5, the performance of the Nb2O5 loaded electrodes is strongly dependent on the nanosize and uniform distribution of catalysts on GF surfaces. Accordingly, an optimal amount of W-doped Nb2O5 nanorods with minimum agglomeration and improved distribution on GF surfaces are established by adding water-soluble compounds containing tungsten (W) into the precursor solutions. The corresponding energy efficiency is enhanced by ∼10.7% at high current density (150 mA·cm(-2)) as compared with one without catalysts. Flow battery cyclic performance also demonstrates the excellent stability of the as prepared Nb2O5 catalyst enhanced electrode. These results suggest that Nb2O5-based nanorods, replacing expensive noble metals, uniformly decorating GFs holds great promise as high-performance electrodes for VRB applications.

  20. Contribution of Root Traits to Phosphorus Acqusition Efficiency by Maize Landraces in Acid Soils of the Highlands in Central Mexico

    Bayuelo-Jimenez, J. S.; Hernandez-Bravo, N.; Magdaleno-Armas, M. L.; Perez-Decelis, V. A. [Instituto Nacional de Investigaciones Agropecuarias y Forestales, Universidad Michoacana de San Nicolas de Hidalgo, Tarimbaro, Michoacan (Mexico); Gallardo-Valdez, M. [Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias,. Campo Experimental Uruapan (Mexico); Ochoa, I. [Unipalma S.A. Bogota D.C. (Colombia); Paredes-Gutierrez, L. C. [Centro Nuclear Dr. Nabor Carrillo Flores, Instituto Nacional de Investigaciones Nucleares, Municipio de Ocoyoacac, Salazar (Mexico); Lynch, J. P. [Department of Horticulture, Pennsylvania State University, University Park, PA (United States)

    2013-11-15

    Plants have a wide range of mechanisms and morphological features that increase availability and acquisition of orthophosphate from soil. Root growth, root branching, and root hair morphology are important for the efficient acquisition of phosphorus (P). The series of studies reported here was based on the hypothesis that Mexican maize landraces, which have developed mostly in environments with low P availability and have a well-developed root system, could be a source of variation for the improvement of phosphorus acquisition. Several studies were conducted to evaluate genotypic variation in both root (root architecture and morphology, including root hairs) and plant growth traits associated with P acquisition efficiency (PAE) and/or P utilization efficiency (PUE) of maize landraces in a P-deficient Andisol in the Central Mexican Highlands, and to identify genotypic differences, among both efficient and inefficient in P acquisition and responsive and non-responsive maize landraces to applied P. The results showed that accessions differed greatly in plant growth, grain yield, root morphology, total uptake of P, PAE, PUE, and P efficiency defined as growth with suboptimal P availability. Phosphorus-efficient accessions had not only greater biomass per unit of absorbed P, but also larger root systems, greater P uptake per unit root weight, more nodal roots, nodal root laterals, and greater root hair density of nodal root main axes and first-order laterals than did Pinefficient accessions under P deficiency. Root biomass allocation, as quantified by the allometric partitioning coefficient (K) was not altered by P availability in the efficient accessions, but inefficient accessions had less biomass partitioning to roots (i.e. a lower K) under low P conditions. Accessions with enhanced nodal rooting and laterals had greater P uptake and growth under low P. Dense root hairs on nodal root main axes and first-order laterals conferred a marked benefit under low P, as

  1. Contributing to a green energy economy? A macroeconomic analysis of an energy efficiency program operated by a Swiss utility

    Yushchenko, Alisa; Patel, Martin Kumar

    2016-01-01

    Highlights: • Our input–output model allows estimating impacts of energy efficiency programs on GDP and employment in Switzerland. • We provide with a deeper insight into modeling of income impacts of energy savings with regard to input–output method. • Geneva case study demonstrates that energy efficiency programs can have positive macroeconomic impacts in Switzerland. • Our results help to understand how to enhance positive macroeconomic impacts of energy efficiency programs. • We provide policy recommendations for further development of energy efficiency programs. - Abstract: In order to enhance energy efficiency as a pillar of transition to a green energy economy it is important to understand whether and under which conditions energy efficiency programs could have positive economic and social impacts. There are a growing number of studies on macroeconomic impacts of energy efficiency programs for various countries and regions. However, in Switzerland only few evaluations have been performed. The present study evaluates the impacts on GDP and employment of Geneva’s energy efficiency program portfolio éco21 which is operated by the local utility. Two programs aiming for electricity savings in the residential sector are analyzed: Eco-sociales targets social housing and Communs d’immeubles focuses on common spaces in buildings. An input–output model is developed, based on the Swiss input–output table, program administrator data, Swiss, and European statistics. Both impacts of initial expenditure and energy cost savings are evaluated. We estimate and compare the impacts of the two programs and discuss factors that cause differences. Our results show that energy efficiency programs can have positive impacts on GDP and employment. According to our estimates, each Swiss Franc (CHF) spent within the energy efficiency program creates approximately 0.2 CHF of additional GDP compared to the reference case scenario. Net impacts on employment are

  2. Effect of Temperature and Growth Time on Vertically Aligned ZnO Nanorods by Simplified Hydrothermal Technique for Photoelectrochemical Cells.

    Mohd Fudzi, Laimy; Zainal, Zulkarnain; Lim, Hong Ngee; Chang, Sook-Keng; Holi, Araa Mebdir; Sarif Mohd Ali, Mahanim

    2018-04-29

    Despite its large band gap, ZnO has wide applicability in many fields ranging from gas sensors to solar cells. ZnO was chosen over other materials because of its large exciton binding energy (60 meV) and its stability to high-energy radiation. In this study, ZnO nanorods were deposited on ITO glass via a simple dip coating followed by a hydrothermal growth. The morphological, structural and compositional characteristics of the prepared films were analyzed using X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), and ultraviolet-visible spectroscopy (UV-Vis). Photoelectrochemical conversion efficiencies were evaluated via photocurrent measurements under calibrated halogen lamp illumination. Thin film prepared at 120 °C for 4 h of hydrothermal treatment possessed a hexagonal wurtzite structure with the crystallite size of 19.2 nm. The average diameter of the ZnO nanorods was 37.7 nm and the thickness was found to be 2680.2 nm. According to FESEM images, as the hydrothermal growth temperature increases, the nanorod diameter become smaller. Moreover, the thickness of the nanorods increase with the growth time. Therefore, the sample prepared at 120 °C for 4 h displayed an impressive photoresponse by achieving high current density of 0.1944 mA/cm².

  3. Carbon-Coated Perovskite BaMnO3 Porous Nanorods with Enhanced Electrocatalytic Perporites for Oxygen Reduction and Oxygen Evolution

    Xu, Yujiao; Tsou, Alvin; Fu, Yue; Wang, Jin; Tian, Jing-Hua; Yang, Ruizhi

    2015-01-01

    A thin carbon layer has been introduced to coat on the perovskite BaMnO 3 nanorods by a facile method, which exhibit significantly enhanced electrocatalytic activity for both the ORR and OER with excellent stability. - Highlights: • A non-rare-earth element based perovskite BaMnO 3 nanorods as an active electrocatalyst for the ORR and OER have been prepared and investigated for the first time. • A thin carbon-coating layer with thickness of approximately 10 nm has been successfully introduced to enhance the electrical conductivity and the electrocatalytic activities of the bare perovskite for both ORR and OER. • The stabilities of bare BaMnO 3 nanorods for both ORR and OER have also been improved dramatically with the help of carbon coating, especially for the OER process. - Abstract: Highly efficient, low-cost catalysts, especially with bifunctional electrocatalytic capabilities for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are vital for the wide commercialization of fuel cells and metal-air batteries. In this study, BaMnO 3 - a non-rare-earth element based perovskite nanorods have been prepared and investigated for the first time, and a thin carbon-coating with a thickness of approximately 10 nm has been successfully introduced to enhance the electrical conductivity of the bare perovskite. Electrochemical tests reveal that bare BaMnO 3 nanorods exhibit very good catalytic activity. More interestingly, a remarkably enhanced ORR activity for the perovskite BaMnO 3 nanorods was observed after coating with a thin layer of carbon, which dominated with a direct four-electron pathway. Meanwhile, the OER process has also been enhanced extraordinarily with the carbon-coating, reaching a maximum of 14.8 mA cm −2 at 1.0 V (vs. Ag/AgCl), which is far superior to both the bare BaMnO 3 nanorods and commercial Pt/C (20 wt%) catalysts. Furthermore, the stabilities of bare BaMnO 3 nanorods for both ORR and OER have also been improved

  4. Silane decorated metallic nanorods for hydrophobic applications

    Kannarpady, Ganesh K.; Sharma, Rajesh; Liu Bo; Trigwell, Steve; Ryerson, Charles; Biris, Alexandru S.

    2010-01-01

    A novel technique to modify a metallic surface for anti-icing applications is presented. An oblique angle deposition (OAD) technique has been used to fabricate metallic nanorods of Aluminum and Tungsten on a glass substrate. A conformal coating of a silane has been applied using a molecular vapor deposition technique. The resulting surface has shown a static contact angle of 134 deg. with the water droplet. SEM, AFM and XPS have been used to study the surface modification. This is a highly promising approach for anti-icing applications due to its scalability at a very low cost.

  5. Fabricating hydroxyapatite nanorods using a biomacromolecule template

    Zhu Aiping; Lu Yan; Si Yunfeng; Dai Sheng

    2011-01-01

    Rod-like hydroxyapatite (HAp) nanoparticles with various aspect ratios are synthesized by means of low-temperature hydrothermal method in the presence of a N-[(2-hydroxy-3-trimethylammonium) propyl]chitosan chloride (HTCC) template. The synthesized HAps were examined by X-ray diffraction (XRD), Fourier transform infrared spectrophotometer (FTIR) and transmission electron microscopy (TEM) techniques. The results reveal that HAps are rod-like monocrystals, where the size and morphology can be tailored by varying synthesis conditions, such as pH, hydrothermal synthesis temperature and the ratio of PO 4 3- to the quaternary ammonium in HTCC. The mechanism of HTCC template on HAp nanorod preparation is analyzed.

  6. Frabicating hydroxyapatite nanorods using a biomacromolecule template

    Zhu, Aiping; Lu, Yan; Si, Yunfeng; Dai, Sheng

    2011-02-01

    Rod-like hydroxyapatite (HAp) nanoparticles with various aspect ratios are synthesized by means of low-temperature hydrothermal method in the presence of a N-[(2-hydroxy-3-trimethylammonium) propyl]chitosan chloride (HTCC) template. The synthesized HAps were examined by X-ray diffraction (XRD), Fourier transform infrared spectrophotometer (FTIR) and transmission electron microscopy (TEM) techniques. The results reveal that HAps are rod-like monocrystals, where the size and morphology can be tailored by varying synthesis conditions, such as pH, hydrothermal synthesis temperature and the ratio of PO43- to the quaternary ammonium in HTCC. The mechanism of HTCC template on HAp nanorod preparation is analyzed.

  7. Porphyrin coordination polymer nanospheres and nanorods

    Wang, Zhongchun; Shelnutt, John A.; Medforth, Craig J.

    2012-12-04

    A porphyrin coordination polymer nanostructure comprising a network of pyridyl porphyrin molecules and coordinating metal ions coordinatively bound through the pyridyl groups. In some embodiments, the porphyrins are metalloporphyrins. A variety of nanostructures are formed by the network polymer, including nanospheres, polygonal nanostructures, nanorods, and nanofibers, depending on a variety of factors including coordination metal ion, porphyrin type, metal of the metalloporphyrin, and degree of agitation during nanostructure formation. Reduction of coordinating metal ions may be used to form metal nanoparticles on the coordination polymer nanostructure.

  8. Efficiency of the emission trading. A contribution to the climate protection law; Effizienz im Emissionshandel. Ein Beitrag zum Klimaschutzrecht

    Frenz, Walter [RWTH Aachen Univ. (Germany). Lehr- und Forschungsgebiet Berg-, Umwelt- und Europarecht; Wimmers, Kristina [RWTH Aachen Univ. (Germany)

    2014-07-01

    The contribution discusses the following topics: Inclusion of additional sectors into the emission trading: road traffic and sea traffic, the stepwise realization and difficulties; the failed inclusion of air traffic, rigid penalties in case of violation of the fee delivery, thread for the complete mechanism, over-compliance in Germany and international perspectives.

  9. Efficiency enhancement in a single emission layer yellow organic light emitting device: Contribution of CIS/ZnS quantum dot

    Demir, Nuriye; Oner, Ilker; Varlikli, Canan, E-mail: canan.varlikli@ege.edu.tr; Ozsoy, Cihan; Zafer, Ceylan

    2015-08-31

    Electroluminescence (EL) efficiency from a single emission layer solution processed yellow emitting polymer, i.e. poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,10,3}-thiadiazole)] end-capped with dimethylphenyl (ADS233YE), is firstly enhanced by the optimization of stock polymer concentrations and the coating rates, and then with the addition of copper indium disulfide/zinc sulfide (CIS/ZnS) core/shell quantum dots (QDs). Using these bare core/shell QDs as the active layer in the studied device gave no EL at all. However, yellow EL with the maximum brightness of 56834 cd/m{sup 2}, maximum current efficiency of 4.7 cd/A and maximum power efficiency of 2.3 lm/W is obtained from the device structure of indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/ADS233YE:0.4 wt.% CIS/ZnS QD/Ca/Al those of which correspond to approximately 4 and 2 folds of enhancements in the brightness and luminous and power efficiency values, respectively, compared to that of the device without CIS/ZnS. - Highlights: • Copper indium disulfide/zinc sulfide (CIS/ZnS) particles are synthesized. • Polymer light emitting diode performance of a yellow emitting polymer is enhanced. • The presence of CIS/ZnS in active layer enhanced the power efficiency two folds. • Optimum concentration of CIS/ZnS in polymer is 0.4 wt.%.

  10. Efficiency enhancement in a single emission layer yellow organic light emitting device: Contribution of CIS/ZnS quantum dot

    Demir, Nuriye; Oner, Ilker; Varlikli, Canan; Ozsoy, Cihan; Zafer, Ceylan

    2015-01-01

    Electroluminescence (EL) efficiency from a single emission layer solution processed yellow emitting polymer, i.e. poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,10,3}-thiadiazole)] end-capped with dimethylphenyl (ADS233YE), is firstly enhanced by the optimization of stock polymer concentrations and the coating rates, and then with the addition of copper indium disulfide/zinc sulfide (CIS/ZnS) core/shell quantum dots (QDs). Using these bare core/shell QDs as the active layer in the studied device gave no EL at all. However, yellow EL with the maximum brightness of 56834 cd/m 2 , maximum current efficiency of 4.7 cd/A and maximum power efficiency of 2.3 lm/W is obtained from the device structure of indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/ADS233YE:0.4 wt.% CIS/ZnS QD/Ca/Al those of which correspond to approximately 4 and 2 folds of enhancements in the brightness and luminous and power efficiency values, respectively, compared to that of the device without CIS/ZnS. - Highlights: • Copper indium disulfide/zinc sulfide (CIS/ZnS) particles are synthesized. • Polymer light emitting diode performance of a yellow emitting polymer is enhanced. • The presence of CIS/ZnS in active layer enhanced the power efficiency two folds. • Optimum concentration of CIS/ZnS in polymer is 0.4 wt.%

  11. Improving energy efficiency of dedicated cooling system and its contribution towards meeting an energy-optimized data center

    Cho, Jinkyun; Kim, Yundeok

    2016-01-01

    Highlights: • Energy-optimized data center’s cooling solutions were derived for four different climate zones. • We studied practical technologies of green data center that greatly improved energy efficiency. • We identified the relationship between mutually dependent factors in datacenter cooling systems. • We evaluated the effect of the dedicated cooling system applications. • Power Usage Effectiveness (PUE) was computed with energy simulation for data centers. - Abstract: Data centers are approximately 50 times more energy-intensive than general buildings. The rapidly increasing energy demand for data center operation has motivated efforts to better understand data center electricity use and to identify strategies that reduce the environmental impact. This research is presented analytical approach to the energy efficiency optimization of high density data center, in a synergy with relevant performance analysis of corresponding case study. This paper builds on data center energy modeling efforts by characterizing climate and cooling system differences among data centers and then evaluating their consequences for building energy use. Representative climate conditions for four regions are applied to data center energy models for several different prototypical cooling types. This includes cooling system, supplemental cooling solutions, design conditions and controlling the environment of ICT equipment were generally used for each climate zone, how these affect energy efficiency, and how the prioritization of system selection is derived. Based on the climate classification and the required operating environmental conditions for data centers suggested by the ASHRAE TC 9.9, a dedicated data center energy evaluation tool was taken to examine the potential energy savings of the cooling technology. Incorporating economizer use into the cooling systems would increase the variation in energy efficiency among geographic regions, indicating that as data centers

  12. In vitro toxicity studies of polymer-coated gold nanorods

    Rayavarapu, Raja G; Petersen, Wilma; Manohar, Srirang; Van Leeuwen, Ton G [Biomedical Photonic Imaging Group, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, University of Twente, PO Box 217, 7500AE Enschede (Netherlands); Hartsuiker, Liesbeth; Otto, Cees [Medical Cell Biophysics, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, University of Twente, PO Box 217, 7500AE Enschede (Netherlands); Chin, Patrick; Van Leeuwen, Fijs W B [Division of Diagnostic Oncology, Netherlands Cancer Institute, 1066 CX Amsterdam (Netherlands); Janssen, Hans, E-mail: S.Manohar@utwente.nl [Division of Cell Biology, The Netherlands Cancer Institute, 1066 CX Amsterdam (Netherlands)

    2010-04-09

    We evaluated cellular responses to polymer-treated gold nanorods, which were synthesized using the standard wet-chemistry method that utilizes hexadecyltrimethylammonium bromide (CTAB). The nanorod dispersions were coated with either polystyrene sulfonate (PSS) or polyethylene glycol (PEG). Two sizes of nanorods were tested, with optical responses peaking at 628 and 773 nm. The cells were from mammary adenocarcinoma (SKBR3), Chinese Hamster Ovary (CHO), mouse myoblast (C2C12) and Human Leukemia (HL60) cell lines. Their mitochondrial function following exposure to the nanorods were assessed using the MTS assay. We found PEGylated particles to have superior biocompatibility compared with PSS-coated nanorods, which showed substantial cytotoxicity. Electron microscopy showed no cellular uptake of PEGylated particles compared with their PSS counterparts. PEGylated gold nanorods also exhibited better dispersion stability in the presence of cell growth medium; PSS-coated rods tended to flocculate or cluster. In the case of the PSS particles, toxicity correlated with surface area across the two sizes of nanorods studied.

  13. A simple semi-empirical way of accounting for the contribution of pair production process to the efficiency of Ge detectors

    Sudarshan, M.; Singh, R.

    1991-01-01

    By considering the data for a 38cm 3 Ge(Li) detector from E γ = 319.80 to 2598.80 keV, and for a 68 cm 3 HPGe detector from E γ = 223.430 to 3253.610 keV, it has been demonstrated that the contribution of the pair production process to the full energy peak efficiency (FEPE) of germanium detectors can be quite adequately accounted for in a semi-empirical way. (author)

  14. Charge separation in branched TiO_2 nanorod array homojunction aroused by quantum effect for enhanced photocatalytic decomposition of gaseous benzene

    Wang, Xiaoxia; Ni, Qian; Zeng, Dawen; Liao, Guanglan; Xie, Changsheng

    2016-01-01

    Highlights: • Charge separation in homojunction based on the broadened band gap by quantum effect. • Absolute charge separation by the passivation effect of TiO_2 nanorod. • Long-distance electron transfer behavior in photocatalysis. • Roughed surface for enhanced light harvesting by light trapping effect. - Abstract: As known, the electron transfer behavior in photocatalysis is short-distance transportation, which leads the photo-induced electrons and holes to be localized. The temporarily separated electrons and holes will recombine with each other in the localized region. In this paper, we successfully achieved electron transfer in a homojunction of branched rutile TiO_2 nanorod @nanoparticle core-shell architecture by quantum confinement effect aroused by the nanoparticle, which is proved by the blue-shifting in UV–vis absorption spectrum of the homojunction. Meanwhile, an absolute charge separation is also achieved by the long-distance electron transfer along the single-crystalline rutile TiO_2 nanorod as uninterrupted high-speed electron transfer channel to FTO substrates. Based on the effective charge separation, the photocatalytic decomposition of gaseous benzene by the homojunction is significantly enhanced, yielding 10 times CO_2 than that of the nanorod array. This homojunction interfacial charge separation, aroused by quantum effect, through long-distance transfer along the single-crystalline nanorod gives us inspiration to achieve efficient charge separation with defect-less interfaces, which might can be utilized for real-time environmental abatement and energy generation simultaneously.

  15. Rapid thermal melted TiO2 nano-particles into ZnO nano-rod and its application for dye sensitized solar cells

    Chao, Ching-Hsun; Chang, Chi-Lung; Chan, Chien-Hung; Lien, Shui-Yang; Weng, Ko-Wei; Yao, Kuo-Shan

    2010-01-01

    TiO 2 nano-particles with an anchored ZnO nano-rod structure were synthesized using the hydrothermal method to grow ZnO nano-rods and coated TiO 2 nano-particles on ZnO nano-rods using the rapid thermal annealing method on ITO conducting glass pre-coated with nano porous TiO 2 film. The XRD study showed that there was little difference in crystal composition for various types of TiO 2 nano-particles anchored to ZnO nano-rods. The as-prepared architecture was characterized using field-emission scanning electron microscopy (FE-SEM). Films with TiO 2 nano-particles anchored to ZnO nano-rods were used as electrode materials to fabricate dye sensitized solar cells (DSSCs). The best solar energy conversion efficiency of 2.397% was obtained by modified electrode material, under AM 1.5 illumination, achieved up to J sc = 15.382 mA/cm 2 , V oc = 0.479 V and fill factor = 32.8%.

  16. Effect of TiO{sub 2} thickness on nanocomposited aligned ZnO nanorod/TiO{sub 2} for dye-sensitized solar cells

    Saurdi, I., E-mail: saurdy788@gmail.com; Ishak, A. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM),40450 Shah Alam, Selangor (Malaysia); UiTM Sarawak Kampus Kota Samarahan Jalan Meranek, Sarawak (Malaysia); Shafura, A. K.; Azhar, N. E. A.; Mamat, M. H. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM),40450 Shah Alam, Selangor (Malaysia); Malek, M. F.; Rusop, M. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM),40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), (Centre for Nano-Science and Nano-Technology), Institute of Science - IOS, Universiti Teknologi MARA - UiTM, 40450 Shah Alam, Selangor (Malaysia); Alrokayan, A. H. Salman; Khan, Haseeb A. [Department of Biochemistry, College of Science, Bldg. 5, King Saud University (KSU) P.O: 2455 Riyadh 1145 (Saudi Arabia)

    2016-07-06

    The TiO{sub 2} films were deposited on glass substrate at different thicknesses with different deposition frequencies (1, 2, 3 and 4 times) using spin coating technique and their structural properties were investigated. Subsequently, the nanocomposited aligned ZnO nanorods and TiO{sub 2} were formed by deposited the TiO{sub 2} on top of aligned ZnO Nanorod on ITO-coated glass at different thicknesses using the same method of TiO{sub 2} deposited on glass substrate. The nanocomposited aligned ZnO nanorod/TiO{sub 2} were coated with different thicknesses of 900µm, 1815µm, 2710µm, 3620µm and ZnO without TiO{sub 2}. The dye-sensitized solar cells were fabricated from the nanocomposited aligned ZnO nanorod/TiO{sub 2} with thickness of 900µm, 1815µm, 2710µm and 3620µm and ZnO without TiO{sub 2} and their photovoltaic properties of the DSSCs were investigated. From the solar simulator measurement the solar energy conversion efficiency (η) of 2.543% under AM 1.5 was obtained for the ZnO nanorod/TiO{sub 2} photoanode-2710µm Dye-Sensitized solar cell.

  17. Batteries for efficient energy extraction from a water salinity difference.

    La Mantia, Fabio; Pasta, Mauro; Deshazer, Heather D; Logan, Bruce E; Cui, Yi

    2011-04-13

    The salinity difference between seawater and river water is a renewable source of enormous entropic energy, but extracting it efficiently as a form of useful energy remains a challenge. Here we demonstrate a device called "mixing entropy battery", which can extract and store it as useful electrochemical energy. The battery, containing a Na(2-x)Mn(5)O(10) nanorod electrode, was shown to extract energy from real seawater and river water and can be applied to a variety of salt waters. We demonstrated energy extraction efficiencies of up to 74%. Considering the flow rate of river water into oceans as the limiting factor, the renewable energy production could potentially reach 2 TW, or ∼13% of the current world energy consumption. The mixing entropy battery is simple to fabricate and could contribute significantly to renewable energy in the future.

  18. Batteries for Efficient Energy Extraction from a Water Salinity Difference

    La Mantia, Fabio

    2011-04-13

    The salinity difference between seawater and river water is a renewable source of enormous entropic energy, but extracting it efficiently as a form of useful energy remains a challenge. Here we demonstrate a device called "mixing entropy battery", which can extract and store it as useful electrochemical energy. The battery, containing a Na2-xMn 5O10 nanorod electrode, was shown to extract energy from real seawater and river water and can be applied to a variety of salt waters. We demonstrated energy extraction efficiencies of up to 74%. Considering the flow rate of river water into oceans as the limiting factor, the renewable energy production could potentially reach 2 TW, or ∼13% of the current world energy consumption. The mixing entropy battery is simple to fabricate and could contribute significantly to renewable energy in the future. © 2011 American Chemical Society.

  19. Lack of Energy Efficiency Legislation in the Malaysian Building Sector Contributes to Malaysia’s Growing GHG Emissions

    Zaid Suzaini M.

    2014-01-01

    Full Text Available Malaysia’s carbon emissions grew by +235.6% from 1990 to 2005, largely due to an increase in national energy demand of 210.7% from 1990 to 2004. This unparalleled carbon emission growth, along with business-as-usual (BAU practices will put Malaysia at high risk for carbon lock-in and a very unsustainable path of development. Malaysia clearly needs to make significant and urgent changes in its policy, economy, industries and lifestyle in order to reduce its climate change impacts. In 2010 Malaysia announced a voluntary commitment to reduce 40% of its greenhouse gases (GHG emissions by 2020 (from 1990 levels. Without emissions mitigation and conservation policies, Malaysia is unlikely to meet its emissions reduction targets. Presently, Malaysia has no energy efficiency legislation in its growing building sector. This paper reviews existing building policies and energy efficiency measures in Malaysia and highlights the need to implement mandatory energy efficiency building codes in reducing the sector’s impact on climate change.

  20. Influence of vibronic contribution on light harvesting efficiency of NKX-2587 derivatives with oligothiophene as π-conjugated linker

    Yang, Pan; Zhang, Yang; Li, Ming; Shen, Wei; He, Rongxing

    2018-01-01

    Based on the NKX-2587 molecule we designed ten sensitizers with 1-10 thiophene moieties to investigate how the number of thiophene unit in the spacer influences the absorption spectra of sensitizer in dye sensitized solar cells (DSSCs). The parameters of short-circuit current density (Jsc), open circuit voltage (Voc), the light harvesting efficiency (LHE), injection driving force (Δ Ginject), and transferred electron number (nc), were calculated and discussed in detail. Results indicated that the increasing of thiophene units makes for the enhancement of oscillator strengths (f), although the red shift of vertical electronic absorption spectra is small. For the designed sensitizers with 1-5 thiophene units, their ΔGinject and nc raise gradually with the increasing of thiophene number. However, for those sensitizers with 6-10 thiophene units, the ΔGinject and nc decrease continuously with the increasing of thiophene units. In order to study how the oligothiophene as π-conjugated linker affects light harvesting efficiency of DSSCs, the vibrationally resolved electronic spectra of five metal-free NKX-2587 derivatives with 1-5 thiophene units were simulated within the Franck-Condon approximation including the Herzberg-Teller and Duschinsky effects. The present theoretical results provided helpful guidance for understanding the sources of spectral intensities of dye molecules, and a valuable method for rational design of new molecules to improve the energy conversion efficiency (η) of DSSCs.

  1. Shape dependent resonance light scattering properties of gold nanorods

    Zhu Jian; Huang Liqing; Zhao Junwu; Wang Yongchang; Zhao Yanrui; Hao Limei; Lu Yimin

    2005-01-01

    Suspended gold nanorods with mean aspect ratio 2.5 have been synthesized via electrochemical method. Resonance scattering properties have been studied. Two scattering peaks fixed at 400 and 640 nm are due to the scattering of the gold nanorods via coupling to the transverse and longitudinal surface plasmon resonance. The quasi-static calculation results indicate that with the increasing aspect ratio of the nanorods, the longer wavelength scattering peak red shifts linearly and the shorter wavelength peak blue shifts non-linearly. When aspect ratio a/b = 1.0, ellipse degenerate to sphere and the two peaks unite into one peak at 450 nm

  2. Facile Hydrogen Evolution Reaction on WO3Nanorods

    Rajeswari Janarthanan

    2007-01-01

    Full Text Available AbstractTungsten trioxide nanorods have been generated by the thermal decomposition (450 °C of tetrabutylammonium decatungstate. The synthesized tungsten trioxide (WO3 nanorods have been characterized by XRD, Raman, SEM, TEM, HRTEM and cyclic voltammetry. High resolution transmission electron microscopy and X-ray diffraction analysis showed that the synthesized WO3nanorods are crystalline in nature with monoclinic structure. The electrochemical experiments showed that they constitute a better electrocatalytic system for hydrogen evolution reaction in acid medium compared to their bulk counterpart.

  3. Preparation of ZnS nanorods by ultrasonic waves

    Behboudnia, M.; Majlesara, M.H.; Khanbabaee, B.

    2005-01-01

    ZnS nanorods of approximately 1 μm in length and 20 nm in diameter have been prepared by sonicating ethylenediamine solution of elemental S and zinc acetate in presence of 1-decanthiol under air. The nanorods were characterized using techniques such as X-ray powder diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDAX) and UV-vis absorption spectroscopy. The as-prepared nanorods have regular shape, narrow size distribution and high purity, having band gap of 4.56 eV compared to 3.54 eV corresponding to its bulk single-crystal

  4. Heterogeneous oxidation of diclofenac in the presence of α-MnO2 nanorods: influence of operating factors and mechanism.

    Li, Jian; Zhang, Tuqiao; Ye, Miaomiao

    2015-01-01

    Diclofenac (DCF), one of the pharmaceutical and personal care products that has been widely detected in water, was selected as a model pollutant to evaluate the oxidation activity of α-MnO2 nanorods. The results showed that the heterogeneous oxidation process is highly pH dependent, with higher degradation efficiency at lower pH values. The complete removal of DCF was obtained within 80 min at the solution pH value of 2.5. The oxidation kinetics of DCF can be modeled by Langmuir-Hinshelwood equation (R2>0.999). The effects of various operating parameters, including initial solution pH, α-MnO2 dosage, anions, and cations, on the oxidation efficiency were investigated in detail. A possible reaction pathway for DCF was proposed. In addition, it was demonstrated that the α-MnO2 nanorods can be recycled without decreasing their oxidation activity after 10 cycles.

  5. End-to-end self-assembly of gold nanorods in isopropanol solution: experimental and theoretical studies

    Gordel, M., E-mail: marta.gordel@pwr.edu.pl [Wrocław University of Technology, Advanced Materials Engineering and Modelling Group, Faculty of Chemistry (Poland); Piela, K., E-mail: katarzyna.piela@pwr.edu.pl [Wrocław University of Technology, Department of Physical and Quantum Chemistry (Poland); Kołkowski, R. [Wrocław University of Technology, Advanced Materials Engineering and Modelling Group, Faculty of Chemistry (Poland); Koźlecki, T. [Wrocław University of Technology, Department of Chemical Engineering, Faculty of Chemistry (Poland); Buckle, M. [CNRS, École Normale Supérieure de Cachan, Laboratoire de Biologie et Pharmacologie Appliquée (France); Samoć, M. [Wrocław University of Technology, Advanced Materials Engineering and Modelling Group, Faculty of Chemistry (Poland)

    2015-12-15

    We describe here a modification of properties of colloidal gold nanorods (NRs) resulting from the chemical treatment used to carry out their transfer into isopropanol (IPA) solution. The NRs acquire a tendency to attach one to another by their ends (end-to-end assembly). We focus on the investigation of the change in position and shape of the longitudinal surface plasmon (l-SPR) band after self-assembly. The experimental results are supported by a theoretical calculation, which rationalizes the dramatic change in optical properties when the NRs are positioned end-to-end at short distances. The detailed spectroscopic characterization performed at the consecutive stages of transfer of the NRs from water into IPA solution revealed the features of the interaction between the polymers used as ligands and their contribution to the final stage, when the NRs were dispersed in IPA solution. The efficient method of aligning the NRs detailed here may facilitate applications of the self-assembled NRs as building blocks for optical materials and biological sensing.Graphical Abstract.

