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Sample records for high efficiency organic

  1. High-efficiency organic glass scintillators

    Science.gov (United States)

    Feng, Patrick L.; Carlson, Joseph S.

    2017-12-19

    A new family of neutron/gamma discriminating scintillators is disclosed that comprises stable organic glasses that may be melt-cast into transparent monoliths. These materials have been shown to provide light yields greater than solution-grown trans-stilbene crystals and efficient PSD capabilities when combined with 0.01 to 0.05% by weight of the total composition of a wavelength-shifting fluorophore. Photoluminescence measurements reveal fluorescence quantum yields that are 2 to 5 times greater than conventional plastic or liquid scintillator matrices, which accounts for the superior light yield of these glasses. The unique combination of high scintillation light-yields, efficient neutron/gamma PSD, and straightforward scale-up via melt-casting distinguishes the developed organic glasses from existing scintillators.

  2. High efficient white organic light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, Stefan; Krause, Ralf [Department of Materials Science VI, University of Erlangen-Nuremberg (Germany); Siemens AG, CT MM 1, Erlangen (Germany); Kozlowski, Fryderyk; Schmid, Guenter; Hunze, Arvid [Siemens AG, CT MM 1, Erlangen (Germany); Winnacker, Albrecht [Department of Materials Science VI, University of Erlangen-Nuremberg (Germany)

    2007-07-01

    Due to the rapid progress in the last years the performance of organic light emitting diodes (OLEDs) has reached a level where general lighting presents a most interesting application target. We demonstrate, how the color coordinates of the emission spectrum can be adjusted using a combinatorial evaporation tool to lie on the desired black body curve representing cold and warm white, respectively. The evaluation includes phosphorescent and fluorescent dye approaches to optimize lifetime and efficiency, simultaneously. Detailed results are presented with respect to variation of layer thicknesses and dopant concentrations of each layer within the OLED stack. The most promising approach contains phosphorescent red and green dyes combined with a fluorescent blue one as blue phosphorescent dopants are not yet stable enough to achieve long lifetimes.

  3. High efficiency electrophosphorescence from bilayer organic light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Li Minghang; Lin, Ming-Te; Shepherd, Nigel D [Department of Material Science and Engineering, University of North Texas, Denton, TX (United States); Chen, Wei-Hsuan; Oswald, Iain; Omary, Mohammad [Department of Chemeistry, University of North Texas, Denton, TX (United States)

    2011-09-14

    An electron mobility of 2.7 x 10{sup -5} cm{sup 2} V{sup -1} s{sup -1} was measured for the phosphorescent emitter bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II)(Pt(ptp)2), which prompted its evaluation as both the emissive layer and electron transport layer in organic light emitting diodes with a simple bilayer structure. Power and external quantum efficiencies of 54.0 {+-} 0.2 lm W{sup -1} and 15.9% were obtained, which as far as we could ascertain are amongst the highest reported values for bilayer devices. We ascribe the high device efficiency to the combination of the high electron mobility, short excited-state lifetime (117 ns) and high luminescence quantum yield (60%) of the bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II). The colour temperature of the devices was 2855 K at 5 V, which places the emission in the 'warm' light spectral region.

  4. Highly efficient catalytic reductive degradation of various organic ...

    Indian Academy of Sciences (India)

    aDepartment of Applied Sciences (Chemical Science Division), GUIST, Gauhati University, ... Highly improved catalytic reductive degradation of different organic dyes, in the ... was prepared by a facile co-precipitation method using ultra-high dilute aqueous solutions. ...... face chemical-modification for engineering the intrin-.

  5. High-Efficiency BODIPY-Based Organic Photovoltaics

    KAUST Repository

    Chen, John J.; Conron, Sarah M.; Erwin, Patrick; Dimitriou, Michael; McAlahney, Kyle; Thompson, Mark E.

    2015-01-01

    © 2014 American Chemical Society. A benzannulated boron dipyrromethene (BODIPY, bDIP) molecule exhibiting strong absorption at 640 nm was synthesized. The organic dye was used in an organic solar cell as the electron donor with C60 as the acceptor. The BODIPY dye demonstrated the best performance in lamellar architecture (indium tin oxide (ITO)/bDIP/C60/bathocuproine/Al), giving power conversion efficiency up to 4.5% with short-circuit current (JSC) of 8.7 mA/cm2 and an open-circuit voltage (VOC) of 0.81 V. Neutron reflectivity experiments were performed on the bilayer film to investigate the thickness dependence of JSC. A 13 nm mixed layer was found to be present at the donor/acceptor interface in the bilayer device, formed when the C60 was deposited onto a room temperature bDIP film. Planar-mixed heterojunction devices were fabricated to understand the extent of spontaneous mixing between the donor and acceptor materials. The native mixed region in the bilayer device was shown to most resemble 1:3 bDIP:C60 layer in the structure: (ITO/bDIP/bDIP:C60 blend/C60/bathocuproine/Al).

  6. High-Efficiency BODIPY-Based Organic Photovoltaics

    KAUST Repository

    Chen, John J.

    2015-01-14

    © 2014 American Chemical Society. A benzannulated boron dipyrromethene (BODIPY, bDIP) molecule exhibiting strong absorption at 640 nm was synthesized. The organic dye was used in an organic solar cell as the electron donor with C60 as the acceptor. The BODIPY dye demonstrated the best performance in lamellar architecture (indium tin oxide (ITO)/bDIP/C60/bathocuproine/Al), giving power conversion efficiency up to 4.5% with short-circuit current (JSC) of 8.7 mA/cm2 and an open-circuit voltage (VOC) of 0.81 V. Neutron reflectivity experiments were performed on the bilayer film to investigate the thickness dependence of JSC. A 13 nm mixed layer was found to be present at the donor/acceptor interface in the bilayer device, formed when the C60 was deposited onto a room temperature bDIP film. Planar-mixed heterojunction devices were fabricated to understand the extent of spontaneous mixing between the donor and acceptor materials. The native mixed region in the bilayer device was shown to most resemble 1:3 bDIP:C60 layer in the structure: (ITO/bDIP/bDIP:C60 blend/C60/bathocuproine/Al).

  7. High mobility high efficiency organic films based on pure organic materials

    Science.gov (United States)

    Salzman, Rhonda F [Ann Arbor, MI; Forrest, Stephen R [Ann Arbor, MI

    2009-01-27

    A method of purifying small molecule organic material, performed as a series of operations beginning with a first sample of the organic small molecule material. The first step is to purify the organic small molecule material by thermal gradient sublimation. The second step is to test the purity of at least one sample from the purified organic small molecule material by spectroscopy. The third step is to repeat the first through third steps on the purified small molecule material if the spectroscopic testing reveals any peaks exceeding a threshold percentage of a magnitude of a characteristic peak of a target organic small molecule. The steps are performed at least twice. The threshold percentage is at most 10%. Preferably the threshold percentage is 5% and more preferably 2%. The threshold percentage may be selected based on the spectra of past samples that achieved target performance characteristics in finished devices.

  8. Exciplex-Forming Cohost for High Efficiency and High Stability Phosphorescent Organic Light-Emitting Diodes.

    Science.gov (United States)

    Shih, Chun-Jen; Lee, Chih-Chien; Chen, Ying-Hao; Biring, Sajal; Kumar, Gautham; Yeh, Tzu-Hung; Sen, Somaditya; Liu, Shun-Wei; Wong, Ken-Tsung

    2018-01-17

    An exciplex forming cohost system is employed to achieve a highly efficient organic light-emitting diode (OLED) with good electroluminescent lifetime. The exciplex is formed at the interfacial contact of a conventional star-shaped carbazole hole-transporting material, 4,4',4″-tris(N-carbazolyl)-triphenylamine (TCTA), and a triazine electron-transporting material, 2,4,6-tris[3-(1H-pyrazol-1-yl)phenyl]-1,3,5-triazine (3P-T2T). The excellent combination of TCTA and 3P-T2T is applied as the cohost of a common green phosphorescent emitter with almost zero energy loss. When Ir(ppy) 2 (acac) is dispersed in such exciplex cohost system, OLED device with maximum external quantum efficiency of 29.6%, the ultrahigh power efficiency of 147.3 lm/W, and current efficiency of 107 cd/A were successfully achieved. More importantly, the OLED device showed a low-efficiency roll-off and an operational lifetime (τ 80 ) of ∼1020 min with the initial brightness of 2000 cd/m 2 , which is 56 times longer than the reference device. The significant difference of device stability was attributed to the degradation of exciplex system for energy transfer process, which was investigated by the photoluminescence aging measurement at room temperature and 100 K, respectively.

  9. Highly efficient exciplex organic light-emitting diodes incorporating a heptazine derivative as an electron acceptor.

    Science.gov (United States)

    Li, Jie; Nomura, Hiroko; Miyazaki, Hiroshi; Adachi, Chihaya

    2014-06-11

    Highly efficient exciplex systems incorporating a heptazine derivative () as an electron acceptor and 1,3-di(9H-carbazol-9-yl)benzene () as an electron donor are developed. An organic light-emitting diode containing 8 wt% : as an emitting layer exhibits a maximum external quantum efficiency of 11.3%.

  10. Very high efficiency phosphorescent organic light-emitting devices by using rough indium tin oxide

    International Nuclear Information System (INIS)

    Zhang, Yingjie; Aziz, Hany

    2014-01-01

    The efficiency of organic light-emitting devices (OLEDs) is shown to significantly depend on the roughness of the indium tin oxide (ITO) anode. By using rougher ITO, light trapped in the ITO/organic wave-guided mode can be efficiently extracted, and a light outcoupling enhancement as high as 40% is achieved. Moreover, contrary to expectations, the lifetime of OLEDs is not affected by ITO roughness. Finally, an OLED employing rough ITO anode that exhibits a current efficiency of 56 cd/A at the remarkably high brightness of 10 5  cd/m 2 is obtained. This represents the highest current efficiency at such high brightness to date for an OLED utilizing an ITO anode, without any external light outcoupling techniques. The results demonstrate the significant efficiency benefits of using ITO with higher roughness in OLEDs.

  11. Very high efficiency phosphorescent organic light-emitting devices by using rough indium tin oxide

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingjie; Aziz, Hany, E-mail: h2aziz@uwaterloo.ca [Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada)

    2014-07-07

    The efficiency of organic light-emitting devices (OLEDs) is shown to significantly depend on the roughness of the indium tin oxide (ITO) anode. By using rougher ITO, light trapped in the ITO/organic wave-guided mode can be efficiently extracted, and a light outcoupling enhancement as high as 40% is achieved. Moreover, contrary to expectations, the lifetime of OLEDs is not affected by ITO roughness. Finally, an OLED employing rough ITO anode that exhibits a current efficiency of 56 cd/A at the remarkably high brightness of 10{sup 5} cd/m{sup 2} is obtained. This represents the highest current efficiency at such high brightness to date for an OLED utilizing an ITO anode, without any external light outcoupling techniques. The results demonstrate the significant efficiency benefits of using ITO with higher roughness in OLEDs.

  12. Highly efficient deep-blue organic light emitting diode with a carbazole based fluorescent emitter

    Science.gov (United States)

    Sahoo, Snehasis; Dubey, Deepak Kumar; Singh, Meenu; Joseph, Vellaichamy; Thomas, K. R. Justin; Jou, Jwo-Huei

    2018-04-01

    High efficiency deep-blue emission is essential to realize energy-saving, high-quality display and lighting applications. We demonstrate here a deep-blue organic light emitting diode using a novel carbazole based fluorescent emitter 7-[4-(diphenylamino)phenyl]-9-(2-ethylhexyl)-9H-carbazole-2-carbonitrile (JV234). The solution processed resultant device shows a maximum luminance above 1,750 cd m-2 and CIE coordinates (0.15,0.06) with a 1.3 lm W-1 power efficiency, 2.0 cd A-1 current efficiency, and 4.1% external quantum efficiency at 100 cd m-2. The resulting deep-blue emission enables a greater than 100% color saturation. The high efficiency may be attributed to the effective host-to-guest energy transfer, suitable device architecture facilitating balanced carrier injection and low doping concentration preventing efficiency roll-off caused by concentration quenching.

  13. High-efficiency white organic light-emitting diodes using thermally activated delayed fluorescence

    International Nuclear Information System (INIS)

    Nishide, Jun-ichi; Hiraga, Yasuhide; Nakanotani, Hajime; Adachi, Chihaya

    2014-01-01

    White organic light-emitting diodes (WOLEDs) have attracted much attention recently, aimed for next-generation lighting sources because of their high potential to realize high electroluminescence efficiency, flexibility, and low-cost manufacture. Here, we demonstrate high-efficiency WOLED using red, green, and blue thermally activated delayed fluorescence materials as emissive dopants to generate white electroluminescence. The WOLED has a maximum external quantum efficiency of over 17% with Commission Internationale de l'Eclairage coordinates of (0.30, 0.38).

  14. Environmentally Printing Efficient Organic Tandem Solar Cells with High Fill Factors: A Guideline Towards 20% Power Conversion Efficiency

    DEFF Research Database (Denmark)

    Li, Ning; Baran, Derya; Spyropoulos, George D.

    2014-01-01

    presents a major challenge. The reported high PCE values from lab-scale spin-coated devices are, of course, representative, but not helpful for commercialization. Here, organic tandem solar cells with exceptionally high fill factors and PCE values of 7.66% (on glass) and 5.56% (on flexible substrate...... to enhance the power conversion efficiency (PCE). However, due to the undeveloped deposition techniques, the challenges in ink formulation as well as the lack of commercially available high performance active materials, roll-to-roll fabrication of highly efficient organic tandem solar cells currently......), which are the highest values for the solution-processed tandem solar cells fabricated by a mass-production compatible coating technique under ambient conditions, are demonstrated. To predict the highest possible performance of tandem solar cells, optical simulation based on experimentally feasible...

  15. Highly efficient greenish-blue platinum-based phosphorescent organic light-emitting diodes on a high triplet energy platform

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Y. L., E-mail: yilu.chang@mail.utoronto.ca; Gong, S., E-mail: sgong@chem.utoronto.ca; White, R.; Lu, Z. H., E-mail: zhenghong.lu@utoronto.ca [Department of Materials Science and Engineering, University of Toronto, 184 College St., Toronto, Ontario M5S 3E4 (Canada); Wang, X.; Wang, S., E-mail: wangs@chem.queensu.ca [Department of Chemistry, Queen' s University, 90 Bader Lane, Kingston, Ontario K7L 3N6 (Canada); Yang, C. [Department of Chemistry, Wuhan University, Wuhan 430072 (China)

    2014-04-28

    We have demonstrated high-efficiency greenish-blue phosphorescent organic light-emitting diodes (PHOLEDs) based on a dimesitylboryl-functionalized C^N chelate Pt(II) phosphor, Pt(m-Bptrz)(t-Bu-pytrz-Me). Using a high triplet energy platform and optimized double emissive zone device architecture results in greenish-blue PHOLEDs that exhibit an external quantum efficiency of 24.0% and a power efficiency of 55.8 lm/W. This record high performance is comparable with that of the state-of-the-art Ir-based sky-blue organic light-emitting diodes.

  16. Organic dye for highly efficient solid-state dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt-Mende, L.; Bach, U.; Humphry-Baker, R.; Ito, S.; Graetzel, M. [Institut des Sciences et Ingenierie Chimiques (ISIC), Laboratoire de Photonique et Interfaces (LPI), Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Horiuchi, T.; Miura, H. [Technology Research Laboratory, Corporate Research Center, Mitsubishi Paper Mills Limited, 46, Wadai, Tsukuba City, Ibaraki 300-4247 (Japan); Uchida, S. [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1-1 Katahira 2-chome, Aoba-ku, Sendai 980-8577 (Japan)

    2005-04-04

    The feasibility of solid-state dye-sensitized solar cells as a low-cost alternative to amorphous silicon cells is demonstrated. Such a cell with a record efficiency of over 4 % under simulated sunlight is reported, made possible by using a new organic metal-free indoline dye as the sensitizer with high absorption coefficient. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  17. In silico evaluation of highly efficient organic light-emitting materials

    Science.gov (United States)

    Kwak, H. Shaun; Giesen, David J.; Hughes, Thomas F.; Goldberg, Alexander; Cao, Yixiang; Gavartin, Jacob; Dixon, Steve; Halls, Mathew D.

    2016-09-01

    Design and development of highly efficient organic and organometallic dopants is one of the central challenges in the organic light-emitting diodes (OLEDs) technology. Recent advances in the computational materials science have made it possible to apply computer-aided evaluation and screening framework directly to the design space of organic lightemitting diodes (OLEDs). In this work, we will showcase two major components of the latest in silico framework for development of organometallic phosphorescent dopants - (1) rapid screening of dopants by machine-learned quantum mechanical models and (2) phosphorescence lifetime predictions with spin-orbit coupled calculations (SOC-TDDFT). The combined work of virtual screening and evaluation would significantly widen the design space for highly efficient phosphorescent dopants with unbiased measures to evaluate performance of the materials from first principles.

  18. High-efficiency THz modulator based on phthalocyanine-compound organic films

    International Nuclear Information System (INIS)

    He, Ting; Zhang, Bo; Shen, Jingling; Zang, Mengdi; Chen, Tianji; Hu, Yufeng; Hou, Yanbing

    2015-01-01

    We report a high efficiency, broadband terahertz (THz) modulator following a study of phthalocyanine-compound organic films irradiated with an external excitation laser. Both transmission and reflection modulations of each organic/silicon bilayers were measured using THz time-domain and continuous-wave systems. For very low intensities, the experimental results show that AlClPc/Si can achieve a high modulation factor for transmission and reflection, indicating that AlClPc/Si has a superior modulation efficiency compared with the other films (CuPc and SnCl 2 Pc). In contrast, the strong attenuation of the transmitted and reflected THz waves revealed that a nonlinear absorption process takes place at the organic/silicon interface

  19. Highly efficient tandem organic light-emitting devices employing an easily fabricated charge generation unit

    Science.gov (United States)

    Yang, Huishan; Yu, Yaoyao; Wu, Lishuang; Qu, Biao; Lin, Wenyan; Yu, Ye; Wu, Zhijun; Xie, Wenfa

    2018-02-01

    We have realized highly efficient tandem organic light-emitting devices (OLEDs) employing an easily fabricated charge generation unit (CGU) combining 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile with ultrathin bilayers of CsN3 and Al. The charge generation and separation processes of the CGU have been demonstrated by studying the differences in the current density-voltage characteristics of external-carrier-excluding devices. At high luminances of 1000 and 10000 cd/m2, the current efficiencies of the phosphorescent tandem device are about 2.2- and 2.3-fold those of the corresponding single-unit device, respectively. Simultaneously, an efficient tandem white OLED exhibiting high color stability and warm white emission has also been fabricated.

  20. Modulate Organic-Metal Oxide Heterojunction via [1,6] Azafulleroid for Highly Efficient Organic Solar Cells.

    Science.gov (United States)

    Li, Chang-Zhi; Huang, Jiang; Ju, Huanxin; Zang, Yue; Zhang, Jianyuan; Zhu, Junfa; Chen, Hongzheng; Jen, Alex K-Y

    2016-09-01

    By creating an effective π-orbital hybridization between the fullerene cage and the aromatic anchor (addend), the azafulleroid interfacial modifiers exhibit enhanced electronic coupling to the underneath metal oxides. High power conversion efficiency of 10.3% can be achieved in organic solar cells using open-cage phenyl C61 butyric acid methyl ester (PCBM)-modified zinc oxide layer. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Progress in high-efficient solution process organic photovoltaic devices fundamentals, materials, devices and fabrication

    CERN Document Server

    Li, Gang

    2015-01-01

    This book presents an important technique to process organic photovoltaic devices. The basics, materials aspects and manufacturing of photovoltaic devices with solution processing are explained. Solution processable organic solar cells - polymer or solution processable small molecules - have the potential to significantly reduce the costs for solar electricity and energy payback time due to the low material costs for the cells, low cost and fast fabrication processes (ambient, roll-to-roll), high material utilization etc. In addition, organic photovoltaics (OPV) also provides attractive properties like flexibility, colorful displays and transparency which could open new market opportunities. The material and device innovations lead to improved efficiency by 8% for organic photovoltaic solar cells, compared to 4% in 2005. Both academic and industry research have significant interest in the development of this technology. This book gives an overview of the booming technology, focusing on the solution process fo...

  2. High-Efficiency Silicon/Organic Heterojunction Solar Cells with Improved Junction Quality and Interface Passivation.

    Science.gov (United States)

    He, Jian; Gao, Pingqi; Ling, Zhaoheng; Ding, Li; Yang, Zhenhai; Ye, Jichun; Cui, Yi

    2016-12-27

    Silicon/organic heterojunction solar cells (HSCs) based on conjugated polymers, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), and n-type silicon (n-Si) have attracted wide attention due to their potential advantages of high efficiency and low cost. However, the state-of-the-art efficiencies are still far from satisfactory due to the inferior junction quality. Here, facile treatments were applied by pretreating the n-Si wafer in tetramethylammonium hydroxide (TMAH) solution and using a capping copper iodide (CuI) layer on the PEDOT:PSS layer to achieve a high-quality Schottky junction. Detailed photoelectric characteristics indicated that the surface recombination was greatly suppressed after TMAH pretreatment, which increased the thickness of the interfacial oxide layer. Furthermore, the CuI capping layer induced a strong inversion layer near the n-Si surface, resulting in an excellent field effect passivation. With the collaborative improvements in the interface chemical and electrical passivation, a competitive open-circuit voltage of 0.656 V and a high fill factor of 78.1% were achieved, leading to a stable efficiency of over 14.3% for the planar n-Si/PEDOT:PSS HSCs. Our findings suggest promising strategies to further exploit the full voltage as well as efficiency potentials for Si/organic solar cells.

  3. Highly efficient white top-emitting organic light-emitting diodes with forward directed light emission

    Energy Technology Data Exchange (ETDEWEB)

    Freitag, Patricia; Reineke, Sebastian; Furno, Mauro; Luessem, Bjoern; Leo, Karl [Institut fuer Angewandte Photophysik, TU Dresden (Germany)

    2010-07-01

    The demand for highly efficient and energy saving illumination has increased considerably during the last decades. Organic light emitting diodes (OLEDs) are promising candidates for future lighting technologies. They offer high efficiency along with excellent color quality, allowing substantially lower power consumption than traditional illuminants. Recently, especially top-emitting devices have attracted high interest due to their compatibility with opaque substrates like metal sheets. In this contribution, we demonstrate top-emitting OLEDs with white emission spectra employing a multilayer hybrid cavity structure with two highly efficient phosphorescent emitter materials for orange-red (Ir(MDQ)2(acac)) and green (Ir(ppy)3) emission as well as the stable fluorescent blue emitter TBPe. To improve the OLED performance and modify the color quality, two different electron blocking layers and anode material combinations are tested. Compared to Lambertian emission, our devices show considerably enhanced forward emission, which is preferred for most lighting applications. Besides broadband emission and angle independent emission maxima, power efficiencies of 13.3 lm/W at 3 V and external quantum efficiencies of 5.3% are achieved. The emission shows excellent CIE coordinates of (0.420,0.407) at approx. 1000 cd/m{sup 2} and color rendering indices up to 77.

  4. Highly efficient phosphorescent blue and white organic light-emitting devices with simplified architectures

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chih-Hao, E-mail: chc@saturn.yzu.edu.tw [Department of Photonics Engineering, Yuan Ze University, Chung-Li, Taiwan 32003 (China); Ding, Yong-Shung; Hsieh, Po-Wei; Chang, Chien-Ping; Lin, Wei-Chieh [Department of Photonics Engineering, Yuan Ze University, Chung-Li, Taiwan 32003 (China); Chang, Hsin-Hua, E-mail: hhua3@mail.vnu.edu.tw [Department of Electro-Optical Engineering, Vanung University, Chung-Li, Taiwan 32061 (China)

    2011-09-01

    Blue phosphorescent organic light-emitting devices (PhOLEDs) with quantum efficiency close to the theoretical maximum were achieved by utilizing a double-layer architecture. Two wide-triplet-gap materials, 1,3-bis(9-carbazolyl)benzene and 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, were employed in the emitting and electron-transport layers respectively. The opposite carrier-transport characteristics of these two materials were leveraged to define the exciton formation zone and thus increase the probability of recombination. The efficiency at practical luminance (100 cd/m{sup 2}) was as high as 20.8%, 47.7 cd/A and 31.2 lm/W, respectively. Furthermore, based on the design concept of this simplified architecture, efficient warmish-white PhOLEDs were developed. Such two-component white organic light-emitting devices exhibited rather stable colors over a wide brightness range and yielded electroluminescence efficiencies of 15.3%, 33.3 cd/A, and 22.7 lm/W in the forward directions.

  5. Highly efficient phosphorescent blue and white organic light-emitting devices with simplified architectures

    International Nuclear Information System (INIS)

    Chang, Chih-Hao; Ding, Yong-Shung; Hsieh, Po-Wei; Chang, Chien-Ping; Lin, Wei-Chieh; Chang, Hsin-Hua

    2011-01-01

    Blue phosphorescent organic light-emitting devices (PhOLEDs) with quantum efficiency close to the theoretical maximum were achieved by utilizing a double-layer architecture. Two wide-triplet-gap materials, 1,3-bis(9-carbazolyl)benzene and 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, were employed in the emitting and electron-transport layers respectively. The opposite carrier-transport characteristics of these two materials were leveraged to define the exciton formation zone and thus increase the probability of recombination. The efficiency at practical luminance (100 cd/m 2 ) was as high as 20.8%, 47.7 cd/A and 31.2 lm/W, respectively. Furthermore, based on the design concept of this simplified architecture, efficient warmish-white PhOLEDs were developed. Such two-component white organic light-emitting devices exhibited rather stable colors over a wide brightness range and yielded electroluminescence efficiencies of 15.3%, 33.3 cd/A, and 22.7 lm/W in the forward directions.

  6. Prediction and design of efficient exciplex emitters for high-efficiency, thermally activated delayed-fluorescence organic light-emitting diodes.

    Science.gov (United States)

    Liu, Xiao-Ke; Chen, Zhan; Zheng, Cai-Jun; Liu, Chuan-Lin; Lee, Chun-Sing; Li, Fan; Ou, Xue-Mei; Zhang, Xiao-Hong

    2015-04-08

    High-efficiency, thermally activated delayed-fluorescence organic light-emitting diodes based on exciplex emitters are demonstrated. The best device, based on a TAPC:DPTPCz emitter, shows a high external quantum efficiency of 15.4%. Strategies for predicting and designing efficient exciplex emitters are also provided. This approach allow prediction and design of efficient exciplex emitters for achieving high-efficiency organic light-emitting diodes, for future use in displays and lighting applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. A highly energy-efficient flow-through electro-Fenton process for organic pollutants degradation

    International Nuclear Information System (INIS)

    Ma, Liang; Zhou, Minghua; Ren, Gengbo; Yang, Weilu; Liang, Liang

    2016-01-01

    Highlights: • A highly energy-efficient flow-through electro-Fenton reactor was designed. • It had high H 2 O 2 yield and low energy consumption for organic pollutants degradation. • The effect of operational parameters was optimized and possible process mechanism was studied. • The novel system performed wide practicability and potential for organic pollutants degradation. - Abstract: A highly energy-efficient flow-through Electro-Fenton (E-Fenton) reactor for oxidation of methylene blue (MB) from aqueous solution was designed using a perforated DSA as anode and the graphite felt modified by carbon black and polytetrafluoroethylene (PTFE) as cathode for the in situ generation of H 2 O 2 . The modified cathode had a high H 2 O 2 production with low energy consumption, which was characterized by scanning electron microscopy (SEM), nitrogen adsorption-desorption study and contact angle. The flow-through E-Fenton system was compared to the flow-by and regular one, and confirmed to be best on MB removal and TOC degradation. The operational parameters such as current density, pH, Fe 2+ concentration and flow rate were optimized. The MB and TOC removal efficiency of the effluents could keep above 90% and 50%, respectively, and the energy consumption was 23.0 kWh/kgTOC at the current density of 50 mA, pH 3, 0.3 mM Fe 2+ , and the flow rate of 7 mL/min. ·OH was proved to be the main oxidizing species in this system. After 5 times operation, the system, especially cathode, still showed good stability. Five more organic pollutants including orange II (OG), tartrazine, acetylsalicylic acid (ASA), tetracycline (TC) and 2,4-dichlorophen (2,4-DCP) were investigated and the electric energy consumption (EEC) was compared with literatures. All results demonstrated that this flow-through E-Fenton system was energy-efficient and potential for degradation of organic pollutants.

  8. High-efficiency technology for lithium isotope separation using an ionic-liquid impregnated organic membrane

    International Nuclear Information System (INIS)

    Hoshino, Tsuyoshi; Terai, Takayuki

    2011-01-01

    The tritium needed as a fuel for fusion reactors is produced by the neutron capture reaction of lithium-6 ( 6 Li) in tritium breeding materials. New lithium isotope separation technique using ionic-liquid impregnated organic membranes (Ionic-Liquid-i-OMs) have been developed. Lithium ions are able to move by electrodialysis through certain Ionic-Liquid-i-OMs between the cathode and the anode in lithium solutions. In this report, the effects of protection cover and membrane thickness on the durability of membrane and the efficiency of isotope separation were evaluated. In order to improve the durability of the Ionic-Liquid-i-OM, we developed highly-durable Ionic-Liquid-i-OM. Both surfaces of the Ionic-Liquid-i-OM were covered by a nafion 324 overcoat or a cation exchange membrane (SELEMION TM CMD) to prevent the outflow of the ionic liquid. It was observed that the durability of the Ionic-Liquid-i-OM was improved by a nafion 324 overcoat. On the other hand, the organic membrane selected was 1, 2 or 3 mm highly-porous Teflon film, in order to efficiently impregnate the ionic liquid. The 6 Li isotope separation factor by electrodialysis using highly-porous Teflon film of 3 mm thickness was larger than using that of 1 or 2 mm thickness.

  9. Organic Removal Efficiency of the Nanofiltration and Adsorption Hybrid System in High Strength Wastewater

    Directory of Open Access Journals (Sweden)

    Amir Hessam Hassani

    2011-03-01

    Full Text Available Surface and groundwater resources are increasingly jeopardized by discharges from pharmaceutical, chemical, and detergent plants. The high pollutant load of the effluents from these industries requires specific treatments. The objective of this research was to study and compare the nanofiltration and adsorption hybrid system with the plain nanofiltration system in wastewater treatment.For this purpose, a pilot nanofiltration system with a capacity of 7.6 m3/d using 1 and 5 micron filters and a FILMTEC NF90-4040 membrane was used in the first phase of the study. In the second phase, granular activated carbon cartridges were used. Inluent and effluent discharges as well as the COD removal were measured in both systems under variable times and organic load conditions. The results showed that COD removal efficiency was higher in the hybrid system than in the plain naonofiltration one. In the hybrid system, the Maximum in the hybrid system, the COD removal efficiencies achieved for organic loads of 1000, 2000, and 3000 mg/L were 99%, 95.86%, and 92.93%, respectively. The same values for the plain nanofiltration system were 87.34%, 50%, and 29.41%, respectively. It was found that polarization and membrane fouling decreased both the effluent flow and the COD removal efficiency with time. Fouling of the membrane was, however, lower in the hybrid system compared to the plain nanofiltration; thus, the hybrid system was associated with higher values of COD removal and delayed membrane fouling.

  10. Highly efficient white organic light-emitting devices consisting of undoped ultrathin yellow phosphorescent layer

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shengqiang [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Ma, Zhu; Zhao, Juan [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

    2013-02-15

    High-efficiency white organic light-emitting devices (WOLEDs) based on an undoped ultrathin yellow light-emitting layer and a doped blue light-emitting layer were demonstrated. While the thickness of blue light-emitting layer, formed by doping a charge-trapping phosphor, iridium(III) bis(4 Prime ,6 Prime -difluorophenylpyridinato)tetrakis(1-pyrazolyl)borate (FIr6) in a wide bandgap host, was kept constant, the thickness of neat yellow emissive layer of novel phosphorescent material, bis[2-(4-tertbutylphenyl)benzothiazolato-N,C{sup 2 Prime }]iridium (acetylacetonate) [(t-bt){sub 2}Ir(acac)] was varied to optimize the device performance. The optimized device exhibited maximum luminance, current efficiency and power efficiency of 24,000 cd/m{sup 2} (at 15.2 V), 79.0 cd/A (at 1550 cd/m{sup 2}) and 40.5 lm/W (at 1000 cd/m{sup 2}), respectively. Besides, the white-light emission covered a wide range of visible spectrum, and the Commission Internationale de l'Eclairage coordinates were (0.32, 0.38) with a color temperature of 5800 K at 8 V. Moreover, high external quantum efficiency was also obtained in the high-efficiency WOLEDs. The performance enhancement was attributed to the proper thickness of (t-bt){sub 2}Ir(acac) layer that enabled adequate current density and enough phosphorescent dye to trap electrons. - Highlights: Black-Right-Pointing-Pointer Highly efficient WOLEDs based on two complementary layers were fabricated. Black-Right-Pointing-Pointer The yellow emissive layer was formed by utilizing undoping system. Black-Right-Pointing-Pointer The blue emissive layer was made by host-guest doping system. Black-Right-Pointing-Pointer The thickness of the yellow emissive layer was varied to make device optimization. Black-Right-Pointing-Pointer The optimized device achieved high power efficiency of 40.5 lm/W.

  11. Organic MEMS/NEMS-based high-efficiency 3D ITO-less flexible photovoltaic cells

    International Nuclear Information System (INIS)

    Kassegne, Sam; Moon, Kee; Martín-Ramos, Pablo; Majzoub, Mohammad; Őzturk, Gunay; Desai, Krishna; Parikh, Mihir; Nguyen, Bao; Khosla, Ajit; Chamorro-Posada, Pedro

    2012-01-01

    A novel approach based on three-dimensional (3D) architecture for polymeric photovoltaic cells made up of an array of sub-micron and nano-pillars which not only increase the area of the light absorbing surface, but also improve the carrier collection efficiency of bulk-heterojunction organic solar cells is presented. The approach also introduces coating of 3D anodes with a new solution-processable highly conductive transparent polymer (Orgacon™) that replaces expensive vacuum-deposited ITO (indium tin oxide) as well as the additional hole-collecting layer of conventional PEDOT:PSS (poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)). In addition, the described procedure is well suited to roll-to-roll high-throughput manufacturing. The high aspect-ratio 3D pillars which form the basis for this new architecture are patterned through micro-electromechanical-system- and nano-electromechanical-system-based processes. For the particular case of P3HT (poly(3-hexylthiophene)) and PCBM (phenyl-C61-butyric acid methyl ester) active material, efficiencies in excess of 6% have been achieved for these photovoltaic cells of 3D architecture using ITO-less flexible PET (polyethylene terephthalate) substrates. This increase in efficiency turns out to be more than twice higher than those achieved for their 2D counterparts. (paper)

  12. High-Efficiency Small-Scale Combined Heat and Power Organic Binary Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Costante Mario Invernizzi

    2018-04-01

    Full Text Available Small-CHP (Combined Heat and Power systems are generally considered a valuable technological option to the conventional boilers, in a technology developed context. If small-CHP systems are associated with the use of renewable energies (biomass, for example they could play an important role in distributed generation even in developing countries or, in any case, where there are no extensive electricity networks. Traditionally the considered heat engines for micro- or mini-CHP are: the gas engine, the gas turbine (with internal combustion, the steam engine, engine working according to the Stirling and to the Rankine cycles, the last with organic fluids. In principle, also fuel cells could be used. In this paper, we focus on small size Rankine cycles (10–15 k W with organic working fluids. The assumed heat source is hot combustion gases at high temperature (900–950 ∘ C and we assume to use only single stages axial turbines. The need to work at high temperatures, limits the choice of the right organic working fluids. The calculation results show the limitation in the performances of simple cycles and suggest the opportunity to resort to complex (binary cycle configurations to achieve high net conversion efficiencies (15–16%.

  13. Highly efficient red phosphorescent organic light-emitting diodes based on solution processed emissive layer

    International Nuclear Information System (INIS)

    Liu, Baiquan; Xu, Miao; Tao, Hong; Ying, Lei; Zou, Jianhua; Wu, Hongbin; Peng, Junbiao

    2013-01-01

    Highly efficient red phosphorescent organic polymer light-emitting diodes (PhOLEDs) were fabricated based on a solution-processed small-molecule host 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) by doping an iridium complex, tris(1-(2,6-dimethylphenoxy)-4-(4-chlorophenyl)phthalazine)iridium (III) (Ir(MPCPPZ) 3 ). A hole blocking layer 1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl (TPBI) with a function of electron transport was thermally deposited onto the top of CBP layer. The diode with the structure of ITO/PEDOT:PSS (50 nm)/CBP:Ir(MPCPPZ) 3 (55 nm)/TPBI (30 nm)/Ba (4 nm)/Al (120 nm) showed an external quantum efficiency (QE ext ) of 19.3% and luminous efficiency (LE) of 18.3 cd/A at a current density of 0.16 mA/cm 2 , and Commission International de I'Eclairage (CIE) coordinates of (0.607, 0.375). It was suggested that the diodes using TPBI layer exhibited nearly 100% internal quantum efficiency and one order magnitude enhanced LE or QE ext efficiencies. -- Highlights: • Efficient red PhOLEDs based on a solution-processed small-molecule host were fabricated. • By altering volume ratio of chloroform/chlorobenzene solvent, we got best film quality of CBP. • EQE of the diode was 19.3%, indicating nearly 100% internal quantum yield was achieved

  14. Novel Low Cost Organic Vapor Jet Printing of Striped High Efficiency Phosphorescent OLEDs for White Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Mike Hack

    2008-12-31

    In this program, Universal Display Corporation and University of Michigan proposed to integrate three innovative concepts to meet the DOE's Solid State Lighting (SSL) goals: (1) high-efficiency phosphorescent organic light emitting device (PHOLED{trademark}) technology, (2) a white lighting design that is based on a series of red, green and blue OLED stripes, and (3) the use of a novel cost-effective, high rate, mask-less deposition process called organic vapor jet printing (OVJP). Our PHOLED technology offers up to four-times higher power efficiency than other OLED approaches for general lighting. We believe that one of the most promising approaches to maximizing the efficiency of OLED lighting sources is to produce stripes of the three primary colors at such a pitch (200-500 {mu}m) that they appear as a uniform white light to an observer greater than 1 meter (m) away from the illumination source. Earlier work from a SBIR Phase 1 entitled 'White Illumination Sources Using Striped Phosphorescent OLEDs' suggests that stripe widths of less than 500 {mu}m appear uniform from a distance of 1m without the need for an external diffuser. In this program, we intend to combine continued advances in this PHOLED technology with the striped RGB lighting design to demonstrate a high-efficiency, white lighting source. Using this background technology, the team has focused on developing and demonstrating the novel cost-effective OVJP process to fabricate these high-efficiency white PHOLED light sources. Because this groundbreaking OVJP process is a direct printing approach that enables the OLED stripes to be printed without a shadow mask, OVJP offers very high material utilization and high throughput without the costs and wastage associated with a shadow mask (i.e. the waste of material that deposits on the shadow mask itself). As a direct printing technique, OVJP also has the potential to offer ultra-high deposition rates (> 1,000 Angstroms/second) for any size or

  15. Low-voltage and high-efficiency white organic light emitting devices with carrier balance

    International Nuclear Information System (INIS)

    Wei Fuxiang; Huang, Y.; Fang, L.

    2010-01-01

    White organic light emitting devices with the structure of ITO/m-MTDATA:x%4F-TCNQ/NPB/TBADN:EBDP:DCJTB/Bphen:Liq/LiF/Al have been demonstrated in this paper. High-mobility m-MTDATA:4F-TCNQ is added into the region between ITO and NBP to increase hole injection and transport. The high-mobility Bphen:Liq layer is added into the region between cathode and emission layers to lower cathode barrier and facilitate carrier injection. In the meanwhile, an effective carrier balance (number of holes is equal to number of electrons) between holes and electrons is considered to be one of the most important factors for improving OLEDs. During the experiment, by modulating the doping concentration of 4F-TCNQ, we can control hole injection and transport to make the carriers reach a high-level balance. The maximum current efficiency and power efficiency of devices were 9.3 cd/A and 4.6 lm/A, respectively.

  16. Highly efficient low color temperature organic LED using blend carrier modulation layer

    Science.gov (United States)

    Hsieh, Yao-Ching; Chen, Szu-Hao; Shen, Shih-Ming; Wang, Ching-Chiun; Chen, Chien-Chih; Jou, Jwo-Huei

    2012-10-01

    Color temperature (CT) of light has great effect on human physiology and psychology, and low CT light, minimizing melatonin suppression and decreasing the risk of breast, colorectal, and prostate cancer. We demonstrates the incorporation of a blend carrier modulation interlayer (CML) between emissive layers to improve the device performance of low CT organic light emitting diodes, which exhibits an external quantum efficiency of 22.7% and 36 lm W-1 (54 cd A-1) with 1880 K at 100 cd m-2, or 20.8% and 29 lm W-1 (50 cd A-1) with 1940 K at 1000 cd m-2. The result shows a CT much lower than that of incandescent bulbs, which is 2500 K with 15 lmW-1 efficiency, and even as low as that of candles, which is 2000 K with 0.1 lmW-1. The high efficiency of the proposed device may be attributed to its CML, which helps effectively distribute the entering carriers into the available recombination zones.

  17. High Efficiency Inverted Organic Solar Cells with a Neutral Fulleropyrrolidine Electron Collecting Interlayer

    KAUST Repository

    Xu, Weidong; Yan, Congfei; Kan, Zhipeng; Wang, Yang; Lai, Wen-Yong; Huang, Wei

    2016-01-01

    A novel fulleropyrrolidine derivative, named as FPNOH, was designed, synthesized and utilized as an efficient electron-collecting (EC) layer for inverted organic solar cells (i-OSCs). The grafted diethanolamino-polar moieties can not only trigger its function as an EC interlayer, but also induce orthogonal solubility that guarantees subsequent multi-layer processing without interfacial mixing. A higher power conversion efficiency (PCE) value of 8.34% was achieved for i-OSC devices with ITO/FPNOH EC electrode, compared to that of the sol-gel ZnO based reference devices with an optimized PCE value of 7.92%. High efficiency exceeding 7.7% was still achieved even for the devices with a relatively thick PFNOH film (16.9 nm). It is worthwhile to mention that this kind of material exhibits less thickness dependent performance, in contrast to widely utilized p-type conjugated polyelectrolytes (CPEs) as well as the non-conjugated polyelectrolytes (NCPEs). Further investigation on illuminating intensity dependent parameters revealed the role of FPNOH in reducing interfacial traps-induced recombination at ITO/active layer interface.

  18. High Efficiency Inverted Organic Solar Cells with a Neutral Fulleropyrrolidine Electron Collecting Interlayer

    KAUST Repository

    Xu, Weidong

    2016-05-20

    A novel fulleropyrrolidine derivative, named as FPNOH, was designed, synthesized and utilized as an efficient electron-collecting (EC) layer for inverted organic solar cells (i-OSCs). The grafted diethanolamino-polar moieties can not only trigger its function as an EC interlayer, but also induce orthogonal solubility that guarantees subsequent multi-layer processing without interfacial mixing. A higher power conversion efficiency (PCE) value of 8.34% was achieved for i-OSC devices with ITO/FPNOH EC electrode, compared to that of the sol-gel ZnO based reference devices with an optimized PCE value of 7.92%. High efficiency exceeding 7.7% was still achieved even for the devices with a relatively thick PFNOH film (16.9 nm). It is worthwhile to mention that this kind of material exhibits less thickness dependent performance, in contrast to widely utilized p-type conjugated polyelectrolytes (CPEs) as well as the non-conjugated polyelectrolytes (NCPEs). Further investigation on illuminating intensity dependent parameters revealed the role of FPNOH in reducing interfacial traps-induced recombination at ITO/active layer interface.

  19. High-efficient and brightness white organic light-emitting diodes operated at low bias voltage

    Science.gov (United States)

    Zhang, Lei; Yu, Junsheng; Yuan, Kai; Jian, Yadong

    2010-10-01

    White organic light-emitting diodes (OLEDs) used for display application and lighting need to possess high efficiency, high brightness, and low driving voltage. In this work, white OLEDs consisted of ambipolar 9,10-bis 2-naphthyl anthracene (ADN) as a host of blue light-emitting layer (EML) doped with tetrabutyleperlene (TBPe) and a thin codoped layer consisted of N, N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine (NPB) as a host of yellow light-emitting layer doped with 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)-4H-pyran (DCJTB) were investigated. With appropriate tuning in the film thickness, position, and dopant concentration of the co-doped layer, a white OLED with a luminance yield of 10.02 cd/A with the CIE coordinates of (0.29, 0.33) has been achieved at a bias voltage of 9 V and a luminance level of over 10,000 cd/m2. By introducing the PIN structure with both HIL and bis(10- hydroxybenzo-quinolinato)-beryllium (BeBq2) ETL, the power efficiency of white OLED was improved.

  20. High efficiency organic photovoltaic cells employing hybridized mixed-planar heterojunctions

    Science.gov (United States)

    Xue, Jiangeng; Uchida, Soichi; Rand, Barry P; Forrest, Stephen

    2013-11-19

    A device is provided, having a first electrode, a second electrode, and a photoactive region disposed between the first electrode and the second electrode. The photoactive region includes a first organic layer comprising a mixture of an organic acceptor material and an organic donor material, wherein the first organic layer has a thickness not greater than 0.8 characteristic charge transport lengths, and a second organic layer in direct contact with the first organic layer, wherein: the second organic layer comprises an unmixed layer of the organic acceptor material or the organic donor material of the first organic layer, and the second organic layer has a thickness not less than about 0.1 optical absorption lengths. Preferably, the first organic layer has a thickness not greater than 0.3 characteristic charge transport lengths. Preferably, the second organic layer has a thickness of not less than about 0.2 optical absorption lengths. Embodiments of the invention can be capable of power efficiencies of 2% or greater, and preferably 5% or greater.

  1. High Efficiency Near-Infrared and Semitransparent Non-Fullerene Acceptor Organic Photovoltaic Cells.

    Science.gov (United States)

    Li, Yongxi; Lin, Jiu-Dong; Che, Xiaozhou; Qu, Yue; Liu, Feng; Liao, Liang-Sheng; Forrest, Stephen R

    2017-11-29

    The absence of near-infrared (NIR) solar cells with high open circuit voltage (V oc ) and external quantum efficiency (EQE) has impeded progress toward achieving organic photovoltaic (OPV) power conversion efficiency PCE > 15%. Here we report a small energy gap (1.3 eV), chlorinated nonfullerene acceptor-based solar cell with PCE = 11.2 ± 0.4%, short circuit current of 22.5 ± 0.6 mA cm -2 , V oc = 0.70 ± 0.01 V and fill factor of 0.71 ± 0.02, which is the highest performance reported to date for NIR single junction OPVs. Importantly, the EQE of this NIR solar cell reaches 75%, between 650 and 850 nm while leaving a transparency window between 400 and 600 nm. The semitransparent OPV using an ultrathin (10 nm) Ag cathode shows PCE = 7.1 ± 0.1%, with an average visible transmittance of 43 ± 2%, Commission d'Eclairage chromaticity coordinates of (0.29, 0.32) and a color rendering index of 91 for simulated AM1.5 illumination transmitted through the cell.

  2. Production of a High Efficiency Microbial Flocculant by Proteus mirabilis TJ-1 Using Compound Organic Wastewater

    Science.gov (United States)

    Zhang, Zhiqiang; Xia, Siqing; Zhang, Jiao

    2010-11-01

    The production of a high efficiency microbial flocculant (MBF) by Proteus mirabilis TJ-1 using compound organic wastewater was investigated. To cut down the cost of the MBF production, several nutritive organic wastewaters were selected to replace glucose and peptone as the carbon source and the nitrogen source in the optimized medium of strain TJ-1, respectively. The compound wastewater of the milk candy and the soybean milk was found to be good carbon source and nitrogen source for this strain to produce MBF. The cost-effective culture medium consists of (per liter): 800 mL wastewater of milk candy, 200 mL wastewater of soybean milk, 0.3 g MgSO4ṡ7 H2O, 5 g K2HPO4, 2 g and KH2PO4, pH 7.0. The economic cost for the MBF production can be cut down over a half by using the developed culture medium. Furthermore, the utilization of the two wastewaters in the preparation of culture medium of strain TJ-1 can not only save their big treatment cost, but also realize their resource reuse.

  3. Tackling Energy Loss for High-Efficiency Organic Solar Cells with Integrated Multiple Strategies.

    Science.gov (United States)

    Zuo, Lijian; Shi, Xueliang; Jo, Sae Byeok; Liu, Yun; Lin, Fracis; Jen, Alex K-Y

    2018-04-01

    Limited by the various inherent energy losses from multiple channels, organic solar cells show inferior device performance compared to traditional inorganic photovoltaic techniques, such as silicon and CuInGaSe. To alleviate these fundamental limitations, an integrated multiple strategy is implemented including molecular design, interfacial engineering, optical manipulation, and tandem device construction into one cell. Considering the close correlation among these loss channels, a sophisticated quantification of energy-loss reduction is tracked along with each strategy in a perspective to reach rational overall optimum. A novel nonfullerene acceptor, 6TBA, is synthesized to resolve the thermalization and V OC loss, and another small bandgap nonfullerene acceptor, 4TIC, is used in the back sub-cell to alleviate transmission loss. Tandem architecture design significantly reduces the light absorption loss, and compensates carrier dynamics and thermalization loss. Interfacial engineering further reduces energy loss from carrier dynamics in the tandem architecture. As a result of this concerted effort, a very high power conversion efficiency (13.20%) is obtained. A detailed quantitative analysis on the energy losses confirms that the improved device performance stems from these multiple strategies. The results provide a rational way to explore the ultimate device performance through molecular design and device engineering. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Smooth Growth of Organic Semiconductor Films on Graphene for High-Efficiency Electronics

    NARCIS (Netherlands)

    Hlawacek, G.; Khokhar, F.S.; van Gastel, Raoul; Poelsema, Bene; Teichert, Christian

    2011-01-01

    High-quality thin films of conjugated molecules with smooth interfaces are important to assist the advent of organic electronics. Here, we report on the layer-by-layer growth of the organic semiconductor molecule p-sexiphenyl (6P) on the transparent electrode material graphene. Low energy electron

  5. Highly Efficient p-i-n Type Organic Light-emitting Diodes Using ...

    African Journals Online (AJOL)

    operating voltage of 3.0 V. In addition, impressive characteristics of white .... low voltage drops in the transport layers due to their ... thermal evaporation in high vacuum or organic vapor ... the calibrated silicon photodiode above the OLEDs.

  6. Highly efficient blue and warm white organic light-emitting diodes with a simplified structure

    International Nuclear Information System (INIS)

    Li, Xiang-Long; Chen, Dongcheng; Cai, Xinyi; Liu, Ming; Cao, Yong; Su, Shi-Jian; Ouyang, Xinhua; Ge, Ziyi

    2016-01-01

    Two blue fluorescent emitters were utilized to construct simplified organic light-emitting diodes (OLEDs) and the remarkable difference in device performance was carefully illustrated. A maximum current efficiency of 4.84 cd A"−"1 (corresponding to a quantum efficiency of 4.29%) with a Commission Internationale de l’Eclairage (CIE) coordinate of (0.144, 0.127) was achieved by using N,N-diphenyl-4″-(1-phenyl-1H-benzo[d]imidazol-2-yl)-[1, 1′:4′, 1″-terphenyl]-4-amine (BBPI) as a non-doped emission layer of the simplified blue OLEDs without carrier-transport layers. In addition, simplified fluorescent/phosphorescent (F/P) hybrid warm white OLEDs without carrier-transport layers were fabricated by utilizing BBPI as (1) the blue emitter and (2) the host of a complementary yellow phosphorescent emitter (PO-01). A maximum current efficiency of 36.8 cd A"−"1 and a maximum power efficiency of 38.6 lm W"−"1 were achieved as a result of efficient energy transfer from the host to the guest and good triplet exciton confinement on the phosphorescent molecules. The blue and white OLEDs are among the most efficient simplified fluorescent blue and F/P hybrid white devices, and their performance is even comparable to that of most previously reported complicated multi-layer devices with carrier-transport layers. (paper)

  7. Solution-Processed Phosphorescent Organic Light-Emitting Diodes with Ultralow Driving Voltage and Very High Power Efficiency

    OpenAIRE

    Wang, Shumeng; Wang, Xingdong; Yao, Bing; Zhang, Baohua; Ding, Junqiao; Xie, Zhiyuan; Wang, Lixiang

    2015-01-01

    To realize power efficient solution-processed phosphorescent organic light-emitting diodes (s-PhOLEDs), the corresponding high driving voltage issue should be well solved. To solve it, efforts have been devoted to the exploitation of novel host or interfacial materials. However, the issues of charge trapping of phosphor and/or charge injection barrier are still serious, largely restraining the power efficiency (PE) levels. Herein, with the utilization of an exciplex-forming couple 4, 4?, 4? -...

  8. Highly efficient bilayer interface exciplex for yellow organic light-emitting diode.

    Science.gov (United States)

    Hung, Wen-Yi; Fang, Guan-Cheng; Chang, Yuh-Chia; Kuo, Ting-Yi; Chou, Pi-Tai; Lin, Shih-Wei; Wong, Ken-Tsung

    2013-08-14

    A simple three-layer interfacial-type yellow emission exciplex device with an external quantum efficiency as high as 7.7% has been successfully achieved by combining conformation compatible C3-symmetric hole-transporting TCTA and electron-transporting 3P-T2T. The excellent and balanced charge-transporting properties of TCTA and 3P-T2T and the large energy-levels offset (0.8 eV) of TCTA/3P-T2T interface play important roles for the efficient exciplexes formation, which are effectively confined around the interfacial region due to the high triplet energies (2.85 eV) of TCTA and 3P-T2T. The high-performance OLED was believed to be from the effective harvest of exciplex triplet excitons via reverse intersystem crossing process.