  6. Core/shell structured NaYF4:Yb3+/Er3+/Gd+3 nanorods with Au nanoparticles or shells for flexible amorphous silicon solar cells

    Li, Z Q; Li, X D; Liu, Q Q; Chen, X H; Sun, Z; Huang, S M; Liu, C; Ye, X J

    2012-01-01

    A simple approach for preparing near-infrared (NIR) to visible upconversion (UC) NaYF 4 :Yb/Er/Gd nanorods in combination with gold nanostructures has been reported. The grown UC nanomaterials with Au nanostructures have been applied to flexible amorphous silicon solar cells on the steel substrates to investigate their responses to sub-bandgap infrared irradiation. Photocurrent–voltage measurements were performed on the solar cells. It was demonstrated that UC of NIR light led to a 16-fold to 72-fold improvement of the short-circuit current under 980 nm illumination compared to a cell without upconverters. A maximum current of 1.16 mA was obtained for the cell using UC nanorods coated with Au nanoparticles under 980 nm laser illumination. This result corresponds to an external quantum efficiency of 0.14% of the solar cell. Mechanisms of erbium luminescence in the grown UC nanorods were analyzed and discussed. (paper)

  7. Dye-sensitized solar cells based on nanoparticle-decorated ZnO/TiO2 core/shell nanorod arrays

    Wang Meili; Huang Changgang; Cao Yongge; Deng Zhonghua; Liu Yuan; Huang Zhi; Huang Jiquan; Huang Qiufeng; Guo Wang; Liang Jingkui; Yu Qingjiang

    2009-01-01

    Nanoparticles (NPs) decorated ZnO/TiO 2 core/shell nanorod arrays were fabricated on transparent conductive glass substrates by sequential plasma deposition and post-annealing processes for dye-sensitized solar cells (DSSCs) applications. The NPs decorated ZnO/TiO 2 nanorods were composed of single-crystalline ZnO nanorods, homogeneously coated thin TiO 2 shells and entirely covered anatase TiO 2 NPs. The photocurrent density of the composite electrode was largely enhanced due to the enlarged surface area, the dark current was suppressed and the open-circuit voltage was increased because of the energy barrier formed at the interface between the ZnO core and the TiO 2 shell. The increased photocurrent and open-circuit voltage led to an improvement of twice the energy conversion efficiency.

  8. Photothermal ablation cancer therapy using homogeneous CsxWO3 nanorods with broad near-infra-red absorption

    Guo, Chongshen; Yin, Shu; Yu, Haijun; Liu, Shaoqin; Dong, Qiang; Goto, Takehiro; Zhang, Zhiwen; Li, Yaping; Sato, Tsugio

    2013-06-01

    Recently, photothermal ablation therapy (PTA) employing near-infrared radiation (NIR) has been extensively investigated as an emerging modality for cancer management. However, the clinical translation of this promising approach is limited by the lack of PTA agents with broad NIR absorption, low cost and high photothermal conversion efficiency. Herein, we have developed PEGylated homogeneous CsxWO3 nanorods (a mean size ~69.3 nm × 12.8 nm) with broad photo-absorption (780-2500 nm) as a novel NIR absorbent for PTA treatment of human cancer. The prepared CsxWO3 nanocrystals displayed strong near-infrared optical absorption with a high molar extinction coefficient (e.g. 4.8 × 1010 M-1 cm-1 at 980 nm), thus generated significant amounts of heat upon excitation with near-infrared light. The PTA study in two human carcinoma cell lines (i.e. A549 lung cancer cells and HeLa ovarian cancer cells) demonstrated that CsxWO3 nanorods can efficiently cause cell death via hyperthermia induced lysosome destruction, cytoskeleton protein degradation, DNA damage and thereafter cellular necrosis or apoptosis. Our study also confirmed the migration of healthy cells migrated from unirradiated areas to dead cell cycle, which is essential for tissue reconstruction and wound healing after photodestruction of tumor tissue. The prompted results reported in the current study imply the promising potential of CsxWO3 nanorods for application in PTA cancer therapy.Recently, photothermal ablation therapy (PTA) employing near-infrared radiation (NIR) has been extensively investigated as an emerging modality for cancer management. However, the clinical translation of this promising approach is limited by the lack of PTA agents with broad NIR absorption, low cost and high photothermal conversion efficiency. Herein, we have developed PEGylated homogeneous CsxWO3 nanorods (a mean size ~69.3 nm × 12.8 nm) with broad photo-absorption (780-2500 nm) as a novel NIR absorbent for PTA treatment of human

  9. Magnetic field control of fluorescent polymer nanorods

    Kim, Taehyung; He, Le; Bardeen, Christopher J; Morales, Jason R; Beyermann, W P

    2011-01-01

    Nanoscale objects that combine high luminescence output with a magnetic response may be useful for probing local environments or manipulating objects on small scales. Ideally, these two properties would not interfere with each other. In this paper, we show that a fluorescent polymer host material can be doped with high concentrations of 20–30 nm diameter magnetic γ-Fe 2 O 3 particles and then formed into 200 nm diameter nanorods using porous anodic alumina oxide templates. Two different polymer hosts are used: the conjugated polymer polydioctylfluorene and also polystyrene doped with the fluorescent dye Lumogen Red. Fluorescence decay measurements show that 14% by weight loading of the γ-Fe 2 O 3 nanoparticles quenches the fluorescence of the polydioctylfluorene by approximately 33%, but the polystyrene/Lumogen Red fluorescence is almost unaffected. The three-dimensional orientation of both types of nanorods can be precisely controlled by the application of a moderate strength (∼0.1 T) external field with sub-second response times. Transmission electron microscope images reveal that the nanoparticles cluster in the polymer matrix, and these clusters may serve both to prevent fluorescence quenching and to generate the magnetic moment that rotates in response to the applied magnetic field.

  10. Retinal and post-retinal contributions to the Quantum efficiency of the human eye revealed by electrical neuroimaging

    Gibran eManasseh

    2013-11-01

    Full Text Available The retina is one of the best known quantum detectors with rods able to reliably respond to single photons. However, estimates on the number of photons eliciting conscious perception, based on signal detection theory, are systematically above these values after discounting by retinal losses. One possibility is that there is a trade-off between the limited motor resources available to living systems and the excellent reliability of the visual photoreceptors. On this view, the limits to sensory thresholds are not set by the individual reliability of the receptors within each sensory modality (as often assumed but rather by the limited central processing and motor resources available to process the constant inflow of sensory information. To investigate this issue, we reproduced the classical experiment from Hetch aimed to determine the sensory threshold in human vision. We combined a careful physical control of the stimulus parameters with high temporal/spatial resolution recordings of EEG signals and behavioral variables over a relatively large sample of subjects (12. Contrarily to the idea that the limits to visual sensitivity are fully set by the statistical fluctuations in photon absorption on retinal photoreceptors we observed that the state of ongoing neural oscillations before any photon impinges the retina helps to determine if the responses of photoreceptors have access to central conscious processing. Our results suggest that motivational and attentional off-retinal mechanisms play a major role in reducing the QE efficiency of the human visual system when compared to the efficiency of isolated retinal photoreceptors. Yet, this mechanism might subserve adaptive behavior by enhancing the overall multisensory efficiency of the whole system composed by diverse reliable sensory modalities.

  11. HOW OUTSOURCING CAN CONTRIBUTE TO THE EFFICIENCY AND EFFECTIVENESS IN THE PUBLIC SECTOR: SOME INDICATORS ABOUT PORTUGAL

    Maria da Conceição da Costa Marques

    2016-12-01

    Full Text Available Outsourcing is a practice used by different companies to reduce costs by transferring working with outside suppliers rather than performing them internally. Cutting costs are presented as a key benefit in hiring an outsourcing service. Besides to the overall increase efficiency by more rational and efficient allocation of resources, the management of the contract with the external provider allows organizations to adopt more stringent cost control mechanisms, as all components of the relationship with the provider are formalized and systematically evaluated. It also allows the organization to transfer fixed costs to variable costs, reducing the costs related to the acquisition, management, maintenance and updating of equipment, supplies and infrastructure, as well as reduce costs with the management and supervision of teams assigned to non-core activities. The study presented here is an early stage of research to be developed on outsourcing in Portugal and its position in relation to public authorities in other countries. It aims to propose a theoretical model to explain the use of outsourcing in the public sector, as well as a set of variables that may improve understanding of the key determinants of the success of this research.

  12. Diameter Control and Photoluminescence of ZnO Nanorods from Trialkylamines

    Tamar Andelman

    2007-01-01

    Full Text Available A novel solution method to control the diameter of ZnO nanorods is reported. Small diameter (2-3 nm nanorods were synthesized from trihexylamine, and large diameter (50–80 nm nanorods were synthesized by increasing the alkyl chain length to tridodecylamine. The defect (green emission of the photoluminescence (PL spectra of the nanorods varies with diameter, and can thus be controlled by the diameter control. The small ZnO nanorods have strong green emission, while the large diameter nanorods exhibit a remarkably suppressed green band. We show that this observation supports surface oxygen vacancies as the defect that gives rise to the green emission.

  13. Optimized emission in nanorod arrays through quasi-aperiodic inverse design.

    Anderson, P Duke; Povinelli, Michelle L

    2015-06-01

    We investigate a new class of quasi-aperiodic nanorod structures for the enhancement of incoherent light emission. We identify one optimized structure using an inverse design algorithm and the finite-difference time-domain method. We carry out emission calculations on both the optimized structure as well as a simple periodic array. The optimized structure achieves nearly perfect light extraction while maintaining a high spontaneous emission rate. Overall, the optimized structure can achieve a 20%-42% increase in external quantum efficiency relative to a simple periodic design, depending on material quality.

  14. Time-resolved terahertz spectroscopy of conjugated polymer/CdSe nanorod composites

    Cooke, David; Lek, Jun Y.; Krebs, Frederik C

    2010-01-01

    report ultrafast carrier dynamics in hybrid CdSe nanorod / poly(3-hexythiophene) (P3HT) bulk heterojunction films measured by time-resolved terahertz spectroscopy, and compare to the well studied P3HT/phenyl-C61-butyric acid methyl ester (PCBM) blend. Both films show an improved peak...... photoconductivity compared to P3HT alone, consistent with efficient charge transfer. The photoconductivity dynamics show fast, picosecond trapping or recombination in the hybrid blend while the all-organic film shows no such loss of mobile charge over ns time scales. The ac conductivity for all samples is well...

  15. Electrical transport properties of single ZnO nanorods

    Heo, Y.W.; Tien, L.C.; Norton, D.P.; Kang, B.S.; Ren, F.; Gila, B.P.; Pearton, S.J.

    2004-01-01

    Single ZnO nanorods with diameters of ∼130 nm were grown on Au-coated Al 2 O 3 substrates by catalyst-driven molecular beam epitaxy. Individual nanorods were removed from the substrate and placed between Ohmic contact pads and the current-voltage characteristics measured as a function of temperature and gas ambient. In the temperature range from 25 to 150 deg. C, the resistivity of nanorods treated in H 2 at 400 deg. C prior to measurement showed an activation energy of 0.089±0.02 eV and was insensitive to the ambient used (C 2 H 4 ,N 2 O,O 2 or 10% H 2 in N 2 ). By sharp contrast, the conductivity of nanorods not treated in H 2 was sensitive to trace concentrations of gases in the measurement ambient even at room temperature, demonstrating their potential as gas sensors

  16. Nanorotors using asymmetric inorganic nanorods in an optical trap

    Khan, Manas; Sood, A K; Deepak, F L; Rao, C N R

    2006-01-01

    We demonstrate how light force, irrespective of the polarization of the light, can be used to run a simple nanorotor. While the gradient force of a single beam optical trap is used to hold an asymmetric nanorod, we utilize the scattering force to generate a torque on the nanorod, making it rotate about the optic axis. The inherent textural irregularities or morphological asymmetries of the nanorods give rise to the torque under the radiation pressure. Even a small surface irregularity with non-zero chirality is sufficient to produce enough torque for moderate rotational speed. Different sized rotors can be used to set the speed of rotation over a wide range with fine tuning possible through the variation of the laser power. We present a simple dimensional analysis to qualitatively explain the observed trend of the rotational motion of the nanorods

  17. Hydrodynamic fabrication of structurally gradient ZnO nanorods.

    Kim, Hyung Min; Youn, Jae Ryoun; Song, Young Seok

    2016-02-26

    We studied a new approach where structurally gradient nanostructures were fabricated by means of hydrodynamics. Zinc oxide (ZnO) nanorods were synthesized in a drag-driven rotational flow in a controlled manner. The structural characteristics of nanorods such as orientation and diameter were determined by momentum and mass transfer at the substrate surface. The nucleation of ZnO was induced by shear stress which plays a key role in determining the orientation of ZnO nanorods. The nucleation and growth of such nanostructures were modeled theoretically and analyzed numerically to understand the underlying physics of the fabrication of nanostructures controlled by hydrodynamics. The findings demonstrated that the precise control of momentum and mass transfer enabled the formation of ZnO nanorods with a structural gradient in diameter and orientation.

  18. Stimulated emission from ZnO nanorod arrays

    Hauschild, R.; Lange, H.; Priller, H.; Klingshirn, C.; Kalt, H. [Institut fuer Angewandte Physik, Universitaet Karlsruhe (TH), 76128 Karlsruhe (Germany); Kling, R. [Abteilung Halbleiterphysik, Universitaet Ulm, Albert-Einstein Allee 45, 89081 Ulm (Germany); Waag, A. [Institut fuer Halbleitertechnik, TU-Braunschweig, H.-Sommer-Str. 66, 38106 Braunschweig (Germany); Fan, H.J.; Zacharias, M. [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany)

    2006-08-15

    We discuss the time-resolved photoluminescence (PL) spectra of single ZnO nanorods taken at excitation fluences above and below the laser threshold. In the latter case, P-band emission related to polariton-polariton scattering is observed for certain rod geometries while stimulated emission occurs within the electron-hole plasma band. We calculate the intensity distribution of low-order waveguide modes as well as their energy dependence for given nanorod geometries to discuss their relevance with respect to nanorod lasing and polariton propagation. Additional finite-element analysis confirms that a gold layer formed at the nanorod-substrate interface under certain growth conditions leads to an enhancement of confinement within the resonator. (2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  19. Cathodoluminescence of single ZnO nanorod heterostructures

    Piechal, Bernard; Donatini, Fabrice; Dang, Le Si [CNRS-CEA-UJF joint group ' ' Nanophysique et Semiconducteurs' ' , Universite Joseph Fourier (CNRS UMR 5588), Saint Martin d' Heres (France); Yoo, Jinkyoung; Yi, Gyu-Chul [National CRI Center for Semiconductor Nanorods and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang (Korea); Elshaer, Abdelhamid; Mofor, A.C.; Bakin, Andrey; Waag, Andreas [Institute of Semiconductor Technology (IHT), TU Braunschweig (Germany)

    2007-05-15

    Optical properties of ZnO-based single nanorods are probed by cathodoluminescence (CL) measurements at T = 5 K. We observe a variation of the ZnO near band edge CL by three orders of magnitude along the nanorod axis, accompanied by a spectral blueshift of 10-30 meV. This indicates a rather poor structural quality of the nanorod bottom part, close to the substrate. ZnO/ZnMgO quantum wells grown on top of ZnO nanorods are found to exhibit much stronger confinement effects as compared to their two-dimensional counterparts, suggesting a reduced spontaneous and piezoelectric polarization effects. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Soluble Molecularly Imprinted Nanorods for Homogeneous Molecular Recognition

    Rongning Liang

    2018-03-01

    Full Text Available Nowadays, it is still difficult for molecularly imprinted polymers (MIPs to achieve homogeneous recognition since they cannot be easily dissolved in organic or aqueous phase. To address this issue, soluble molecularly imprinted nanorods have been synthesized by using soluble polyaniline doped with a functionalized organic protonic acid as the polymer matrix. By employing 1-naphthoic acid as a model, the proposed imprinted nanorods exhibit an excellent solubility and good homogeneous recognition ability. The imprinting factor for the soluble imprinted nanoroads is 6.8. The equilibrium dissociation constant and the apparent maximum number of the proposed imprinted nanorods are 248.5 μM and 22.1 μmol/g, respectively. We believe that such imprinted nanorods may provide an appealing substitute for natural receptors in homogeneous recognition related fields.

  1. Soluble Molecularly Imprinted Nanorods for Homogeneous Molecular Recognition

    Liang, Rongning; Wang, Tiantian; Zhang, Huan; Yao, Ruiqing; Qin, Wei

    2018-03-01

    Nowadays, it is still difficult for molecularly imprinted polymer (MIPs) to achieve homogeneous recognition since they cannot be easily dissolved in organic or aqueous phase. To address this issue, soluble molecularly imprinted nanorods have been synthesized by using soluble polyaniline doped with a functionalized organic protonic acid as the polymer matrix. By employing 1-naphthoic acid as a model, the proposed imprinted nanorods exhibit an excellent solubility and good homogeneous recognition ability. The imprinting factor for the soluble imprinted nanoroads is 6.8. The equilibrium dissociation constant and the apparent maximum number of the proposed imprinted nanorods are 248.5 μM and 22.1 μmol/g, respectively. We believe that such imprinted nanorods may provide an appealing substitute for natural receptors in homogeneous recognition related fields.

  2. Novel nanorods based on PANI / PEO polymers using electrospinning method

    Al-Hazeem, Nabeel Z., E-mail: nabeelnano333@gmail.com [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Ministry of Education, the General Directorate for Educational Anbar (Iraq); Ahmed, Naser M.; Matjafri, M. Z. [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Sabah, Fayroz A. [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Department of Electrical Engineering, College of Engineering, Al-Mustansiriya University, Baghdad (Iraq); Rasheed, Hiba S. [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Department of Physics, College of Education, Al-Mustansiriya University, Baghdad (Iraq)

    2016-07-06

    In this work, we fabricated nanorods by applying an electric potential on poly (ethylene oxide) (PEO) and polyaniline (PANI) as a polymeric solution by electrospinning method. Testing was conducted on the samples by field emission scanning Electron microscope (FE-SEM), X-ray diffraction (XRD) and Photoluminescence. And the results showed the emergence of nanorods in the sample within glass substrate. Diameters of nanorods have ranged between (52.78-122.40)nm And a length of between (1.15 – 1.32)μm. The emergence of so the results are for the first time, never before was the fabrication of nanorods for polymers using the same method used in this research.

  3. Synthesis and characterization of iron cobalt (FECO) nanorods ...

    Synthesis and characterization of iron cobalt (FECO) nanorods prepared by simple ... shaped by increasing annealing temperature from room temperature to 800 ... Keywords: FeCo nanoparticles, sodium borohydrid, CTAB, chemical synthesis ...

  4. Polarization Raman spectroscopy of GaN nanorod bundles

    Tite, T.; Lee, C. J.; Chang, Y.-M.

    2010-01-01

    We performed polarization Raman spectroscopy on single wurtzite GaN nanorod bundles grown by plasma-assisted molecular beam epitaxy. The obtained Raman spectra were compared with those of GaN epilayer. The spectral difference between the GaN nanorod bundles and epilayer reveals the relaxation of Raman selection rules in these GaN nanorod bundles. The deviation of polarization-dependent Raman spectroscopy from the prediction of Raman selection rules is attributed to both the orientation of the crystal axis with respect to the polarization vectors of incident and scattered light and the structural defects in the merging boundary of GaN nanorods. The presence of high defect density induced by local strain at the merging boundary was further confirmed by transmission electron microscopy. The averaged defect interspacing was estimated to be around 3 nm based on the spatial correlation model.

  5. Improve photovoltaic performance of titanium dioxide nanorods based dye-sensitized solar cells by Ca-doping

    Li, Weixin; Yang, Junyou; Zhang, Jiaqi; Gao, Sheng; Luo, Yubo; Liu, Ming

    2014-01-01

    Highlights: • TiO 2 nanorods doped with Ca ions were synthesized by one-step hydrothermal method. • The flat band edge of rutile TiO 2 shifted positively via Ca-doping. • The photoelectric conversion efficiency of dye-sensitized solar cells (DSSCs) based on TiO 2 electrode was much enhanced by Ca-doping. • A relatively high open circuit voltage was obtained by adopting Ca-doped TiO 2 nanorods electrode. - Abstract: Ca-doped TiO 2 nanorod arrays were prepared via the one-step hydrothermal method successfully, and the effect of Ca ions content on the photovoltaic conversion efficiency of dye-sensitized solar cells has been fully discussed in the paper. Although no obvious change on the microstructure and morphology was observed by field emission scanning electron microscope and transmission electron microscope for the Ca-doped samples, the results of X-ray diffraction and X-ray photoelectron spectroscopy confirmed that Ti 4+ was substituted with Ca 2+ successfully. UV–vis spectroscopy results revealed that the flat band edge shifted positively by Ca ions doping. The photovoltaic conversion efficiency of the dye-sensitized solar cells based on the 2 mol% Ca-doped TiO 2 electrode was 43% higher than that of the undoped one due to the less recombination possibility

  6. Hydrothermal synthesis of CdWO 4 nanorods and their ...

    CdWO4 nanorods with wolframite structure were synthesized in the presence of the surfactant SDBS by a hydrothermal method, and characterized by a variety of techniques. The obtained products are CdWO4 nanorods with length of 0.8–2.5 μm and width of 50–250 nm. The surfactant SDBS plays a key role in the ...

  7. Synthesis and Tribological Properties of WSe2Nanorods

    Yang Jinghai

    2008-01-01

    Full Text Available Abstract The WSe2nanorods were synthesized via solid-state reaction method and characterized by X-ray diffractometer, TEM, and HRTEM. The results indicated the WSe2compounds had rod-like structures with diameters of 10–50 nm and lengths of 100–400 nm, and the growth process of WSe2nanorods was discussed on the basis of the experimental facts. The tribological properties of WSe2nanorods as additives in HVI500 base oil were investigated by UMT-2 multispecimen tribotester. Under the determinate conditions, the friction coefficient of the base oil containing WSe2nanorods was lower than that of the base oil, and decreased with increasing mass fraction of WSe2nanorods when it was <7 wt.%. Moreover, the base oil with the additives was rather suited to high load and high rotating speed. A combination of rolling friction, sliding friction, and stable tribofilm on the rubbing surface could explain the good friction and wear properties of WSe2nanorods as additives.

  8. In vivo toxicity studies of europium hydroxide nanorods in mice

    Patra, Chitta Ranjan; Abdel Moneim, Soha S.; Wang, Enfeng; Dutta, Shamit; Patra, Sujata; Eshed, Michal; Mukherjee, Priyabrata; Gedanken, Aharon; Shah, Vijay H.; Mukhopadhyay, Debabrata

    2009-01-01

    Lanthanide nanoparticles and nanorods have been widely used for diagnostic and therapeutic applications in biomedical nanotechnology due to their fluorescence and pro-angiogenic properties to endothelial cells, respectively. Recently, we have demonstrated that europium (III) hydroxide [Eu III (OH) 3 ] nanorods, synthesized by the microwave technique and characterized by several physico-chemical techniques, can be used as pro-angiogenic agents which introduce future therapeutic treatment strategies for severe ischemic heart/limb disease, and peripheral ischemic disease. The toxicity of these inorganic nanorods to endothelial cells was supported by several in vitro assays. To determine the in vivo toxicity, these nanorods were administered to mice through intraperitoneal injection (IP) everyday over a period of seven days in a dose dependent (1.25 to 125 mg kg -1 day -1 ) and time dependent manner (8-60 days). Bio-distribution of europium elements in different organs was analyzed by inductively coupled plasma mass spectrometry (ICPMS). Short-term (S-T) and long-term (L-T) toxicity studies (mice euthanized on days 8 and 60 for S-T and L-T, respectively) show normal blood hematology and serum clinical chemistry with the exception of a slight elevation of liver enzymes. Histological examination of nanorod-treated vital organs (liver, kidney, spleen and lungs) showed no or only mild histological changes that indicate mild toxicity at the higher dose of nanorods.

  9. Electrodeposition of ZnO nanorods for device application

    Postels, B.; Bakin, A.; Wehmann, H.H.; Suleiman, M.; Waag, A. [Technical University of Braunschweig, Institute of Semiconductor Technology, Braunschweig (Germany); Weimann, T.; Hinze, P. [Physikalische Technische Bundesanstalt, Braunschweig (Germany)

    2008-06-15

    We report the electrochemical growth of zinc oxide nanorods in a zinc nitrate/hexamethylenetetramine solution at 70 C. High-density vertical nanorods were grown on Au films on silicon substrates with a texture coefficient better than 99.9%. By varying the reactant concentration the diameter can be varied between 100 and 250 nm, with corresponding lengths of 1 to 4 {mu}m. Furthermore, this approach was used for the selective growth on Ti/Au strip conductors ordered in an interdigitated structure on an insulating substrate. We achieved the growth of ZnO nanorods between neighbouring strip conductors bridging the gap between them. In this configuration the nanorods are already contacted and electrical measurements can be directly performed. First I-V measurements show a good conductivity of the as-grown nanorods and the resistance could be estimated to be 0.1 {omega}cm. Under UV illumination the ZnO nanorods demonstrate a photoconductivity, but only after annealing the sample at 300 C in N{sub 2}. (orig.)

  10. Polarized Raman scattering of single ZnO nanorod

    Yu, J. L.; Lai, Y. F.; Wang, Y. Z.; Cheng, S. Y.; Chen, Y. H.

    2014-01-01

    Polarized Raman scattering measurement on single wurtzite c-plane (001) ZnO nanorod grown by hydrothermal method has been performed at room temperature. The polarization dependence of the intensity of the Raman scattering for the phonon modes A 1 (TO), E 1 (TO), and E 2 high in the ZnO nanorod are obtained. The deviations of polarization-dependent Raman spectroscopy from the prediction of Raman selection rules are observed, which can be attributed to the structure defects in the ZnO nanorod as confirmed by the comparison of the transmission electron microscopy, photoluminescence spectra as well as the polarization dependent Raman signal of the annealed and unannealed ZnO nanorod. The Raman tensor elements of A 1 (TO) and E 1 (TO) phonon modes normalized to that of the E 2 high phonon mode are |a/d|=0.32±0.01, |b/d|=0.49±0.02, and |c/d|=0.23±0.01 for the unannealed ZnO nanorod, and |a/d|=0.33±0.01, |b/d|=0.45±0.01, and |c/d|=0.20±0.01 for the annealed ZnO nanorod, which shows strong anisotropy compared to that of bulk ZnO epilayer

  11. Selective Facet Reactivity During Cation Exchange in Cadmium Sulfide Nanorods

    Sadtler, Bryce; Demchenko, Denis; Zheng, Haimei; Hughes, Steven; Merkle, Maxwell; Dahmen, Ulrich; Wang, Lin-Wang; Alivisatos, A. Paul

    2008-12-18

    The partial transformation of ionic nanocrystals through cation exchange has been used to synthesize nanocrystal heterostructures. We demonstrate that the selectivity for cation exchange to take place at different facets of the nanocrystal plays an important role in determining the resulting morphology of the binary heterostructure. In the case of copper I (Cu+) cation exchange in cadmium sulfide (CdS) nanorods, the reaction starts preferentially at the ends of the nanorods such that copper sulfide (Cu2S) grows inwards from either end. The resulting morphology is very different from the striped pattern obtained in our previous studies of silver I (Ag+) exchange in CdS nanorods where non-selective nucleation of silver sulfide (Ag2S) occurs. From interface formation energies calculated for several models of epitaxialconnections between CdS and Cu2S or Ag2S, we infer the relative stability of each interface during the nucleation and growth of Cu2S or Ag2S within the CdS nanorods. The epitaxial connections of Cu2S to the end facets of CdS nanorods minimize the formation energy, making these interfaces stable throughout the exchange reaction. However, as the two end facets of wurtzite CdS nanorods are crystallographically nonequivalent, asymmetric heterostructures can be produced.

  12. Asymmetric monometallic nanorod nanoparticle dimer and related compositions and methods

    Han, Yu

    2016-03-31

    The fabrication of asymmetric monometallic nanocrystals with novel properties for plasmonics, nanophotonics and nanoelectronics. Asymmetric monometallic plasmonic nanocrystals are of both fundamental synthetic challenge and practical significance. In an example, a thiol-ligand mediated growth strategy that enables the synthesis of unprecedented Au Nanorod-Au Nanoparticle (AuNR-AuNP) dimers from pre-synthesized AuNR seeds. Using high-resolution electron microscopy and tomography, crystal structure and three-dimensional morphology of the dimer, as well as the growth pathway of the AuNP on the AuNR seed, was investigated for this example. The dimer exhibits an extraordinary broadband optical extinction spectrum spanning the UV, visible, and near infrared regions (300 - 1300 nm). This unexpected property makes the AuNR-AuNP dimer example useful for many nanophotonic applications. In two experiments, the dimer example was tested as a surface- enhanced Raman scattering (SERS) substrate and a solar light harvester for photothermal conversion, in comparison with the mixture of AuNR and AuNP. In the SERS experiment, the dimer example showed an enhancement factor about 10 times higher than that of the mixture, when the excitation wavelength (660 nm) was off the two surface plasmon resonance (SPR) bands of the mixture. In the photothermal conversion experiment under simulated sunlight illumination, the dimer example exhibited an energy conversion efficiency about 1.4 times as high as that of the mixture.

  13. Bioenergy: Resource efficiency and contributions to energy- and climate policy objectives; Bioenergi: Resurseffektivitet och bidrag till energi- och klimatpolitiska maal

    Berndes, Goeran; Karlsson, Sten [Chalmers Univ. of Technology, SE-412 96 Goeteborg (Sweden). Div. of Physical Resource Theory; Boerjesson, Paal; Rosenqvist, Haakan [Lund Univ., Lund (Sweden). Environmental and Energy Systems Studies

    2008-09-15

    Increasing the use of bioenergy in place of fossil fuels is motivated by a number of energy policy goals. Individual bioenergy systems must be evaluated relative to a particular goal or set of goals. Depending on which specific political goal that is in focus, the attractiveness of different bioenergy systems can vary in relation to even broad objectives such as the resource-efficient use of agricultural and forest land. Furthermore, the outcome of a specific evaluation is sensitive to explicit as well as implicit assumptions and choices regarding, e.g., definition of system boundaries, economic conditions, implementation of policies, byproduct markets, and establishment of new technologies. Several biofuels production chains generate byproducts of value. Energy balance calculations are greatly influenced by how such byproducts are taken into account. Often, the most important factor underlying different results from different energy balance studies is a difference in analytic assumptions, for instance in allocation methods and system borders. Different studies can only be accurately compared if they are based on comparable analytic assumptions. Which methods are justified in a given energy balance study is determined by the current conditions for the specific bioenergy system under analysis. In the future, bioenergy systems may increasingly consist of various generation combinations wherein liquid biofuels may for instance be co-generated with power, heat, and solid biofuels, etc. from a mix of raw biomass. The driving factors are the synergies available with the higher total energy efficiency and resources efficiency obtained by combined approaches, compared to when the energy carriers are produced on their own. These solutions imply that if there is a market for the other energy carriers, and the total net system exchange is high, a lower net value for liquid fuels may be acceptable. The climate efficiency of a bioenergy system also depends on its impact on

  14. Membrane Microdomain Structures of Liposomes and Their Contribution to the Cellular Uptake Efficiency into HeLa Cells.

    Onuki, Yoshinori; Obata, Yasuko; Kawano, Kumi; Sano, Hiromu; Matsumoto, Reina; Hayashi, Yoshihiro; Takayama, Kozo

    2016-02-01

    The purpose of this study is to obtain a comprehensive relationship between membrane microdomain structures of liposomes and their cellular uptake efficiency. Model liposomes consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/cholesterol (Ch) were prepared with various lipid compositions. To detect distinct membrane microdomains in the liposomes, fluorescence-quenching assays were performed at temperatures ranging from 25 to 60 °C using 1,6-diphenyl-1,3,5-hexatriene-labeled liposomes and (2,2,6,6-tetramethylpiperidin-1-yl)oxyl. From the data analysis using the response surface method, we gained a better understanding of the conditions for forming distinct domains (Lo, Ld, and gel phase membranes) as a function of lipid composition. We further performed self-organizing maps (SOM) clustering to simplify the complicated behavior of the domain formation to obtain its essence. As a result, DPPC/DOPC/Ch liposomes in any lipid composition were integrated into five distinct clusters in terms of similarity of the domain structure. In addition, the findings from synchrotron small-angle X-ray scattering analysis offered further insight into the domain structures. As a last phase of this study, an in vitro cellular uptake study using HeLa cells was conducted using SOM clusters' liposomes with/without PEGylation. As a consequence of this study, higher cellular uptake was observed from liposomes having Ch-rich ordered domains.

  15. Influence of PEG coating on optical and thermal response of gold nanoshperes and nanorods

    Chen, Qin; Ren, Yatao; Qi, Hong; Ruan, Liming

    2018-06-01

    PEGylation is widely applied as a surface modification method for nanoparticles in biomedical applications to improve their biological properties, including biocompatibility and immunogenicity. In most of its biomedical applications, nanoparticles are served as optical or thermal contrast agents. Therefore, the impact of poly (ethylene glycol) (PEG) coating thickness on the optical and thermal properties of nanoparticles needs to be further investigated. In the present work, we studied two kinds of commonly used nanoparticles, including nanosphere and nanorod. The temperature and electric fields are obtained for nanoparticles with different PEG coating thicknesses. It is found that the change of PEG coating thickness on gold nanospheres only has impact on the absolute value of maximum absorption and scattering efficiencies, which barely influences the LSPR wavelength λmax and other optical and thermal characteristics. In contrast, for nanorod, the maximum efficiencies are barely influenced by the variation of PEG coating thickness. On the other hand, the localized surface plasmon resonance wavelength has an evident red shift with the increasing of PEG coating thickness. The maximum absorption efficiency is a way to evaluate the energy dissipation rate, which decides the scale of the heat source induced by nanoparticles. These findings are crucial for the accurate prediction of optical and thermal properties of nanoparticles in biomedical application. The present work also presents a possible way to manipulate the optical and thermal behaviors of nanoparticles in the application of biomedicine without changing the morphology of nanoparticles.