  9. Highly efficient and heavily-doped organic light-emitting devices based on an orange phosphorescent iridium complex

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shunliang; Wang, Qi [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Li, Ming [College of Chemistry, Sichuan University, Chengdu, 610064 (China); Lu, Zhiyun, E-mail: luzhiyun@scu.edu.cn [College of Chemistry, Sichuan University, Chengdu, 610064 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

    2014-10-15

    Heavily doped and highly efficient phosphorescent organic light-emitting devices (PhOLEDs) had been fabricated by utilizing an orange iridium complex, bis[2-(3′,5′-di-tert-butylbiphenyl-4-yl)benzothiazolato-N,C{sup 2'}]iridium(III) (acetylacetonate) [(tbpbt){sub 2}Ir(acac)], as a phosphor. When the doping concentration of [(tbpbt){sub 2}Ir(acac)] reached as high as 15 wt%, the PhOLEDs exhibited a power efficiency, current efficiency, and external quantum efficiency of 24.5 lm/W, 32.1 cd/A, 15.7%, respectively, implying a promising quenching-resistant characteristics of this novel phosphor. Furthermore, the efficient white PhOLEDs had been obtained by employing (tbpbt){sub 2}Ir(acac) as a self-host orange emitter, indicating that (tbpbt){sub 2}Ir(acac) could serve as a promising phosphor to fabricate white organic light-emitting devices with simplified manufacturing process. - Highlights: • Efficient phosphorescent devices were fabricated. • Optimized phosphor doping ratio reached as high as 15 wt%. • The results proved a promising quench-resistant property of the phosphor. • Efficient white devices based on this phosphor as self-host layer had been realized.

  10. Highly efficient and heavily-doped organic light-emitting devices based on an orange phosphorescent iridium complex

    International Nuclear Information System (INIS)

    Zhou, Shunliang; Wang, Qi; Li, Ming; Lu, Zhiyun; Yu, Junsheng

    2014-01-01

    Heavily doped and highly efficient phosphorescent organic light-emitting devices (PhOLEDs) had been fabricated by utilizing an orange iridium complex, bis[2-(3′,5′-di-tert-butylbiphenyl-4-yl)benzothiazolato-N,C 2' ]iridium(III) (acetylacetonate) [(tbpbt) 2 Ir(acac)], as a phosphor. When the doping concentration of [(tbpbt) 2 Ir(acac)] reached as high as 15 wt%, the PhOLEDs exhibited a power efficiency, current efficiency, and external quantum efficiency of 24.5 lm/W, 32.1 cd/A, 15.7%, respectively, implying a promising quenching-resistant characteristics of this novel phosphor. Furthermore, the efficient white PhOLEDs had been obtained by employing (tbpbt) 2 Ir(acac) as a self-host orange emitter, indicating that (tbpbt) 2 Ir(acac) could serve as a promising phosphor to fabricate white organic light-emitting devices with simplified manufacturing process. - Highlights: • Efficient phosphorescent devices were fabricated. • Optimized phosphor doping ratio reached as high as 15 wt%. • The results proved a promising quench-resistant property of the phosphor. • Efficient white devices based on this phosphor as self-host layer had been realized

  11. Composite nanofibers for highly efficient photocatalytic degradation of organic dyes from contaminated water

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Alaa [Department of Materials and NanoPhysics, Royal Institute of Technology (KTH), 16440 Kista, Stockholm (Sweden); Mechanical Design and Production Engineering Department, Cairo University, 12613 Giza (Egypt); Production Engineering and Printing Technology Department, Akhbar El Yom Academy, 12655 Giza (Egypt); El-Sayed, Ramy [Experimental Cancer Medicine, KFC, Novum, Department of laboratory Medicine, Karolinska Institute, 14186 Stockholm (Sweden); Osman, T.A. [Mechanical Design and Production Engineering Department, Cairo University, 12613 Giza (Egypt); Toprak, M.S.; Muhammed, M. [Department of Materials and NanoPhysics, Royal Institute of Technology (KTH), 16440 Kista, Stockholm (Sweden); Uheida, A., E-mail: salam@kth.se [Department of Materials and NanoPhysics, Royal Institute of Technology (KTH), 16440 Kista, Stockholm (Sweden)

    2016-02-15

    In this study highly efficient photocatalyst based on composite nanofibers containing polyacrylonitrile (PAN), carbon nanotubes (CNT), and surface functionalized TiO{sub 2} nanoparticles was developed. The composite nanofibers were fabricated using electrospinning technique followed by chemical crosslinking. The surface modification and morphology changes of the fabricated composite nanofibers were examined through SEM, TEM, and FTIR analysis. The photocatalytic performance of the composite nanofibers for the degradation of model molecules, methylene blue and indigo carmine, under UV irradiation in aqueous solutions was investigated. The results demonstrated that high photodegradation efficiency was obtained in a short time and at low power intensity compared to other reported studies. The effective factors on the degradation of the dyes, such as the amount of catalyst, solution pH and irradiation time were investigated. The experimental kinetic data were fitted using pseudo-first order model. The effect of the composite nanofibers as individual components on the degradation efficiency of MB and IC was evaluated in order to understand the overall photodegradation mechanism. The results obtained showed that all the components possess significant effect on the photodegradation activity of the composite nanofibers. The stability studies demonstrated that the photodegradation efficiency can remain constant at the level of 99% after five consecutive cycles. - Highlights: • Develop effective photocatalyst based on PAN–CNT/TiO{sub 2}–NH{sub 2} composite nanofibers. • High photodegradation efficiency and fast kinetics was obtained. • Regeneration of the composite nanofibers allowed the reuse of these material. • Mechanism of the photocatalytic degradation was proposed. • The flexibility of the composite nanofibers allows use in a continuous operation mode.

  12. Composite nanofibers for highly efficient photocatalytic degradation of organic dyes from contaminated water

    International Nuclear Information System (INIS)

    Mohamed, Alaa; El-Sayed, Ramy; Osman, T.A.; Toprak, M.S.; Muhammed, M.; Uheida, A.

    2016-01-01

    In this study highly efficient photocatalyst based on composite nanofibers containing polyacrylonitrile (PAN), carbon nanotubes (CNT), and surface functionalized TiO 2 nanoparticles was developed. The composite nanofibers were fabricated using electrospinning technique followed by chemical crosslinking. The surface modification and morphology changes of the fabricated composite nanofibers were examined through SEM, TEM, and FTIR analysis. The photocatalytic performance of the composite nanofibers for the degradation of model molecules, methylene blue and indigo carmine, under UV irradiation in aqueous solutions was investigated. The results demonstrated that high photodegradation efficiency was obtained in a short time and at low power intensity compared to other reported studies. The effective factors on the degradation of the dyes, such as the amount of catalyst, solution pH and irradiation time were investigated. The experimental kinetic data were fitted using pseudo-first order model. The effect of the composite nanofibers as individual components on the degradation efficiency of MB and IC was evaluated in order to understand the overall photodegradation mechanism. The results obtained showed that all the components possess significant effect on the photodegradation activity of the composite nanofibers. The stability studies demonstrated that the photodegradation efficiency can remain constant at the level of 99% after five consecutive cycles. - Highlights: • Develop effective photocatalyst based on PAN–CNT/TiO 2 –NH 2 composite nanofibers. • High photodegradation efficiency and fast kinetics was obtained. • Regeneration of the composite nanofibers allowed the reuse of these material. • Mechanism of the photocatalytic degradation was proposed. • The flexibility of the composite nanofibers allows use in a continuous operation mode.

  13. Novel concepts for high-efficiency white organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Gregor

    2007-07-01

    This work deals with novel concepts to realize high efficiency white OLEDs by combining fluorescent blue and phosphorescent green and orange emitters. A key point determining the maximum efficiency possible, as well as the device structure to be chosen to reach high efficiency, is the triplet exciton energy of the fluorescent blue emitter. If its triplet state is lower than that of the phosphorescent emitters, mutual exciton quenching can occur. This problem is solved by the first concept with spatial separation of the fluorescent blue from the phosphorescent emitters by a large-gap exciton blocking layer. To still realize exciton generation on both sides, the interlayer has to be ambipolar. On the other hand, if the triplet exciton energy of the fluorescent blue is higher than that of at least one of the phosphorescent emitters, appropriate arrangement of the emission layers makes a separation layer obsolete, since phosphorescence quenching does not occur anymore. Moreover, the intrinsically non-radiative triplet excitons of the fluorescent blue emitter may be harvested by the phosphor for light emission, which means that even 100% internal quantum efficiency is possible. The last chapter 6 deals with this second concept, where the main issue is to simultaneously achieve exciton harvesting as complete as possible and a balanced white emission spectrum by appropriately distributing singlet and triplet excitons to the used emitters. All emitters used in this work are commercially available and their molecular structure is disclosed in order to make the results transparent. (orig.)

  14. Cyclometalated Iridium(III) Carbene Phosphors for Highly Efficient Blue Organic Light-Emitting Diodes.

    Science.gov (United States)

    Chen, Zhao; Wang, Liqi; Su, Sikai; Zheng, Xingyu; Zhu, Nianyong; Ho, Cheuk-Lam; Chen, Shuming; Wong, Wai-Yeung

    2017-11-22

    Five deep blue carbene-based iridium(III) phosphors were synthesized and characterized. Interestingly, one of them can be fabricated into deep blue, sky blue and white organic light-emitting diodes (OLEDs) through changing the host materials and exciton blocking layers. These deep and sky blue devices exhibit Commission Internationale de l'Éclairage (CIE) coordinates of (0.145, 0.186) and (0.152, 0.277) with external quantum efficiency (EQE) of 15.2% and 9.6%, respectively. The EQE of the deep blue device can be further improved up to 19.0% by choosing a host with suitable energy level of its lowest unoccupied molecular orbital (LUMO).

  15. High-efficiency orange and tandem white organic light-emitting diodes using phosphorescent dyes with horizontally oriented emitting dipoles.

    Science.gov (United States)

    Lee, Sunghun; Shin, Hyun; Kim, Jang-Joo

    2014-09-03

    Tandem white organic light-emitting diodes (WOLEDs) using horizontally oriented phosphorescent dyes in an exciplex-forming co-host are presented, along with an orange OLED. A high external quantum efficiency of 32% is achieved for the orange OLED at 1000 cd m(-2) and the tandem WOLEDs exhibit a high maximum EQE of 54.3% (PE of 63 lm W(-1)). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Highly efficient red fluorescent organic light-emitting diodes by sorbitol-doped PEDOT:PSS

    Science.gov (United States)

    Zheng, Yan-Qiong; Yu, Jun-Le; Wang, Chao; Yang, Fang; Wei, Bin; Zhang, Jian-Hua; Zeng, Cheng-Hui; Yang, Yang

    2018-06-01

    This work shows a promising approach to improve device performance by optimizing the electron transport and hole injection layers for tetraphenyldibenzoperiflanthene (DBP):rubrene-based red fluorescent organic light-emitting diodes (OLEDs). We compared the effect of two electron transport layers (ETLs), and found that the rubrene/bathophenanthroline (Bphen) ETL-based OLED showed a much higher external quantum efficiency (EQE) (4.67%) than the Alq3 ETL-based OLED (EQE of 3.08%). The doping ratio of DBP in rubrene was tuned from 1.0 wt% to 4.5 wt%, and the 1.5 wt%-DBP:rubrene-based OLED demonstrated the highest EQE of 5.24% and lowest turn-on voltage of 2.2 V. Atomic force microscopy images indicated that 1.5 wt% DBP-doped rubrene film exhibited a regular strip shape, and this regular surface was favorable to the hole and electron recombination in the emitting layer. Finally, the sorbitol-doped poly(3, 4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was used to further improve the EQE; doping with 6 wt% sorbitol achieved the highest current efficiency of 7.03 cd A‑1 and an EQE of 7.50%. The significantly enhanced performance implies that the hole injection is a limiting factor for DBP:rubrene-based red fluorescent OLEDs.

  17. Extremely high efficiency phosphorescent organic light-emitting diodes with horizontal emitting dipoles

    Science.gov (United States)

    Kim, Kwon-Hyeon; Moon, Chang-Ki; Lee, Jeong-Hwan; Kim, Jang-Joo

    2014-10-01

    We present the factors influencing the orientation of the phosphorescent dyes in phosphorescent OLEDs. And, we report that an OLED containing a phosphorescent emitter with horizontally oriented dipoles in an exciplex-forming co-host that exhibits an extremely high EQE of 32.3% and power efficiency of 142 lm/W, the highest values ever reported in literature. Furthermore, we experimentally and theoretically correlated the EQE of OLEDs to the PL quantum yield and the horizontal dipole ratio of phosphorescent dyes using three different dyes.

  18. Highly efficient hybrid energy generator: coupled organic photovoltaic device and randomly oriented electrospun poly(vinylidene fluoride) nanofiber.

    Science.gov (United States)

    Park, Boongik; Lee, Kihwan; Park, Jongjin; Kim, Jongmin; Kim, Ohyun

    2013-03-01

    A hybrid architecture consisting of an inverted organic photovoltaic device and a randomly-oriented electrospun PVDF piezoelectric device was fabricated as a highly-efficient energy generator. It uses the inverted photovoltaic device with coupled electrospun PVDF nanofibers as tandem structure to convert solar and mechanical vibrations energy to electricity simultaneously or individually. The power conversion efficiency of the photovoltaic device was also significantly improved up to 4.72% by optimized processes such as intrinsic ZnO, MoO3 and active layer. A simple electrospinning method with the two electrode technique was adopted to achieve a high voltage of - 300 mV in PVDF piezoelectric fibers. Highly-efficient HEG using voltage adder circuit provides the conceptual possibility of realizing multi-functional energy generator whenever and wherever various energy sources are available.

  19. High-efficiency and heavily doped organic light-emitting devices based on quench-resistant red iridium complex

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qi [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zhao, Juan; Wang, Jun [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Li, Ming [College of Chemistry, Sichuan University, Chengdu 610064 (China); Lu, Zhiyun, E-mail: luzhiyun@scu.edu.cn [College of Chemistry, Sichuan University, Chengdu 610064 (China)

    2013-02-15

    Highly efficient red phosphorescent organic light-emitting devices had been fabricated using a new iridium complex, bis[2-(9,9-dimethyl-9H-fluoren-2-yl) benzothiazolato-N,C{sup 2'}]iridium(III) (acetylacetonate) [(fbt){sub 2}Ir(acac)] as phosphor. With a high doping concentration of 15 wt%, the device exhibited a maximum luminance efficiency, power efficiency and external quantum efficiency (EQE) of 35.2 cd/A, 21.3 lm/W, 18.2%, respectively, indicating an excellent quench-resistant property of (fbt){sub 2}Ir(acac). The results are appealing towards the development of 'easy-to-make' OLEDs. It has been demonstrated that the high efficiency arises from more balanced charge carriers in the emissive layer. - Highlight: Black-Right-Pointing-Pointer We obtained efficient OLEDs based on newly synthesized quench-resistant phosphor. Black-Right-Pointing-Pointer Peak performance was obtained with 15 wt% (fbt){sub 2}Ir(acac) doped device. Black-Right-Pointing-Pointer Our devices gave one of the best performance among heavily-doped red devices. Black-Right-Pointing-Pointer Balanced carrier transport is crucial for the high performance of our devices.

  20. Importance of the Donor:Fullerene intermolecular arrangement for high-efficiency organic photovoltaics

    KAUST Repository

    Graham, Kenneth; Cabanetos, Clement; Jahnke, Justin P.; Idso, Matthew N.; El Labban, Abdulrahman; Ngongang Ndjawa, Guy Olivier; Heumueller, Thomas; Vandewal, Koen; Salleo, Alberto; Chmelka, Bradley F.; Amassian, Aram; Beaujuge, Pierre; McGehee, Michael D.

    2014-01-01

    The performance of organic photovoltaic (OPV) material systems are hypothesized to depend strongly on the intermolecular arrangements at the donor:fullerene interfaces. A review of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis of reported polymer donor materials wherein the same conjugated backbone was used with varying alkyl substituents, supports this hypothesis. Specifically, the literature shows that higher-performing donor-acceptor type polymers generally have acceptor moieties that are sterically accessible for interactions with the fullerene derivative, whereas the corresponding donor moieties tend to have branched alkyl substituents that sterically hinder interactions with the fullerene. To further explore the idea that the most beneficial polymer:fullerene arrangement involves the fullerene docking with the acceptor moiety, a family of benzo[1,2-b:4,5-b]dithiophene-thieno[3,4-c]pyrrole-4,6-dione polymers (PBDTTPD derivatives) was synthesized and tested in a variety of PV device types with vastly different aggregation states of the polymer. In agreement with our hypothesis, the PBDTTPD derivative with a more sterically accessible acceptor moiety and a more sterically hindered donor moiety shows the highest performance in bulk-heterojunction, bilayer, and low-polymer concentration PV devices where fullerene derivatives serve as the electron-accepting materials. Furthermore, external quantum efficiency measurements of the charge-transfer state and solid-state two-dimensional (2D) 13C{1H} heteronuclear correlation (HETCOR) NMR analyses support that a specific polymer:fullerene arrangement is present for the highest performing PBDTTPD derivative, in which the fullerene is in closer proximity to the acceptor moiety of the polymer. This work demonstrates that the polymer:fullerene arrangement and resulting intermolecular interactions may be key factors in determining the performance of OPV material systems

  1. Importance of the Donor:Fullerene intermolecular arrangement for high-efficiency organic photovoltaics

    KAUST Repository

    Graham, Kenneth

    2014-07-09

    The performance of organic photovoltaic (OPV) material systems are hypothesized to depend strongly on the intermolecular arrangements at the donor:fullerene interfaces. A review of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis of reported polymer donor materials wherein the same conjugated backbone was used with varying alkyl substituents, supports this hypothesis. Specifically, the literature shows that higher-performing donor-acceptor type polymers generally have acceptor moieties that are sterically accessible for interactions with the fullerene derivative, whereas the corresponding donor moieties tend to have branched alkyl substituents that sterically hinder interactions with the fullerene. To further explore the idea that the most beneficial polymer:fullerene arrangement involves the fullerene docking with the acceptor moiety, a family of benzo[1,2-b:4,5-b]dithiophene-thieno[3,4-c]pyrrole-4,6-dione polymers (PBDTTPD derivatives) was synthesized and tested in a variety of PV device types with vastly different aggregation states of the polymer. In agreement with our hypothesis, the PBDTTPD derivative with a more sterically accessible acceptor moiety and a more sterically hindered donor moiety shows the highest performance in bulk-heterojunction, bilayer, and low-polymer concentration PV devices where fullerene derivatives serve as the electron-accepting materials. Furthermore, external quantum efficiency measurements of the charge-transfer state and solid-state two-dimensional (2D) 13C{1H} heteronuclear correlation (HETCOR) NMR analyses support that a specific polymer:fullerene arrangement is present for the highest performing PBDTTPD derivative, in which the fullerene is in closer proximity to the acceptor moiety of the polymer. This work demonstrates that the polymer:fullerene arrangement and resulting intermolecular interactions may be key factors in determining the performance of OPV material systems

  2. Highly Efficient Red and White Organic Light-Emitting Diodes with External Quantum Efficiency beyond 20% by Employing Pyridylimidazole-Based Metallophosphors.

    Science.gov (United States)

    Miao, Yanqin; Tao, Peng; Wang, Kexiang; Li, Hongxin; Zhao, Bo; Gao, Long; Wang, Hua; Xu, Bingshe; Zhao, Qiang

    2017-11-01

    Two highly efficient red neutral iridium(III) complexes, Ir1 and Ir2, were rationally designed and synthesized by selecting two pyridylimidazole derivatives as the ancillary ligands. Both Ir1 and Ir2 show nearly the same photoluminescence emission with the maximum peak at 595 nm (shoulder band at about 638 nm) and achieve high solution quantum yields of up to 0.47 for Ir1 and 0.57 for Ir2. Employing Ir1 and Ir2 as emitters, the fabricated red organic light-emitting diodes (OLEDs) show outstanding performance with the maximum external quantum efficiency (EQE), current efficiency (CE), and power efficiency (PE) of 20.98%, 33.04 cd/A, and 33.08 lm/W for the Ir1-based device and 22.15%, 36.89 cd/A, and 35.85 lm/W for the Ir2-based device, respectively. Furthermore, using Ir2 as red emitter, a trichromatic hybrid white OLED, showing good warm white emission with low correlated color temperature of white device also realizes excellent device efficiencies with the maximum EQE, CE, and PE reaching 22.74%, 44.77 cd/A, and 46.89 lm/W, respectively. Such high electroluminescence performance for red and white OLEDs indicates that Ir1 and Ir2 as efficient red phosphors have great potential for future OLED displays and lightings applications.

  3. Silver nanowire-graphene hybrid transparent conductive electrodes for highly efficient inverted organic solar cells

    Science.gov (United States)

    Ye, Neng; Yan, Jielin; Xie, Shuang; Kong, Yuhan; Liang, Tao; Chen, Hongzheng; Xu, Mingsheng

    2017-07-01

    Silver nanowires (AgNWs) and graphene are both promising candidates as a transparent conductive electrode (TCE) to replace expensive and fragile indium tin oxide (ITO) TCE. A synergistically optimized performance is expected when the advantages of AgNWs and graphene are combined. In this paper, the AgNW-graphene hybrid electrode is constructed by depositing a graphene layer on top of the network of AgNWs. Compared with the pristine AgNWs electrode, the AgNW-graphene TCE exhibits reduced sheet resistance, lower surface roughness, excellent long-term stability, and corrosion resistance in corrosive liquids. The graphene layer covering the AgNWs provides additional conduction pathways for electron transport and collection by the electrode. Benefiting from these advantages of the hybrid electrodes, we achieve a power conversion efficiency of 8.12% of inverted organic solar cells using PTB7:PC71BM as the active layer, which is compared to that of the solar cells based on standard ITO TCE but about 10% higher than that based on AgNWs TCE.

  4. Chitin/clay microspheres with hierarchical architecture for highly efficient removal of organic dyes.

    Science.gov (United States)

    Xu, Rui; Mao, Jie; Peng, Na; Luo, Xiaogang; Chang, Chunyu

    2018-05-15

    Numerous adsorbents have been reported for efficient removal of dye from water, but the high cost raw materials and complicated fabrication process limit their practical applications. Herein, novel nanocomposite microspheres were fabricated from chitin and clay by a simple thermally induced sol-gel transition. Clay nanosheets were uniformly embedded in a nanofiber weaved chitin microsphere matrix, leading to their hierarchical architecture. Benefiting from this unique structure, microspheres could efficiently remove methylene blue (MB) through a spontaneous physic-sorption process which fit well with pseudo-second-order and Langmuir isotherm models. The maximal values of adsorption capability obtained by calculation and experiment were 152.2 and 156.7 mg g -1 , respectively. Chitin/clay microspheres (CCM2) could remove 99.99% MB from its aqueous solution (10 mg g -1 ) within 20 min. These findings provide insight into a new strategy for fabrication of dye adsorbents with hierarchical structure from low cost raw materials. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Highly Efficient White Organic Light Emitting Diodes Using New Blue Fluorescence Emitter.

    Science.gov (United States)

    Kim, Seungho; Kim, Beomjin; Lee, Jaehyun; Yu, Young-Jun; Park, Jongwook

    2015-07-01

    Two different emitting compounds, 1-[1,1';3',1"]Terphenyl-5'-yl-6-(10-[1,1';3',1"]terpheny-5'-yl- anthracen-9-yl)-pyrene (TP-AP-TP) and Poly-phenylene vinylene derivative (PDY 132) were used to white OLED device. By incorporating adjacent blue and yellow emitting layers in a multi-layered structure, highly efficient white emission has been attained. The device was fabricated with a hybrid configuration structure: ITO/PEDOT (40 nm)/PDY-132 (8-50 nm)/ NPB (10 nm)/TP-AP-TP (30 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm). After fixing TP-AP-TP thickness of 30 nm by evaporation, PDY-132 thickness varied with 8, 15, 35, and 50 nm by spin coating in device. The luminance efficiency of the white devices at 10 mA/cm2 were 2.93 cd/A-6.55 cd/A. One of white devices showed 6.55 cd/A and white color of (0.290, 0.331).

  6. Highly nonlinear organic crystal OHQ-T for efficient ultra-broadband terahertz wave generation beyond 10 THz.

    Science.gov (United States)

    Kang, Bong Joo; Baek, In Hyung; Lee, Seung-Heon; Kim, Won Tae; Lee, Seung-Jun; Jeong, Young Uk; Kwon, O-Pil; Rotermund, Fabian

    2016-05-16

    We report on efficient generation of ultra-broadband terahertz (THz) waves via optical rectification in a novel nonlinear organic crystal with acentric core structure, i.e. 2-(4-hydroxystyryl)-1-methylquinolinium 4-methylbenzenesulfonate (OHQ-T), which possesses an ideal molecular structure leading to a maximized nonlinear optical response for near-infrared-pumped THz wave generation. By systematic studies on wavelength-dependent phase-matching conditions in OHQ-T crystals of different thicknesses we are able to generate coherent THz waves with a high peak-to-peak electric field amplitude of up to 650 kV/cm and an upper cut-off frequency beyond 10 THz. High optical-to-THz conversion efficiency of 0.31% is achieved by efficient index matching with a selective pumping at 1300 nm.

  7. FODA: a novel efficient multiple access protocol for highly dynamic self-organizing networks

    Science.gov (United States)

    Li, Hantao; Liu, Kai; Zhang, Jun

    2005-11-01

    Based on the concept of contention reservation for polling transmission and collision prevention strategy for collision resolution, a fair on-demand access (FODA) protocol for supporting node mobility and multihop architecture in highly dynamic self-organizing networks is proposed. In the protocol, a distributed clustering network architecture formed by self-organizing algorithm and a main idea of reserving channel resources to get polling service are adopted, so that the hidden terminal (HT) and exposed terminal (ET) problems existed in traffic transmission due to multihop architecture and wireless transmission can be eliminated completely. In addition, an improved collision prevention scheme based on binary countdown algorithm (BCA), called fair collision prevention (FCP) algorithm, is proposed to greatly eliminate unfair phenomena existed in contention access of newly active ordinary nodes and completely resolve access collisions. Finally, the performance comparison of the FODA protocol with carrier sense multiple access with collision avoidance (CSMA/CA) and polling protocols by OPNET simulation are presented. Simulation results show that the FODA protocol can overcome the disadvantages of CSMA/CA and polling protocols, and achieve higher throughput, lower average message delay and less average message dropping rate.

  8. A series of dithienobenzodithiophene based small molecules for highly efficient organic solar cells

    Institute of Scientific and Technical Information of China (English)

    Huanran Feng; Miaomiao Li; Wang Ni; Bin Kan; Yunchuang Wang; Yamin Zhang; Hongtao Zhang; Xiangjian Wan; Yongsheng Chen

    2017-01-01

    Three acceptor-donor-acceptor(A-D-A) small molecules DCAODTBDT,DRDTBDT and DTBDTBDT using dithieno[2,3-d:2’,3’-d’]benzo[l,2-b:4,5-b’]dithiophene as the central building block,octyl cyanoacetate,3-octylrhodanine and thiobarbituric acid as the end groups were designed and synthesized as donor materials in solution-processed photovoltaic cells(OPVs).The impacts of these different electron withdrawing end groups on the photophysical properties,energy levels,charge carrier mobility,morphologies of blend films,and their photovoltaic properties have been systematically investigated.OPVs device based on DRDTBDT gave the best power conversion efficiency(PCE) of 8.34%,which was significantly higher than that based on DCAODTBDT(4.83%) or DTBDTBDT(3.39%).These results indicate that rather dedicated and balanced consideration of absorption,energy levels,morphology,mobility,etc.for the design of small-molecule-based OPVs(SM-OPVs)and systematic investigations are highly needed to achieve high performance for SM-OPVs.

  9. A series of dithienobenzodithiophene based small molecules for highly efficient organic solar cells

    Institute of Scientific and Technical Information of China (English)

    Huanran Feng; Miaomiao Li; Wang Ni; Bin Kan; Yunchuang Wang; Yamin Zhang; Hongtao Zhang; Xiangjian Wan; Yongsheng Chen

    2017-01-01

    Three acceptor-donor-acceptor (A-D-A) small molecules DCAODTBDT,DRDTBDT and DTBDTBDT using dithieno[2,3-d∶2',3'-d']benzo[1,2-b∶4,5-b']dithiophene as the central building block,octyl cyanoacetate,3-octylrhodanine and thiobarbituric acid as the end groups were designed and synthesized as donor materials in solution-processed photovoltaic cells (OPVs).The impacts of these different electron withdrawing end groups on the photophysical properties,energy levels,charge carrier mobility,morphologies of blend films,and their photovoltaic properties have been systematically investigated.OPVs device based on DRDTBDT gave the best power conversion efficiency (PCE) of 8.34%,which was significantly higher than that based on DCAODTBDT (4.83%) or DTBDTBDT (3.39%).These results indicate that rather dedicated and balanced consideration of absorption,energy levels,morphology,mobility,etc.for the design of small-molecule-based OPVs (SM-OPVs) and systematic investigations are highly needed to achieve high performance for SM-OPVs.

  10. Highly efficient exciplex organic light-emitting diodes using thermally activated delayed fluorescent emitters as donor and acceptor materials

    Science.gov (United States)

    Jeon, Sang Kyu; Yook, Kyoung Soo; Lee, Jun Yeob

    2016-06-01

    Highly efficient exciplex type organic light-emitting diodes were developed using thermally activated delayed fluorescent emitters as donors and acceptors of an exciplex. Blue emitting bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (DMAC-DPS) was a donor and 9,9‧-(5-(4,6-diphenyl-1,3,5-triazin-2-yl)-1,3-phenylene)bis(9H-carbazole) (DDCzTrz) and 9,9‧,9″-(5-(4,6-diphenyl-1,3,5-triazin-2-yl)benzene-1,2,3-triyl)tris(9H-carbazole) (TCzTrz) were acceptor materials. The exciplexes of DMAC-DPS:TCzTrz and DMAC-DPS:DDCzTrz resulted in high photoluminescence quantum yield and high quantum efficiency in the green exciplex organic light-emitting diodes. High quantum efficiencies of 13.4% and 15.3% were obtained in the DMAC-DPS:DDCzTrz and DMAC-DPS:TCzTrz exciplex devices.

  11. Using an ultra-thin non-doped orange emission layer to realize high efficiency white organic light-emitting diodes with low efficiency roll-off

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Liping; Chen, Jiangshan; Ma, Dongge, E-mail: mdg1014@ciac.ac.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate University of the Chinese Academy of Sciences, Changchun 130022 (China); Zhao, Yongbiao [Luminous Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, Singapore 639798 (Singapore); Zhang, Hongmei [Department of Materials Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023 (China)

    2014-06-28

    By adopting an ultra-thin non-doped orange emission layer sandwiched between two blue emission layers, high efficiency white organic light-emitting diodes (WOLEDs) with reduced efficiency roll-off were fabricated. The optimized devices show a balanced white emission with Internationale de L'Eclairage of (0.41, 0.44) at the luminance of 1000 cd/m{sup 2}, and the maximum power efficiency, current efficiency (CE), and external quantum efficiency reach 63.2 lm/W, 59.3 cd/A, and 23.1%, which slightly shift to 53.4 lm/W, 57.1 cd/A, and 22.2% at 1000 cd/m{sup 2}, respectively, showing low efficiency roll-off. Detailed investigations on the recombination zone and the transient electroluminescence (EL) clearly reveal the EL processes of the ultra-thin non-doped orange emission layer in WOLEDs.

  12. Enhanced energy conversion efficiency from high strength synthetic organic wastewater by sequential dark fermentative hydrogen production and algal lipid accumulation.

    Science.gov (United States)

    Ren, Hong-Yu; Liu, Bing-Feng; Kong, Fanying; Zhao, Lei; Xing, Defeng; Ren, Nan-Qi

    2014-04-01

    A two-stage process of sequential dark fermentative hydrogen production and microalgal cultivation was applied to enhance the energy conversion efficiency from high strength synthetic organic wastewater. Ethanol fermentation bacterium Ethanoligenens harbinense B49 was used as hydrogen producer, and the energy conversion efficiency and chemical oxygen demand (COD) removal efficiency reached 18.6% and 28.3% in dark fermentation. Acetate was the main soluble product in dark fermentative effluent, which was further utilized by microalga Scenedesmus sp. R-16. The final algal biomass concentration reached 1.98gL(-1), and the algal biomass was rich in lipid (40.9%) and low in protein (23.3%) and carbohydrate (11.9%). Compared with single dark fermentation stage, the energy conversion efficiency and COD removal efficiency of two-stage system remarkably increased 101% and 131%, respectively. This research provides a new approach for efficient energy production and wastewater treatment using a two-stage process combining dark fermentation and algal cultivation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Development of a Highly Efficient Hybrid White Organic-Light-Emitting Diode with a Single Emission Layer by Solution Processing.

    Science.gov (United States)

    Wu, Jun-Yi; Chen, Show-An

    2018-02-07

    We use a mixed host, 2,6-bis[3-(carbazol-9-yl)phenyl]pyridine blended with 20 wt % tris(4-carbazoyl-9-ylphenyl)amine, to lower the hole-injection barrier, along with the bipolar and high-photoluminescence-quantum-yield (Φ p = 84%), blue thermally activated delay fluorescence (TADF) material of 9,9-dimethyl-9,10-dihydroacridine-2,4,6-triphenyl-1,3,5-triazine (DMAC-TRZ) as a blue dopant to compose the emission layer for the fabrication of a TADF blue organic-light-emitting diode (BOLED). The device is highly efficient with the following performance parameters: maximum brightness (B max ) = 57586 cd/m 2 , maximum current efficiency (CE max ) = 35.3 cd/A, maximum power efficiency (PE max ) = 21.4 lm/W, maximum external quantum efficiency (EQE max ) = 14.1%, and CIE coordinates (0.18, 0.42). This device has the best performance recorded among the reported solution-processed TADF BOLEDs and has a low efficiency roll-off: at brightness values of 1000 and 5000 cd/m 2 , its CEs are close, being 35.1 and 30.1 cd/A, respectively. Upon further doping of the red phosphor Ir(dpm)PQ 2 (emission peak λ max = 595 nm) into the blue emission layer, we obtained a TADF-phosphor hybrid white organic-light-emitting diode (T-P hybrid WOLED) with high performance: B max = 43594 cd/m 2 , CE max = 28.8 cd/A, PE max = 18.1 lm/W, and CIE coordinates (0.38, 0.44). This B max = 43594 cd/m 2 is better than that of the vacuum-deposited WOLED with a blue TADF emitter, 10000 cd/m 2 . This is also the first report on a T-P hybrid WOLED with a solution-processed emitting layer.

  14. Color-tunable and high-efficiency organic light-emitting diode by adjusting exciton bilateral migration zone

    Science.gov (United States)

    Liu, Shengqiang; Wu, Ruofan; Huang, Jiang; Yu, Junsheng

    2013-09-01

    A voltage-controlled color-tunable and high-efficiency organic light-emitting diode (OLED) by inserting 16-nm N,N'-dicarbazolyl-3,5-benzene (mCP) interlayer between two complementary emitting layers (EMLs) was fabricated. The OLED emitted multicolor ranging from blue (77.4 cd/A @ 6 V), white (70.4 cd/A @ 7 V), to yellow (33.7 cd/A @ 9 V) with voltage variation. An equivalent model was proposed to reveal the color-tunable and high-efficiency emission of OLEDs, resulting from the swing of exciton bilateral migration zone near mCP/blue-EML interface. Also, the model was verified with a theoretical arithmetic using single-EML OLEDs to disclose the crucial role of mCP exciton adjusting layer.

  15. Architectures and criteria for the design of high efficiency organic photovoltaic cells

    Science.gov (United States)

    Rand, Barry; Forrest, Stephen R; Pendergrast Burk, Diane

    2015-03-31

    A method for fabricating an organic photovoltaic cell includes providing a first electrode; depositing a series of at least seven layers onto the first electrode, each layer consisting essentially of a different organic semiconductor material, the organic semiconductor material of at least an intermediate layer of the sequence being a photoconductive material; and depositing a second electrode onto the sequence of at least seven layers. One of the first electrode and the second electrode is an anode and the other is a cathode. The organic semiconductor materials of the series of at least seven layers are arranged to provide a sequence of decreasing lowest unoccupied molecular orbitals (LUMOs) and a sequence of decreasing highest occupied molecular orbitals (HOMOs) across the series from the anode to the cathode.

  16. Oxadiazole-Based Highly Efficient Bipolar Fluorescent Emitters for Organic Light-Emitting Diodes

    Directory of Open Access Journals (Sweden)

    Qiong Wu

    2018-04-01

    Full Text Available In this study, a series of bipolar fluorescence emitters named 2DPAc-OXD, DPAc-OXD, 2PTZ-OXD and PTZ-OXD were designed and synthesized with excellent yields. The characterization of materials was investigated by using nuclear magnetic resonance (NMR (1H, 13C, mass spectrometry and thermogravimetric analysis (TGA. To investigate device efficiencies, two different OLED devices (Device 1, Device 2 were fabricated with two different host materials (Bepp2, DPEPO. The Device 2 with 2PTZ-OXD as fluorescent emitter exhibited excellent power and current efficiencies of 6.88 Lm/W and 10.10 cd/A, respectively. The external quantum efficiency of 2PTZ-OXD was around 3.99% for Device 2. The overall device properties of phenothiazine donor were better than acridine derivatives.

  17. Photoinduced Field-Effect Passivation from Negative Carrier Accumulation for High-Efficiency Silicon/Organic Heterojunction Solar Cells.

    Science.gov (United States)

    Liu, Zhaolang; Yang, Zhenhai; Wu, Sudong; Zhu, Juye; Guo, Wei; Sheng, Jiang; Ye, Jichun; Cui, Yi

    2017-12-26

    Carrier recombination and light management of the dopant-free silicon/organic heterojunction solar cells (HSCs) based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) are the critical factors in developing high-efficiency photovoltaic devices. However, the traditional passivation technologies can hardly provide efficient surface passivation on the front surface of Si. In this study, a photoinduced electric field was induced in a bilayer antireflective coating (ARC) of polydimethylsiloxane (PDMS) and titanium oxide (TiO 2 ) films, due to formation of an accumulation layer of negative carriers (O 2 - species) under UV (sunlight) illumination. This photoinduced field not only suppressed the silicon surface recombination but also enhanced the built-in potential of HSCs with 84 mV increment. In addition, this photoactive ARC also displayed the outstanding light-trapping capability. The front PEDOT:PSS/Si HSC with the saturated O 2 - received a champion PCE of 15.51% under AM 1.5 simulated sunlight illumination. It was clearly demonstrated that the photoinduced electric field was a simple, efficient, and low-cost method for the surface passivation and contributed to achieve a high efficiency when applied in the Si/PEDOT:PSS HSCs.

  18. Highly efficient inverted top emitting organic light emitting diodes using a transparent top electrode with color stability on viewing angle

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung-Bum; Lee, Jeong-Hwan; Moon, Chang-Ki; Kim, Jang-Joo, E-mail: jjkim@snu.ac.kr [Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2014-02-17

    We report a highly efficient phosphorescent green inverted top emitting organic light emitting diode with excellent color stability by using the 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile/indium zinc oxide top electrode and bis(2-phenylpyridine)iridium(III) acetylacetonate as the emitter in an exciplex forming co-host system. The device shows a high external quantum efficiency of 23.4% at 1000 cd/m{sup 2} corresponding to a current efficiency of 110 cd/A, low efficiency roll-off with 21% at 10 000 cd/m{sup 2} and low turn on voltage of 2.4 V. Especially, the device showed very small color change with the variation of Δx = 0.02, Δy = 0.02 in the CIE 1931 coordinates as the viewing angle changes from 0° to 60°. The performance of the device is superior to that of the metal/metal cavity structured device.

  19. Highly Efficient White Organic Light-Emitting Diodes with Ultrathin Emissive Layers and a Spacer-Free Structure

    Science.gov (United States)

    Wu, Shengfan; Li, Sihua; Sun, Qi; Huang, Chenchao; Fung, Man-Keung

    2016-05-01

    Ultrathin emissive layers (UEMLs) of phosphorescent materials with a layer thickness of less than 0.3 nm were introduced for high-efficiency organic light-emitting diodes (OLEDs). All the UEMLs for white OLEDs can be prepared without the use of interlayers or spacers. Compared with devices fabricated with interlayers inserted in-between the UEMLs, our spacer-free structure not only significantly improves device efficiency, but also simplifies the fabrication process, thus it has a great potential in lowering the cost of OLED panels. In addition, its spacer-free structure decreases the number of interfaces which often introduce unnecessary energy barriers in these devices. In the present work, UEMLs of red, green and blue-emitting phosphorescent materials and yellow and blue phosphorescent emitters are utilized for the demonstration of spacer-free white OLEDs. Upon optimization of the device structure, we demonstrated spacer-free and simple-structured white-emitting OLEDs with a good device performance. The current and power efficiencies of our white-emitting devices are as high as 56.0 cd/A and 55.5 lm/W, respectively. These efficiencies are the highest ever reported for OLEDs fabricated with the UEML approach.

  20. Buried MoO x/Ag Electrode Enables High-Efficiency Organic/Silicon Heterojunction Solar Cells with a High Fill Factor.

    Science.gov (United States)

    Xia, Zhouhui; Gao, Peng; Sun, Teng; Wu, Haihua; Tan, Yeshu; Song, Tao; Lee, Shuit-Tong; Sun, Baoquan

    2018-04-25

    Silicon (Si)/organic heterojunction solar cells based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and n-type Si have attracted wide interests because they promise cost-effectiveness and high-efficiency. However, the limited conductivity of PEDOT:PSS leads to an inefficient hole transport efficiency for the heterojunction device. Therefore, a high dense top-contact metal grid electrode is required to assure the efficient charge collection efficiency. Unfortunately, the large metal grid coverage ratio electrode would lead to undesirable optical loss. Here, we develop a strategy to balance PEDOT:PSS conductivity and grid optical transmittance via a buried molybdenum oxide/silver grid electrode. In addition, the grid electrode coverage ratio is optimized to reduce its light shading effect. The buried electrode dramatically reduces the device series resistance, which leads to a higher fill factor (FF). With the optimized buried electrode, a record FF of 80% is achieved for flat Si/PEDOT:PSS heterojunction devices. With further enhancement adhesion between the PEDOT:PSS film and Si substrate by a chemical cross-linkable silance, a power conversion efficiency of 16.3% for organic/textured Si heterojunction devices is achieved. Our results provide a path to overcome the inferior organic semiconductor property to enhance the organic/Si heterojunction solar cell.

  1. Extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters by supercritical carbon dioxide

    International Nuclear Information System (INIS)

    Schilling, J.B.

    1997-09-01

    Supercritical fluid extraction (SFE) using unmodified carbon dioxide has been explored as an alternative method for the extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters. HEPA filters provide the final stage of containment on many exhaust systems in US Department of Energy (DOE) facilities by preventing the escape of chemical and radioactive materials entrained in the exhausted air. The efficiency of the filters is tested by the manufacturer and DOE using dioctylphthalate (DOP), a substance regulated by the US Environmental Protection Agency under the Resource Conservation and Recovery Act. Therefore, the filters must be analyzed for semivolatile organics before disposal. Ninety-eight acid, base, and neutral semivolatile organics were spiked onto blank HEPA material and extracted using SFE, Soxhlet, automated Soxhlet, and sonication techniques. The SFE conditions were optimized using a Dionex SFE-703 instrument. Average recoveries for the 98 semivolatile compounds are 82.7% for Soxhlet, 74.0% for sonication, 70.2% for SFE, and 62.9% for Soxtec. Supercritical fluid extraction reduces the extraction solvent volume to 10--15 mL, a factor of 20--30 less than Soxhlet and more than 5 times less than Soxtec and sonication. Extraction times of 30--45 min are used compared to 16--18 h for Soxhlet extraction

  2. Compositional engineering of acceptors for highly efficient bulk heterojunction hybrid organic solar cells.

    Science.gov (United States)

    Amber Yousaf, S; Ikram, M; Ali, S

    2018-10-01

    The wet chemical synthesis of chromium oxide (Cr 2 O 3 ) nanoparticles (NPs) and its application in active layer of inverted bulk heterojunction organic solar cells is documented in this research. Chromium oxide NPs of 10-30 nm size range having a band gap of 2.9 eV were successfully synthesized. These NPs were used in inverted organic solar cells in amalgamation with P3HT:PCBM and PTB7:PCBM polymers. The fabricated hybrid devices improves PCE significantly for P3HT:PCBM and PTB7:PCBM systems. The photophysical energy levels, optoelectrical properties and microscopic images have been systematically studied for the fabricated devices. The introduction of Cr 2 O 3 nanoparticles (NPs) enhances light harvesting and tunes energy levels into improved electrical parameters. A clear red shift and improved absorption have been observed for ternary blended devices compared to that observed with controlled organic solar cells. Apparently, when the amount of NPs in the binary polymer blend exceeds the required optimum level, there is a breakdown of the bulk heterojunction leading to lowering of the optical and electrical performance of the devices. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Alternative p-doped hole transport material for low operating voltage and high efficiency organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Murawski, Caroline, E-mail: caroline.murawski@iapp.de; Fuchs, Cornelius; Hofmann, Simone; Leo, Karl [Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr-Str. 1, 01062 Dresden (Germany); Gather, Malte C. [Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr-Str. 1, 01062 Dresden (Germany); SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS Scotland (United Kingdom)

    2014-09-15

    We investigate the properties of N,N′-[(Diphenyl-N,N′-bis)9,9,-dimethyl-fluoren-2-yl]-benzidine (BF-DPB) as hole transport material (HTL) in organic light-emitting diodes (OLEDs) and compare BF-DPB to the commonly used HTLs N,N,N′,N′-tetrakis(4-methoxyphenyl)-benzidine (MeO-TPD), 2,2′,7,7′-tetrakis(N,N′-di-p-methylphenylamino)-9,9′-spirobifluorene (Spiro-TTB), and N,N′-di(naphtalene-1-yl)-N,N′-diphenylbenzidine (NPB). The influence of 2,2′-(perfluoronaphthalene-2,6-diylidene)dimalononitrile (F6-TCNNQ p-dopant) concentration in BF-DPB on the operation voltage and efficiency of red and green phosphorescent OLEDs is studied; best results are achieved at 4 wt. % doping. Without any light extraction structure, BF-DPB based red (green) OLEDs achieve a luminous efficacy of 35 .1 lm/W (74 .0 lm/W) at 1000 cd/m{sup 2} and reach a very high brightness of 10 000 cd/m{sup 2} at a very low voltage of 3.2 V (3.1 V). We attribute this exceptionally low driving voltage to the high ionization potential of BF-DPB which enables more efficient hole injection from BF-DPB to the adjacent electron blocking layer. The high efficiency and low driving voltage lead to a significantly lower luminous efficacy roll-off compared to the other compounds and render BF-DPB an excellent HTL material for highly efficient OLEDs.

  4. Solution-processed small molecules as mixed host for highly efficient blue and white phosphorescent organic light-emitting diodes.

    Science.gov (United States)

    Fu, Qiang; Chen, Jiangshan; Shi, Changsheng; Ma, Dongge

    2012-12-01

    The widely used hole-transporting host 4,4',4″-tris(N-carbazolyl)-triphenylamine (TCTA) blended with either a hole-transporting or an electron-transporting small-molecule material as a mixed-host was investigated in the phosphorescent organic light-emitting diodes (OLEDs) fabricated by the low-cost solution-process. The performance of the solution-processed OLEDs was found to be very sensitive to the composition of the mixed-host systems. The incorporation of the hole-transporting 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) into TCTA as the mixed-host was demonstrated to greatly reduce the driving voltage and thus enhance the efficiency due to the improvement of hole injection and transport. On the basis of the mixed-host of TCTA:TAPC, we successfully fabricated low driving voltage and high efficiency blue and white phosphorescent OLEDs. A maximum forward viewing current efficiency of 32.0 cd/A and power efficiency of 25.9 lm/W were obtained in the optimized mixed-host blue OLED, which remained at 29.6 cd/A and 19.1 lm/W at the luminance of 1000 cd/m(2) with a driving voltage as low as 4.9 V. The maximum efficiencies of 37.1 cd/A and 32.1 lm/W were achieved in a single emissive layer white OLED based on the TCTA:TAPC mixed-host. Even at 1000 cd/m(2), the efficiencies still reach 34.2 cd/A and 23.3 lm/W and the driving voltage is only 4.6 V, which is comparable to those reported from the state-of-the-art vacuum-evaporation deposited white OLEDs.

  5. High Efficiency Organic Solar Cells: December 16, 2009 - February 2, 2011

    Energy Technology Data Exchange (ETDEWEB)

    Walker, K.; Joslin, S.

    2011-05-01

    Details on the development of novel organic solar cells incorporating Trimetasphere based acceptors are presented including: baseline performance for Lu-PCBEH acceptor blended with P3HT demonstrated at 4.89% PCE exceeding the 4.5% PCE goal; an increase of over 250mV in Voc was demonstrated for Lu-PCBEH blended with low band gap polymers compared to a comparable C60-PCBM device. The actual Voc was certified at 260mV higher for a low band gap polymer device using the Lu-PCBEH acceptor; and the majority of the effort was focused on development of a device with over 7% PCE. While low current and fill factors suppressed overall device performance for the low band gap polymers tested, significant discoveries were made that point the way for future development of these novel acceptor materials.

  6. Highly Efficient p-i-n Type Organic Light-emitting Diodes Using ...

    African Journals Online (AJOL)

    Both predominantly hole transporting material (TCTA) and an exclusively electron transporting host material (TAZ) are doped with the green phosphorescent dye tris(phenylpyridine)iridium [Ir(ppy)3]. The intrinsic and doped transport and emission layers are formed using a high vacuum controlled co-evaporation deposition ...

  7. Highly Efficient Organic UV Photodetectors Based on Polyfluorene and Naphthalenediimide Blends: Effect of Thermal Annealing

    Directory of Open Access Journals (Sweden)

    Gorkem Memisoglu

    2012-01-01

    Full Text Available A solution-processed organic ultraviolet photodetector (UV-PD is introduced. The active layer of the UV-PD consists of poly(9,9-dioctyl fluorenyl-2,7–yleneethynylene (PFE and N,N′-bis-n-butyl-1,4,5,8- naphthalenediimide (BNDI with a weight ratio of 3 : 1 in chloroform. The effect of thermal annealing on the device properties was investigated from room temperature to 80∘C. The full device structure of ITO/PEDOT:PSS/PFE:BNDI (3 : 1/Al gave responsivity of 410 mA/W at −4 V under 1 mW/cm2 UV light at 368 nm when 60∘C of annealing temperature was used during its preparation. The devices that were annealed over the crystallization temperature of PFE showed a charge transfer resistance increase and a mobility decrease.

  8. Highly efficient fully flexible indium tin oxide free organic light emitting diodes fabricated directly on barrier-foil

    International Nuclear Information System (INIS)

    Bocksrocker, Tobias; Hülsmann, Neele; Eschenbaum, Carsten; Pargner, Andreas; Höfle, Stefan; Maier-Flaig, Florian; Lemmer, Uli

    2013-01-01

    We present a simple method for the fabrication of highly conductive and fully flexible metal/polymer hybrid anodes for efficient organic light emitting diodes (OLEDs). By incorporating ultra-thin metal grids into a conductive polymer, we fabricated anodes with very low sheet resistances and high transparency. After optimizing the metallic grid, OLEDs with these hybrid anodes are superior to OLEDs with standard indium tin oxide (ITO) anodes in luminous efficacy by a factor of ∼ 2. Furthermore, the sheet resistance can be reduced by up to an order of magnitude compared to ITO on polyethylene terephthalate (PET). The devices show a very low turn-on voltage and the hybrid anodes do not change the emissive spectra of the OLEDs. In addition, we fabricated the anodes directly on a barrier foil, making the double sided encapsulation of a typically used PET-substrate unnecessary

  9. High-efficiency organic solar cells based on end-functional-group-modified poly(3-hexylthiophene)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Soo; Lee, Ji Hwang [School of Environmental Science and Engineering Polymer Research Institute, Pohang University of Science and Engineering Pohang, 790-784 (Korea); Lee, Youngmin; Park, Jong Hwan; Kim, Jin Kon; Cho, Kilwon [Department of Chemical Engineering Polymer Research Institute, Pohang University of Science and Engineering Pohang, 790-784 (Korea)

    2010-03-26

    Photovoltaic devices of end-functional-group-modified poly 3-(hexylthiophene)/[6,6]-phenyl-C{sub 61} butyric acid methyl ester (P3HT:PCBM) are fabricated with thermal annealing. The surface energies between donor and acceptor were matched by varying the end group, which can be used to control vertical and horizontal phase separation in the active layer, leading mixed nanomorphology with optimized phase separation, low series resistance, and high performance for solar cell devices. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  10. High-efficiency white organic light-emitting devices with a non-doped yellow phosphorescent emissive layer

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Juan; Yu Junsheng, E-mail: jsyu@uestc.edu.cn; Hu Xiao; Hou Menghan; Jiang Yadong

    2012-03-30

    Highly efficient phosphorescent white organic light-emitting devices (PHWOLEDs) with a simple structure of ITO/TAPC (40 nm)/mCP:FIrpic (20 nm, x wt.%)/bis[2-(4-tertbutylphenyl)benzothiazolato-N,C{sup 2} Prime ] iridium (acetylacetonate) (tbt){sub 2}Ir(acac) (y nm)/Bphen (30 nm)/Mg:Ag (200 nm) have been developed, by inserting a thin layer of non-doped yellow phosphorescent (tbt){sub 2}Ir(acac) between doped blue emitting layer (EML) and electron transporting layer. By changing the doping concentration of the blue EML and the thickness of the non-doped yellow EML, a PHWOLED comprised of higher blue doping concentration and thinner yellow EML achieves a high current efficiency of 31.7 cd/A and Commission Internationale de l'Eclairage coordinates of (0.33, 0.41) at a luminance of 3000 cd/m{sup 2} could be observed. - Highlights: Black-Right-Pointing-Pointer We introduce a simplified architecture for phosphorescent white organic light-emitting device. Black-Right-Pointing-Pointer The key concept of device fabrication is combination of doped blue emissive layer (EML) with non-doped ultra-thin yellow EML. Black-Right-Pointing-Pointer Doping concentration of the blue EML and thickness of the yellow EML are sequentially adjusted. Black-Right-Pointing-Pointer High device performance is achieved due to improved charge carrier balance as well as two parallel emission mechanisms in the EMLs.