  16. Electrochemical properties of TiO{sub 2} encapsulated ZnO nanorod aggregates dye sensitized solar cells

    Justin Raj, C.; Karthick, S.N.; Dennyson Savariraj, A.; Hemalatha, K.V.; Park, Song-Ki; Kim, Hee-Je [Pusan National University, Department of Electrical Engineering, San 30, Jangjeong-Dong, Gumjeong-Ku, Busan 609 735 (Korea, Republic of); Prabakar, K., E-mail: prabakar@pusan.ac.kr [Pusan National University, Department of Electrical Engineering, San 30, Jangjeong-Dong, Gumjeong-Ku, Busan 609 735 (Korea, Republic of)

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer ZnO nanorod aggregates were synthesized by simple co-precipitation technique. Black-Right-Pointing-Pointer TiO{sub 2} encapsulated ZnO nanorod aggregates photoanode was used for the DSSC. Black-Right-Pointing-Pointer TiO{sub 2} encapsulated ZnO nanorod aggregates shows an enhanced efficiency. Black-Right-Pointing-Pointer The electron recombination and transport properties were studied using EIS method. - Abstract: Dye sensitized solar cells based on TiO{sub 2} encapsulated ZnO nanorod (NR) aggregates were fabricated and electrochemical performance was analyzed using impedance spectroscopy as a function of forward bias voltage. Charge transfer properties such as electron life time ({tau}{sub n}), electron diffusion coefficient (D{sub n}) and electron diffusion length (L{sub n}) were calculated in order to ensure the influence of TiO{sub 2} layer over the ZnO NR aggregates. It is found that the short circuit current density (Jsc = 5.8 mA cm{sup -2}), open circuit potential (V{sub oc} = 0.743 V), fill factor (FF = 0.57) and conversion efficiency are significantly improved by the introduction of TiO{sub 2} layer over ZnO photoanode. A power conversion efficiency of about 2.48% has been achieved for TiO{sub 2}/ZnO cell, which is higher than that of bare ZnO NR aggregate based cells (1.73%). The formation of an inherent energy barrier between TiO{sub 2} and ZnO films and the passivation of surface traps on the ZnO film caused by the introduction of TiO{sub 2} layer increase the dye absorption and favor the electron transport which may be responsible for the enhanced performance of TiO{sub 2}/ZnO cell.

  17. Electrochemical properties of TiO2 encapsulated ZnO nanorod aggregates dye sensitized solar cells

    Justin Raj, C.; Karthick, S.N.; Dennyson Savariraj, A.; Hemalatha, K.V.; Park, Song-Ki; Kim, Hee-Je; Prabakar, K.

    2012-01-01

    Highlights: ► ZnO nanorod aggregates were synthesized by simple co-precipitation technique. ► TiO 2 encapsulated ZnO nanorod aggregates photoanode was used for the DSSC. ► TiO 2 encapsulated ZnO nanorod aggregates shows an enhanced efficiency. ► The electron recombination and transport properties were studied using EIS method. - Abstract: Dye sensitized solar cells based on TiO 2 encapsulated ZnO nanorod (NR) aggregates were fabricated and electrochemical performance was analyzed using impedance spectroscopy as a function of forward bias voltage. Charge transfer properties such as electron life time (τ n ), electron diffusion coefficient (D n ) and electron diffusion length (L n ) were calculated in order to ensure the influence of TiO 2 layer over the ZnO NR aggregates. It is found that the short circuit current density (Jsc = 5.8 mA cm −2 ), open circuit potential (V oc = 0.743 V), fill factor (FF = 0.57) and conversion efficiency are significantly improved by the introduction of TiO 2 layer over ZnO photoanode. A power conversion efficiency of about 2.48% has been achieved for TiO 2 /ZnO cell, which is higher than that of bare ZnO NR aggregate based cells (1.73%). The formation of an inherent energy barrier between TiO 2 and ZnO films and the passivation of surface traps on the ZnO film caused by the introduction of TiO 2 layer increase the dye absorption and favor the electron transport which may be responsible for the enhanced performance of TiO 2 /ZnO cell.

  18. Proteins YlaJ and YhcN contribute to the efficiency of spore germination in Bacillus subtilis.

    Johnson, Christian L; Moir, Anne

    2017-04-01

    The YlaJ and YhcN spore lipoproteins of Bacillus subtilis contain a common domain, and are of unknown function. Homologues of YlaJ or YhcN are widespread in Bacilli and are also encoded in those Clostridia that use cortex lytic enzymes SleB and CwlJ for cortex hydrolysis during germination. In B. subtilis, we report that single and double mutants lacking YlaJ and/or YhcN show a reduced rate of spore germination in L-alanine, with a delay in loss of heat resistance, release of dipicolinic acid and OD fall. If B. subtilis spores lack the cortex lytic enzyme CwlJ, spore cortex degradation and subsequent outgrowth to form colonies is strictly dependent on the other cortex lytic enzyme SleB, allowing a test of SleB function; in a cwlJ mutant background, the combined loss of both ylaJ and yhcN genes resulted in a spore population in which only 20% of spores germinated and outgrew to form colonies, suggesting that SleB activity is compromised. YlaJ and YhcN have a role in germination that is not yet well defined, but these proteins are likely to contribute, directly or indirectly, to early events in germination, including effective SleB function. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Contribution of Online Trading of Used Goods to Resource Efficiency: An Empirical Study of eBay Users

    Jens Clausen

    2010-06-01

    Full Text Available This paper discusses the sustainability impact (contribution to sustainability, reduction of adverse environmental impacts of online second-hand trading. A survey of eBay users shows that a relationship between the trading of used goods and the protection of natural resources is hardly realized. Secondly, the environmental motivation and the willingness to act in a sustainable manner differ widely between groups of consumers. Given these results from a user perspective, the paper tries to find some objective hints of online second-hand trading’s environmental impact. The greenhouse gas emissions resulting from the energy used for the trading transactions seem to be considerably lower than the emissions due to the (avoided production of new goods. The paper concludes with a set of recommendations for second-hand trade and consumer policy. Information about the sustainability benefits of purchasing second-hand goods should be included in general consumer information, and arguments for changes in behavior should be targeted to different groups of consumers.

  20. Electrical properties of ZnO nanorods and layers

    Schlenker, Eva; Bakin, Andrey; Peters, Ole; Mofor, Augustine C.; Postels, Bianca; El-Shaer, Hamid; Wehmann, Hergo-Heinrich; Waag, Andreas [Institut fuer Halbleitertechnik, TU Braunschweig (Germany); Weimann, Thomas; Hinze, Peter [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany)

    2007-07-01

    ZnO has attracted a lot of interest in the scientific community due to its outstanding properties. With a band gap of 3.37 eV and an exciton binding energy of 60 meV it is a promising candidate for micro- and optoelectronic applications. The growth of ZnO nanostructures and epitaxial layers is well under control and their optical and structural properties are already thoroughly characterized. However, due to contacting difficulties, less reports exist on the electrical properties of single ZnO nanostructures. In this contribution we present various contacting methods in order to explore the electrical properties of individual nanorods either grown by aqueous chemical growth or vapor phase transport. Current-Voltage characteristics were obtained by using an atomic force microscope with a conductive tip or by patterning contacts with e-beam lithography. The results are compared to the ones obtained from measurements on epitaxially grown ZnO layers and first applications are presented.

  1. Control of ZnO Nanorod Defects to Enhance Carrier Transportation in p-Cu₂O/i-ZnO Nanorods/n-IGZO Heterojunction.

    Ke, Nguyen Huu; Trinh, Le Thi Tuyet; Mung, Nguyen Thi; Loan, Phan Thi Kieu; Tuan, Dao Anh; Truong, Nguyen Huu; Tran, Cao Vinh; Hung, Le Vu Tuan

    2017-01-01

    The p-Cu₂O/i-ZnO nanorods/n-IGZO heterojunctions were fabricated by electrochemical and sputtering method. ZnO nanorods were grown on conductive indium gallium zinc oxide (IGZO) thin film and then p-Cu₂O layer was deposited on ZnO nanorods to form the heterojunction. ZnO nanorods play an important role in carrier transport mechanisms and performance of the junction. The changing of defects in ZnO nanorods by annealing samples in air and vacuum have studied. The XRD, photoluminescence (PL) spectroscopy, and FTIR were used to study about structure, and defects in ZnO nanorods. The SEM, i–V characteristics methods were also used to define structure, electrical properties of the heterojunctions layers. The results show that the defects in ZnO nanorods affected remarkably on performance of heterojunctions of solar cells.

  2. Preparation of ZnO nanorods on conductive PET-ITO-Ag fibers

    Li, Yiwen; Ji, Shuai; Chen, Yuanyu; Zhang, Hong; Gong, Yumei, E-mail: ymgong@dlpu.edu.cn; Guo, Jing, E-mail: guojing8161@163.com

    2016-12-01

    Highlights: • Polymeric PET fibers were conductive modified by ITO and the subsequent Ag coating. The conductive PET-ITO-Ag fiber has the surface resistivity as low as 0.23 mΩ cm. The PET-ITO-Ag fiber was used as a basal material to plant vertical ZnO nanorods. - Abstract: We studied the vertical ZnO nanorods grown on conductive conventional polyethylene terephthalate (PET) fibers which are prepared by electroless silver depositing on tin-doped indium oxide (ITO) coated PET fibers through an efficient and low-cost green approach. The PET fibers were firstly functionalized with a layer of ITO gel synthesized through a sol–gel process at rather low temperature, simply by immersing the fibers into ITO sol for several minutes followed by gelation at 120 °C. Once the ITO gel layer surface was activated by SnCl{sub 2}, a continuous, uniform, and compact layer of silver was carried out on the surface of the PET-ITO fibers through electroless plating operation at room temperature. The as-prepared PET-ITO-Ag fibers had good electrical conductivity, with surface resistivity as low as 0.23 mΩ cm. The overall procedure is simple, efficient, nontoxic, and controllable. The conductive PET-ITO-Ag fiber was used successfully as a flexible basal material to plant vertical ZnO nanorods through controlling the seeding and growth processes. The morphology of the PET-ITO, PET-ITO-Ag, and PET-ITO-Ag-ZnO fibers were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Undergone the whole process, although the tensile strength of the fiber decreased slightly, they may still exert their applications in flexible electronic such as photovoltaic and piezoelectric devices.

  3. Assessment of Anisotropic Semiconductor Nanorod and Nanoplatelet Heterostructures with Polarized Emission for Liquid Crystal Display Technology.

    Cunningham, Patrick D; Souza, João B; Fedin, Igor; She, Chunxing; Lee, Byeongdu; Talapin, Dmitri V

    2016-06-28

    Semiconductor nanorods can emit linear-polarized light at efficiencies over 80%. Polarization of light in these systems, confirmed through single-rod spectroscopy, can be explained on the basis of the anisotropy of the transition dipole moment and dielectric confinement effects. Here we report emission polarization in macroscopic semiconductor-polymer composite films containing CdSe/CdS nanorods and colloidal CdSe nanoplatelets. Anisotropic nanocrystals dispersed in polymer films of poly butyl-co-isobutyl methacrylate (PBiBMA) can be stretched mechanically in order to obtain unidirectionally aligned arrays. A high degree of alignment, corresponding to an orientation factor of 0.87, was achieved and large areas demonstrated polarized emission, with the contrast ratio I∥/I⊥ = 5.6, making these films viable candidates for use in liquid crystal display (LCD) devices. To some surprise, we observed significant optical anisotropy and emission polarization for 2D CdSe nanoplatelets with the electronic structure of quantum wells. The aligned nanorod arrays serve as optical funnels, absorbing unpolarized light and re-emitting light from deep-green to red with quantum efficiencies over 90% and high degree of linear polarization. Our results conclusively demonstrate the benefits of anisotropic nanostructures for LCD backlighting. The polymer films with aligned CdSe/CdS dot-in-rod and rod-in-rod nanostructures show more than 2-fold enhancement of brightness compared to the emitter layers with randomly oriented nanostructures. This effect can be explained as the combination of linearly polarized luminescence and directional emission from individual nanostructures.

  4. Preparation of ZnO nanorods on conductive PET-ITO-Ag fibers

    Li, Yiwen; Ji, Shuai; Chen, Yuanyu; Zhang, Hong; Gong, Yumei; Guo, Jing

    2016-01-01

    Highlights: • Polymeric PET fibers were conductive modified by ITO and the subsequent Ag coating. The conductive PET-ITO-Ag fiber has the surface resistivity as low as 0.23 mΩ cm. The PET-ITO-Ag fiber was used as a basal material to plant vertical ZnO nanorods. - Abstract: We studied the vertical ZnO nanorods grown on conductive conventional polyethylene terephthalate (PET) fibers which are prepared by electroless silver depositing on tin-doped indium oxide (ITO) coated PET fibers through an efficient and low-cost green approach. The PET fibers were firstly functionalized with a layer of ITO gel synthesized through a sol–gel process at rather low temperature, simply by immersing the fibers into ITO sol for several minutes followed by gelation at 120 °C. Once the ITO gel layer surface was activated by SnCl 2 , a continuous, uniform, and compact layer of silver was carried out on the surface of the PET-ITO fibers through electroless plating operation at room temperature. The as-prepared PET-ITO-Ag fibers had good electrical conductivity, with surface resistivity as low as 0.23 mΩ cm. The overall procedure is simple, efficient, nontoxic, and controllable. The conductive PET-ITO-Ag fiber was used successfully as a flexible basal material to plant vertical ZnO nanorods through controlling the seeding and growth processes. The morphology of the PET-ITO, PET-ITO-Ag, and PET-ITO-Ag-ZnO fibers were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Undergone the whole process, although the tensile strength of the fiber decreased slightly, they may still exert their applications in flexible electronic such as photovoltaic and piezoelectric devices.

  5. Contribution of Nitrogen Uptake and Retranslocation during Reproductive Growth to the Nitrogen Efficiency of Winter Oilseed-Rape Cultivars (Brassica napus L. Differing in Leaf Senescence

    Fabian Koeslin-Findeklee

    2016-01-01

    Full Text Available Genotypic variation in N efficiency defined as high grain yield under limited nitrogen (N supply of winter oilseed-rape line-cultivars has been predominantly attributed to N uptake efficiency (NUPT through maintained N uptake during reproductive growth related to functional stay-green. For investigating the role of stay-green, N retranslocation and N uptake during the reproductive phase for grain yield formation, two line cultivars differing in N starvation-induced leaf senescence were grown in a field experiment without mineral N (N0 and with 160 kg N·ha−1 (N160. Through frequent harvests from full flowering until maturity N uptake, N utilization and apparent N remobilization from vegetative plant parts to the pods could be calculated. NUPT proved being more important than N utilization efficiency (NUE for grain yield formation under N-limiting (N0 conditions. For cultivar differences in N efficiency, particularly N uptake during flowering (NUPT and biomass allocation efficiency (HI to the grains, were decisive. Both crop traits were related to delayed senescence of the older leaves. Remobilization of N particularly from stems and leaves was more important for pod N accumulation than N uptake after full flowering. Pod walls (high N concentrations and stems (high biomass mainly contributed to the crop-residue N at maturity. Decreasing the crop-inherent high N budget surplus of winter oilseed-rape requires increasing the low N remobilization efficiency particularly of pod-wall N to the grains. Addressing this conclusion, multi-year and -location field experiments with an extended range of cultivars including hybrids are desirable.

  6. Fabricating hydroxyapatite nanorods using a biomacromolecule template

    Zhu Aiping, E-mail: apzhu@yzu.edu.cn [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Lu Yan; Si Yunfeng [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Dai Sheng [School of Chemical Engineering, University of Adelaide, Adelaide, SA 5005 (Australia)

    2011-02-01

    Rod-like hydroxyapatite (HAp) nanoparticles with various aspect ratios are synthesized by means of low-temperature hydrothermal method in the presence of a N-[(2-hydroxy-3-trimethylammonium) propyl]chitosan chloride (HTCC) template. The synthesized HAps were examined by X-ray diffraction (XRD), Fourier transform infrared spectrophotometer (FTIR) and transmission electron microscopy (TEM) techniques. The results reveal that HAps are rod-like monocrystals, where the size and morphology can be tailored by varying synthesis conditions, such as pH, hydrothermal synthesis temperature and the ratio of PO{sub 4}{sup 3-} to the quaternary ammonium in HTCC. The mechanism of HTCC template on HAp nanorod preparation is analyzed.

  7. Contribution to the enhancement of the energy efficiency in electrical / electronic architectures of automobiles; Beitrag zur Steigerung der Energieeffizienz in Kfz-Elektrik-/Elektronik-Architekturen

    Goerber, Matthias

    2013-06-01

    Increasing customer demands for enhanced comfort, safety or assistance functions provide automotive manufacturers with high demands in their product development process. At the same time the criterion of environmental friendliness of the automobile gained more and more importance. These requirements mean that the electrical / electronic architecture of a vehicle is becoming important increasingly. Under this aspect, the author of the contribution under consideration reports on the criterion of energy efficiency of electrical / electronic architecture and its influence on fuel consumption and range of vehicles.

  8. MnO{sub 2} nanorods/3D-rGO composite as high performance anode materials for Li-ion batteries

    Liu, Hongdong; Hu, Zhongli; Su, Yongyao; Ruan, Haibo; Hu, Rong [Research Institute for New Materials Technology, Chongqing University of Arts and Sciences, Chongqing 402160 (China); Zhang, Lei, E-mail: leizhang0215@126.com [College of Life Science, Chongqing Normal University, Chongqing 401331 (China)

    2017-01-15

    Highlights: • MnO{sub 2} nanorods/3D-rGO composite has been synthesized by a simple in situ hydrothermal methord. • MnO{sub 2} nanorods/3D-rGO composite exhibits high reversible capacity, outstanding rate capacity and excellent cyclic stability. • Building metal oxides/3D-rGO composite is an effective way for improving the electrochemical performance of Li-ion batteries. - Abstract: MnO{sub 2} nanorods/three-dimensional reduced graphene oxide (3D-rGO) composite has been synthesized by a simple in situ hydrothermal methord. The X-ray diffraction (XRD) pattern of the as-prepared composite reveals tetragonal structure of α-MnO{sub 2.} Raman spectroscopic and X-ray photoelectron spectroscopy (XPS) of the samples confirm the coexistence of MnO{sub 2} and graphene. The Brunauer-Emmett-Teller (BET) analysis shows the large surface area of the composite. The electron microscopy images of the as-synthesized products reveals the MnO{sub 2} nanorods are homogeneously grown on 3D-rGO matrix. Electrochemical characterization exhibits the MnO{sub 2} nanorods/3D-rGO composite with large reversible capacity (595 mA h g{sup −1} over 60 cycles at 100 mA g{sup −1}), high coulombic efficiency (above 99%), excellent rate capability and good cyclic stability. The superior electrochemical performance can be attributed to the turf-like nanostructure of composite, high capacity of MnO{sub 2} and superior electrical conductivity of 3D-rGO. It suggests that MnO{sub 2} nanorods/3D-rGO composite will be a promising anode material for Li-ion batteries.

  9. Facile synthesis of nanorod-type graphitic carbon nitride/Fe2O3 composite with enhanced photocatalytic performance

    Wang, Jiangpeng; Li, Changqing; Cong, Jingkun; Liu, Ziwei; Zhang, Hanzhuo; Liang, Mei; Gao, Junkuo; Wang, Shunli; Yao, Juming

    2016-01-01

    Here we report a facile synthesis of nanorod-type graphitic carbon nitride/Fe 2 O 3 composite (Fe 2 O 3 -g-C 3 N 4 ) by using Fe-melamine supramolecular framework as precursor. The chemical and optical properties of the nanocomposites are well-characterized. The Fe 2 O 3 -g-C 3 N 4 nanocomposite demonstrated excellent photocatalytic activities under visible light due to the efficient utilization of sunlight and the construction of Z-scheme electron transfer pathway. The results indicated that it could be a promising approach for the preparation of efficient g-C 3 N 4 nanocomposites photocatalysts by using metal-melamine supramolecular framework as precursors. - Graphical abstract: Nanorod-type graphitic carbon nitride/Fe 2 O 3 composite (Fe 2 O 3 -g-C 3 N 4 ) was synthesized by using Fe-melamine supramolecular framework as precursor. The Fe 2 O 3 -g-C 3 N 4 nanocomposite demonstrated excellent photocatalytic activities under visible light. Display Omitted - Highlights: • Nanorod-type graphitic carbon nitride/Fe 2 O 3 composite (Fe 2 O 3 -g-C 3 N 4 ) was synthesized. • Fe 2 O 3 -g-C 3 N 4 showed strong optical absorption in the visible-light region. • The Fe 2 O 3 -g-C 3 N 4 nanocomposite demonstrated excellent photocatalytic activities.

  10. Synthesis of gold nanorod-embedded polymeric nanoparticles by a nanoprecipitation method for use as photothermal agents

    Kim, Eunjung; Choi, Jihye; Haam, Seungjoo [Department of Chemical and Biomolecular Engineering, College of Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Yang, Jaemoon; Suh, Jin-Suck; Huh, Yong-Min, E-mail: ej.kim@yonsei.ac.k, E-mail: 177hum@yonsei.ac.k, E-mail: jjakji2@yonsei.ac.k, E-mail: jss@yuhs.a, E-mail: ymhuh@yuhs.a, E-mail: haam@yonsei.ac.k [Department of Radiology, College of Medicine, Yonsei University, Seoul 120-752 (Korea, Republic of)

    2009-09-09

    For the synthesis of biocompatible photothermal agents, gold nanorod-embedded polymeric nanoparticles (GPNs) were synthesized using a nanoprecipitation method. Uniform gold nanorods (GNRs), which are sensitive to a photothermal effect by near-infrared (NIR) light, with an aspect ratio of 4.0 were synthesized by a seed-mediated growth method. The hydroxyl groups of polycaprolactone diol (PCL diOH) were modified by esterification with mercaptopropionic acid to give a dithiol (polycaprolactone dithiol, PCL diSH) as a phase transfer and capping agent. Subsequently, hexadecyltrimethylammonium bromide (CTAB), a stabilizer of GNRs, was exchanged and/or removed by PCL diSH. PCL diSH-coated GNRs were further wrapped in a hydrophilic polymer, Pluronic F127, as a stabilizer. These newly formulated GPNs exhibit excellent stability in water and a maximum absorbance in the NIR region indicating a highly efficient surface plasmon resonance effect, phenomena useful for photothermal agents.

  11. Sub-coherent growth of ZnO nanorod arrays on three-dimensional graphene framework as one-bulk high-performance photocatalyst

    Yu, Mei; Ma, Yuxiao; Liu, Jianhua; Li, Xinjie; Li, Songmei; Liu, Shenyao

    2016-12-01

    Highly ordered ZnO nanorod arrays were grown vertically on the surface of three-dimensional graphene (3DG) framework bulk to prepare a one-bulk structure. In such structure, ZnO exhibits outstanding photocatalyst performance due to its hybridization with 3DG. The sub-coherency between ZnO and 3DG ensures the template-free growth of ZnO nanorod arrays and the exposing of its most active crystal surfaces {0001}. The hybridization prevents the agglomeration of ZnO nanoparticles, helping the formation of nanorod array morphology, enhancing the mass transfer of reactants and the separation of photogenerated holes. In the efficiency test, with tiny amount of ZnO catalyst (∼5.03 × 10-3 g), the concentration of methyl orange decreased to ∼11% of the initial value within four hours. The structure possesses high average photocatalytic efficiency of 6.56 × 10-3 h-1, much higher than that of bare ZnO nanorods.

  12. Schottky diodes between Bi2S3 nanorods and metal nanoparticles in a polymer matrix as hybrid bulk-heterojunction solar cells

    Saha, Sudip K.; Pal, Amlan J.

    2015-01-01

    We report the use of metal-semiconductor Schottky junctions in a conjugated polymer matrix as solar cells. The Schottky diodes, which were formed between Bi 2 S 3 nanorods and gold nanoparticles, efficiently dissociated photogenerated excitons. The bulk-heterojunction (BHJ) devices based on such metal-semiconductor Schottky diodes in a polymer matrix therefore acted as an efficient solar cell as compared to the devices based on only the semiconductor nanorods in the polymer matrix or when gold nanoparticles were added separately to the BHJs. In the latter device, gold nanoparticles offered plasmonic enhancement due to an increased cross-section of optical absorption. We report growth and characteristics of the Schottky junctions formed through an intimate contact between Bi 2 S 3 nanorods and gold nanoparticles. We also report fabrication and characterization of BHJ solar cells based on such heterojunctions. We highlight the benefit of using metal-semiconductor Schottky diodes over only inorganic semiconductor nanorods or quantum dots in a polymer matrix in forming hybrid BHJ solar cells

  13. Self-propelled micromotors based on Au-mesoporous silica nanorods

    Wang, Ying-Shuai; Xia, Hong; Lv, Chao; Wang, Lei; Dong, Wen-Fei; Feng, Jing; Sun, Hong-Bo

    2015-07-01

    Here, a chemical powered micromotor from the assembly of Au-SiO2 nanorods is presented. This new micromotor can be propelled efficiently by hydrogen bubbles generated from a hydrolysis reaction of aqueous NaBH4 and KBH4 and by oxygen bubbles produced by decomposition of H2O2. The monodisperse Au nanoparticles in mesoporous silica particles could catalyze the decomposition of two different kinds of fuels and produce bubbles. High speeds of 80 μm s-1 and recycles of more than 30 times are achieved in both NaBH4 and H2O2 media. Locomotion and rolling forms of movement were found. The locomotion forms can be obtained in a larger proportion by patterning the Au-SiO2 nanorods and a PDMS membrane. These micromotors that use multiple fuel sources to power them offer a broader scope of preparation and show considerable promise for diverse applications of nanomotors in different chemical environments.Here, a chemical powered micromotor from the assembly of Au-SiO2 nanorods is presented. This new micromotor can be propelled efficiently by hydrogen bubbles generated from a hydrolysis reaction of aqueous NaBH4 and KBH4 and by oxygen bubbles produced by decomposition of H2O2. The monodisperse Au nanoparticles in mesoporous silica particles could catalyze the decomposition of two different kinds of fuels and produce bubbles. High speeds of 80 μm s-1 and recycles of more than 30 times are achieved in both NaBH4 and H2O2 media. Locomotion and rolling forms of movement were found. The locomotion forms can be obtained in a larger proportion by patterning the Au-SiO2 nanorods and a PDMS membrane. These micromotors that use multiple fuel sources to power them offer a broader scope of preparation and show considerable promise for diverse applications of nanomotors in different chemical environments. Electronic supplementary information (ESI) available: More electronic microscopy graphs, UV-Vis spectra and N2 adsorption isotherms. See DOI: 10.1039/c5nr02545a

  14. Ti nanorod arrays with a medium density significantly promote osteogenesis and osteointegration

    Ning, Chengyun; Wang, Shuangying; Zhu, Ye; Zhong, Meiling; Lin, Xi; Zhang, Yu; Tan, Guoxin; Li, Mei; Yin, Zhaoyi; Yu, Peng; Wang, Xiaolan; Li, Ying; He, Tianrui; Chen, Wei; Wang, Yingjun; Mao, Chuanbin

    2016-01-01

    Ti implants are good candidates in bone repair. However, how to promote bone formation on their surface and their consequent perfect integration with the surrounding tissue is still a challenge. To overcome such challenge, we propose to form Ti nanorods on their surface to promote the new bone formation around the implants. Here Ti nanorod arrays (TNrs) with different densities were produced on pure Ti surfaces using an anodizing method. The influence of TNr density on the protein adsorption as well as on the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 pre-osteoblastic cells were assessed. The TNrs were also implanted into the bone defects in rabbits to test their application in promoting bone formation and osteointegration at the implant-bone interface. TNrs with the medium density were found to show the best capability in promoting the protein adsorption from surrounding medium, which in turn efficiently enhanced osteogenic differentiation in vitro and osteointegration in vivo. Our work suggests that growing TNrs with a medium density on the surface of traditional Ti implants is an efficient and facile method for promoting bone formation and osteointegration in bone repair.

  15. Preparation of ZnO nanorods on conductive PET-ITO-Ag fibers

    Li, Yiwen; Ji, Shuai; Chen, Yuanyu; Zhang, Hong; Gong, Yumei; Guo, Jing

    2016-12-01

    We studied the vertical ZnO nanorods grown on conductive conventional polyethylene terephthalate (PET) fibers which are prepared by electroless silver depositing on tin-doped indium oxide (ITO) coated PET fibers through an efficient and low-cost green approach. The PET fibers were firstly functionalized with a layer of ITO gel synthesized through a sol-gel process at rather low temperature, simply by immersing the fibers into ITO sol for several minutes followed by gelation at 120 °C. Once the ITO gel layer surface was activated by SnCl2, a continuous, uniform, and compact layer of silver was carried out on the surface of the PET-ITO fibers through electroless plating operation at room temperature. The as-prepared PET-ITO-Ag fibers had good electrical conductivity, with surface resistivity as low as 0.23 mΩ cm. The overall procedure is simple, efficient, nontoxic, and controllable. The conductive PET-ITO-Ag fiber was used successfully as a flexible basal material to plant vertical ZnO nanorods through controlling the seeding and growth processes. The morphology of the PET-ITO, PET-ITO-Ag, and PET-ITO-Ag-ZnO fibers were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Undergone the whole process, although the tensile strength of the fiber decreased slightly, they may still exert their applications in flexible electronic such as photovoltaic and piezoelectric devices.

  16. Inactivation of bacterial biofilms using visible-light-activated unmodified ZnO nanorods

    Aponiene, Kristina; Serevičius, Tomas; Luksiene, Zivile; Juršėnas, Saulius

    2017-09-01

    Various zinc oxide (ZnO) nanostructures are widely used for photocatalytic antibacterial applications. Since ZnO possesses a wide bandgap, it is believed that only UV light may efficiently assist bacterial inactivation, and diverse crystal lattice modifications should be applied in order to narrow the bandgap for efficient visible-light absorption. In this work we show that even unmodified ZnO nanorods grown by an aqueous chemical growth technique are found to possess intrinsic defects that can be activated by visible light (λ = 405 nm) and successfully applied for total inactivation of various highly resistant bacterial biofilms rather than more sensitive planktonic bacteria. Time-resolved fluorescence analysis has revealed that visible-light excitation creates long-lived charge carriers (τ > 1 μs), which might be crucial for destructive biochemical reactions achieving significant bacterial biofilm inactivation. ZnO nanorods covered with bacterial biofilms of Enterococcus faecalis MSCL 302 after illumination by visible light (λ = 405 nm) were inactivated by 2 log, and Listeria monocytogenes ATCL3C 7644 and Escherichia coli O157:H7 biofilms by 4 log. Heterogenic waste-water microbial biofilms, consisting of a mixed population of mesophilic bacteria after illumination with visible light were also completely destroyed.

  17. Passivating ZnO Surface States by C60 Pyrrolidine Tris-Acid for Hybrid Solar Cells Based on Poly(3-hexylthiophene/ZnO Nanorod Arrays

    Peng Zhong

    2017-12-01

    Full Text Available Construction of ordered electron acceptors is a feasible way to solve the issue of phase separation in polymer solar cells by using vertically-aligned ZnO nanorod arrays (NRAs. However, the inert charge transfer between conducting polymer and ZnO limits the performance enhancement of this type of hybrid solar cells. In this work, a fullerene derivative named C60 pyrrolidine tris-acid is used to modify the interface of ZnO/poly(3-hexylthiophene (P3HT. Results indicate that the C60 modification passivates the surface defects of ZnO and improves its intrinsic fluorescence. The quenching efficiency of P3HT photoluminescence is enhanced upon C60 functionalization, suggesting a more efficient charge transfer occurs across the modified P3HT/ZnO interface. Furthermore, the fullerene modified hybrid solar cell based on P3HT/ZnO NRAs displays substantially-enhanced performance as compared to the unmodified one and the devices with other modifiers, which is contributed to retarded recombination and enhanced exciton separation as evidenced by electrochemical impedance spectra. Therefore, fullerene passivation is a promising method to ameliorate the connection between conjugated polymers and metal oxides, and is applicable in diverse areas, such as solar cells, transistors, and light-emitting dioxides.

  18. Higher photosynthesis, nutrient- and energy-use efficiencies contribute to invasiveness of exotic plants in a nutrient poor habitat in northeast China.

    Liu, Ming-Chao; Kong, De-Liang; Lu, Xiu-Rong; Huang, Kai; Wang, Shuo; Wang, Wei-Bin; Qu, Bo; Feng, Yu-Long

    2017-08-01

    The roles of photosynthesis-related traits in invasiveness of introduced plant species are still not well elucidated, especially in nutrient-poor habitats. In addition, little effort has been made to determine the physiological causes and consequences of the difference in these traits between invasive and native plants. To address these problems, we compared the differences in 16 leaf functional traits related to light-saturated photosynthetic rate (P max ) between 22 invasive and native plants in a nutrient-poor habitat in northeast China. The invasive plants had significantly higher P max , photosynthetic nitrogen- (PNUE), phosphorus- (PPUE), potassium- (PKUE) and energy-use efficiencies (PEUE) than the co-occurring natives, while leaf nutrient concentrations, construction cost (CC) and specific leaf area were not significantly different between the invasive and native plants. The higher PNUE contributed to higher P max for the invasive plants, which in turn contributed to higher PPUE, PKUE and PEUE. CC changed independently with other traits such as P max , PNUE, PPUE, PKUE and PEUE, showing two trait dimensions, which may facilitate acclimation to multifarious niche dimensions. Our results indicate that the invasive plants have a superior resource-use strategy, i.e. higher photosynthesis under similar resource investments, contributing to invasion success in the barren habitat. © 2017 Scandinavian Plant Physiology Society.

  19. Amorphous boron nanorod as an anode material for lithium-ion batteries at room temperature.

    Deng, Changjian; Lau, Miu Lun; Barkholtz, Heather M; Xu, Haiping; Parrish, Riley; Xu, Meiyue Olivia; Xu, Tao; Liu, Yuzi; Wang, Hao; Connell, Justin G; Smith, Kassiopeia A; Xiong, Hui

    2017-08-03

    We report an amorphous boron nanorod anode material for lithium-ion batteries prepared through smelting non-toxic boron oxide in liquid lithium. Boron in theory can provide capacity as high as 3099 mA h g -1 by alloying with Li to form B 4 Li 5 . However, experimental studies of the boron anode have been rarely reported for room temperature lithium-ion batteries. Among the reported studies the electrochemical activity and cycling performance of the bulk crystalline boron anode material are poor at room temperature. In this work, we utilized an amorphous nanostructured one-dimensional (1D) boron material aiming at improving the electrochemical reactivity between boron and lithium ions at room temperature. The amorphous boron nanorod anode exhibited, at room temperature, a reversible capacity of 170 mA h g -1 at a current rate of 10 mA g -1 between 0.01 and 2 V. The anode also demonstrated good rate capability and cycling stability. The lithium storage mechanism was investigated by both sweep voltammetry measurements and galvanostatic intermittent titration techniques (GITTs). The sweep voltammetric analysis suggested that the contributions from lithium ion diffusion into boron and the capacitive process to the overall lithium charge storage are 57% and 43%, respectively. The results from GITT indicated that the discharge capacity at higher potentials (>∼0.2 V vs. Li/Li + ) could be ascribed to a capacitive process and at lower potentials (ions and the amorphous boron nanorod. This work provides new insights into designing nanostructured boron materials for lithium-ion batteries.

  20. From covalent bonding to coalescence of metallic nanorods

    Lee Soohwan

    2011-01-01

    Full Text Available Abstract Growth of metallic nanorods by physical vapor deposition is a common practice, and the origin of their dimensions is a characteristic length scale that depends on the three-dimensional Ehrlich-Schwoebel (3D ES barrier. For most metals, the 3D ES barrier is large so the characteristic length scale is on the order of 200 nm. Using density functional theory-based ab initio calculations, this paper reports that the 3D ES barrier of Al is small, making it infeasible to grow Al nanorods. By analyzing electron density distributions, this paper shows that the small barrier is the result of covalent bonding in Al. Beyond the infeasibility of growing Al nanorods by physical vapor deposition, the results of this paper suggest a new mechanism of controlling the 3D ES barrier and thereby nanorod growth. The modification of local degree of covalent bonding, for example, via the introduction of surfactants, can increase the 3D ES barrier and promote nanorod growth, or decrease the 3D ES barrier and promote thin film growth.

  1. Highly Uniform Epitaxial ZnO Nanorod Arrays for Nanopiezotronics

    Nagata T

    2009-01-01

    Full Text Available Abstract Highly uniform and c-axis-aligned ZnO nanorod arrays were fabricated in predefined patterns by a low temperature homoepitaxial aqueous chemical method. The nucleation seed patterns were realized in polymer and in metal thin films, resulting in, all-ZnO and bottom-contacted structures, respectively. Both of them show excellent geometrical uniformity: the cross-sectional uniformity according to the scanning electron micrographs across the array is lower than 2%. The diameter of the hexagonal prism-shaped nanorods can be set in the range of 90–170 nm while their typical length achievable is 0.5–2.3 μm. The effect of the surface polarity was also examined, however, no significant difference was found between the arrays grown on Zn-terminated and on O-terminated face of the ZnO single crystal. The transmission electron microscopy observation revealed the single crystalline nature of the nanorods. The current–voltage characteristics taken on an individual nanorod contacted by a Au-coated atomic force microscope tip reflected Schottky-type behavior. The geometrical uniformity, the designable pattern, and the electrical properties make the presented nanorod arrays ideal candidates to be used in ZnO-based DC nanogenerator and in next-generation integrated piezoelectric nano-electromechanical systems (NEMS.

  2. Nanorods of manganese oxides: Synthesis, characterization and catalytic application

    Yang, Zeheng; Zhang, Yuancheng; Zhang, Weixin; Wang, Xue; Qian, Yitai; Wen, Xiaogang; Yang, Shihe

    2006-03-01

    Single-crystalline nanorods of β-MnO 2, α-Mn 2O 3 and Mn 3O 4 were successfully synthesized via the heat-treatment of γ-MnOOH nanorods, which were prepared through a hydrothermal method in advance. The calcination process of γ-MnOOH nanorods was studied with the help of Thermogravimetric analysis and X-ray powder diffraction. When the calcinations were conducted in air from 250 to 1050 °C, the precursor γ-MnOOH was first changed to β-MnO 2, then to α-Mn 2O 3 and finally to Mn 3O 4. When calcined in N 2 atmosphere, γ-MnOOH was directly converted into Mn 3O 4 at as low as 500 °C. Transmission electron microscopy (TEM) and high-resolution TEM were also used to characterize the products. The obtained manganese oxides maintain the one-dimensional morphology similar to the precursor γ-MnOOH nanorods. Further experiments show that the as-prepared manganese oxide nanorods have catalytic effect on the oxidation and decomposition of the methylene blue (MB) dye with H 2O 2.

  3. Vapour transport growth of ZnO nanorods

    Mofor, A.C.; Bakin, A.S.; Elshaer, A.; Waag, A. [Technical University Braunschweig, Institute of Semiconductor Technology, Braunschweig (Germany); Fuhrmann, D.; Hangleiter, A. [Technical University Braunschweig, Institute of Applied Physics, Braunschweig (Germany); Bertram, F.; Christen, J. [University of Magdeburg, Department of Solid State Physics, Magdeburg (Germany)

    2007-07-15

    The fabrication of low-dimensional ZnO structures has attracted enormous attention as such nanostructures are expected to pave the way for many interesting applications in optoelectronics, spin electronics gas sensor technology and biomedicine. Many reported fabrication methods, especially for ZnO nanorods are mostly based on catalyst-assisted growth techniques that employ metal-organic sources and other contaminating agents like graphite to grow ZnO nanorods at relatively high temperatures. We report on catalyst-free vapour-phase epitaxy growth of ZnO nanorods on 6H-SiC and (11-20)Al{sub 2}O{sub 3} using purely elemental sources at relatively low temperatures and growth pressure. ZnO nanorods with widths of 80-900 nm and lengths of up to 12 {mu}m were obtained. Nanorod density on the order of 10{sup 9} cm{sup -2} with homogenous luminescence and high purity was also noted. (orig.)

  4. Effects of Chromium Dopant on Ultraviolet Photoresponsivity of ZnO Nanorods

    Mokhtari, S.; Safa, S.; Khayatian, A.; Azimirad, R.

    2017-07-01

    Structural and optical properties of bare ZnO nanorods, ZnO-encapsulated ZnO nanorods, and Cr-doped ZnO-encapsulated ZnO nanorods have been investigated. Encapsulated ZnO nanorods were grown using a simple two-stage method in which ZnO nanorods were first grown on a glass substrate directly from a hydrothermal bath, then encapsulated with a thin layer of Cr-doped ZnO by dip coating. Comparative study of x-ray diffraction patterns showed that Cr was successfully incorporated into the shell layer of ZnO nanorods. Moreover, energy-dispersive x-ray spectroscopy confirmed presence of Cr in this sample. It was observed that the thickness of the shell layer around the core of the ZnO nanorods was at least about 20 nm. Transmission electron microscopy of bare ZnO nanorods revealed single-crystalline structure. Based on optical results, both the encapsulation process and addition of Cr dopant decreased the optical bandgap of the samples. Indeed, the optical bandgap values of Cr-doped ZnO-encapsulated ZnO nanorods, ZnO-encapsulated ZnO nanorods, and bare ZnO nanorods were 2.89 eV, 3.15 eV, and 3.34 eV, respectively. The ultraviolet (UV) parameters demonstrated that incorporation of Cr dopant into the shell layer of ZnO nanorods considerably facilitated formation and transportation of photogenerated carriers, optimizing their performance as a practical UV detector. As a result, the photocurrent of the Cr-doped ZnO-encapsulated ZnO nanorods was the highest (0.6 mA), compared with ZnO-encapsulated ZnO nanorods and bare ZnO nanorods (0.21 mA and 0.06 mA, respectively).

  5. ZnO nanorod arrays grown under different pressures and their photoluminescence properties

    Meng Xiuqing [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic ZoneChangchun 130033 (China); Graduate School of the Chinese Academy of Sciences (China); Zhao Dongxu [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic ZoneChangchun 130033 (China)]. E-mail: dxzhao2000@yahoo.com.cn; Shen Dezhen [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic ZoneChangchun 130033 (China); Zhang Jiying [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic ZoneChangchun 130033 (China); Li Binghui [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic ZoneChangchun 130033 (China); Wang Xiaohua [National Key Laboratory of High Power Semiconductor Laser, Changchun University of Science and technology, 7089 Weixing Road Changchun (China); Fan Xiwu [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic ZoneChangchun 130033 (China)

    2007-01-15

    The ZnO nanorod arrays were synthesized via a simple vapor deposition method on Si (1 1 1) substrates at a low growth temperature of 520 deg. C. By selecting different source materials under different growth pressures, well-aligned hexagonal-shaped ZnO nanorod arrays were obtained under both conditions. X-ray diffraction (XRD) analysis confirmed the nanorods are c-axis orientated. Selected area electron diffraction (SAED) and transmission electron microscopy (TEM) analysis demonstrated the individual nanorod is single crystal. Photoluminescence (PL) analyses show the superior optical properties of the nanorod arrays.

  6. ZnO nanorod arrays grown under different pressures and their photoluminescence properties

    Meng Xiuqing; Zhao Dongxu; Shen Dezhen; Zhang Jiying; Li Binghui; Wang Xiaohua; Fan Xiwu

    2007-01-01

    The ZnO nanorod arrays were synthesized via a simple vapor deposition method on Si (1 1 1) substrates at a low growth temperature of 520 deg. C. By selecting different source materials under different growth pressures, well-aligned hexagonal-shaped ZnO nanorod arrays were obtained under both conditions. X-ray diffraction (XRD) analysis confirmed the nanorods are c-axis orientated. Selected area electron diffraction (SAED) and transmission electron microscopy (TEM) analysis demonstrated the individual nanorod is single crystal. Photoluminescence (PL) analyses show the superior optical properties of the nanorod arrays

  7. ZnO nanorod array solid phase micro-extraction fiber coating: fabrication and extraction capability

    Wang Dan; Zhang Zhuomin; Li Tiemei; Zhang Lan; Chen Guonan; Luo Lin

    2009-01-01

    In this paper, a ZnO nanorod array has been introduced as a coating to the headspace solid phase micro-extraction (HSSPME) field. The coating shows good extraction capability for volatile organic compounds (VOCs) by use of BTEX as a standard and can be considered suitable for sampling trace and small molecular VOC targets. In comparison with the randomly oriented ZnO nanorod HSSPME coating, ZnO nanorod array HSSPME fiber coating shows better extraction capability, which is attributed to the nanorod array structure of the coating. Also, this novel nanorod array coating shows good extraction selectivity to 1-propanethiol.

  8. Influence of the contacting scheme in simulations of radial silicon nanorod solar cells

    Voigt, Felix; Stelzner, Thomas; Christiansen, Silke H.

    2012-01-01

    Silicon nanorod solar cells were simulated using the Silvaco Technical Computer Aided Design (TCAD) software suite. For reasons of speed optimization the simulations were performed in cylinder coordinates taking advantage of the model's symmetry. Symmetric doping was assumed with a dopant density of 10 18 cm −3 in the p-type core and in the n-type shell, and the location of the pn-junction was chosen such that the space charge region was located adjacent to the shell surface. Two contact configurations were explored. In configuration A the cathode contact was wrapped around the semiconductor nanorod, while in configuration B the cathode was assumed just on top of the nanorod. In both cases the anode was located at the bottom of the rod. Cell efficiency was optimized with regard to rod radius and rod length. Optimization was performed in a three-step procedure consisting in radius optimization, length optimization and again radius optimization. A maximum in efficiency with respect to rod length L was visible in configuration A, leading to an optimum value of L = 48 μm. This maximum is explained by the combination of an increase of short-circuit current density J sc and a decrease of open-circuit voltage U oc with L. In configuration B, J sc also increases with L, but U oc stays rather constant and the maximum in efficiency only appears at very large values of L ≈ 12 mm. We restricted the rod length to L ≤ 100 μm for further optimization, in order to stay in an experimentally feasible range. During the optimization of rod radius R in configuration A the open circuit voltage increased continuously, while short circuit current density stayed rather constant. This leads to an increase in efficiency with R, which only stops at very large radii, where R starts to be comparable with L. In configuration B efficiency is almost independent of R, provided that the radius is large enough to comprise a well-formed space charge region, here only a shallow maximum can be

  9. Influence of the contacting scheme in simulations of radial silicon nanorod solar cells

    Voigt, Felix, E-mail: felix.voigt@uni-oldenburg.de [Institute of Photonic Technology, Jena (Germany); Institute of Physics, University of Oldenburg (Germany); Stelzner, Thomas [Institute of Photonic Technology, Jena (Germany); Christiansen, Silke H. [Institute of Photonic Technology, Jena (Germany); Max Planck Institute for the Science of Light, Erlangen (Germany)

    2012-10-01

    Silicon nanorod solar cells were simulated using the Silvaco Technical Computer Aided Design (TCAD) software suite. For reasons of speed optimization the simulations were performed in cylinder coordinates taking advantage of the model's symmetry. Symmetric doping was assumed with a dopant density of 10{sup 18} cm{sup -3} in the p-type core and in the n-type shell, and the location of the pn-junction was chosen such that the space charge region was located adjacent to the shell surface. Two contact configurations were explored. In configuration A the cathode contact was wrapped around the semiconductor nanorod, while in configuration B the cathode was assumed just on top of the nanorod. In both cases the anode was located at the bottom of the rod. Cell efficiency was optimized with regard to rod radius and rod length. Optimization was performed in a three-step procedure consisting in radius optimization, length optimization and again radius optimization. A maximum in efficiency with respect to rod length L was visible in configuration A, leading to an optimum value of L = 48 {mu}m. This maximum is explained by the combination of an increase of short-circuit current density J{sub sc} and a decrease of open-circuit voltage U{sub oc} with L. In configuration B, J{sub sc} also increases with L, but U{sub oc} stays rather constant and the maximum in efficiency only appears at very large values of L Almost-Equal-To 12 mm. We restricted the rod length to L {<=} 100 {mu}m for further optimization, in order to stay in an experimentally feasible range. During the optimization of rod radius R in configuration A the open circuit voltage increased continuously, while short circuit current density stayed rather constant. This leads to an increase in efficiency with R, which only stops at very large radii, where R starts to be comparable with L. In configuration B efficiency is almost independent of R, provided that the radius is large enough to comprise a well-formed space

  10. Annealing Effect on Photovoltaic Performance of CdSe Quantum-Dots-Sensitized TiO2 Nanorod Solar Cells

    Yitan Li

    2012-01-01

    Full Text Available Large area rutile TiO2 nanorod arrays were grown on F:SnO2 (FTO conductive glass using a hydrothermal method at low temperature. CdSe quantum dots (QDs were deposited onto single-crystalline TiO2 nanorod arrays by a chemical bath deposition (CBD method to make a photoelectrode. The solar cell was assembled using a CdSe-TiO2 nanostructure as the photoanode and polysulfide solution as the electrolyte. The annealing effect on optical and photovoltaic properties of CdSe quantum-dots-sensitized TiO2 nanorod solar cells was studied systematically. A significant change of the morphology and a regular red shift of band gap of CdSe nanoparticles were observed after annealing treatment. At the same time, an improved photovoltaic performance was obtained for quantum-dots-sensitized solar cell using the annealed CdSe-TiO2 nanostructure electrode. The power conversion efficiency improved from 0.59% to 1.45% as a consequence of the annealing effect. This improvement can be explained by considering the changes in the morphology, the crystalline quality, and the optical properties caused by annealing treatment.

  11. Tin Oxide Nanorod Array-Based Electrochemical Hydrogen Peroxide Biosensor

    Liu Jinping

    2010-01-01

    Full Text Available Abstract SnO2 nanorod array grown directly on alloy substrate has been employed as the working electrode of H2O2 biosensor. Single-crystalline SnO2 nanorods provide not only low isoelectric point and enough void spaces for facile horseradish peroxidase (HRP immobilization but also numerous conductive channels for electron transport to and from current collector; thus, leading to direct electrochemistry of HRP. The nanorod array-based biosensor demonstrates high H2O2 sensing performance in terms of excellent sensitivity (379 μA mM−1 cm−2, low detection limit (0.2 μM and high selectivity with the apparent Michaelis–Menten constant estimated to be as small as 33.9 μM. Our work further demonstrates the advantages of ordered array architecture in electrochemical device application and sheds light on the construction of other high-performance enzymatic biosensors.

  12. Metallic nickel nanorod arrays embedded into ordered block copolymer templates

    Seifarth, O.; Krenek, R.; Tokarev, I.; Burkov, Y.; Sidorenko, A.; Minko, S.; Stamm, M.; Schmeisser, D.

    2007-01-01

    We report on metallic Nickel nanorods prepared by utilizing a mask of ordered nanostructured hollow channels in a block copolymer matrix. These polymeric templates were formed by a self organized process in block copolymer supramolecular assemblies. Nickel was filled into with two different techniques, electrodeposition and washing in. We monitor the formation process of these nanorods by means of atomic force microscopy and synchrotron radiation soft X-ray based photoelectron emission microscopy. The oxidation state of the nickelrods is evaluated with X-ray absorption spectroscopy and X-ray photoelectron spectroscopy at the Ni L edges and lateral distributions of the Ni nanorods were detected with micrometer resolved X-ray absorption spectroscopy. The finding is that the Ni rods were metallic despite their preparation under ambient conditions, inside the particles no hints for NiO complexes were found. This indicates that the polymer protects Ni nanoparticles against oxidation

  13. Fabrication and Photocatalytic Properties of ZnSe Nanorod Films

    Jiajia Yin

    2016-01-01

    Full Text Available ZnSe nanorod films grown on fused quartz glass substrates via a simple two-step synthesis protocol were demonstrated to be environmentally safe and effective recyclable photocatalysts. These films showed greatly enhanced photocatalytic activity compared to pulsed laser deposition ZnSe films in the degradation of methyl orange dye solutions. The well-crystalized ZnSe nanorods had a length of 15 µm and a diameter of 200 nm and were densely grown on the substrate. The morphology, crystal structure, crystal phase, and photophysical properties of the ZnSe nanorod films were investigated using field-emission scanning electron microscopy (FE-SEM, UV-Vis spectroscopy, X-ray diffraction (XRD, transmission electron microscopy (TEM, and high resolution transmission electron microscopy (HRTEM.

  14. Cr2O3 nanoparticle-functionalized WO3 nanorods for ethanol gas sensors

    Choi, Seungbok; Bonyani, Maryam; Sun, Gun-Joo; Lee, Jae Kyung; Hyun, Soong Keun; Lee, Chongmu

    2018-02-01

    Pristine WO3 nanorods and Cr2O3-functionalized WO3 nanorods were synthesized by the thermal evaporation of WO3 powder in an oxidizing atmosphere, followed by spin-coating of the nanowires with Cr2O3 nanoparticles and thermal annealing in an oxidizing atmosphere. Scanning electron microscopy was used to examine the morphological features and X-ray diffraction was used to study the crystallinity and phase formation of the synthesized nanorods. Gas sensing tests were performed at different temperatures in the presence of test gases (ethanol, acetone, CO, benzene and toluene). The Cr2O3-functionalized WO3 nanorods sensor showed a stronger response to these gases relative to the pristine WO3 nanorod sensor. In particular, the response of the Cr2O3-functionalized WO3 nanorods sensor to 200 ppm ethanol gas was 5.58, which is approximately 4.4 times higher that of the pristine WO3 nanorods sensor. Furthermore, the Cr2O3-functionalized WO3 nanorods sensor had a shorter response and recovery time. The pristine WO3 nanorods had no selectivity toward ethanol gas, whereas the Cr2O3-functionalized WO3 nanorods sensor showed good selectivity toward ethanol. The gas sensing mechanism of the Cr2O3-functionalized WO3 nanorods sensor toward ethanol is discussed in detail.

  15. Surface stabilized GMR nanorods of silver coated CrO2 synthesized via a polymer complex at ambient pressure

    Biswas, S.; Singh, G.P.; Ram, S.; Fecht, H.-J.

    2013-01-01

    Stable anisotropic nanorods of surface modified CrO 2 (∼18 nm diameter) with a correlated diamagnetic layer (2–3 nm thickness) of silver efficiently tailors useful magnetic and magnetoresistance (MR) properties. Essentially, it involves a core-shell structure that is developed by displacing part of Cr 4+ ions by Ag atoms on the CrO 2 surface (topotactic surface layer) via an etching reaction of a CrO 2 -polymer complex with Ag + ions in hot water followed by heating the dried sample at 300–400 °C in air. The stable Ag-layer so obtained in the form of a shell protects CrO 2 such that it no longer converts to Cr 2 O 3 in ambient pressure during the processing. X-ray diffractogram of the Rutile type tetragonal CrO 2 structure (lattice parameters a=0.4429 nm and c=0.2950 nm) includes weak peaks of a minority phase of an fcc-Ag (a=0.4086 nm). The silver surface layer, which manifests itself in a doublet of the 3d 5/2 and 3d 3/2 X-ray photoelectron bands of binding energies 368.46 eV and 374.48 eV, respectively, suppresses almost all Cr bands to appear in a measurable intensity. The sample exhibits a distinctly enhanced MR-value, e.g., (−) 7.6% at 77 K, than reported values in compacted CrO 2 powders or composites. Such a large MR-value in the Coulomb blockade regime ( 2 nanorods. - Highlights: • Synthesis and structural studies of a novel GMR material of Ag coated CrO 2 . • Tailoring useful GMR property in CrO 2 nanorods of controlled shape and anisotropy. • Enhanced GMR is explained in correlation to the surface structure of CrO 2 nanorods

  16. Synthesis of binary bismuth-cadmium oxide nanorods with sensitive electrochemical sensing performance

    Wen, Yong; Pei, Lizhai; Wei, Tian

    2017-01-01

    Binary bismuth-cadmium oxide nanorods have been synthesized by a simple hydrothermal process without templates and additives. X-ray diffraction and high-resolution transmission electron microscopy reveal that the nanorods possess single crystalline tetragonal Bi 2 CdO 4 phase. Scanning electron microscopy and transmission electron microscopy images show that the length and diameter of the nanorods are 20-300 nm and 5-10 μm, respectively. The formation of the binary bismuth-cadmium oxide nanorods is closely related to the hydrothermal parameters. The electrochemical sensing performance of the binary bismuth-cadmium oxide nanorods has been investigated using the nanorods as glassy carbon electrode modifiers. The detection limit is 0.19 μM with a linear range of 0.0005-2 mM. The nanorod-modified glassy carbon electrode exhibits good electrocatalytic activity toward L-cysteine and great application potential for electrochemical sensors.

  17. Synthesis of binary bismuth-cadmium oxide nanorods with sensitive electrochemical sensing performance

    Wen, Yong [Xinjiang Univ., Xinjiang (China). School of Civil Engineering and Architecture; Pei, Lizhai; Wei, Tian [Anhui Univ. of Technology, Anhui (China). School of Materials Science and Engineering

    2017-07-15

    Binary bismuth-cadmium oxide nanorods have been synthesized by a simple hydrothermal process without templates and additives. X-ray diffraction and high-resolution transmission electron microscopy reveal that the nanorods possess single crystalline tetragonal Bi{sub 2}CdO{sub 4} phase. Scanning electron microscopy and transmission electron microscopy images show that the length and diameter of the nanorods are 20-300 nm and 5-10 μm, respectively. The formation of the binary bismuth-cadmium oxide nanorods is closely related to the hydrothermal parameters. The electrochemical sensing performance of the binary bismuth-cadmium oxide nanorods has been investigated using the nanorods as glassy carbon electrode modifiers. The detection limit is 0.19 μM with a linear range of 0.0005-2 mM. The nanorod-modified glassy carbon electrode exhibits good electrocatalytic activity toward L-cysteine and great application potential for electrochemical sensors.

  18. Growth of aragonite calcium carbonate nanorods in the biomimetic anodic aluminum oxide template

    Lee, Inho; Han, Haksoo; Lee, Sang-Yup

    2010-04-01

    In this study, a biomimetic template was prepared and applied for growing calcium carbonate (CaCO 3) nanorods whose shape and polymorphism were controlled. A biomimetic template was prepared by adsorbing catalytic dipeptides into the pores of an anodic aluminum oxide (AAO) membrane. Using this peptide-adsorbed template, mineralization and aggregation of CaCO 3 was carried out to form large nanorods in the pores. The nanorods were aragonite and had a structure similar to nanoneedle assembly. This aragonite nanorod formation was driven by both the AAO template and catalytic function of dipeptides. The AAO membrane pores promoted generation of aragonite polymorph and guided nanorod formation by guiding the nanorod growth. The catalytic dipeptides promoted the aggregation and further dehydration of calcium species to form large nanorods. Functions of the AAO template and catalytic dipeptides were verified through several control experiments. This biomimetic approach makes possible the production of functional inorganic materials with controlled shapes and crystalline structures.

  19. Photoluminescence and lasing properties of ZnO nanorods

    Lee, Geon Joon; Lee, Young Pak; Min, Sun Ki; Han, Sung Hwan; Lim, Hwan Hong; Cha, Myoung Sik; Kim, Sung Soo; Cheong, Hyeon Sik

    2010-01-01

    In this study, we investigated the structures, photoluminescence (PL), and lasing characteristics of the ZnO nanorods prepared by using chemical bath deposition. The continuous-wave HeCd laser excited PL spectra of the ZnO nanorods exhibited two emission bands, one in the UV region and the other in the visible region. The UV emission band has its peak at 3.25 eV with a bandwidth of 160 meV. However, the PL spectra under 355-nm, 35-ps pulse excitation exhibited a spectrally-narrowed UV emission band with a peak at 3.20 eV and a spectral width of 35 meV. The lasing phenomena were ascribed to the amplified spontaneous emission (ASE) caused by coupling of the microcavity effect of ZnO nanorods and the high-intensity excitation. Above the lasing threshold, the ASE peak intensity exhibited a superlinear dependence on the excitation intensity. For an excitation pulse energy of 3 mJ, the ASE peak intensity was increased by enlarging the length of the ZnO nanorods from 1 μm to 4 μm. In addition, the PL spectrum under 800-nm femtosecond pulse excitation exhibited second harmonic generation, as well as the multiphoton absorption-induced UV emission band. In this research, ZnO nanorods were grown on seed layers by using chemical bath deposition in an aqueous solution of Zn(NO 3 ) 2 and hexamethyltetramine. The seed layers were prepared on conducting glass substrates by dip coating in an aqueous colloidal dispersion containing 50% 70-nm ZnO nanoparticles. Scanning electron microscopy clearly revealed that ZnO nanorods were successfully grown on the seed layers.

  20. In-Doped ZnO Hexagonal Stepped Nanorods and Nanodisks as Potential Scaffold for Highly-Sensitive Phenyl Hydrazine Chemical Sensors.

    Umar, Ahmad; Kim, Sang Hoon; Kumar, Rajesh; Al-Assiri, Mohammad S; Al-Salami, A E; Ibrahim, Ahmed A; Baskoutas, Sotirios

    2017-11-21

    Herein, we report the growth of In-doped ZnO (IZO) nanomaterials, i.e., stepped hexagonal nanorods and nanodisks by the thermal evaporation process using metallic zinc and indium powders in the presence of oxygen. The as-grown IZO nanomaterials were investigated by several techniques in order to examine their morphological, structural, compositional and optical properties. The detailed investigations confirmed that the grown nanomaterials, i.e., nanorods and nanodisks possess well-crystallinity with wurtzite hexagonal phase and grown in high density. The room-temperature PL spectra exhibited a suppressed UV emissions with strong green emissions for both In-doped ZnO nanomaterials, i.e., nanorods and nanodisks. From an application point of view, the grown IZO nanomaterials were used as a potential scaffold to fabricate sensitive phenyl hydrazine chemical sensors based on the I-V technique. The observed sensitivities of the fabricated sensors based on IZO nanorods and nanodisks were 70.43 μA·mM -1 cm -2 and 130.18 μA·mM -1 cm -2 , respectively. For both the fabricated sensors, the experimental detection limit was 0.5 μM, while the linear range was 0.5 μM-5.0 mM. The observed results revealed that the simply grown IZO nanomaterials could efficiently be used to fabricate highly sensitive chemical sensors.

  1. Enhancement of ZnO nanorod arrays-based inverted type hybrid organic solar cell using spin-coated Eosin-Y

    Lim, Eng Liang; Yap, Chi Chin; Yahaya, Muhammad; Salleh, Muhamad Mat

    2013-01-01

    This paper reports the effect of Eosin-Y coating concentration on the performance of inverted type hybrid organic solar cell based on ZnO nanorod arrays and poly(3-hexylthiophene-2,5-diyl) (P3HT). The Eosin-Y solution with concentrations of 0.05, 0.2, 2.0 and 5.0 mM was spin-coated onto the ZnO nanorod arrays grown on the fluorine-doped tin oxide glass substrate. The P3HT film was then spin-coated onto Eosin-Y-coated ZnO nanorod arrays, followed by deposition of silver (Ag) as anode using magnetron sputtering technique. The short circuit current density increased with the Eosin-Y coating concentration up to 0.2 mM, after which it started to decrease, mainly due to the aggregation of Eosin-Y which reduced the charge extraction from P3HT to ZnO. Meanwhile, the open circuit voltage increased with the Eosin-Y coating concentration, indicating reduced back charge recombination of electron on the ZnO and hole on the P3HT, as well as reduced leakage current through the direct contact between the ZnO nanorods and the Ag metal contact. The power conversion efficiency of the device with the optimum coating concentration was approximately eight times higher than that without Eosin-Y modification. (paper)

  2. Enhancement of ZnO nanorod arrays-based inverted type hybrid organic solar cell using spin-coated Eosin-Y

    Lim, Eng Liang; Yap, Chi Chin; Yahaya, Muhammad; Mat Salleh, Muhamad

    2013-04-01

    This paper reports the effect of Eosin-Y coating concentration on the performance of inverted type hybrid organic solar cell based on ZnO nanorod arrays and poly(3-hexylthiophene-2,5-diyl) (P3HT). The Eosin-Y solution with concentrations of 0.05, 0.2, 2.0 and 5.0 mM was spin-coated onto the ZnO nanorod arrays grown on the fluorine-doped tin oxide glass substrate. The P3HT film was then spin-coated onto Eosin-Y-coated ZnO nanorod arrays, followed by deposition of silver (Ag) as anode using magnetron sputtering technique. The short circuit current density increased with the Eosin-Y coating concentration up to 0.2 mM, after which it started to decrease, mainly due to the aggregation of Eosin-Y which reduced the charge extraction from P3HT to ZnO. Meanwhile, the open circuit voltage increased with the Eosin-Y coating concentration, indicating reduced back charge recombination of electron on the ZnO and hole on the P3HT, as well as reduced leakage current through the direct contact between the ZnO nanorods and the Ag metal contact. The power conversion efficiency of the device with the optimum coating concentration was approximately eight times higher than that without Eosin-Y modification.

  3. Towards nanorod LEDs: Numerical predictions and controlled growth

    Koelper, Christopher [Osram Opto Semiconductors GmbH, Leibnizstr. 4, 93055 Regensburg (Germany); Computational Electronics and Photonics, Universitaet Kassel, Wilhelmshoeher Allee 71, 34121 Kassel (Germany); Bergbauer, Werner [Osram Opto Semiconductors GmbH, Leibnizstr. 4, 93055 Regensburg (Germany); Institut fuer Halbleitertechnik, TU Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Drechsel, Philipp; Sabathil, Matthias; Strassburg, Martin; Lugauer, Hans-Juergen [Osram Opto Semiconductors GmbH, Leibnizstr. 4, 93055 Regensburg (Germany); Witzigmann, Bernd [Computational Electronics and Photonics, Universitaet Kassel, Wilhelmshoeher Allee 71, 34121 Kassel (Germany); Fuendling, Soenke; Li, Shunfeng; Wehmann, Hergo-Heinrich; Waag, Andreas [Institut fuer Halbleitertechnik, TU Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany)

    2011-07-15

    We present a numerical optimization of nanorod geometries with respect to the optical properties of an electrically driven LED emitting in the green spectral range. It is shown that an overall Purcell enhancement as well as directional emission can be achieved at an emission wavelength of 550 nm with nanorods of 110 nm radius. Position-controlled growth on patterned substrates demonstrates that the required dimensions are accessible by varying growth parameters and growth time in a large volume MOVPE reactor. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Properties of V-implanted ZnO nanorods

    Schlenker, E [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Bakin, A [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Schmid, H [Institut fuer Anorganische Chemie, University of Bonn, Roemerstrasse 164, 53117 Bonn (Germany); Mader, W [Institut fuer Anorganische Chemie, University of Bonn, Roemerstrasse 164, 53117 Bonn (Germany); Sievers, S [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany); Albrecht, M [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany); Ronning, C [II. Institute of Physics, Georg-August-University Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Mueller, S [II. Institute of Physics, Georg-August-University Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Al-Suleiman, M [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Postels, B [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Wehmann, H-H [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Siegner, U [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany); Waag, A [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany)

    2007-03-28

    ZnO nanorods were grown on Si substrates by an aqueous chemical approach and subsequently doped by V implantation. Transmission electron microscopy and photoluminescence spectroscopy reveal a severely defective material directly after the implantation process. Subsequent annealing leads to a partial recovery of the crystal structure. The magnetic features of ZnO:V nanorods were investigated by magnetic force microscopy. Images taken of ensembles as well as of single rods clearly display contrast, which is seen as a strong indication of ferromagnetism at room temperature.

  5. Spontaneous Superlattice Formation in Nanorods through PartialCation Exchange

    Robinson, Richard D.; Sadtler, Bryce; Demchenko, Denis O.; Erdonmez, Can K.; Wang, Lin-Wang; Alivisatos, A. Paul

    2007-03-14

    Lattice mismatch strains are widely known to controlnanoscale pattern formation in heteroepitaxy, but such effects have notbeen exploited in colloidal nanocrystal growth. We demonstrate acolloidal route to synthesizing CdS-Ag2S nanorod superlattices throughpartial cation exchange. Strain induces the spontaneous formation ofperiodic structures. Ab initio calculations of the interfacial energy andmodeling of strain energies show that these forces drive theself-organization. The nanorod superlattices exhibit high stabilityagainst ripening and phase mixing. These materials are tunablenear-infrared emitters with potential applications as nanometer-scaleoptoelectronic devices.