  11. Efficient fluorescence/phosphorescence white organic light-emitting diodes with ultra high color stability and mild efficiency roll-off

    Science.gov (United States)

    Du, Xiaoyang; Tao, Silu; Huang, Yun; Yang, Xiaoxia; Ding, Xulin; Zhang, Xiaohong

    2015-11-01

    Efficient fluorescence/phosphorescence hybrid white organic light-emitting diodes (OLEDs) with single doped co-host structure have been fabricated. Device using 9-Naphthyl-10 -(4-triphenylamine)anthrancene as the fluorescent dopant and Ir(ppy)3 and Ir(2-phq)3 as the green and orange phosphorescent dopants show the luminous efficiency of 12.4% (17.6 lm/W, 27.5 cd/A) at 1000 cd/m2. Most important to note that the efficiency-brightness roll-off of the device was very mild. With the brightness rising up to 5000 and 10 000 cd/m2, the efficiency could be kept at 11.8% (14.0 lm/W, 26.5 cd/A) and 11.0% (11.8 lm/W, 25.0 cd/A). The Commission Internationale de L'Eclairage (CIE) coordinates and color rending index (CRI) were measured to be (0.45, 0.48) and 65, respectively, and remained the same in a large range of brightness (1000-10 000 cd/m2), which is scarce in the reported white OLEDs. The performance of the device at high luminance (5000 and 10 000 cd/m2) was among the best reported results including fluorescence/phosphorescence hybrid and all-phosphorescent white OLEDs. Moreover, the CRI of the white OLED can be improved to 83 by using a yellow-green emitter (Ir(ppy)2bop) in the device.

  12. Pyridine substituted spirofluorene derivative as an electron transport material for high efficiency in blue organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Soon Ok; Yook, Kyoung Soo; Lee, Jun Yeob, E-mail: leej17@dankook.ac.k

    2010-11-01

    The quantum efficiency of blue fluorescent organic light-emitting diodes was enhanced by 20% using a pyridine substituted spirofluorene-benzofluorene derivative as an electron transport material. 2',7'-Di(pyridin-3-yl)spiro[benzofluorene-7,9'-fluorene] (SPBP) was synthesized and it was used as the electron transport material to block the hole leakage from the emitting layer. The improvement of the quantum efficiency and power efficiency of the blue fluorescent organic light-emitting diodes using the SPBP was investigated.

  13. Microporous metal–organic framework with dual functionalities for highly efficient removal of acetylene from ethylene/acetylene mixtures

    KAUST Repository

    Hu, Tong-Liang

    2015-06-04

    The removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene is a technologically very important, but highly challenging task. Current removal approaches include the partial hydrogenation over a noble metal catalyst and the solvent extraction of cracked olefins, both of which are cost and energy consumptive. Here we report a microporous metal–organic framework in which the suitable pore/cage spaces preferentially take up much more acetylene than ethylene while the functional amine groups on the pore/cage surfaces further enforce their interactions with acetylene molecules, leading to its superior performance for this separation. The single X-ray diffraction studies, temperature dependent gas sorption isotherms, simulated and experimental column breakthrough curves and molecular simulation studies collaboratively support the claim, underlying the potential of this material for the industrial usage of the removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene at room temperature through the cost- and energy-efficient adsorption separation process.

  14. Highly efficient phosphor-converted white organic light-emitting diodes with moderate microcavity and light-recycling filters.

    Science.gov (United States)

    Cho, Sang-Hwan; Oh, Jeong Rok; Park, Hoo Keun; Kim, Hyoung Kun; Lee, Yong-Hee; Lee, Jae-Gab; Do, Young Rag

    2010-01-18

    We demonstrate the combined effects of a microcavity structure and light-recycling filters (LRFs) on the forward electrical efficiency of phosphor-converted white organic light-emitting diodes (pc-WOLEDs). The introduction of a single pair of low- and high-index layers (SiO(2)/TiO(2)) improves the blue emission from blue OLED and the insertion of blue-passing and yellow-reflecting LRFs enhances the forward yellow emission from the YAG:Ce(3+) phosphors layers. The enhancement of the luminous efficacy of the forward white emission is 1.92 times that of a conventional pc-WOLED with color coordinates of (0.34, 0.34) and a correlated color temperature of about 4800 K.

  15. Hierarchically porous silicon–carbon–nitrogen hybrid materials towards highly efficient and selective adsorption of organic dyes

    Science.gov (United States)

    Meng, Lala; Zhang, Xiaofei; Tang, Yusheng; Su, Kehe; Kong, Jie

    2015-01-01

    The hierarchically macro/micro-porous silicon–carbon–nitrogen (Si–C–N) hybrid material was presented with novel functionalities of totally selective and highly efficient adsorption for organic dyes. The hybrid material was conveniently generated by the pyrolysis of commercial polysilazane precursors using polydivinylbenzene microspheres as sacrificial templates. Owing to the Van der Waals force between sp2-hybridized carbon domains and triphenyl structure of dyes, and electrostatic interaction between dyes and Si-C-N matrix, it exhibites high adsorption capacity and good regeneration and recycling ability for the dyes with triphenyl structure, such as methyl blue (MB), acid fuchsin (AF), basic fuchsin and malachite green. The adsorption process is determined by both surface adsorption and intraparticle diffusion. According to the Langmuir model, the adsorption capacity is 1327.7 mg·g−1 and 1084.5 mg·g−1 for MB and AF, respectively, which is much higher than that of many other adsorbents. On the contrary, the hybrid materials do not adsorb the dyes with azo benzene structures, such as methyl orange, methyl red and congro red. Thus, the hierarchically porous Si–C–N hybrid material from a facile and low cost polymer-derived strategy provides a new perspective and possesses a significant potential in the treatment of wastewater with complex organic pollutants. PMID:25604334

  16. Highly Efficient and Stable Organic Solar Cells via Interface Engineering with a Nanostructured ITR-GO/PFN Bilayer Cathode Interlayer

    Directory of Open Access Journals (Sweden)

    Ding Zheng

    2017-08-01

    Full Text Available An innovative bilayer cathode interlayer (CIL with a nanostructure consisting of in situ thermal reduced graphene oxide (ITR-GO and poly[(9,9-bis(3′-(N,N-dimethylamionpropyl-2,7-fluorene-alt-2,7-(9,9-dioctyl fluorene] (PFN has been fabricated for inverted organic solar cells (OSCs. An approach to prepare a CIL of high electronic quality by using ITR-GO as a template to modulate the morphology of the interface between the active layer and electrode and to further reduce the work function of the electrode has also been realized. This bilayer ITR-GO/PFN CIL is processed by a spray-coating method with facile in situ thermal reduction. Meanwhile, the CIL shows a good charge transport efficiency and less charge recombination, which leads to a significant enhancement of the power conversion efficiency from 6.47% to 8.34% for Poly({4,8-bis[(2-ethylhexyloxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexylcarbonyl]thieno[3,4-b]thiophenediyl} (PTB7:[6,6]-phenyl-C71-butyric acid methyl ester (PC71BM-based OSCs. In addition, the long-term stability of the OSC is improved by using the ITR-GO/PFN CIL when compared with the pristine device. These results indicate that the bilayer ITR-GO/PFN CIL is a promising way to realize high-efficiency and stable OSCs by using water-soluble conjugated polymer electrolytes such as PFN.

  17. Study of Sequential Dexter Energy Transfer in High Efficient Phosphorescent White Organic Light-Emitting Diodes with Single Emissive Layer

    Science.gov (United States)

    Kim, Jin Wook; You, Seung Il; Kim, Nam Ho; Yoon, Ju-An; Cheah, Kok Wai; Zhu, Fu Rong; Kim, Woo Young

    2014-11-01

    In this study, we report our effort to realize high performance single emissive layer three color white phosphorescent organic light emitting diodes (PHOLEDs) through sequential Dexter energy transfer of blue, green and red dopants. The PHOLEDs had a structure of; ITO(1500 Å)/NPB(700 Å)/mCP:Firpic-x%:Ir(ppy)3-0.5%:Ir(piq)3-y%(300 Å)/TPBi(300 Å)/Liq(20 Å)/Al(1200 Å). The dopant concentrations of FIrpic, Ir(ppy)3 and Ir(piq)3 were adjusted and optimized to facilitate the preferred energy transfer processes attaining both the best luminous efficiency and CIE color coordinates. The presence of a deep trapping center for charge carriers in the emissive layer was confirmed by the observed red shift in electroluminescent spectra. White PHOLEDs, with phosphorescent dopant concentrations of FIrpic-8.0%:Ir(ppy)3-0.5%:Ir(piq)3-0.5% in the mCP host of the single emissive layer, had a maximum luminescence of 37,810 cd/m2 at 11 V and a luminous efficiency of 48.10 cd/A at 5 V with CIE color coordinates of (0.35, 0.41).

  18. Efficiency measures for industrial organization

    NARCIS (Netherlands)

    ten Raa, Thijs; Ray, Subhash C.; Kumbhakar, Subal C.; Dua, Pami

    2015-01-01

    The aim of the paper is to measure the efficiency of an industry, and to decompose it in firm efficiencies—which indicate how close firms approximate best practices—and an organization efficiency—which indicates the degree of optimality of the number of firms and their distribution. The latter

  19. Detection of Simian Immunodeficiency Virus in Semen, Urethra, and Male Reproductive Organs during Efficient Highly Active Antiretroviral Therapy

    Science.gov (United States)

    Matusali, G.; Dereuddre-Bosquet, N.; Le Tortorec, A.; Moreau, M.; Satie, A.-P.; Mahé, D.; Roumaud, P.; Bourry, O.; Sylla, N.; Bernard-Stoecklin, S.; Pruvost, A.; Le Grand, R.

    2015-01-01

    ABSTRACT A number of men receiving prolonged suppressive highly active antiretroviral therapy (HAART) still shed human immunodeficiency virus (HIV) in semen. To investigate whether this seminal shedding may be due to poor drug penetration and/or viral production by long-lived cells within male genital tissues, we analyzed semen and reproductive tissues from macaques chronically infected with simian immunodeficiency virus mac251 (SIVmac251) who were treated for 4 months with HAART, which was intensified over the last 7 weeks with an integrase inhibitor. We showed that a subset of treated animals continued shedding SIV in semen despite efficient HAART. This shedding was not associated with low antiretroviral drug concentrations in semen or in testis, epididymis, seminal vesicles, and prostate. HAART had no significant impact on SIV RNA in the urethra, whereas it drastically reduced SIV RNA levels in the prostate and vas deferens and to a lesser extent in the epididymis and seminal vesicle. The only detectable SIV RNA-positive cells within the male genital tract after HAART were urethral macrophages. SIV DNA levels in genital tissues were not decreased by HAART, suggesting the presence throughout the male genital tract of nonproductively infected cells. In conclusion, our results demonstrate that 4 months of HAART induced variable and limited control of viral infection in the male reproductive organs, particularly in the urethra, and suggest that infected long-lived cells in the male genital tract may be involved in persistent seminal shedding during HAART. These results pave the way for further investigations of male genital organ infection in long-term-treated infected individuals. IMPORTANCE A substantial subset of men receiving prolonged HAART suppressing viral loads in the blood still harbor HIV in semen, and cases of sexual transmission have been reported. To understand the origin of this persistence, we analyzed the semen and male reproductive tissues from SIV

  20. Flexible organic tandem solar modules with 6% efficiency: combining roll-to-roll compatible processing with high geometric fill factors

    DEFF Research Database (Denmark)

    Spyropoulos, G. D.; Kubis, P.; Li, Na

    2014-01-01

    Organic solar cell technology bears the potential for high photovoltaic performance combined with truly low-cost, high-volume processing. Here we demonstrate organic tandem solar modules on flexible substrates fabricated by fully roll-to-roll compatible processing at temperatures...

  1. S,N-Heteroacene-Based Copolymers for Highly Efficient Organic Field Effect Transistors and Organic Solar Cells: Critical Impact of Aromatic Subunits in the Ladder π-System.

    Science.gov (United States)

    Chung, Chin-Lung; Chen, Hsieh-Chih; Yang, Yun-Siou; Tung, Wei-Yao; Chen, Jian-Wei; Chen, Wen-Chang; Wu, Chun-Guey; Wong, Ken-Tsung

    2018-02-21

    Three novel donor-acceptor alternating polymers containing ladder-type pentacyclic heteroacenes (PBo, PBi, and PT) are synthesized, characterized, and further applied to organic field effect transistors (OFETs) and polymer solar cells. Significant aspects of quinoidal characters, electrochemical properties, optical absorption, frontier orbitals, backbone coplanarity, molecular orientation, charge carrier mobilities, morphology discrepancies, and the corresponding device performances are notably different with various heteroarenes. PT exhibits a stronger quinoidal mesomeric structure, linear and coplanar conformation, smooth surface morphology, and better bimodal crystalline structures, which is beneficial to extend the π-conjugation and promotes charge transport via 3-D transport pathways and in consequence improves overall device performances. Organic photovoltaics based on the PT polymer achieve a power conversion efficiency of 6.04% along with a high short-circuit current density (J SC ) of 14.68 mA cm -2 , and a high hole mobility of 0.1 cm 2 V -1 s -1 is fulfilled in an OFET, which is superior to those of its counterparts, PBi and PBo.

  2. Hybrid Organic-Inorganic Perovskites Open a New Era for Low-Cost, High Efficiency Solar Cells

    Directory of Open Access Journals (Sweden)

    Guiming Peng

    2015-01-01

    Full Text Available The ramping solar energy to electricity conversion efficiencies of hybrid organic-inorganic perovskite solar cells during the last five years have opened new doors to low-cost solar energy. The record power conversion efficiency has climbed to 19.3% in August 2014 and then jumped to 20.1% in November. In this review, the main achievements for perovskite solar cells categorized from a viewpoint of device structure are overviewed. The challenges and prospects for future development of this field are also briefly presented.

  3. Electrochemical catalytic reforming of oxygenated-organic compounds: a highly efficient method for production of hydrogen from bio-oil.

    Science.gov (United States)

    Yuan, Lixia; Chen, Yaqiong; Song, Chongfu; Ye, Tongqi; Guo, Qingxiang; Zhu, Qingshi; Torimoto, Youshifumi; Li, Quanxin

    2008-11-07

    A novel approach to produce hydrogen from bio-oil was obtained with high carbon conversion (>90%) and hydrogen yield (>90%) at Tcatalytic reforming of oxygenated-organic compounds over 18%NiO/Al(2)O(3) reforming catalyst; thermal electrons play important promoting roles in the decomposition and reforming of the oxygenated-organic compounds in the bio-oil.

  4. Design of efficient molecular organic light-emitting diodes by a high-throughput virtual screening and experimental approach

    Science.gov (United States)

    Gómez-Bombarelli, Rafael; Aguilera-Iparraguirre, Jorge; Hirzel, Timothy D.; Duvenaud, David; MacLaurin, Dougal; Blood-Forsythe, Martin A.; Chae, Hyun Sik; Einzinger, Markus; Ha, Dong-Gwang; Wu, Tony; Markopoulos, Georgios; Jeon, Soonok; Kang, Hosuk; Miyazaki, Hiroshi; Numata, Masaki; Kim, Sunghan; Huang, Wenliang; Hong, Seong Ik; Baldo, Marc; Adams, Ryan P.; Aspuru-Guzik, Alán

    2016-10-01

    Virtual screening is becoming a ground-breaking tool for molecular discovery due to the exponential growth of available computer time and constant improvement of simulation and machine learning techniques. We report an integrated organic functional material design process that incorporates theoretical insight, quantum chemistry, cheminformatics, machine learning, industrial expertise, organic synthesis, molecular characterization, device fabrication and optoelectronic testing. After exploring a search space of 1.6 million molecules and screening over 400,000 of them using time-dependent density functional theory, we identified thousands of promising novel organic light-emitting diode molecules across the visible spectrum. Our team collaboratively selected the best candidates from this set. The experimentally determined external quantum efficiencies for these synthesized candidates were as large as 22%.

  5. Highly efficient organic solar Cells based on a robust room-temperature solution-processed copper iodide hole transporter

    KAUST Repository

    Zhao, Kui

    2015-07-30

    Achieving high performance and reliable organic solar cells hinges on the development of stable and energetically suitable hole transporting buffer layers in tune with the electrode and photoactive materials of the solar cell stack. Here we have identified solution-processed copper(I) iodide (CuI) thin films with low-temperature processing conditions as an effective hole–transporting layer (HTL) for a wide range of polymer:fullerene bulk heterojunction (BHJ) systems. The solar cells using CuI HTL show higher power conversion efficiency (PCE) in standard device structure for polymer blends, up to PCE of 8.8%, as compared with poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, for a broad range of polymer:fullerene systems. The CuI layer properties and solar cell device behavior are shown to be remarkably robust and insensitive to a wide range of processing conditions of the HTL, including processing solvent, annealing temperature (room temperature up to 200 °C), and film thickness. CuI is also shown to improve the overall lifetime of solar cells in the standard architecture as compared to PEDOT:PSS. We further demonstrate promising solar cell performance when using CuI as top HTL in an inverted device architecture. The observation of uncommon properties, such as photoconductivity of CuI and templating effects on the BHJ layer formation, are also discussed. This study points to CuI as being a good candidate to replace PEDOT:PSS in solution-processed solar cells thanks to the facile implementation and demonstrated robustness of CuI thin films.

  6. Highly efficient organic solar Cells based on a robust room-temperature solution-processed copper iodide hole transporter

    KAUST Repository

    Zhao, Kui; Ngongang Ndjawa, Guy Olivier; Jagadamma, Lethy Krishnan; El Labban, Abdulrahman; Hu, Hanlin; Wang, Qingxiao; Li, Ruipeng; Abdelsamie, Maged; Beaujuge, Pierre; Amassian, Aram

    2015-01-01

    Achieving high performance and reliable organic solar cells hinges on the development of stable and energetically suitable hole transporting buffer layers in tune with the electrode and photoactive materials of the solar cell stack. Here we have identified solution-processed copper(I) iodide (CuI) thin films with low-temperature processing conditions as an effective hole–transporting layer (HTL) for a wide range of polymer:fullerene bulk heterojunction (BHJ) systems. The solar cells using CuI HTL show higher power conversion efficiency (PCE) in standard device structure for polymer blends, up to PCE of 8.8%, as compared with poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, for a broad range of polymer:fullerene systems. The CuI layer properties and solar cell device behavior are shown to be remarkably robust and insensitive to a wide range of processing conditions of the HTL, including processing solvent, annealing temperature (room temperature up to 200 °C), and film thickness. CuI is also shown to improve the overall lifetime of solar cells in the standard architecture as compared to PEDOT:PSS. We further demonstrate promising solar cell performance when using CuI as top HTL in an inverted device architecture. The observation of uncommon properties, such as photoconductivity of CuI and templating effects on the BHJ layer formation, are also discussed. This study points to CuI as being a good candidate to replace PEDOT:PSS in solution-processed solar cells thanks to the facile implementation and demonstrated robustness of CuI thin films.

  7. An Unfused-Core-Based Nonfullerene Acceptor Enables High-Efficiency Organic Solar Cells with Excellent Morphological Stability at High Temperatures.

    Science.gov (United States)

    Li, Shuixing; Zhan, Lingling; Liu, Feng; Ren, Jie; Shi, Minmin; Li, Chang-Zhi; Russell, Thomas P; Chen, Hongzheng

    2018-02-01

    Most nonfullerene acceptors developed so far for high-performance organic solar cells (OSCs) are designed in planar molecular geometry containing a fused-ring core. In this work, a new nonfullerene acceptor of DF-PCIC is synthesized with an unfused-ring core containing two cyclopentadithiophene (CPDT) moieties and one 2,5-difluorobenzene (DFB) group. A nearly planar geometry is realized through the F···H noncovalent interaction between CPDT and DFB for DF-PCIC. After proper optimizations, the OSCs with DF-PCIC as the acceptor and the polymer PBDB-T as the donor yield the best power conversion efficiency (PCE) of 10.14% with a high fill factor of 0.72. To the best of our knowledge, this efficiency is among the highest values for the OSCs with nonfullerene acceptors owning unfused-ring cores. Furthermore, no obvious morphological changes are observed for the thermally treated PBDB-T:DF-PCIC blended films, and the relevant devices can keep ≈70% of the original PCEs upon thermal treatment at 180 °C for 12 h. This tolerance of such a high temperature for so long time is rarely reported for fullerene-free OSCs, which might be due to the unique unfused-ring core of DF-PCIC. Therefore, the work provides new idea for the design of new nonfullerene acceptors applicable in commercial OSCs in the future. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Highly efficient and simplified phosphorescence white organic light-emitting diodes based on synthesized deep-blue host and orange emitter

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Ja Ryong; Lee, Seok Jae; Hyung, Gun Woo; Kim, Bo Young; Lee, Dong Hyung [Department of Information Display, Hongik University, Seoul 121-791 (Korea, Republic of); Kim, Woo Young [Department of Green Energy and Semiconductor Engineering, Hoseo University, Asan 336-795 (Korea, Republic of); Lee, Kum Hee [Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Yoon, Seung Soo, E-mail: ssyoon@skku.edu [Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Young Kwan, E-mail: kimyk@hongik.ac.kr [Department of Information Display, Hongik University, Seoul 121-791 (Korea, Republic of)

    2013-10-01

    The authors have demonstrated a highly efficient and stable phosphorescent white organic light-emitting diode (WOLED), which has been achieved by doping only one orange phosphorescent emitter, Bis(5-benzoyl-2-(4-fluorophenyl)pyridinato-C,N)iridium(III) acetylacetonate into an appropriate deep blue phosphorescent host, 4,4'-bis(4-(triphenylsilyl)phenyl)-1,1'-binaphthyl as an emitting layer (EML). The WOLED has been achieved by effective confinement of triplet excitons to emit a warm white color. The optimized WOLED, with a simple structure as a hole transporting layer-EML-electron transporting layer, showed a maximum luminous efficiency of 22.38 cd/A, a maximum power efficiency of 12.01 lm/W, a maximum external quantum efficiency of 7.32%, and CIEx,y coordinates of (0.38,0.42) at 500 cd/m{sup 2}, respectively. - Highlights: • Highly efficient phosphorescent white organic light-emitting diode (WOLED) • Single emitting layer consists of synthesized deep blue host and orange emitter • The WOLED with high EL efficiencies due to efficient triplet exciton confinement.

  9. Highly efficient high temperature electrolysis

    DEFF Research Database (Denmark)

    Hauch, Anne; Ebbesen, Sune; Jensen, Søren Højgaard

    2008-01-01

    High temperature electrolysis of water and steam may provide an efficient, cost effective and environmentally friendly production of H-2 Using electricity produced from sustainable, non-fossil energy sources. To achieve cost competitive electrolysis cells that are both high performing i.e. minimum...... internal resistance of the cell, and long-term stable, it is critical to develop electrode materials that are optimal for steam electrolysis. In this article electrolysis cells for electrolysis of water or steam at temperatures above 200 degrees C for production of H-2 are reviewed. High temperature...... electrolysis is favourable from a thermodynamic point of view, because a part of the required energy can be supplied as thermal heat, and the activation barrier is lowered increasing the H-2 production rate. Only two types of cells operating at high temperature (above 200 degrees C) have been described...

  10. Design principle for efficient charge separation at the donor-acceptor interface for high performance organic solar cell device

    Science.gov (United States)

    Nie, Wanyi; Gupta, Gautam; Crone, Brian; Wang, Hsing-Lin; Mohite, Aditya; MPA-11 Material synthesis and integrated device Team; MPA-chemistry Team

    2014-03-01

    The performance of donor (D) /acceptor (A) structure based organic electronic devices, such as solar cell, light emitting devices etc., relays on the charge transfer process at the interface dramatically. In organic solar cell, the photo-induced electron-hole pair is tightly bonded and will form a charge transfer (CT) state at the D/A interface after dissociation. There is a large chance for them to recombine through CT state and thus is a major loss that limit the overall performance. Here, we report three different strategies that allow us to completely suppress the exciplex (or charge transfer state) recombination between any D/A system. We observe that the photocurrent increases by 300% and the power conversion efficiency increases by 4-5 times simply by inserting a spacer layer in the form of an a) insulator b) Oliogomer or using a c) heavy atom at the donor-acceptor interface in a P3HT/C60 bilayer device. By using those different functional mono layers, we successfully suppressed the exciplex recombination in evidence of increased photocurrent and open circuit voltage. Moreover, these strategies are applicable universally to any donor-acceptor interface. And we demonstrated such strategies in a bulk-heterojunction device which improved the power conversion efficiency from 3.5% up to 4.6%.

  11. High efficiency rubrene based inverted top-emission organic light emitting devices with a mixed single layer

    International Nuclear Information System (INIS)

    Wang, Zhaokui; Lou, Yanhui; Naka, Shigeki; Okada, Hiroyuki

    2010-01-01

    Inverted top-emission organic light emitting devices (TEOLEDs) with a mixed single layer by mixing of electron transport materials (PyPySPyPy and Alq 3 ), hole transport material (α-NPD) and dope material (rubrene) were investigated. Maximum power efficiency of 3.5 lm/W and maximum luminance of 7000 cd/m 2 were obtained by optimizing the mixing ratio of PyPySPyPy:Alq 3 :α-NPD:rubrene=25:50:25:1. Luminance and power efficiency of mixed single layer device were two times improved compared to bi-layer heterojunction device and tri-layer heterojunction device. Lifetime test also shows that the mixed single layer device exhibits longer operational lifetimes of 343 h, which is three times longer than the 109 h for tri-layer device, and two times longer than the 158 h for bi-layer device. In addition, the maximum luminance and power efficiency were obtained at 20,000 cd/m 2 and 7.5 lm/W, respectively, when a TPD layer of 45 nm was capped onto the top metal electrode.

  12. Highly efficient and stable white organic light emitting diode base on double recombination zones of phosphorescent blue/orange emitters.

    Science.gov (United States)

    Lee, Seok Jae; Koo, Ja Ryong; Lim, Dong Hwan; Park, Hye Rim; Kim, Young Kwan; Ha, Yunkyoung

    2011-08-01

    We demonstrated efficient and stable white phosphorescent organic light-emitting diodes (OLEDs) with double-emitting layers (D-EMLs), which were comprised of two emissive layers with a hole transport-type host of N,N'-dicarbazolyl-3,5-benzene (mCP) and a electron transport-type host of 2,2',2"-(1,3,5-benzenetryl)tris(1-phenyl)-1H-benzimidazol (TPBi) with blue/orange emitters, respectively. We fabricated two type white devices with single emitting layer (S-EML) and D-EML of orange emitter, maintaining double recombination zone of blue emitter. In addition, the device architecture was developed to confine excitons inside the D-EMLs and to manage triplet excitons by controlling the charge injection. As a result, light-emitting performances of white OLED with D-EMLs were improved and showed the steady CIE coordinates compared to that with S-EML of orange emitter, which demonstrated the maximum luminous efficiency and external quantum efficiency were 21.38 cd/A and 11.09%. It also showed the stable white emission with CIE(x,y) coordinates from (x = 0.36, y = 0.37) at 6 V to (x = 0.33, y = 0.38) at 12 V.

  13. HIGH EFFICIENCY TURBINE

    OpenAIRE

    VARMA, VIJAYA KRUSHNA

    2012-01-01

    Varma designed ultra modern and high efficiency turbines which can use gas, steam or fuels as feed to produce electricity or mechanical work for wide range of usages and applications in industries or at work sites. Varma turbine engines can be used in all types of vehicles. These turbines can also be used in aircraft, ships, battle tanks, dredgers, mining equipment, earth moving machines etc, Salient features of Varma Turbines. 1. Varma turbines are simple in design, easy to manufac...

  14. HOLE-BLOCKING LAYERS FOR SILICON/ORGANIC HETEROJUNCTIONS: A NEW CLASS OF HIGH-EFFICIENCY LOW-COST PV

    Energy Technology Data Exchange (ETDEWEB)

    Sturm, James [Princeton Univ., NJ (United States)

    2017-12-04

    This project is the first investigation of the use of thin titanium dioxide layers on silicon as a hole-blocking / electron-transparent selective contact to silicon. The work was motivated by the goal of a high-efficiency low-cost silicon-based solar cells that could be processed entirely at low temperature (300 Degree Celsius) or less, without requiring plasma-processing.

  15. Interface and thickness tuning for blade coated small-molecule organic light-emitting diodes with high power efficiency

    Science.gov (United States)

    Chang, Yu-Fan; Chiu, Yu-Chian; Chang, Hao-Wen; Wang, Yi-Siang; Shih, Yi-Lun; Wu, Chih-Hao; Liu, Yi-Lun; Lin, Yu-Sheng; Meng, Hsin-Fei; Chi, Yun; Huang, Heh-Lung; Tseng, Mei-Rurng; Lin, Hao-Wu; Zan, Hsiao-Wen; Horng, Sheng-Fu; Juang, Jenh-Yih

    2013-09-01

    We developed a general method based on fluorescence microscopy to characterize the interface dissolution in multi-layer organic light-emitting diodes (OLEDs) by blade coating. A sharp bi-layer edge was created before blade coating, with the bottom layer being insoluble and top layer soluble. After blade coating, fluorescence images showed that the edge of the top layer shifted when the layer dissolved completely, whereas the bottom layer's edge remained in place as a positioning mark. The dissolution depth was determined to be 15-20 nm when the emissive-layer host of 2,6-bis (3-(9H-carbazol-9-yl)phenyl) pyridine (26DCzPPy) was coated on the hole-transport layer of N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine(NPB), which was consistent with a sudden drop in efficiency of orange OLEDs with layer thickness below 20 nm. Thus, the layer thickness of OLEDs was optimized to stay more than 20 nm for blade coating. For a two-color white OLED with the structure TCTA/26DCzPPy:PO-01-TB:FIrpic/TPBI, efficiency was 24 cd/A and 8.5 lm/W at 1000 cd/m2. For a three-color white OLED with Os(fptz)2(dhpm) added as the emitter, the efficiency was 12.3 cd/A and 3.7 lm/W at 1000 cd/m2. For a green device with the structure TCTA/26DCzPPy:Ir(mppy)3/TPBI, the efficiency was 41.9 cd/A and 23.4 lm/W at 1000 cd/m2.

  16. Highly efficient blue organic light emitting device using indium-free transparent anode Ga:ZnO with scalability for large area coating

    International Nuclear Information System (INIS)

    Wang Liang; Matson, Dean W.; Polikarpov, Evgueni; Swensen, James S.; Bonham, Charles C.; Cosimbescu, Lelia; Gaspar, Daniel J.; Padmaperuma, Asanga B.; Berry, Joseph J.; Ginley, David S.

    2010-01-01

    Organic light emitting devices have been achieved with an indium-free transparent anode, Ga doped ZnO (GZO). A large area coating technique was used (RF magnetron sputtering) to deposit the GZO films onto glass. The respective organic light emitting devices exhibited an operational voltage of 3.7 V, an external quantum efficiency of 17%, and a power efficiency of 39 lm/W at a current density of 1 mA/cm 2 . These parameters are well within acceptable standards for blue OLEDs to generate a white light with high enough brightness for general lighting applications. It is expected that high-efficiency, long-lifetime, large area, and cost-effective white OLEDs can be made with these indium-free anode materials.

  17. High-efficiency green phosphorescent organic light-emitting diodes with double-emission layer and thick N-doped electron transport layer

    Energy Technology Data Exchange (ETDEWEB)

    Nobuki, Shunichiro, E-mail: shunichiro.nobuki.nb@hitachi.com [Hitachi Research Laboratory, Hitachi Ltd., 7-1-1 Omika-cho, Hitachi-city, Ibaraki 319-1292 (Japan); Wakana, Hironori; Ishihara, Shingo [Hitachi Research Laboratory, Hitachi Ltd., 7-1-1 Omika-cho, Hitachi-city, Ibaraki 319-1292 (Japan); Mikami, Akiyoshi [Dept. of Electrical Engineering, Kanazawa Institute of Technology, 7-1 Ohgigaoka, Nonoichimachi, Ishikawa 921-8501 (Japan)

    2014-03-03

    We have developed green phosphorescent organic light-emitting diodes (OLEDs) with high external quantum efficiency of 59.7% and power efficiency of 243 lm/W at 2.73 V at 0.053 mA/cm{sup 2}. A double emission layer and a thick n-doped electron transport layer were adopted to improve the exciton recombination factor. A high refractive index hemispherical lens was attached to a high refractive index substrate for extracting light trapped inside the substrate and the multiple-layers of OLEDs to air. Additionally, we analyzed an energy loss mechanism to clarify room for the improvement of our OLEDs including the charge balance factor. - Highlights: • We developed high efficiency green phosphorescent organic light-emitting diode (OLED). • Our OLED had external quantum efficiency of 59.7% and power efficiency of 243 lm/W. • A double emission layer and thick n-doped electron transport layer were adopted. • High refractive index media (hemispherical lens and substrate) were also used. • We analyzed an energy loss mechanism to clarify the charge balance factor of our OLED.

  18. Highly efficient inverted organic light emitting diodes by inserting a zinc oxide/polyethyleneimine (ZnO:PEI) nano-composite interfacial layer

    Science.gov (United States)

    Kaçar, Rifat; Pıravadılı Mucur, Selin; Yıldız, Fikret; Dabak, Salih; Tekin, Emine

    2017-06-01

    The electrode/organic interface is one of the key factors in attaining superior device performance in organic electronics, and inserting a tailor-made layer can dramatically modify its properties. The use of nano-composite (NC) materials leads to many advantages by combining materials with the objective of obtaining a desirable combination of properties. In this context, zinc oxide/polyethyleneimine (ZnO:PEI) NC film was incorporated as an interfacial layer into inverted bottom-emission organic light emitting diodes (IBOLEDs) and fully optimized. For orange-red emissive MEH-PPV based IBOLEDs, a high power efficiency of 6.1 lm W-1 at a luminance of 1000 cd m-2 has been achieved. Notably, the external quantum efficiency (EQE) increased from 0.1 to 4.8% and the current efficiency (CE) increased from 0.2 to 8.7 cd A-1 with rise in luminance (L) from 1000 to above 10 000 cd m-2 levels when compared to that of pristine ZnO-based devices. An identical device architecture containing a ZnO:PEI NC layer has also been used to successfully fabricate green and blue emissive IBOLEDs. The significant enhancement in the inverted device performance, in terms of luminance and efficiency, is attributed to a good energy-level alignment between the cathode/organic interface which leads to effective carrier balance, resulting in efficient radiative-recombination.

  19. Low-cost electrochemical treatment of indium tin oxide anodes for high-efficiency organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Hui Cheng, Chuan, E-mail: chengchuanhui@dlut.edu.cn; Shan Liang, Ze; Gang Wang, Li; Dong Gao, Guo; Zhou, Ting; Ming Bian, Ji; Min Luo, Ying [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Tong Du, Guo, E-mail: dugt@dlut.edu.cn [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

    2014-01-27

    We demonstrate a simple low-cost approach as an alternative to conventional O{sub 2} plasma treatment to modify the surface of indium tin oxide (ITO) anodes for use in organic light-emitting diodes. ITO is functionalized with F{sup −} ions by electrochemical treatment in dilute hydrofluoric acid. An electrode with a work function of 5.2 eV is achieved following fluorination. Using this electrode, a maximum external quantum efficiency of 26.0% (91 cd/A, 102 lm/W) is obtained, which is 12% higher than that of a device using the O{sub 2} plasma-treated ITO. Fluorination also increases the transparency in the near-infrared region.

  20. Highly Efficient Cooperative Catalysis by Co III (Porphyrin) Pairs in Interpenetrating Metal-Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Zekai; Zhang, Zhi-Ming; Chen, Yu-Sheng; Lin, Wenbin (UC); (Xiamen)

    2016-12-02

    A series of porous twofold interpenetrated In-CoIII(porphyrin) metal–organic frameworks (MOFs) were constructed by in situ metalation of porphyrin bridging ligands and used as efficient cooperative catalysts for the hydration of terminal alkynes. The twofold interpenetrating structure brings adjacent CoIII(porphyrins) in the two networks parallel to each other with a distance of about 8.8 Å, an ideal distance for the simultaneous activation of both substrates in alkyne hydration reactions. As a result, the In-CoIII(porphyrin) MOFs exhibit much higher (up to 38 times) catalytic activity than either homogeneous catalysts or MOF controls with isolated CoIII(porphyrin) centers, thus highlighting the potential application of MOFs in cooperative catalysis.

  1. Suppression of external quantum efficiency roll-off of nanopatterned organic-light emitting diodes at high current densities

    Energy Technology Data Exchange (ETDEWEB)

    Kuwae, Hiroyuki; Kasahara, Takashi [Nano-Science and Nano-Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); JST, ERATO, Adachi Molecular Exciton Engineering Project, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Nitta, Atsushi; Yoshida, Kou; Inoue, Munetomo [Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Matsushima, Toshinori; Adachi, Chihaya, E-mail: adachi@cstf.kyushu-u.ac.jp [JST, ERATO, Adachi Molecular Exciton Engineering Project, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Shoji, Shuichi [Nano-Science and Nano-Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); Mizuno, Jun [JST, ERATO, Adachi Molecular Exciton Engineering Project, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Research Organization for Nano and Life Innovation, Waseda University, 513 Waseda Tsurumaki-cho, Shinjuku, Tokyo 162-0041 (Japan)

    2015-10-21

    We developed organic light-emitting diodes (OLEDs) with nanopatterned current flow regions using electron-beam lithography with the aim of suppressing singlet–polaron annihilation (SPA). Nanopatterns composed of lines and circles were used in the current flow regions of nano-line and nano-dot OLEDs, respectively. Excitons partially escape from the current flow regions where SPA takes place. As such, current densities where external quantum efficiencies were half of their initial values (J{sub 0}) increased as line width and circle diameter were decreased to close to the exciton diffusion length. Circles were more efficient at enhancing exciton escape and increasing J{sub 0} than lines. The J{sub 0} increase in the nano-dot OLEDs containing nanopatterned circles with a diameter of 50 nm was approximately 41-fold that of a conventional OLED with a current flow region of 4 mm{sup 2}. The dependence of J{sub 0} on the size and shape of the nanopatterns was well explained by an SPA model that considered exciton diffusion. Nanopatterning of OLEDs is a feasible method of obtaining large J{sub 0}.

  2. A quantum-chemical perspective into low optical-gap polymers for highly-efficient organic solar cells

    KAUST Repository

    Risko, Chad

    2011-03-15

    The recent and rapid enhancement in power conversion efficiencies of organic-based, bulk heterojunction solar cells has been a consequence of both improved materials design and better understanding of the underlying physical processes involved in photocurrent generation. In this Perspective, we first present an overview of the application of quantum-chemical techniques to study the intrinsic material properties and molecular- and nano-scale processes involved in device operation. In the second part, these quantum-chemical tools are applied to an oligomer-based study on a collection of donor-acceptor copolymers that have been used in the highest-efficiency solar cell devices reported to date. The quantum-chemical results are found to be in good agreement with the empirical data related to the electronic and optical properties. In particular, they provide insight into the natures of the electronic excitations responsible for the near-infrared/visible absorption profiles, as well as into the energetics of the low-lying singlet and triplet states. These results lead to a better understanding of the inherent differences among the materials, and highlight the usefulness of quantum chemistry as an instrument for material design. Importantly, the results also point to the need to continue the development of integrated, multi scale modeling approaches to provide a thorough understanding of the materials properties. © The Royal Society of Chemistry 2011.

  3. Flexible 3D Fe@VO2 core-shell mesh: A highly efficient and easy-recycling catalyst for the removal of organic dyes.

    Science.gov (United States)

    Li, Jing; Wang, Ruoqi; Su, Zhen; Zhang, Dandan; Li, Heping; Yan, Youwei

    2018-10-01

    Nowadays, it is extremely urgent to search for efficient and effective catalysts for water purification due to the severe worldwide water-contamination crises. Here, 3D Fe@VO 2 core-shell mesh, a highly efficient catalyst toward removal of organic dyes with excellent recycling ability in the dark is designed and developed for the first time. This novel core-shell structure is actually 304 stainless steel mesh coated by VO 2 , fabricated by an electrophoretic deposition method. In such a core-shell structure, Fe as the core allows much easier separation from the water, endowing the catalyst with a flexible property for easy recycling, while VO 2 as the shell is highly efficient in degradation of organic dyes with the addition of H 2 O 2 . More intriguingly, the 3D Fe@VO 2 core-shell mesh exhibits favorable performance across a wide pH range. The 3D Fe@VO 2 core-shell mesh can decompose organic dyes both in a light-free condition and under visible irradiation. The possible catalytic oxidation mechanism of Fe@VO 2 /H 2 O 2 system is also proposed in this work. Considering its facile fabrication, remarkable catalytic efficiency across a wide pH range, and easy recycling characteristic, the 3D Fe@VO 2 core-shell mesh is a newly developed high-performance catalyst for addressing the universal water crises. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Control of indium tin oxide anode work function modified using Langmuir-Blodgett monolayer for high-efficiency organic photovoltaics

    Directory of Open Access Journals (Sweden)

    Yuya Yokokura

    2017-08-01

    Full Text Available The use of Langmuir-Blodgett (LB monolayers to modify the indium tin oxide (ITO work function and thus improve the performance of zinc phthalocyanine (ZnPc/fullerene (C60-based and boron subphthalocyanine chloride (SubPc/C60-based small molecule organic photovoltaic devices (OPVs was examined. In general, LB precursor compounds contain one or more long alkyl chain substituents that can act as spacers to prevent electrical contact with adjoining electrode surfaces. As one example of such a compound, arachidic acid (CH3(CH218COOH was inserted in the forms of one-layer, three-layer or five-layer LB films between the anode ITO layer and the p-type layer in ZnPc-C60-based OPVs to investigate the effects of the long alkyl chain group when it acts as an electrically insulating spacer. The short-circuit current density (Jsc values of the OPVs with the three- and five-layer inserts (1.78 mA·cm−2 and 0.61 mA·cm−2, respectively were reduced dramatically, whereas the Jsc value for the OPV with the single-layer insertion (2.88 mA·cm−2 was comparable to that of the OPV without any insert (3.14 mA·cm-2. The ITO work function was shifted positively by LB deposition of a surfactant compound, C9F19C2H4-O-C2H4-COOH (PFECA, which contained a fluorinated head group. This positive effect was maintained even after formation of an upper p-type organic layer. The Jsc and open-circuit voltage (Voc of the SubPc-C60-based OPV with the LB-modified ITO layers were effectively enhanced. As a result, a 42% increase in device efficiency was achieved.

  5. High-efficiency CARM

    Energy Technology Data Exchange (ETDEWEB)

    Bratman, V.L.; Kol`chugin, B.D.; Samsonov, S.V.; Volkov, A.B. [Institute of Applied Physics, Nizhny Novgorod (Russian Federation)

    1995-12-31

    The Cyclotron Autoresonance Maser (CARM) is a well-known variety of FEMs. Unlike the ubitron in which electrons move in a periodical undulator field, in the CARM the particles move along helical trajectories in a uniform magnetic field. Since it is much simpler to generate strong homogeneous magnetic fields than periodical ones for a relatively low electron energy ({Brit_pounds}{le}1-3 MeV) the period of particles` trajectories in the CARM can be sufficiently smaller than in the undulator in which, moreover, the field decreases rapidly in the transverse direction. In spite of this evident advantage, the number of papers on CARM is an order less than on ubitron, which is apparently caused by the low (not more than 10 %) CARM efficiency in experiments. At the same time, ubitrons operating in two rather complicated regimes-trapping and adiabatic deceleration of particles and combined undulator and reversed guiding fields - yielded efficiencies of 34 % and 27 %, respectively. The aim of this work is to demonstrate that high efficiency can be reached even for a simplest version of the CARM. In order to reduce sensitivity to an axial velocity spread of particles, a short interaction length where electrons underwent only 4-5 cyclotron oscillations was used in this work. Like experiments, a narrow anode outlet of a field-emission electron gun cut out the {open_quotes}most rectilinear{close_quotes} near-axis part of the electron beam. Additionally, magnetic field of a small correcting coil compensated spurious electron oscillations pumped by the anode aperture. A kicker in the form of a sloping to the axis frame with current provided a control value of rotary velocity at a small additional velocity spread. A simple cavity consisting of a cylindrical waveguide section restricted by a cut-off waveguide on the cathode side and by a Bragg reflector on the collector side was used as the CARM-oscillator microwave system.

  6. Lithium hydride doped intermediate connector for high-efficiency and long-term stable tandem organic light-emitting diodes.

    Science.gov (United States)

    Ding, Lei; Tang, Xun; Xu, Mei-Feng; Shi, Xiao-Bo; Wang, Zhao-Kui; Liao, Liang-Sheng

    2014-10-22

    Lithium hydride (LiH) is employed as a novel n-dopant in the intermediate connector for tandem organic light-emitting diodes (OLEDs) because of its easy coevaporation with other electron transporting materials. The tandem OLEDs with two and three electroluminescent (EL) units connected by a combination of LiH doped 8-hydroxyquinoline aluminum (Alq3) and 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN) demonstrate approximately 2-fold and 3-fold enhancement in current efficiency, respectively. In addition, no extra voltage drop across the intermediate connector is observed. Particularly, the lifetime (T75%) in the tandem OLED with two and three EL units is substantially improved by 3.8 times and 7.4 times, respectively. The doping effect of LiH into Alq3, the charge injection, and transport characteristics of LiH-doped Alq3 are further investigated by ultraviolet photoelectron spectroscopy (UPS) and X-ray photoemission spectroscopy (XPS).

  7. Manipulation of Thermally Activated Delayed Fluorescence of Blue Exciplex Emission: Fully Utilizing Exciton Energy for Highly Efficient Organic Light Emitting Diodes with Low Roll-Off.

    Science.gov (United States)

    Wang, Zixing; Wang, Hedan; Zhu, Jun; Wu, Peng; Shen, Bowen; Dou, Dehai; Wei, Bin

    2017-06-28

    The application of exciplex energy has become a unique way to achieve organic light-emitting diodes (OLEDs) with high efficiencies, low turn-on voltage, and low roll-off. Novel δ-carboline derivatives with high triplet energy (T 1 ≈ 2.92 eV) and high glass transition temperature (T g ≈ 153 °C) were employed to manipulate exciplex emissions in this paper. Deep blue (peak at 436 nm) and pure blue (peak at 468 nm) thermally activated delayed fluorescence (TADF) of exciplex OLEDs were demonstrated by utilizing them as emitters with the maximum current efficiency (CE) of 4.64 cd A -1 , power efficiency (PE) of 2.91 lm W -1 , and external quantum efficiency (EQE) of 2.36%. Highly efficient blue phosphorescent OLEDs doped with FIrpic showed a maximum CE of 55.6 cd A -1 , PE of 52.9 lm W -1 , and EQE of 24.6% respectively with very low turn on voltage at 2.7 V. The devices still remain high CE of 46.5 cd A -1 at 100 cd m -2 , 45.4 cd A -1 at 1000 cd m -2 and 42.3 cd A -1 at 5000 cd m -2 with EQE close to 20% indicating low roll-off. Manipulating blue exciplex emissions by chemical structure gives an ideal strategy to fully utilize all exciton energies for lighting of OLEDs.

  8. Highly efficient and concentration-insensitive organic light-emitting devices based on self-quenching-resistant orange–red iridium complex

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Yige; Wang, Xu [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Li, Ming [College of Chemistry, Sichuan University, Chengdu 610064 (China); Lu, Zhiyun, E-mail: luzhiyun@scu.edu.cn [College of Chemistry, Sichuan University, Chengdu 610064 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

    2014-11-15

    Orange–red phosphorescent organic light-emitting devices (PHOLEDs) with high efficiency and concentration insensitivity based on a novel iridium complex, bis[2-(biphenyl-4-yl)benzothiazole-N,C{sup 2}′]iridium(III) (acetylacetonate) [(4Phbt){sub 2}Ir(acac)], were fabricated. With the heavily doped emissive layer (EML) of 4,4′-N,N′-dicarbazolylbiphenyl (CBP): (4Phbt){sub 2}Ir(acac) in a wide and easily controlled dopant concentration range from 12 wt% to 24 wt%, a maximum power efficiency of 29 lm/W and an external quantum efficiency of >16% of the PHOLEDs were obtained, implying the insensitivity of electroluminescence (EL) properties to doping concentration. Meanwhile, a maximum power efficiency of 5.0 lm/W was achieved from a non-doped device with neat (4Phbt){sub 2}Ir(acac) as the EML, indicating a superior property of self-quenching resistance. The mechanism of direct exciton formation, in which exciton-formation regions are distributed throughout the EML, is responsible for the significant alleviation of triplet–triplet annihilation and superior EL performance. - Highlights: • Highly efficient and concentration-insensitive PHOLEDs were obtained. • The high efficiency of non-doped PHOLEDs indicated a quenching-resistant property. • The independence of EL spectra on doping concentration was observed. • The heavily doped devices were dominated by mechanism of direct exciton formation.

  9. Highly efficient nonprecious metal catalyst prepared with metal–organic framework in a continuous carbon nanofibrous network

    Science.gov (United States)

    Shui, Jianglan; Chen, Chen; Grabstanowicz, Lauren; Zhao, Dan; Liu, Di-Jia

    2015-01-01

    Fuel cell vehicles, the only all-electric technology with a demonstrated >300 miles per fill travel range, use Pt as the electrode catalyst. The high price of Pt creates a major cost barrier for large-scale implementation of polymer electrolyte membrane fuel cells. Nonprecious metal catalysts (NPMCs) represent attractive low-cost alternatives. However, a significantly lower turnover frequency at the individual catalytic site renders the traditional carbon-supported NPMCs inadequate in reaching the desired performance afforded by Pt. Unconventional catalyst design aiming at maximizing the active site density at much improved mass and charge transports is essential for the next-generation NPMC. We report here a method of preparing highly efficient, nanofibrous NPMC for cathodic oxygen reduction reaction by electrospinning a polymer solution containing ferrous organometallics and zeolitic imidazolate framework followed by thermal activation. The catalyst offers a carbon nanonetwork architecture made of microporous nanofibers decorated by uniformly distributed high-density active sites. In a single-cell test, the membrane electrode containing such a catalyst delivered unprecedented volumetric activities of 3.3 A⋅cm−3 at 0.9 V or 450 A⋅cm−3 extrapolated at 0.8 V, representing the highest reported value in the literature. Improved fuel cell durability was also observed. PMID:26261338

  10. Exciplex-Forming Co-Host-Based Red Phosphorescent Organic Light-Emitting Diodes with Long Operational Stability and High Efficiency.

    Science.gov (United States)

    Lee, Jeong-Hwan; Shin, Hyun; Kim, Jae-Min; Kim, Kwon-Hyeon; Kim, Jang-Joo

    2017-02-01

    The use of exciplex forming cohosts and phosphors incredibly boosts the efficiency of organic light-emitting diodes (OLEDs) by providing a barrier-free charge injection into an emitting layer and a broad recombination zone. However, most of the efficient OLEDs based on the exciplex forming cohosts has suffered from the short operational lifetime. Here, we demonstrated phosphorescent OLEDs (PhOLEDs) having both high efficiency and long lifetime by using a new exciplex forming cohost composed of N,N'-diphenyl-N,N'-bis(1,1'-biphenyl)-4,4'-diamine (NPB) and (1,3,5-triazine-2,4,6-triyl)tris(benzene-3,1-diyl))tris(diphenylphosphine oxide) (PO-T2T). The red-emitting PhOLEDs using the exciplex forming cohost achieved a maximum external quantum efficiency (EQE) of 34.1% and power efficiency of 62.2 lm W 1- with low operating voltages and low efficiency roll-offs. More importantly, the device demonstrated a long lifetime around 2249 h from 1000 cd m -2 to 900 cd m -2 (LT 90 ) under a continuous flow of constant current. The efficiencies of the devices are the highest for red OLEDs with an LT 90 > 1000 h.

  11. Reducing the efficiency–stability–cost gap of organic photovoltaics with highly efficient and stable small molecule acceptor ternary solar cells

    KAUST Repository

    Baran, Derya

    2016-11-21

    Technological deployment of organic photovoltaic modules requires improvements in device light-conversion efficiency and stability while keeping material costs low. Here we demonstrate highly efficient and stable solar cells using a ternary approach, wherein two non-fullerene acceptors are combined with both a scalable and affordable donor polymer, poly(3-hexylthiophene) (P3HT), and a high-efficiency, low-bandgap polymer in a single-layer bulk-heterojunction device. The addition of a strongly absorbing small molecule acceptor into a P3HT-based non-fullerene blend increases the device efficiency up to 7.7 ± 0.1% without any solvent additives. The improvement is assigned to changes in microstructure that reduce charge recombination and increase the photovoltage, and to improved light harvesting across the visible region. The stability of P3HT-based devices in ambient conditions is also significantly improved relative to polymer:fullerene devices. Combined with a low-bandgap donor polymer (PBDTTT-EFT, also known as PCE10), the two mixed acceptors also lead to solar cells with 11.0 ± 0.4% efficiency and a high open-circuit voltage of 1.03 ± 0.01 V.