  6. Preparation of single-crystal copper ferrite nanorods and nanodisks

    Du Jimin; Liu Zhimin; Wu Weize; Li Zhonghao; Han Buxing; Huang Ying

    2005-01-01

    This article, for the first time, reports the preparation of single-crystal copper ferrite nanorods and nanodisks. Using amorphous copper ferrite nanoparticles synthesized by reverse micelle as reaction precursor, single-crystal copper ferrite nanorods were synthesized via hydrothermal method in the presence of surfactant polyethylene glycol (PEG), however, copper ferrite nanodisks were prepared through the same procedures except the surfactant PEG. The resulting nanomaterials have been characterized by powder X-ray diffraction (XRD), selected electron area diffraction (SEAD), and transmission electron microscopy (TEM). The bulk composition of the samples was determined by means of X-ray photoelectron spectroscopy (XPS)

  7. Interstitial diffuse radiance spectroscopy of gold nanocages and nanorods in bulk muscle tissues.

    Grabtchak, Serge; Montgomery, Logan G; Pang, Bo; Wang, Yi; Zhang, Chao; Li, Zhiyuan; Xia, Younan; Whelan, William M

    2015-01-01

    Radiance spectroscopy was applied to the interstitial detection of localized inclusions containing Au nanocages or nanorods with various concentrations embedded in porcine muscle phantoms. The radiance was quantified using a perturbation approach, which enabled the separation of contributions from the porcine phantom and the localized inclusion, with the inclusion serving as a perturbation probe of photon distributions in the turbid medium. Positioning the inclusion at various places in the phantom allowed for tracking of photons that originated from a light source, passed through the inclusion's location, and reached a detector. The inclusions with high extinction coefficients were able to absorb nearly all photons in the range of 650-900 nm, leading to a spectrally flat radiance signal. This signal could be converted to the relative density of photons incident on the inclusion. Finally, the experimentally measured quantities were expressed via the relative perturbation and arranged into the classical Beer-Lambert law that allowed one to extract the extinction coefficients of various types of Au nanoparticles in both the transmission and back reflection geometries. It was shown that the spatial variation of perturbation could be described as 1/r dependence, where r is the distance between the inclusion and the detector. Due to a larger absorption cross section, Au nanocages produced greater perturbations than Au nanorods of equal particle concentration, indicating a better suitability of Au nanocages as contrast agents for optical measurements in turbid media. Individual measurements from different inclusions were combined into detectability maps.

  8. Synthesis, characterization, and photocatalytic activities of Cobalt(II)-Titanium dioxide nanorods, and electrophoretic deposition of Titanium dioxide nanoparticle/nanorod composite films for self-cleaning applications

    Kang, Wonjun

    This dissertation consists of two projects. The first project is synthesis, characterization, and photocatalytic activities of Co(II)-TiO2 nanorods. We modified brookite TiO2 nanorods with cobalt(II) ions to design new photocatalysts with visible light absorption. X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) data indicated that the local structure of Co(II)-TiO2 nanorods was shown as tetrahedral and octahedral Co(II) sites at TiO2 nanorod surface. Dimethylglyoxime (DMG) has been used to remove surface Co(II) from Co(II)-TiO2 nanorods to determine single-site Co(II) ions selectively attached to the TiO 2 nanorod surface. We proposed a mechanism that the Co-Co bond of the precursor Co2(CO)8 undergoes heterolysis followed by disproportionation of Co(I) to produce Co(II) and Co(0) precipitate. Finally, the Co(II)-TiO2 nanorods showed greater activity than TiO 2 nanorods in the degradation of 5,8-dihydroxy-1,4-naphthoquinone (DHNQ) dye under visible light irradiation. The second project is electrophoretic deposition (EPD) of TiO2 nanoparticle/nanorod composite films for self-cleaning applications. We developed novel electrolyte system for EPD of TiO2 nanoparticle/nanorod composites for self-cleaning coatings. A mixture of TiO2 powder and TiO2 nanorods was used as EPD suspension in a mixture of THF and acetone. TiO2 nanoparticle/nanorod composite films were fabricated on aluminium substrates via the EPD method, and were characterized by scanning electron microscope (SEM). SEM images showed that TiO2 nanoparticle/nanorod composite films had a uniform pore structure. The hydrophobic properties of surfaces in TiO2 nanoparticle/nanorod composite films were evaluated by water contact angle measurements. It was found that the surfaces of TiO2 nanoparticle/nanorod composite films were hydrophobic with contact angle of 103°. These hydrophobic surfaces are expected to have potential applications for self-cleaning.

  9. Acetone gas-sensing properties of multiple-networked Pd-decorated Bi_2O_3 nanorod sensors

    Park, Sung Hoon; Kim, Soo Hyun; Lee, Sang Min; Lee, Chong Mu

    2015-01-01

    This study examined the sensing properties of Bi_2O_3 nanorods decorated with Pd nanoparticles. Pd-decorated β-Bi_2O_3 nanorods were prepared by immersing the Bi_2O_3 nanorods in ethanol/(50 mM)PdCl_2 solution followed by UV irradiation and annealing. The Bi_2O_3 nanorods decorated with Pd nanoparticles showed faster and stronger response to acetone gas than the pristine Bi_2O_3 nanorods. Interestingly, the difference in response time between the Pd-decorated Bi_2O_3 nanorod sensor and pristine Bi_2O_3 nanorod sensor increased with increasing the acetone gas concentration. In contrast, the difference in recovery time between the two nanorod sensors decreased with increasing the acetone gas concentration. This difference can be explained using the chemical mechanism. The underlying mechanism for the enhanced response of the Bi_2O_3 nanorods decorated with Pd nanoparticles to acetone gas is also discussed

  10. Electrical anisotropy properties of ZnO nanorods analyzed by conductive atomic force microscopy

    Wu Yunfeng; Yu Naisen; Liu Dongping; He Yangyang; Liu Yuanda; Liang Hongwei; Du Guotong

    2013-01-01

    Highlights: ► The electrical properties of one individual lying ZnO nanorod were performed by C-AFM measurement. ► Inhomogeneous spatial current distribution was detected. ► Current was detected along the side facets while no current was detected in the top plane for ZnO nanorod. ► The side facets were more conductive than the top facets of ZnO nanorods. - Abstract: In this study, we have prepared ZnO nanorods on cracked GaN substrates using aqueous solution method. Unique electrical characterization of one individual lying ZnO nanorod is analyzed by conductive atomic force microscopy (C-AFM). Effect of anisotropy properties on the conductivity of a single nanorod has been investigated. The current maps of ZnO nanorods have been simultaneously recorded with the topography which is gained by AFM-contact mode. The C-AFM measurement present local current–voltage (I–V) characteristics of the side facets of one individual lying nanorod, however, no current is detected on the top facets of ZnO nanorods. Measurement results indicate that the side facets are more electrically active than the top facets of ZnO nanorods due to lower Schottky barrier height of the side facets.

  11. Synthesis of non-aggregated nicotinic acid coated magnetite nanorods via hydrothermal technique

    Attallah, Olivia A., E-mail: olivia.adly@hu.edu.eg [Center of Nanotechnology, Nile University, 12677 Giza (Egypt); Pharmaceutical Chemistry Department, Heliopolis University, 11777 El Salam, Cairo (Egypt); Girgis, E. [Solid State Physics Department, National Research Center, 12622 Dokki, Giza (Egypt); Advanced Materials and Nanotechnology Lab, CEAS, National Research Center, 12622 Dokki, Giza (Egypt); Abdel-Mottaleb, Mohamed M.S.A. [Center of Nanotechnology, Nile University, 12677 Giza (Egypt)

    2016-02-01

    Non-aggregated magnetite nanorods with average diameters of 20–30 nm and lengths of up to 350 nm were synthesized via in situ, template free hydrothermal technique. These nanorods capped with different concentrations (1, 1.5, 2 and 2.5 g) of nicotinic acid (vitamin B3); possessed good magnetic properties and easy dispersion in aqueous solutions. Our new synthesis technique maintained the uniform shape of the nanorods even with increasing the coating material concentration. The effect of nicotinic acid on the shape, particle size, chemical structure and magnetic properties of the prepared nanorods was evaluated using different characterization methods. The length of nanorods increased from 270 nm to 350 nm in nicotinic acid coated nanorods. Goethite and magnetite phases with different ratios were the dominant phases in the coated samples while a pure magnetite phase was observed in the uncoated one. Nicotinic acid coated magnetic nanorods showed a significant decrease in saturation magnetization than uncoated samples (55 emu/g) reaching 4 emu/g in 2.5 g nicotinic acid coated sample. The novel synthesis technique proved its potentiality to prepare coated metal oxides with one dimensional nanostructure which can function effectively in different biological applications. - Highlights: • We synthesize nicotinic acid coated magnetite nanorods via hydrothermal technique • Effect of nicotinic acid concentration on the nanorods properties was significant • Nanorods maintained uniform shape with increased concentration of nicotinic acid • Alterations occurred in particle size, mineral phases and magnetics of coated samples.

  12. Pre-fabricated nanorods in RE–Ba–Cu–O superconductors

    Khatri, N D; Majkic, G; Shi, T; Selvamanickam, V; Chen, Y

    2013-01-01

    Pre-fabrication of metallic nanorods on biaxially textured templates has been explored in this study to introduce flux pinning centers in RE–Ba–Cu–O (REBCO, RE =rare earth) based superconductors. Pt nanorods were deposited by an electron beam assisted deposition method on LaMnO 3 -capped biaxially textured IBAD-(ion beam assisted deposition) substrates. Well-controlled nanorods with varying diameter (50–120 nm), length (up to 1 μm), orientation and unit cell size were grown over an area of 120–150 μm 2 . The nanorod-decorated samples were then deposited with Gd–Y–Ba–Cu–O ((Gd, Y)BCO) by metal organic chemical vapor deposition (MOCVD). The Pt nanorods remain in their positions during MOCVD and become embedded in the (Gd, Y)BCO matrix, although they suffer creep-induced shape deformation due to exposure to elevated temperature. Higher unit cell size, longer nanorods, and nanorods oriented at an angle to the substrate normal adversely affect the epitaxy of the (Gd, Y)BCO film due to formation of a-axis grains. The observed current-carrying capacity of the Pt nanorod sample is lower than its corresponding reference sample without any nanorods and processed under identical conditions, but it decreases at a slower rate with increasing magnetic field. Potential routes to improve the performance while retaining the desirable characteristics of controlled nanorod direction and density are discussed. (paper)

  13. Synthesis and characterizations of Pt nanorods on electrospun polyamide-6 nanofibers templates

    Nirmala, R.; Navamathavan, R.; Won, Jeong Jin; Jeon, Kyung Soo; Yousef, Ayman; Kim, Hak Yong

    2012-01-01

    Highlights: ► Electrospun polyamide-6 nanofibers were used as the templates for synthesis Pt nanorods. ► Polyamide-6 nanofibers surfaces were plasma treated to coat Pt. ► High quality Pt nanorods were obtained by calcinations process. ► Pt nanorods with a diameter of few hundred nanometers were obtained. ► Polyamide-6 nanofibers template based Pt nanorods synthesis are a feasible method. - Abstract: We report on the synthesis of platinum (Pt) nanorods by using ultrafine polyamide-6 nanofibers templates produced via electrospinning technique. These ultrafine polyamide-6 nanofibers can be utilized as the templates for growing Pt nanorods after modifying them optimally by plasma passivations. The morphological, structural, optical and electrical properties of the template assisted Pt nanorods were studied by field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), photoluminescence (PL) and current–voltage (I–V) characteristics. The ability to fabricate the ultrafine size controlled Pt nanorods on polyamide-6 templates with optimized growth parameters in real time can be utilized for the variety of technological applications. Therefore, it is possible to obtain high quality with size control Pt nanorods. Once obtaining the high quality metal nanorods on polymer templates, the same can be adapted for the electronic device fabrication.

  14. Synthesis of non-aggregated nicotinic acid coated magnetite nanorods via hydrothermal technique

    Attallah, Olivia A.; Girgis, E.; Abdel-Mottaleb, Mohamed M.S.A.

    2016-01-01

    Non-aggregated magnetite nanorods with average diameters of 20–30 nm and lengths of up to 350 nm were synthesized via in situ, template free hydrothermal technique. These nanorods capped with different concentrations (1, 1.5, 2 and 2.5 g) of nicotinic acid (vitamin B3); possessed good magnetic properties and easy dispersion in aqueous solutions. Our new synthesis technique maintained the uniform shape of the nanorods even with increasing the coating material concentration. The effect of nicotinic acid on the shape, particle size, chemical structure and magnetic properties of the prepared nanorods was evaluated using different characterization methods. The length of nanorods increased from 270 nm to 350 nm in nicotinic acid coated nanorods. Goethite and magnetite phases with different ratios were the dominant phases in the coated samples while a pure magnetite phase was observed in the uncoated one. Nicotinic acid coated magnetic nanorods showed a significant decrease in saturation magnetization than uncoated samples (55 emu/g) reaching 4 emu/g in 2.5 g nicotinic acid coated sample. The novel synthesis technique proved its potentiality to prepare coated metal oxides with one dimensional nanostructure which can function effectively in different biological applications. - Highlights: • We synthesize nicotinic acid coated magnetite nanorods via hydrothermal technique • Effect of nicotinic acid concentration on the nanorods properties was significant • Nanorods maintained uniform shape with increased concentration of nicotinic acid • Alterations occurred in particle size, mineral phases and magnetics of coated samples.

  15. Efficient Translation of Epstein-Barr Virus (EBV) DNA Polymerase Contributes to the Enhanced Lytic Replication Phenotype of M81 EBV.

    Church, Trenton Mel; Verma, Dinesh; Thompson, Jacob; Swaminathan, Sankar

    2018-03-15

    Epstein-Barr virus (EBV) is linked to the development of both lymphoid and epithelial malignancies worldwide. The M81 strain of EBV, isolated from a Chinese patient with nasopharyngeal carcinoma (NPC), demonstrates spontaneous lytic replication and high-titer virus production in comparison to the prototype B95-8 EBV strain. Genetic comparisons of M81 and B95-8 EBVs were previously been performed in order to determine if the hyperlytic property of M81 is associated with sequence differences in essential lytic genes. EBV SM is an RNA-binding protein expressed during early lytic replication that is essential for virus production. We compared the functions of M81 SM and B95-8 SM and demonstrate that polymorphisms in SM do not contribute to the lytic phenotype of M81 EBV. However, the expression level of the EBV DNA polymerase protein was much higher in M81- than in B95-8-infected cells. The relative deficiency in the expression of B95-8 DNA polymerase was related to the B95-8 genome deletion, which truncates the BALF5 3' untranslated region (UTR). Similarly, the insertion of bacmid DNA into the widely used recombinant B95-8 bacmid creates an inefficient BALF5 3' UTR. We further showed that the while SM is required for and facilitates the efficient expression of both M81 and B95-8 mRNAs regardless of the 3' UTR, the BALF5 3' UTR sequence is important for BALF5 protein translation. These data indicate that the enhanced lytic replication and virus production of M81 compared to those of B95-8 are partly due to the robust translation of EBV DNA polymerase required for viral DNA replication due to a more efficient BALF5 3' UTR in M81. IMPORTANCE Epstein-Barr virus (EBV) infects more than 90% of the human population, but the incidence of EBV-associated tumors varies greatly in different parts of the world. Thus, understanding the connection between genetic polymorphisms from patient isolates of EBV, gene expression phenotypes, and disease is important and may help in

  16. First insights into the functional role of vasicentric tracheids and parenchyma in eucalyptus species with solitary vessels: do they contribute to xylem efficiency or safety?

    Barotto, Antonio José; Fernandez, María Elena; Gyenge, Javier; Meyra, Ariel; Martinez-Meier, Alejandro; Monteoliva, Silvia

    2016-12-01

    The relationship between hydraulic specific conductivity (k s ) and vulnerability to cavitation (VC) with size and number of vessels has been studied in many angiosperms. However, few of the studies link other cell types (vasicentric tracheids (VT), fibre-tracheids, parenchyma) with these hydraulic functions. Eucalyptus is one of the most important genera in forestry worldwide. It exhibits a complex wood anatomy, with solitary vessels surrounded by VT and parenchyma, which could serve as a good model to investigate the functional role of the different cell types in xylem functioning. Wood anatomy (several traits of vessels, VT, fibres and parenchyma) in conjunction with maximum k s and VC was studied in adult trees of commercial species with medium-to-high wood density (Eucalyptus globulus Labill., Eucalyptus viminalis Labill. and Eucalyptus camaldulensis Dehnh.). Traits of cells accompanying vessels presented correlations with functional variables suggesting that they contribute to both increasing connectivity between adjacent vessels-and, therefore, to xylem conduction efficiency-and decreasing the probability of embolism propagation into the tissue, i.e., xylem safety. All three species presented moderate-to-high resistance to cavitation (mean P 50 values = -2.4 to -4.2 MPa) with no general trade-off between efficiency and safety at the interspecific level. The results in these species do not support some well-established hypotheses of the functional meaning of wood anatomy. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  17. WO{sub 3} nanorods prepared by low-temperature seeded growth hydrothermal reaction

    Ng, Chai Yan [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Abdul Razak, Khairunisak, E-mail: khairunisak@eng.usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); NanoBiotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lockman, Zainovia, E-mail: zainovia@eng.usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2014-03-05

    Highlights: • WO{sub 3} nanorods with 5–10 nm diameter were grown directly on seeded tungsten foil. • WO{sub 3} nanorods were successfully grown at low temperature of 80 °C. • WO{sub 3} nanorods were grown on the entire surface of the seed layer after 24 h. • Annealed nanorods showed better electrochromic properties than as-made nanorods. -- Abstract: This work describes the first tungsten oxide (WO{sub 3}) nanorods hydrothermally grown on W foil. WO{sub 3} nanorods were successfully grown at low hydrothermal temperature of 80 °C by seeded growth hydrothermal reaction. The seed layer was prepared by thermally oxidized the W foil at 400 °C for 0.5 h. This work discusses the effect of hydrothermal reaction and annealing period on the morphological, structural, and electrochromic properties of WO{sub 3} nanorods. Various hydrothermal reaction periods (8–24 h) were studied. Monoclinic WO{sub 3} nanorods with 5–10 nm diameter were obtained after hydrothermal reaction for 24 h. These 24 h WO{sub 3} nanorods were also annealed at 400 °C with varying dwelling periods (0.5–4 h). Electrochromic properties of WO{sub 3} nanorods in an acidic electrolyte were analyzed using cyclic voltammetry and UV–vis spectrophotometry. WO{sub 3} nanorods annealed at 400 °C for 1 h showed the highest charge capacity and the largest optical contrast among the 24 h WO{sub 3} films. The sample also showed good cycling stability without significant degradation. Based on the results, the reaction mechanism of WO{sub 3} nanorod formation on W foil was proposed.

  18. Luminescence properties of hydrothermally grown ZnO nanorods

    Yatskiv, Roman; Grym, Jan

    2016-01-01

    Roč. 99, 1November (2016), s. 214-220 ISSN 0749-6036 R&D Projects: GA MŠk(CZ) LD14111; GA ČR GA15-17044S Institutional support: RVO:67985882 Keywords : Photoluminescence * Annealing * ZnO nanorods Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.123, year: 2016

  19. Sodium titanate nanorods: Preparation, microstructure characterization and photocatalytic activity

    Štengl, Václav; Bakardjieva, Snejana; Šubrt, Jan; Večerníková, Eva; Szatmáry, Lórant; Klementová, Mariana; Balek, Vladimír

    2006-01-01

    Roč. 63, 1-2 (2006), s. 20-30 ISSN 0926-3373 R&D Projects: GA MŠk 1M0577 Institutional research plan: CEZ:AV0Z40320502 Keywords : sodium titanate * nanorods * ethylene glycol Subject RIV: CA - Inorganic Chemistry Impact factor: 3.942, year: 2006

  20. Co-catalyst free Titanate Nanorods for improved Hydrogen ...

    Herein, we report a simplified method for the preparation of photo-active titanate nanorods catalyst .... The TEM images were taken with Philips Technai G2 FEI F12 trans- mission electron microscope operating at 80-100 kV. Optical properties were measured in DRS ..... Chen X, Shen S, Guo L and Mao S S 2010 Chem. Rev ...

  1. Detecting Casimir torque with an optically levitated nanorod

    Xu, Zhujing; Li, Tongcang

    2017-09-01

    The linear momentum and angular momentum of virtual photons of quantum vacuum fluctuations can induce the Casimir force and the Casimir torque, respectively. While the Casimir force has been measured extensively, the Casimir torque has not been observed experimentally though it was predicted over 40 years ago. Here we propose to detect the Casimir torque with an optically levitated nanorod near a birefringent plate in vacuum. The axis of the nanorod tends to align with the polarization direction of the linearly polarized optical tweezer. When its axis is not parallel or perpendicular to the optical axis of the birefringent crystal, it will experience a Casimir torque that shifts its orientation slightly. We calculate the Casimir torque and Casimir force acting on a levitated nanorod near a birefringent crystal. We also investigate the effects of thermal noise and photon recoils on the torque and force detection. We prove that a levitated nanorod in vacuum will be capable of detecting the Casimir torque under realistic conditions, and will be an important tool in precision measurements.

  2. Ionic liquid intercalated V2O5 nanorods: synthesis and ...

    Administrator

    materials for lithium ion battery, catalyst for photocata- lytic degradation ... ties.5,6 This compound is widely studied and is a promising material, both in the pure .... Figure 3 shows the Raman spectra of IL-V2O5 nanorods and calcined V2O5 ...

  3. Graphite/ZnO nanorods junction for ultraviolet photodetectors

    Yatskiv, Roman; Grym, Jan; Verde, Maria

    2015-01-01

    Roč. 105, March 2015 (2015), s. 70-73 ISSN 0038-1101 R&D Projects: GA MŠk(CZ) LD14111 Institutional support: RVO:67985882 Keywords : ZnO nanorods * Graphite based junction * UV photodetector Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.345, year: 2015

  4. Synthesis and super-paramagnetic properties of neodymium ferrites nanorods

    El moussaoui, H. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Laboratoire of Magnetism and the Physics of the High Energies, URAC 12, Departement of Physique, Faculty of Science, Mohammed V- Agdal University, BP 1014, Rabat (Morocco); Mounkachi, O., E-mail: o.mounkachi@mascir.com [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Masrour, R. [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, Route Sidi Bouzid, BP 63, 46000 Safi (Morocco); Hamedoun, M., E-mail: hamedoun@hotmail.com [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Hlil, E.K. [Institut Néel, CNRS-UJF, B.P. 166, 38042 Grenoble Cedex (France); Benyoussef, A. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Laboratoire of Magnetism and the Physics of the High Energies, URAC 12, Departement of Physique, Faculty of Science, Mohammed V- Agdal University, BP 1014, Rabat (Morocco); Hassan II Academy of Science and Technology, Rabat (Morocco)

    2013-12-25

    Highlights: •Magnetic properties of Neodymium nanorods depend on calcination temperature. •The as-synthesized Nd ferrite nanorods are superparamagnetic at room temperature. •The blocking temperature is higher than room temperature. -- Abstract: In this work we report the microstructural characterization and the magnetic properties of neodymium ferrites (NdFe{sub 2}O{sub 4}) nanorods prepared by well controlled co-precipitation method. The effect of annealing temperature on the structure, morphology and magnetic properties of NdFe{sub 2}O{sub 4} has been investigated. The transmission electron microscopy (TEM) observations revealed that the as-prepared nanoparticles have rods-like shape with the average diameter ranging from 5 to 14 nm and uniform length. The magnetic measurements show that the as-synthesized nanorods have a superparamagnetic behavior at room temperature, with a blocking temperature of 360 K and magnetic anisotropy constant of 2.8 × 10{sup 5} ergs/cm{sup 3}. The magnetization and coercitivity at room temperature are increased from 26 to 34 emu/g and from 151 to 171 Oe with increasing annealing temperature from 400 to 600 °C, respectively.

  5. Attachment of Quantum Dots on Zinc Oxide Nanorods

    Seay, Jared; Liang, Huan; Harikumar, Parameswar

    2011-03-01

    ZnO nanorods grown by hydrothermal technique are of great interest for potential applications in photovoltaic and optoelectronic devices. In this study we investigate the optimization of the optical absorption properties by a low temperature, chemical bath deposition technique. Our group fabricated nanorods on indium tin oxide (ITO) substrate with precursor solution of zinc nitrate hexahydrate and hexamethylenetramine (1:1 molar ratio) at 95C for 9 hours. In order to optimize the light absorption characteristics of ZnO nanorods, CdSe/ZnS core-shell quantum dots (QDs) of various diameters were attached to the surface of ZnO nanostructures grown on ITO and gold-coated silicon substrates. Density of quantum dots was varied by controlling the number drops on the surface of the ZnO nanorods. For a 0.1 M concentration of QDs of 10 nm diameter, the PL intensity at 385 nm increased as the density of the quantum dots on ZnO nanostructures was increased. For quantum dots at 1 M concentration, the PL intensity at 385 nm increased at the beginning and then decreased at higher density. We will discuss the observed changes in PL intensity with QD concentration with ZnO-QD band structure and recombination-diffusion processes taking place at the interface.

  6. Electrorheological properties of suspensions of polypyrrole coated titanate nanorods

    Mrlík, M.; Pavlínek, V.; Saha, P.; Quadrat, Otakar

    2011-01-01

    Roč. 21, č. 5 (2011), 52365_1-52365_7 ISSN 1430-6395 R&D Projects: GA ČR GA202/09/1626 Institutional research plan: CEZ:AV0Z40500505 Keywords : polypyrrole * nanorods * electrorheology Subject RIV: BK - Fluid Dynamics Impact factor: 1.000, year: 2011

  7. Antimicrobial potentials of silver colloidal (nanorods) on clinical ...

    Antimicrobial resistance in developing countries has long been an issue of major concern. Nanotechnology has become an eye opener for the intervention on multiple drug resistance organisms. In this study we investigated the antimicrobial potentials of Silver Nitrate (nanorods) solution used in managing infectious ...

  8. Use of ionic liquids in synthesis of nanocrystals, nanorods and ...

    TECS

    chalcogen powder (Se and Te) and NaBH4 in imidazolium[BMIM]-based ionic liquids as solvents at 180–200°C. Nanorods and nanowires of Se and Te ... such as elemental chalcogens and metal chalcogenides. Nanoparticles of Rh and Ir have been ... Single crystalline Te nanotubes have been synthesized by the polyol ...

  9. Two step continuous method to synthesize colloidal spheroid gold nanorods.

    Chandra, S; Doran, J; McCormack, S J

    2015-12-01

    This research investigated a two-step continuous process to synthesize colloidal suspension of spheroid gold nanorods. In the first step; gold precursor was reduced to seed-like particles in the presence of polyvinylpyrrolidone and ascorbic acid. In continuous second step; silver nitrate and alkaline sodium hydroxide produced various shape and size Au nanoparticles. The shape was manipulated through weight ratio of ascorbic acid to silver nitrate by varying silver nitrate concentration. The specific weight ratio of 1.35-1.75 grew spheroid gold nanorods of aspect ratio ∼1.85 to ∼2.2. Lower weight ratio of 0.5-1.1 formed spherical nanoparticle. The alkaline medium increased the yield of gold nanorods and reduced reaction time at room temperature. The synthesized gold nanorods retained their shape and size in ethanol. The surface plasmon resonance was red shifted by ∼5 nm due to higher refractive index of ethanol than water. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Enhancement of UV photodetector properties of ZnO nanorods/PEDOT:PSS Schottky junction by NGQD sensitization along with conductivity improvement of PEDOT:PSS by DMSO additive

    Dhar, Saurab; Majumder, Tanmoy; Chakraborty, Pinak; Mondal, Suvra Prakash

    2018-04-01

    Schottky junction ultraviolet (UV) photodetector was fabricated by spin coating a hole conducting polymer, poly 3,4-ethylenedioxythiophene: polystyrene sulfonate (PEDOT:PSS) on hydrothermally grown zinc oxide (ZnO) nanorod arrays. The UV detector performance was significantly improved two step process. Firstly, ZnO nanorods were modified by sensitizing N doped grapheme quantum dots (NGQDs) for better photoresponce behavior. Afterwards, the junction properties as well as photoresponse was enhanced by modifying electrical conductivity of PEDOT:PSS layer with organic solvent (DMSO). Our NGQD decorated ZnO NRs/DMSO-PEDOT:PSS Schottky junction device demonstrated superior external quantum efficiency (EQE ˜ 90063 %) and responsivity (Rλ˜247 A/W) at 340 nm wavelength and -1V external bias. The response and recovery times of the final photodetector device was very fast compared to GQD as well as NGQD modified and pristine ZnO nanorod based detectors.

  11. Charge separation in branched TiO{sub 2} nanorod array homojunction aroused by quantum effect for enhanced photocatalytic decomposition of gaseous benzene

    Wang, Xiaoxia [State Key Laboratory of Materials and Processing Die & Mould Technology, Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Wuhan 430062 (China); Ni, Qian [State Key Laboratory of Materials and Processing Die & Mould Technology, Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Zeng, Dawen, E-mail: dwzeng@mail.hust.edu.cn [State Key Laboratory of Materials and Processing Die & Mould Technology, Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Wuhan 430062 (China); Liao, Guanglan [State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Xie, Changsheng [State Key Laboratory of Materials and Processing Die & Mould Technology, Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China)

    2016-12-15

    Highlights: • Charge separation in homojunction based on the broadened band gap by quantum effect. • Absolute charge separation by the passivation effect of TiO{sub 2} nanorod. • Long-distance electron transfer behavior in photocatalysis. • Roughed surface for enhanced light harvesting by light trapping effect. - Abstract: As known, the electron transfer behavior in photocatalysis is short-distance transportation, which leads the photo-induced electrons and holes to be localized. The temporarily separated electrons and holes will recombine with each other in the localized region. In this paper, we successfully achieved electron transfer in a homojunction of branched rutile TiO{sub 2} nanorod @nanoparticle core-shell architecture by quantum confinement effect aroused by the nanoparticle, which is proved by the blue-shifting in UV–vis absorption spectrum of the homojunction. Meanwhile, an absolute charge separation is also achieved by the long-distance electron transfer along the single-crystalline rutile TiO{sub 2} nanorod as uninterrupted high-speed electron transfer channel to FTO substrates. Based on the effective charge separation, the photocatalytic decomposition of gaseous benzene by the homojunction is significantly enhanced, yielding 10 times CO{sub 2} than that of the nanorod array. This homojunction interfacial charge separation, aroused by quantum effect, through long-distance transfer along the single-crystalline nanorod gives us inspiration to achieve efficient charge separation with defect-less interfaces, which might can be utilized for real-time environmental abatement and energy generation simultaneously.

  12. Full phosphorescent white-light organic light-emitting diodes with improved color stability and efficiency by fine tuning primary emission contributions

    Wang Hua

    2014-02-01

    Full Text Available In this paper, a novel type of white-light organic light emitting diode (OLED with high color stability was reported, in which the yellow-light emission layer of (4,4′-N,N′-dicarbazolebiphenyl (CBP : tris(2-phenylquinoline-C2,N′iridium(III (Ir(2-phq3 was sandwiched by double blue-light emission layers of 1,1-bis-[(di-4-tolylaminopheny1]cyclohexane (TAPC : bis[4,6-(di-fluorophenyl-pyridinato-N,C2′]picolinate (FIrpic and tris[3-(3-pyridylmesityl]borane (3TPYMB:FIrpic. And, it exhibited the maximum current efficiency of 33.1 cd/A, the turn-on voltage at about 3 V and the maximum luminance in excess of 20000 cd/m2. More important, it realized very stable white-light emission, and its CIE(x, y coordinates only shift from (0.34, 0.37 to (0.33, 0.37 as applied voltage increased from 5 V to 12 V. It is believed that the new scheme in emission layer of white-light OLED can fine tune the contribution of primary emission with applied voltage changed, resulting in high quality white-light OLED.

  13. Full phosphorescent white-light organic light-emitting diodes with improved color stability and efficiency by fine tuning primary emission contributions

    Hua, Wang, E-mail: wmsu2008@sinano.ac.cn, E-mail: wanghua001@tyut.edu.cn; Du, Xiaogang [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan 030024 (China); Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Su, Wenming, E-mail: wmsu2008@sinano.ac.cn, E-mail: wanghua001@tyut.edu.cn; Zhang, Dongyu [Printable Electronics Research Centre, Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, suzhou 215123 (China); Lin, Wenjing [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan 030024 (China); Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Printable Electronics Research Centre, Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, suzhou 215123 (China)

    2014-02-15

    In this paper, a novel type of white-light organic light emitting diode (OLED) with high color stability was reported, in which the yellow-light emission layer of (4,4{sup ′}-N,N{sup ′}-dicarbazole)biphenyl (CBP) : tris(2-phenylquinoline-C2,N{sup ′})iridium(III) (Ir(2-phq){sub 3}) was sandwiched by double blue-light emission layers of 1,1-bis-[(di-4-tolylamino)pheny1]cyclohexane (TAPC) : bis[4,6-(di-fluorophenyl)-pyridinato-N,C2{sup ′}]picolinate (FIrpic) and tris[3-(3-pyridyl)mesityl]borane (3TPYMB):FIrpic. And, it exhibited the maximum current efficiency of 33.1 cd/A, the turn-on voltage at about 3 V and the maximum luminance in excess of 20000 cd/m{sup 2}. More important, it realized very stable white-light emission, and its CIE(x, y) coordinates only shift from (0.34, 0.37) to (0.33, 0.37) as applied voltage increased from 5 V to 12 V. It is believed that the new scheme in emission layer of white-light OLED can fine tune the contribution of primary emission with applied voltage changed, resulting in high quality white-light OLED.