  12. Reducing the efficiency–stability–cost gap of organic photovoltaics with highly efficient and stable small molecule acceptor ternary solar cells

    KAUST Repository

    Baran, Derya; Ashraf, Raja; Hanifi, David A.; Abdelsamie, Maged; Gasparini, Nicola; Rö hr, Jason A.; Holliday, Sarah; Wadsworth, Andrew; Lockett, Sarah; Neophytou, Marios; Emmott, Christopher J. M.; Nelson, Jenny; Brabec, Christoph J.; Amassian, Aram; Salleo, Alberto; Kirchartz, Thomas; Durrant, James R.; McCulloch, Iain

    2016-01-01

    Technological deployment of organic photovoltaic modules requires improvements in device light-conversion efficiency and stability while keeping material costs low. Here we demonstrate highly efficient and stable solar cells using a ternary approach, wherein two non-fullerene acceptors are combined with both a scalable and affordable donor polymer, poly(3-hexylthiophene) (P3HT), and a high-efficiency, low-bandgap polymer in a single-layer bulk-heterojunction device. The addition of a strongly absorbing small molecule acceptor into a P3HT-based non-fullerene blend increases the device efficiency up to 7.7 ± 0.1% without any solvent additives. The improvement is assigned to changes in microstructure that reduce charge recombination and increase the photovoltage, and to improved light harvesting across the visible region. The stability of P3HT-based devices in ambient conditions is also significantly improved relative to polymer:fullerene devices. Combined with a low-bandgap donor polymer (PBDTTT-EFT, also known as PCE10), the two mixed acceptors also lead to solar cells with 11.0 ± 0.4% efficiency and a high open-circuit voltage of 1.03 ± 0.01 V.

  13. Bipyridine- and phenanthroline-based metal-organic frameworks for highly efficient and tandem catalytic organic transformations via directed C-H activation

    Energy Technology Data Exchange (ETDEWEB)

    Manna, Kuntal [Univ. of Chicago, Chicago, IL (United States); Zhang, Teng [Univ. of Chicago, Chicago, IL (United States); Greene, Francis X. [Univ. of Chicago, Chicago, IL (United States); Lin, Wenbin [Univ. of Chicago, Chicago, IL (United States)

    2015-02-16

    We report here the synthesis of a series of robust and porous bipyridyl- and phenanthryl-based metal–organic frameworks (MOFs) of UiO topology (BPV-MOF, mBPV-MOF, and mPT-MOF) and their postsynthetic metalation to afford highly active single-site solid catalysts. While BPV-MOF was constructed from only bipyridyl-functionalized dicarboxylate linker, both mBPV- and mPT-MOF were built with a mixture of bipyridyl- or phenanthryl-functionalized and unfunctionalized dicarboxylate linkers. The postsynthetic metalation of these MOFs with [Ir(COD)(OMe)]2 provided Ir-functionalized MOFs (BPV-MOF-Ir, mBPV-MOF-Ir, and mPT-MOF-Ir), which are highly active catalysts for tandem hydrosilylation of aryl ketones and aldehydes followed by dehydrogenative ortho-silylation of benzylicsilyl ethers as well as C–H borylation of arenes using B₂pin₂. Both mBPV-MOF-Ir and mPT-MOF-Ir catalysts displayed superior activities compared to BPV-MOF-Ir due to the presence of larger open channels in the mixed-linker MOFs. Impressively, mBPV-MOF-Ir exhibited high TONs of up to 17000 for C–H borylation reactions and was recycled more than 15 times. The mPT-MOF-Ir system is also active in catalyzing tandem dehydrosilylation/dehydrogenative cyclization of N-methylbenzyl amines to azasilolanes in the absence of a hydrogen acceptor. Importantly, MOF-Ir catalysts are significantly more active (up to 95 times) and stable than their homogeneous counterparts for all three reactions, strongly supporting the beneficial effects of active site isolation within MOFs. This work illustrates the ability to increase MOF open channel sizes by using the mixed linker approach and shows the enormous potential of developing highly active and robust single-site solid catalysts based on MOFs containing nitrogen-donor ligands for important organic transformations.

  14. Factors limiting device efficiency in organic photovoltaics

    NARCIS (Netherlands)

    Janssen, R.A.J.; Nelson, J.

    2013-01-01

    The power conversion efficiency of the most efficient organic photovoltaic (OPV) cells has recently increased to over 10%. To enable further increases, the factors limiting the device efficiency in OPV must be identified. In this review, the operational mechanism of OPV cells is explained and the

  15. Efficiency roll-off suppression in organic light-emitting diodes using size-tunable bimetallic bowtie nanoantennas at high current densities

    International Nuclear Information System (INIS)

    Zhao, Yukun; Yun, Feng; Li, Yufeng; Feng, Lungang; Ding, Wen; Huang, Yi; Wu, Zhaoxin; Jiao, Bo; Li, Sanfeng; Zhang, Ye

    2016-01-01

    Size-tunable bimetallic bowtie nanoantennas have been utilized to suppress the efficiency roll-off characteristics in organic light-emitting diodes (OLEDs) using both the numerical and experimental approaches. The resonant range can be widened by the strong dual-atomic couplings in bimetallic bowtie nanoantennas. Compared with the green OLED with conventional bowtie nanoantennas at a high current density of 800 mA/cm"2, the measured efficiency roll-off ratio of the OLED with size-modulated bowtie nanoantennas is decreased from 53.2% to 41.8%, and the measured current efficiency is enhanced by 29.9%. When the size-modulated bowtie nanoantennas are utilized in blue phosphorescent OLEDs, the experimental roll-off ratio is suppressed from 43.6% to 25.9% at 250 mA/cm"2, and the measured current efficiency is also enhanced significantly. It is proposed that the efficiency roll-off suppression is mainly related to the enhanced localized surface plasmon effect, which leads to a shorter radiative lifetime.

  16. Efficiency roll-off suppression in organic light-emitting diodes using size-tunable bimetallic bowtie nanoantennas at high current densities

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yukun [Key Laboratory of Physical Electronics and Devices of Ministry of Education and Shaanxi Provincial Key Laboratory of Photonics & Information Technology, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Solid-State Lighting Engineering Research Center, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ (United Kingdom); Yun, Feng, E-mail: fyun2010@mail.xjtu.edu.cn; Li, Yufeng; Feng, Lungang; Ding, Wen [Key Laboratory of Physical Electronics and Devices of Ministry of Education and Shaanxi Provincial Key Laboratory of Photonics & Information Technology, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Solid-State Lighting Engineering Research Center, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Huang, Yi [Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ (United Kingdom); Wu, Zhaoxin; Jiao, Bo; Li, Sanfeng [Key Laboratory of Physical Electronics and Devices of Ministry of Education and Shaanxi Provincial Key Laboratory of Photonics & Information Technology, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Zhang, Ye [Solid-State Lighting Engineering Research Center, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China)

    2016-07-04

    Size-tunable bimetallic bowtie nanoantennas have been utilized to suppress the efficiency roll-off characteristics in organic light-emitting diodes (OLEDs) using both the numerical and experimental approaches. The resonant range can be widened by the strong dual-atomic couplings in bimetallic bowtie nanoantennas. Compared with the green OLED with conventional bowtie nanoantennas at a high current density of 800 mA/cm{sup 2}, the measured efficiency roll-off ratio of the OLED with size-modulated bowtie nanoantennas is decreased from 53.2% to 41.8%, and the measured current efficiency is enhanced by 29.9%. When the size-modulated bowtie nanoantennas are utilized in blue phosphorescent OLEDs, the experimental roll-off ratio is suppressed from 43.6% to 25.9% at 250 mA/cm{sup 2}, and the measured current efficiency is also enhanced significantly. It is proposed that the efficiency roll-off suppression is mainly related to the enhanced localized surface plasmon effect, which leads to a shorter radiative lifetime.

  17. Highly Efficient Interception and Precipitation of Uranium(VI) from Aqueous Solution by Iron-Electrocoagulation Combined with Cooperative Chelation by Organic Ligands.

    Science.gov (United States)

    Li, Peng; Zhun, Bao; Wang, Xuegang; Liao, PingPing; Wang, Guanghui; Wang, Lizhang; Guo, Yadan; Zhang, Weimin

    2017-12-19

    A new strategy combining iron-electrocoagulation and organic ligands (OGLs) cooperative chelation was proposed to screen and precipitate low concentrations (0-18.52 μmol/L) of uranium contaminant in aqueous solution. We hypothesized that OGLs with amino, hydroxyl, and carboxyl groups hydrophobically/hydrophilically would realize precuring of uranyl ion at pH electrocoagulation would achieve faster and more efficient uranium precipitation. Experimentally, the strategy demonstrated highly efficient uranium(VI) precipitation efficiency, especially with hydrophilic macromolecular OGLs. The uranium removal efficiency at optimized experimental condition reached 99.65%. The decrease of zeta potential and the lattice enwrapping between U-OGLs chelates and flocculation precursor were ascribed to the enhanced uranium precipitation activity. Uranium was precipitated as oxides of U(VI) or higher valences that were easily captured in aggregated micelles under low operation current potential. The actual uranium tailing wastewater was treated, and a satisfied uranium removal efficiency of 99.02% was discovered. After elution of the precipitated flocs, a concentrated uranium solution (up to 106.52 μmol/L) with very few other metallic impurities was obtained. Therefore, the proposed strategy could remove uranium and concentrate it concurrently. This work could provide new insights into the purification and recovery of uranium from aqueous solutions in a cost-effective and environmentally friendly process.

  18. MoO3–Au composite interfacial layer for high efficiency and air-stable organic solar cells

    DEFF Research Database (Denmark)

    Pan, Hongbin; Zuo, Lijian; Fu, Weifei

    2013-01-01

    Efficient and stable polymer bulk-heterojunction solar cells based on regioregular poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PC61BM) blend active layer have been fabricated with a MoO3–Au co-evaporation composite film as the anode interfacial layer (AIL). The optical...

  19. An Al-doped ZnO electrode grown by highly efficient cylindrical rotating magnetron sputtering for low cost organic photovoltaics

    Science.gov (United States)

    Park, Jun-Hyuk; Ahn, Kyung-Jun; Park, Kang-Il; Na, Seok-In; Kim, Han-Ki

    2010-03-01

    We report the characteristics of Al-doped zinc oxide (AZO) films prepared by a highly efficient cylindrical rotating magnetron sputtering (CRMS) system for use as a transparent conducting electrode in cost-efficient bulk hetero-junction organic solar cells (OSCs). Using a rotating cylindrical type cathode with an AZO target, whose usage was above 80%, we were able to obtain a low cost and indium free AZO electrode with a low sheet resistance of ~4.59 Ω/sq, a high transparency of 85% in the visible wavelength region and a work function of 4.9 eV at a substrate temperature of 230 °C. Moreover, the neutral poly(3,4-ethylenedioxythiophene) : poly(styrenesulfonate) based OSC fabricated on the CRMS-grown AZO electrode at 230 °C showed an open circuit voltage of 0.5 V, a short circuit current of 8.94 mA cm-2, a fill factor of 45% and power conversion efficiency of 2.01%, indicating that CRMS is a promising cost-efficient AZO deposition technique for low cost OSCs.

  20. High efficiency orange-red phosphorescent organic light emitting diodes based on a Pt(II)-pyridyltriazolate complex from a structure optimized for charge balance and reduced efficiency roll-off

    Energy Technology Data Exchange (ETDEWEB)

    Li, Minghang; Lin, Ming-Te; Shepherd, Nigel D. [Department of Material Science and Engineering, University of North Texas, Denton, Texas (United States); Chen, Wei-Hsuan; McDougald, Roy Jr.; Arvapally, Ravi; Omary, Mohammad [Department of Chemistry, University of North Texas, Denton, Texas (United States)

    2012-01-15

    We report a high power efficiency (PE) of 44.7 {+-} 0.5 lm/W, high external quantum efficiency (EQE) of 19.7 {+-} 0.1% at 500 Cd/m{sup 2}, and efficiency roll-off of only 4% of the peak value at a useful brightness of 1000 Cd/m{sup 2} from orange-red emitting, organic light emitting diodes featuring 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) as the hole transport layer/electron blocking layer, an emissive layer consisting of 65% bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II) (Pt(ptp){sub 2}) doped into 4,4'-bis(carbazol-9-yl)triphenylamine (CBP), and 1,3,5-tris(phenyl-2-benzimidazolyl)-benzene (TPBI) as the electron transport layer (ETL). Based on a comparison of these structures with devices that did not incorporate an electron/exciton blocker and devices featuring N,N'-dicarbazolyl-3,5-benzene (mCP) as the electron/exciton blocking layer, we ascribe the high efficiency and low efficiency roll-off to better charge balance, and enhanced confinement of excitons and the recombination zone to the emissive layer. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. High efficiency positron moderation

    International Nuclear Information System (INIS)

    Taqqu, D.

    1990-01-01

    A new positron moderation scheme is proposed. It makes use of electric and magnetic fields to confine the β + emitted by a radioactive source forcing them to slow down within a thin foil. A specific arrangement is described where an intermediary slowed-down beam of energy below 10 keV is produced. By directing it towards a standard moderator optimal conversion into slow positrons is achieved. This scheme is best applied to short lived β + emitters for which a 25% moderation efficiency can be reached. Within the state of the art technology a slow positron source intensity exceeding 2 x 10 10 e + /sec is achievable. (orig.)

  2. Highly Simplified Tandem Organic Light-Emitting Devices Incorporating a Green Phosphorescence Ultrathin Emitter within a Novel Interface Exciplex for High Efficiency.

    Science.gov (United States)

    Xu, Ting; Zhou, Jun-Gui; Huang, Chen-Chao; Zhang, Lei; Fung, Man-Keung; Murtaza, Imran; Meng, Hong; Liao, Liang-Sheng

    2017-03-29

    Herein we report a novel design philosophy of tandem OLEDs incorporating a doping-free green phosphorescent bis[2-(2-pyridinyl-N)phenyl-C](acetylacetonato)iridium(III) (Ir(ppy) 2 (acac)) as an ultrathin emissive layer (UEML) into a novel interface-exciplex-forming structure of 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) and 1,3,5-tri(p-pyrid-3-yl-phenyl)benzene (TmPyPB). Particularly, relatively low working voltage and remarkable efficiency are achieved and the designed tandem OLEDs exhibit a peak current efficiency of 135.74 cd/A (EQE = 36.85%) which is two times higher than 66.2 cd/A (EQE = 17.97%) of the device with a single emitter unit. This might be one of the highest efficiencies of OLEDs applying ultrathin emitters without light extraction. Moreover, with the proposed structure, the color gamut of the displays can be effectively increased from 76% to 82% NTSC if the same red and blue emissions as those in the NTSC are applied. A novel form of harmonious fusion among interface exciplex, UEML, and tandem structure is successfully realized, which sheds light on further development of ideal OLED structure with high efficiency, simplified fabrication, low power consumption, low cost, and improved color gamut, simultaneously.

  3. High efficiency scintillation detectors

    International Nuclear Information System (INIS)

    Noakes, J.E.

    1976-01-01

    A scintillation counter consisting of a scintillation detector, usually a crystal scintillator optically coupled to a photomultiplier tube which converts photons to electrical pulses is described. The photomultiplier pulses are measured to provide information on impinging radiation. In inorganic crystal scintillation detectors to achieve maximum density, optical transparency and uniform activation, it has been necessary heretofore to prepare the scintillator as a single crystal. Crystal pieces fail to give a single composite response. Means are provided herein for obtaining such a response with crystal pieces, such means comprising the combination of crystal pieces and liquid or solid organic scintillator matrices having a cyclic molecular structure favorable to fluorescence. 8 claims, 6 drawing figures

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

    International Nuclear Information System (INIS)

    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.

  5. Utilizing a Spiro Core with Acridine- and Phenothiazine-Based New Hole Transporting Materials for Highly Efficient Green Phosphorescent Organic Light-Emitting Diodes

    Directory of Open Access Journals (Sweden)

    Ramanaskanda Braveenth

    2018-03-01

    Full Text Available Two new hole transporting materials, 2,7-bis(9,9-diphenylacridin-10(9H-yl-9,9′ spirobi[fluorene] (SP1 and 2,7-di(10H-phenothiazin-10-yl-9,9′-spirobi[fluorene] (SP2, were designed and synthesized by using the Buchwald–Hartwig coupling reaction with a high yield percentage of over 84%. Both of the materials exhibited high glass transition temperatures of over 150 °C. In order to understand the device performances, we have fabricated green phosphorescent organic light-emitting diodes (PhOLEDs with SP1 and SP2 as hole transporting materials. Both of the materials revealed improved device properties, in particular, the SP2-based device showed excellent power (34.47 lm/W and current (38.41 cd/A efficiencies when compare with the 4,4′-bis(N-phenyl-1-naphthylaminobiphenyl (NPB-based reference device (30.33 lm/W and 32.83 cd/A. The external quantum efficiency (EQE of SP2 was 13.43%, which was higher than SP1 (13.27% and the reference material (11.45% with a similar device structure. The SP2 hole transporting material provides an effective charge transporting path from anode to emission layer, which is explained by the device efficiencies.

  6. Hydrogenated TiO{sub 2} nanobelts as highly efficient photocatalytic organic dye degradation and hydrogen evolution photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Jian [School of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao 266590 (China); State key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Leng, Yanhua [State key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Cui, Hongzhi, E-mail: cuihongzhi1965@163.com [School of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao 266590 (China); Liu, Hong, E-mail: hongliu@sdu.edu.cn [State key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China)

    2015-12-15

    Highlights: • A facile synthesis of hydrogenated TiO{sub 2} nanobelts is reported. • Utilizing UV and visible light in photocatalytic degradation and H{sub 2} production. • The improved photocatalytic property is owe to Ti{sup 3+} ions and oxygen vacancies. - Abstract: TiO{sub 2} nanobelts have gained increasing interest because of its outstanding properties and promising applications in a wide range of fields. Here we report the facile synthesis of hydrogenated TiO{sub 2} (H-TiO{sub 2}) nanobelts, which exhibit excellent UV and visible photocatalytic decomposing of methyl orange (MO) and water splitting for hydrogen production. The improved photocatalytic property can be attributed to the Ti{sup 3+} ions and oxygen vacancies in TiO{sub 2} nanobelts created by hydrogenation. Ti{sup 3+} ions and oxygen vacancies can enhance visible light absorption, promote charge carrier trapping, and hinder the photogenerated electron–hole recombination. This work offers a simple strategy for the fabrication of a wide solar spectrum of active photocatalysts, which possesses significant potential for more efficient photodegradation, photocatalytic water splitting, and enhanced solar cells using sunlight as light source.

  7. Out-coupling membrane for large-size organic light-emitting panels with high efficiency and improved uniformity

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Lei, E-mail: dinglei@sust.edu.cn [College of Electrical and Information Engineering, Shaanxi University of Science and Technology, Xi’an, Shaanxi 710021 (China); Wang, Lu-Wei [College of Electrical and Information Engineering, Shaanxi University of Science and Technology, Xi’an, Shaanxi 710021 (China); Zhou, Lei, E-mail: zhzhlei@gmail.com [Faculty of Mathematics and Physics, Huaiyin Institute of Technology, Huai' an 223003 (China); Zhang, Fang-hui [College of Electrical and Information Engineering, Shaanxi University of Science and Technology, Xi’an, Shaanxi 710021 (China)

    2016-12-15

    Highlights: • An out-coupling membrane embedded with a scattering film of SiO{sub 2} spheres and polyethylene terephthalate (PET) plastic was successfully developed for 150 × 150 mm{sup 2} OLEDs. • Remarkable enhancement in efficiency was achieved from the OLEDs with out- coupling membrane. • The uniformity of large-size GOLED lighting panel is remarkably improved. - Abstract: An out-coupling membrane embedded with a scattering film of SiO{sub 2} spheres and polyethylene terephthalate (PET) plastic was successfully developed for 150 × 150 mm{sup 2} green OLEDs. Comparing with a reference OLED panel, an approximately 1-fold enhancement in the forward emission was obtained with an out-coupling membrane adhered to the surface of the external glass substrate of the panel. Moreover, it was verified that the emission color at different viewing angles can be stabilized without apparent spectral distortion. Particularly, the uniformity of the large-area OLEDs was greatly improved. Theoretical calculation clarified that the improved performance of the lighting panels is primarily attributed to the effect of particle scattering.

  8. Can radiation chemistry supply a highly efficient AO(R)P process for organics removal from drinking and waste water? A review.

    Science.gov (United States)

    Trojanowicz, Marek; Bojanowska-Czajka, Anna; Capodaglio, Andrea G

    2017-09-01

    The increasing role of chemistry in industrial production and its direct and indirect impacts in everyday life create the need for continuous search and efficiency improvement of new methods for decomposition/removal of different classes of waterborne anthropogenic pollutants. This review paper addresses a highly promising class of water treatment solutions, aimed at tackling the pressing problem of emerging contaminants in natural and drinking waters and wastewater discharges. Radiation processing, a technology originating from radiation chemistry studies, has shown encouraging results in the treatment of (mainly) organic water pollution. Radiation ("high energy") processing is an additive-free technology using short-lived reactive species formed by the radiolysis of water, both oxidative and reducing, to carry out decomposition of organic pollutants. The paper illustrates the basic principles of radiolytic treatment of organic pollutants in water and wastewaters and specifically of one of its most practical implementations (electron beam processing). Application examples, highlighting the technology's strong points and operational conditions are described, and a discussion on the possible future of this technology follows.

  9. High-efficiency photovoltaic cells

    Science.gov (United States)

    Yang, H.T.; Zehr, S.W.

    1982-06-21

    High efficiency solar converters comprised of a two cell, non-lattice matched, monolithic stacked semiconductor configuration using optimum pairs of cells having bandgaps in the range 1.6 to 1.7 eV and 0.95 to 1.1 eV, and a method of fabrication thereof, are disclosed. The high band gap subcells are fabricated using metal organic chemical vapor deposition (MOCVD), liquid phase epitaxy (LPE) or molecular beam epitaxy (MBE) to produce the required AlGaAs layers of optimized composition, thickness and doping to produce high performance, heteroface homojunction devices. The low bandgap subcells are similarly fabricated from AlGa(As)Sb compositions by LPE, MBE or MOCVD. These subcells are then coupled to form a monolithic structure by an appropriate bonding technique which also forms the required transparent intercell ohmic contact (IOC) between the two subcells. Improved ohmic contacts to the high bandgap semiconductor structure can be formed by vacuum evaporating to suitable metal or semiconductor materials which react during laser annealing to form a low bandgap semiconductor which provides a low contact resistance structure.

  10. Color-Tunable and High-Efficiency Dye-Encapsulated Metal-Organic Framework Composites Used for Smart White-Light-Emitting Diodes.

    Science.gov (United States)

    Chen, Wenwei; Zhuang, Yixi; Wang, Le; Lv, Ying; Liu, Jianbin; Zhou, Tian-Liang; Xie, Rong-Jun

    2018-05-25

    Luminescent metal-organic frameworks (MOFs) (typically dye-encapsulated MOFs) are considered as one kind of interesting downconversion materials for white-light-emitting diodes (LEDs), but their quantum efficiency (QE) is not sufficient and thus needs to be significantly enhanced for practical applications. In this study, we successfully synthesized a series of Rh@bio-MOF-1 (Rh = rhodamine) with an internal QE as high as ∼79% via a solvothermal reaction followed by cation exchanges. The high efficiency of the Rh@bio-MOF-1 composites was attributable to the high intrinsic luminescent efficiency of the selected Rh dyes, the confinement effect in the bio-MOF-1 host, and the uniform particle morphology. The emission maximum could be continuously tuned from 550 to 610 nm by controlling the species and concentration of encapsulated dye molecules, showing great color tunability of the dye-encapsulated MOFs. The emission lifetime of ∼7 ns was 1 or 2 magnitude orders shorter than that of Ce 3+ - or Eu 2+ -doped inorganic phosphors, allowing for visible light communication (VLC). White LEDs, fabricated by using the synthesized Rh@bio-MOF-1 composite and inorganic phosphors of green (Ba,Sr) 2 SiO 4 :Eu 2+ and red CaAlSiN 3 :Eu 2+ , exhibited a high color rendering index of 80-94, a luminous efficacy of 94-156 lm/W, and an excellent stability in color point against drive current. The Rh@bio-MOF-1 composites with tunable colors, short emission lifetime, and high QE are expected to be used for smart white LEDs with multifunctions of both lighting and VLC.

  11. Highly Flexible and Efficient Fabric-Based Organic Light-Emitting Devices for Clothing-Shaped Wearable Displays.

    Science.gov (United States)

    Choi, Seungyeop; Kwon, Seonil; Kim, Hyuncheol; Kim, Woohyun; Kwon, Jung Hyun; Lim, Myung Sub; Lee, Ho Seung; Choi, Kyung Cheol

    2017-07-25

    Recently, the role of clothing has evolved from merely body protection, maintaining the body temperature, and fashion, to advanced functions such as various types of information delivery, communication, and even augmented reality. With a wireless internet connection, the integration of circuits and sensors, and a portable power supply, clothes become a novel electronic device. Currently, the information display is the most intuitive interface using visualized communication methods and the simultaneous concurrent processing of inputs and outputs between a wearer and functional clothes. The important aspect in this case is to maintain the characteristic softness of the fabrics even when electronic devices are added to the flexible clothes. Silicone-based light-emitting diode (LED) jackets, shirts, and stage costumes have started to appear, but the intrinsic stiffness of inorganic semiconductors causes wearers to feel discomfort; thus, it is difficult to use such devices for everyday purposes. To address this problem, a method of fabricating a thin and flexible emitting fabric utilizing organic light-emitting diodes (OLEDs) was developed in this work. Its flexibility was evaluated, and an analysis of its mechanical bending characteristics and tests of its long-term reliability were carried out.

  12. Optical efficiency enhancement in white organic light-emitting diode display with high color gamut using patterned quantum dot film and long pass filter

    Science.gov (United States)

    Kim, Hyo-Jun; Shin, Min-Ho; Kim, Young-Joo

    2016-08-01

    A new structure for white organic light-emitting diode (OLED) displays with a patterned quantum dot (QD) film and a long pass filter (LPF) was proposed and evaluated to realize both a high color gamut and high optical efficiency. Since optical efficiency is a critical parameter in white OLED displays with a high color gamut, a red or green QD film as a color-converting component and an LPF as a light-recycling component are introduced to be adjusted via the characteristics of a color filter (CF). Compared with a conventional white OLED without both a QD film and the LPF, it was confirmed experimentally that the optical powers of red and green light in a new white OLED display were increased by 54.1 and 24.7% using a 30 wt % red QD film and a 20 wt % green QD film with the LPF, respectively. In addition, the white OLED with both a QD film and the LPF resulted in an increase in the color gamut from 98 to 107% (NTSC x,y ratio) due to the narrow emission linewidth of the QDs.

  13. Highly Efficient Solution-Processed Deep-Red Organic Light-Emitting Diodes Based on an Exciplex Host Composed of a Hole Transporter and a Bipolar Host.

    Science.gov (United States)

    Huang, Manli; Jiang, Bei; Xie, Guohua; Yang, Chuluo

    2017-10-19

    With the aim to achieve highly efficient deep-red emission, we introduced an exciplex forming cohost, 4,4',4″-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA): 2,5-bis(2-(9H-carbazol-9-yl)phenyl)-1,3,4-oxadiazole (o-CzOXD) (1:1). Due to the efficient triplet up-conversion processes upon the exciplex forming cohost, excellent performances of the devices were achieved with deep-red emission. Using the heteroleptic iridium complexes as the guest dopants, the solution-processed deep-red phosphorescent organic light-emitting diodes (PhOLEDs) with the iridium(III) bis(6-(4-(tert-butyl)phenyl)phenanthridine)acetylacetonate [(TP-BQ) 2 Ir(acac)]-based phosphorescent emitter exhibited an electroluminescent peak at 656 nm and a maximum external quantum efficiency (EQE) of 11.9%, which is 6.6 times that of the device based on the guest emitter doped in the polymer-based cohost. The unique exciplex with a typical hole transporter and a bipolar material is ideal and universal for hosting the red PhOLEDs and tremendously improves the device performances.

  14. A Zero-Dimensional Organic Seesaw-Shaped Tin Bromide with Highly Efficient Strongly Stokes-Shifted Deep-Red Emission

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Chenkun [College of Engineering, Tallahassee, FL (United States). Dept. of Chemical and Biomedical Engineering; Lin, Haoran [College of Engineering, Tallahassee, FL (United States). Dept. of Chemical and Biomedical Engineering; Shi, Hongliang [Beihang Univ., Beijing (China). Dept. of Physics; Tian, Yu [Materials Science and Engineering Program, Florida State University, Tallahassee FL 32306 USA; Pak, Chongin [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry; Shatruk, Michael [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry; Zhou, Yan [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry; Djurovich, Peter [Univ. of Southern California, Los Angeles, CA (United States). Dept. of Chemistry; Du, Mao-Hua [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division, Center for Radiation Detection Materials and Systems; Ma, Biwu [College of Engineering, Tallahassee, FL (United States). Dept. of Chemical and Biomedical Engineering; Beihang Univ., Beijing (China). Dept. of Physics; Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry

    2017-12-21

    The synthesis and characterization is reported of (C9NH20)2SnBr4, a novel organic metal halide hybrid with a zero-dimensional (0D) structure, in which individual seesaw-shaped tin (II) bromide anions (SnBr42-) are co-crystallized with 1-butyl-1-methylpyrrolidinium cations (C9NH20+). Upon photoexcitation, the bulk crystals exhibit a highly efficient broadband deep-red emission peaked at 695 nm, with a large Stokes shift of 332 nm and a high quantum efficiency of around 46 %. Furthermore, the unique photophysical properties of this hybrid material are attributed to two major factors: 1) the 0D structure allowing the bulk crystals to exhibit the intrinsic properties of individual SnBr42- species, and 2) the seesaw structure then enables a pronounced excited state structural deformation as confirmed by density functional theory (DFT) calculations.

  15. High-efficiency tris(8-hydroxyquinoline)aluminum (Alq3) complexes for organic white-light-emitting diodes and solid-state lighting.

    Science.gov (United States)

    Pérez-Bolívar, César; Takizawa, Shin-ya; Nishimura, Go; Montes, Victor A; Anzenbacher, Pavel

    2011-08-08

    Combinations of electron-withdrawing and -donating substituents on the 8-hydroxyquinoline ligand of the tris(8-hydroxyquinoline)aluminum (Alq(3)) complexes allow for control of the HOMO and LUMO energies and the HOMO-LUMO gap responsible for emission from the complexes. Here, we present a systematic study on tuning the emission and electroluminescence (EL) from Alq(3) complexes from the green to blue region. In this study, we explored the combination of electron-donating substituents on C4 and C6. Compounds 1-6 displayed the emission tuning between 478 and 526 nm, and fluorescence quantum yield between 0.15 and 0.57. The compounds 2-6 were used as emitters and hosts in organic light-emitting diodes (OLEDs). The highest OLED external quantum efficiency (EQE) observed was 4.6%, which is among the highest observed for Alq(3) complexes. Also, the compounds 3-5 were used as hosts for red phosphorescent dopants to obtain white light-emitting diodes (WOLED). The WOLEDs displayed high efficiency (EQE up to 19%) and high white color purity (color rendering index (CRI≈85). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. New highly efficient piezoceramic materials

    International Nuclear Information System (INIS)

    Dantsiger, A.Ya.; Razumovskaya, O.N.; Reznichenko, L.A.; Grineva, L.D.; Devlikanova, R.U.; Dudkina, S.I.; Gavrilyachenko, S.V.; Dergunova, N.V.

    1993-01-01

    New high efficient piezoceramic materials with various combination of parameters inclusing high Curie point for high-temperature transducers using in atomic power engineering are worked. They can be used in systems for heated matters nondestructive testing, controllers for varied industrial power plants and other high-temperature equipment

  17. Controlling the Morphology of BDTT-DPP-Based Small Molecules via End-Group Functionalization for Highly Efficient Single and Tandem Organic Photovoltaic Cells.

    Science.gov (United States)

    Kim, Ji-Hoon; Park, Jong Baek; Yang, Hoichang; Jung, In Hwan; Yoon, Sung Cheol; Kim, Dongwook; Hwang, Do-Hoon

    2015-11-04

    A series of narrow-band gap, π-conjugated small molecules based on diketopyrrolopyrrole (DPP) electron acceptor units coupled with alkylthienyl-substituted-benzodithiophene (BDTT) electron donors were designed and synthesized for use as donor materials in solution-processed organic photovoltaic cells. In particular, by end-group functionalization of the small molecules with fluorine derivatives, the nanoscale morphologies of the photoactive layers of the photovoltaic cells were successfully controlled. The influences of different fluorine-based end-groups on the optoelectronic and morphological properties, carrier mobilities, and the photovoltaic performances of these materials were investigated. A high power conversion efficiency (PCE) of 6.00% under simulated solar light (AM 1.5G) illumination has been achieved for organic photovoltaic cells based on a small-molecule bulk heterojunction system consisting of a trifluoromethylbenzene (CF3) end-group-containing oligomer (BDTT-(DPP)2-CF3) as the donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor. As a result, the introduction of CF3 end-groups has been found to enhance both the short circuit current density (JSC) and fill factor (FF). A tandem photovoltaic device comprising an inverted BDTT-(DPP)2-CF3:PC71BM cell and a poly(3-hexylthiophene) (P3HT):indene-C60-bisadduct (IC60BA)-based cell as the top and bottom cell components, respectively, showed a maximum PCE of 8.30%. These results provide valuable guidelines for the rational design of conjugated small molecules for applications in high-performance organic photovoltaic cells. Furthermore, to the best of our knowledge, this is the first report on the design of fluorine-functionalized BDTT-DPP-based small molecules, which have been shown to be a viable candidate for use in inverted tandem cells.

  18. High Piezo-photocatalytic Efficiency of CuS/ZnO Nanowires Using Both Solar and Mechanical Energy for Degrading Organic Dye.

    Science.gov (United States)

    Hong, Deyi; Zang, Weili; Guo, Xiao; Fu, Yongming; He, Haoxuan; Sun, Jing; Xing, Lili; Liu, Baodan; Xue, Xinyu

    2016-08-24

    High piezo-photocatalytic efficiency of degrading organic pollutants has been realized from CuS/ZnO nanowires using both solar and mechanical energy. CuS/ZnO heterostructured nanowire arrays are compactly/vertically aligned on stainless steel mesh by a simple two-step wet-chemical method. The mesh-supported nanocomposites can facilitate an efficient light harvesting due to the large surface area and can also be easily removed from the treated solution. Under both solar and ultrasonic irradiation, CuS/ZnO nanowires can rapidly degrade methylene blue (MB) in aqueous solution, and the recyclability is investigated. In this process, the ultrasonic assistance can greatly enhance the photocatalytic activity. Such a performance can be attributed to the coupling of the built-in electric field of heterostructures and the piezoelectric field of ZnO nanowires. The built-in electric field of the heterostructure can effectively separate the photogenerated electrons/holes and facilitate the carrier transportation. The CuS component can improve the visible light utilization. The piezoelectric field created by ZnO nanowires can further separate the photogenerated electrons/holes through driving them to migrate along opposite directions. The present results demonstrate a new water-pollution solution in green technologies for the environmental remediation at the industrial level.

  19. Organic contaminant removal efficiency of sodium bentonite/clay (BC) mixtures in high permeability regions utilizing reclaimed wastewater: A meso-scale study

    Science.gov (United States)

    Xiao, Yang; Li, Yunkai; Ning, Zigong; Li, Pengxiang; Yang, Peiling; Liu, Chengcheng; Liu, Zhongwei; Xu, Feipeng; Hynds, Paul Dylan

    2018-03-01

    Wastewater reclamation now represents an effective measure for sustainable water resource management in arid regions, however wastewater components (organic micropollutants) may potentially impact local ecological and/or human health. Previous studies have shown that sodium bentonite/natural clay (BC) mixes may be used to effectively reduce riverbed infiltration in regions characterized by excessively high hydraulic conductivity. Accordingly, the current study sought to investigate the contaminant removal efficiency (Re) of several BC mass ratios in simulated dry riverbeds. Results indicate that the measured Re of NH4+-N, CODcr and BOD5 increased in concurrence with an increasing sodium bentonite ratio, up to a maximum Re of 97.4% (NH4+-N), 55.2% (CODcr), and 51.5% (BOD5). The primary contaminant removal site was shown to be the infiltration-reducing (BC) layer, accounting for approximately 40%, 60%, and 70% of NH4+-N, CODcr and BOD5 removal, respectively. Conversely, the removal efficiency of NO3-N was found to be low (managing recharge of non-potable aquifers with reclaimed wastewater.

  20. High Power Efficiency Solution-Processed Blue Phosphorescent Organic Light-Emitting Diodes Using Exciplex-Type Host with a Turn-on Voltage Approaching the Theoretical Limit.

    Science.gov (United States)

    Ban, Xinxin; Sun, Kaiyong; Sun, Yueming; Huang, Bin; Ye, Shanghui; Yang, Min; Jiang, Wei

    2015-11-18

    Three solution-processable exciplex-type host materials were successfully designed and characterized by equal molar blending hole transporting molecules with a newly synthesized electron transporting material, which possesses high thermal stability and good film-forming ability through a spin-coating technique. The excited-state dynamics and the structure-property relationships were systematically investigated. By gradually deepening the highest occupied molecular orbital (HOMO) level of electron-donating components, the triplet energy of exciplex hosts were increased from 2.64 to 3.10 eV. Low temperature phosphorescence spectra demonstrated that the excessively high triplet energy of exciplex would induce a serious energy leakage from the complex state to the constituting molecule. Furthermore, the low energy electromer state, which only exists under the electroexcitation, was found as another possible channel for energy loss in exciplex-based phosphorescent organic light-emitting diodes (OLEDs). In particular, as quenching of the exciplex-state and the triplet exciton were largely eliminated, solution-processed blue phosphorescence OLEDs using the exciplex-type host achieved an extremely low turn-on voltage of 2.7 eV and record-high power efficiency of 22.5 lm W(-1), which were among the highest values in the devices with identical structure.

  1. How physicians' organizations compete: protectionism and efficiency.

    Science.gov (United States)

    Page, Stephen

    2004-02-01

    This article develops a framework that distinguishes four types of competitive strategies that physicians' organizations can adopt in their interactions with health plans. Two types of strategies protect physicians' incomes and autonomy from incursion and control by insurers; the other two enhance the efficiency of health care markets by controlling costs and embedding physicians' caregiving in a community of professionals. The mix of strategies that each organization adopts at any given time depends on the market conditions and regulatory policies it faces, as well as its organizational capacity. The article reviews recent developments in the field that indicate that today's markets and regulations create neither the pressures nor the capacity for physicians' organizations to adopt strategies that enhance efficiency. The managed care backlash has led to a relaxation of pressures to control costs, and the lack of a business case for quality has discouraged embedded caregiving. These developments instead have encouraged and enabled physicians' organizations to adopt strategies that protect their members from the bargaining power and micromanagement of health plans. The article therefore proposes changes in purchasing and regulatory policies to alter the pressures and improve the capacity of physicians' organizations to pursue efficiency and eschew protectionism.

  2. Exploiting multi-function Metal-Organic Framework nanocomposite Ag@Zn-TSA as highly efficient immobilization matrixes for sensitive electrochemical biosensing.

    Science.gov (United States)

    Dong, Sheying; Zhang, Dandan; Suo, Gaochao; Wei, Wenbo; Huang, Tinglin

    2016-08-31

    A novel multi-function Metal-Organic Framework composite Ag@Zn-TSA (zinc thiosalicylate, Zn(C7H4O2S), Zn-TSA) was synthesized as highly efficient immobilization matrixes of myoglobin (Mb)/glucose oxidase (GOx) for electrochemical biosensing. The electrochemical biosensors based on Ag@Zn-TSA composite and ionic liquid (IL) modified carbon paste electrode (CPE) were fabricated successfully. Furthermore, the properties of the sensors were discussed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and amperometric current-time curve, respectively. The results showed the proposed biosensors had wide linear response to hydrogen peroxide (H2O2) in the range of 0.3-20,000 μM, to nitrite (NO2(-)) for 1.3 μM-1660 μM and 2262 μM-1,33,000 μM, to glucose for 2.0-1022 μM, with a low detection limit of 0.08 μM for H2O2, 0.5 μM for NO2(-), 0.8 μM for glucose. The values of the apparent heterogeneous electron transfer rate constant (ks) for Mb and GOx were estimated as 2.05 s(-1) and 2.45 s(-1), respectively. Thus, Ag@Zn-TSA was a kind of ideal material as highly efficient immobilization matrixes for sensitive electrochemical biosensing. In addition, this work indicated that MOF nanocomposite had a great potential for constructing wide range of sensing interface. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Highly efficient Fenton and enzyme-mimetic activities of NH2-MIL-88B(Fe) metal organic framework for methylene blue degradation.

    Science.gov (United States)

    He, Jianchuan; Zhang, Yao; Zhang, Xiaodan; Huang, Yuming

    2018-03-26

    Here, we show that NH 2 -MIL-88B(Fe) can be used as a peroxidase-like catalyst for Fenton-like degradation of methylene blue (MB) in water. The iron-based NH 2 -MIL-88B(Fe) metal organic framework (MOF) was synthesized by a facile and rapid microwave heating method. It was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, powder X-ray diffraction, and the Brunauer-Emmett-Teller method. The NH 2 -MIL-88B(Fe) MOF possesses intrinsic oxidase-like and peroxidase-like activities. The reaction parameters that affect MB degradation were investigated, including the solution pH, NH 2 -MIL-88B(Fe) MOF and H 2 O 2 concentrations, and temperature. The results show that the NH 2 -MIL-88B(Fe) MOF exhibits a wide working pH range (pH 3.0-11.0), temperature tolerance, and good recyclability for MB removal. Under the optimal conditions, complete removal of MB was achieved within 45 min. In addition, removal of MB was above 80% after five cycles, showing the good recyclability of NH 2 -MIL-88B(Fe). The NH 2 -MIL-88B(Fe) MOF has the features of easy preparation, high efficiency, and good recyclability for MB removal in a wide pH range. Electron spin resonance and fluorescence probe results suggest the involvement of hydroxyl radicals in MB degradation. These findings provide new insight into the application of high-efficient MOF-based Fenton-like catalysts for water purification.

  4. Exploiting multi-function Metal-Organic Framework nanocomposite Ag@Zn-TSA as highly efficient immobilization matrixes for sensitive electrochemical biosensing

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Sheying, E-mail: dongsyy@126.com [College of Sciences, Xi' an University of Architecture and Technology, Xi' an, 710055 (China); Zhang, Dandan; Suo, Gaochao; Wei, Wenbo [College of Sciences, Xi' an University of Architecture and Technology, Xi' an, 710055 (China); Huang, Tinglin [School of Environmental and Municipal Engineering, Xi' an University of Architecture and Technology, Xi' an, 710055 (China)

    2016-08-31

    A novel multi-function Metal-Organic Framework composite Ag@Zn-TSA (zinc thiosalicylate, Zn(C{sub 7}H{sub 4}O{sub 2}S), Zn-TSA) was synthesized as highly efficient immobilization matrixes of myoglobin (Mb)/glucose oxidase (GOx) for electrochemical biosensing. The electrochemical biosensors based on Ag@Zn-TSA composite and ionic liquid (IL) modified carbon paste electrode (CPE) were fabricated successfully. Furthermore, the properties of the sensors were discussed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and amperometric current-time curve, respectively. The results showed the proposed biosensors had wide linear response to hydrogen peroxide (H{sub 2}O{sub 2}) in the range of 0.3–20,000 μM, to nitrite (NO{sub 2}{sup −}) for 1.3 μM–1660 μM and 2262 μM–1,33,000 μM, to glucose for 2.0–1022 μM, with a low detection limit of 0.08 μM for H{sub 2}O{sub 2}, 0.5 μM for NO{sub 2}{sup −}, 0.8 μM for glucose. The values of the apparent heterogeneous electron transfer rate constant (k{sub s}) for Mb and GOx were estimated as 2.05 s{sup −1} and 2.45 s{sup −1}, respectively. Thus, Ag@Zn-TSA was a kind of ideal material as highly efficient immobilization matrixes for sensitive electrochemical biosensing. In addition, this work indicated that MOF nanocomposite had a great potential for constructing wide range of sensing interface. - Highlights: • Novel Ag@Zn-TSA was used as highly efficient immobilization matrixes of Mb/glucose. • We exploited multi-function MOFs for a wide range of electrocatalytic sensing interface. • The proposed biosensors had an excellent catalytic effect on the small molecule (NO{sub 2}{sup −}, H{sub 2}O{sub 2}, glucose).

  5. Exploiting multi-function Metal-Organic Framework nanocomposite Ag@Zn-TSA as highly efficient immobilization matrixes for sensitive electrochemical biosensing

    International Nuclear Information System (INIS)

    Dong, Sheying; Zhang, Dandan; Suo, Gaochao; Wei, Wenbo; Huang, Tinglin

    2016-01-01

    A novel multi-function Metal-Organic Framework composite Ag@Zn-TSA (zinc thiosalicylate, Zn(C_7H_4O_2S), Zn-TSA) was synthesized as highly efficient immobilization matrixes of myoglobin (Mb)/glucose oxidase (GOx) for electrochemical biosensing. The electrochemical biosensors based on Ag@Zn-TSA composite and ionic liquid (IL) modified carbon paste electrode (CPE) were fabricated successfully. Furthermore, the properties of the sensors were discussed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and amperometric current-time curve, respectively. The results showed the proposed biosensors had wide linear response to hydrogen peroxide (H_2O_2) in the range of 0.3–20,000 μM, to nitrite (NO_2"−) for 1.3 μM–1660 μM and 2262 μM–1,33,000 μM, to glucose for 2.0–1022 μM, with a low detection limit of 0.08 μM for H_2O_2, 0.5 μM for NO_2"−, 0.8 μM for glucose. The values of the apparent heterogeneous electron transfer rate constant (k_s) for Mb and GOx were estimated as 2.05 s"−"1 and 2.45 s"−"1, respectively. Thus, Ag@Zn-TSA was a kind of ideal material as highly efficient immobilization matrixes for sensitive electrochemical biosensing. In addition, this work indicated that MOF nanocomposite had a great potential for constructing wide range of sensing interface. - Highlights: • Novel Ag@Zn-TSA was used as highly efficient immobilization matrixes of Mb/glucose. • We exploited multi-function MOFs for a wide range of electrocatalytic sensing interface. • The proposed biosensors had an excellent catalytic effect on the small molecule (NO_2"−, H_2O_2, glucose).

  6. Structuring an Efficient Organic Wheat Breeding Program

    Directory of Open Access Journals (Sweden)

    P. Stephen Baenziger

    2011-08-01

    Full Text Available Our long-term goal is to develop wheat cultivars that will improve the profitability and competitiveness of organic producers in Nebraska and the Northern Great Plains. Our approach is to select in early generations for highly heritable traits that are needed for both organic and conventional production (another breeding goal, followed by a targeted organic breeding effort with testing at two organic locations (each in a different ecological region beginning with the F6 generation. Yield analyses from replicated trials at two organic breeding sites and 7 conventional breeding sites from F6 through F12 nurseries revealed, using analyses of variance, biplots, and comparisons of selected lines that it is inappropriate to use data from conventional testing for making germplasm selections for organic production. Selecting and testing lines under organic production practices in different ecological regions was also needed and cultivar selections for organic production were different than those for conventional production. Modifications to this breeding protocol may include growing early generation bulks in an organic cropping system. In the future, our selection efforts should also focus on using state-of-the-art, non-transgenic breeding technologies (genomic selection, marker-assisted breeding, and high throughput phenotyping to synergistically improve organic and conventional wheat breeding.

  7. Using interlayer step-wise triplet transfer to achieve an efficient white organic light-emitting diode with high color-stability

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qi [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022 (China); Department of Electrical Engineering and Computer Sciences, College of Engineering, South Dakota State University, Brookings, South Dakota 57007 (United States); Ma, Dongge, E-mail: mdg1014@ciac.jl.cn; Ding, Junqiao; Wang, Lixiang [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022 (China); Leo, Karl [Tech. Univ. Dresden, Inst. Angew. Photophys., D-01062 Dresden (Germany); Qiao, Qiquan [Department of Electrical Engineering and Computer Sciences, College of Engineering, South Dakota State University, Brookings, South Dakota 57007 (United States); Jia, Huiping; Gnade, Bruce E. [Department of Materials Science and Engineering and Erik Jonsson School of Engineering and Computer Science, University of Texas at Dallas, Richardson, Texas 75083 (United States)

    2014-05-12

    An efficient phosphorescent white organic light emitting-diode with a red-green-blue tri-emitting-layer structure is reported. The host of the red dopant possesses a lower triplet-energy than the green dye. An interlayer step-wise triplet transfer via blue dye → green dye → red host → red dye is achieved. This mechanism allows an efficient triplet harvesting by the three dopants, thus maintaining a balanced white light and reducing energy loss. Moreover, the color stability of the device is improved significantly. The white device not only achieves a peak external quantum efficiency of 21.1 ± 0.8% and power efficiency of 37.5 ± 1.4 lm/W but shows no color shift over a wide range of voltages.

  8. Progress of OLED devices with high efficiency at high luminance

    Science.gov (United States)

    Nguyen, Carmen; Ingram, Grayson; Lu, Zhenghong

    2014-03-01

    Organic light emitting diodes (OLEDs) have progressed significantly over the last two decades. For years, OLEDs have been promoted as the next generation technology for flat panel displays and solid-state lighting due to their potential for high energy efficiency and dynamic range of colors. Although high efficiency can readily be obtained at low brightness levels, a significant decline at high brightness is commonly observed. In this report, we will review various strategies for achieving highly efficient phosphorescent OLED devices at high luminance. Specifically, we will provide details regarding the performance and general working principles behind each strategy. We will conclude by looking at how some of these strategies can be combined to produce high efficiency white OLEDs at high brightness.

  9. Unconventional, High-Efficiency Propulsors

    DEFF Research Database (Denmark)

    Andersen, Poul

    1996-01-01

    The development of ship propellers has generally been characterized by search for propellers with as high efficiency as possible and at the same time low noise and vibration levels and little or no cavitation. This search has lead to unconventional propulsors, like vane-wheel propulsors, contra-r...

  10. White organic light-emitting diodes with fluorescent tube efficiency.

    Science.gov (United States)

    Reineke, Sebastian; Lindner, Frank; Schwartz, Gregor; Seidler, Nico; Walzer, Karsten; Lüssem, Björn; Leo, Karl

    2009-05-14

    The development of white organic light-emitting diodes (OLEDs) holds great promise for the production of highly efficient large-area light sources. High internal quantum efficiencies for the conversion of electrical energy to light have been realized. Nevertheless, the overall device power efficiencies are still considerably below the 60-70 lumens per watt of fluorescent tubes, which is the current benchmark for novel light sources. Although some reports about highly power-efficient white OLEDs exist, details about structure and the measurement conditions of these structures have not been fully disclosed: the highest power efficiency reported in the scientific literature is 44 lm W(-1) (ref. 7). Here we report an improved OLED structure which reaches fluorescent tube efficiency. By combining a carefully chosen emitter layer with high-refractive-index substrates, and using a periodic outcoupling structure, we achieve a device power efficiency of 90 lm W(-1) at 1,000 candelas per square metre. This efficiency has the potential to be raised to 124 lm W(-1) if the light outcoupling can be further improved. Besides approaching internal quantum efficiency values of one, we have also focused on reducing energetic and ohmic losses that occur during electron-photon conversion. We anticipate that our results will be a starting point for further research, leading to white OLEDs having efficiencies beyond 100 lm W(-1). This could make white-light OLEDs, with their soft area light and high colour-rendering qualities, the light sources of choice for the future.

  11. Overview of Ecological Agriculture with High Efficiency

    OpenAIRE

    Huang, Guo-qin; Zhao, Qi-guo; Gong, Shao-lin; Shi, Qing-hua

    2012-01-01

    From the presentation, connotation, characteristics, principles, pattern, and technologies of ecological agriculture with high efficiency, we conduct comprehensive and systematic analysis and discussion of the theoretical and practical progress of ecological agriculture with high efficiency. (i) Ecological agriculture with high efficiency was first advanced in China in 1991. (ii) Ecological agriculture with high efficiency highlights "high efficiency", "ecology", and "combination". (iii) Ecol...

  12. High-power, high-efficiency FELs

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1989-04-01

    High power, high efficiency FELs require tapering, as the particles loose energy, so as to maintain resonance between the electromagnetic wave and the particles. They also require focusing of the particles (usually done with curved pole faces) and focusing of the electromagnetic wave (i.e. optical guiding). In addition, one must avoid transverse beam instabilities (primarily resistive wall) and longitudinal instabilities (i.e sidebands). 18 refs., 7 figs., 3 tabs

  13. Experiments on high efficiency aerosol filtration

    International Nuclear Information System (INIS)

    Mazzini, M.; Cuccuru, A.; Kunz, P.

    1977-01-01

    Research on high efficiency aerosol filtration by the Nuclear Engineering Institute of Pisa University and by CAMEN in collaboration with CNEN is outlined. HEPA filter efficiency was studied as a function of the type and size of the test aerosol, and as a function of flowrate (+-50% of the nominal value), air temperature (up to 70 0 C), relative humidity (up to 100%), and durability in a corrosive atmosphere (up to 140 hours in NaCl mist). In the selected experimental conditions these influences were appreciable but are not sufficient to be significant in industrial HEPA filter applications. Planned future research is outlined: measurement of the efficiency of two HEPA filters in series using a fixed particle size; dependence of the efficiency on air, temperatures up to 300-500 0 C; performance when subject to smoke from burning organic materials (natural rubber, neoprene, miscellaneous plastics). Such studies are relevant to possible accidental fires in a plutonium laboratory

  14. High Efficiency Room Air Conditioner

    Energy Technology Data Exchange (ETDEWEB)

    Bansal, Pradeep [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    This project was undertaken as a CRADA project between UT-Battelle and Geberal Electric Company and was funded by Department of Energy to design and develop of a high efficiency room air conditioner. A number of novel elements were investigated to improve the energy efficiency of a state-of-the-art WAC with base capacity of 10,000 BTU/h. One of the major modifications was made by downgrading its capacity from 10,000 BTU/hr to 8,000 BTU/hr by replacing the original compressor with a lower capacity (8,000 BTU/hr) but high efficiency compressor having an EER of 9.7 as compared with 9.3 of the original compressor. However, all heat exchangers from the original unit were retained to provide higher EER. The other subsequent major modifications included- (i) the AC fan motor was replaced by a brushless high efficiency ECM motor along with its fan housing, (ii) the capillary tube was replaced with a needle valve to better control the refrigerant flow and refrigerant set points, and (iii) the unit was tested with a drop-in environmentally friendly binary mixture of R32 (90% molar concentration)/R125 (10% molar concentration). The WAC was tested in the environmental chambers at ORNL as per the design rating conditions of AHAM/ASHRAE (Outdoor- 95F and 40%RH, Indoor- 80F, 51.5%RH). All these modifications resulted in enhancing the EER of the WAC by up to 25%.