  14. Full phosphorescent white-light organic light-emitting diodes with improved color stability and efficiency by fine tuning primary emission contributions

    Hua, Wang; Du, Xiaogang; Su, Wenming; Lin, Wenjing; Zhang, Dongyu

    2014-02-01

    In this paper, a novel type of white-light organic light emitting diode (OLED) with high color stability was reported, in which the yellow-light emission layer of (4,4'-N,N'-dicarbazole)biphenyl (CBP) : tris(2-phenylquinoline-C2,N')iridium(III) (Ir(2-phq)3) was sandwiched by double blue-light emission layers of 1,1-bis-[(di-4-tolylamino)pheny1]cyclohexane (TAPC) : bis[4,6-(di-fluorophenyl)-pyridinato-N,C2']picolinate (FIrpic) and tris[3-(3-pyridyl)mesityl]borane (3TPYMB):FIrpic. And, it exhibited the maximum current efficiency of 33.1 cd/A, the turn-on voltage at about 3 V and the maximum luminance in excess of 20000 cd/m2. More important, it realized very stable white-light emission, and its CIE(x, y) coordinates only shift from (0.34, 0.37) to (0.33, 0.37) as applied voltage increased from 5 V to 12 V. It is believed that the new scheme in emission layer of white-light OLED can fine tune the contribution of primary emission with applied voltage changed, resulting in high quality white-light OLED.

  15. Visible-light wavelength matched microsphere assembly of TiO{sub 2} superfine nanorods and the enhanced photovoltaic performance

    Tao, Xiyun; Wang, Yumin; Zhang, Xiang; Sun, Hongxia; Zhang, Qingsong; Niu, Laiyou; Liu, Juan; Zhou, Xingfu, E-mail: Zhouxf@njtech.edu.cn

    2015-05-15

    Graphical abstract: A novel visible-light wavelength matched microspheres assembly of TiO{sub 2} superfine nanorods with a diameter of ∼5 nm was fabricated via a hydrothermal method. The as-prepared rutile TiO{sub 2} microspheres have a uniform diameter of ∼450 nm and show a good light-trapping performance. Dye-sensitized solar cell based on this sample shows a satisfactory energy conversion efficiency of 6.59% and is the highest PCE reported for intrinsic rutile TiO{sub 2}. The further optimized DSSC shows a conversion efficiency of 8.3%, though the internal resistance is higher and the dye absorption is lower than that of widely used anatase TiO{sub 2} nanoparticles. - Highlights: • Microsphere assembly of TiO{sub 2} nanorods with a diameter of ∼5 nm was fabricated. • TiO{sub 2} microspheres size is well matched with the visible light wavelength. • TiO{sub 2} microsphere enhances the light-scattering ability. • Rutile TiO{sub 2} microsphere shows an energy conversion efficiency of 6.59%. • The highest PCE reported for intrinsic rutile TiO{sub 2} is obtained. - Abstract: According to the Mie scattering theory, spheres with the size matched with light wavelength are most suitable for light scattering and enhance the light trapping ability. In this paper, a novel visible-light wavelength matched sphere assembly of TiO{sub 2} superfine nanorods was fabricated via a simple one-step hydrothermal method. The morphology and the structure were examined by field emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). The visible subwavelength TiO{sub 2} microsphere resembling an immature chinese chestnut is composed of countless superfine TiO{sub 2} nanorods, the diameter of these building blocks of superfine TiO{sub 2} nanorods is ∼5 nm. The obtained TiO{sub 2} sphere has an average diameter of ca. 450 nm, which matches well with the visible light wavelength and cause the

  16. Nanorod diameter modulated osteogenic activity of hierarchical micropore/nanorod-patterned coatings via a Wnt/β-catenin pathway.

    Zhou, Jianhong; Zhao, Lingzhou; Li, Bo; Han, Yong

    2018-04-14

    Hierarchical micropore/nanorod-patterned strontium doped hydroxyapatite (Ca 9 Sr 1 (PO 4 ) 6 (OH) 2 , Sr 1 -HA) structures (MNRs) with different nanorod diameters of about 30, 70 and 150 nm were coated on titanium, to investigate the effect of nanorod diameter on osteogenesis and the involved mechanism. Compared to micropore/nanogranule-patterned Sr 1 -HA coating (MNG), MNRs gave rise to dramatically enhanced in vitro mesenchymal stem cell functions including osteogenic differentiation in the absence of osteogenic supplements and in vivo osseointegration related to the nanorod diameter with about 70 nm displaying the best effects. MNRs activated the cellular Wnt/β-catenin pathway by increasing the expression of Wnt3a and LRP6 and decreasing the expression of Wnt/β-catenin pathway antagonists (sFRP1, sFRP2, Dkk1 and Dkk2). The exogenous Wnt3a significantly enhanced the β-catenin signaling activation and cell differentiation on MNG, and the exogenous Dkk1 attenuated the enhancing effect of MNRs on them. The data demonstrate that MNRs favor osseointegration via a Wnt/β-catenin pathway. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Imidazolium ionic liquid induced one-step synthesis of -Fe2O3 nanorods and nanorod assemblies for lithium-ion battery

    Shuting Xie

    2016-12-01

    Full Text Available α-Fe2O3 nanorods and nanorod assemblies are prepared via a facile one-step method with the assistance of imidazolium-based ionic liquid. The aspect ratio of synthesized nanorods is determined by the alkyl chain length of [Cnmim]+. The inter-molecular π−π interaction and intra-molecular dipole-dipole interaction among imidazole rings of [C4mim]+[PhCOO]− play critical roles in both nucleation and assembly processes of α-Fe2O3 nanorods. The α-Fe2O3 nanorod assemblies show an excellent performance in lithium-ion batteries with a reversible capacity of 1007.3 mA h g−1 at the rate of 500 mA g−1 after 150 cycles.

  18. Surface passivation function of indium-tin-oxide-based nanorod structural sensors

    Lin, Tzu-Shun; Lee, Ching-Ting; Lee, Hisn-Ying; Lin, Chih-Chien

    2012-01-01

    Employing self-shadowing traits of an oblique-angle electron-beam deposition system, various indium tin oxide (ITO) nanorod arrays were deposited on a silicon substrate and used as extended-gate field-effect-transistor (EGFET) pH sensors. The length and morphology of the deposited ITO nanorod arrays could be changed and controlled under different deposition conditions. The ITO nanorod structural EGFET pH sensors exhibited high sensing performances owing to the larger sensing surface area. The sensitivity of the pH sensors with 150-nm-length ITO nanorod arrays was 53.96 mV/pH. By using the photoelectrochemical treatment of the ITO nanorod arrays, the sensitivity of the pH sensors with 150-nm-length passivated ITO nanorod arrays was improved to 57.21 mV/pH.

  19. Simple and polarization-independent Dammann grating based on all-dielectric nanorod array

    Yang, Sen; Li, Chuang; Liu, Tongming; Da, Haixia; Feng, Rui; Tang, Donghua; Sun, Fangkui; Ding, Weiqiang

    2017-09-01

    In this work, we comprehensively investigate a Dammann grating (DG) that can generate a 5 × 5 diffraction spot array with an extending angle of 18^\\circ × 18^\\circ around the fiber communication wavelength of 1550 {nm}. The DG is a simple metasurface structure composed of a silicon cuboid nanorod array on a silica substrate, and only two different sizes of nanorods with square cross-sections and uniform spatial orientations are used. These simple units and this configuration are favorable in practice, and the C4 symmetry cross section of the nanorods ensures the polarization-independent operation of the DG. The phase modulation of the nanorods is achieved by the guiding mode propagating in them rather than electric or magnetic Mie-type resonance, which makes the design of the cuboid nanorods easy and robust. More importantly, the two-dimensional nanorod array is generated from a one-dimensional array, which further decreases the design and fabrication complexity.

  20. Photoswitching in azobenzene self-assembled monolayers capped on zinc oxide: nanodots vs nanorods.

    Shah, Syed Mujtaba; Martini, Cyril; Ackermann, Jörg; Fages, Frédéric

    2012-02-01

    We report the synthesis and spectroscopic characterization of nanohybrid structures consisting of an azobenzene compound grafted on the surface of zinc oxide nanoparticles. Characteristic bathochromic shifts indicate that the azobenzene photochromic molecules self-assemble onto the surface of the nanocrystals. The extent of packing is dependent on the shape of the nanoparticle. ZnO nanorods, with flat facets, enable a tighter organization of the molecules in the self-assembled monolayer than in the case of nanodots that display a more curvated shape. Consistently, the efficiency of photochromic switching of the self-assembled monolayer on ZnO nanoparticles is also shown to be strongly affected by nanoparticle shape. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Optotransfection of mammalian cells based on a femtosecond laser and facilitated by gold nanorods

    Ma, Zili; Chan, Kam T; Wang, Jianfang; Kong, Siu K; He, Sailing

    2013-01-01

    The optotransfection of cells based on a femtosecond laser has attracted much attention owing to its high transfection efficiency and high cell viability since its first report by Konig. However, the low throughput in the original method also limits its use in practical applications. Gold nanoparticles (GNPs) have been reported to function as local receivers of light to relax the requirement of accurate optical alignment for the optotransfection of single cells. However, the visible light used in such work is not suitable for penetrating deep tissues in certain applications. In this study, we employed gold nanorods (GNRs) and an infrared femtosecond laser at the wavelength of 980 nm to realize optotransfection of cells with GFP. It was found that the surface coating of GNRs exhibited a significant effect on the process of cell permeabilization. (paper)

  2. Biomcompatible gold nanorods conjugated with photosensitizers assisted for photostability and photodestructive ability

    Kuo, Wen-Shuo; Chen, Shean-Jen

    2012-02-01

    Light-exposure-mediated higher temperatures that markedly accelerate the degradation of indocyanine green (ICG) in aqueous solutions by thermal decomposition have been a serious medical problem. In this work, we present the example of using gold nanorods (Au NRs) simultaneously serving as photodynamic and photothermal agents to destroy malignant cells. Au NRs were successfully conjugated with hydrophilic photosensitizer, indocyanine green (ICG), to achieve photodynamic therapy (PDT) and photothermal therapy (PTT). We also demonstrated that Au NRs conjugated with ICG displayed high chemical stability and acted as a promising diagnostic probe. Due to its stability even via higher temperatures mediated by laser irradiation, the combination of PDT and PTT proved to be efficiently killing cancer cells as compared to PDT or PTT treatment alone and enhanced the effectiveness of photodestruction and was demonstrated to enhance its photostability.

  3. Modulating emission polarization of semiconductor quantum dots through surface plasmon of metal nanorod

    Cheng, Mu-Tian; Liu, Shao-Ding; Wang, Qu-Quan

    2008-04-01

    We theoretically investigated the dynamics of exciton populations [ρyy(t ) and ρxx(t )] on two orthogonal polarization eigenstates (∣x⟩ and ∣y⟩) and the polarization ratio P(t )=[ρyy(t )-ρxx(t )]/[ρyy(t )+ρxx(t )] of an anisotropic InGaAs quantum dot modulated by the surface plasmon of an Au nanorod (NR). In the resonance of longitudinal surface plasmon of AuNR, the polarization ratio P(t ) increases from 0.22 to 0.99 during the excitation due to the efficient enhancement of Rabi frequency of the transition between the ∣y⟩ and vacuum states, and decreases from 0.02 to -0.92 after the excitation pulse due to the enhancement of decay rate of the ∣y⟩ state. This offers an approach to modulate the dynamic polarization ratio of radiative emissions.

  4. Enhanced polarization of (11–22) semi-polar InGaN nanorod array structure

    Athanasiou, M.; Smith, R. M.; Hou, Y.; Zhang, Y.; Gong, Y.; Wang, T., E-mail: t.wang@sheffield.ac.uk [Department of Electronic and Electrical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2015-10-05

    By means of a cost effective nanosphere lithography technique, an InGaN/GaN multiple quantum well structure grown on (11–22) semipolar GaN has been fabricated into two dimensional nanorod arrays which form a photonic crystal (PhC) structure. Such a PhC structure demonstrates not only significantly increased emission intensity, but also an enhanced polarization ratio of the emission. This is due to an effective inhibition of the emission in slab modes and then redistribution to the vertical direction, thus minimizing the light scattering processes that lead to randomizing of the optical polarization. The PhC structure is designed based on a standard finite-difference-time-domain simulation, and then optically confirmed by detailed time-resolved photoluminescence measurements. The results presented pave the way for the fabrication of semipolar InGaN/GaN based emitters with both high efficiency and highly polarized emission.

  5. Enhanced polarization of (11–22) semi-polar InGaN nanorod array structure

    Athanasiou, M.; Smith, R. M.; Hou, Y.; Zhang, Y.; Gong, Y.; Wang, T.

    2015-01-01

    By means of a cost effective nanosphere lithography technique, an InGaN/GaN multiple quantum well structure grown on (11–22) semipolar GaN has been fabricated into two dimensional nanorod arrays which form a photonic crystal (PhC) structure. Such a PhC structure demonstrates not only significantly increased emission intensity, but also an enhanced polarization ratio of the emission. This is due to an effective inhibition of the emission in slab modes and then redistribution to the vertical direction, thus minimizing the light scattering processes that lead to randomizing of the optical polarization. The PhC structure is designed based on a standard finite-difference-time-domain simulation, and then optically confirmed by detailed time-resolved photoluminescence measurements. The results presented pave the way for the fabrication of semipolar InGaN/GaN based emitters with both high efficiency and highly polarized emission

  6. In vitro and in vivo photothermal cancer therapy using excited gold nanorod surface plasmons

    Chen, Cheng-Lung; Liu, Bruce; Ou, Min-Nan; Chang, Fu-Hsiung; Lin, Win-Li; Chia, Chih-Ta; Chen, Yang-Yuan

    2013-03-01

    The application of heat to eliminate or restrain specific cancer cells is proposed as an encouraging approach in optimizing cancer therapy. This talk presents the in vitro and in vivo photothermal cancer therapy using photo-excited gold nanorods (Au NRs), and studies the impact of thermal heat on the necrosis of tumor tissue. The therapeutic efficacy in vivo was evaluated by analyzing tumor size change, vascular development, and histological images. The safety standard for the therapy process and administration of Au NRs were conducted to exclude side effects arising from the irradiation and materials. It is found that the smaller size of Au NRs exhibits better therapeutic efficacy due to their optical absorption efficiency and space distribution uniformity in the cell. The generation of local heating from excited Au NR surface plasmons is high enough to make the tumor tissue gradually develop to an eschar; resulting in a dramatic size decreases in these treated tumors.

  7. N-face GaN nanorods: Continuous-flux MOVPE growth and morphological properties

    Bergbauer, W.; Strassburg, M.; Kölper, Ch.; Linder, N.; Roder, C.; Lähnemann, J.; Trampert, A.; Fündling, S.; Li, S. F.; Wehmann, H.-H.; Waag, A.

    2011-01-01

    We demonstrate the morphological properties of height, diameter and shape controlled N-face GaN nanorods (NRs) by adjusting conventional growth parameters of a standard metalorganic vapour phase epitaxy (MOVPE) growth process. Particularly the hydrogen fraction within the carrier gas was shown to be an important shaping tool for the grown nanostructures. Additionally, the aspect ratio of the NRs was successfully tuned by increasing the pitch of the nanoimprint lithography (NIL) pattern, while maintaining the hole-diameter constant. An optimum aspect ratio could be found at pitches between 400 and 800 nm, whereas larger pitches are counter-productive. The major conclusion drawn from our experiments is that the whole amount of growth material available over the masked surface contributes to the growth of the NRs.

  8. Synthesis, characterization and charge transport mechanism of CdZnO nanorods

    Mahmoud, Waleed E.; Al-Ghamdi, A.A.; El-Tantawy, F.; Al-Heniti, S.

    2009-01-01

    ZnO and Cd-doped ZnO nanostructures were prepared by new facile method at 80 deg. C. XRD measurement indicated that both samples had typical hexagonal wurtzite structures. Transmission electron microscopy (TEM) measurement shows that rod-like crystals have been formed. EDX measurement confirms the incorporation of the cadmium ion into the crystalline lattice of ZnO and indicated that cadmium ions uniformly distributed on the surface of the rods. The doping with cadmium ions has a great influence on the optical properties of the ZnO. The electrical measurements of Cd-doped ZnO nanorod were measured. The current-voltage (I-V) characteristic curve revealed that the charge transport above 4 V is mainly non-linear due to grain boundary contribution. The complex impedance spectroscopy was confirmed that the grain boundary effect controls the charge transport mechanism through CdZnO ceramic material.

  9. Field enhancement of multiphoton induced luminescence processes in ZnO nanorods

    Hyyti, Janne; Perestjuk, Marko; Mahler, Felix; Grunwald, Rüdiger; Güell, Frank; Gray, Ciarán; McGlynn, Enda; Steinmeyer, Günter

    2018-03-01

    The near-ultraviolet photoluminescence of ZnO nanorods induced by multiphoton absorption of unamplified Ti:sapphire pulses is investigated. Power dependence measurements have been conducted with an adaptation of the ultrashort pulse characterization method of interferometric frequency-resolved optical gating. These measurements enable the separation of second harmonic and photoluminescence bands due to their distinct coherence properties. A detailed analysis yields fractional power dependence exponents in the range of 3-4, indicating the presence of multiple nonlinear processes. The range in measured exponents is attributed to differences in local field enhancement, which is supported by independent photoluminescence and structural measurements. Simulations based on Keldysh theory suggest contributions by three- and four-photon absorption as well as avalanche ionization in agreement with experimental findings.

  10. An approach to fabricating chemical sensors based on ZnO nanorod arrays

    Park, Jae Young; Song, Dong Eon; Kim, Sang Sub

    2008-01-01

    Vertically and laterally aligned ZnO nanorod arrays were synthesized on Pt-coated Si substrates by catalyst-free metal organic chemical vapor deposition. An approach to fabricating chemical sensors based on the nanorod arrays using a coating-and-etching process with a photo-resist is reported. Tests of the devices as oxygen gas sensors have been performed. Our results demonstrate that the approach holds promise for the realization of sensitive and reliable nanorod array chemical sensors

  11. Synthesis and Properties of Layered-Structured Mn5O8 Nanorods

    Gao, Tao; Norby, Poul; Krumeich, Frank

    2010-01-01

    Mn5O8 nanorods were prepared by a topotactic conversion of γ-MnOOH nanorod precursors in nitrogen at 400 °C. The as-prepared Mn5O8 nanorods crystallized in a monoclinic structure (space group C2/m) with unit cell dimensions a = 10.3784(2) Å, b = 5.7337(7) Å, c = 4.8668(6) Å, and β = 109.491(6)°, ...

  12. UV and humidity sensing properties of ZnO nanorods prepared by the arc discharge method

    Fang, F; Futter, J; Markwitz, A; Kennedy, J

    2009-01-01

    The UV and humidity sensing properties of ZnO nanorods prepared by arc discharge have been studied. Scanning electron microscopy and photoluminescence spectroscopy were carried out to analyze the morphology and optical properties of the as-synthesized ZnO nanorods. Proton induced x-ray emission was used to probe the impurities in the ZnO nanorods. A large quantity of high purity ZnO nanorod structures were obtained with lengths of 0.5-1 μm. The diameters of the as-synthesized ZnO nanorods were found to be between 40 and 400 nm. The nanorods interlace with each other, forming 3D networks which make them suitable for sensing application. The addition of a polymeric film-forming agent (BASF LUVISKOL VA 64) improved the conductivity, as it facilitates the construction of conducting networks. Ultrasonication helped to separate the ZnO nanorods and disperse them evenly through the polymeric agent. Improved photoconductivity was measured for a ZnO nanorod sensor annealed in air at 200 deg. C for 30 min. The ZnO nanorod sensors showed a UV-sensitive photoconduction, where the photocurrent increased by nearly four orders of magnitude from 2.7 x 10 -10 to 1.0 x 10 -6 A at 18 V under 340 nm UV illumination. High humidity sensitivity and good stability were also measured. The resistance of the ZnO nanorod sensor decreased almost linearly with increasing relative humidity (RH). The resistance of the ZnO nanorods changed by approximately five orders of magnitude from 4.35 x 10 11 Ω in dry air (7% RH) to about 4.95 x 10 6 Ω in 95% RH air. It is experimentally demonstrated that ZnO nanorods obtained by the arc discharge method show excellent performance and promise for applications in both UV and humidity sensors.

  13. Contribution of the C-terminal tri-lysine regions of human immunodeficiency virus type 1 integrase for efficient reverse transcription and viral DNA nuclear import

    Fowke Keith R

    2005-10-01

    -terminal mutant infection, even though they displayed various low levels of nucleus-associated viral DNA, suggesting that these C-terminal mutants also impaired viral DNA integration ability. Conclusion All of these results indicate that, in addition to being involved in HIV-1 reverse transcription and integration, the C-terminal tri-lysine regions of IN also contribute to efficient viral DNA nuclear import during the early stage of HIV-1 replication.

  14. Manipulation of surface morphology of flower-like Ag/ZnO nanorods to enhance photocatalytic performance

    U-thaipan, Kasira; Tedsree, Karaked

    2018-06-01

    The surface morphology of flower-like Ag/ZnO nanorod can be manipulated by adopting different synthetic routes and also loading different levels of Ag in order to alter their surface structures to achieve the maximum photocatalytic efficiency. In a single-step preparation method Ag/ZnO was prepared by heating directly a mixture of Zn2+ and Ag+ precursors in an aqueous NaOH-ethylene glycol solution, while in the two-step preparation method an intermediate of flower-shaped ZnO nanorod was obtained by a hydrothermal process before depositing Ag particles on the ZnO surfaces by chemical reduction. The structure, morphology and optical properties of the synthesized samples were characterized using TEM, SEM, XRD, DRS and PL techniques. The sample prepared by single-step method are characterized with agglomeration of Ag atoms as clusters on the surface of ZnO, whereas in the sample prepared by two-step method Ag atoms are found uniformly dispersed and deposited as discrete Ag nanoparticles on the surface of ZnO. A significant enhancement in the adsorption of visible light was evident for Ag/ZnO samples prepared by two-step method especially with low Ag content (0.5 mol%). The flower-like Ag/ZnO nanorod prepared with 0.5 mol% Ag by two-step process was found to be the most efficient photocatalyst for the degradation of phenol, which can decompose 90% of phenol within 120 min.

  15. Silver decorated LaMnO_3 nanorod/graphene composite electrocatalysts as reversible metal-air battery electrodes

    Hu, Jie; Liu, Qiunan; Shi, Lina; Shi, Ziwei; Huang, Hao

    2017-01-01

    Graphical abstract: Silver decorated LaMnO_3 nanorod/reduced graphene oxide composite possess excellent bifunctional electrocatalytic activity and good electrochemical stability in alkaline medium. - Highlights: • Silver decorated LaMnO_3 nanorod/graphene composite were synthesized for the first time. • The ORR and OER of composite in alkaline medium were evaluated. • This composite as an efficient bifunctional catalyst has a good cycle performance. - Abstract: Perovskite LaMnO_3 nanorod/reduced graphene oxides (LMO-NR/RGO) decorated with Ag nanoparticles are studied as a bifunctional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline electrolyte. LMO-NR/RGO composites are synthesized by using cetyltrimethyl ammonium bromide (CTAB) as template via a simple hydrothermal reaction followed by heat treatment; overlaying of Ag nanoparticles is obtained through a traditional silver mirror reaction. Electron microscopy reveals that LMO-NR is embedded between the sheets of RGO, and the material is homogeneously overlaid with Ag nanoparticles. The unique composite morphology of Ag/LMO-NR/RGO not only enhances the electron transport property by increasing conductivity but also facilitates the diffusion of electrolytes and oxygen. As confirmed by electrochemical testing, Ag/LMO-NR/RGO exhibits very strong synergy with Ag nanoparticles, LMO-NR, and RGO, and the catalytic activities of Ag/LMO-NR/RGO during ORR and OER are significantly improved. With the novel catalyst, the homemade zinc-air battery can be reversibly charged and discharged and display a stable cycle performance, indicating the great potential of this composite as an efficient bifunctional electrocatalyst for metal-air batteries.

  16. Silver decorated LaMnO{sub 3} nanorod/graphene composite electrocatalysts as reversible metal-air battery electrodes

    Hu, Jie [State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao, 066004 (China); Hebei Key Laboratory of Applied Chemistry, Department of Environment and Chemistry, Yanshan University, Qinhuangdao, 066004 (China); Liu, Qiunan; Shi, Lina; Shi, Ziwei [Hebei Key Laboratory of Applied Chemistry, Department of Environment and Chemistry, Yanshan University, Qinhuangdao, 066004 (China); Huang, Hao, E-mail: huanghao@ysu.edu.cn [State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao, 066004 (China); Henan Huanghe Whirlwind Co. Ltd., Changge, 461500 (China)

    2017-04-30

    Graphical abstract: Silver decorated LaMnO{sub 3} nanorod/reduced graphene oxide composite possess excellent bifunctional electrocatalytic activity and good electrochemical stability in alkaline medium. - Highlights: • Silver decorated LaMnO{sub 3} nanorod/graphene composite were synthesized for the first time. • The ORR and OER of composite in alkaline medium were evaluated. • This composite as an efficient bifunctional catalyst has a good cycle performance. - Abstract: Perovskite LaMnO{sub 3} nanorod/reduced graphene oxides (LMO-NR/RGO) decorated with Ag nanoparticles are studied as a bifunctional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline electrolyte. LMO-NR/RGO composites are synthesized by using cetyltrimethyl ammonium bromide (CTAB) as template via a simple hydrothermal reaction followed by heat treatment; overlaying of Ag nanoparticles is obtained through a traditional silver mirror reaction. Electron microscopy reveals that LMO-NR is embedded between the sheets of RGO, and the material is homogeneously overlaid with Ag nanoparticles. The unique composite morphology of Ag/LMO-NR/RGO not only enhances the electron transport property by increasing conductivity but also facilitates the diffusion of electrolytes and oxygen. As confirmed by electrochemical testing, Ag/LMO-NR/RGO exhibits very strong synergy with Ag nanoparticles, LMO-NR, and RGO, and the catalytic activities of Ag/LMO-NR/RGO during ORR and OER are significantly improved. With the novel catalyst, the homemade zinc-air battery can be reversibly charged and discharged and display a stable cycle performance, indicating the great potential of this composite as an efficient bifunctional electrocatalyst for metal-air batteries.

  17. Thermal Reshaping of Gold Nanorods in Micellar Solution of Water/Glycerol Mixtures

    Al Sayed A. Al-Sherbini

    2010-01-01

    Full Text Available Gold nanorods (Nds with aspect ratios of 4, 3.5, and 2.8 were prepared by the electrochemical method. The nanorods were thermally studied in binary solvents of aqueous glycerol at different ratios (25%–75%. The results illustrated that the longitudinal surface plasmon resonance (SPL is strongly dependent on the dielectric constant. The maximum absorption is red shifted with increasing the glycerol/water ratio. This was attributed to the decreasing value of the dielectric constant of the binary solvents. Moreover, by increasing the temperatures, the results showed relative instability of the gold nanorods. This attributed to the relative instability of the micelle capping the nanorods.

  18. Synthesis of neodymium hydroxide nanotubes and nanorods by soft chemical process.

    Shi, Weidong; Yu, Jiangbo; Wang, Haishui; Yang, Jianhui; Zhang, Hongjie

    2006-08-01

    A facile soft chemical approach using cetyltrimethylammonium bromide (CTAB) as template is successfully designed for synthesis of neodymium hydroxide nanotubes. These nanotubes have an average outer diameter around 20 nm, inner diameter around 2 nm, and length ranging from 100 to 120 nm, high BET surface area of 495.71 m(2) g(-1). We also find that neodymium hydroxide nanorods would be obtained when CTAB absented in reaction system. The Nd(OH)3 nanorods might act as precursors that are converted into Nd2O3 nanorods through dehydration at 550 degrees C. The nanorods could exhibit upconversion emission characteristic under excitation of 591 nm at room temperature.

  19. Growth and investigation of antifungal properties of ZnO nanorod arrays on the glass

    Eskandari, M.; Haghighi, N.; Ahmadi, V.; Haghighi, F.; Mohammadi, SH.R.

    2011-01-01

    In this study, we have investigated the antifungal activity of ZnO nanorods prepared by the chemical solution method against Candida albicans. In the study, Zinc oxide nanorods have been deposited on glass substrates using the chemical solution method. The as-grown samples are characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). X-ray diffraction (XRD) showed zinc oxide nanorods grown in (0 0 2) orientation. The antifungal results indicated that ZnO nanorod arrays exhibit stable properties after two months and play an important role in the growth inhibitory of Candida albicans.

  20. Controllable growth and magnetic properties of nickel nanoclusters electrodeposited on the ZnO nanorod template

    Tang Yang; Zhao Dongxu; Shen Dezhen; Zhang Jiying; Wang Xiaohua

    2009-01-01

    The ZnO nanorods were used as a template to fabricate nickel nanoclusters by electrodeposition. The ZnO nanorod arrays act as a nano-semiconductor electrode for depositing metallic and magnetic nickel nanoclusters. The growth sites of Ni nanoclusters could be controlled by adjusting the applied potential. Under -1.15 V the Ni nanoclusters could be grown on the tips of ZnO nanorods. On increasing the potential to be more negative the ZnO nanorods were covered by Ni nanoclusters. The magnetic properties of the electrodeposited Ni nanoclusters also evolved with the applied potentials.

  1. Catalyst growth of single crystal aligned ZnO nanorods on ZnO thin films

    Zhao, Dongxu; Andreazza, Caroline; Andreazza, Pascal [Centre de Recherche sur la Matiere Divisee, CNRS-Universite d' Orleans, 1b rue de la Ferollerie, 45071 Orleans cedex 2 (France)

    2005-02-01

    One dimensional ZnO nanorods were successfully fabricated on Si substrates via a simple physical vapor-phase transport method at 950 C. A ZnO shell covered Au/Zn alloy is assumed as the nucleation site, then ZnO nanorods grow following a vapor-solid (VS) process. In order to guide the nanorod growth a c-axis oriented ZnO thin film and Au catalyst were first deposited on Si (100) surface. SEM images show nanorods grown on this substrate are vertical to the substrate surface. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Controllable growth and magnetic properties of nickel nanoclusters electrodeposited on the ZnO nanorod template

    Tang Yang; Zhao Dongxu; Shen Dezhen; Zhang Jiying [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone, Changchun 130033 (China); Wang Xiaohua, E-mail: dxzhao2000@yahoo.com.c [National Key Laboratory of High Power Semiconductor Laser, Changchun University of Science and Technology, 7089 WeiXing Road, ChangChun 130022 (China)

    2009-12-09

    The ZnO nanorods were used as a template to fabricate nickel nanoclusters by electrodeposition. The ZnO nanorod arrays act as a nano-semiconductor electrode for depositing metallic and magnetic nickel nanoclusters. The growth sites of Ni nanoclusters could be controlled by adjusting the applied potential. Under -1.15 V the Ni nanoclusters could be grown on the tips of ZnO nanorods. On increasing the potential to be more negative the ZnO nanorods were covered by Ni nanoclusters. The magnetic properties of the electrodeposited Ni nanoclusters also evolved with the applied potentials.

  3. Enhanced sensitivity of surface plasmon resonance phase-interrogation biosensor by using oblique deposited silver nanorods.

    Chung, Hung-Yi; Chen, Chih-Chia; Wu, Pin Chieh; Tseng, Ming Lun; Lin, Wen-Chi; Chen, Chih-Wei; Chiang, Hai-Pang

    2014-01-01

    Sensitivity of surface plasmon resonance phase-interrogation biosensor is demonstrated to be enhanced by oblique deposited silver nanorods. Silver nanorods are thermally deposited on silver nanothin film by oblique angle deposition (OAD). The length of the nanorods can be tuned by controlling the deposition parameters of thermal deposition. By measuring the phase difference between the p and s waves of surface plasmon resonance heterodyne interferometer with different wavelength of incident light, we have demonstrated that maximum sensitivity of glucose detection down to 7.1 × 10(-8) refractive index units could be achieved with optimal deposition parameters of silver nanorods.

  4. Exciton emission from bare and hybrid plasmonic GaN nanorods

    Mohammadi, Fatemesadat; Kunert, Gerd; Hommel, Detlef; Ge, Jingxuan; Duscher, Gerd; Schmitzer, Heidrun; Wagner, Hans Peter

    We study the exciton emission of hybrid gold nanoparticle/Alq3 (aluminiumquinoline)/wurtzite GaN nanorods. GaN nanorods of 1.5 μm length and 250 nm diameter were grown by plasma assisted MBE. Hybrid GaN nanorods were synthesized by organic molecular beam deposition. Temperature and power dependent time integrated (TI) and time resolved (TR) photoluminescence (PL) measurements were performed on bare and hybrid structures. Bare nanorods show donor (D0,X) and acceptor bound (A0,X) exciton emission at 3.473 eV and at 3.463 eV, respectively. TR-PL trace modeling reveal lifetimes of 240 ps and 1.4 ns for the (D0,X) and (A0,X) transition. 10 nm gold coated GaN nanorods show a significant PL quenching and (D0,X) lifetime shortening which is tentatively attributed to impact ionization of (D0,X) due to hot electron injection from the gold nanoparticles. This is supported by electron energy loss spectroscopy that shows a redshift of a midgap state transition indicating a reduction of a preexisting band-bending at the nanorod surface due to positive charging of the gold nanoparticles. Inserting a nominally 5 nm thick Alq3 spacer between the nanorod and the gold reduces the PL quenching and lifetime shortening. Plasmonic nanorods with a 30 nm thick Alq3 spacer reveal lifetimes which are nearly identical to uncoated GaN nanorods.