  15. ON THE ECONOMIC EFFICIENCY OF ORGANIZATIONS: TOWARD A SOLUTION OF THE EFFICIENT GOVERNMENT ENTERPRISE PARADOX

    Directory of Open Access Journals (Sweden)

    Robert E. Wright

    2007-01-01

    Full Text Available The modern widely-held joint-stock corporation appears to epitomize the economically efficient large-scale organization. Some scholars observe, however, that other types of organizations, including government-owned enterprises, have also achieved high degrees of efficiency and that some joint stock corporations have been inefficient. It is here argued that the economic efficiency of organizations is largely a function of two major variables—markets tructure and incentives within the organization—and not organizational form or ownership structure per se. Case studies of two business firms: a mutual life insurer and a family-controlled publisher, and two industries: higher education and custom construction, demonstrate the importance of internal incentives and market structures to organizational economic efficiency.

  16. Comparative efficiency of high (trip super phosphate) and low (rock phosphate) grade p nutrition source enriched with organic amendment in maize crop

    International Nuclear Information System (INIS)

    Sabah, N.U.; Sarwar, G.; Tahir, M.A.

    2016-01-01

    Pakistan falls under arid to semi-arid climate and therefore, Pakistani soils are sufferer of phosphorus deficiency. Costly phosphatic commercial fertilizers and their unavailability at the time of crop demand is the burning issue in Pakistan. Under such circumstances, use of locally available rock phosphate (RP) grasps the interest of researchers now a day. Pakistan has blessed with considerable quantity of cheaper low grade RP in Abbottabad and Hazara districts of KPK province. Due to this scenario, a pot experiment was carried out to evaluate growth efficiency of maize crop by adding organic manure fortified with RP in comparison with TSP in normal soil (pHs= 8.15, ECe= 1.28 dSm-1, SAR = 4.77 mmol L-1, saturation percentage = 29% and sandy clay loam texture). The study was comprised of 7 treatments replicated three times including: T1 = Control (0 P); T2 = Recommended NK + organic material; T3 = Recommended NK + RRP; T4 = Recommended NK + RRP + OM; T5 = Recommended NK + TSP; T6 = Recommended NK + TSP + OM and T7 = N + K + TSP + 0.5 Organic manure. It was concluded that integrated use of organic amendment with RP (Local Hazara Red Rock Phosphate) and TSP proved superior as compared to their sole use on maize crop growth. A significant increase in available P concentration of the growth medium was observed due to addition of organic material along with TSP as a source of P. Addition of organic material also enhanced the soil carbon level as compared to control. It can be concluded that rock phosphate (RP) could be an effective and economic substitution for TSP when it is integrated with suitable organic amendment with specific size. (author)

  17. Photocatalytic organic transformation by layered double hydroxides: highly efficient and selective oxidation of primary aromatic amines to their imines under ambient aerobic conditions.

    Science.gov (United States)

    Yang, Xiu-Jie; Chen, Bin; Li, Xu-Bing; Zheng, Li-Qiang; Wu, Li-Zhu; Tung, Chen-Ho

    2014-06-25

    We report the first application of layered double hydroxide as a photocatalyst in the transformation of primary aromatic amines to their corresponding imines with high efficiency and selectivity by using oxygen in an air atmosphere as a terminal oxidant under light irradiation.

  18. High-efficient electron linacs

    International Nuclear Information System (INIS)

    Glavatskikh, K.V.; Zverev, B.V.; Kalyuzhnyj, V.E.; Morozov, V.L.; Nikolaev, S.V.; Plotnikov, S.N.; Sobenin, N.P.; Vovna, V.A.; Gryzlov, A.V.

    1993-01-01

    Comparison analysis of ELA on running and still waves designed for 10 MeV energy and with high efficiency is carried out. It is shown, that from the point of view of dimensions ELA with a still wave or that of a combined type is more preferable. From the point of view of impedance characteristics in any variant with application of magnetron as HF-generator it is necessary to implement special requirements to the accelerating structure if no ferrite isolation is provided in HF-channel. 3 refs., 4 figs., 1 tab

  19. Realizing Efficient Energy Harvesting from Organic Photovoltaic Cells

    Science.gov (United States)

    Zou, Yunlong

    Organic photovoltaic cells (OPVs) are emerging field of research in renewable energy. The development of OPVs in recent years has made this technology viable for many niche applications. In order to realize widespread application however, the power conversion efficiency requires further improvement. The efficiency of an OPV depends on the short-circuit current density (JSC), open-circuit voltage (VOC) and fill factor (FF). For state-of-the-art devices, JSC is mostly optimized with the application of novel low-bandgap materials and a bulk heterojunction device architecture (internal quantum efficiency approaching 100%). The remaining limiting factors are the low VOC and FF. This work focuses on overcoming these bottlenecks for improved efficiency. Temperature dependent measurements of device performance are used to examine both charge transfer and exciton ionization process in OPVs. The results permit an improved understanding of the intrinsic limit for VOC in various device architectures and provide insight on device operation. Efforts have also been directed at engineering device architecture for optimized FF, realizing a very high efficiency of 8% for vapor deposited small molecule OPVs. With collaborators, new molecules with tailored desired energy levels are being designed for further improvements in efficiency. A new type of hybrid organic-inorganic perovskite material is also included in this study. By addressing processing issues and anomalous hysteresis effects, a very high efficiency of 19.1% is achieved. Moving forward, topics including engineering film crystallinity, exploring tandem architectures and understanding degradation mechanisms will further push OPVs toward broad commercialization.

  20. High-efficiency/CRI/color stability warm white organic light-emitting diodes by incorporating ultrathin phosphorescence layers in a blue fluorescence layer

    Directory of Open Access Journals (Sweden)

    Miao Yanqin

    2018-01-01

    Full Text Available By incorporating ultrathin (80, low correlated color temperature of <3600 K, and high color stability at a wide voltage range of 5 V–9 V. These hybrid WOLEDs also reveal high forward-viewing external quantum efficiencies (EQE of 17.82%–19.34%, which are close to the theoretical value of 20%, indicating an almost complete exciton harvesting. In addition, the electroluminescence spectra of the hybrid WOLEDs can be easily improved by only changing the incorporating sequence of the ultrathin phosphorescence layers without device efficiency loss. For example, the hybrid WOLED with an incorporation sequence of ultrathin red/yellow/green phosphorescence layers exhibits an ultra-high CRI of 96 and a high EQE of 19.34%. To the best of our knowledge, this is the first WOLED with good tradeoff among device efficiency, CRI, and color stability. The introduction of ultrathin (<0.1 nm phosphorescence layers can also greatly reduce the consumption of phosphorescent emitters as well as simplify device structures and fabrication process, thus leading to low cost. Such a finding is very meaningful for the potential commercialization of hybrid WOLEDs.

  1. A robust yellow-emitting metallophosphor with electron-injection/-transporting traits for highly efficient white organic light-emitting diodes.

    Science.gov (United States)

    Zhou, Guijiang; Yang, Xiaolong; Wong, Wai-Yeung; Wang, Qi; Suo, Si; Ma, Dongge; Feng, Jikang; Wang, Lixiang

    2011-10-24

    With the aim of endowing triplet emitters in the development of organic light-emitting devices (OLEDs) with electron-injection/-transporting (EI/ET) features, the phenylsulfonyl moiety was introduced into the phenyl ring of a 2-phenylpyridine (Hppy) ligand and the yellow phosphorescent heteroleptic iridium(III) complex 1 was developed. It was shown that the SO(2)Ph unit could provide EI/ET character to 1, as indicated from both electrochemical and computational data. Complex 1 is a promising yellow-emitting material for both monochromatic OLEDs and white OLEDs (WOLEDs). The outstanding electronic traits associated with 1, coupled with careful device design, afforded very attractive electroluminescent performances for two-element WOLEDs, including a low turn-on voltage of less than 3.7 V, a maximum brightness of 48,000 cd m(-2), an external quantum efficiency of 13.0%, a luminance efficiency of 34.7 cd A(-1), and a power efficiency of 24.3 Lm W(-1). In addition, a good color rendering index (CRI) of about 74, a stable white color with a Commission Internationale de L'Eclairage (CIE(x,y)) variation of Δ(x, y) OLED research. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Zinc oxide tetrapods as efficient photocatalysts for organic pollutant degradation

    Science.gov (United States)

    Liu, Fangzhou; Leung, Yu Hang; Djurisić, Aleksandra B.; Liao, Changzhong; Shih, Kaimin

    2014-03-01

    Bisphenol A (BPA) and other organic pollutants from industrial wastewater have drawn increasing concern in the past decades regarding their environmental and biological risks, and hence developing strategies of effective degradation of BPA and other organic pollutants is imperative. Metal oxide nanostructures, in particular titanium oxide (TiO2) and zinc oxide (ZnO), have been demonstrated to exhibit efficient photodegradation of various common organic dyes. ZnO tetrapods are of special interest due to their low density of native defects which consequently lead to lower recombination losses and higher photocatalytic efficiency. Tetrapods can be obtained by relatively simple and low-cost vapor phase deposition in large quantity; the micron-scale size would also be advantageous for catalyst recovery. In this study, the photodegradation of BPA with ZnO tetrapods and TiO2 nanostructures under UV illumination were compared. The concentration of BPA dissolved in DI water was analyzed by high-performance liquid chromatography (HPLC) at specified time intervals. It was observed that the photocatalytic efficiency of ZnO tetrapods eventually surpassed Degussa P25 in free-standing form, and more than 80% of BPA was degraded after 60 min. Photodegradation of other organic dye pollutants by tetrapods and P25 were also examined. The superior photocatalytic efficiency of ZnO tetrapods for degradation of BPA and other organic dye pollutants and its correlation with the material properties were discussed.

  3. Process-based organization design and hospital efficiency.

    Science.gov (United States)

    Vera, Antonio; Kuntz, Ludwig

    2007-01-01

    The central idea of process-based organization design is that organizing a firm around core business processes leads to cost reductions and quality improvements. We investigated theoretically and empirically whether the implementation of a process-based organization design is advisable in hospitals. The data came from a database compiled by the Statistical Office of the German federal state of Rheinland-Pfalz and from a written questionnaire, which was sent to the chief executive officers (CEOs) of all 92 hospitals in this federal state. We used data envelopment analysis (DEA) to measure hospital efficiency, and factor analysis and regression analysis to test our hypothesis. Our principal finding is that a high degree of process-based organization has a moderate but significant positive effect on the efficiency of hospitals. The main implication is that hospitals should implement a process-based organization to improve their efficiency. However, to actually achieve positive effects on efficiency, it is of paramount importance to observe some implementation rules, in particular to mobilize physician participation and to create an adequate organizational culture.

  4. Natural organic matters removal efficiency by coagulation

    Science.gov (United States)

    Sapingi, Mohd Sharizal Mohd; Pishal, Munirah; Murshed, Mohamad Fared

    2017-10-01

    The presence of Natural Organic Matter (NOM) in surface water results in unwanted characteristics in terms of color, odor, and taste. NOM content reaction with free chlorine in treated water lowers the water quality further. Chlorine is added for disinfection and produces undesirable disinfection by-products (DPBs). DBPs in drinking water are carcinogenic to consumers and may promote cancerous cell development in the human body. This study was performed to compare the coagulant efficiency of aluminum sulfate (Alum) and ferric chloride (FeCl3) on NOM removal (as in UV254 absorbance) and turbidity removal under three pH conditions (pH 6, pH 7, and sample actual pH). The three sampling points for these studies were Jalan Baru River, Kerian River, and Redac Pond. Additional sampling points, such as Lubuk Buntar and a tubewell located in the Civil Engineering School, were included to observe differences in characteristics. DOC, UV absorbance, and full wavelength were tested, after which samples treated with alum were also tested to further analyze the NOM content. Based on UV254 absorbance and DOC data, specific UV value was calculated to obtain vital synopsis of the characteristics of NOM content, as well as coagulation efficiency.

  5. Highly efficient fully transparent inverted OLEDs

    Science.gov (United States)

    Meyer, J.; Winkler, T.; Hamwi, S.; Schmale, S.; Kröger, M.; Görrn, P.; Johannes, H.-H.; Riedl, T.; Lang, E.; Becker, D.; Dobbertin, T.; Kowalsky, W.

    2007-09-01

    One of the unique selling propositions of OLEDs is their potential to realize highly transparent devices over the visible spectrum. This is because organic semiconductors provide a large Stokes-Shift and low intrinsic absorption losses. Hence, new areas of applications for displays and ambient lighting become accessible, for instance, the integration of OLEDs into the windshield or the ceiling of automobiles. The main challenge in the realization of fully transparent devices is the deposition of the top electrode. ITO is commonly used as transparent bottom anode in a conventional OLED. To obtain uniform light emission over the entire viewing angle and a low series resistance, a TCO such as ITO is desirable as top contact as well. However, sputter deposition of ITO on top of organic layers causes damage induced by high energetic particles and UV radiation. We have found an efficient process to protect the organic layers against the ITO rf magnetron deposition process of ITO for an inverted OLED (IOLED). The inverted structure allows the integration of OLEDs in more powerful n-channel transistors used in active matrix backplanes. Employing the green electrophosphorescent material Ir(ppy) 3 lead to IOLED with a current efficiency of 50 cd/A and power efficiency of 24 lm/W at 100 cd/m2. The average transmittance exceeds 80 % in the visible region. The on-set voltage for light emission is lower than 3 V. In addition, by vertical stacking we achieved a very high current efficiency of more than 70 cd/A for transparent IOLED.

  6. Organic flash cycles for efficient power production

    Science.gov (United States)

    Ho, Tony; Mao, Samuel S.; Greif, Ralph

    2016-03-15

    This disclosure provides systems, methods, and apparatus related to an Organic Flash Cycle (OFC). In one aspect, a modified OFC system includes a pump, a heat exchanger, a flash evaporator, a high pressure turbine, a throttling valve, a mixer, a low pressure turbine, and a condenser. The heat exchanger is coupled to an outlet of the pump. The flash evaporator is coupled to an outlet of the heat exchanger. The high pressure turbine is coupled to a vapor outlet of the flash evaporator. The throttling valve is coupled to a liquid outlet of the flash evaporator. The mixer is coupled to an outlet of the throttling valve and to an outlet of the high pressure turbine. The low pressure turbine is coupled to an outlet of the mixer. The condenser is coupled to an outlet of the low pressure turbine and to an inlet of the pump.

  7. Efficient organic light emitting-diodes (OLEDs)

    CERN Document Server

    Chang, Yi-Lu

    2015-01-01

    Following two decades of intense research globally, the organic light-emitting diode (OLED) has steadily emerged as the ultimate display technology of choice for the coming decades. Portable active matrix OLED displays have already become prevalent, and even large-sized ultra-high definition 4K TVs are being mass-produced. More exotic applications such as wearable displays have been commercialized recently. With the burgeoning success in displays, researchers are actively bringing the technology forward into the exciting solid-state lighting market. This book presents the knowledge needed for

  8. Porous carbon derived via KOH activation of a hypercrosslinked porous organic polymer for efficient CO_2, CH_4, H_2 adsorptions and high CO_2/N_2 selectivity

    International Nuclear Information System (INIS)

    Modak, Arindam; Bhaumik, Asim

    2015-01-01

    Microporous carbon having Brunauer-Emmett-Teller (BET) surface area of 2186 m"2 g"−"1 and micropore volume of 0.85 cm"3 g"−"1 has been synthesized via KOH induced high temperature carbonization of a non-conjugated hypercrosslinked organic polymer. Owing to the templating and activation by KOH, we have succeeded in making a microporous carbon from this porous polymer and the resultant carbon material showed high uptake for CO_2 (7.6 mmol g"−"1) and CH_4 (2.4 mmol g"−"1) at 1 atm, 273 K together with very good selectivity for the CO_2/N_2 (30.2) separation. Furthermore, low pressure (1 atm) H_2 (2.6 wt%, 77 K) and water uptake (57.4 wt%, 298 K) ability of this polymer derived porous activated carbon is noteworthy. - Graphical abstract: Microporous carbon with BET surface area of 2186 m"2 g"−"1 has been synthesized via KOH activation of a porous organic polymer and it showed high uptake for CO_2 (7.6 mmol g"−"1), CH_4 (2.4 mmol g"−"1) and H_2 (2.6 wt%) at 1 atm together with very good selectivity for CO_2. - Highlights: • Porous carbon from hypercrosslinked organic polymer. • KOH activated carbon with BET surface area 2186 m"2 g"−"1. • High CO2 uptake (7.6 mmol g"−"1) and CO_2/N_2 selectivity (30.2). • Porous carbon also showed high H_2 (2.6 wt%) and H_2O (57.4 wt%) uptakes.

  9. Key factors of efficient organization management

    OpenAIRE

    Firsankov, I. E.; Фирсанков, И. Е.

    2014-01-01

    Issues of efficiency of organization management are examined in the article. Aggressive competition between companies; what’s the difference between manager and leader; who is a leader; personal qualities of strong charismatic leaders etc. Particular attention is paid to the question of possibility to become a leader or to be born a leader. В статье рассмотрены основные черты настоящего лидера, затронута тема различия между лидером и менеджером, а также освещён вопрос о том, можно ли стать...

  10. Organic-Inorganic Composites of Semiconductor Nanocrystals for Efficient Excitonics.

    Science.gov (United States)

    Guzelturk, Burak; Demir, Hilmi Volkan

    2015-06-18

    Nanocomposites of colloidal semiconductor nanocrystals integrated into conjugated polymers are the key to soft-material hybrid optoelectronics, combining advantages of both plastics and particles. Synergic combination of the favorable properties in the hybrids of colloidal nanocrystals and conjugated polymers offers enhanced performance and new functionalities in light-generation and light-harvesting applications, where controlling and mastering the excitonic interactions at the nanoscale are essential. In this Perspective, we highlight and critically consider the excitonic interactions in the organic-inorganic nanocomposites to achieve highly efficient exciton transfer through rational design of the nanocomposites. The use of strong excitonic interactions in optoelectronic devices can trigger efficiency breakthroughs in hybrid optoelectronics.

  11. Towards highly efficient water photoelectrolysis

    Science.gov (United States)

    Elavambedu Prakasam, Haripriya

    ethylene glycol resulted in remarkable growth characteristics of titania nanotube arrays, hexagonal closed packed up to 1 mm in length, with tube aspect ratios of approximately 10,000. For the first time, complete anodization of the starting titanium foil has been demonstrated resulting in back to back nanotube array membranes ranging from 360 mum--1 mm in length. The nanotubes exhibited growth rates of up to 15 mum/hr. A detailed study on the factors affecting the growth rate and nanotube dimensions is presented. It is suggested that faster high field ionic conduction through a thinner barrier layer is responsible for the higher growth rates observed in electrolytes containing ethylene glycol. Methods to fabricate free standing, titania nanotube array membranes ranging in thickness from 50 microm--1000 mum has also been an outcome of this dissertation. In an effort to combine the charge transport properties of titania with the light absorption properties of iron (III) oxide, films comprised of vertically oriented Ti-Fe-O nanotube arrays on FTO coated glass substrates have been successfully synthesized in ethylene glycol electrolytes. Depending upon the Fe content the bandgap of the resulting films varied from about 3.26 to 2.17 eV. The Ti-Fe oxide nanotube array films demonstrated a photocurrent of 2 mA/cm2 under global AM 1.5 illumination with a 1.2% (two-electrode) photoconversion efficiency, demonstrating a sustained, time-energy normalized hydrogen evolution rate by water splitting of 7.1 mL/W·hr in a 1 M KOH solution with a platinum counter electrode under an applied bias of 0.7 V. The Ti-Fe-O material architecture demonstrates properties useful for hydrogen generation by water photoelectrolysis and, more importantly, this dissertation demonstrates that the general nanotube-array synthesis technique can be extended to other ternary oxide compositions of interest for water photoelectrolysis.

  12. Development of photocatalysts for selective and efficient organic transformations.

    Science.gov (United States)

    Munir, Shamsa; Dionysiou, Dionysios D; Khan, Sher Bahadar; Shah, Syed Mujtaba; Adhikari, Bimalendu; Shah, Afzal

    2015-07-01

    One of the main goals of organic chemists is to find easy, environmentally friendly, and cost effective methods for the synthesis of industrially important compounds. Photocatalysts have brought revolution in this regard as they make use of unlimited source of energy (the solar light) to carry out the synthesis of organic compounds having otherwise complex synthetic procedures. However, selectivity of the products has been a major issue since the beginning of photocatalysis. The present article encompasses state of the art accomplishments in harvesting light energy for selective organic transformations using photocatalysts. Several approaches for the development of photocatalysts for selective organic conversions have been critically discussed with the objective of developing efficient, selective, environmental friendly and high yield photocatalytic methodologies. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. High mobility emissive organic semiconductor

    Science.gov (United States)

    Liu, Jie; Zhang, Hantang; Dong, Huanli; Meng, Lingqiang; Jiang, Longfeng; Jiang, Lang; Wang, Ying; Yu, Junsheng; Sun, Yanming; Hu, Wenping; Heeger, Alan J.

    2015-01-01

    The integration of high charge carrier mobility and high luminescence in an organic semiconductor is challenging. However, there is need of such materials for organic light-emitting transistors and organic electrically pumped lasers. Here we show a novel organic semiconductor, 2,6-diphenylanthracene (DPA), which exhibits not only high emission with single crystal absolute florescence quantum yield of 41.2% but also high charge carrier mobility with single crystal mobility of 34 cm2 V−1 s−1. Organic light-emitting diodes (OLEDs) based on DPA give pure blue emission with brightness up to 6,627 cd m−2 and turn-on voltage of 2.8 V. 2,6-Diphenylanthracene OLED arrays are successfully driven by DPA field-effect transistor arrays, demonstrating that DPA is a high mobility emissive organic semiconductor with potential in organic optoelectronics. PMID:26620323

  14. Facile fabrication of Ag3VO4/attapulgite composites for highly efficient visible light-driven photodegradation towards organic dyes and tetracycline hydrochloride

    Science.gov (United States)

    Luo, Yuting; Luo, Jie; Duan, Guorong; Liu, Xiaoheng

    2017-12-01

    An efficient one-dimensional attapulgite (ATP)-based photocatalyst, Ag3VO4/ATP nanocomposite, was fabricated by a facile deposition precipitation method with well-dispersed Ag3VO4 nanoparticles anchored on the surface of natural ATP fibers. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and UV-visible diffused reflectance spectroscopy (UV-vis DRS) were employed to investigate the morphologies, structure, and optical property of the prepared photocatalysts. The photocatalytic experiments indicated that the Ag3VO4/ATP nanocomposites exhibited enhanced visible light-driven photocatalytic activity towards the degradation of rhodamine B (RhB), methyl orange (MO), and tetracycline hydrochloride (TCH), of which the 20 wt% Ag3VO4/ATP sample showed superb photocatalytic performance. As demonstrated by N2 adsorption-desorption, photocurrent measurements, electrochemical impedance spectroscopy (EIS), and photoluminescence (PL) spectra analyses, the improved photocatalytic activity arose from the enlarged surface area, the facilitated charge transfer, and the suppressed recombination of photogenerated charge carriers in Ag3VO4/ATP system. Furthermore, radical scavengers trapping experiments and recycling tests were also conducted. This work gives a new insight into fabrication of highly efficient, stable, and cost-effective visible light-driven photocatalyst for practical application in wastewater treatment and environmental remediation.

  15. HIGH-EFFICIENCY INFRARED RECEIVER

    Directory of Open Access Journals (Sweden)

    A. K. Esman

    2016-01-01

    Full Text Available Recent research and development show promising use of high-performance solid-state receivers of the electromagnetic radiation. These receivers are based on the low-barrier Schottky diodes. The approach to the design of the receivers on the basis of delta-doped low-barrier Schottky diodes with beam leads without bias is especially actively developing because for uncooled receivers of the microwave radiation these diodes have virtually no competition. The purpose of this work is to improve the main parameters and characteristics that determine the practical relevance of the receivers of mid-infrared electromagnetic radiation at the operating room temperature by modifying the electrodes configuration of the diode and optimizing the distance between them. Proposed original design solution of the integrated receiver of mid-infrared radiation on the basis of the low-barrier Schottky diodes with beam leads allows to effectively adjust its main parameters and characteristics. Simulation of the electromagnetic characteristics of the proposed receiver by using the software package HFSS with the basic algorithm of a finite element method which implemented to calculate the behavior of electromagnetic fields on an arbitrary geometry with a predetermined material properties have shown that when the inner parts of the electrodes of the low-barrier Schottky diode is performed in the concentric elliptical convex-concave shape, it can be reduce the reflection losses to -57.75 dB and the standing wave ratio to 1.003 while increasing the directivity up to 23 at a wavelength of 6.09 μm. At this time, the rounded radii of the inner parts of the anode and cathode electrodes are equal 212 nm and 318 nm respectively and the gap setting between them is 106 nm. These parameters will improve the efficiency of the developed infrared optical-promising and electronic equipment for various purposes intended for work in the mid-infrared wavelength range. 

  16. High-efficiency wind turbine

    Science.gov (United States)

    Hein, L. A.; Myers, W. N.

    1980-01-01

    Vertical axis wind turbine incorporates several unique features to extract more energy from wind increasing efficiency 20% over conventional propeller driven units. System also features devices that utilize solar energy or chimney effluents during periods of no wind.

  17. High efficiency, long life terrestrial solar panel

    Science.gov (United States)

    Chao, T.; Khemthong, S.; Ling, R.; Olah, S.

    1977-01-01

    The design of a high efficiency, long life terrestrial module was completed. It utilized 256 rectangular, high efficiency solar cells to achieve high packing density and electrical output. Tooling for the fabrication of solar cells was in house and evaluation of the cell performance was begun. Based on the power output analysis, the goal of a 13% efficiency module was achievable.

  18. High efficiency turbine blade coatings

    Energy Technology Data Exchange (ETDEWEB)

    Youchison, Dennis L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gallis, Michail A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-06-01

    The development of advanced thermal barrier coatings (TBCs) of yttria stabilized zirconia (YSZ) that exhibit lower thermal conductivity through better control of electron beam - physical vapor deposition (EB-PVD) processing is of prime interest to both the aerospace and power industries. This report summarizes the work performed under a two-year Lab-Directed Research and Development (LDRD) project (38664) to produce lower thermal conductivity, graded-layer thermal barrier coatings for turbine blades in an effort to increase the efficiency of high temperature gas turbines. This project was sponsored by the Nuclear Fuel Cycle Investment Area. Therefore, particular importance was given to the processing of the large blades required for industrial gas turbines proposed for use in the Brayton cycle of nuclear plants powered by high temperature gas-cooled reactors (HTGRs). During this modest (~1 full-time equivalent (FTE)) project, the processing technology was developed to create graded TBCs by coupling ion beam-assisted deposition (IBAD) with substrate pivoting in the alumina-YSZ system. The Electron Beam - 1200 kW (EB-1200) PVD system was used to deposit a variety of TBC coatings with micron layered microstructures and reduced thermal conductivity below 1.5 W/m.K. The use of IBAD produced fully stoichiometric coatings at a reduced substrate temperature of 600°C and a reduced oxygen background pressure of 0.1 Pa. IBAD was also used to successfully demonstrate the transitioning of amorphous PVD-deposited alumina to the -phase alumina required as an oxygen diffusion barrier and for good adhesion to the substrate Ni2Al3 bondcoat. This process replaces the time consuming thermally grown oxide formation required before the YSZ deposition. In addition to the process technology, Direct Simulation Monte Carlo plume modeling and spectroscopic characterization of the PVD plumes were performed. The project consisted of five tasks. These included the

  19. Ternary Organic Solar Cells with Coumarin7 as the Donor Exhibiting Greater Than 10% Power Conversion Efficiency and a High Fill Factor of 75.

    Science.gov (United States)

    Chen, Xin-Wei; Tao, Si-Lu; Fan, Cong; Chen, Dong-Cheng; Zhou, Ling; Lin, Hui; Zheng, Cai-Jun; Su, Shi-Jian

    2017-09-06

    Ternary bulk heterojunction (BHJ) is a brilliant photovoltaic technology for improving the performance of organic solar cells (OSCs), because the light absorption range can be significantly extended by using multiple donors or acceptor materials. In this paper, coumarin7 (C7), a small organic molecule typical led used in organic light-emitting diodes, was initially exploited as second electron-donor component in ternary bulk heterojunction OSCs along with conventional blend system spolythieno[3,4-b]-thiophene/benzodithiophene(PTB7) and [6,6]-phenyl-C71 -butyric acid methyl(PC 71 BM). A champion PCE value of 10.28% was realized in the ternary OSCs when incorporated with 10 wt % C7 doping ratio in the donors, corresponding to about 35% enhancement compared with the PTB7:PC 71 BM-based OSCs, a high fill factor (FF) of 75.03%, a short-circuit currentdensity (J sc ) of 18.72 mA cm -2 and an open-circuit voltage (V oc ) of 0.73 V. The enhanced performance of the ternary OSCs can be attributed to the simultaneous improvement of the FF and the J sc . In addition to extended light absorption, a perfect nanofiber filament active layer morphology is obtained due to the good compatibility between C7 and PTB7, which facilitates the balance of charge transportation and the suppression of charge recombination. This investigation suggests that coumarin derivatives, which have completely different structure with polymer donors, can also be used to fabricate ternary solar cells and have the potential applications to obtain amazing performance after further device engineering and optimization.

  20. Interface engineering for efficient fullerene-free organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Shivanna, Ravichandran; Narayan, K. S., E-mail: rajaram@jncasr.ac.in, E-mail: narayan@jncasr.ac.in [Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India); Rajaram, Sridhar, E-mail: rajaram@jncasr.ac.in, E-mail: narayan@jncasr.ac.in [International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India)

    2015-03-23

    We demonstrate the role of zinc oxide (ZnO) morphology and addition of an acceptor interlayer to achieve high efficiency fullerene-free bulk heterojunction inverted organic solar cells. Nanopatterning of the ZnO buffer layer enhances the effective light absorption in the active layer, and the insertion of a twisted perylene acceptor layer planarizes and decreases the electron extraction barrier. Along with an increase in current homogeneity, the reduced work function difference and selective transport of electrons prevent the accumulation of charges and decrease the electron-hole recombination at the interface. These factors enable an overall increase of efficiency to 4.6%, which is significant for a fullerene-free solution-processed organic solar cell.

  1. Efficiency optimization of green phosphorescent organic light-emitting device

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jung Soo; Jeon, Woo Sik; Yu, Jae Hyung [Department of Information Display, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701 (Korea, Republic of); Pode, Ramchandra, E-mail: rbpode@khu.ac.k [Department of Physics, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701 (Korea, Republic of); Kwon, Jang Hyuk, E-mail: jhkwon@khu.ac.k [Department of Information Display, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701 (Korea, Republic of)

    2011-03-01

    Using a narrow band gap host of bis[2-(2-hydroxyphenyl)-pyridine]beryllium (Bepp{sub 2}) and green phosphorescent Ir(ppy){sub 3} [fac-tris(2-phenylpyridine) iridium III] guest concentration as low as 2%, high efficiency phosphorescent organic light-emitting diode (PHOLED) is realized. Current and power efficiencies of 62.5 cd/A (max.), 51.0 lm/W (max.), and external quantum efficiency (max.) of 19.8% are reported in this green PHOLED. A low current efficiency roll-off value of 10% over the brightness of 10,000 cd/m{sup 2} is noticed in this Bepp{sub 2} single host device. Such a high efficiency is obtained by the optimization of the doping concentration with the knowledge of the hole trapping and the emission zone situations in this host-guest system. It is suggested that the reported device performance is suitable for applications in high brightness displays and lighting.

  2. Multiscale approaches to high efficiency photovoltaics

    Directory of Open Access Journals (Sweden)

    Connolly James Patrick

    2016-01-01

    Full Text Available While renewable energies are achieving parity around the globe, efforts to reach higher solar cell efficiencies becomes ever more difficult as they approach the limiting efficiency. The so-called third generation concepts attempt to break this limit through a combination of novel physical processes and new materials and concepts in organic and inorganic systems. Some examples of semi-empirical modelling in the field are reviewed, in particular for multispectral solar cells on silicon (French ANR project MultiSolSi. Their achievements are outlined, and the limits of these approaches shown. This introduces the main topic of this contribution, which is the use of multiscale experimental and theoretical techniques to go beyond the semi-empirical understanding of these systems. This approach has already led to great advances at modelling which have led to modelling software, which is widely known. Yet, a survey of the topic reveals a fragmentation of efforts across disciplines, firstly, such as organic and inorganic fields, but also between the high efficiency concepts such as hot carrier cells and intermediate band concepts. We show how this obstacle to the resolution of practical research obstacles may be lifted by inter-disciplinary cooperation across length scales, and across experimental and theoretical fields, and finally across materials systems. We present a European COST Action “MultiscaleSolar” kicking off in early 2015, which brings together experimental and theoretical partners in order to develop multiscale research in organic and inorganic materials. The goal of this defragmentation and interdisciplinary collaboration is to develop understanding across length scales, which will enable the full potential of third generation concepts to be evaluated in practise, for societal and industrial applications.

  3. High altitude organic gold

    DEFF Research Database (Denmark)

    Pouliot, Mariève; Pyakurel, Dipesh; Smith-Hall, Carsten

    2018-01-01

    Ethnopharmacological relevance Ophiocordyceps sinensis (Berk.) G.H.Sung, J.M.Sung, Hywel-Jones & Spatafora, a high altitude Himalayan fungus-caterpillar product found in alpine meadows in China, Bhutan, Nepal, and India, has been used in the Traditional Chinese Medicine system for over 2000 years...

  4. High efficiency motor selection handbook

    Science.gov (United States)

    McCoy, Gilbert A.; Litman, Todd; Douglass, John G.

    1990-10-01

    Substantial reductions in energy and operational costs can be achieved through the use of energy-efficient electric motors. A handbook was compiled to help industry identify opportunities for cost-effective application of these motors. It covers the economic and operational factors to be considered when motor purchase decisions are being made. Its audience includes plant managers, plant engineers, and others interested in energy management or preventative maintenance programs.

  5. Efficient removal of H2S at high temperature using the ionic liquid solutions of [C4mim]3PMo12O40-An organic polyoxometalate.

    Science.gov (United States)

    Ma, Yunqian; Liu, Xinpeng; Wang, Rui

    2017-06-05

    An innovative approach to H 2 S capture and sulfur recovery via liquid redox at high temperature has been developed using [C 4 mim] 3 PMo 12 O 40 at temperatures ranging from 80 to 180°C, which is superior to the conventional water-based system with an upper limit of working temperature normally below 60°C. The ionic liquids used as solvents include [C 4 mim]Cl, [C 4 mim]BF 4 , [C 4 mim]PF 6 and [C 4 mim]NTf 2 . Microscopic observation and turbidity measurement were used to investigate the dissolution of [C 4 mim] 3 PMo 12 O 40 in the ionic liquids. Stabilization energy between H 2 S and the anion of ionic liquid as well as H 2 O was calculated to illustrate the interaction between H 2 S and the solvents. The cavity theory can be adopted to illustrate the mechanism for H 2 S absorption: the Cl - ion with small radius can be incorporated into the cavities of [C 4 mim] 3 PMo 12 O 40 , and interact with H 2 S strongly. The underlying mechanism for sulfur formation is the redox reaction between H 2 S and PMo 12 O 40 3- . H 2 S can be oxidized to elemental sulfur and Mo 6+ is partly reduced during absorption, according to UV-vis and FTIR spectra. The [C 4 mim] 3 PMo 12 O 40 -[C 4 mim]Cl after reaction can be readily regenerated by air and thus enabling its efficient and repeatitive use. The absorbent of [C 4 mim] 3 PMo 12 O 40 -ionic liquid system provides a new approach for wet oxidation desulfurization at high temperature. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Designing High-Trust Organizations

    DEFF Research Database (Denmark)

    Jagd, Søren

    The specific problem considered in this paper is what are the key issues to consider for managers involved in designing high-trust organizations, a design problem still not properly explored. This paper intends to take the first step in filling this lacuna. In the paper, I first present...... the existing management and research literature on building high-trust organizations. Then I explore Alan Fox’s (1974) analysis of low-trust vs. high-trust dynamics which, I argue, may serve as a theoretically stronger basis for understanding the issues management have to consider when designing hightrust...... organizations...

  7. High efficiency focus neutron generator

    Science.gov (United States)

    Sadeghi, H.; Amrollahi, R.; Zare, M.; Fazelpour, S.

    2017-12-01

    In the present paper, the new idea to increase the neutron yield of plasma focus devices is investigated and the results are presented. Based on many studies, more than 90% of neutrons in plasma focus devices were produced by beam target interactions and only 10% of them were due to thermonuclear reactions. While propounding the new idea, the number of collisions between deuteron ions and deuterium gas atoms were increased remarkably well. The COMSOL Multiphysics 5.2 was used to study the given idea in the known 28 plasma focus devices. In this circumstance, the neutron yield of this system was also obtained and reported. Finally, it was found that in the ENEA device with 1 Hz working frequency, 1.1 × 109 and 1.1 × 1011 neutrons per second were produced by D-D and D-T reactions, respectively. In addition, in the NX2 device with 16 Hz working frequency, 1.34 × 1010 and 1.34 × 1012 neutrons per second were produced by D-D and D-T reactions, respectively. The results show that with regards to the sizes and energy of these devices, they can be used as the efficient neutron generators.

  8. Towards low cost, efficient and stable organic photovoltaic modules

    Energy Technology Data Exchange (ETDEWEB)

    Andriessen, R. [Holst Centre - Solliance, PO Box 8550, 5605 KN Eindhoven (Netherlands); Kroon, J.M. [ECN - Solliance, Petten (Netherlands); Aernouts, T. [Imec, Solliance, Kapeldreef 75, B-3001 Leuven (Belgium); Janssen, R. [Eindhoven University of Technology, Solliance, Eindhoven (Netherlands)

    2012-09-15

    This article describes how the Solliance Organic PhotoVoltaics (OPV) shared research Program addresses efficiency, lifetime and production costs for (near) future OPV applications. The balance of these three parameters depends of the envisaged application, but at the end, OPV should be able to compete somehow with Si PV in the future. Efficiency improvements are realized by developing new materials, by exploring and optimizing new device structures and novel interconnection technologies. Lifetime improvements are realized by using stabilized device stacks and materials and by applying high end flexible barriers. Production cost control is done by using a home made Cost of Ownership tool which guides towards the use of low-cost materials and processes.

  9. Highly efficient red phosphorescent Ir(III) complexes for organic light- emitting diodes based on aryl(6-arylpyridin-3-yl)methanone ligands

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hyun Ju; Lee, Kum Hee [Department of Chemistry, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Lee, Seok Jae; Seo, Ji Hyun [Department of Information Display, Hongik University, Seoul 121-791 (Korea, Republic of); Kim, Young Kwan, E-mail: kimyk@wow.hongik.ac.kr [Department of Information Display, Hongik University, Seoul 121-791 (Korea, Republic of); Yoon, Seung Soo, E-mail: ssyoon@skku.edu [Department of Chemistry, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of)

    2011-07-29

    A series of phosphorescent Ir(III) complexes 1-4 were synthesized based on aryl(6-arylpyridin-3-yl)methanone ligands, and their photophysical and electroluminescent properties were characterized. Multilayer devices with the configuration, Indium tin oxide/4,4',4''-tris(N-(naphthalene-2-yl)-N-phenyl-amino)triphenylamine (60 nm)/4,4'-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (20 nm)/Ir(III) complexes doped in N,N'-dicarbazolyl-4,4'-biphenyl (30 nm, 8%)/2,9-dimethyl-4,7-diphenyl-phenathroline (10 nm)/tris(8-hydroxyquinoline)-aluminum (20 nm)/lithium quinolate (2 nm)/ Al (100 nm), were fabricated. Among these, the device employing complex 2 as a dopant exhibited efficient red emission with a maximum luminance, luminous efficiency, power efficiency and quantum efficiency of 16200 cd/m{sup 2} at 14.0 V, 12.20 cd/A at 20 mA/cm{sup 2}, 4.26 lm/W and 9.26% at 20 mA/cm{sup 2}, respectively, with Commission Internationale de l'Enclairage coordinates of (0.63, 0.37) at 12.0 V.

  10. Mechanism for efficient photoinduced charge separation at disordered organic heterointerfaces

    Energy Technology Data Exchange (ETDEWEB)

    Eersel, Harm van; Janssen, Rene A.J.; Kemerink, Martijn [Eindhoven University of Technology, Department of Applied Physics, Eindhoven (Netherlands)

    2012-07-10

    Despite the poor screening of the Coulomb potential in organic semiconductors, excitons can dissociate efficiently into free charges at a donor-acceptor heterojunction, leading to application in organic solar cells. A kinetic Monte Carlo model that explains this high efficiency as a two-step process is presented. Driven by the band offset between donor and acceptor, one of the carriers first hops across the interface, forming a charge transfer (CT) complex. Since the electron and hole forming the CT complex have typically not relaxed within the disorder-broadened density of states (DOS), their remaining binding energy can be overcome by further relaxation in the DOS. The model only contains parameters that are determined from independent measurements and predicts dissociation yields in excess of 90% for a prototypical heterojunction. Field, temperature, and band offset dependencies are investigated and found to be in agreement with earlier experiments. Whereas the investigated heterojunctions have substantial energy losses associated with the dissociation process, these results suggest that it is possible to reach high dissociation yields at low energy loss. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Solution-processed highly conductive PEDOT:PSS/AgNW/GO transparent film for efficient organic-Si hybrid solar cells.

    Science.gov (United States)

    Xu, Qiaojing; Song, Tao; Cui, Wei; Liu, Yuqiang; Xu, Weidong; Lee, Shuit-Tong; Sun, Baoquan

    2015-02-11

    Hybrid solar cells based on n-Si/poly(3,4-ethylenedioxythiophene):poly(styrene- sulfonate) (PEDOT:PSS) heterojunction promise to be a low cost photovoltaic technology by using simple device structure and easy fabrication process. However, due to the low conductivity of PEDOT:PSS, a metal grid deposited by vacuum evaporation method is still required to enhance the charge collection efficiency, which complicates the device fabrication process. Here, a solution-processed graphene oxide (GO)-welded silver nanowires (AgNWs) transparent conductive electrode (TCE) was employed to replace the vacuum deposited metal grid. A unique "sandwich" structure was developed by embedding an AgNW network between PEDOT:PSS and GO with a figure-of-merit of 8.6×10(-3) Ω(-1), which was even higher than that of sputtered indium tin oxide electrode (6.6×10(-3) Ω(-1)). A champion power conversion efficiency of 13.3% was achieved, because of the decreased series resistance of the TCEs as well as the enhanced built-in potential (Vbi) in the hybrid solar cells. The TCEs were obtained by facile low-temperature solution process method, which was compatible with cost-effective mass production technology.

  12. Enhanced Power Conversion Efficiency of P3HT : PC71BM Bulk Heterojunction Polymer Solar Cells by Doping a High-Mobility Small Organic Molecule

    Directory of Open Access Journals (Sweden)

    Hanyu Wang

    2015-01-01

    Full Text Available The effect of molecular doping with TIPS-pentacene on the photovoltaic performance of polymer solar cells (PSCs with a structure of ITO/ZnO/poly(3-hexylthiophene-2,5-diyl (P3HT : [6,6]-phenyl C71-butyric acid methyl ester (PC71BM : TIPS-pentacene/MoOx/Ag was systematically investigated by adjusting TIPS-pentacene doping ratios ranged from 0.3 to 1.2 wt%. The device with 0.6 wt% TIPS-pentacene exhibited the enhanced short-circuit current and fill factor by 1.23 mA/cm2 and 7.8%, respectively, resulting in a maximum power conversion efficiency of 4.13%, which is one-third higher than that of the undoped one. The photovoltaic performance improvement was mainly due to the balanced charge carrier mobility, enhanced crystallinity, and matched cascade energy level alignment in TIPS-pentacene doped active layer, resulting in the efficient charge separation, transport, and collection.

  13. Self-organized InGaAs/GaAs quantum dot arrays for use in high-efficiency intermediate-band solar cells

    International Nuclear Information System (INIS)

    Shoji, Yasushi; Okada, Yoshitaka; Akimoto, Katsuhiro

    2013-01-01

    We have investigated the material properties of multi-layer stacked InGaAs/GaAs quantum dots (QDs) grown on GaAs (311)B substrates. Symmetrical lens-shaped QDs were observed along [01-1], while their shape was asymmetric along the [-233] azimuth surrounded by two different dominant facets. Further, QDs were vertically aligned in the [311] direction when viewed along [01-1], while the alignment was inclined with respect to the growth direction when viewed along [-233]. The inclination angle of vertical alignment QDs became monotonically smaller from 22° to 2° with decreasing spacer layer thickness from 40 to 20 nm. Time-resolved photoluminescence measurements showed that multi-stacked QDs with thinner spacer layers resulted in increased PL decay times. We believe that an electronically coupled QD state or an intermediate band was formed, if the spacer layer thickness was reduced below 20 nm in this material system. For an InGaAs/GaAs QD solar cell grown on a GaAs (311)B substrate, the external quantum efficiency showed a clear increase in the longer wavelength range due to an additive contribution from the QD layers. Furthermore, photocurrent production due to two-step absorption of sub-bandgap photons, which is a key element that is necessary to be demonstrated for an increase in the efficiency of a single-junction solar cell beyond the Shockley-Queisser, was observed at room temperature under one sun condition. This photocurrent production increased under a forward-bias regime as the QDs were partially filled with carriers under the bias.

  14. Tris(2-(1 H -pyrazol-1-yl)pyridine)cobalt(III) as p-Type Dopant for Organic Semiconductors and Its Application in Highly Efficient Solid-State Dye-Sensitized Solar Cells

    KAUST Repository

    Burschka, Julian

    2011-11-16

    Chemical doping is an important strategy to alter the charge-transport properties of both molecular and polymeric organic semiconductors that find widespread application in organic electronic devices. We report on the use of a new class of Co(III) complexes as p-type dopants for triarylamine-based hole conductors such as spiro-MeOTAD and their application in solid-state dye-sensitized solar cells (ssDSCs). We show that the proposed compounds fulfill the requirements for this application and that the discussed strategy is promising for tuning the conductivity of spiro-MeOTAD in ssDSCs, without having to rely on the commonly employed photo-doping. By using a recently developed high molar extinction coefficient organic D-π-A sensitizer and p-doped spiro-MeOTAD as hole conductor, we achieved a record power conversion efficiency of 7.2%, measured under standard solar conditions (AM1.5G, 100 mW cm -2). We expect these promising new dopants to find widespread applications in organic electronics in general and photovoltaics in particular. © 2011 American Chemical Society.

  15. High Intensity Organic Light-emitting Diodes

    Science.gov (United States)

    Qi, Xiangfei

    This thesis is dedicated to the fabrication, modeling, and characterization to achieve high efficiency organic light-emitting diodes (OLEDs) for illumination applications. Compared to conventional lighting sources, OLEDs enabled the direct conversion of electrical energy into light emission and have intrigued the world's lighting designers with the long-lasting, highly efficient illumination. We begin with a brief overview of organic technology, from basic organic semiconductor physics, to its application in optoelectronics, i.e. light-emitting diodes, photovoltaics, photodetectors and thin-film transistors. Due to the importance of phosphorescent materials, we will focus on the photophysics of metal complexes that is central to high efficiency OLED technology, followed by a transient study to examine the radiative decay dynamics in a series of phosphorescent platinum binuclear complexes. The major theme of this thesis is the design and optimization of a novel architecture where individual red, green and blue phosphorescent OLEDs are vertically stacked and electrically interconnected by the compound charge generation layers. We modeled carrier generation from the metal-oxide/doped organic interface based on a thermally assisted tunneling mechanism. The model provides insights to the optimization of a stacked OLED from both electrical and optical point of view. To realize the high intensity white lighting source, the efficient removal of heat is of a particular concern, especially in large-area devices. A fundamental transfer matrix analysis is introduced to predict the thermal properties in the devices. The analysis employs Laplace transforms to determine the response of the system to the combined effects of conduction, convection, and radiation. This perspective of constructing transmission matrices greatly facilitates the calculation of transient coupled heat transfer in a general multi-layer composite. It converts differential equations to algebraic forms, and

  16. Efficient cascade multiple heterojunction organic solar cells with inverted structure

    Science.gov (United States)

    Guo, Tingting; Li, Mingtao; Qiao, Zhenfang; Yu, Leiming; Zhao, Jianhong; Feng, Nianjun; Shi, Peiguang; Wang, Xiaoyan; Pu, Xiaoyun; Wang, Hai

    2018-05-01

    In this work, we demonstrate an efficient cascade multiple heterojunction organic solar cell with inverted structure. By using two donor materials, poly(3-hexylthiosphene) (P3HT) and titanyl phthalocyanine (TiOPc), as well as two acceptor materials, [6,6]-phenyl C61 butyric acid methyl ester (PCBM) and C60, the cascade multiple heterojunctions of P3HT:PCBM/TiOPc:C60/C60 have been constructed. Applying the optimized inverted configuration of FTO/Zinc Tin Oxide (ZTO)/C60 (30 nm)/TiOPc:C60 (1:1.5, 25 nm)/P3HT:PCBM (1:0.8, 100 nm)/MoO3 (4 nm)/Ag, the considerably enhanced open circuit voltage (VOC) and short circuit current (JSC) can be harvested together, and the power conversion efficiency (PCE) is three times higher than that of the control cell with conventional structure. The significant improvements of the inverted cell are mostly due to the broadened spectral absorption and high efficient multi-interface exciton dissociation in the cascade multiple heterojunctions, indicating that the optimized cascade heterojunctions match the inverted structure well.

  17. Pathways to a New Efficiency Regime for Organic Solar Cells

    NARCIS (Netherlands)

    Koster, L. Jan Anton; Shaheen, Sean E.; Hummelen, Jan C.

    2012-01-01

    Three different theoretical approaches are presented to identify pathways to organic solar cells with power conversion efficiencies in excess of 20%. A radiation limit for organic solar cells is introduced that elucidates the role of charge-transfer (CT) state absorption. Provided this CT action is

  18. Characterization of Organic Anion Transporter 2 (SLC22A7): A Highly Efficient Transporter for Creatinine and Species-Dependent Renal Tubular Expression.

    Science.gov (United States)

    Shen, Hong; Liu, Tongtong; Morse, Bridget L; Zhao, Yue; Zhang, Yueping; Qiu, Xi; Chen, Cliff; Lewin, Anne C; Wang, Xi-Tao; Liu, Guowen; Christopher, Lisa J; Marathe, Punit; Lai, Yurong

    2015-07-01

    The contribution of organic anion transporter OAT2 (SLC22A7) to the renal tubular secretion of creatinine and its exact localization in the kidney are reportedly controversial. In the present investigation, the transport of creatinine was assessed in human embryonic kidney (HEK) cells that stably expressed human OAT2 (OAT2-HEK) and isolated human renal proximal tubule cells (HRPTCs). The tubular localization of OAT2 in human, monkey, and rat kidney was characterized. The overexpression of OAT2 significantly enhanced the uptake of creatinine in OAT2-HEK cells. Under physiologic conditions (creatinine concentrations of 41.2 and 123.5 µM), the initial rate of OAT2-mediated creatinine transport was approximately 11-, 80-, and 80-fold higher than OCT2, multidrug and toxin extrusion protein (MATE)1, and MATE2K, respectively, resulting in approximately 37-, 1850-, and 80-fold increase of the intrinsic transport clearance when normalized to the transporter protein concentrations. Creatinine intracellular uptake and transcellular transport in HRPTCs were decreased in the presence of 50 µM bromosulfophthalein and 100 µM indomethacin, which inhibited OAT2 more potently than other known creatinine transporters, OCT2 and multidrug and toxin extrusion proteins MATE1 and MATE2K (IC50: 1.3 µM vs. > 100 µM and 2.1 µM vs. > 200 µM for bromosulfophthalein and indomethacin, respectively) Immunohistochemistry analysis showed that OAT2 protein was localized to both basolateral and apical membranes of human and cynomolgus monkey renal proximal tubules, but appeared only on the apical membrane of rat proximal tubules. Collectively, the findings revealed the important role of OAT2 in renal secretion and possible reabsorption of creatinine and suggested a molecular basis for potential species difference in the transporter handling of creatinine. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  19. Critical study of high efficiency deep grinding

    OpenAIRE

    Johnstone, lain

    2002-01-01

    The recent years, the aerospace industry in particular has embraced and actively pursued the development of stronger high performance materials, namely nickel based superalloys and hardwearing steels. This has resulted in a need for a more efficient method of machining, and this need was answered with the advent of High Efficiency Deep Grinding (HEDG). This relatively new process using Cubic Boron Nitride (CBN) electroplated grinding wheels has been investigated through experim...

  20. Highly efficient and porous TiO{sub 2}-coated Ag@Fe{sub 3}O{sub 4}@C-Au microspheres for degradation of organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Mao, E-mail: shenmao19820808@163.com; Chen, Suqing, E-mail: 465060605@qq.com; Jia, Wenping, E-mail: tzcjwp@tzc.edu.cn [Taizhou University, College of Pharmaceutical and Chemical Engineering (China); Fan, Guodong, E-mail: fangd@sust.edu.cn [Shan xi University of Science and Technology, Key Laboratory of Auxiliary Chemistry and Technology for Chemical Industry, Ministry of Education (China); Jin, Yanxian, E-mail: shirleyj@tzc.edu.cn; Liang, Huading, E-mail: shanjian8208@163.com [Taizhou University, College of Pharmaceutical and Chemical Engineering (China)

    2016-12-15

    In this paper, we reported a novel hierarchical porous Ag@Fe{sub 3}O{sub 4}@C-Au@TiO{sub 2} core@shell microspheres with a highly photocatalytic activity and magnetically separable properties. The synthesis method is included of a Fe{sub 3}O{sub 4} magnetic embedded Ag core (Ag@Fe{sub 3}O{sub 4}), an interlayer of carbon modified by PEI to form sufficient amounts of amine functional groups (Ag@Fe{sub 3}O{sub 4}@C-PEI), the grafting of Au nanoparticles on the surface of Ag@Fe{sub 3}O{sub 4}@C-PEI (Ag@Fe{sub 3}O{sub 4}@C-Au), and an ordered porous TiO{sub 2} structured shell. As an example of the applications, the photocatalytic activities of the samples were investigated by the reduction of Rhodamine B (RhB) under visible-light irradiation. The results show that the porous Ag@Fe{sub 3}O{sub 4}@C-Au@TiO{sub 2} core@shell microspheres display higher adsorption and photocatalytic activities compared to the pure porous TiO{sub 2} and Ag@Fe{sub 3}O{sub 4}@C@TiO{sub 2} microspheres, which are attributed to the local surface plasmon resonance (LSPR) by the Ag and Au nanoparticles and the high specific surface area.

  1. High-Efficient Low-Cost Photovoltaics Recent Developments

    CERN Document Server

    Petrova-Koch, Vesselinka; Goetzberger, Adolf

    2009-01-01

    A bird's-eye view of the development and problems of recent photovoltaic cells and systems and prospects for Si feedstock is presented. High-efficient low-cost PV modules, making use of novel efficient solar cells (based on c-Si or III-V materials), and low cost solar concentrators are in the focus of this book. Recent developments of organic photovoltaics, which is expected to overcome its difficulties and to enter the market soon, are also included.

  2. High transconductance organic electrochemical transistors

    Science.gov (United States)

    Khodagholy, Dion; Rivnay, Jonathan; Sessolo, Michele; Gurfinkel, Moshe; Leleux, Pierre; Jimison, Leslie H.; Stavrinidou, Eleni; Herve, Thierry; Sanaur, Sébastien; Owens, Róisín M.; Malliaras, George G.

    2013-07-01

    The development of transistors with high gain is essential for applications ranging from switching elements and drivers to transducers for chemical and biological sensing. Organic transistors have become well-established based on their distinct advantages, including ease of fabrication, synthetic freedom for chemical functionalization, and the ability to take on unique form factors. These devices, however, are largely viewed as belonging to the low-end of the performance spectrum. Here we present organic electrochemical transistors with a transconductance in the mS range, outperforming transistors from both traditional and emerging semiconductors. The transconductance of these devices remains fairly constant from DC up to a frequency of the order of 1 kHz, a value determined by the process of ion transport between the electrolyte and the channel. These devices, which continue to work even after being crumpled, are predicted to be highly relevant as transducers in biosensing applications.

  3. High transconductance organic electrochemical transistors

    Science.gov (United States)

    Khodagholy, Dion; Rivnay, Jonathan; Sessolo, Michele; Gurfinkel, Moshe; Leleux, Pierre; Jimison, Leslie H.; Stavrinidou, Eleni; Herve, Thierry; Sanaur, Sébastien; Owens, Róisín M.; Malliaras, George G.

    2013-01-01

    The development of transistors with high gain is essential for applications ranging from switching elements and drivers to transducers for chemical and biological sensing. Organic transistors have become well-established based on their distinct advantages, including ease of fabrication, synthetic freedom for chemical functionalization, and the ability to take on unique form factors. These devices, however, are largely viewed as belonging to the low-end of the performance spectrum. Here we present organic electrochemical transistors with a transconductance in the mS range, outperforming transistors from both traditional and emerging semiconductors. The transconductance of these devices remains fairly constant from DC up to a frequency of the order of 1 kHz, a value determined by the process of ion transport between the electrolyte and the channel. These devices, which continue to work even after being crumpled, are predicted to be highly relevant as transducers in biosensing applications. PMID:23851620

  4. High-efficiency white OLEDs based on small molecules

    Science.gov (United States)

    Hatwar, Tukaram K.; Spindler, Jeffrey P.; Ricks, M. L.; Young, Ralph H.; Hamada, Yuuhiko; Saito, N.; Mameno, Kazunobu; Nishikawa, Ryuji; Takahashi, Hisakazu; Rajeswaran, G.

    2004-02-01

    Eastman Kodak Company and SANYO Electric Co., Ltd. recently demonstrated a 15" full-color, organic light-emitting diode display (OLED) using a high-efficiency white emitter combined with a color-filter array. Although useful for display applications, white emission from organic structures is also under consideration for other applications, such as solid-state lighting, where high efficiency and good color rendition are important. By incorporating adjacent blue and orange emitting layers in a multi-layer structure, highly efficient, stable white emission has been attained. With suitable host and dopant combinations, a luminance yield of 20 cd/A and efficiency of 8 lm/W have been achieved at a drive voltage of less than 8 volts and luminance level of 1000 cd/m2. The estimated external efficiency of this device is 6.3% and a high level of operational stability is observed. To our knowledge, this is the highest performance reported so far for white organic electroluminescent devices. We will review white OLED technology and discuss the fabrication and operating characteristics of these devices.

  5. Constructing organic D-A-π-A-featured sensitizers with a quinoxaline unit for high-efficiency solar cells: the effect of an auxiliary acceptor on the absorption and the energy level alignment.

    Science.gov (United States)

    Pei, Kai; Wu, Yongzhen; Wu, Wenjun; Zhang, Qiong; Chen, Baoqin; Tian, He; Zhu, Weihong

    2012-06-25

    Four organic D-A-π-A-featured sensitizers (TQ1, TQ2, IQ1, and IQ2) have been studied for high-efficiency dye-sensitized solar cells (DSSCs). We employed an indoline or a triphenylamine unit as the donor, cyanoacetic acid as the acceptor/anchor, and a thiophene moiety as the conjugation bridge. Additionally, an electron-withdrawing quinoxaline unit was incorporated between the donor and the π-conjugation unit. These sensitizers show an additional absorption band covering the broad visible range in solution. The contribution from the incorporated quinoxaline was investigated theoretically by using DFT and time-dependent DFT. The incorporated low-band-gap quinoxaline unit as an auxiliary acceptor has several merits, such as decreasing the band gap, optimizing the energy levels, and realizing a facile structural modification on several positions in the quinoxaline unit. As demonstrated, the observed additional absorption band is favorable to the photon-to-electron conversion because it corresponds to the efficient electron transitions to the LUMO orbital. Electrochemical impedance spectroscopy (EIS) Bode plots reveal that the replacement of a methoxy group with an octyloxy group can increase the injection electron lifetime by a factor of 2.4. IQ2 and TQ2 can perform well without any co-adsorbent, successfully suppress the charge recombination from TiO(2) conduction band to I(3)(-) in the electrolyte, and enhance the electron lifetime, resulting in a decreased dark current and enhanced open circuit voltage (V(oc)) values. By using a liquid electrolyte, DSSCs based on dye IQ2 exhibited a broad incident photon-to-current conversion efficiency (IPCE) action spectrum and high efficiency (η=8.50 %) with a short circuit current density (J(sc)) of 15.65 mA cm(-2), a V(oc) value of 776 mV, a fill factor (FF) of 0.70 under AM 1.5 illumination (100 mW cm(-2)). Moreover, the overall efficiency remained at 97% of the initial value after 1000 h of visible

  6. Measure Guideline. High Efficiency Natural Gas Furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Brand, L. [Partnership for Advanced Residential Retrofit (PARR), Des Plaines, IL (United States); Rose, W. [Partnership for Advanced Residential Retrofit (PARR), Des Plaines, IL (United States)

    2012-10-01

    This measure guideline covers installation of high-efficiency gas furnaces, including: when to install a high-efficiency gas furnace as a retrofit measure; how to identify and address risks; and the steps to be used in the selection and installation process. The guideline is written for Building America practitioners and HVAC contractors and installers. It includes a compilation of information provided by manufacturers, researchers, and the Department of Energy as well as recent research results from the Partnership for Advanced Residential Retrofit (PARR) Building America team.

  7. Measure Guideline: High Efficiency Natural Gas Furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Brand, L.; Rose, W.

    2012-10-01

    This Measure Guideline covers installation of high-efficiency gas furnaces. Topics covered include when to install a high-efficiency gas furnace as a retrofit measure, how to identify and address risks, and the steps to be used in the selection and installation process. The guideline is written for Building America practitioners and HVAC contractors and installers. It includes a compilation of information provided by manufacturers, researchers, and the Department of Energy as well as recent research results from the Partnership for Advanced Residential Retrofit (PARR) Building America team.

  8. High efficiency, variable geometry, centrifugal cryogenic pump

    International Nuclear Information System (INIS)

    Forsha, M.D.; Nichols, K.E.; Beale, C.A.

    1994-01-01

    A centrifugal cryogenic pump has been developed which has a basic design that is rugged and reliable with variable speed and variable geometry features that achieve high pump efficiency over a wide range of head-flow conditions. The pump uses a sealless design and rolling element bearings to achieve high reliability and the ruggedness to withstand liquid-vapor slugging. The pump can meet a wide range of variable head, off-design flow requirements and maintain design point efficiency by adjusting the pump speed. The pump also has features that allow the impeller and diffuser blade heights to be adjusted. The adjustable height blades were intended to enhance the pump efficiency when it is operating at constant head, off-design flow rates. For small pumps, the adjustable height blades are not recommended. For larger pumps, they could provide off-design efficiency improvements. This pump was developed for supercritical helium service, but the design is well suited to any cryogenic application where high efficiency is required over a wide range of head-flow conditions

  9. Saving energy via high-efficiency fans.

    Science.gov (United States)

    Heine, Thomas

    2016-08-01

    Thomas Heine, sales and market manager for EC Upgrades, the retrofit arm of global provider of air movement solutions, ebm-papst A&NZ, discusses the retrofitting of high-efficiency fans to existing HVAC equipment to 'drastically reduce energy consumption'.

  10. 2.5% efficient organic plastic solar cells

    NARCIS (Netherlands)

    Shaheen, Sean E.; Brabec, Christoph J.; Sariciftci, N. Serdar; Padinger, Franz; Fromherz, Thomas; Hummelen, Jan C.

    2001-01-01

    We show that the power conversion efficiency of organic photovoltaic devices based on a conjugated polymer/methanofullerene blend is dramatically affected by molecular morphology. By structuring the blend to be a more intimate mixture that contains less phase segregation of methanofullerenes, and

  11. Origin of size effect on efficiency of organic photovoltaics

    DEFF Research Database (Denmark)

    Manor, Assaf; Katz, Eugene A.; Tromholt, Thomas

    2011-01-01

    It is widely accepted that efficiency of organic solar cells could be limited by their size. However, the published data on this effect are very limited and none of them includes analysis of light intensity dependence of the key cell parameters. We report such analysis for bulk heterojunction sol...

  12. High Efficiency Reversible Fuel Cell Power Converter

    DEFF Research Database (Denmark)

    Pittini, Riccardo

    as well as different dc-ac and dc-dc converter topologies are presented and analyzed. A new ac-dc topology for high efficiency data center applications is proposed and an efficiency characterization based on the fuel cell stack I-V characteristic curve is presented. The second part discusses the main...... converter components. Wide bandgap power semiconductors are introduced due to their superior performance in comparison to traditional silicon power devices. The analysis presents a study based on switching loss measurements performed on Si IGBTs, SiC JFETs, SiC MOSFETs and their respective gate drivers...

  13. High Efficiency Power Converter for Low Voltage High Power Applications

    DEFF Research Database (Denmark)

    Nymand, Morten

    The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based......, and remote power generation for light towers, camper vans, boats, beacons, and buoys etc. A review of current state-of-the-art is presented. The best performing converters achieve moderately high peak efficiencies at high input voltage and medium power level. However, system dimensioning and cost are often...

  14. High Efficiency Centrifugal Compressor for Rotorcraft Applications

    Science.gov (United States)

    Medic, Gorazd; Sharma, Om P.; Jongwook, Joo; Hardin, Larry W.; McCormick, Duane C.; Cousins, William T.; Lurie, Elizabeth A.; Shabbir, Aamir; Holley, Brian M.; Van Slooten, Paul R.

    2017-01-01

    A centrifugal compressor research effort conducted by United Technologies Research Center under NASA Research Announcement NNC08CB03C is documented. The objectives were to identify key technical barriers to advancing the aerodynamic performance of high-efficiency, high work factor, compact centrifugal compressor aft-stages for turboshaft engines; to acquire measurements needed to overcome the technical barriers and inform future designs; to design, fabricate, and test a new research compressor in which to acquire the requisite flow field data. A new High-Efficiency Centrifugal Compressor stage -- splittered impeller, splittered diffuser, 90 degree bend, and exit guide vanes -- with aerodynamically aggressive performance and configuration (compactness) goals were designed, fabricated, and subquently tested at the NASA Glenn Research Center.

  15. High-Temperature High-Efficiency Solar Thermoelectric Generators

    Energy Technology Data Exchange (ETDEWEB)

    Baranowski, LL; Warren, EL; Toberer, ES

    2014-03-01

    Inspired by recent high-efficiency thermoelectric modules, we consider thermoelectrics for terrestrial applications in concentrated solar thermoelectric generators (STEGs). The STEG is modeled as two subsystems: a TEG, and a solar absorber that efficiently captures the concentrated sunlight and limits radiative losses from the system. The TEG subsystem is modeled using thermoelectric compatibility theory; this model does not constrain the material properties to be constant with temperature. Considering a three-stage TEG based on current record modules, this model suggests that 18% efficiency could be experimentally expected with a temperature gradient of 1000A degrees C to 100A degrees C. Achieving 15% overall STEG efficiency thus requires an absorber efficiency above 85%, and we consider two methods to achieve this: solar-selective absorbers and thermally insulating cavities. When the TEG and absorber subsystem models are combined, we expect that the STEG modeled here could achieve 15% efficiency with optical concentration between 250 and 300 suns.

  16. High efficiency and broadband acoustic diodes

    Science.gov (United States)

    Fu, Congyi; Wang, Bohan; Zhao, Tianfei; Chen, C. Q.

    2018-01-01

    Energy transmission efficiency and working bandwidth are the two major factors limiting the application of current acoustic diodes (ADs). This letter presents a design of high efficiency and broadband acoustic diodes composed of a nonlinear frequency converter and a linear wave filter. The converter consists of two masses connected by a bilinear spring with asymmetric tension and compression stiffness. The wave filter is a linear mass-spring lattice (sonic crystal). Both numerical simulation and experiment show that the energy transmission efficiency of the acoustic diode can be improved by as much as two orders of magnitude, reaching about 61%. Moreover, the primary working band width of the AD is about two times of the cut-off frequency of the sonic crystal filter. The cut-off frequency dependent working band of the AD implies that the developed AD can be scaled up or down from macro-scale to micro- and nano-scale.

  17. Complexity-aware high efficiency video coding

    CERN Document Server

    Correa, Guilherme; Agostini, Luciano; Cruz, Luis A da Silva

    2016-01-01

    This book discusses computational complexity of High Efficiency Video Coding (HEVC) encoders with coverage extending from the analysis of HEVC compression efficiency and computational complexity to the reduction and scaling of its encoding complexity. After an introduction to the topic and a review of the state-of-the-art research in the field, the authors provide a detailed analysis of the HEVC encoding tools compression efficiency and computational complexity.  Readers will benefit from a set of algorithms for scaling the computational complexity of HEVC encoders, all of which take advantage from the flexibility of the frame partitioning structures allowed by the standard.  The authors also provide a set of early termination methods based on data mining and machine learning techniques, which are able to reduce the computational complexity required to find the best frame partitioning structures. The applicability of the proposed methods is finally exemplified with an encoding time control system that emplo...

  18. High Efficiency, Low Emission Refrigeration System

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Brian A [ORNL; Sharma, Vishaldeep [ORNL

    2016-08-01

    Supermarket refrigeration systems account for approximately 50% of supermarket energy use, placing this class of equipment among the highest energy consumers in the commercial building domain. In addition, the commonly used refrigeration system in supermarket applications is the multiplex direct expansion (DX) system, which is prone to refrigerant leaks due to its long lengths of refrigerant piping. This leakage reduces the efficiency of the system and increases the impact of the system on the environment. The high Global Warming Potential (GWP) of the hydrofluorocarbon (HFC) refrigerants commonly used in these systems, coupled with the large refrigerant charge and the high refrigerant leakage rates leads to significant direct emissions of greenhouse gases into the atmosphere. Methods for reducing refrigerant leakage and energy consumption are available, but underutilized. Further work needs to be done to reduce costs of advanced system designs to improve market utilization. In addition, refrigeration system retrofits that result in reduced energy consumption are needed since the majority of applications address retrofits rather than new stores. The retrofit market is also of most concern since it involves large-volume refrigerant systems with high leak rates. Finally, alternative refrigerants for new and retrofit applications are needed to reduce emissions and reduce the impact on the environment. The objective of this Collaborative Research and Development Agreement (CRADA) between the Oak Ridge National Laboratory and Hill Phoenix is to develop a supermarket refrigeration system that reduces greenhouse gas emissions and has 25 to 30 percent lower energy consumption than existing systems. The outcomes of this project will include the design of a low emission, high efficiency commercial refrigeration system suitable for use in current U.S. supermarkets. In addition, a prototype low emission, high efficiency supermarket refrigeration system will be produced for

  19. High efficiency novel window air conditioner

    International Nuclear Information System (INIS)

    Bansal, Pradeep

    2015-01-01

    Highlights: • Use of novel refrigerant mixture of R32/R125 (85/15% molar conc.) to reduce global warming and improve energy efficiency. • Use of novel features such as electronically commuted motor (ECM) fan motor, slinger and sub-merged sub-cooler. • Energy savings of up to 0.1 Quads per year in USA and much more in Asia/Middle East where WACs are used in large numbers. • Payback period of only 1.4 years of the novel efficient WAC. - Abstract: This paper presents the results of an experimental and analytical evaluation of measures to raise the efficiency of window air conditioners (WAC). In order to achieve a higher energy efficiency ratio (EER), the original capacity of a baseline R410A unit was reduced by replacing the original compressor with a lower capacity but higher EER compressor, while all heat exchangers and the chassis from the original unit were retained. Subsequent major modifications included – replacing the alternating current fan motor with a brushless high efficiency electronically commutated motor (ECM) motor, replacing the capillary tube with a needle valve to better control the refrigerant flow and refrigerant set points, and replacing R410A with a ‘drop-in’ lower global warming potential (GWP) binary mixture of R32/R125 (85/15% molar concentration). All these modifications resulted in significant enhancement in the EER of the baseline WAC. Further, an economic analysis of the new WAC revealed an encouraging payback period

  20. High efficiency carbon nanotube thread antennas

    Science.gov (United States)

    Amram Bengio, E.; Senic, Damir; Taylor, Lauren W.; Tsentalovich, Dmitri E.; Chen, Peiyu; Holloway, Christopher L.; Babakhani, Aydin; Long, Christian J.; Novotny, David R.; Booth, James C.; Orloff, Nathan D.; Pasquali, Matteo

    2017-10-01

    Although previous research has explored the underlying theory of high-frequency behavior of carbon nanotubes (CNTs) and CNT bundles for antennas, there is a gap in the literature for direct experimental measurements of radiation efficiency. These measurements are crucial for any practical application of CNT materials in wireless communication. In this letter, we report a measurement technique to accurately characterize the radiation efficiency of λ/4 monopole antennas made from the CNT thread. We measure the highest absolute values of radiation efficiency for CNT antennas of any type, matching that of copper wire. To capture the weight savings, we propose a specific radiation efficiency metric and show that these CNT antennas exceed copper's performance by over an order of magnitude at 1 GHz and 2.4 GHz. We also report direct experimental observation that, contrary to metals, the radiation efficiency of the CNT thread improves significantly at higher frequencies. These results pave the way for practical applications of CNT thread antennas, particularly in the aerospace and wearable electronics industries where weight saving is a priority.

  1. High Efficiency Power Converter for Low Voltage High Power Applications

    DEFF Research Database (Denmark)

    Nymand, Morten

    The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based...

  2. High efficiency lithium-thionyl chloride cell

    Science.gov (United States)

    Doddapaneni, N.

    1982-08-01

    The polarization characteristics and the specific cathode capacity of Teflon bonded carbon electrodes in the Li/SOCl2 system have been evaluated. Doping of electrocatalysts such as cobalt and iron phthalocyanine complexes improved both cell voltage and cell rate capability. High efficiency Li/SOCl2 cells were thus achieved with catalyzed cathodes. The electrochemical reduction of SOCl2 seems to undergo modification at catalyzed cathode. For example, the reduction of SOCl2 at FePc catalyzed cathode involves 2-1/2 e-/mole of SOCl2. Furthermore, the reduction mechanism is simplified and unwanted chemical species are eliminated by the catalyst. Thus a potentially safer high efficiency Li/SOCl2 can be anticipated.

  3. IMPACT OF ENVIRONMENTAL FACTORS ON THE EFFICIENCY OF TAX ORGANIZATIONS

    Directory of Open Access Journals (Sweden)

    Marios Tsakas

    2014-05-01

    Full Text Available The study examines the performance of tax organizations in Greece, based on data obtained from a sample of 35 tax offices. Performance evaluation was conducted using DEA with bootstrap methods. In addition, Tobit regression analysis was employed to examine the environmental variables that impact on the efficiency performance of these tax offices. From the analysis, weaknesses, and management issues are derived from the tax offices inefficiency. The general conclusion is that a robust governance structure within the tax office operational framework is needed in order to improve organisational efficiency.

  4. Bioblendstocks that Enable High Efficiency Engine Designs

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, Robert L.; Fioroni, Gina M.; Ratcliff, Matthew A.; Zigler, Bradley T.; Farrell, John

    2016-11-03

    The past decade has seen a high level of innovation in production of biofuels from sugar, lipid, and lignocellulose feedstocks. As discussed in several talks at this workshop, ethanol blends in the E25 to E50 range could enable more highly efficient spark-ignited (SI) engines. This is because of their knock resistance properties that include not only high research octane number (RON), but also charge cooling from high heat of vaporization, and high flame speed. Emerging alcohol fuels such as isobutanol or mixed alcohols have desirable properties such as reduced gasoline blend vapor pressure, but also have lower RON than ethanol. These fuels may be able to achieve the same knock resistance benefits, but likely will require higher blend levels or higher RON hydrocarbon blendstocks. A group of very high RON (>150) oxygenates such as dimethyl furan, methyl anisole, and related compounds are also produced from biomass. While providing no increase in charge cooling, their very high octane numbers may provide adequate knock resistance for future highly efficient SI engines. Given this range of options for highly knock resistant fuels there appears to be a critical need for a fuel knock resistance metric that includes effects of octane number, heat of vaporization, and potentially flame speed. Emerging diesel fuels include highly branched long-chain alkanes from hydroprocessing of fats and oils, as well as sugar-derived terpenoids. These have relatively high cetane number (CN), which may have some benefits in designing more efficient CI engines. Fast pyrolysis of biomass can produce diesel boiling range streams that are high in aromatic, oxygen and acid contents. Hydroprocessing can be applied to remove oxygen and consequently reduce acidity, however there are strong economic incentives to leave up to 2 wt% oxygen in the product. This oxygen will primarily be present as low CN alkyl phenols and aryl ethers. While these have high heating value, their presence in diesel fuel

  5. Evaluating performance of high efficiency mist eliminators

    Energy Technology Data Exchange (ETDEWEB)

    Waggoner, Charles A.; Parsons, Michael S.; Giffin, Paxton K. [Mississippi State University, Institute for Clean Energy Technology, 205 Research Blvd, Starkville, MS (United States)

    2013-07-01

    Processing liquid wastes frequently generates off gas streams with high humidity and liquid aerosols. Droplet laden air streams can be produced from tank mixing or sparging and processes such as reforming or evaporative volume reduction. Unfortunately these wet air streams represent a genuine threat to HEPA filters. High efficiency mist eliminators (HEME) are one option for removal of liquid aerosols with high dissolved or suspended solids content. HEMEs have been used extensively in industrial applications, however they have not seen widespread use in the nuclear industry. Filtering efficiency data along with loading curves are not readily available for these units and data that exist are not easily translated to operational parameters in liquid waste treatment plants. A specialized test stand has been developed to evaluate the performance of HEME elements under use conditions of a US DOE facility. HEME elements were tested at three volumetric flow rates using aerosols produced from an iron-rich waste surrogate. The challenge aerosol included submicron particles produced from Laskin nozzles and super micron particles produced from a hollow cone spray nozzle. Test conditions included ambient temperature and relative humidities greater than 95%. Data collected during testing HEME elements from three different manufacturers included volumetric flow rate, differential temperature across the filter housing, downstream relative humidity, and differential pressure (dP) across the filter element. Filter challenge was discontinued at three intermediate dPs and the filter to allow determining filter efficiency using dioctyl phthalate and then with dry surrogate aerosols. Filtering efficiencies of the clean HEME, the clean HEME loaded with water, and the HEME at maximum dP were also collected using the two test aerosols. Results of the testing included differential pressure vs. time loading curves for the nine elements tested along with the mass of moisture and solid

  6. High efficiency inverter and ballast circuits

    International Nuclear Information System (INIS)

    Nilssen, O.K.

    1984-01-01

    A high efficiency push-pull inverter circuit employing a pair of relatively high power switching transistors is described. The switching on and off of the transistors is precisely controlled to minimize power losses due to common-mode conduction or due to transient conditions that occur in the process of turning a transistor on or off. Two current feed-back transformers are employed in the transistor base drives; one being saturable for providing a positive feedback, and the other being non-saturable for providing a subtractive feedback

  7. Optimization of a high efficiency FEL amplifier

    International Nuclear Information System (INIS)

    Schneidmiller, E.A.; Yurkov, M.V.

    2014-10-01

    The problem of an efficiency increase of an FEL amplifier is now of great practical importance. Technique of undulator tapering in the post-saturation regime is used at the existing X-ray FELs LCLS and SACLA, and is planned for use at the European XFEL, Swiss FEL, and PAL XFEL. There are also discussions on the future of high peak and average power FELs for scientific and industrial applications. In this paper we perform detailed analysis of the tapering strategies for high power seeded FEL amplifiers. Application of similarity techniques allows us to derive universal law of the undulator tapering.

  8. Green synthesis of the reduced graphene oxide–CuI quasi-shell–core nanocomposite: A highly efficient and stable solar-light-induced catalyst for organic dye degradation in water

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jiha; Reddy, D. Amaranatha; Islam, M. Jahurul [Department of Chemistry and Chemical Institute for Functional Materials, Pusan National University, Busan 609-735 (Korea, Republic of); Seo, Bora [Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of); Joo, Sang Hoon [Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of); School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of); Kim, Tae Kyu, E-mail: tkkim@pusan.ac.kr [Department of Chemistry and Chemical Institute for Functional Materials, Pusan National University, Busan 609-735 (Korea, Republic of)

    2015-12-15

    Graphical abstract: - Highlights: • Green synthesis of RGO–CuI quasi-shell–core nanocomposites without any surfactant. • Promising candidates as solar light active photocatalyst for dye degradation. • Significant improvement of the photocatalytic activity in RGO wrapped composites. • The best photocatalytic activity to RhB has been attained for CuI–RGO (2 mg mL{sup −1}). - Abstract: Surfactant-free, reduced graphene oxide (RGO)–CuI quasi-shell−core nanocomposites were successfully synthesized using ultra-sonication assisted chemical method at room temperature. The morphologies, structures and optical properties of the CuI and CuI–RGO nanocomposites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transformed infrared spectroscopy (FTIR), UV–visible absorption spectroscopy, and photoluminescence (PL) spectroscopy. Morphological and structural analyses indicated that the CuI–RGO core–shell nanocomposites comprise single-crystalline face-centered cubic phase CuI nanostructures, coated with a thin RGO quasi-shell. Photocatalysis experiments revealed that the as-synthesized CuI–RGO nanocomposites exhibit remarkably enhanced photocatalytic activities and stabilities for photo degradation of Rhodamine-B (RhB) organic dye under simulated solar light irradiation. The photo degradation ability is strongly affected by the concentration of RGO in the nanocomposites; the highest photodegradation rate was obtained at a graphene loading content of 2 mg mL{sup −1} nanocomposite. The remarkable photocatalytic performance of the CuI–RGO nanocomposites mainly originates from their unique adsorption and electron-accepting and electron-transporting properties of RGO. The present work provides a novel green synthetic route to producing CuI–RGO nanocomposites without toxic solvents or reducing agents, thereby providing highly efficient and stable solar light

  9. Green synthesis of the reduced graphene oxide–CuI quasi-shell–core nanocomposite: A highly efficient and stable solar-light-induced catalyst for organic dye degradation in water

    International Nuclear Information System (INIS)

    Choi, Jiha; Reddy, D. Amaranatha; Islam, M. Jahurul; Seo, Bora; Joo, Sang Hoon; Kim, Tae Kyu

    2015-01-01

    Graphical abstract: - Highlights: • Green synthesis of RGO–CuI quasi-shell–core nanocomposites without any surfactant. • Promising candidates as solar light active photocatalyst for dye degradation. • Significant improvement of the photocatalytic activity in RGO wrapped composites. • The best photocatalytic activity to RhB has been attained for CuI–RGO (2 mg mL −1 ). - Abstract: Surfactant-free, reduced graphene oxide (RGO)–CuI quasi-shell−core nanocomposites were successfully synthesized using ultra-sonication assisted chemical method at room temperature. The morphologies, structures and optical properties of the CuI and CuI–RGO nanocomposites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transformed infrared spectroscopy (FTIR), UV–visible absorption spectroscopy, and photoluminescence (PL) spectroscopy. Morphological and structural analyses indicated that the CuI–RGO core–shell nanocomposites comprise single-crystalline face-centered cubic phase CuI nanostructures, coated with a thin RGO quasi-shell. Photocatalysis experiments revealed that the as-synthesized CuI–RGO nanocomposites exhibit remarkably enhanced photocatalytic activities and stabilities for photo degradation of Rhodamine-B (RhB) organic dye under simulated solar light irradiation. The photo degradation ability is strongly affected by the concentration of RGO in the nanocomposites; the highest photodegradation rate was obtained at a graphene loading content of 2 mg mL −1 nanocomposite. The remarkable photocatalytic performance of the CuI–RGO nanocomposites mainly originates from their unique adsorption and electron-accepting and electron-transporting properties of RGO. The present work provides a novel green synthetic route to producing CuI–RGO nanocomposites without toxic solvents or reducing agents, thereby providing highly efficient and stable solar light-induced RGO

  10. Copper(I) Thiocyanate (CuSCN) Hole-Transport Layers Processed from Aqueous Precursor Solutions and Their Application in Thin-Film Transistors and Highly Efficient Organic and Organometal Halide Perovskite Solar Cells

    KAUST Repository

    Wijeyasinghe, Nilushi

    2017-07-28

    This study reports the development of copper(I) thiocyanate (CuSCN) hole-transport layers (HTLs) processed from aqueous ammonia as a novel alternative to conventional n-alkyl sulfide solvents. Wide bandgap (3.4–3.9 eV) and ultrathin (3–5 nm) layers of CuSCN are formed when the aqueous CuSCN–ammine complex solution is spin-cast in air and annealed at 100 °C. X-ray photoelectron spectroscopy confirms the high compositional purity of the formed CuSCN layers, while the high-resolution valence band spectra agree with first-principles calculations. Study of the hole-transport properties using field-effect transistor measurements reveals that the aqueous-processed CuSCN layers exhibit a fivefold higher hole mobility than films processed from diethyl sulfide solutions with the maximum values approaching 0.1 cm2 V−1 s−1. A further interesting characteristic is the low surface roughness of the resulting CuSCN layers, which in the case of solar cells helps to planarize the indium tin oxide anode. Organic bulk heterojunction and planar organometal halide perovskite solar cells based on aqueous-processed CuSCN HTLs yield power conversion efficiency of 10.7% and 17.5%, respectively. Importantly, aqueous-processed CuSCN-based cells consistently outperform devices based on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate HTLs. This is the first report on CuSCN films and devices processed via an aqueous-based synthetic route that is compatible with high-throughput manufacturing and paves the way for further developments.

  11. High Efficiency Colloidal Quantum Dot Phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Kahen, Keith

    2013-12-31

    The project showed that non-Cd containing, InP-based nanocrystals (semiconductor materials with dimensions of ~6 nm) have high potential for enabling next-generation, nanocrystal-based, on chip phosphors for solid state lighting. Typical nanocrystals fall short of the requirements for on chip phosphors due to their loss of quantum efficiency under the operating conditions of LEDs, such as, high temperature (up to 150 °C) and high optical flux (up to 200 W/cm2). The InP-based nanocrystals invented during this project maintain high quantum efficiency (>80%) in polymer-based films under these operating conditions for emission wavelengths ranging from ~530 to 620 nm. These nanocrystals also show other desirable attributes, such as, lack of blinking (a common problem with nanocrystals which limits their performance) and no increase in the emission spectral width from room to 150 °C (emitters with narrower spectral widths enable higher efficiency LEDs). Prior to these nanocrystals, no nanocrystal system (regardless of nanocrystal type) showed this collection of properties; in fact, other nanocrystal systems are typically limited to showing only one desirable trait (such as high temperature stability) but being deficient in other properties (such as high flux stability). The project showed that one can reproducibly obtain these properties by generating a novel compositional structure inside of the nanomaterials; in addition, the project formulated an initial theoretical framework linking the compositional structure to the list of high performance optical properties. Over the course of the project, the synthetic methodology for producing the novel composition was evolved to enable the synthesis of these nanomaterials at a cost approximately equal to that required for forming typical conventional nanocrystals. Given the above results, the last major remaining step prior to scale up of the nanomaterials is to limit the oxidation of these materials during the tens of

  12. Highly Efficient Estimators of Multivariate Location with High Breakdown Point

    NARCIS (Netherlands)

    Lopuhaa, H.P.

    1991-01-01

    We propose an affine equivariant estimator of multivariate location that combines a high breakdown point and a bounded influence function with high asymptotic efficiency. This proposal is basically a location $M$-estimator based on the observations obtained after scaling with an affine equivariant

  13. Efficient and bright organic light-emitting diodes on single-layer graphene electrodes

    Science.gov (United States)

    Li, Ning; Oida, Satoshi; Tulevski, George S.; Han, Shu-Jen; Hannon, James B.; Sadana, Devendra K.; Chen, Tze-Chiang

    2013-08-01

    Organic light-emitting diodes are emerging as leading technologies for both high quality display and lighting. However, the transparent conductive electrode used in the current organic light-emitting diode technologies increases the overall cost and has limited bendability for future flexible applications. Here we use single-layer graphene as an alternative flexible transparent conductor, yielding white organic light-emitting diodes with brightness and efficiency sufficient for general lighting. The performance improvement is attributed to the device structure, which allows direct hole injection from the single-layer graphene anode into the light-emitting layers, reducing carrier trapping induced efficiency roll-off. By employing a light out-coupling structure, phosphorescent green organic light-emitting diodes exhibit external quantum efficiency >60%, while phosphorescent white organic light-emitting diodes exhibit external quantum efficiency >45% at 10,000 cd m-2 with colour rendering index of 85. The power efficiency of white organic light-emitting diodes reaches 80 lm W-1 at 3,000 cd m-2, comparable to the most efficient lighting technologies.

  14. Highly efficient light management for perovskite solar cells.

    Science.gov (United States)

    Wang, Dong-Lin; Cui, Hui-Juan; Hou, Guo-Jiao; Zhu, Zhen-Gang; Yan, Qing-Bo; Su, Gang

    2016-01-06

    Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing a higher conversion efficiency of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells. Here, we focus on another significant aspect that is to minimize the light loss by optimizing the light management to gain a high efficiency for perovskite solar cells. In our scheme, the slotted and inverted prism structured SiO2 layers are adopted to trap more light into the solar cells, and a better transparent conducting oxide layer is employed to reduce the parasitic absorption. For such an implementation, the efficiency and the serviceable angle of the perovskite solar cell can be promoted impressively. This proposal would shed new light on developing the high-performance perovskite solar cells.

  15. High efficiency motors; Motores de alta eficiencia

    Energy Technology Data Exchange (ETDEWEB)

    Uranga Favela, Ivan Jaime [Energia Controlada de Mexico, S. A. de C. V., Mexico, D. F. (Mexico)

    1993-12-31

    This paper is a technical-financial study of the high efficiency and super-premium motors. As it is widely known, more than 60% of the electrical energy generated in the country is used for the operation of motors, in industry as well as in commerce. Therefore the importance that the motors have in the efficient energy use. [Espanol] El presente trabajo es un estudio tecnico-financiero de los motores de alta eficiencia y los motores super premium. Como es ampliamente conocido, mas del 60% de la energia electrica generada en el pais, es utilizada para accionar motores, dentro de la industria y el comercio. De alli la importancia que los motores tienen en el uso eficiente de la energia.

  16. High efficiency motors; Motores de alta eficiencia

    Energy Technology Data Exchange (ETDEWEB)

    Uranga Favela, Ivan Jaime [Energia Controlada de Mexico, S. A. de C. V., Mexico, D. F. (Mexico)

    1992-12-31

    This paper is a technical-financial study of the high efficiency and super-premium motors. As it is widely known, more than 60% of the electrical energy generated in the country is used for the operation of motors, in industry as well as in commerce. Therefore the importance that the motors have in the efficient energy use. [Espanol] El presente trabajo es un estudio tecnico-financiero de los motores de alta eficiencia y los motores super premium. Como es ampliamente conocido, mas del 60% de la energia electrica generada en el pais, es utilizada para accionar motores, dentro de la industria y el comercio. De alli la importancia que los motores tienen en el uso eficiente de la energia.

  17. High efficiency beam splitting for H- accelerators

    International Nuclear Information System (INIS)

    Kramer, S.L.; Stipp, V.; Krieger, C.; Madsen, J.

    1985-01-01

    Beam splitting for high energy accelerators has typically involved a significant loss of beam and radiation. This paper reports on a new method of splitting beams for H - accelerators. This technique uses a high intensity flash of light to strip a fraction of the H - beam to H 0 which are then easily separated by a small bending magnet. A system using a 900-watt (average electrical power) flashlamp and a highly efficient collector will provide 10 -3 to 10 -2 splitting of a 50 MeV H - beam. Results on the operation and comparisons with stripping cross sections are presented. Also discussed is the possibility for developing this system to yield a higher stripping fraction

  18. High Quantum Efficiency OLED Lighting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Shiang, Joseph [General Electric (GE) Global Research, Fairfield, CT (United States)

    2011-09-30

    The overall goal of the program was to apply improvements in light outcoupling technology to a practical large area plastic luminaire, and thus enable the product vision of an extremely thin form factor high efficiency large area light source. The target substrate was plastic and the baseline device was operating at 35 LPW at the start of the program. The target LPW of the program was a >2x improvement in the LPW efficacy and the overall amount of light to be delivered was relatively high 900 lumens. Despite the extremely difficult challenges associated with scaling up a wet solution process on plastic substrates, the program was able to make substantial progress. A small molecule wet solution process was successfully implemented on plastic substrates with almost no loss in efficiency in transitioning from the laboratory scale glass to large area plastic substrates. By transitioning to a small molecule based process, the LPW entitlement increased from 35 LPW to 60 LPW. A further 10% improvement in outcoupling efficiency was demonstrated via the use of a highly reflecting cathode, which reduced absorptive loss in the OLED device. The calculated potential improvement in some cases is even larger, ~30%, and thus there is considerable room for optimism in improving the net light coupling efficacy, provided absorptive loss mechanisms are eliminated. Further improvements are possible if scattering schemes such as the silver nanowire based hard coat structure are fully developed. The wet coating processes were successfully scaled to large area plastic substrate and resulted in the construction of a 900 lumens luminaire device.

  19. High-efficiency concentrator silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sinton, R.A.; Cuevas, A.; King, R.R.; Swanson, R.M. (Stanford Univ., CA (USA). Solid-State Electronics Lab.)

    1990-11-01

    This report presents results from extensive process development in high-efficiency Si solar cells. An advanced design for a 1.56-cm{sup 2} cell with front grids achieved 26% efficiency at 90 suns. This is especially significant since this cell does not require a prismatic cover glass. New designs for simplified backside-contact solar cells were advanced from a status of near-nonfunctionality to demonstrated 21--22% for one-sun cells in sizes up to 37.5 cm{sup 2}. An efficiency of 26% was achieved for similar 0.64-cm{sup 2} concentrator cells at 150 suns. More fundamental work on dopant-diffused regions is also presented here. The recombination vs. various process and physical parameters was studied in detail for boron and phosphorous diffusions. Emitter-design studies based solidly upon these new data indicate the performance vs design parameters for a variety of the cases of most interest to solar cell designers. Extractions of p-type bandgap narrowing and the surface recombination for p- and n-type regions from these studies have a generality that extends beyond solar cells into basic device modeling. 68 refs., 50 figs.

  20. Nanooptics for high efficient photon managment

    Science.gov (United States)

    Wyrowski, Frank; Schimmel, Hagen

    2005-09-01

    Optical systems for photon management, that is the generation of tailored electromagnetic fields, constitute one of the keys for innovation through photonics. An important subfield of photon management deals with the transformation of an incident light field into a field of specified intensity distribution. In this paper we consider some basic aspects of the nature of systems for those light transformations. It turns out, that the transversal redistribution of energy (TRE) is of central concern to achieve systems with high transformation efficiency. Besides established techniques nanostructured optical elements (NOE) are demanded to implement transversal energy redistribution. That builds a bridge between the needs of photon management, optical engineering, and nanooptics.

  1. Origin of poor doping efficiency in solution processed organic semiconductors.

    Science.gov (United States)

    Jha, Ajay; Duan, Hong-Guang; Tiwari, Vandana; Thorwart, Michael; Miller, R J Dwayne

    2018-05-21

    Doping is an extremely important process where intentional insertion of impurities in semiconductors controls their electronic properties. In organic semiconductors, one of the convenient, but inefficient, ways of doping is the spin casting of a precursor mixture of components in solution, followed by solvent evaporation. Active control over this process holds the key to significant improvements over current poor doping efficiencies. Yet, an optimized control can only come from a detailed understanding of electronic interactions responsible for the low doping efficiencies. Here, we use two-dimensional nonlinear optical spectroscopy to examine these interactions in the course of the doping process by probing the solution mixture of doped organic semiconductors. A dopant accepts an electron from the semiconductor and the two ions form a duplex of interacting charges known as ion-pair complexes. Well-resolved off-diagonal peaks in the two-dimensional spectra clearly demonstrate the electronic connectivity among the ions in solution. This electronic interaction represents a well resolved electrostatically bound state, as opposed to a random distribution of ions. We developed a theoretical model to recover the experimental data, which reveals an unexpectedly strong electronic coupling of ∼250 cm -1 with an intermolecular distance of ∼4.5 Å between ions in solution, which is approximately the expected distance in processed films. The fact that this relationship persists from solution to the processed film gives direct evidence that Coulomb interactions are retained from the precursor solution to the processed films. This memory effect renders the charge carriers equally bound also in the film and, hence, results in poor doping efficiencies. This new insight will help pave the way towards rational tailoring of the electronic interactions to improve doping efficiencies in processed organic semiconductor thin films.

  2. [Efficiency indicators to assess the organ donation and transplantation process: systematic review of the literature].

    Science.gov (United States)

    Siqueira, Marina Martins; Araujo, Claudia Affonso; de Aguiar Roza, Bartira; Schirmer, Janine

    2016-08-01

    To search the literature and identify indicators used to monitor and control the organ donation and transplantation process and to group these indicators into categories. In November 2014, a systematic review of the literature was carried out in the following databases: Biblioteca Virtual em Saúde (BVS), EBSCO, Emerald, Proquest, Science Direct, and Web of Science. The following search terms (and the corresponding terms in Brazilian Portuguese) were employed: "efficiency," "indicators," "organ donation," "tissue and organ procurement," and "organ transplantation." Of the 344 articles retrieved, 23 original articles published between 1992 and 2013 were selected and reviewed for analysis of efficiency indicators. The review revealed 117 efficiency indicators, which were grouped according to similarity of content and divided into three categories: 1) 71 indicators related to organ donation, covering mortality statistics, communication of brain death, clinical status of donors and exclusion of donors for medical reasons, attitude of families, confirmation of donations, and extraction of organs and tissues; 2) 22 indicators related to organ transplantation, covering the surgical procedure per se and post-transplantation follow-up; and 3) 24 indicators related to the demand for organs and the resources of hospitals involved in the process. Even if organ transplantation is a recent phenomenon, the high number of efficiency indicators described in the literature suggests that scholars interested in this field have been searching for ways to measure performance. However, there is little standardization of the indicators used. Also, most indicators focus on the donation step, suggesting gaps in the measurement of efficiency at others points in the process. Additional indicators are needed to monitor important stages, such as organ distribution (for example, organ loss indicators) and post-transplantation aspects (for example, survival and quality of life).

  3. Performance and energy efficiency in wireless self-organized networks

    Energy Technology Data Exchange (ETDEWEB)

    Gao, C.

    2009-07-01

    Self-organized packet radio networks (ad-hoc networks) and wireless sensor networks have got massive attention recently. One of critical problems in such networks is the energy efficiency, because wireless nodes are usually powered by battery. Energy efficiency design can dramatically increase the survivability and stability of wireless ad-hoc/sensor networks. In this thesis the energy efficiency has been considered at different protocol layers for wireless ad-hoc/sensor networks. The energy consumption of wireless nodes is inspected at the physical layer and MAC layer. At the network layer, some current routing protocols are compared and special attention has been paid to reactive routing protocols. A minimum hop analysis is given and according to the analysis result, a modification of AODV routing is proposed. A variation of transmit power can be also applied to clustering algorithm, which is believed to be able to control the scalability of network. Clustering a network can also improve the energy efficiency. We offer a clustering scheme based on the link state measurement and variation of transmit power of intra-cluster and inter-cluster transmission. Simulation shows that it can achieve both targets. In association with the clustering algorithm, a global synchronization scheme is proposed to increase the efficiency of clustering algorithm. The research attention has been also paid to self-organization for multi-hop cellular networks. A 2-hop 2-slot uplink proposal to infrastructure-based cellular networks. The proposed solution can significantly increase the throughput of uplink communication and reduce the energy consumption of wireless terminals. (orig.)

  4. Microbial electrolytic disinfection process for highly efficient Escherichia coli inactivation

    DEFF Research Database (Denmark)

    Zhou, Shaofeng; Huang, Shaobin; Li, Xiaohu

    2018-01-01

    extensively studied for recalcitrant organics removal, its application potential towards water disinfection (e.g., inactivation of pathogens) is still unknown. This study investigated the inactivation of Escherichia coli in a microbial electrolysis cell based bio-electro-Fenton system (renamed as microbial......Water quality deterioration caused by a wide variety of recalcitrant organics and pathogenic microorganisms has become a serious concern worldwide. Bio-electro-Fenton systems have been considered as cost-effective and highly efficient water treatment platform technology. While it has been......]OH was identified as one potential mechanism for disinfection. This study successfully demonstrated the feasibility of bio-electro-Fenton process for pathogens inactivation, which offers insight for the future development of sustainable, efficient, and cost-effective biological water treatment technology....

  5. Highly Efficient Compression Algorithms for Multichannel EEG.

    Science.gov (United States)

    Shaw, Laxmi; Rahman, Daleef; Routray, Aurobinda

    2018-05-01

    The difficulty associated with processing and understanding the high dimensionality of electroencephalogram (EEG) data requires developing efficient and robust compression algorithms. In this paper, different lossless compression techniques of single and multichannel EEG data, including Huffman coding, arithmetic coding, Markov predictor, linear predictor, context-based error modeling, multivariate autoregression (MVAR), and a low complexity bivariate model have been examined and their performances have been compared. Furthermore, a high compression algorithm named general MVAR and a modified context-based error modeling for multichannel EEG have been proposed. The resulting compression algorithm produces a higher relative compression ratio of 70.64% on average compared with the existing methods, and in some cases, it goes up to 83.06%. The proposed methods are designed to compress a large amount of multichannel EEG data efficiently so that the data storage and transmission bandwidth can be effectively used. These methods have been validated using several experimental multichannel EEG recordings of different subjects and publicly available standard databases. The satisfactory parametric measures of these methods, namely percent-root-mean square distortion, peak signal-to-noise ratio, root-mean-square error, and cross correlation, show their superiority over the state-of-the-art compression methods.

  6. Production and efficiency of organic compost generated by millipede activity

    Directory of Open Access Journals (Sweden)

    Luiz Fernando de Sousa Antunes

    2016-05-01

    Full Text Available ABSTRACT: The putrefactive activity of organisms such as diplopods in the edaphic macrof auna can be leveraged to promote the transformation of agricultural and urban waste into a low-cost substrate for the production of vegetable seedlings. This research aimed to evaluate: (1 the quantity of Gervais millipedes ( Trigoniulus corallinus needed to produce an acceptable quantity of organic compost; (2 the main physical and chemical characteristics of different compost types; and (3 compost efficiency in the production of lettuce seedlings. The first experiment lasted 90 days and was conducted using 6.5L of Gliricidia, 6.5L of Flemingia, 13.5L of grass cuttings, 4.5L of cardboard, 4.5L of coconut husk, and 4.5L of corncob. Treatments consisting of 0, 0.10, 0.30, 0.50, and 0.90L of millipedes were applied. This experiment compared millicompost and vermicompost, using four repetitions. After 23 days, the heights of grown lettuce plants and the weights of the fresh and dry mass of above ground lettuce and of the roots were assessed. A millipede volume of 0.1L proved to be sufficient for the production of an acceptable volume of organic compost. However, the addition of greater volumes leads to increased calcium, magnesium, and phosphorous content. Millicompost has similar physicochemical characteristics those of vermicompost, and both are equally efficient as a substrate for the production of lettuce seedlings.

  7. High efficiency double sided solar cells

    International Nuclear Information System (INIS)

    Seddik, M.M.

    1990-06-01

    Silicon technology state of the art for single crystalline was given to be limited to less than 20% efficiency. A proposed new form of photovoltaic solar cell of high current high efficiency with double sided structures has been given. The new forms could be n ++ pn ++ or p ++ np ++ double side junctions. The idea of double sided devices could be understood as two solar cells connected back-to-back in parallel electrical connection, in which the current is doubled if the cell is illuminated from both sides by a V-shaped reflector. The cell is mounted to the reflector such that each face is inclined at an angle of 45 deg. C to each side of the reflector. The advantages of the new structure are: a) High power devices. b) Easy to fabricate. c) The cells are used vertically instead of horizontal use of regular solar cell which require large area to install. This is very important in power stations and especially for satellite installation. If the proposal is made real and proved to be experimentally feasible, it would be a new era for photovoltaic solar cells since the proposal has already been extended to even higher currents. The suggested structures could be stated as: n ++ pn ++ Vp ++ np ++ ;n ++ pn ++ Vn ++ pn ++ ORp ++ np ++ Vp ++ np ++ . These types of structures are formed in wedged shape to employ indirect illumination by either parabolic; conic or V-shaped reflectors. The advantages of these new forms are low cost; high power; less in size and space; self concentrating; ... etc. These proposals if it happens to find their ways to be achieved experimentally, I think they will offer a short path to commercial market and would have an incredible impact on solar cell technology and applications. (author). 12 refs, 5 figs

  8. Simple Motor Control Concept Results High Efficiency at High Velocities

    Science.gov (United States)

    Starin, Scott; Engel, Chris

    2013-09-01

    The need for high velocity motors in space applications for reaction wheels and detectors has stressed the limits of Brushless Permanent Magnet Motors (BPMM). Due to inherent hysteresis core losses, conventional BPMMs try to balance the need for torque verses hysteresis losses. Cong-less motors have significantly less hysteresis losses but suffer from lower efficiencies. Additionally, the inherent low inductance in cog-less motors result in high ripple currents or high switching frequencies, which lowers overall efficiency and increases performance demands on the control electronics.However, using a somewhat forgotten but fully qualified technology of Isotropic Magnet Motors (IMM), extremely high velocities may be achieved at low power input using conventional drive electronics. This paper will discuss the trade study efforts and empirical test data on a 34,000 RPM IMM.