  5. FDTD simulated observation of a gold nanorod by scanning near-field optical microscopy

    Sawada, Keiji; Maruoka, Teruto; Nakamura, Hiroaki; Tamura, Yuichi; Imura, Kohei; Saiki, Toshiharu; Okamoto, Hiromi

    2010-01-01

    The optical properties of a gold nanorod were investigated by Imura et. al. using an apertured-type scanning near-field optical microscope (SNOM). The observed transmission image showed an oscillating pattern along the long axis of the nanorod. We obtain the image using the finite-difference time-domain (FDTD) method. Our model includes a nanorod on a glass substrate, a SNOM, and current as a light source. We develop a simple method for including the Drude-Lorentz dispersion relation of Vial et. al. for gold in the FDTD. The oscillating pattern is explained by the total current in the nanorod, tip of the SNOM, and light source. (author)

  6. Theoretical analysis of bimetallic nanorod dimer biosensors for label-free molecule detection

    Das, Avijit; Talukder, Muhammad Anisuzzaman

    2018-02-01

    In this work, we theoretically analyze a gold (Au) core within silver (Ag) shell (Au@Ag) nanorod dimer biosensor for label-free molecule detection. The incident light on an Au@Ag nanorod strongly couples to localized surface plasmon modes, especially around the tip region. The field enhancement around the tip of a nanorod or between the tips of two longitudinally aligned nanorods as in a dimer can be exploited for sensitive detection of biomolecules. We derive analytical expressions for the interactions of an Au@Ag nanorod dimer with the incident light. We also study the detail dynamics of an Au@Ag nanorod dimer with the incident light computationally using finite difference time domain (FDTD) technique when core-shell ratio, relative position of the nanorods, and angle of incidence of light change. We find that the results obtained using the developed analytical model match well with that obtained using FDTD simulations. Additionally, we investigate the sensitivity of the Au@Ag nanorod dimer, i.e., shift in the resonance wavelength, when a target biomolecule such as lysozyme (Lys), human serum albumin (HSA), anti-biotin (Abn), human catalase (CAT), and human fibrinogen (Fb) protein molecules are attached to the tips of the nanorods.

  7. Plasmon-resonant nanorods as multimodal agents for two-photon luminescent imaging and photothermal therapy

    Huff, Terry B.; Hansen, Matthew N.; Tong, Ling; Zhao, Yan; Wang, Haifeng; Zweifel, Daniel A.; Cheng, Ji-Xin; Wei, Alexander

    2007-02-01

    Plasmon-resonant gold nanorods have outstanding potential as multifunctional agents for image-guided therapies. Nanorods have large absorption cross sections at near-infrared (NIR) frequencies, and produce two-photon luminescence (TPL) when excited by fs-pulsed laser irradiation. The TPL signals can be detected with single-particle sensitivity, enabling nanorods to be imaged in vivo while passing through blood vessels at subpicomolar concentrations. Furthermore, cells labeled with nanorods become highly susceptible to photothermal damage when irradiated at plasmon resonance, often resulting in a dramatic blebbing of the cell membrane. However, the straightforward application of gold nanorods for cell-specific labeling is obstructed by the presence of CTAB, a cationic surfactant carried over from nanorod synthesis which also promotes their nonspecific uptake into cells. Careful exchange and replacement of CTAB can be achieved by introducing oligoethyleneglycol (OEG) units capable of chemisorption onto nanorod surfaces by in situ dithiocarbamate formation, a novel method of surface functionalization. Nanorods with a dense coating of methyl-terminated OEG chains are shielded from nonspecific cell uptake, whereas nanorods functionalized with folate-terminated OEG chains accumulate on the surface of tumor cells overexpressing their cognate receptor, with subsequent delivery of photoinduced cell damage at low laser fluence.

  8. An Au/Si hetero-nanorod-based biosensor for Salmonella detection

    Fu Junxue; Zhao Yiping [Physics and Astronomy Department, University of Georgia, Athens, GA 30602 (United States); Park, Bosoon; Siragusa, Greg [USDA, ARS, Russell Research Center, Athens, GA 30605 (United States); Jones, Les; Tripp, Ralph [Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602 (United States); Cho, Yong-Jin [Korea Food Research Institute, Songnam (Korea, Republic of)], E-mail: zhaoy@physast.uga.edu

    2008-04-16

    We present a novel and effective food-borne bacteria detection method. A hetero-structured silicon/gold nanorod array fabricated by the glancing angle deposition method is functionalized with anti-Salmonella antibodies and organic dye molecules. Due to the high aspect ratio nature of the Si nanorods, dye molecules attached to the Si nanorods produce an enhanced fluorescence upon capture and detection of Salmonella. This bio-functional hetero-nanorod detection method has great potential in the food safety industry as well as in biomedical diagnostics.

  9. Structural interpretation of chemically synthesized ZnO nanorod and its application in lithium ion battery

    Kundu, Samapti; Sain, Sumanta; Yoshio, Masaki; Kar, Tanusree; Gunawardhana, Nanda; Pradhan, Swapan Kumar

    2015-01-01

    Graphical abstract: - Highlights: • ZnO nanorods are synthesized at room temperature via a simple chemical route. • Growth direction of ZnO nanorods has been determined along 〈0 0 2〉. • ZnO nanorods constructed anode shows a high discharge capacity in first cycle. • It retains good reversible capacity compared to other ZnO morphologies. - Abstract: ZnO nanorods are synthesized at room temperature via a simple chemical route without using any template or capping agent and its importance is evaluated as a suitable candidate for anode material in lithium ion battery. Structural and microstructure characterizations of these nanorods are made by analyzing the X-ray diffraction data employing the Rietveld method of powder structure refinement. It reveals that the ZnO nanorods are grown up with a preferred orientation and elongated along 〈0 0 2〉. FESEM images reveal that these uniform cylindrical shaped nanorods are of different lengths and diameters. These synthesized ZnO nanorods are tested as an anode material for lithium ion batteries. The nano grain size of the ZnO rods results in less volume expansion and/or contraction during the alloying/de-alloying process and causes in good cyclability. In addition, synthesized ZnO nanorods deliver high charge/discharge capacities compared to other reported ZnO materials

  10. Structural interpretation of chemically synthesized ZnO nanorod and its application in lithium ion battery

    Kundu, Samapti; Sain, Sumanta [Materials Science Division, Department of Physics, The University of Burdwan, Golapbag, Burdwan 713104, West Bengal (India); Yoshio, Masaki [Advanced Research and Education Centre, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Kar, Tanusree [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, West Bengal (India); Gunawardhana, Nanda, E-mail: nandagunawardhana@pdn.ac.lk [International Research Centre, Senate Building, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Pradhan, Swapan Kumar, E-mail: skpradhan@phys.buruniv.ac.in [Materials Science Division, Department of Physics, The University of Burdwan, Golapbag, Burdwan 713104, West Bengal (India)

    2015-02-28

    Graphical abstract: - Highlights: • ZnO nanorods are synthesized at room temperature via a simple chemical route. • Growth direction of ZnO nanorods has been determined along 〈0 0 2〉. • ZnO nanorods constructed anode shows a high discharge capacity in first cycle. • It retains good reversible capacity compared to other ZnO morphologies. - Abstract: ZnO nanorods are synthesized at room temperature via a simple chemical route without using any template or capping agent and its importance is evaluated as a suitable candidate for anode material in lithium ion battery. Structural and microstructure characterizations of these nanorods are made by analyzing the X-ray diffraction data employing the Rietveld method of powder structure refinement. It reveals that the ZnO nanorods are grown up with a preferred orientation and elongated along 〈0 0 2〉. FESEM images reveal that these uniform cylindrical shaped nanorods are of different lengths and diameters. These synthesized ZnO nanorods are tested as an anode material for lithium ion batteries. The nano grain size of the ZnO rods results in less volume expansion and/or contraction during the alloying/de-alloying process and causes in good cyclability. In addition, synthesized ZnO nanorods deliver high charge/discharge capacities compared to other reported ZnO materials.

  11. Morphology development and oriented growth of single crystalline ZnO nanorod

    Wu Lili; Wu Youshi; Lue Wei; Wei Huiying; Shi Yuanchang

    2005-01-01

    Single crystalline ZnO nanorods were achieved by the assembly of nanocrystallines in tens of nanometer under hydrothermal conditions with the assistance of surfactant cetyltrimethylammonium bromide (CTAB). The obtained nanorod has rough surface as a result of oriented attachment growth. Transmission electron microscope (TEM) images showed the morphology evolution of the nanorod at different reaction time. Defects were observed and porous structure was left after the assembly of hundreds of nanocrystalline building blocks. Effect of pH condition on the morphology of the nanorod was also investigated

  12. Characterization of crystalline silica nanorods synthesized via a solvothermal route using polyvinylbutyral as a template

    Chen, Lin-Jer; Liao, Jiunn-Der; Chuang, Yu-Ju; Fu, Yaw-Shyan

    2011-01-01

    The preparation of crystalline silica nanorods is presented. Crystalline silica nanorods were synthesized via a simple solvothermal route using polyvinylbutyral (PVB) as a template in an autoclave with ethylenediamine as a solvent at 180 °C for 25 h. Silica nanorods with diameters in the range of 50–80 nm were obtained. The solvothermal route with a PVB template played affected the crystallization process and the growth of the silica nanorods. The as-synthesized products were characterized using X-ray diffraction, energy dispersive spectrometry, scanning electron microscopy, and transmission electron microscopy.

  13. Hydrothermal Synthesis and Biocompatibility Study of Highly Crystalline Carbonated Hydroxyapatite Nanorods

    Xue, Caibao; Chen, Yingzhi; Huang, Yongzhuo; Zhu, Peizhi

    2015-08-01

    Highly crystalline carbonated hydroxyapatite (CHA) nanorods with different carbonate contents were synthesized by a novel hydrothermal method. The crystallinity and chemical structure of synthesized nanorods were studied by Fourier transform infrared spectroscopy (FTIR), X-ray photo-electronic spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The biocompatibility of synthesized CHA nanorods was evaluated by cell viability and alkaline phosphatase (ALP) activity of MG-63 cell line. The biocompatibility evaluation results show that these CHA nanorods are biologically active apatites and potentially promising bone-substitute biomaterials for orthopedic application.

  14. The data envelopment analysis efficiency of public power suppliers. A contribution to the discussion of deregulation; Die DEA-Effizienz oeffentlicher Stromversorger. Ein Beitrag zur Deregulierungsdiskussion

    Cantner, U; Hanusch, H; Westermann, G

    1994-03-01

    The emphasis of a draft on the reform of energy legislation from the Federal Ministry of Economics and the emphasis of the general discussion is the so-called third party access and unbundling as well as the new approach to the granting of regional monopolies. In the final analysis the point of all these suggestions is to unbundle supplies and make sure that more competition creates more efficiency. This contribution looks at the empirical aspects of the problem. Some public power supply companies in Germany were selected in order to identify and describe inefficiencies of public power supply in Germany. Part two briefly describes the situation on the sector of ``public power supply`` which the emphasis on the commitment of the public. Part three describes the basics of data envelopment analysis which is then used in part 4 in order to analyse power suppliers. A distinction is made between private and public industry analysis. Part 5 contains some conclusions. (orig./UA) [Deutsch] Im Zentrum des Referentenentwurfs zur Energierechtsreform des Bundeswirtschaftsministeriums sowie in der allgemeinen Diskussion stehen der sogenannte ``third party access``, das ``unbundling`` sowie die Neuregelung der Vergabe von Gebietsmonopolen. Letztendlich geht es bei all diesen Vorschlaegen darum, die Versorgungsleistungen ganz oder teilweise (``unbundling``) aus dem Schutzwall der regulierten Gebietsmonopole herauszunehmen und damit dafuer zu sorgen, dass ueber verstaerkten Wettbewerb eine effizientere Leistungserstellung bewerkstelligt wird. Der vorliegende Beitrag moechte zu diesem Problembereich von empirischer Seite aus Stellung nehmen. Mit Hilfe ausgewaehlter Unternehmen des oeffentlichen Stromversorgungssektors in Deutschland soll untersucht werden, ob und welche Ineffizienzen bei der oeffentlichen Stromversorgung auftreten. Abschnitt 2 beschreibt kurz die Situation im Sektor ``Oeffentlichen Stromversorgung``, wobei ein Schwerpunkt dessen oeffentlicher Auftrag ist. Abschnitt

  15. Energy efficiency

    2010-01-01

    After a speech of the CEA's (Commissariat a l'Energie Atomique) general administrator about energy efficiency as a first rank challenge for the planet and for France, this publications proposes several contributions: a discussion of the efficiency of nuclear energy, an economic analysis of R and D's value in the field of fourth generation fast reactors, discussions about biofuels and the relationship between energy efficiency and economic competitiveness, and a discussion about solar photovoltaic efficiency

  16. Manipulation and Biological Applications of Gold Nanorods

    Rostro-Kohanloo, Betty Catalina

    This thesis compared anionic polyelectrolyte wrapping stabilization with poly(sodium 4-stryene-sulfonate), (PSS), polyelectrolyte and methoxy (polyethylene glycol)-thiol (mPEG(5000)-SH) strategies. From this data the critical gold nanorod (GNR) and cetyl-trimethylammonium bromide (CTAB) concentration ratio needed for GNR stabilization was determined using optical and chemical extraction methods. This was followed by functionalization with a heterobifunctional Polyethylene glycol (PEG) linker, such as a-thio-w-carboxy poly(ethylene glycol) termed t-PEG-c and carbodiimide chemistries for antibody linkage with Immunoglobulin G (IgG), and epidermal growth factor receptor (EGFR) based Human Epidermal growth factor Receptor 2 (Her2), and Cetuximab (C225) antibodies, for in vitro cancer cell targeting. Confocal, two-photon luminescence (TPL), and dark scattering microscopy, and fluorescence, zeta potential, and Nanoparticle Enzyme-linked immunosorbent assay (ELISA) were used to monitor changes to the GNR surface. An untreatable form of bladder cancer was then studied using the t-GNR-PEG-c-Ab bioconjugates with C225 antibody, which housed a glyceraldehyde-3-phosphate (GAPDH), Fluorescein isothiocyanate (FITC) labeled siRNA, termed GAPDH-siRNA-FITC, which was included within a Luciferase based plasmid. A salt based electrostatic heating method was used to trap the GAPDH-siRNA-FITC from the PEG layer by activating the PEG polymer pour point, while a laser based heating system was used for in vitro release inside cancer cells. The down regulation of the GAPDH gene was targeted by the siRNA. as GAPDH has been shown to be up-regulated in many cancers and down-regulated by chemotherapeutic drugs. Cell culture, and subsequent imaging by transmission electron microscopy (TEM), TPL and confocal microscopy were used to view the internalized conjugates, and reverse transcriptase polymerase chain reaction (RT-PCR) were used to determine if the release of the GAPDH-siRNA caused a

  17. Interstitial diffuse radiance spectroscopy of gold nanocages and nanorods in bulk muscle tissues

    Grabtchak S

    2015-02-01

    Full Text Available Serge Grabtchak,1,2 Logan G Montgomery,1 Bo Pang,3,4 Yi Wang,4,5 Chao Zhang,6,7 Zhiyuan Li,6,7 Younan Xia,4,8 William M Whelan1,91Department of Physics, University of Prince Edward Island, Charlottetown, PEI, Canada; 2Departments of Electrical and Computer Engineering, and Physics, Dalhousie University, Halifax, Canada; 3Department of Biomedical Engineering, Peking University, Beijing, People’s Republic of China; 4The Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA; 5Key Laboratory of Green Synthesis and Applications, College of Chemistry, Chongqing Normal University, Chongqing, People’s Republic of China; 6Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, People’s Republic of China; 7College of Physics and Optoelectronics, South China University of Technology, Guangzhou, People’s Republic of China; 8School of Chemistry and Biochemistry, and School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA; 9Atlantic Veterinary College, Charlottetown, PEI, CanadaAbstract: Radiance spectroscopy was applied to the interstitial detection of localized inclusions containing Au nanocages or nanorods with various concentrations embedded in porcine muscle phantoms. The radiance was quantified using a perturbation approach, which enabled the separation of contributions from the porcine phantom and the localized inclusion, with the inclusion serving as a perturbation probe of photon distributions in the turbid medium. Positioning the inclusion at various places in the phantom allowed for tracking of photons that originated from a light source, passed through the inclusion’s location, and reached a detector. The inclusions with high extinction coefficients were able to absorb nearly all photons in the range of 650–900 nm, leading to a spectrally flat radiance signal. This signal could be

  18. Laser-induced extreme magnetic field in nanorod targets

    Lécz, Zsolt; Andreev, Alexander

    2018-03-01

    The application of nano-structured target surfaces in laser-solid interaction has attracted significant attention in the last few years. Their ability to absorb significantly more laser energy promises a possible route for advancing the currently established laser ion acceleration concepts. However, it is crucial to have a better understanding of field evolution and electron dynamics during laser-matter interactions before the employment of such exotic targets. This paper focuses on the magnetic field generation in nano-forest targets consisting of parallel nanorods grown on plane surfaces. A general scaling law for the self-generated quasi-static magnetic field amplitude is given and it is shown that amplitudes up to 1 MT field are achievable with current technology. Analytical results are supported by three-dimensional particle-in-cell simulations. Non-parallel arrangements of nanorods has also been considered which result in the generation of donut-shaped azimuthal magnetic fields in a larger volume.

  19. Copper nanorod array assisted silicon waveguide polarization beam splitter.

    Kim, Sangsik; Qi, Minghao

    2014-04-21

    We present the design of a three-dimensional (3D) polarization beam splitter (PBS) with a copper nanorod array placed between two silicon waveguides. The localized surface plasmon resonance (LSPR) of a metal nanorod array selectively cross-couples transverse electric (TE) mode to the coupler waveguide, while transverse magnetic (TM) mode passes through the original input waveguide without coupling. An ultra-compact and broadband PBS compared to all-dielectric devices is achieved with the LSPR. The output ports of waveguides are designed to support either TM or TE mode only to enhance the extinction ratios. Compared to silver, copper is fully compatible with complementary metal-oxide-semiconductor (CMOS) technology.

  20. Synthesis and magnetic properties of YMnO3 nanorods

    Dhinesh Kumar, R.; Jayavel, R.

    2012-01-01

    YMnO 3 nanorods have been synthesized by hydrothermal process at 200 deg C. The hexagonal phase of as-synthesized sample was confirmed by powder X-ray diffraction (XRD) analysis. High resolution scanning electron microscope (HRSEM) and Energy Dispersive X-ray (EDX) analysis have been carried out to study the surface morphology and elements presence in the sample. The magnetic behavior of the sample was studied by vibrating sample magnetometry (VSM) technique. (author)

  1. Photothermal reshaping of gold nanorods prevents further cell death

    Takahashi, Hironobu; Niidome, Takuro; Nariai, Ayuko; Niidome, Yasuro; Yamada, Sunao

    2006-01-01

    The combined use of phosphatidylcholine passivated gold nanorods (PC-NRs) and pulsed near-infrared (near-IR) irradiation resulted in cell death. Pulsed near-IR laser irradiation also induced reshaping of PC-NRs into spherical nanoparticles. Since reshaped particles showed no absorption in the near-IR region, successive laser irradiation did not affect cells. Photo-reshaping of PC-NRs is expected to be advantageous in preventing unwanted cell damage following destruction of target cells

  2. Prominent ethanol sensing with Cr2O3 nanoparticle-decorated ZnS nanorods sensors

    Sun, Gun-Joo; Kheel, Hyejoon; Ko, Tae-Gyung; Lee, Chongmu; Kim, Hyoun Woo

    2016-08-01

    ZnS nanorods and Cr2O3 nanoparticle-decorated ZnS nanorods were synthesized by using facile hydrothermal techniques, and their ethanol sensing properties were examined. X-ray diffraction and scanning electron microscopy revealed good crystallinity and size uniformity for the ZnS nanorods. The Cr2O3 nanoparticle-decorated ZnS nanorod sensor showed a stronger response to ethanol than the pristine ZnS nanorod sensor. The responses of the pristine and the decorated nanorod sensors to 200 ppm of ethanol at 300 °C were 2.9 and 13.8, respectively. Furthermore, under these conditions, the decorated nanorod sensor showed a longer response time (23 s) and a shorter recovery time (20 s) than the pristine one did (19 and 35 s, respectively). Consequently, the total sensing time of the decorated nanorod sensor (42 s) was shorter than that of the pristine one (55 s). The decorated nanorod sensor showed excellent selectivity to ethanol over other volatile organic compound gases including acetone, methanol, benzene, and toluene whereas the pristine one failed to show selectivity to ethanol over acetone. The improved sensing performance of the decorated nanorod sensor is attributed to a modulation of the width of the conduction channel and the height of the potential barrier at the ZnS-Cr2O3 interface accompanying the adsorption and the desorption of ethanol gas, and the greater surface-to-volume ratio of the decorated nanorods which was greater than that of the pristine one due to the existence of the ZnS-Cr2O3 interface.

  3. Fabrication of graphene/titanium carbide nanorod arrays for chemical sensor application

    Fu, Chong [Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384 (China); Li, Mingji, E-mail: limingji@163.com [Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384 (China); Li, Hongji, E-mail: hongjili@yeah.net [Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, School of Chemistry & Chemical Engineering, Tianjin University of Technology, Tianjin 300384 (China); Li, Cuiping; Qu, Changqing; Yang, Baohe [Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384 (China)

    2017-03-01

    Vertically stacked graphene nanosheet/titanium carbide nanorod array/titanium (graphene/TiC nanorod array) wires were fabricated using a direct current arc plasma jet chemical vapor deposition (DC arc plasma jet CVD) method. The graphene/TiC nanorod arrays were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction spectroscopy. The TiO{sub 2} nanotube array was reduced to the TiC nanorod array, and using those TiC nanorods as nucleation sites, the vertical graphene layer was formed on the TiC nanorod surface. The multi-target response mechanisms of the graphene/TiC nanorod array were investigated for ascorbic acid (AA), dopamine (DA), uric acid (UA), and hydrochlorothiazide (HCTZ). The vertically stacked graphene sheets facilitated the electron transfer and reactant transport with a unique porous surface, high surface area, and high electron transport network of CVD graphene sheets. The TiC nanorod array facilitated the electron transfer and firmly held the graphene layer. Thus, the graphene/TiC nanorod arrays could simultaneously respond to trace biomarkers and antihypertensive drugs. - Highlights: • Vertical graphene sheets were prepared with Ti as the catalyst via a CVD method. • TiO{sub 2} nanotubes were key transition layers in the formation of the TiC nanorods. • Vertical growth mechanism of graphene products was discussed. • Biomolecules were detected to be a chemical sensor. • Response mechanism for analytes at the graphene/TiC nanorod array was discussed.

  4. Synthesis and in vitro cytotoxicity of mPEG-SH modified gold nanorods

    Didychuk, Candice L.; Ephrat, Pinhas; Belton, Michelle; Carson, Jeffrey J. L.

    2008-02-01

    Plasmon-resonant gold nanorods show great potential as an agent for contrast-enhanced biomedical imaging or for phototherapeutics. This is primarily due to the high molar extinction coefficient at the absorption maximum and the dependence of the wavelength of the absorption maximum on the aspect ratio, which is tunable in the near-infrared (NIR) during synthesis. Although gold nanorods can be produced in high-yield through the seed-mediated growth technique, the presence of residual cetyltrimethylammonium bromide (CTAB), a stabilizing surfactant required for nanorod growth, interferes with cell function and causes cytotoxicity. To overcome this potential obstacle to in vivo use, we synthesized gold nanorods and conjugated them to a methoxy (polyethylene glycol)-thiol (mPEG (5000)-SH). This approach yielded mPEG-SH modified gold nanorods with optical and morphometric properties that were similar to raw (CTAB) nanorods. Both the CTAB and mPEG-SH nanorods were tested for cytotoxicity against the HL-60 human leukemia cell line by trypan blue exclusion, and the mPEG-SH modified gold nanorods were also tested against a rat insulinoma (RIN-38) and squamous cell carcinoma (SCCVII) cell line. Cells incubated for 24 h with the mPEG-SH modified nanorods had little change in cell viability compared to cells incubated with vehicle alone. This was in contrast to cytotoxicity of CTAB nanorods on HL-60 cells. These results suggest that mPEG-SH modified gold nanorods are better suited for cell loading protocols and injection into animals and facilitate their use for imaging and phototherapeutic purposes.

  5. Fabrication of graphene/titanium carbide nanorod arrays for chemical sensor application

    Fu, Chong; Li, Mingji; Li, Hongji; Li, Cuiping; Qu, Changqing; Yang, Baohe

    2017-01-01

    Vertically stacked graphene nanosheet/titanium carbide nanorod array/titanium (graphene/TiC nanorod array) wires were fabricated using a direct current arc plasma jet chemical vapor deposition (DC arc plasma jet CVD) method. The graphene/TiC nanorod arrays were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction spectroscopy. The TiO 2 nanotube array was reduced to the TiC nanorod array, and using those TiC nanorods as nucleation sites, the vertical graphene layer was formed on the TiC nanorod surface. The multi-target response mechanisms of the graphene/TiC nanorod array were investigated for ascorbic acid (AA), dopamine (DA), uric acid (UA), and hydrochlorothiazide (HCTZ). The vertically stacked graphene sheets facilitated the electron transfer and reactant transport with a unique porous surface, high surface area, and high electron transport network of CVD graphene sheets. The TiC nanorod array facilitated the electron transfer and firmly held the graphene layer. Thus, the graphene/TiC nanorod arrays could simultaneously respond to trace biomarkers and antihypertensive drugs. - Highlights: • Vertical graphene sheets were prepared with Ti as the catalyst via a CVD method. • TiO 2 nanotubes were key transition layers in the formation of the TiC nanorods. • Vertical growth mechanism of graphene products was discussed. • Biomolecules were detected to be a chemical sensor. • Response mechanism for analytes at the graphene/TiC nanorod array was discussed.

  6. Single Nanorod Devices for Battery Diagnostics: A Case Study on LiMn 2 O 4

    Yang, Yuan

    2009-12-09

    This paper presents single nanostructure devices as a powerful new diagnostic tool for batteries with LiMn2O4 nanorod materials as an example. LiMn2O4 and Al-doped LiMn2O4 nanorods were synthesized by a two-step method that combines hydrothermal synthesis of β-MnO2 nanorods and a solid state reaction to convert them to LiMn2O4 nanorods. λ-MnO2 nanorods were also prepared by acid treatment of LiMn2O4 nanorods. The effect of electrolyte etching on these LiMn2O 4-related nanorods is investigated by both SEM and single-nanorod transport measurement, and this is the first time that the transport properties of this material have been studied at the level of an individual singlecrystalline particle. Experiments show that Al dopants reduce the dissolution of Mn3+ ions significantly and make the LiAl 0.1Mn1.9O4 nanorods much more stable than LiMn2O4 against electrolyte etching, which is reflected by the magnification of both size shrinkage and conductance decrease. These results correlate well with the better cycling performance of Al-doped LiMn 2O4 in our Li-ion battery tests: LiAl0.1Mn 1.9O4 nanorods achieve 96% capacity retention after 100 cycles at 1C rate at room temperature, and 80% at 60 °C, whereas LiMn 2O4 shows worse retention of 91% at room temperature, and 69% at 60 °C. Moreover, temperature-dependent I - V measurements indicate that the sharp electronic resistance increase due to charge ordering transition at 290 K does not appear in our LiMn2O4 nanorod samples, suggesting good battery performance at low temperature. © 2009 American Chemical Society.

  7. Gold nanorods in an oil-base formulation for transdermal treatment of type 1 diabetes in mice

    Nose, Keisuke; Pissuwan, Dakrong; Goto, Masahiro; Katayama, Yoshiki; Niidome, Takuro

    2012-05-01

    Efficient transdermal insulin delivery to the systemic circulation would bring major benefit to diabetic patients. We investigated the possibility of using gold nanorods (GNRs) that formed a complex with an edible surfactant and insulin (INS) in an oil phase to form a solid-in-oil (SO) formulation (SO-INS-GNR) for transdermal treatment of diabetes. Diabetic mice comprised the model for our study. In vitro, there was high penetration of insulin through the stratum corneum (SC) and the dermis in mouse skin treated with an SO-INS-GNR complex plus near-infrared (NIR) light irradiation. Blood glucose levels in the diabetic mice were significantly decreased after treatment with SO-INS-GNR plus irradiation. To our knowledge, this is the first study to use gold nanorods for systemic insulin delivery through the skin. The use of an SO-INS-GNR complex combined with NIR irradiation may provide the possibility of transdermal insulin delivery to diabetic patients.Efficient transdermal insulin delivery to the systemic circulation would bring major benefit to diabetic patients. We investigated the possibility of using gold nanorods (GNRs) that formed a complex with an edible surfactant and insulin (INS) in an oil phase to form a solid-in-oil (SO) formulation (SO-INS-GNR) for transdermal treatment of diabetes. Diabetic mice comprised the model for our study. In vitro, there was high penetration of insulin through the stratum corneum (SC) and the dermis in mouse skin treated with an SO-INS-GNR complex plus near-infrared (NIR) light irradiation. Blood glucose levels in the diabetic mice were significantly decreased after treatment with SO-INS-GNR plus irradiation. To our knowledge, this is the first study to use gold nanorods for systemic insulin delivery through the skin. The use of an SO-INS-GNR complex combined with NIR irradiation may provide the possibility of transdermal insulin delivery to diabetic patients. Electronic supplementary information (ESI) available. See DOI: 10

  8. Targeted destruction of murine macrophage cells with bioconjugated gold nanorods

    Pissuwan, Dakrong [University of Technology Sydney, Institute for Nanoscale Technology (Australia); Valenzuela, Stella M. [University of Technology Sydney, Department of Medical and Molecular Biosciences (Australia)], E-mail: stella.valenzuela@uts.edu.au; Killingsworth, Murray C. [Sydney South West Pathology Service (Australia)], E-mail: murray.killingsworth@swsahs.nsw.gov.au; Xu, Xiaoda; Cortie, Michael B. [University of Technology Sydney, Institute for Nanoscale Technology (Australia)], E-mail: michael.cortie@uts.edu.au

    2007-12-15

    Gold nanorods manifest a readily tunable longitudinal plasmon resonance with light and consequently have potential for use in photothermal therapeutics. Recent work by others has shown how gold nanoshells and rods can be used to target cancer cells, which can then be destroyed using relatively high power laser radiation ({approx}1x10{sup 5} to 1x10{sup 10} W/m{sup 2}). Here we extend this concept to demonstrate how gold nanorods can be modified to bind to target macrophage cells, and show that high intensity laser radiation is not necessary, with even 5x10{sup 2} W/m{sup 2} being sufficient, provided that a total fluence of {approx}30 J/cm{sup 2} is delivered. We used the murine cell line RAW 264.7 and the monoclonal antibody CD11b, raised against murine macrophages, as our model system and a 5 mW solid state diode laser as our energy source. Exposure of the cells labeled with gold nanorods to a laser fluence of 30 J/cm{sup 2} resulted in 81% cell death compared to only 0.9% in the control, non-labeled cells.

  9. Targeted destruction of murine macrophage cells with bioconjugated gold nanorods

    Pissuwan, Dakrong; Valenzuela, Stella M.; Killingsworth, Murray C.; Xu, Xiaoda; Cortie, Michael B.

    2007-12-01

    Gold nanorods manifest a readily tunable longitudinal plasmon resonance with light and consequently have potential for use in photothermal therapeutics. Recent work by others has shown how gold nanoshells and rods can be used to target cancer cells, which can then be destroyed using relatively high power laser radiation (˜1×105 to 1×1010 W/m2). Here we extend this concept to demonstrate how gold nanorods can be modified to bind to target macrophage cells, and show that high intensity laser radiation is not necessary, with even 5×102 W/m2 being sufficient, provided that a total fluence of ˜30 J/cm2 is delivered. We used the murine cell line RAW 264.7 and the monoclonal antibody CD11b, raised against murine macrophages, as our model system and a 5 mW solid state diode laser as our energy source. Exposure of the cells labeled with gold nanorods to a laser fluence of 30 J/cm2 resulted in 81% cell death compared to only 0.9% in the control, non-labeled cells.

  10. Targeted destruction of murine macrophage cells with bioconjugated gold nanorods

    Pissuwan, Dakrong; Valenzuela, Stella M.; Killingsworth, Murray C.; Xu, Xiaoda; Cortie, Michael B.

    2007-01-01

    Gold nanorods manifest a readily tunable longitudinal plasmon resonance with light and consequently have potential for use in photothermal therapeutics. Recent work by others has shown how gold nanoshells and rods can be used to target cancer cells, which can then be destroyed using relatively high power laser radiation (∼1x10 5 to 1x10 10 W/m 2 ). Here we extend this concept to demonstrate how gold nanorods can be modified to bind to target macrophage cells, and show that high intensity laser radiation is not necessary, with even 5x10 2 W/m 2 being sufficient, provided that a total fluence of ∼30 J/cm 2 is delivered. We used the murine cell line RAW 264.7 and the monoclonal antibody CD11b, raised against murine macrophages, as our model system and a 5 mW solid state diode laser as our energy source. Exposure of the cells labeled with gold nanorods to a laser fluence of 30 J/cm 2 resulted in 81% cell death compared to only 0.9% in the control, non-labeled cells

  11. Voltammetry of Organic Pollutants on FeOOH Nanorods

    Zhang, Yuanyuan; Wan, Qijin; Yang, Nianjun

    2017-01-01

    FeOOH nanorods synthesized using a solvothermal approach have been employed to investigate the electrochemistry of organic pollutions, including ponceau 4R (PR), sunset yellow (SY), and tetrabromobisphenol A (TBBPA). The as-prepared FeOOH nanorods have been characterized using scanning electron microscopes (SEM), transmission electron microscope (TEM), X-ray photoelectron spectrometry, Brunauer-Emmett-Teller measurements, and electrochemical techniques. The modified electrode based on FeOOH nanorods exhibits a porous and net-like structure, resulting in a high surface area and many reactive/adsorption sites for soluble compounds. On this modified electrode, fast electron transfer processes of redox probes have been achieved. Electrochemistry of PR, SY, and TBBPA has been studied in detail using voltammetry, impedance, and chronocoulometry. The sensitive monitoring of both individual and total concentrations of three organic pollutions has been realized. The detection limits are 0.2, 1.0, and 0.55 nM for PR, SY, and TBBPA, respectively. Such an electrode is then promising for the electrochemical investigation and analysis of organic pollutions in different environments.