  9. High Efficiency, Illumination Quality OLEDs for Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Joseph Shiang; James Cella; Kelly Chichak; Anil Duggal; Kevin Janora; Chris Heller; Gautam Parthasarathy; Jeffery Youmans; Joseph Shiang

    2008-03-31

    The goal of the program was to demonstrate a 45 lumen per watt white light device based upon the use of multiple emission colors through the use of solution processing. This performance level is a dramatic extension of the team's previous 15 LPW large area illumination device. The fundamental material system was based upon commercial polymer materials. The team was largely able to achieve these goals, and was able to deliver to DOE a 90 lumen illumination source that had an average performance of 34 LPW a 1000 cd/m{sup 2} with peak performances near 40LPW. The average color temperature is 3200K and the calculated CRI 85. The device operated at a brightness of approximately 1000cd/m{sup 2}. The use of multiple emission colors particularly red and blue, provided additional degrees of design flexibility in achieving white light, but also required the use of a multilayered structure to separate the different recombination zones and prevent interconversion of blue emission to red emission. The use of commercial materials had the advantage that improvements by the chemical manufacturers in charge transport efficiency, operating life and material purity could be rapidly incorporated without the expenditure of additional effort. The program was designed to take maximum advantage of the known characteristics of these material and proceeded in seven steps. (1) Identify the most promising materials, (2) assemble them into multi-layer structures to control excitation and transport within the OLED, (3) identify materials development needs that would optimize performance within multilayer structures, (4) build a prototype that demonstrates the potential entitlement of the novel multilayer OLED architecture (5) integrate all of the developments to find the single best materials set to implement the novel multilayer architecture, (6) further optimize the best materials set, (7) make a large area high illumination quality white OLED. A photo of the final deliverable is shown

  10. Partition efficiencies of newly fabricated universal high-speed counter-current chromatograph for separation of two different types of sugar derivatives with organic-aqueous two-phase solvent systems

    Science.gov (United States)

    Shinomiya, Kazufusa; Sato, Kazuki; Yoshida, Kazunori; Tokura, Koji; Maruyama, Hiroshi; Yanagidaira, Kazuhiro; Ito, Yoichiro

    2013-01-01

    Universal high-speed counter-current chromatograph (HSCCC) was newly designed and fabricated in our laboratory. It holds a set of four column holders symmetrically around the rotary frame at a distance of 11.2 cm from the central axis. By engaging the stationary gear on the central axis of the centrifuge to the planetary gears on the column holder shaft through a set of idle gears, two pairs of diagonally located column holders simultaneously rotate about their own axes in the opposite directions: one forward (type-J planetary motion) and the other backward (type-I planetary motion) each synchronously with the revolution. Using the eccentric coil assembly, partition efficiencies produced by these two planetary motions were compared on the separation of two different types of sugar derivatives (4-methylumbelliferyl and 5-bromo-4-chloro-3-indoxyl sugar derivatives) using organic-aqueous two-phase solvent systems composed of n-hexane/ethyl acetate/1-butanol/methanol/water and aqueous 0.1 M sodium tetraborate, respectively. With lower phase mobile, better peak resolution was obtained by the type-J forward rotation for both samples probably due to higher retention of the stationary phase. With upper phase mobile, however, similar peak resolutions were obtained between these two planetary motions for both sugar derivatives. The overall results indicate that the present universal HSCCC is useful for counter-current chromatographic separation since each planetary motion has its specific applications: e.g., vortex CCC by the type-I planetary motion and HSCCC by the type-J planetary motion both for separation of various natural and synthetic products. PMID:24267319

  11. Efficiency optimization potential in supercritical Organic Rankine Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, A.; Aumann, R. [Technische Universitaet Muenchen Institute of Energy Systems Boltzmannstr. 15, 85748 Garching (Germany); Karellas, S. [National Technical University of Athens Laboratory of Steam Boilers and Thermal Plants Heroon Polytechniou 9, 15780 Athens (Greece)

    2010-02-15

    Nowadays, the use of Organic Rankine Cycle (ORC) in decentralised applications is linked with the fact that this process allows the use of low temperature heat sources and offers an advantageous efficiency in small-scale concepts. Many state-of-the-art and innovative applications can successfully use the ORC process. In this process, according to the heat source level, special attention must be drawn to the choice of the appropriate working fluid, which is a factor that affects the thermal and exergetic efficiency of the cycle. The investigation of supercritical parameters of various working fluids in ORC applications seems to bring promising results concerning the efficiency of the application. This paper presents the results from a simulation of the ORC and the optimization potential of the process when using supercritical parameters. In order to optimize the process, various working fluids are considered and compared concerning their thermal efficiency and the usable percentage of heat. The reduction of exergy losses is discussed based on the need of surplus heat exchanger surface. (author)

  12. High efficiency thin-film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Hans-Werner [Helmholtz Zentrum Berlin (Germany). Solar Energy

    2012-11-01

    Production of photovoltaics is growing worldwide on a gigawatt scale. Among the thin film technologies, Cu(In,Ga)S,Se{sub 2} (CIS or CIGS) based solar cells have been the focus of more and more attention. This paper aims to analyze the success of CIGS based solar cells and the potential of this technology for future photovoltaics large-scale production. Specific material properties make CIS unique and allow the preparation of the material with a wide range of processing options. The huge potential lies in the possibility to take advantage of modern thin film processing equipment and combine it with very high efficiencies beyond 20% already achieved on the laboratory scale. A sustainable development of this technology could be realized by modifying the materials and replacing indium by abundant elements. (orig.)

  13. Design of High Efficient MPPT Solar Inverter

    Directory of Open Access Journals (Sweden)

    Sunitha K. A.

    2017-01-01

    Full Text Available This work aims to design a High Efficient Maximum Power Point Tracking (MPPT Solar Inverter. A boost converter is designed in the system to boost the power from the photovoltaic panel. By this experimental setup a room consisting of 500 Watts load (eight fluorescent tubes is completely controlled. It is aimed to decrease the maintenance cost. A microcontroller is introduced for tracking the P&O (Perturb and Observe algorithm used for tracking the maximum power point. The duty cycle for the operation of the boost convertor is optimally adjusted by using MPPT controller. There is a MPPT charge controller to charge the battery as well as fed to inverter which runs the load. Both the P&O scheme with the fixed variation for the reference current and the intelligent MPPT algorithm were able to identify the global Maximum power point, however the performance of the MPPT algorithm was better.

  14. High Efficiency Ka-Band Spatial Combiner

    Directory of Open Access Journals (Sweden)

    D. Passi

    2014-12-01

    Full Text Available A Ka-Band, High Efficiency, Small Size Spatial Combiner (SPC is proposed in this paper, which uses an innovatively matched quadruple Fin Lines to microstrip (FLuS transitions. At the date of this paper and at the Author's best knowledge no such FLuS innovative transitions have been reported in literature before. These transitions are inserted into a WR28 waveguide T-junction, in order to allow the integration of 16 Monolithic Microwave Integrated Circuit (MMIC Solid State Power Amplifiers (SSPA's. A computational electromagnetic model using the finite elements method has been implemented. A mean insertion loss of 2 dB is achieved with a return loss better the 10 dB in the 31-37 GHz bandwidth.

  15. Multi-petascale highly efficient parallel supercomputer

    Science.gov (United States)

    Asaad, Sameh; Bellofatto, Ralph E.; Blocksome, Michael A.; Blumrich, Matthias A.; Boyle, Peter; Brunheroto, Jose R.; Chen, Dong; Cher, Chen-Yong; Chiu, George L.; Christ, Norman; Coteus, Paul W.; Davis, Kristan D.; Dozsa, Gabor J.; Eichenberger, Alexandre E.; Eisley, Noel A.; Ellavsky, Matthew R.; Evans, Kahn C.; Fleischer, Bruce M.; Fox, Thomas W.; Gara, Alan; Giampapa, Mark E.; Gooding, Thomas M.; Gschwind, Michael K.; Gunnels, John A.; Hall, Shawn A.; Haring, Rudolf A.; Heidelberger, Philip; Inglett, Todd A.; Knudson, Brant L.; Kopcsay, Gerard V.; Kumar, Sameer; Mamidala, Amith R.; Marcella, James A.; Megerian, Mark G.; Miller, Douglas R.; Miller, Samuel J.; Muff, Adam J.; Mundy, Michael B.; O'Brien, John K.; O'Brien, Kathryn M.; Ohmacht, Martin; Parker, Jeffrey J.; Poole, Ruth J.; Ratterman, Joseph D.; Salapura, Valentina; Satterfield, David L.; Senger, Robert M.; Steinmacher-Burow, Burkhard; Stockdell, William M.; Stunkel, Craig B.; Sugavanam, Krishnan; Sugawara, Yutaka; Takken, Todd E.; Trager, Barry M.; Van Oosten, James L.; Wait, Charles D.; Walkup, Robert E.; Watson, Alfred T.; Wisniewski, Robert W.; Wu, Peng

    2018-05-15

    A Multi-Petascale Highly Efficient Parallel Supercomputer of 100 petaflop-scale includes node architectures based upon System-On-a-Chip technology, where each processing node comprises a single Application Specific Integrated Circuit (ASIC). The ASIC nodes are interconnected by a five dimensional torus network that optimally maximize the throughput of packet communications between nodes and minimize latency. The network implements collective network and a global asynchronous network that provides global barrier and notification functions. Integrated in the node design include a list-based prefetcher. The memory system implements transaction memory, thread level speculation, and multiversioning cache that improves soft error rate at the same time and supports DMA functionality allowing for parallel processing message-passing.

  16. The CRRES high efficiency solar panel

    International Nuclear Information System (INIS)

    Trumble, T.M.

    1991-01-01

    This paper reports on the High Efficiency Solar Panel (HESP) experiments which is to provide both engineering and scientific information concerning the effects of space radiation on advanced gallium arsenide (GaAs) solar cells. The HESP experiment consists of an ambient panel, and annealing panel and a programmable load. This experiment, in conjunction with the radiation measurement experiments abroad the CREES, provides the first opportunity to simultaneously measure the trapped radiation belts and the results of radiation damage to solar cells. The engineering information will result in a design guide for selecting the optimum solar array characteristics for different orbits and different lifetimes. The scientific information will provide both correlation of laboratory damage effects to space damage effects and a better model for predicting effective solar cell panel lifetimes

  17. Carbon nanotube-supported Au-Pd alloy with cooperative effect of metal nanoparticles and organic ketone/quinone groups as a highly efficient catalyst for aerobic oxidation of amines.

    Science.gov (United States)

    Deng, Weiping; Chen, Jiashu; Kang, Jincan; Zhang, Qinghong; Wang, Ye

    2016-05-21

    Functionalised carbon nanotube (CNT)-supported Au-Pd alloy nanoparticles were highly efficient catalysts for the aerobic oxidation of amines. We achieved the highest turnover frequencies (>1000 h(-1)) for the oxidative homocoupling of benzylamine and the oxidative dehydrogenation of dibenzylamine. We discovered a cooperative effect between Au-Pd nanoparticles and ketone/quinone groups on CNTs.

  18. Towards low cost, efficient and stable organic photovoltaic modules

    NARCIS (Netherlands)

    Andriessen, H.A.J.M.; Galagan, Y.O.; Rubingh, J.E.J.M.; Grossiord, N.; Blom, P.W.M.; Kroon, J.; Veenstra, S.; Verhees, W.; Slooff, L.; Pex, P.

    2010-01-01

    The presence of a transparent conductive electrode such as indium tin oxide (ITO) limits the reliability and cost price of organic photovoltaic devices as it is brittle and expensive. Moreover, the relative high sheet resistance of an ITO electrode on flexible substrates limits the maximum width of

  19. Power efficiency of mineral and organic fertilizers application in crop rotations

    OpenAIRE

    BOSAK V.M.

    2009-01-01

    In researches on sod podzolic light loamy soil the application of mineral and organic fertilizers has provided high indicators of agronomic and power efficiency. Entering of mineral fertilizers has raised efficiency of field crop rotations on 19,9-30,3 tha -1 of f.u., as well as entering of organic fertilizers on 5,2-10,8 tha -1 of f.u. at a recoupment of 1 ton of manure of 65,0-131,3 f.u. and 1 kg of NPK of 8,1-9,7 f.u. Power return of application of mineral fertilizers in crop rotations has...

  20. Zerodur polishing process for high surface quality and high efficiency

    International Nuclear Information System (INIS)

    Tesar, A.; Fuchs, B.

    1992-08-01

    Zerodur is a glass-ceramic composite importance in applications where temperature instabilities influence optical and mechanical performance, such as in earthbound and spaceborne telescope mirror substrates. Polished Zerodur surfaces of high quality have been required for laser gyro mirrors. Polished surface quality of substrates affects performance of high reflection coatings. Thus, the interest in improving Zerodur polished surface quality has become more general. Beyond eliminating subsurface damage, high quality surfaces are produced by reducing the amount of hydrated material redeposited on the surface during polishing. With the proper control of polishing parameters, such surfaces exhibit roughnesses of < l Angstrom rms. Zerodur polishing was studied to recommend a high surface quality polishing process which could be easily adapted to standard planetary continuous polishing machines and spindles. This summary contains information on a polishing process developed at LLNL which reproducibly provides high quality polished Zerodur surfaces at very high polishing efficiencies

  1. Flexible organic solar cells including efficiency enhancing grating structures

    International Nuclear Information System (INIS)

    De Oliveira Hansen, Roana Melina; Liu Yinghui; Madsen, Morten; Rubahn, Horst-Günter

    2013-01-01

    In this work, a new method for the fabrication of organic solar cells containing functional light-trapping nanostructures on flexible substrates is presented. Polyimide is spin-coated on silicon support substrates, enabling standard micro- and nanotechnology fabrication techniques, such as photolithography and electron-beam lithography, besides the steps required for the bulk-heterojunction organic solar cell fabrication. After the production steps, the solar cells on polyimide are peeled off the silicon support substrates, resulting in flexible devices containing nanostructures for light absorption enhancement. Since the solar cells avoid using brittle electrodes, the performance of the flexible devices is not affected by the peeling process. We have investigated three different nanostructured grating designs and conclude that gratings with a 500 nm pitch distance have the highest light-trapping efficiency for the selected active layer material (P3HT:PCBM), resulting in an enhancement of about 34% on the solar cell efficiency. The presented method can be applied to a large variety of flexible nanostructured devices in future applications. (paper)

  2. Efficient white organic light emission by single emitting layer

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Young Wook; Chung, Choong-Heui; Lee, Jin Ho; Kim, Yong-Hae; Sohn, Choong-Yong; Kim, Bong-Chul; Hwang, Chi-Sun; Song, Yoon-Ho; Lim, Jongtae; Ahn, Young-Joo; Kang, Gi-Wook; Lee, Namheon; Lee, Changhee

    2003-02-24

    Stable organic white light-emitting diodes are successfully fabricated by a single organic white emitting layer, which is Bis (2-methyl-8-quinolinato) (triphenylsiloxy) aluminum (III) (SAlq) doped red fluorescent dye of 4-(dicyanomethylene)-2-tert-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)- 4H-pyran (DCJTB). The incomplete energy transfer from blue-emitting SAlq to red-emitting DCJTB enables to obtain a stable white balanced light-emission by the DCJTB doping concentration of 0.5%. A device with the structure of ITO/TPD (50 nm)/SAlq:DCJTB (30 nm, 0.5%)/Alq{sub 3} (20 nm)/LiF (0.5 nm)/Al (110 nm) shows maximum luminance of 20 400 cd/m{sup 2} at 810 mA/cm{sup 2}, external quantum efficiency of 2% at 200 cd/m{sup 2} ({approx}3 mA/cm{sup 2}), power efficiency of 2.3 lm/W at 67 cd/m{sup 2} ({approx}1 mA/cm{sup 2}), and a Commission Internationale de l'Eclairage chromaticity coordinates of (0.34, 0.39) at 1.8 mA/cm{sup 2} to (0.31, 0.38) at 36 mA/cm{sup 2}.

  3. Highly Simplified Reddish Orange Phosphorescent Organic Light-Emitting Diodes Incorporating a Novel Carrier- and Exciton-Confining Spiro-Exciplex-Forming Host for Reduced Efficiency Roll-off.

    Science.gov (United States)

    Xu, Ting; Zhang, Ye-Xin; Wang, Bo; Huang, Chen-Chao; Murtaza, Imran; Meng, Hong; Liao, Liang-Sheng

    2017-01-25

    A novel exciplex-forming host is applied so as to design highly simplified reddish orange light-emitting diodes (OLEDs) with low driving voltage, high efficiency, and an extraordinarily low efficiency roll-off, by combining N,N-10-triphenyl-10H-spiro [acridine-9,9'-fluoren]-3'-amine (SAFDPA) with 4,7-diphenyl-1,10-phenanthroline (Bphen) doped with trivalent iridium complex bis(2-methyldibenzo[f,h]quinoxaline) (acetylacetonate)iridium(III) (Ir(MDQ) 2 (acac)). The reddish orange OLEDs achieve a strikingly high power efficiency (PE) of 31.80 lm/W with an ultralow threshold voltage of 2.24 V which is almost equal to the triplet energy level of the phosphorescent reddish orange emitting dopant. The power efficiency of the device with the exciplex-forming host is enhanced, achieving 36.2% mainly owing to the lower operating voltage by the novel exciplex forming cohost, compared with the reference device (23.54 lm/W). Moreover, the OLEDs show extraordinarily low current efficiency (CE) roll-off to 1.41% at the brightness from 500 to 5000 cd/m 2 with a maximal CE of 32.87 cd/A (EQE max = 11.01%). The devices display a good reddish orange color (CIE of (0.628, 0.372) at 500 cd/m 2 ) nearly without color shift with increasing brightness. Co-host architecture phosphorescent OLEDs show a simpler device structure, lower working voltage, and a better efficiency and stability than those of the reference devices without the cohost architecture, which helps to simplify the OLED structure, lower the cost, and popularize OLED technology.

  4. Highly efficient red electrophosphorescent devices at high current densities

    International Nuclear Information System (INIS)

    Wu Youzhi; Zhu Wenqing; Zheng Xinyou; Sun, Runguang; Jiang Xueyin; Zhang Zhilin; Xu Shaohong

    2007-01-01

    Efficiency decrease at high current densities in red electrophosphorescent devices is drastically restrained compared with that from conventional electrophosphorescent devices by using bis(2-methyl-8-quinolinato)4-phenylphenolate aluminum (BAlq) as a hole and exciton blocker. Ir complex, bis(2-(2'-benzo[4,5-α]thienyl) pyridinato-N,C 3' ) iridium (acetyl-acetonate) is used as an emitter, maximum external quantum efficiency (QE) of 7.0% and luminance of 10000cd/m 2 are obtained. The QE is still as high as 4.1% at higher current density J=100mA/cm 2 . CIE-1931 co-ordinates are 0.672, 0.321. A carrier trapping mechanism is revealed to dominate in the process of electroluminescence

  5. White LED with High Package Extraction Efficiency

    International Nuclear Information System (INIS)

    Yi Zheng; Stough, Matthew

    2008-01-01

    The goal of this project is to develop a high efficiency phosphor converting (white) Light Emitting Diode (pcLED) 1-Watt package through an increase in package extraction efficiency. A transparent/translucent monolithic phosphor is proposed to replace the powdered phosphor to reduce the scattering caused by phosphor particles. Additionally, a multi-layer thin film selectively reflecting filter is proposed between blue LED die and phosphor layer to recover inward yellow emission. At the end of the project we expect to recycle approximately 50% of the unrecovered backward light in current package construction, and develop a pcLED device with 80 lm/W e using our technology improvements and commercially available chip/package source. The success of the project will benefit luminous efficacy of white LEDs by increasing package extraction efficiency. In most phosphor-converting white LEDs, the white color is obtained by combining a blue LED die (or chip) with a powdered phosphor layer. The phosphor partially absorbs the blue light from the LED die and converts it into a broad green-yellow emission. The mixture of the transmitted blue light and green-yellow light emerging gives white light. There are two major drawbacks for current pcLEDs in terms of package extraction efficiency. The first is light scattering caused by phosphor particles. When the blue photons from the chip strike the phosphor particles, some blue light will be scattered by phosphor particles. Converted yellow emission photons are also scattered. A portion of scattered light is in the backward direction toward the die. The amount of this backward light varies and depends in part on the particle size of phosphors. The other drawback is that yellow emission from phosphor powders is isotropic. Although some backward light can be recovered by the reflector in current LED packages, there is still a portion of backward light that will be absorbed inside the package and further converted to heat. Heat generated

  6. Tailored Materials for High Efficiency CIDI Engines

    Energy Technology Data Exchange (ETDEWEB)

    Grant, G.J.; Jana, S.

    2012-03-30

    The overall goal of the project, Tailored Materials for High Efficiency Compression Ignition Direct Injection (CIDI) Engines, is to enable the implementation of new combustion strategies, such as homogeneous charge compression ignition (HCCI), that have the potential to significantly increase the energy efficiency of current diesel engines and decrease fuel consumption and environmental emissions. These strategies, however, are increasing the demands on conventional engine materials, either from increases in peak cylinder pressure (PCP) or from increases in the temperature of operation. The specific objective of this project is to investigate the application of a new material processing technology, friction stir processing (FSP), to improve the thermal and mechanical properties of engine components. The concept is to modify the surfaces of conventional, low-cost engine materials. The project focused primarily on FSP in aluminum materials that are compositional analogs to the typical piston and head alloys seen in small- to mid-sized CIDI engines. Investigations have been primarily of two types over the duration of this project: (1) FSP of a cast hypoeutectic Al-Si-Mg (A356/357) alloy with no introduction of any new components, and (2) FSP of Al-Cu-Ni alloys (Alloy 339) by physically stirring-in various quantities of carbon nanotubes/nanofibers or carbon fibers. Experimental work to date on aluminum systems has shown significant increases in fatigue lifetime and stress-level performance in aluminum-silicon alloys using friction processing alone, but work to demonstrate the addition of carbon nanotubes and fibers into aluminum substrates has shown mixed results due primarily to the difficulty in achieving porosity-free, homogeneous distributions of the particulate. A limited effort to understand the effects of FSP on steel materials was also undertaken during the course of this project. Processed regions were created in high-strength, low-alloyed steels up to 0.5 in

  7. High efficiency diffusion molecular retention tumor targeting.

    Directory of Open Access Journals (Sweden)

    Yanyan Guo

    Full Text Available Here we introduce diffusion molecular retention (DMR tumor targeting, a technique that employs PEG-fluorochrome shielded probes that, after a peritumoral (PT injection, undergo slow vascular uptake and extensive interstitial diffusion, with tumor retention only through integrin molecular recognition. To demonstrate DMR, RGD (integrin binding and RAD (control probes were synthesized bearing DOTA (for (111 In(3+, a NIR fluorochrome, and 5 kDa PEG that endows probes with a protein-like volume of 25 kDa and decreases non-specific interactions. With a GFP-BT-20 breast carcinoma model, tumor targeting by the DMR or i.v. methods was assessed by surface fluorescence, biodistribution of [(111In] RGD and [(111In] RAD probes, and whole animal SPECT. After a PT injection, both probes rapidly diffused through the normal and tumor interstitium, with retention of the RGD probe due to integrin interactions. With PT injection and the [(111In] RGD probe, SPECT indicated a highly tumor specific uptake at 24 h post injection, with 352%ID/g tumor obtained by DMR (vs 4.14%ID/g by i.v.. The high efficiency molecular targeting of DMR employed low probe doses (e.g. 25 ng as RGD peptide, which minimizes toxicity risks and facilitates clinical translation. DMR applications include the delivery of fluorochromes for intraoperative tumor margin delineation, the delivery of radioisotopes (e.g. toxic, short range alpha emitters for radiotherapy, or the delivery of photosensitizers to tumors accessible to light.

  8. High collection efficiency CVD diamond alpha detectors

    International Nuclear Information System (INIS)

    Bergonzo, P.; Foulon, F.; Marshall, R.D.; Jany, C.; Brambilla, A.; McKeag, R.D.; Jackman, R.B.

    1998-01-01

    Advances in Chemical Vapor Deposited (CVD) diamond have enabled the routine use of this material for sensor device fabrication, allowing exploitation of its unique combination of physical properties (low temperature susceptibility (> 500 C), high resistance to radiation damage (> 100 Mrad) and to corrosive media). A consequence of CVD diamond growth on silicon is the formation of polycrystalline films which has a profound influence on the physical and electronic properties with respect to those measured on monocrystalline diamond. The authors report the optimization of physical and geometrical device parameters for radiation detection in the counting mode. Sandwich and co-planar electrode geometries are tested and their performances evaluated with regard to the nature of the field profile and drift distances inherent in such devices. The carrier drift length before trapping was measured under alpha particles and values as high as 40% of the overall film thickness are reported. Further, by optimizing the device geometry, they show that a gain in collection efficiency, defined as the induced charge divided by the deposited charge within the material, can be achieved even though lower bias values are used

  9. High bandgap III-V alloys for high efficiency optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Alberi, Kirstin; Mascarenhas, Angelo; Wanlass, Mark

    2017-01-10

    High bandgap alloys for high efficiency optoelectronics are disclosed. An exemplary optoelectronic device may include a substrate, at least one Al.sub.1-xIn.sub.xP layer, and a step-grade buffer between the substrate and at least one Al.sub.1-xIn.sub.xP layer. The buffer may begin with a layer that is substantially lattice matched to GaAs, and may then incrementally increase the lattice constant in each sequential layer until a predetermined lattice constant of Al.sub.1-xIn.sub.xP is reached.

  10. Performance of a high efficiency high power UHF klystron

    International Nuclear Information System (INIS)

    Konrad, G.T.

    1977-03-01

    A 500 kW c-w klystron was designed for the PEP storage ring at SLAC. The tube operates at 353.2 MHz, 62 kV, a microperveance of 0.75, and a gain of approximately 50 dB. Stable operation is required for a VSWR as high as 2 : 1 at any phase angle. The design efficiency is 70%. To obtain this value of efficiency, a second harmonic cavity is used in order to produce a very tightly bunched beam in the output gap. At the present time it is planned to install 12 such klystrons in PEP. A tube with a reduced size collector was operated at 4% duty at 500 kW. An efficiency of 63% was observed. The same tube was operated up to 200 kW c-w for PEP accelerator cavity tests. A full-scale c-w tube reached 500 kW at 65 kV with an efficiency of 55%. In addition to power and phase measurements into a matched load, some data at various load mismatches are presented

  11. Fine-Tuning the Energy Levels of a Nonfullerene Small-Molecule Acceptor to Achieve a High Short-Circuit Current and a Power Conversion Efficiency over 12% in Organic Solar Cells.

    Science.gov (United States)

    Kan, Bin; Zhang, Jiangbin; Liu, Feng; Wan, Xiangjian; Li, Chenxi; Ke, Xin; Wang, Yunchuang; Feng, Huanran; Zhang, Yamin; Long, Guankui; Friend, Richard H; Bakulin, Artem A; Chen, Yongsheng

    2018-01-01

    Organic solar cell optimization requires careful balancing of current-voltage output of the materials system. Here, such optimization using ultrafast spectroscopy as a tool to optimize the material bandgap without altering ultrafast photophysics is reported. A new acceptor-donor-acceptor (A-D-A)-type small-molecule acceptor NCBDT is designed by modification of the D and A units of NFBDT. Compared to NFBDT, NCBDT exhibits upshifted highest occupied molecular orbital (HOMO) energy level mainly due to the additional octyl on the D unit and downshifted lowest unoccupied molecular orbital (LUMO) energy level due to the fluorination of A units. NCBDT has a low optical bandgap of 1.45 eV which extends the absorption range toward near-IR region, down to ≈860 nm. However, the 60 meV lowered LUMO level of NCBDT hardly changes the V oc level, and the elevation of the NCBDT HOMO does not have a substantial influence on the photophysics of the materials. Thus, for both NCBDT- and NFBDT-based systems, an unusually slow (≈400 ps) but ultimately efficient charge generation mediated by interfacial charge-pair states is observed, followed by effective charge extraction. As a result, the PBDB-T:NCBDT devices demonstrate an impressive power conversion efficiency over 12%-among the best for solution-processed organic solar cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. ECONOMIC EFFICIENCY ANALYSIS OF ORGANIC CROP AND ANIMAL FARMS IN ROMANIA. COMPARATIVE EVOLUTIONS

    Directory of Open Access Journals (Sweden)

    Alexandra MUSCĂNESCU

    2013-10-01

    Full Text Available The organic sector in our country, although as shown in continuous development, faces a multitude of problems: the climatic conditions of our country, characterized by periods of drought in many parts of the country, high input prices, the majority of which are imported; difficulties in identifying markets for products, reduced subsidies, standardized conditions difficult to meet, etc. The problems the sector is facing reflect in the organization of the production activity and hence the economic performance of farm production. Accordingly, the aim of this paper was to analyze on the basis of annual financial and accounting information collected in the two vegetable farms and the two animal breeding farms, their efficiency / inefficiency, and the results were compared to identify the causes of the differences obtained in the efficiency at a farm level. The results obtained reveal a higher level of return on integrated vegetable farm in a joint recovery and a high efficiency for chain integrated animal farms.

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

    International Nuclear Information System (INIS)

    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.

  14. Series-Tuned High Efficiency RF-Power Amplifiers

    DEFF Research Database (Denmark)

    Vidkjær, Jens

    2008-01-01

    An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits.......An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits....

  15. Ultra-efficient all-printed organic photodetectors

    Science.gov (United States)

    Kielar, Marcin; Dhez, Olivier; Hirsch, Lionel

    2016-09-01

    Organic photodetectors are able to transform plastic into intelligent surfaces making our daily life easier, smarter and more productive. The key element for a sensor is to reduce the dark current density in order to boost the limit of detection. The energetic requirements in order to select materials for ultra-high performance organic photodetectors are presented with the following experimental results: a detectivity of 3.36 × 1013 Jones has been achieved with an extremely low dark current density of 0.32 nA cm-2 and a responsivity as high as 0.34 A W-1. Flexible devices are all made at lowtemperature and with solution-processed materials. Their stability under operation is also presented.

  16. Multi-petascale highly efficient parallel supercomputer

    Science.gov (United States)

    Asaad, Sameh; Bellofatto, Ralph E.; Blocksome, Michael A.; Blumrich, Matthias A.; Boyle, Peter; Brunheroto, Jose R.; Chen, Dong; Cher, Chen -Yong; Chiu, George L.; Christ, Norman; Coteus, Paul W.; Davis, Kristan D.; Dozsa, Gabor J.; Eichenberger, Alexandre E.; Eisley, Noel A.; Ellavsky, Matthew R.; Evans, Kahn C.; Fleischer, Bruce M.; Fox, Thomas W.; Gara, Alan; Giampapa, Mark E.; Gooding, Thomas M.; Gschwind, Michael K.; Gunnels, John A.; Hall, Shawn A.; Haring, Rudolf A.; Heidelberger, Philip; Inglett, Todd A.; Knudson, Brant L.; Kopcsay, Gerard V.; Kumar, Sameer; Mamidala, Amith R.; Marcella, James A.; Megerian, Mark G.; Miller, Douglas R.; Miller, Samuel J.; Muff, Adam J.; Mundy, Michael B.; O'Brien, John K.; O'Brien, Kathryn M.; Ohmacht, Martin; Parker, Jeffrey J.; Poole, Ruth J.; Ratterman, Joseph D.; Salapura, Valentina; Satterfield, David L.; Senger, Robert M.; Smith, Brian; Steinmacher-Burow, Burkhard; Stockdell, William M.; Stunkel, Craig B.; Sugavanam, Krishnan; Sugawara, Yutaka; Takken, Todd E.; Trager, Barry M.; Van Oosten, James L.; Wait, Charles D.; Walkup, Robert E.; Watson, Alfred T.; Wisniewski, Robert W.; Wu, Peng

    2015-07-14

    A Multi-Petascale Highly Efficient Parallel Supercomputer of 100 petaOPS-scale computing, at decreased cost, power and footprint, and that allows for a maximum packaging density of processing nodes from an interconnect point of view. The Supercomputer exploits technological advances in VLSI that enables a computing model where many processors can be integrated into a single Application Specific Integrated Circuit (ASIC). Each ASIC computing node comprises a system-on-chip ASIC utilizing four or more processors integrated into one die, with each having full access to all system resources and enabling adaptive partitioning of the processors to functions such as compute or messaging I/O on an application by application basis, and preferably, enable adaptive partitioning of functions in accordance with various algorithmic phases within an application, or if I/O or other processors are underutilized, then can participate in computation or communication nodes are interconnected by a five dimensional torus network with DMA that optimally maximize the throughput of packet communications between nodes and minimize latency.

  17. Energy Efficient Graphene Based High Performance Capacitors.

    Science.gov (United States)

    Bae, Joonwon; Kwon, Oh Seok; Lee, Chang-Soo

    2017-07-10

    Graphene (GRP) is an interesting class of nano-structured electronic materials for various cutting-edge applications. To date, extensive research activities have been performed on the investigation of diverse properties of GRP. The incorporation of this elegant material can be very lucrative in terms of practical applications in energy storage/conversion systems. Among various those systems, high performance electrochemical capacitors (ECs) have become popular due to the recent need for energy efficient and portable devices. Therefore, in this article, the application of GRP for capacitors is described succinctly. In particular, a concise summary on the previous research activities regarding GRP based capacitors is also covered extensively. It was revealed that a lot of secondary materials such as polymers and metal oxides have been introduced to improve the performance. Also, diverse devices have been combined with capacitors for better use. More importantly, recent patents related to the preparation and application of GRP based capacitors are also introduced briefly. This article can provide essential information for future study. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  18. Singlet fission efficiency in tetracene-based organic solar cells

    International Nuclear Information System (INIS)

    Wu, Tony C.; Thompson, Nicholas J.; Congreve, Daniel N.; Hontz, Eric; Yost, Shane R.; Van Voorhis, Troy; Baldo, Marc A.

    2014-01-01

    Singlet exciton fission splits one singlet exciton into two triplet excitons. Using a joint analysis of photocurrent and fluorescence modulation under a magnetic field, we determine that the triplet yield within optimized tetracene organic photovoltaic devices is 153% ± 5% for a tetracene film thickness of 20 nm. The corresponding internal quantum efficiency is 127% ± 18%. These results are used to prove the effectiveness of a simplified triplet yield measurement that relies only on the magnetic field modulation of fluorescence. Despite its relatively slow rate of singlet fission, the measured triplet yields confirm that tetracene is presently the best candidate for use with silicon solar cells

  19. Highly efficient silicon light emitting diode

    NARCIS (Netherlands)

    Le Minh, P.; Holleman, J.; Wallinga, Hans

    2002-01-01

    In this paper, we describe the fabrication, using standard silicon processing techniques, of silicon light-emitting diodes (LED) that efficiently emit photons with energy around the silicon bandgap. The improved efficiency had been explained by the spatial confinement of charge carriers due to a

  20. A novel high efficiency solar photovoltalic pump

    NARCIS (Netherlands)

    Diepens, J.F.L.; Smulders, P.T.; Vries, de D.A.

    1993-01-01

    The daily average overall efficiency of a solar pump system is not only influenced by the maximum efficiency of the components of the system, but just as much by the correct matching of the components to the local irradiation pattern. Normally centrifugal pumps are used in solar pump systems. The

  1. High efficiency targets for high gain inertial confinement fusion

    International Nuclear Information System (INIS)

    Gardner, J.H.; Bodner, S.E.

    1986-01-01

    Rocket efficiencies as high as 15% are possible using short wavelength lasers and moderately high aspect ratio pellet designs. These designs are made possible by two recent breakthroughs in physics constraints. First is the development of the Induced Spatial Incoherence (ISI) technique which allows uniform illumination of the pellet and relaxes the constraint of thermal smoothing, permitting the use of short wavelength laser light. Second is the discovery that the Rayleigh-Taylor growth rate is considerably reduced at the short laser wavelengths. By taking advantage of the reduced constraints imposed by nonuniform laser illumination and Rayleigh-Taylor instability, pellets using 1/4 micron laser light and initial aspect ratios of about 10 (with in flight aspect ratios of about 150 to 200) may produce energy gains as high as 200 to 250

  2. High power klystrons for efficient reliable high power amplifiers

    Science.gov (United States)

    Levin, M.

    1980-11-01

    This report covers the design of reliable high efficiency, high power klystrons which may be used in both existing and proposed troposcatter radio systems. High Power (10 kW) klystron designs were generated in C-band (4.4 GHz to 5.0 GHz), S-band (2.5 GHz to 2.7 GHz), and L-band or UHF frequencies (755 MHz to 985 MHz). The tubes were designed for power supply compatibility and use with a vapor/liquid phase heat exchanger. Four (4) S-band tubes were developed in the course of this program along with two (2) matching focusing solenoids and two (2) heat exchangers. These tubes use five (5) tuners with counters which are attached to the focusing solenoids. A reliability mathematical model of the tube and heat exchanger system was also generated.

  3. Efficient Flexible Organic/Inorganic Hybrid Perovskite Light-Emitting Diodes Based on Graphene Anode.

    Science.gov (United States)

    Seo, Hong-Kyu; Kim, Hobeom; Lee, Jaeho; Park, Min-Ho; Jeong, Su-Hun; Kim, Young-Hoon; Kwon, Sung-Joo; Han, Tae-Hee; Yoo, Seunghyup; Lee, Tae-Woo

    2017-03-01

    Highly efficient organic/inorganic hybrid perovskite light-emitting diodes (PeLEDs) based on graphene anode are developed for the first time. Chemically inert graphene avoids quenching of excitons by diffused metal atom species from indium tin oxide. The flexible PeLEDs with graphene anode on plastic substrate show good bending stability; they provide an alternative and reliable flexible electrode for highly efficient flexible PeLEDs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Ultrathin nondoped emissive layers for efficient and simple monochrome and white organic light-emitting diodes.

    Science.gov (United States)

    Zhao, Yongbiao; Chen, Jiangshan; Ma, Dongge

    2013-02-01

    In this paper, highly efficient and simple monochrome blue, green, orange, and red organic light emitting diodes (OLEDs) based on ultrathin nondoped emissive layers (EMLs) have been reported. The ultrathin nondoped EML was constructed by introducing a 0.1 nm thin layer of pure phosphorescent dyes between a hole transporting layer and an electron transporting layer. The maximum external quantum efficiencies (EQEs) reached 17.1%, 20.9%, 17.3%, and 19.2% for blue, green, orange, and red monochrome OLEDs, respectively, indicating the universality of the ultrathin nondoped EML for most phosphorescent dyes. On the basis of this, simple white OLED structures are also demonstrated. The demonstrated complementary blue/orange, three primary blue/green/red, and four color blue/green/orange/red white OLEDs show high efficiency and good white emission, indicating the advantage of ultrathin nondoped EMLs on constructing simple and efficient white OLEDs.

  5. High efficiency quasi-monochromatic infrared emitter

    Energy Technology Data Exchange (ETDEWEB)

    Brucoli, Giovanni; Besbes, Mondher; Benisty, Henri, E-mail: henri.benisty@institutoptique.fr; Greffet, Jean-Jacques [Laboratoire Charles Fabry, UMR 8501, Institut d’Optique, CNRS, Université Paris-Sud 11, 2, Avenue Augustin Fresnel, 91127 Palaiseau Cedex (France); Bouchon, Patrick; Haïdar, Riad [Office National d’Études et de Recherches Aérospatiales, Chemin de la Hunière, 91761 Palaiseau (France)

    2014-02-24

    Incandescent radiation sources are widely used as mid-infrared emitters owing to the lack of alternative for compact and low cost sources. A drawback of miniature hot systems such as membranes is their low efficiency, e.g., for battery powered systems. For targeted narrow-band applications such as gas spectroscopy, the efficiency is even lower. In this paper, we introduce design rules valid for very generic membranes demonstrating that their energy efficiency for use as incandescent infrared sources can be increased by two orders of magnitude.

  6. Energy efficiency of high-rise buildings

    Science.gov (United States)

    Zhigulina, Anna Yu.; Ponomarenko, Alla M.

    2018-03-01

    The article is devoted to analysis of tendencies and advanced technologies in the field of energy supply and energy efficiency of tall buildings, to the history of the emergence of the concept of "efficiency" and its current interpretation. Also the article show the difference of evaluation criteria of the leading rating systems LEED and BREEAM. Authors reviewed the latest technologies applied in the construction of energy efficient buildings. Methodological approach to the design of tall buildings taking into account energy efficiency needs to include the primary energy saving; to seek the possibility of production and accumulation of alternative electric energy by converting energy from the sun and wind with the help of special technical devices; the application of regenerative technologies.

  7. High Efficiency Refrigeration Process, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — It has been proposed by NASA JSC studies, that the most mass efficient (non-nuclear) method of Lunar habitat cooling is via photovoltaic (PV) direct vapor...

  8. Rational design and characterization of high-efficiency planar A–π–D–π–A type electron donors in small molecule organic solar cells: A quantum chemical approach

    International Nuclear Information System (INIS)

    Wang, Dongmei; Ding, Weilu; Geng, Zhiyuan; Wang, Li; Geng, Yun; Su, Zhongmin; Yu, Hailing

    2014-01-01

    Taking the reported donor DR3TBDT as reference, a series of A–π–D–π–A type donor molecules involving different planar donor cores were designed and investigated by using density functional theory (DFT)/time-dependent DFT methods. Preliminary calculations on geometries, energy levels and spectrum properties show that four of the designed molecules (4, 5, 12 and 13) could become potential donor replacements of DR3TBDT due to their good planarity, larger light harvesting efficiencies and similar exciton migration capability. Additionally, several factors influencing on short-circuit current density (J sc ) were analyzed by in-depth quantum chemical investigations on the transition density matrix, charge transfer indexes, exciton binding energy and Gibbs free energy loss in charge dissociation process. Comparative analyses demonstrate that 4 with indaceno[1,2-b:5,6-b′]dithiophene donor core has more significant electron transfer character and favorable exciton dissociation capability for enhancing the J sc , and would be potentially promising donor material in organic solar cells. - Graphical abstract: Display Omitted - Highlights: • A series of A–π–D–π–A type donors with different donor core for OSC were designed. • The relationship between donor properties and device performance is explored by DFT. • An In-depth quantum chemical investigation on the affecting factors on J sc . • The efficiency of new donor 4 may surpass the reported donor DR3TBDT

  9. Technical Efficiency and Organ Transplant Performance: A Mixed-Method Approach

    Science.gov (United States)

    de-Pablos-Heredero, Carmen; Fernández-Renedo, Carlos; Medina-Merodio, Jose-Amelio

    2015-01-01

    Mixed methods research is interesting to understand complex processes. Organ transplants are complex processes in need of improved final performance in times of budgetary restrictions. As the main objective a mixed method approach is used in this article to quantify the technical efficiency and the excellence achieved in organ transplant systems and to prove the influence of organizational structures and internal processes in the observed technical efficiency. The results show that it is possible to implement mechanisms for the measurement of the different components by making use of quantitative and qualitative methodologies. The analysis show a positive relationship between the levels related to the Baldrige indicators and the observed technical efficiency in the donation and transplant units of the 11 analyzed hospitals. Therefore it is possible to conclude that high levels in the Baldrige indexes are a necessary condition to reach an increased level of the service offered. PMID:25950653

  10. High Power High Efficiency Diode Laser Stack for Processing

    Science.gov (United States)

    Gu, Yuanyuan; Lu, Hui; Fu, Yueming; Cui, Yan

    2018-03-01

    High-power diode lasers based on GaAs semiconductor bars are well established as reliable and highly efficient laser sources. As diode laser is simple in structure, small size, longer life expectancy with the advantages of low prices, it is widely used in the industry processing, such as heat treating, welding, hardening, cladding and so on. Respectively, diode laser could make it possible to establish the practical application because of rectangular beam patterns which are suitable to make fine bead with less power. At this power level, it can have many important applications, such as surgery, welding of polymers, soldering, coatings and surface treatment of metals. But there are some applications, which require much higher power and brightness, e.g. hardening, key hole welding, cutting and metal welding. In addition, High power diode lasers in the military field also have important applications. So all developed countries have attached great importance to high-power diode laser system and its applications. This is mainly due their low performance. In this paper we will introduce the structure and the principle of the high power diode stack.

  11. Porous carbon derived via KOH activation of a hypercrosslinked porous organic polymer for efficient CO{sub 2}, CH{sub 4}, H{sub 2} adsorptions and high CO{sub 2}/N{sub 2} selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Modak, Arindam; Bhaumik, Asim, E-mail: msab@iacs.res.in

    2015-12-15

    Microporous carbon having Brunauer-Emmett-Teller (BET) surface area of 2186 m{sup 2} g{sup −1} and micropore volume of 0.85 cm{sup 3} g{sup −1} has been synthesized via KOH induced high temperature carbonization of a non-conjugated hypercrosslinked organic polymer. Owing to the templating and activation by KOH, we have succeeded in making a microporous carbon from this porous polymer and the resultant carbon material showed high uptake for CO{sub 2} (7.6 mmol g{sup −1}) and CH{sub 4} (2.4 mmol g{sup −1}) at 1 atm, 273 K together with very good selectivity for the CO{sub 2}/N{sub 2} (30.2) separation. Furthermore, low pressure (1 atm) H{sub 2} (2.6 wt%, 77 K) and water uptake (57.4 wt%, 298 K) ability of this polymer derived porous activated carbon is noteworthy. - Graphical abstract: Microporous carbon with BET surface area of 2186 m{sup 2} g{sup −1} has been synthesized via KOH activation of a porous organic polymer and it showed high uptake for CO{sub 2} (7.6 mmol g{sup −1}), CH{sub 4} (2.4 mmol g{sup −1}) and H{sub 2} (2.6 wt%) at 1 atm together with very good selectivity for CO{sub 2}. - Highlights: • Porous carbon from hypercrosslinked organic polymer. • KOH activated carbon with BET surface area 2186 m{sup 2} g{sup −1}. • High CO2 uptake (7.6 mmol g{sup −1}) and CO{sub 2}/N{sub 2} selectivity (30.2). • Porous carbon also showed high H{sub 2} (2.6 wt%) and H{sub 2}O (57.4 wt%) uptakes.

  12. Highly Efficient Spectrally Stable Red Perovskite Light-Emitting Diodes.

    Science.gov (United States)

    Tian, Yu; Zhou, Chenkun; Worku, Michael; Wang, Xi; Ling, Yichuan; Gao, Hanwei; Zhou, Yan; Miao, Yu; Guan, Jingjiao; Ma, Biwu

    2018-05-01

    Perovskite light-emitting diodes (LEDs) have recently attracted great research interest for their narrow emissions and solution processability. Remarkable progress has been achieved in green perovskite LEDs in recent years, but not blue or red ones. Here, highly efficient and spectrally stable red perovskite LEDs with quasi-2D perovskite/poly(ethylene oxide) (PEO) composite thin films as the light-emitting layer are reported. By controlling the molar ratios of organic salt (benzylammonium iodide) to inorganic salts (cesium iodide and lead iodide), luminescent quasi-2D perovskite thin films are obtained with tunable emission colors from red to deep red. The perovskite/polymer composite approach enables quasi-2D perovskite/PEO composite thin films to possess much higher photoluminescence quantum efficiencies and smoothness than their neat quasi-2D perovskite counterparts. Electrically driven LEDs with emissions peaked at 638, 664, 680, and 690 nm have been fabricated to exhibit high brightness and external quantum efficiencies (EQEs). For instance, the perovskite LED with an emission peaked at 680 nm exhibits a brightness of 1392 cd m -2 and an EQE of 6.23%. Moreover, exceptional electroluminescence spectral stability under continuous device operation has been achieved for these red perovskite LEDs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Designing high efficient solar powered lighting systems

    DEFF Research Database (Denmark)

    Poulsen, Peter Behrensdorff; Thorsteinsson, Sune; Lindén, Johannes

    2016-01-01

    Some major challenges in the development of L2L products is the lack of efficient converter electronics, modelling tools for dimensioning and furthermore, characterization facilities to support the successful development of the products. We report the development of 2 Three-Port-Converters respec...

  14. Improving the Efficiency of Organic Solar Cells upon Addition of Polyvinylpyridine

    Directory of Open Access Journals (Sweden)

    Rita Rodrigues

    2014-12-01

    Full Text Available We report on the efficiency improvement of organic solar cells (OPVs based on the low energy gap polyfluorene derivative, APFO-3, and the soluble C60 fullerene PCBM, upon addition of a residual amount of poly (4-vinylpyridine (PVP. We find that the addition of 1% by weight of PVP with respect to the APFO-3 content leads to an increase of efficiency from 2.4% to 2.9%. Modifications in the phase separation details of the active layer were investigated as a possible origin of the efficiency increase. At high concentrations of PVP, the blend morphology is radically altered as observed by Atomic Force Microscopy. Although the use of low molecular weight additives is a routine method to improve OPVs efficiency, this report shows that inert polymers, in terms of optical and charge transport properties, may also improve the performance of polymer-based solar cells.

  15. Enhanced efficiency in single-host white organic light-emitting diode by triplet exciton conversion

    International Nuclear Information System (INIS)

    Wu, Qingyang; Zhang, Shiming; Yue, Shouzhen; Zhang, Zhensong; Xie, Guohua; Zhao, Yi; Liu, Shiyong

    2013-01-01

    The authors observe that the external quantum efficiency (EQE) of the Iridium (III) bis(4-phenylthieno [3,2-c]pyridinato-N,C 2′ )acetylacetonate (PO-01) based yellow organic light-emitting diode (OLED) is significantly increased by uniformly co-doping Iridium (III)bis[(4,6-difluorophenyl)-pyridinato-N,C 2− ] (FIrpic) and PO-01 into the same wide band-gap host of N,N ′ -dicarbazolyl-3, 5-benzene (mCP). Detailed investigation indicates that the efficiency enhancement is ascribed to effective triplet exciton gathering by FIrpic, followed by energy transfer to PO-01. Compared to the control device, which has maximum EQE of 10.5%, an improved maximum EQE of 13.2% is obtained in the optimization white device based on FIrpic and PO-01 emission according to this principle. This work makes it easier for a single host white OLED to simultaneously harvest high efficiency in both blue and yellow units. Comprehensive experimental results show that this phenomenon can also be found and utilized in other popular hosts to realize more efficient white devices. -- Highlights: • This work makes easier for a single host white OLED to harvest high efficiency in both blue and yellow units. • Efficiency enhancement is ascribed to effective triplet exciton gathering by FIrpic, followed by energy transfer to PO-01. • This phenomenon can also be found and utilized in other popular hosts to realize more efficient white devices

  16. Enhanced efficiency in single-host white organic light-emitting diode by triplet exciton conversion

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qingyang, E-mail: wqy1527@163.com [State Key laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Zhang, Shiming [State Key laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Département of Chemical Engineering, École Polytechnique de Montréal, Montréal, Québec, Canada H3C3J7 (Canada); Yue, Shouzhen; Zhang, Zhensong [State Key laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Xie, Guohua [Institut für Angewandte Photophysik, Technische Universtität Dresden, Dresden 01062 (Germany); Zhao, Yi; Liu, Shiyong [State Key laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

    2013-11-15

    The authors observe that the external quantum efficiency (EQE) of the Iridium (III) bis(4-phenylthieno [3,2-c]pyridinato-N,C{sup 2′})acetylacetonate (PO-01) based yellow organic light-emitting diode (OLED) is significantly increased by uniformly co-doping Iridium (III)bis[(4,6-difluorophenyl)-pyridinato-N,C{sup 2−}] (FIrpic) and PO-01 into the same wide band-gap host of N,N{sup ′}-dicarbazolyl-3, 5-benzene (mCP). Detailed investigation indicates that the efficiency enhancement is ascribed to effective triplet exciton gathering by FIrpic, followed by energy transfer to PO-01. Compared to the control device, which has maximum EQE of 10.5%, an improved maximum EQE of 13.2% is obtained in the optimization white device based on FIrpic and PO-01 emission according to this principle. This work makes it easier for a single host white OLED to simultaneously harvest high efficiency in both blue and yellow units. Comprehensive experimental results show that this phenomenon can also be found and utilized in other popular hosts to realize more efficient white devices. -- Highlights: • This work makes easier for a single host white OLED to harvest high efficiency in both blue and yellow units. • Efficiency enhancement is ascribed to effective triplet exciton gathering by FIrpic, followed by energy transfer to PO-01. • This phenomenon can also be found and utilized in other popular hosts to realize more efficient white devices.

  17. Deep-blue efficient OLED based on NPB with little efficiency roll-off under high current density

    Science.gov (United States)

    Liu, Jian

    2017-03-01

    NPB usually is used as a hole-transport layer in OLED. In fact, it is a standard pure blue-emission material. However, its light-emitting efficiency in OLED is low due to emissive nature of organic material. Herein, a deep-blue OLDE based on NPB was fabricated. The light-emitting efficiency of the device demonstrates a moderate value, and efficiency roll-off is little under high current density. The device demonstrates that the electroplex's emission decreases with increasing electric field intensity.

  18. Energy efficiency indicators for high electric-load buildings

    Energy Technology Data Exchange (ETDEWEB)

    Aebischer, Bernard; Balmer, Markus A.; Kinney, Satkartar; Le Strat, Pascale; Shibata, Yoshiaki; Varone, Frederic

    2003-06-01

    Energy per unit of floor area is not an adequate indicator for energy efficiency in high electric-load buildings. For two activities, restaurants and computer centres, alternative indicators for energy efficiency are discussed.

  19. Efficient and Highly Aldehyde Selective Wacker Oxidation

    KAUST Repository

    Teo, Peili; Wickens, Zachary K.; Dong, Guangbin; Grubbs, Robert H.

    2012-01-01

    A method for efficient and aldehyde-selective Wacker oxidation of aryl-substituted olefins using PdCl 2(MeCN) 2, 1,4-benzoquinone, and t-BuOH in air is described. Up to a 96% yield of aldehyde can be obtained, and up to 99% selectivity can be achieved with styrene-related substrates. © 2012 American Chemical Society.

  20. Efficient and Highly Aldehyde Selective Wacker Oxidation

    KAUST Repository

    Teo, Peili

    2012-07-06

    A method for efficient and aldehyde-selective Wacker oxidation of aryl-substituted olefins using PdCl 2(MeCN) 2, 1,4-benzoquinone, and t-BuOH in air is described. Up to a 96% yield of aldehyde can be obtained, and up to 99% selectivity can be achieved with styrene-related substrates. © 2012 American Chemical Society.

  1. ROLE OF METHODS FOR CAR-REPAIRING ORGANIZATIONS AND THEIR INFLUENCE ON INCREASE OF LABOR EFFICIENCY

    Directory of Open Access Journals (Sweden)

    V. V. Myamlin

    2010-11-01

    Full Text Available The advantages of the line form of production organization are shown. The examples of forming the lines in different branches of industry are given. Main characteristics of line production are presented. An important role in the development of new structures of car repair lines promoting in production efficiency and labor productivity growth is emphasized. Huge reserves in this direction can be seen in creation of multi-subject flexible asynchronous systems with high level of production mechanization and automation.