  12. Nanorod mediated collagen scaffolds as extra cellular matrix mimics

    Vedhanayagam, Mohan; Nair, Balachandran Unni; Sreeram, Kalarical Janardhanan; Mohan, Ranganathan

    2015-01-01

    Creating collagen scaffolds that mimic extracellular matrices without using toxic exogenous materials remains a big challenge. A new strategy to create scaffolds through end-to-end crosslinking through functionalized nanorods leading to well-designed architecture is presented here. Self-assembled scaffolds with a denaturation temperature of 110 °C, porosity of 70%, pore size of 0.32 μm and Young’s modulus of 231 MPa were developed largely driven by imine bonding between 3-mercapto-1-propanal (MPA) functionalized ZnO nanorods and collagen. The mechanical properties obtained were much higher than that of native collagen, collagen—MPA, collagen—3-mercapto-1-propanol (3MPOH) or collagen- 3-MPOH-ZnO, clearly bringing out the relevance of nanorod mediated assembly of fibrous networks. This new strategy has led to scaffolds with mechanical properties much higher than earlier reports and can provide support for cell growth and facilitation of cell attachment. (paper)

  13. Confinement and Ordering of Au Nanorods in Polymer Films

    Hore, Michael J. A.; Mills, Eric; Liu, Yu; Composto, Russell J.

    2009-03-01

    Ordered arrays of gold nanorods (Au NRs) possess interesting optical properties that might be utilized in future devices. Au NRs functionalized with a poly(ethylene glycol)-thiol brush are incorporated into homopolymer or block copolymer (BCP) films. NR distribution and orientational correlations are studied as a function of nanorod concentration and spacial confinement via Rutherford backscattering spectrometry (RBS) and transmission electron microscopy, respectively. In particular, differences in the degree of nanorod ordering are presented for PMMA homopolymer films (d ˜ 45 nm) versus PS-b-PMMA BCP films (L/2 ˜ 40 nm), where higher ordering is seen in the case of BCP films. At moderate volume fractions of NRs, φ = 1% to 10%, the degree of ordering is moderate, and increases with increasing φ . However, coexistence between regions of higher ordering and isotropic orientations is observed. In addition to the planar confinement considered above, orientation of Au NRs confined to cylindrical P2VP domains is studied in PS-b-P2VP BCP films.

  14. Unique temporal and spatial biomolecular emission profile on individual zinc oxide nanorods

    Singh, Manpreet; Song, Sheng; Hahm, Jong-In

    2013-12-01

    Zinc oxide nanorods (ZnO NRs) have emerged in recent years as extremely useful, optical signal-enhancing platforms in DNA and protein detection. Although the use of ZnO NRs in biodetection has been demonstrated so far in systems involving many ZnO NRs per detection element, their future applications will likely take place in a miniaturized setting while exploiting single ZnO NRs in a low-volume, high-throughput bioanalysis. In this paper, we investigate temporal and spatial characteristics of the biomolecular fluorescence on individual ZnO NR systems. Quantitative and qualitative examinations of the biomolecular intensity and photostability are carried out as a function of two important criteria, the time and position along the long axis (length) of NRs. Photostability profiles are also measured with respect to the position on NRs and compared to those characteristics of biomolecules on polymeric control platforms. Unlike the uniformly distributed signal observed on the control platforms, both the fluorescence intensity and photostability are position-dependent on individual ZnO NRs. We have identified a unique phenomenon of highly localized, fluorescence intensification on the nanorod ends (FINE) of well-characterized, individual ZnO nanostructures. When compared to the polymeric controls, the biomolecular fluorescence intensity and photostability are determined to be higher on individual ZnO NRs regardless of the position on NRs. We have also carried out finite-difference time-domain simulations the results of which are in good agreement with the observed FINE. The outcomes of our investigation will offer a much needed basis for signal interpretation for biodetection devices and platforms consisting of single ZnO NRs and, at the same time, contribute significantly to provide insight in understanding the biomolecular fluorescence observed from ZnO NR ensemble-based systems.Zinc oxide nanorods (ZnO NRs) have emerged in recent years as extremely useful, optical

  15. Electrodeposition of hierarchical ZnO nanorod arrays on flexible stainless steel mesh for dye-sensitized solar cell

    Lu, Hui; Zhai, Xiangyang; Liu, Wenwu; Zhang, Mei; Guo, Min, E-mail: guomin@ustb.edu.cn

    2015-07-01

    Hierarchical ZnO nanorod arrays (ZNRAs) were synthesized on flexible stainless steel mesh (SSM) in large scale by a two-step facile electrodeposition method. The structure and morphology of the as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The growth mechanism of the ZnO hierarchical nanostructures was also discussed. Moreover, the effect of ZnO morphology on the photovoltaic performance of the flexible DSSCs based on SSM supported ZnO nanostructures was investigated in detail. It is shown that the flexible DSSCs exhibited a relatively higher power conversion efficiency of 1.11% compared with that based on primary ZNRAs. - Highlights: • Hierarchical ZnO nanorod arrays (ZNRAs) were prepared by electrodeposition method. • Flexible stainless steel mesh (SSM) supported with hierarchical ZNRAs was first used for DSSCs. • The effect of ZnO morphology on the photovoltaic performance of flexible DSSCs was investigated. • The DSSC based on 3-Hierarchical ZNRAs/ZNPs showed a relatively efficiency of 1.11%.

  16. Role of bonding mechanisms during transfer hydrogenation reaction on heterogeneous catalysts of platinum nanoparticles supported on zinc oxide nanorods

    Al-Alawi, Reem A.; Laxman, Karthik; Dastgir, Sarim; Dutta, Joydeep

    2016-07-01

    For supported heterogeneous catalysis, the interface between a metal nanoparticle and the support plays an important role. In this work the dependency of the catalytic efficiency on the bonding chemistry of platinum nanoparticles supported on zinc oxide (ZnO) nanorods is studied. Platinum nanoparticles were deposited on ZnO nanorods (ZnO NR) using thermal and photochemical processes and the effects on the size, distribution, density and chemical state of the metal nanoparticles upon the catalytic activities are presented. The obtained results indicate that the bonding at Pt-ZnO interface depends on the deposition scheme which can be utilized to modulate the surface chemistry and thus the activity of the supported catalysts. Additionally, uniform distribution of metal on the catalyst support was observed to be more important than the loading density. It is also found that oxidized platinum Pt(IV) (platinum hydroxide) provided a more suitable surface for enhancing the transfer hydrogenation reaction of cyclohexanone with isopropanol compared to zero valent platinum. Photochemically synthesized ZnO supported nanocatalysts were efficient and potentially viable for upscaling to industrial applications.

  17. Self-Assembly of ZnO-Nanorods and Its Performance in Quasi Solid Dye Sensitized Solar Cells

    Aprilia, A.; Erdienzy, A.; Bahtiar, A.; Safriani, L.; Syakir, N.; Risdiana; Saragi, T.; Hidayat, S.; Fitrilawati; Hidayat, R.; Siregar, R. E.

    2017-07-01

    Zinc oxide (ZnO) nanorods (NRs) were successfully prepared by self-assembly methods using zinc nitrate hexahydrate and hexamethylenetetramine as raw materials. ZnO-NRs were grown on FTO/ZnO seed layer and to enhance dye adsorption it was continued by deposition of titania (TiO2) paste by screen printing method. Deposition time of ZnO-NRs were varied, for 120, 150 and 180 minutes and subsequently stacked with one layer of TiO2 mesoporous. The resulting heterojunction layers of FTO/ZnO-Nrs/TiO2 was then applied as a photoanode in quasi-solid dye sensitized solar cell (QS- DSSC) with polymer gel electrolyte (PGE) as a hole conductor. UV-Vis spectrometer was used to investigate the changes of dye adsorption in photoanode with/without inserting titania mesoporous. Characterizations of scanning electron microscopy (SEM) and X-ray diffraction was carried out and the results shows that increasing the deposition time produces a smaller average grain size, diameter and denser layer of ZnO-nanorods. From current-voltage measurement, higher efficiency (η = 2.53%) was obtained for 120 min ZnO nanorods with short circuit current density (Jsc ) of 2.84 mA/cm2 and open circuit voltage (Voc) of 0.7 V. The combination of TiO2 and ZnO-NRs shows a better performance in solar cells characteristics due to increases of dye adsorption on photoanode and high photogenerated electron transport rate. This work emphasizes an optimum condition of ZnO-NRs in combination with TiO2 mesoporous as an alternative photoanode in QS-DSSC.

  18. Redox Additive-Improved Electrochemically and Structurally Robust Binder-Free Nickel Pyrophosphate Nanorods as Superior Cathode for Hybrid Supercapacitors.

    Sankar, Kalimuthu Vijaya; Seo, Youngho; Lee, Su Chan; Chan Jun, Seong

    2018-03-07

    For several decades, one of the great challenges for constructing a high-energy supercapacitor has been designing electrode materials with high performance. Herein, we report for the first time to our knowledge a novel hybrid supercapacitor composed of battery-type nickel pyrophosphate one-dimensional (1D) nanorods and capacitive-type N-doped reduced graphene oxide as the cathode and anode, respectively, in an aqueous redox-added electrolyte. More importantly, ex situ microscopic images of the nickel pyrophosphate 1D nanorods revealed that the presence of the battery-type redox additive enhanced the charge storage capacity and cycling life as a result of the microstructure stability. The nickel pyrophosphate 1D nanorods exhibited their maximum specific capacitance (8120 mF cm -2 at 5 mV s -1 ) and energy density (0.22 mWh cm -2 at a power density of 1.375 mW cm -2 ) in 1 M KOH + 75 mg K 3 [Fe(CN) 6 ] electrolyte. On the other side, the N-doped reduced graphene oxide delivered an excellent electrochemical performance, demonstrating that it was an appropriate anode. A hybrid supercapacitor showed a high specific capacitance (224 F g -1 at a current density of 1 A g -1 ) and high energy density (70 Wh kg -1 at a power density of 750 W kg -1 ), as well as a long cycle life (a Coulombic efficiency of 96% over 5000 cycles), which was a higher performance than most of those in recent reports. Our results suggested that the materials and redox additive in this novel design hold great promise for potential applications in a next-generation hybrid supercapacitor.

  19. SERS active Ag encapsulated Fe@SiO2 nanorods in electromagnetic wave absorption and crystal violet detection.

    Senapati, Samarpita; Srivastava, Suneel Kumar; Singh, Shiv Brat; Kulkarni, Ajit R

    2014-11-01

    The present work is focused on the preparation of Fe nanorods by the chemical reduction of FeCl3 (aq) using NaBH4 in the presence of glycerol as template followed by annealing of the product at 500°C in the presence of H2 gas flow. Subsequently, its surface has been modified by silica followed by silver nanoparticles to form silica coated Fe (Fe@SiO2) and Ag encapsulated Fe@SiO2 nanostructure employing the Stöber method and silver mirror reaction respectively. XRD pattern of the products confirmed the formation of bcc phase of iron and fcc phase of silver, though silica remained amorphous. FESEM images established the growth of iron nanorods from the annealed product and also formation of silica and silver coating on its surface. The appearance of the characteristics bands in FTIR confirmed the presence of SiO2 on the Fe surface. Magnetic measurements at room temperature indicated the ferromagnetic behavior of as prepared iron nanorods, Fe@SiO2 and silver encapsulated Fe@SiO2 nanostructures. All the samples exhibited strong microwave absorption property in the high frequency range (10GHz), though it is superior for Ag encapsulated Fe@SiO2 (-14.7dB) compared with Fe@SiO2 (-9.7dB) nanostructures of the same thickness. The synthesized Ag encapsulated Fe@SiO2 nanostructure also exhibited the SERS phenomena, which is useful in the detection of the carcinogenic dye crystal violet (CV) upto the concentration of 10(-10)M. All these findings clearly demonstrate that the Ag encapsulated Fe@SiO2 nanostructure could efficiently be used in the environmental remediation. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Photoluminescence study of CdSe nanorods embedded in a PVA matrix

    Sharma, Mamta [Centre of Advanced Study in Physics, Department of Physics, Panjab University, Chandigarh 160014 (India); Tripathi, S.K., E-mail: surya@pu.ac.in [Centre of Advanced Study in Physics, Department of Physics, Panjab University, Chandigarh 160014 (India)

    2013-03-15

    Nanometer-sized semiconductor CdSe nanorods have been successfully grown within polyvinyl alcohol (PVA) matrix by in situ technique. PVA:n-CdSe nanorods are characterized by X-ray diffraction, transmission electron microscopy, UV-vis spectrophotometer and photoluminescence spectroscopy. The photoluminescence spectra of PVA:n-CdSe nanorods are studied at different excitation wavelengths. PVA:n-CdSe nanorods have demonstrated to exhibit strong and well-defined green photoluminescence emission. The long-term stability of the PL properties of PVA:n-CdSe nanorods is also investigated in view of possible applications of polymer nanocomposites. The linear optical constants such as the extinction coefficient (k), real ({epsilon}{sub 1}) and imaginary ({epsilon}{sub 2}) dielectric constant, optical conductivity ({sigma}{sub opt}) are calculated for PVA:n-CdSe nanorods. The optical properties i.e. good photostability and larger stokes shift suggesting to apply PVA:n-CdSe nanorods in bioimaging applications. - Highlights: Black-Right-Pointing-Pointer In situ synthesis of PVA:n-CdSe via chemical bath method at room temperature. {open_square} From TEM image, the three arm nanorods morphology of PVA:n-CdSe is obtained. Black-Right-Pointing-Pointer The optical constants i.e. n, k, {epsilon}{sub 1}, {epsilon}{sub 2} and {sigma}{sub opt} are calculated. Black-Right-Pointing-Pointer Exhibiting green band photoemission peak at 540 nm.

  1. Thousand-fold enhancement of single-molecule fluorescence near a single gold nanorod

    Yuan, H.; Khatua, S.; Zijlstra, P.; Yorulmaz, M.; Orrit, M.

    2013-01-01

    Single molecules: Large enhancements of single-molecule fluorescence up to 1100 times by using synthesized gold nanorods are reported (see picture). This high enhancement is achieved by selecting a dye with its adsorption and emission close to the surface plasmon resonance of the gold nanorods

  2. Large-scale syntheses of uniform ZnO nanorods and ethanol gas sensors application

    Chen Jin; Li Jin; Li Jiahui; Xiao Guoqing; Yang Xiaofeng

    2011-01-01

    Research highlights: → The uniform ZnO nanorods could be synthesized by a low temperature, solution-based method. → The results showed that the sample had uniform rod-like morphology with a narrow size distribution and highly crystallinity. → Room-temperature photoluminescence spectra of these nanorods show an exciton emission around 382 nm and a weak deep level emission, indicating the nanorods have high quality. → The sensor exhibited high sensitivity and fast response to ethanol gas at a work temperature of 400 deg. C. - Abstract: Uniform ZnO nanorods with a gram scale were prepared by a low temperature and solution-based method. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL). The results showed that the sample had uniform rod-like morphology with a narrow size distribution and highly crystallinity. Room-temperature PL spectra of these nanorods show an exciton emission around 382 nm and a negligible deep level emission, indicating the nanorods have high quality. The gas-sensing properties of the materials have been investigated. The results indicate that the as-prepared nanorods show much better sensitivity and stability. The n-type semiconductor gas sensor exhibited high sensitivity and fast response to ethanol gas at a work temperature of 400 deg. C. ZnO nanorods are excellent potential candidates for highly sensitive gas sensors and ultraviolet laser.

  3. Directed self-assembly of nanorod networks: bringing the top down to the bottom up

    Einsle, Joshua F; Scheunert, Gunther; Murphy, Antony; Pollard, Robert; Bowman, Robert M; McPhillips, John; Zayats, Anatoly V

    2012-01-01

    Self-assembled electrodeposited nanorod materials have been shown to offer an exciting landscape for a wide array of research ranging from nanophotonics through to biosensing and magnetics. However, until now, the scope for site-specific preparation of the nanorods on wafers has been limited to local area definition. Further there is little or no lateral control of nanorod height. In this work we present a scalable method for controlling the growth of the nanorods in the vertical direction as well as their lateral position. A focused ion beam pre-patterns the Au cathode layer prior to the creation of the anodized aluminium oxide (AAO) template on top. When the pre-patterning is of the same dimension as the pore spacing of the AAO template, lines of single nanorods are successfully grown. Further, for sub-200 nm wide features, a relationship between the nanorod height and distance from the non-patterned cathode can be seen to follow a quadratic growth rate obeying Faraday’s law of electrodeposition. This facilitates lateral control of nanorod height combined with localized growth of the nanorods. (paper)

  4. Directed self-assembly of nanorod networks: bringing the top down to the bottom up.

    Einsle, Joshua F; Scheunert, Gunther; Murphy, Antony; McPhillips, John; Zayats, Anatoly V; Pollard, Robert; Bowman, Robert M

    2012-12-21

    Self-assembled electrodeposited nanorod materials have been shown to offer an exciting landscape for a wide array of research ranging from nanophotonics through to biosensing and magnetics. However, until now, the scope for site-specific preparation of the nanorods on wafers has been limited to local area definition. Further there is little or no lateral control of nanorod height. In this work we present a scalable method for controlling the growth of the nanorods in the vertical direction as well as their lateral position. A focused ion beam pre-patterns the Au cathode layer prior to the creation of the anodized aluminium oxide (AAO) template on top. When the pre-patterning is of the same dimension as the pore spacing of the AAO template, lines of single nanorods are successfully grown. Further, for sub-200 nm wide features, a relationship between the nanorod height and distance from the non-patterned cathode can be seen to follow a quadratic growth rate obeying Faraday's law of electrodeposition. This facilitates lateral control of nanorod height combined with localized growth of the nanorods.

  5. Facile formation of ZIF-8 thin films on ZnO nanorods

    Al-Kutubi, H.; Dikhtiarenko, A.; Zafarani, H.R.; Sudhölter, E.J.R.; Gascon, J.; Rassaei, L.

    2015-01-01

    In this work, thin films of the well-known metal–organic framework ZIF-8 were formed on zinc oxide nanorods through the reaction with 2-methyl-imidazole solution (Hmim). Deposition of a thin film of the linker solution allows the underlying zinc oxide nanorod morphology to be preserved, resulting in

  6. Growth of vertically aligned ZnO nanorods using textured ZnO films

    Meléndrez Manuel

    2011-01-01

    Full Text Available Abstract A hydrothermal method to grow vertical-aligned ZnO nanorod arrays on ZnO films obtained by atomic layer deposition (ALD is presented. The growth of ZnO nanorods is studied as function of the crystallographic orientation of the ZnO films deposited on silicon (100 substrates. Different thicknesses of ZnO films around 40 to 180 nm were obtained and characterized before carrying out the growth process by hydrothermal methods. A textured ZnO layer with preferential direction in the normal c-axes is formed on substrates by the decomposition of diethylzinc to provide nucleation sites for vertical nanorod growth. Crystallographic orientation of the ZnO nanorods and ZnO-ALD films was determined by X-ray diffraction analysis. Composition, morphologies, length, size, and diameter of the nanorods were studied using a scanning electron microscope and energy dispersed x-ray spectroscopy analyses. In this work, it is demonstrated that crystallinity of the ZnO-ALD films plays an important role in the vertical-aligned ZnO nanorod growth. The nanorod arrays synthesized in solution had a diameter, length, density, and orientation desirable for a potential application as photosensitive materials in the manufacture of semiconductor-polymer solar cells. PACS 61.46.Hk, Nanocrystals; 61.46.Km, Structure of nanowires and nanorods; 81.07.Gf, Nanowires; 81.15.Gh, Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.

  7. Synthesis of 1-D ZnO nanorods and polypyrrole/1-D ZnO ...

    1-D ZnO nanorods and PPy/1-D ZnO nanocomposites were prepared by the surfactant-assisted precipitation and in situ polymerization method, respectively. The synthesized nanorods and nanocomposites were characterized by UV–Vis spectrophotometer, Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction ...

  8. Structural and Optical Properties of Eu Doped ZnO Nanorods prepared by Pulsed Laser Deposition

    Alarawi, Abeer

    2014-06-23

    Nano structured wide band gap semiconductors have attracted attention of many researchers due to their potential electronic and optoelectronic applications. In this thesis, we report successful synthesis of well aligned Eu doped ZnO nano-rods prepared, for the first time to our knowledge, by pulsed laser deposition (PLD) without any catalyst. X-ray diffraction (XRD) patterns shows that these Eu doped ZnO nanorods are grown along the c-axis of ZnO wurtzite structure. We have studied the effect of the PLD growth conditions on forming vertically aligned Eu doped ZnO nanorods. The structural properties of the material are investigated using a -scanning electron microscope (SEM). The PLD parameters must be carefully controlled in order to obtain c-axis oriented ZnO nanorods on sapphire substrates, without the use of any catalyst. The experiments conducted in order to identify the optimal growth conditions confirmed that, by adjusting the target-substrate distance, substrate temperature, laser energy and deposition duration, the nanorod size could be successfully controlled. Most importantly, the results indicated that the photoluminescence (PL) properties reflect the quality of the ZnO nanorods. These parameters can change the material’s structure from one-dimensional to two-dimensional however the laser energy and frequency affect the size and the height of the nanorods; the xygen pressure changes the density of the nanorods.

  9. Effect of ALD surface treatment on structural and optical properties of ZnO nanorods

    Jang, Jin-Tak [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Ryu, Hyukhyun, E-mail: hhryu@inje.ac.kr [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Lee, Won-Jae [Department of Materials and Components Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of)

    2013-07-01

    In this study, we report on the improvement of the optical and structural properties of ZnO nanorods using atomic layer deposition (ALD) on seed ZnO nanorods. After the initial growth of ZnO seed nanorods by hydrothermal synthesis for 1 h, a ZnO layer with a thickness of 10 nm was deposited on the initial ZnO seed nanorods using ALD. Then ZnO was further grown by hydrothermal synthesis for 4 h. The samples were characterized using room temperature photoluminescence (PL), field emission-scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). From this experiment, it was found that the ZnO nanorods with the ALD surface treatment show improved optical and structural properties when compared with the ZnO nanorods grown only by hydrothermal synthesis. The ZnO nanorods with the ALD surface treatment show about 2.7 times higher XRD (0 0 2) peak intensity, about 2.64 times higher PL NBE peak intensity, and about 3.1 times better NBE/DLE ratio than the ZnO nanorods without an ALD surface treatment.

  10. Coating fabrics with gold nanorods for colouring, UV-protection, and antibacterial functions

    Zheng, Yidan; Xiao, Manda; Jiang, Shouxiang; Ding, Feng; Wang, Jianfang

    2012-12-01

    Gold nanorods exhibit rich colours owing to the nearly linear dependence of the longitudinal plasmon resonance wavelength on the length-to-diameter aspect ratio. This property of Au nanorods has been utilized in this work for dyeing fabrics. Au nanorods of different aspect ratios were deposited on both cotton and silk fabrics by immersing them in Au nanorod solutions. The coating of Au nanorods makes the fabrics exhibit a broad range of colours varying from brownish red through green to purplish red, which are essentially determined by the longitudinal plasmon wavelength of the deposited Au nanorods. The colorimetric values of the coated fabrics were carefully measured for examining the colouring effects. The nanorod-coated cotton fabrics were found to be commercially acceptable in washing fastness to laundering tests and colour fastness to dry cleaning tests. Moreover, the nanorod-coated cotton and silk fabrics show significant improvements on both UV-protection and antibacterial functions. Our study therefore points out a promising approach for the use of noble metal nanocrystals as dyeing materials for textile applications on the basis of their inherent localized plasmon resonance properties.

  11. Fast vertical growth of ZnO nanorods using a modified chemical bath deposition

    Lee, Tae-hyun [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Ryu, Hyukhyun, E-mail: hhryu@inje.ac.kr [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Lee, Won-Jae [Department of Materials and Components Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of)

    2014-06-01

    Highlights: • We grew vertical ZnO nanorods by a modified CBD process with a fast growth rate. • We studied the effects of the CBD process by varying growth temperature, time, and concentration. • The ZnO nanorods grown by the modified CBD showed good morphological and structural properties. - Abstract: In this study, we grew vertical ZnO nanorods on seeded Si (1 0 0) substrates using a modified chemical bath deposition (CBD). We investigated the effects of the growth temperature, growth time and concentration on the morphological and structural properties of the ZnO nanorods using field emission gun scanning electron microscopy (FEG-SEM) and X-ray diffraction. This modified CBD method shows improved results over conventional CBD. ZnO nanorods with good structural XRD properties were grown with a very fast growth rate in a wide range of growth conditions and did not require post-growth annealing.

  12. Oxide nano-rod array structure via a simple metallurgical process

    Nanko, M; Do, D T M

    2011-01-01

    A simple method for fabricating oxide nano-rod array structure via metallurgical process is reported. Some dilute alloys such as Ni(Al) solid solution shows internal oxidation with rod-like oxide precipices during high-temperature oxidation with low oxygen partial pressure. By removing a metal part in internal oxidation zone, oxide nano-rod array structure can be developed on the surface of metallic components. In this report, Al 2 O 3 or NiAl 2 O 4 nano-rod array structures were prepared by using Ni(Al) solid solution. Effects of Cr addition into Ni(Al) solid solution on internal oxidation were also reported. Pack cementation process for aluminizing of Ni surface was applied to prepare nano-rod array components with desired shape. Near-net shape Ni components with oxide nano-rod array structure on their surface can be prepared by using the pack cementation process and internal oxidation,

  13. Synthesis and microstructural characterization of growth direction controlled ZnO nanorods using a buffer layer

    Park, Dong Jun; Kim, Dong Chan; Lee, Jeong Yong; Cho, Hyung Koun

    2006-01-01

    The growth direction and morphology of one-dimensional ZnO nanostructures grown by metal-organic chemical vapour deposition (MOCVD) were modulated by changing the growth temperature of previously deposited ZnO buffer layers that were used as a template. The ZnO nanorods grown on the low-temperature deposited buffer layer were regularly inclined with respect to the substrate surface and show in-plane alignment with azimuthally six-fold symmetry. In contrast, deposition of the buffer layer at higher growth temperature led to the formation of vertically well-aligned ZnO nanorods. In addition, the ZnO nanorods grown on the buffer layer deposited at low growth temperature show a growth direction of [1 0 1-bar 0], unlike the conventional ZnO nanorods showing a growth direction of [0001]. The microstructural analysis and atomic modelling of the formation of regularly inclined nanorods using transmission electron microscopy are presented

  14. Synchrotron X-ray Scattering of ZnO Nanorods: Periodic Ordering and Lattice Size

    Zhu, Z.; Andelman, T.; Yin, M.; Chen, T.; Ehrlich, S.; O'Brien, S.; Osgood, Jr. R.

    2005-01-01

    We demonstrate that synchrotron x-ray powder diffraction (XRD) is a powerful technique for studying the structure and self-organization of zinc-oxide nanostructures. Zinc-oxide nanorods were prepared by a solution-growth method that resulted in uniform nanorods with 2-nm diameter and lengths in the range 10-50 nm. These nanorods were structurally characterized by a combination of small-angle and wide-angle synchrotron XRD and transmission electron microscopy (TEM). Small-angle XRD and TEM were used to investigate nanorod self-assembly and the influence of surfactant/precursor ratio on self-assembly. Wide-angle XRD was used to study the evolution of nanorod growth as a function of synthesis time and surfactant/precursor ratio

  15. Characterization of individual barium titanate nanorods and their assessment as building blocks of new circuit architectures

    Zagar, Kristina; Recnik, Aleksander; Ceh, Miran; Hernandez-Ramirez, Francisco; Morante, Joan Ramon; Prades, Joan Daniel

    2011-01-01

    In this work, we report on the integration of individual BaTiO 3 nanorods into simple circuit architectures. Polycrystalline BaTiO 3 nanorods were synthesized by electrophoretic deposition (EPD) of barium titanate sol into aluminium oxide (AAO) templates and subsequent annealing. Transmission electron microscopy (TEM) observations revealed the presence of slabs of hexagonal polymorphs intergrown within cubic grains, resulting from the local reducing atmosphere during the thermal treatment. Electrical measurements performed on individual BaTiO 3 nanorods revealed resistivity values between 10 and 100 Ω cm, which is in good agreement with typical values reported in the past for oxygen-deficient barium titanate films. Consequently the presence of oxygen vacancies in their structure was indirectly validated. Some of these nanorods were tested as proof-of-concept humidity sensors. They showed reproducible responses towards different moisture concentrations, demonstrating that individual BaTiO 3 nanorods may be integrated in complex circuit architectures with functional capacities.

  16. Synthesis of uniform-sized bimetallic iron-nickel phosphide nanorods

    Yoon, Ki Youl; Jang, Youngjin; Park, Jongnam; Hwang, Yosun; Koo, Bonil; Park, Je-Geun; Hyeon, Taeghwan

    2008-01-01

    We synthesized uniform-sized nanorods of iron-nickel phosphides from the thermal decomposition of metal-phosphine complexes. Uniform-sized (Fe x Ni 1-x ) 2 P nanorods (0≤x≤1) of various compositions were synthesized by thermal decomposition of Ni-trioctylphosphine (TOP) complex and Fe-TOP complex. By measuring magnetic properties, we found that blocking temperature and coercive field depend on Ni content in the nanorods. Both parameters were more sensitive to doping compared with bulk samples. - Graphical abstract: We synthesized uniform-sized nanorods of iron-nickel phosphides from thermal decomposition of metal-phosphine complexes. The magnetic studies showed that blocking temperature and coercive field depend on Ni content in the nanorods

  17. Hydrothermally grown ZnO nanorods on self-source substrate and their field emission

    Liu, J P; Xu, C X; Zhu, G P; Li, X; Cui, Y P; Yang, Y; Sun, X W

    2007-01-01

    Vertically aligned zinc oxide nanorod arrays were grown directly using a zinc foil as both source and substrate in pure water at low temperature by a simple hydrothermal reaction. The morphology and crystal structure of the ZnO nanorod arrays were examined by scanning electron microscopy, transmission electron microscopy and x-ray diffraction, respectively. The nanorods grew along the [0 0 0 1] direction and were 80 nm in diameter and almost 2 μm in length. Directly employing the zinc foil substrate as cathode, the field emission (FE) of the ZnO nanorods presented a two-stage slope behaviour in a ln(J/E 2 )-1/E plot according to the Fowler-Nordheim equation. The FE behaviour was investigated by considering the action of the defects in ZnO nanorods based on the measurement of the photoluminescence

  18. Spin-dependent tunneling transport into CrO2 nanorod devices with nonmagnetic contacts.

    Song, Yipu; Schmitt, Andrew L; Jin, Song

    2008-08-01

    Single-crystal nanorods of half-metallic chromium dioxide (CrO2) were synthesized and structurally characterized. Spin-dependent electrical transport was investigated in individual CrO2 nanorod devices contacted with nonmagnetic metallic electrodes. Negative magnetoresistance (MR) was observed at low temperatures due to the spin-dependent direct tunneling through the contact barrier and the high spin polarization in the half-metallic nanorods. The magnitude of this negative magnetoresistance decreases with increasing bias voltage and temperature due to spin-independent inelastic hopping through the barrier, and a small positive magnetoresistance was found at room temperature. It is believed that the contact barrier and the surface state of the nanorods have great influence on the spin-dependent transport limiting the magnitude of MR effect in this first attempt at spin filter devices of CrO2 nanorods with nonmagnetic contacts.

  19. Electroluminescence and rectifying properties of heterojunction LEDs based on ZnO nanorods

    Rout, Chandra Sekhar; Rao, C N R

    2008-01-01

    n-ZnO NR/p-Si and n-ZnO NR/p-PEDOT/PSS heterojunction light-emitting diodes (LEDs) have been fabricated with ZnO nanorods (NRs) grown by a low-temperature method as well as by employing pulsed laser deposition (PLD). The low-temperature method involves growing the ZnO nanorods by the reaction of water with zinc metal. The current-voltage (I-V) characteristics of the heterojunctions show good rectifying diode characteristics. The electroluminescence (EL) spectra of the nanorods show an emission band at around 390 nm and defect related bands in the 400-550 nm region. Room-temperature electroluminescence is detected under forward bias for both the heterostructures. With the low-temperature grown nanorods, the defect related bands in the 400-550 nm range are more intense in the EL spectra, whereas with the PLD grown nanorods, only the 390 nm band is prominent

  20. Deterministic assembly of linear gold nanorod chains as a platform for nanoscale applications

    Rey, Antje; Billardon, Guillaume; Loertscher, Emanuel

    2013-01-01

    target substrate, thus establishing a platform for a variety of nanoscale electronic and optical applications ranging from molecular electronics to optical and plasmonic devices. As a first example, electrical measurements are performed on contacted gold nanorod chains before and after their immersion......We demonstrate a method to assemble gold nanorods highly deterministically into a chain formation by means of directed capillary assembly. This way we achieved straight chains consisting of end-to-end aligned gold nanorods assembled in one specific direction with well-controlled gaps of similar...... to 6 nm between the individual constituents. We determined the conditions for optimum quality and yield of nanorod chain assembly by investigating the influence of template dimensions and assembly temperature. In addition, we transferred the gold nanorod chains from the assembly template onto a Si/SiO2...

<