  2. Highly Efficient and Reproducible Nonfullerene Solar Cells from Hydrocarbon Solvents

    KAUST Repository

    Wadsworth, Andrew; Ashraf, Raja; Abdelsamie, Maged; Pont, Sebastian; Little, Mark; Moser, Maximilian; Hamid, Zeinab; Neophytou, Marios; Zhang, Weimin; Amassian, Aram; Durrant, James R.; Baran, Derya; McCulloch, Iain

    2017-01-01

    With chlorinated solvents unlikely to be permitted for use in solution-processed organic solar cells in industry, there must be a focus on developing nonchlorinated solvent systems. Here we report high-efficiency devices utilizing a low-bandgap donor polymer (PffBT4T-2DT) and a nonfullerene acceptor (EH-IDTBR) from hydrocarbon solvents and without using additives. When mesitylene was used as the solvent, rather than chlorobenzene, an improved power conversion efficiency (11.1%) was achieved without the need for pre- or post-treatments. Despite altering the processing conditions to environmentally friendly solvents and room-temperature coating, grazing incident X-ray measurements confirmed that active layers processed from hydrocarbon solvents retained the robust nanomorphology obtained with hot-processed chlorinated solvents. The main advantages of hydrocarbon solvent-processed devices, besides the improved efficiencies, were the reproducibility and storage lifetime of devices. Mesitylene devices showed better reproducibility and shelf life up to 4000 h with PCE dropping by only 8% of its initial value.

  3. Highly Efficient and Reproducible Nonfullerene Solar Cells from Hydrocarbon Solvents

    KAUST Repository

    Wadsworth, Andrew

    2017-06-01

    With chlorinated solvents unlikely to be permitted for use in solution-processed organic solar cells in industry, there must be a focus on developing nonchlorinated solvent systems. Here we report high-efficiency devices utilizing a low-bandgap donor polymer (PffBT4T-2DT) and a nonfullerene acceptor (EH-IDTBR) from hydrocarbon solvents and without using additives. When mesitylene was used as the solvent, rather than chlorobenzene, an improved power conversion efficiency (11.1%) was achieved without the need for pre- or post-treatments. Despite altering the processing conditions to environmentally friendly solvents and room-temperature coating, grazing incident X-ray measurements confirmed that active layers processed from hydrocarbon solvents retained the robust nanomorphology obtained with hot-processed chlorinated solvents. The main advantages of hydrocarbon solvent-processed devices, besides the improved efficiencies, were the reproducibility and storage lifetime of devices. Mesitylene devices showed better reproducibility and shelf life up to 4000 h with PCE dropping by only 8% of its initial value.

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

    Science.gov (United States)

    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.

  5. FY 1998 report on the results of the R and D on the venture promotion type regional consortium small-/medium-size enterprise creation base type. Research and development of energy-saving and high-efficient drying system of high water content organic substances; 1998 nendo kogansui yukibutsu no shoenegata kokoritsu kanso system no kenkyu kaihatsu seika hokokusho. 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    This project is implemented to save energy for drying bio-products (biological object organic substances), such as laver, fish and shellfish, shiitake mushroom and tobacco leaves, without deteriorating their flavor, taste, color and luster. In particular, it is aimed at development of high-efficiency drying devices friendly to these products, e.g., laver, and in harmony with energy-saving environments through creation of novel drying chambers and peripheral facilities around the heat exchanger, and elucidation of the drying processes of the organic substances. These devices can of course contribute to energy saving and environmental protection, and, at the same time, bring about the merit of easily controlling the three elements of the drying conditions precisely for the process of drying a specific organic substance. Moreover, the R and D project will help establish know-hows that allow the drying devices to diffuse into various areas for specific drying environments characteristic of region and product. The FY 1998 R and D efforts include (1) elucidation of the stepwise process for drying each product, (2) development of the algorithm for thermohydraulic elucidation of the system and drying process, (3) development of drying chambers for drying systems, and designing and fabrication of the optimum chamber shapes, and (4) evaluation of the energy flows and mass balances in the drying system. (NEDO)

  6. High efficiency nebulization for helium inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Jorabchi, Kaveh; McCormick, Ryan; Levine, Jonathan A.; Liu Huiying; Nam, S.-H.; Montaser, Akbar

    2006-01-01

    A pneumatically-driven, high efficiency nebulizer is explored for helium inductively coupled plasma mass spectrometry. The aerosol characteristics and analyte transport efficiencies of the high efficiency nebulizer for nebulization with helium are measured and compared to the results obtained with argon. Analytical performance indices of the helium inductively coupled plasma mass spectrometry are evaluated in terms of detection limits and precision. The helium inductively coupled plasma mass spectrometry detection limits obtained with the high efficiency nebulizer at 200 μL/min are higher than those achieved with the ultrasonic nebulizer consuming 2 mL/min solution, however, precision is generally better with high efficiency nebulizer (1-4% vs. 3-8% with ultrasonic nebulizer). Detection limits with the high efficiency nebulizer at 200 μL/min solution uptake rate approach those using ultrasonic nebulizer upon efficient desolvation with a heated spray chamber followed by a Peltier-cooled multipass condenser

  7. Highly Efficient TADF Polymer Electroluminescence with Reduced Efficiency Roll-off via Interfacial Exciplex Host Strategy.

    Science.gov (United States)

    Lin, Xingdong; Zhu, Yunhui; Zhang, Baohua; Zhao, Xiaofei; Yao, Bing; Cheng, Yanxiang; Li, Zhanguo; Qu, Yi; Xie, Zhiyuan

    2018-01-10

    Solution-processed organic light-emitting diodes (s-OLED) consisting of TAPC/TmPyPB interfacial exciplex host and polymer PAPTC TADF emitter are prepared, simultaneously displaying ultralow voltages (2.50/2.91/3.51/4.91 V at luminance of 1/100/1000/1000 cd m -2 ), high efficiencies (14.9%, 50.1 lm W -1 ), and extremely low roll-off rates (J 50 of 63.16 mA cm -2 , L 50 of ca. 15000 cd m -2 ). Such performance is distinctly higher than that of pure-PAPTC s-OLED. Compared to pure-PAPTC, the advanced emissive layer structure of TAPC:PAPTC/TmPyPB is unique in much higher PL quantum yield (79.5 vs 36.3%) and nearly 4-fold enhancement in k RISC of the PAPTC emitter to 1.48 × 10 7 s -1 .

  8. Recent Advances in High Efficiency Solar Cells

    Institute of Scientific and Technical Information of China (English)

    Yoshio; Ohshita; Hidetoshi; Suzuki; Kenichi; Nishimura; Masafumi; Yamaguchi

    2007-01-01

    1 Results The conversion efficiency of sunlight to electricity is limited around 25%,when we use single junction solar cells. In the single junction cells,the major energy losses arise from the spectrum mismatching. When the photons excite carriers with energy well in excess of the bandgap,these excess energies were converted to heat by the rapid thermalization. On the other hand,the light with lower energy than that of the bandgap cannot be absorbed by the semiconductor,resulting in the losses. One way...

  9. High efficiency cyclotron trap assisted positron moderator

    OpenAIRE

    Gerchow, L.; Cooke, D. A.; Braccini, S.; Döbeli, M.; Kirch, K.; Köster, U.; Müller, A.; Van Der Meulen, N. P.; Vermeulen, C.; Rubbia, A.; Crivelli, P.

    2017-01-01

    We report the realisation of a cyclotron trap assisted positron tungsten moderator for the conversion of positrons with a broad keV- few MeV energy spectrum to a mono-energetic eV beam with an efficiency of 1.8(2)% defined as the ratio of the slow positrons divided by the $\\beta^+$ activity of the radioactive source. This is an improvement of almost two orders of magnitude compared to the state of the art of tungsten moderators. The simulation validated with this measurement suggests that usi...

  10. A high-efficiency electromechanical battery

    Science.gov (United States)

    Post, Richard F.; Fowler, T. K.; Post, Stephen F.

    1993-03-01

    In our society there is a growing need for efficient cost-effective means for storing electrical energy. The electric auto is a prime example. Storage systems for the electric utilities, and for wind or solar power, are other examples. While electrochemical cells could in principle supply these needs, the existing E-C batteries have well-known limitations. This article addresses an alternative, the electromechanical battery (EMB). An EMB is a modular unit consisting of an evacuated housing containing a fiber-composite rotor. The rotor is supported by magnetic bearings and contains an integrally mounted permanent magnet array. This article addresses design issues for EMBs with rotors made up of nested cylinders. Issues addressed include rotational stability, stress distributions, generator/motor power and efficiency, power conversion, and cost. It is concluded that the use of EMBs in electric autos could result in a fivefold reduction (relative to the IC engine) in the primary energy input required for urban driving, with a concomitant major positive impact on our economy and on air pollution.

  11. A Solution Processed Flexible Nanocomposite Electrode with Efficient Light Extraction for Organic Light Emitting Diodes

    Science.gov (United States)

    Li, Lu; Liang, Jiajie; Chou, Shu-Yu; Zhu, Xiaodan; Niu, Xiaofan; Zhibinyu; Pei, Qibing

    2014-03-01

    Highly efficient organic light emitting diodes (OLEDs) based on multiple layers of vapor evaporated small molecules, indium tin oxide transparent electrode, and glass substrate have been extensively investigated and are being commercialized. The light extraction from the exciton radiative decay is limited to less than 30% due to plasmonic quenching on the metallic cathode and the waveguide in the multi-layer sandwich structure. Here we report a flexible nanocomposite electrode comprising single-walled carbon nanotubes and silver nanowires stacked and embedded in the surface of a polymer substrate. Nanoparticles of barium strontium titanate are dispersed within the substrate to enhance light extraction efficiency. Green polymer OLED (PLEDs) fabricated on the nanocomposite electrode exhibit a maximum current efficiency of 118 cd/A at 10,000 cd/m2 with the calculated external quantum efficiency being 38.9%. The efficiencies of white PLEDs are 46.7 cd/A and 30.5%, respectively. The devices can be bent to 3 mm radius repeatedly without significant loss of electroluminescent performance. The nanocomposite electrode could pave the way to high-efficiency flexible OLEDs with simplified device structure and low fabrication cost.

  12. Large-area high-efficiency flexible PHOLED lighting panels

    Science.gov (United States)

    Pang, Huiqing; Mandlik, Prashant; Levermore, Peter A.; Silvernail, Jeff; Ma, Ruiqing; Brown, Julie J.

    2012-09-01

    Organic Light Emitting Diodes (OLEDs) provide various attractive features for next generation illumination systems, including high efficiency, low power, thin and flexible form factor. In this work, we incorporated phosphorescent emitters and demonstrated highly efficient white phosphorescent OLED (PHOLED) devices on flexible plastic substrates. The 0.94 cm2 small-area device has total thickness of approximately 0.25 mm and achieved 63 lm/W at 1,000 cd/m2 with CRI = 85 and CCT = 2920 K. We further designed and fabricated a 15 cm x 15 cm large-area flexible white OLED lighting panels, finished with a hybrid single-layer ultra-low permeability single layer barrier (SLB) encapsulation film. The flexible panel has an active area of 116.4 cm2, and achieved a power efficacy of 47 lm/W at 1,000 cd/m2 with CRI = 83 and CCT = 3470 K. The efficacy of the panel at 3,000 cd/m2 is 43 lm/W. The large-area flexible PHOLED lighting panel is to bring out enormous possibilities to the future general lighting applications.

  13. Development of high efficiency neutron detectors

    International Nuclear Information System (INIS)

    Pickrell, M.M.; Menlove, H.O.

    1993-01-01

    The authors have designed a novel neutron detector system using conventional 3 He detector tubes and composites of polyethylene and graphite. At this time the design consists entirely of MCNP simulations of different detector configurations and materials. These detectors are applicable to low-level passive and active neutron assay systems such as the passive add-a-source and the 252 Cf shuffler. Monte Carlo simulations of these neutron detector designs achieved efficiencies of over 35% for assay chambers that can accommodate 55-gal. drums. Only slight increases in the number of detector tubes and helium pressure are required. The detectors also have reduced die-away times. Potential applications are coincident and multiplicity neutron counting for waste disposal and safeguards. The authors will present the general design philosophy, underlying physics, calculation mechanics, and results

  14. High-Efficient Circuits for Ternary Addition

    Directory of Open Access Journals (Sweden)

    Reza Faghih Mirzaee

    2014-01-01

    Full Text Available New ternary adders, which are fundamental components of ternary addition, are presented in this paper. They are on the basis of a logic style which mostly generates binary signals. Therefore, static power dissipation reaches its minimum extent. Extensive different analyses are carried out to examine how efficient the new designs are. For instance, the ternary ripple adder constructed by the proposed ternary half and full adders consumes 2.33 μW less power than the one implemented by the previous adder cells. It is almost twice faster as well. Due to their unique superior characteristics for ternary circuitry, carbon nanotube field-effect transistors are used to form the novel circuits, which are entirely suitable for practical applications.

  15. A high-efficiency superconductor distributed amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Herr, Q P, E-mail: quentin.herr@ngc.co [Northrop Grumman Corporation, 7323 Aviation Boulevard, Baltimore, MD 21240 (United States)

    2010-02-15

    A superconductor output amplifier that converts single-flux-quantum signals to a non-return-to-zero pattern is reported using a twelve-stage distributed amplifier configuration. The output amplitude is measured to be 1.75 mV over a wide bias current range of {+-} 12%. The bit error rate is measured using a Delta-Sigma data pattern to be less than 1 x 10{sup -9} at 10 Gb s{sup -1} per channel. Analysis of the eye diagram suggests that the actual bit error rate may be much lower. The amplifier has power efficiency of 12% neglecting the termination resistor, which may be eliminated from the circuit with a small modification. (rapid communication)

  16. High efficiency solid-state sensitized heterojunction photovoltaic device

    KAUST Repository

    Wang, Mingkui

    2010-06-01

    The high molar extinction coefficient heteroleptic ruthenium dye, NaRu(4,4′-bis(5-(hexylthio)thiophen-2-yl)-2,2′-bipyridine) (4-carboxylic acid-4′-carboxylate-2,2′-bipyridine) (NCS) 2, exhibits certified 5% electric power conversion efficiency at AM 1.5 solar irradiation (100 mW cm-2) in a solid-state dye-sensitized solar cell using 2,2′,7,7′-tetrakis-(N,N-di-pmethoxyphenylamine)-9, 9′-spirobifluorene (spiro-MeOTAD) as the organic hole-transporting material. This demonstration elucidates a class of photovoltaic devices with potential for low-cost power generation. © 2010 Elsevier Ltd. All rights reserved.

  17. High efficiency solid-state sensitized heterojunction photovoltaic device

    KAUST Repository

    Wang, Mingkui; Liu, Jingyuan; Cevey-Ha, Ngoc-Le; Moon, Soo-Jin; Liska, Paul; Humphry-Baker, Robin; Moser, Jacques-E.; Grä tzel, Carole; Wang, Peng; Zakeeruddin, Shaik M.

    2010-01-01

    The high molar extinction coefficient heteroleptic ruthenium dye, NaRu(4,4′-bis(5-(hexylthio)thiophen-2-yl)-2,2′-bipyridine) (4-carboxylic acid-4′-carboxylate-2,2′-bipyridine) (NCS) 2, exhibits certified 5% electric power conversion efficiency at AM 1.5 solar irradiation (100 mW cm-2) in a solid-state dye-sensitized solar cell using 2,2′,7,7′-tetrakis-(N,N-di-pmethoxyphenylamine)-9, 9′-spirobifluorene (spiro-MeOTAD) as the organic hole-transporting material. This demonstration elucidates a class of photovoltaic devices with potential for low-cost power generation. © 2010 Elsevier Ltd. All rights reserved.

  18. Analysis of the external and internal quantum efficiency of multi-emitter, white organic light emitting diodes

    Science.gov (United States)

    Furno, Mauro; Rosenow, Thomas C.; Gather, Malte C.; Lüssem, Björn; Leo, Karl

    2012-10-01

    We report on a theoretical framework for the efficiency analysis of complex, multi-emitter organic light emitting diodes (OLEDs). The calculation approach makes use of electromagnetic modeling to quantify the overall OLED photon outcoupling efficiency and a phenomenological description for electrical and excitonic processes. From the comparison of optical modeling results and measurements of the total external quantum efficiency, we obtain reliable estimates of internal quantum yield. As application of the model, we analyze high-efficiency stacked white OLEDs and comment on the various efficiency loss channels present in the devices.

  19. Phosphorescent cyclometalated complexes for efficient blue organic light-emitting diodes

    Science.gov (United States)

    Suzuri, Yoshiyuki; Oshiyama, Tomohiro; Ito, Hiroto; Hiyama, Kunihisa; Kita, Hiroshi

    2014-10-01

    Phosphorescent emitters are extremely important for efficient organic light-emitting diodes (OLEDs), which attract significant attention. Phosphorescent emitters, which have a high phosphorescence quantum yield at room temperature, typically contain a heavy metal such as iridium and have been reported to emit blue, green and red light. In particular, the blue cyclometalated complexes with high efficiency and high stability are being developed. In this review, we focus on blue cyclometalated complexes. Recent progress of computational analysis necessary to design a cyclometalated complex is introduced. The prediction of the radiative transition is indispensable to get an emissive cyclometalated complex. We summarize four methods to control phosphorescence peak of the cyclometalated complex: (i) substituent effect on ligands, (ii) effects of ancillary ligands on heteroleptic complexes, (iii) design of the ligand skeleton, and (iv) selection of the central metal. It is considered that novel ligand skeletons would be important to achieve both a high efficiency and long lifetime in the blue OLEDs. Moreover, the combination of an emitter and a host is important as well as the emitter itself. According to the dependences on the combination of an emitter and a host, the control of exciton density of the triplet is necessary to achieve both a high efficiency and a long lifetime, because the annihilations of the triplet state cause exciton quenching and material deterioration.

  20. High Efficiency Regenerative Helium Compressor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Helium plays several critical rolls in spacecraft propulsion. High pressure helium is commonly used to pressurize propellant fuel tanks. Helium cryocoolers can be...

  1. Highly Efficient, Durable Regenerative Solid Oxide Stack, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Precision Combustion, Inc. (PCI) proposes to develop a highly efficient regenerative solid oxide stack design. Novel structural elements allow direct internal...

  2. Early evolution of efficient enzymes and genome organization

    Directory of Open Access Journals (Sweden)

    Szilágyi András

    2012-10-01

    Full Text Available Abstract Background Cellular life with complex metabolism probably evolved during the reign of RNA, when it served as both information carrier and enzyme. Jensen proposed that enzymes of primordial cells possessed broad specificities: they were generalist. When and under what conditions could primordial metabolism run by generalist enzymes evolve to contemporary-type metabolism run by specific enzymes? Results Here we show by numerical simulation of an enzyme-catalyzed reaction chain that specialist enzymes spread after the invention of the chromosome because protocells harbouring unlinked genes maintain largely non-specific enzymes to reduce their assortment load. When genes are linked on chromosomes, high enzyme specificity evolves because it increases biomass production, also by reducing taxation by side reactions. Conclusion The constitution of the genetic system has a profound influence on the limits of metabolic efficiency. The major evolutionary transition to chromosomes is thus proven to be a prerequisite for a complex metabolism. Furthermore, the appearance of specific enzymes opens the door for the evolution of their regulation. Reviewers This article was reviewed by Sándor Pongor, Gáspár Jékely, and Rob Knight.

  3. Mixing of phosphorescent and exciplex emission in efficient organic electroluminescent devices.

    Science.gov (United States)

    Cherpak, Vladyslav; Stakhira, Pavlo; Minaev, Boris; Baryshnikov, Gleb; Stromylo, Evgeniy; Helzhynskyy, Igor; Chapran, Marian; Volyniuk, Dmytro; Hotra, Zenon; Dabuliene, Asta; Tomkeviciene, Ausra; Voznyak, Lesya; Grazulevicius, Juozas Vidas

    2015-01-21

    We fabricated a yellow organic light-emitting diode (OLED) based on the star-shaped donor compound tri(9-hexylcarbazol-3-yl)amine, which provides formation of the interface exciplexes with the iridium(III) bis[4,6-difluorophenyl]-pyridinato-N,C2']picolinate (FIrpic). The exciplex emission is characterized by a broad band and provides a condition to realize the highly effective white OLED. It consists of a combination of the blue phosphorescent emission from the FIrpic complex and a broad efficient delayed fluorescence induced by thermal activation with additional direct phosphorescence from the triplet exciplex formed at the interface. The fabricated exciplex-type device exhibits a high brightness of 38 000 cd/m(2) and a high external quantum efficiency.

  4. Efficient organic tandem solar cells based on small molecules

    Energy Technology Data Exchange (ETDEWEB)

    Riede, Moritz; Widmer, Johannes; Timmreck, Ronny; Wynands, David; Leo, Karl [Institut fuer Angewandte Photophysik, Technische Universitaet Dresden, George-Baehr-Str. 1, 01069 Dresden (Germany); Uhrich, Christian; Schwartz, Gregor; Gnehr, Wolf-Michael; Hildebrandt, Dirk; Weiss, Andre; Pfeiffer, Martin [Heliatek GmbH, Treidlerstr. 3, 01139 Dresden (Germany); Hwang, Jaehyung; Sundarraj, Sudhakar; Erk, Peter [BASF SE, GVC/E-J542, 67056 Ludwigshafen (Germany)

    2011-08-23

    In this paper, two vacuum processed single heterojunction organic solar cells with complementary absorption are described and the construction and optimization of tandem solar cells based on the combination of these heterojunctions demonstrated. The red-absorbing heterojunction consists of C{sub 60} and a fluorinated zinc phthalocyanine derivative (F4-ZnPc) that leads to a 0.1-0.15 V higher open circuit voltage V{sub oc} than the commonly used ZnPc. The second heterojunction incorporates C{sub 60} and a dicyanovinyl-capped sexithiophene derivative (DCV6T) that mainly absorbs in the green. The combination of both heterojunctions into one tandem solar cell leads to an absorption over the whole visible range of the sun spectrum. Thickness variations of the transparent p-doped optical spacer between both subcells in the tandem solar cell is shown to lead to a significant change in short circuit current density j{sub sc} due to optical interference effects, whereas V{sub oc} and fill factor are hardly affected. The maximum efficiency {eta} of about 5.6% is found for a spacer thickness of 150-165 nm. Based on the optimized 165nm thick spacer, effects of intensity and angle of illumination, and temperature on a tandem device are investigated. Variations in illumination intensity lead to a linear change in j{sub sc} over three orders of magnitude and a nearly constant {eta} in the range of 30 to 310 mW cm{sup -2}. Despite the stacked heterojunctions, the performance of the tandem device is robust against different illumination angles: j{sub sc} and {eta} closely follow a cosine behavior between 0 and 70 . Investigations of the temperature behavior of the tandem device show an increase in {eta} of 0.016 percentage points per Kelvin between -20 C and 25 C followed by a plateau up to 50 C. Finally, further optimization of the tandem stack results in a certified {eta} of (6.07 {+-} 0.24)% on (1.9893 {+-} 0.0060)cm{sup 2} (Fraunhofer ISE), i.e., areas large enough to be of

  5. Educational Management Organizations as High Reliability Organizations: A Study of Victory's Philadelphia High School Reform Work

    Science.gov (United States)

    Thomas, David E.

    2013-01-01

    This executive position paper proposes recommendations for designing reform models between public and private sectors dedicated to improving school reform work in low performing urban high schools. It reviews scholarly research about for-profit educational management organizations, high reliability organizations, American high school reform, and…

  6. The role of polymer dots on efficiency enhancement of organic solar cells: Improving charge transport property

    Science.gov (United States)

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

    2017-07-01

    In this work, poly(9,9-dioctylfluorene)-co-(4,7-di-2-thienyl-2,1,3-benzothiadiazole) (PF-5DTBT) and copolymer poly(styrene-co-maleic anhydride) (PSMA) dots were prepared as additive for active layer doping to enhance the power conversion efficiency (PCE) of organic solar cells (OSCs), which based on poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4‧,7‧-di-2-thienyl-2‧,1‧,3‧-benzothiadiazole) (PCDTBT) and [6,6]-phenyl C71 butyric acid methyl-ester (PC71BM). A high efficiency of 7.40% was achieved due to increase of short-circuit current (Jsc) and fill factor (FF). The operation mechanism of OSCs doping with polymer dots was investigated, which demonstrated that the efficiency enhancement ascribes to improvement of electrical properties, such as exciton generation, exction dissociation, charge transport, and charge collection.

  7. High-efficiency airfoil rudders applied to submarines

    Directory of Open Access Journals (Sweden)

    ZHOU Yimei

    2017-03-01

    Full Text Available Modern submarine design puts forward higher and higher requirements for control surfaces, and this creates a requirement for designers to constantly innovate new types of rudder so as to improve the efficiency of control surfaces. Adopting the high-efficiency airfoil rudder is one of the most effective measures for improving the efficiency of control surfaces. In this paper, we put forward an optimization method for a high-efficiency airfoil rudder on the basis of a comparative analysis of the various strengths and weaknesses of the airfoil, and the numerical calculation method is adopted to analyze the influence rule of the hydrodynamic characteristics and wake field by using the high-efficiency airfoil rudder and the conventional NACA rudder comparatively; at the same time, a model load test in a towing tank was carried out, and the test results and simulation calculation obtained good consistency:the error between them was less than 10%. The experimental results show that the steerage of a high-efficiency airfoil rudder is increased by more than 40% when compared with the conventional rudder, but the total resistance is close:the error is no more than 4%. Adopting a high-efficiency airfoil rudder brings much greater lifting efficiency than the total resistance of the boat. The results show that high-efficiency airfoil rudder has obvious advantages for improving the efficiency of control, giving it good application prospects.

  8. Tris(2-(1 H -pyrazol-1-yl)pyridine)cobalt(III) as p-Type Dopant for Organic Semiconductors and Its Application in Highly Efficient Solid-State Dye-Sensitized Solar Cells

    KAUST Repository

    Burschka, Julian; Dualeh, Amalie; Kessler, Florian; Baranoff, Etienne; Cevey-Ha, Ngoc-Lê ; Yi, Chenyi; Nazeeruddin, Mohammad K.; Grä tzel, Michael

    2011-01-01

    Chemical doping is an important strategy to alter the charge-transport properties of both molecular and polymeric organic semiconductors that find widespread application in organic electronic devices. We report on the use of a new class of Co

  9. Efficient white organic light emitting devices with dual emitting layers

    International Nuclear Information System (INIS)

    Wu Yaoshan; Hwang Shiaowen; Chen Hsianhung; Lee Mengting; Shen Wenjian; Chen, C.H.

    2005-01-01

    In this paper, a new white organic light-emitting device (OLED) with the structure of indium tin oxide / CF x / 1,4-bis[N-(1-naphthyl)-N'-phenylamino]-biphenyl (NPB) (30 nm)/NPB: 2,8-di(t-butyl)-5,11-di[4-(t-butyl)phenyl]-6,12-diphenylnaphthacene (20 nm; 1.6 %) / 2-methyl-9,10-di(2-naphthyl) anthracene: p-bis(p-N,N-di-phenyl-aminostyryl)benzene (40 nm, 3%) / aluminum tris(8-hydroxyquinoline) (20 nm) / LiF (1 nm) / Al (200 nm) has been investigated. The device showed white emission with a high-luminous yield of 9.75 cd/A at 20 mA/cm 2 , but its Commission Internationale de l'Eclairage chromaticity coordinates appeared to change from (0.34, 0.42) at 6 mA/cm2 to (0.27, 0.37) at 200 mA/cm 2 due to the shift of recombination zone. The change of color with drive current was suppressed by introduction of an electron-blocking layer of NPB along with a hole-blocking layer of aluminum (III) bis(2-methyl-8-quinolinato)4-phenylphenolato to the white OLED which successfully confined the recombination site and achieved a luminous yield of 9.9 cd/A at 20 mA/cm 2

  10. Efficient white organic light emitting devices with dual emitting layers

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yaoshan [Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan, 30050 (China); Hwang Shiaowen [Display Institute, Microelectronics and Information Systems Research Center, National Chiao Tung University, Hsinchu, Taiwan, 30050 (China)]. E-mail: jesse@faculty.nctu.edu.tw; Chen Hsianhung [Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan, 30050 (China); Lee Mengting [Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan, 30050 (China); Shen Wenjian [Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan, 30050 (China); Chen, C.H. [Display Institute, Microelectronics and Information Systems Research Center, National Chiao Tung University, Hsinchu, Taiwan, 30050 (China)

    2005-09-22

    In this paper, a new white organic light-emitting device (OLED) with the structure of indium tin oxide / CF {sub x} / 1,4-bis[N-(1-naphthyl)-N'-phenylamino]-biphenyl (NPB) (30 nm)/NPB: 2,8-di(t-butyl)-5,11-di[4-(t-butyl)phenyl]-6,12-diphenylnaphthacene (20 nm; 1.6 %) / 2-methyl-9,10-di(2-naphthyl) anthracene: p-bis(p-N,N-di-phenyl-aminostyryl)benzene (40 nm, 3%) / aluminum tris(8-hydroxyquinoline) (20 nm) / LiF (1 nm) / Al (200 nm) has been investigated. The device showed white emission with a high-luminous yield of 9.75 cd/A at 20 mA/cm{sup 2}, but its Commission Internationale de l'Eclairage chromaticity coordinates appeared to change from (0.34, 0.42) at 6 mA/cm2 to (0.27, 0.37) at 200 mA/cm{sup 2} due to the shift of recombination zone. The change of color with drive current was suppressed by introduction of an electron-blocking layer of NPB along with a hole-blocking layer of aluminum (III) bis(2-methyl-8-quinolinato)4-phenylphenolato to the white OLED which successfully confined the recombination site and achieved a luminous yield of 9.9 cd/A at 20 mA/cm{sup 2}.

  11. Extremely efficient flexible organic light-emitting diodes with modified graphene anode

    Science.gov (United States)

    Han, Tae-Hee; Lee, Youngbin; Choi, Mi-Ri; Woo, Seong-Hoon; Bae, Sang-Hoon; Hong, Byung Hee; Ahn, Jong-Hyun; Lee, Tae-Woo

    2012-02-01

    Although graphene films have a strong potential to replace indium tin oxide anodes in organic light-emitting diodes (OLEDs), to date, the luminous efficiency of OLEDs with graphene anodes has been limited by a lack of efficient methods to improve the low work function and reduce the sheet resistance of graphene films to the levels required for electrodes. Here, we fabricate flexible OLEDs by modifying the graphene anode to have a high work function and low sheet resistance, and thus achieve extremely high luminous efficiencies (37.2 lm W-1 in fluorescent OLEDs, 102.7 lm W-1 in phosphorescent OLEDs), which are significantly higher than those of optimized devices with an indium tin oxide anode (24.1 lm W-1 in fluorescent OLEDs, 85.6 lm W-1 in phosphorescent OLEDs). We also fabricate flexible white OLED lighting devices using the graphene anode. These results demonstrate the great potential of graphene anodes for use in a wide variety of high-performance flexible organic optoelectronics.

  12. High Efficiency, High Density Terrestrial Panel. [for solar cell modules

    Science.gov (United States)

    Wohlgemuth, J.; Wihl, M.; Rosenfield, T.

    1979-01-01

    Terrestrial panels were fabricated using rectangular cells. Packing densities in excess of 90% with panel conversion efficiencies greater than 13% were obtained. Higher density panels can be produced on a cost competitive basis with the standard salami panels.

  13. 40 CFR 761.71 - High efficiency boilers.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false High efficiency boilers. 761.71... PROHIBITIONS Storage and Disposal § 761.71 High efficiency boilers. (a) To burn mineral oil dielectric fluid containing a PCB concentration of ≥50 ppm, but boiler shall comply with the following...

  14. One-dimensional organic lead halide perovskites with efficient bluish white-light emission

    Science.gov (United States)

    Yuan, Zhao; Zhou, Chenkun; Tian, Yu; Shu, Yu; Messier, Joshua; Wang, Jamie C.; van de Burgt, Lambertus J.; Kountouriotis, Konstantinos; Xin, Yan; Holt, Ethan; Schanze, Kirk; Clark, Ronald; Siegrist, Theo; Ma, Biwu

    2017-01-01

    Organic-inorganic hybrid metal halide perovskites, an emerging class of solution processable photoactive materials, welcome a new member with a one-dimensional structure. Herein we report the synthesis, crystal structure and photophysical properties of one-dimensional organic lead bromide perovskites, C4N2H14PbBr4, in which the edge sharing octahedral lead bromide chains [PbBr4 2-]∞ are surrounded by the organic cations C4N2H14 2+ to form the bulk assembly of core-shell quantum wires. This unique one-dimensional structure enables strong quantum confinement with the formation of self-trapped excited states that give efficient bluish white-light emissions with photoluminescence quantum efficiencies of approximately 20% for the bulk single crystals and 12% for the microscale crystals. This work verifies once again that one-dimensional systems are favourable for exciton self-trapping to produce highly efficient below-gap broadband luminescence, and opens up a new route towards superior light emitters based on bulk quantum materials.

  15. HIGH EFFICIENCY DESULFURIZATION OF SYNTHESIS GAS

    Energy Technology Data Exchange (ETDEWEB)

    Anirban Mukherjee; Kwang-Bok Yi; Elizabeth J. Podlaha; Douglas P. Harrison

    2001-11-01

    Mixed metal oxides containing CeO{sub 2} and ZrO{sub 2} are being studied as high temperature desulfurization sorbents capable of achieving the DOE Vision 21 target of 1 ppmv of less H{sub 2}S. The research is justified by recent results in this laboratory that showed that reduced CeO{sub 2}, designated CeO{sub n} (1.5 < n < 2.0), is capable of achieving the 1 ppmv target in highly reducing gas atmospheres. The addition of ZrO{sub 2} has improved the performance of oxidation catalysts and three-way automotive catalysts containing CeO{sub 2}, and should have similar beneficial effects on CeO{sub 2} desulfurization sorbents. An electrochemical method for synthesizing CeO{sub 2}-ZrO{sub 2} has been developed and the products have been characterized by XRD and TEM during year 01. Nanocrystalline particles having a diameter of about 5 nm and containing from approximately 10 mol% to 80 mol% ZrO{sub 2} have been prepared. XRD showed the product to be a solid solution at low ZrO{sub 2} contents with a separate ZrO{sub 2} phase emerging at higher ZrO{sub 2} levels. Phase separation did not occur when the solid solutions were heat treated at 700 C. A flow reactor system constructed of quartz and teflon has been constructed, and a gas chromatograph equipped with a pulsed flame photometric detector (PFPD) suitable for measuring sub-ppmv levels of H{sub 2}S has been purchased with LSU matching funds. Preliminary desulfurization tests using commercial CeO{sub 2} and CeO{sub 2}-ZrO{sub 2} in highly reducing gas compositions has confirmed that CeO{sub 2}-ZrO{sub 2} is more effective than CeO{sub 2} in removing H{sub 2}S. At 700 C the product H{sub 2}S concentration using CeO{sub 2}-ZrO{sub 2} sorbent was near the 0.1 ppmv PFPD detection limit during the prebreakthrough period.

  16. Highly efficient induction of chirality in intramolecular

    Science.gov (United States)

    Cossio; Arrieta; Lecea; Alajarin; Vidal; Tovar

    2000-06-16

    Highly stereocontrolled, intramolecular [2 + 2] cycloadditions between ketenimines and imines leading to 1,2-dihydroazeto[2, 1-b]quinazolines have been achieved. The source of stereocontrol is a chiral carbon atom adjacent either to the iminic carbon or nitrogen atom. In the first case, the stereocontrol stems from the preference for the axial conformer in the first transition structure. In the second case, the origin of the stereocontrol lies on the two-electron stabilizing interaction between the C-C bond being formed and the sigma orbital corresponding to the polar C-X bond, X being an electronegative atom. These models can be extended to other related systems for predicting the stereochemical outcome in this intramolecular reaction.

  17. High Efficiency, Low Cost Scintillators for PET

    International Nuclear Information System (INIS)

    Kanai Shah

    2007-01-01

    Inorganic scintillation detectors coupled to PMTs are an important element of medical imaging applications such as positron emission tomography (PET). Performance as well as cost of these systems is limited by the properties of the scintillation detectors available at present. The Phase I project was aimed at demonstrating the feasibility of producing high performance scintillators using a low cost fabrication approach. Samples of these scintillators were produced and their performance was evaluated. Overall, the Phase I effort was very successful. The Phase II project will be aimed at advancing the new scintillation technology for PET. Large samples of the new scintillators will be produced and their performance will be evaluated. PET modules based on the new scintillators will also be built and characterized

  18. Compact and highly efficient laser pump cavity

    Science.gov (United States)

    Chang, Jim J.; Bass, Isaac L.; Zapata, Luis E.

    1999-01-01

    A new, compact, side-pumped laser pump cavity design which uses non-conventional optics for injection of laser-diode light into a laser pump chamber includes a plurality of elongated light concentration channels. In one embodiment, the light concentration channels are compound parabolic concentrators (CPC) which have very small exit apertures so that light will not escape from the pumping chamber and will be multiply reflected through the laser rod. This new design effectively traps the pump radiation inside the pump chamber that encloses the laser rod. It enables more uniform laser pumping and highly effective recycle of pump radiation, leading to significantly improved laser performance. This new design also effectively widens the acceptable radiation wavelength of the diodes, resulting in a more reliable laser performance with lower cost.

  19. Fused Methoxynaphthyl Phenanthrimidazole Semiconductors as Functional Layer in High Efficient OLEDs.

    Science.gov (United States)

    Jayabharathi, Jayaraman; Ramanathan, Periyasamy; Karunakaran, Chockalingam; Thanikachalam, Venugopal

    2016-01-01

    Efficient hole transport materials based on novel fused methoxynaphthyl phenanthrimidazole core structure were synthesised and characterized. Their device performances in phosphorescent organic light emitting diodes were investigated. The high thermal stability in combination with the reversible oxidation process made promising candidates as hole-transporting materials for organic light-emitting devices. Highly efficient Alq3-based organic light emitting devices have been developed using phenanthrimidazoles as functional layers between NPB [4,4-bis(N-(1-naphthyl)-N-phenylamino)biphenyl] and Alq3 [tris(8-hydroxyquinoline)aluminium] layers. Using the device of ITO/NPB/4/Alq3/LiF/Al, a maximum luminous efficiency of 5.99 cd A(-1) was obtained with a maximum brightness of 40,623 cd m(-2) and a power efficiency of 5.25 lm W(-1).

  20. Zirconium-based highly porous metal-organic framework (MOF-545) as an efficient adsorbent for vortex assisted-solid phase extraction of lead from cereal, beverage and water samples.

    Science.gov (United States)

    Tokalıoğlu, Şerife; Yavuz, Emre; Demir, Selçuk; Patat, Şaban

    2017-12-15

    In this study, zirconium-based highly porous metal-organic framework, MOF-545, was synthesized and characterized. The surface area of MOF-545 was found to be 2192m 2 /g. This adsorbent was used for the first time as an adsorbent for the vortex assisted-solid phase extraction of Pb(II) from cereal, beverage and water samples. Lead in solutions was determined by FAAS. The optimal experimental conditions were as follows: the amount of MOF-545, 10mg; pH of sample, 7; adsorption and elution time, 15min; and elution solvent, 2mL of 1molL -1 HCl. Under the optimal conditions of the method, the limit of detection, preconcentration factor and precision as RSD% were found to be 1.78μgL -1 , 125 and 2.6%, respectively. The adsorption capacity of the adsorbent for lead was found to be 73mgg -1 . The method was successfully verified by analyzing two certified reference materials (BCR-482 Lichen and SPS-WW1 Batch 114) and spiked chickpea, bean, wheat, lentil, cherry juice, mineral water, well water and wastewater samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. HIGH EFFICIENCY DESULFURIZATION OF SYNTHESIS GAS

    Energy Technology Data Exchange (ETDEWEB)

    Kwang-Bok Yi; Anirban Mukherjee; Elizabeth J. Podlaha; Douglas P. Harrison

    2004-03-01

    Mixed metal oxides containing ceria and zirconia have been studied as high temperature desulfurization sorbents with the objective of achieving the DOE Vision 21 target of 1 ppmv or less H{sub 2}S in the product gas. The research was justified by recent results in this laboratory that showed that reduced CeO{sub 2}, designated CeOn (1.5 < n < 2.0), is capable of achieving the 1 ppmv target in highly reducing gas atmospheres. The addition of ZrO{sub 2} has improved the performance of oxidation catalysts and three-way automotive catalysts containing CeO{sub 2}, and was postulated to have similar beneficial effects on CeO{sub 2} desulfurization sorbents. An electrochemical method for synthesizing CeO{sub 2}-ZrO{sub 2} mixtures was developed and the products were characterized by XRD and TEM during year 01. Nanocrystalline particles having a diameter of about 5 nm and containing from approximately 10 mol% to 80 mol% ZrO{sub 2} were prepared. XRD analysis showed the product to be a solid solution at low ZrO{sub 2} contents with a separate ZrO{sub 2} phase emerging at higher ZrO{sub 2} levels. Unfortunately, the quantity of CeO{sub 2}-ZrO{sub 2} that could be prepared electrochemically was too small to permit desulfurization testing. Also during year 01 a laboratory-scale fixed-bed reactor was constructed for desulfurization testing. All components of the reactor and analytical systems that were exposed to low concentrations of H{sub 2}S were constructed of quartz, Teflon, or silcosteel. Reactor product gas composition as a function of time was determined using a Varian 3800 gas chromatograph equipped with a pulsed flame photometric detector (PFPD) for measuring low H{sub 2}S concentrations from approximately 0.1 to 10 ppmv, and a thermal conductivity detector (TCD) for higher concentrations of H{sub 2}S. Larger quantities of CeO{sub 2}-ZrO{sub 2} mixtures from other sources, including mixtures prepared in this laboratory using a coprecipitation procedure, were obtained

  2. High-performance vertical organic transistors.

    Science.gov (United States)

    Kleemann, Hans; Günther, Alrun A; Leo, Karl; Lüssem, Björn

    2013-11-11

    Vertical organic thin-film transistors (VOTFTs) are promising devices to overcome the transconductance and cut-off frequency restrictions of horizontal organic thin-film transistors. The basic physical mechanisms of VOTFT operation, however, are not well understood and VOTFTs often require complex patterning techniques using self-assembly processes which impedes a future large-area production. In this contribution, high-performance vertical organic transistors comprising pentacene for p-type operation and C60 for n-type operation are presented. The static current-voltage behavior as well as the fundamental scaling laws of such transistors are studied, disclosing a remarkable transistor operation with a behavior limited by injection of charge carriers. The transistors are manufactured by photolithography, in contrast to other VOTFT concepts using self-assembled source electrodes. Fluorinated photoresist and solvent compounds allow for photolithographical patterning directly and strongly onto the organic materials, simplifying the fabrication protocol and making VOTFTs a prospective candidate for future high-performance applications of organic transistors. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Aerosol Mass Scattering Efficiency: Generalized Treatment of the Organic Fraction

    Science.gov (United States)

    Garland, R. M.; Ravishankara, A. R.; Lovejoy, E. R.; Tolbert, M. A.; Baynard, T.

    2005-12-01

    Atmospheric aerosols are complex mixtures of organic and inorganic compounds. Current efforts to provide a simplified parameterization to describe the RH dependence of water uptake and associated optical properties lack the capability to include any dependence on the composition of the organic fraction. Using laboratory generated aerosol we have investigated the validity of such simplified treatment of organic fraction and estimated potential biases. In this study, we use cavity ring-down aerosol extinction photometry (CRD-AEP) to study the relative humidity (RH) dependence of the light extinction of aerosols, σep, simultaneously considering the influence of particle size, chemical composition, and mixing state (internal and external mixtures). We have produced internally mixed aerosol systems including; ammonium sulfate, ammonium nitrate, sodium chloride, dicarboxylic acids, sugars, amino acids and humic acid. These aerosols are produced with an atomizer and size-selected with a Differential Mobility Analyzer (DMA). The particles then enter into a CRD-AEP to measure dry extinction, σep(Dry), after which they travel into a RH conditioner and another CRD-AEP to measure the humidified aerosol extinction, fσ(ep)RH. The ratio of the humidified extinction to the dry extinction is fσ(ep)RH. Representative organic compounds were found to have fσ(ep)RH values that are much smaller than pure salts; though the fσ(ep)RH values vary little within the organic compounds studied. In addition, we have found that treating the inorganic/organic aerosols as external mixtures is generally correct to within ~10%, indicating appropriate simplified treatment of the RH dependence of atmospheric aerosol according to inorganic/organic fraction. In this presentation, we include recommendations for the generalized treatment of the organic fraction, exceptions to this generalized behavior, and estimates of the potential bias caused by generalized treatment.

  4. Efficient light emission from inorganic and organic semiconductor hybrid structures by energy-level tuning

    Science.gov (United States)

    Schlesinger, R.; Bianchi, F.; Blumstengel, S.; Christodoulou, C.; Ovsyannikov, R.; Kobin, B.; Moudgil, K.; Barlow, S.; Hecht, S.; Marder, S.R.; Henneberger, F.; Koch, N.

    2015-01-01

    The fundamental limits of inorganic semiconductors for light emitting applications, such as holographic displays, biomedical imaging and ultrafast data processing and communication, might be overcome by hybridization with their organic counterparts, which feature enhanced frequency response and colour range. Innovative hybrid inorganic/organic structures exploit efficient electrical injection and high excitation density of inorganic semiconductors and subsequent energy transfer to the organic semiconductor, provided that the radiative emission yield is high. An inherent obstacle to that end is the unfavourable energy level offset at hybrid inorganic/organic structures, which rather facilitates charge transfer that quenches light emission. Here, we introduce a technologically relevant method to optimize the hybrid structure's energy levels, here comprising ZnO and a tailored ladder-type oligophenylene. The ZnO work function is substantially lowered with an organometallic donor monolayer, aligning the frontier levels of the inorganic and organic semiconductors. This increases the hybrid structure's radiative emission yield sevenfold, validating the relevance of our approach. PMID:25872919

  5. Efficient light emission from inorganic and organic semiconductor hybrid structures by energy-level tuning.

    Science.gov (United States)

    Schlesinger, R; Bianchi, F; Blumstengel, S; Christodoulou, C; Ovsyannikov, R; Kobin, B; Moudgil, K; Barlow, S; Hecht, S; Marder, S R; Henneberger, F; Koch, N

    2015-04-15

    The fundamental limits of inorganic semiconductors for light emitting applications, such as holographic displays, biomedical imaging and ultrafast data processing and communication, might be overcome by hybridization with their organic counterparts, which feature enhanced frequency response and colour range. Innovative hybrid inorganic/organic structures exploit efficient electrical injection and high excitation density of inorganic semiconductors and subsequent energy transfer to the organic semiconductor, provided that the radiative emission yield is high. An inherent obstacle to that end is the unfavourable energy level offset at hybrid inorganic/organic structures, which rather facilitates charge transfer that quenches light emission. Here, we introduce a technologically relevant method to optimize the hybrid structure's energy levels, here comprising ZnO and a tailored ladder-type oligophenylene. The ZnO work function is substantially lowered with an organometallic donor monolayer, aligning the frontier levels of the inorganic and organic semiconductors. This increases the hybrid structure's radiative emission yield sevenfold, validating the relevance of our approach.

  6. All passive architecture for high efficiency cascaded Raman conversion

    Science.gov (United States)

    Balaswamy, V.; Arun, S.; Chayran, G.; Supradeepa, V. R.

    2018-02-01

    Cascaded Raman fiber lasers have offered a convenient method to obtain scalable, high-power sources at various wavelength regions inaccessible with rare-earth doped fiber lasers. A limitation previously was the reduced efficiency of these lasers. Recently, new architectures have been proposed to enhance efficiency, but this came at the cost of enhanced complexity, requiring an additional low-power, cascaded Raman laser. In this work, we overcome this with a new, all-passive architecture for high-efficiency cascaded Raman conversion. We demonstrate our architecture with a fifth-order cascaded Raman converter from 1117nm to 1480nm with output power of ~64W and efficiency of 60%.

  7. A High-Current, Stable Nonaqueous Organic Redox Flow Battery

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Xiaoliang; Duan, Wentao; Huang, Jinhua; Zhang, Lu; Li, Bin; Reed, David; Xu, Wu; Sprenkle, Vincent; Wang, Wei

    2016-10-14

    Nonaqueous redox flow batteries are promising in pursuit of high-energy storage systems owing to the broad voltage window, but currently are facing key challenges such as poor cycling stability and lack of suitable membranes. Here we report a new nonaqueous all-organic flow chemistry that demonstrates an outstanding cell cycling stability primarily because of high chemical persistency of the organic radical redox species and their good compatibility with the supporting electrolyte. A feasibility study shows that Daramic® and Celgard® porous separators can lead to high cell conductivity in flow cells thus producing remarkable cell efficiency and material utilization even at high current operations. This result suggests that the thickness and pore size are the key performance-determining factors for porous separators. With the greatly improved flow cell performance, this new flow system largely addresses the above mentioned challenges and the findings may greatly expedite the development of durable nonaqueous flow batteries.

  8. Modifying the organic/electrode interface in Organic Solar Cells (OSCs) and improving the efficiency of solution-processed phosphorescent Organic Light-Emitting Diodes (OLEDs)

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Teng [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    Organic semiconductors devices, such as, organic solar cells (OSCs), organic light-emitting diodes (OLEDs) and organic field-effect transistors (OFETs) have drawn increasing interest in recent decades. As organic materials are flexible, light weight, and potentially low-cost, organic semiconductor devices are considered to be an alternative to their inorganic counterparts. This dissertation will focus mainly on OSCs and OLEDs. As a clean and renewable energy source, the development of OSCs is very promising. Cells with 9.2% power conversion efficiency (PCE) were reported this year, compared to < 8% two years ago. OSCs belong to the so-called third generation solar cells and are still under development. While OLEDs are a more mature and better studied field, with commercial products already launched in the market, there are still several key issues: (1) the cost of OSCs/OLEDs is still high, largely due to the costly manufacturing processes; (2) the efficiency of OSCs/OLEDs needs to be improved; (3) the lifetime of OSCs/OLEDs is not sufficient compared to their inorganic counterparts; (4) the physics models of the behavior of the devices are not satisfactory. All these limitations invoke the demand for new organic materials, improved device architectures, low-cost fabrication methods, and better understanding of device physics. For OSCs, we attempted to improve the PCE by modifying the interlayer between active layer/metal. We found that ethylene glycol (EG) treated poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (PEDOT: PSS) improves hole collection at the metal/polymer interface, furthermore it also affects the growth of the poly(3- hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) blends, making the phase segregation more favorable for charge collection. We then studied organic/inorganic tandem cells. We also investigated the effect of a thin LiF layer on the hole-collection of copper phthalocyanine (CuPc)/C70-based small molecular OSCs. A

  9. Molecular Entropy, Thermal Efficiency, and Designing of Working Fluids for Organic Rankine Cycles

    Science.gov (United States)

    Wang, Jingtao; Zhang, Jin; Chen, Zhiyou

    2012-06-01

    A shortage of fossil energy sources boosts the utilization of renewable energy. Among numerous novel techniques, recovering energy from low-grade heat sources through power generation via organic Rankine cycles (ORCs) is one of the focuses. Properties of working fluids are crucial for the ORC's performance. Many studies have been done to select proper working fluids or to design new working fluids. However, no researcher has systematically investigated the relationship between molecular structures and thermal efficiencies of various working fluids for an ideal ORC. This paper has investigated the interrelations of molecular structures, molecular entropies, and thermal efficiencies of various working fluids for an ideal ORC. By calculating thermal efficiencies and molecular entropies, we find that the molecular entropy is the most appropriate thermophysical property of a working fluid to determine how much energy can be converted into work and how much cannot in a system. Generally speaking, working fluids with low entropies will generally have high thermal efficiency for an ideal ORC. Based on this understanding, the direct interrelations of molecular structures and entropies provide an explicit interrelation between molecular structures and thermal efficiencies, and thus provide an insightful direction for molecular design of novel working fluids for ORCs.

  10. Efficiency of indigenous ground phosphate rocks, organic fertilizer ...

    African Journals Online (AJOL)

    The lowest Relative Agronomic Efficiency (RAE) values estimated for the test fertilizer materials in the 1st cropping were 81.5 and 117.5% in soils A and B, respectively. The respective values for 2nd cropping were 78.3 and 62.0%. It was clear that the indigenous GRP, OF and their mixtures have great potentials as ...

  11. Perovskite Solar Cells for High-Efficiency Tandems

    Energy Technology Data Exchange (ETDEWEB)

    McGehee, Michael [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Buonassisi, Tonio [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2017-09-30

    The first monolithic perovskite/silicon tandem was made with a diffused silicon p-n junction, a tunnel junction made of n++ hydrogenated amorphous silicon, a titania electron transport layer, a methylammonium lead iodide absorber, and a Spiro-OMeTAD hole transport layer (HTL). The power conversion efficiency (PCE) was only 13.7% due to excessive parasitic absorption of light in the HTL, limiting the matched current density to 11.5 mA/cm2. Werner et al.15 raised the PCE to a record 21.2% by switching to a silicon heterojunction bottom cell and carefully tuning layer thicknesses to achieve lower optical loss and a higher current density of 15.9 mA/cm2. It is clear from these reports that minimizing parasitic absorption in the window layers is crucial to achieving higher current densities and efficiencies in monolithic tandems. To this end, the window layers through which light first passes before entering the perovskite and silicon absorber materials must be highly transparent. The front electrode must also be conductive to carry current laterally across the top of the device. Indium tin oxide (ITO) is widely utilized as a transparent electrode in optoelectronic devices such as flat-panel displays, smart windows, organic light-emitting diodes, and solar cells due to its high conductivity and broadband transparency. ITO is typically deposited through magnetron sputtering; however, the high kinetic energy of sputtered particles can damage underlying layers. In perovskite solar cells, a sputter buffer layer is required to protect the perovskite and organic carrier extraction layers from damage during sputter deposition. The ideal buffer layer should also be energetically well aligned so as to act as a carrier-selective contact, have a wide bandgap to enable high optical transmission, and have no reaction with the halides in the perovskite. Additionally, this buffer layer should act as a diffusion barrier layer to prevent both

  12. Stabilization void-fill encapsulation high-efficiency particulate filters

    International Nuclear Information System (INIS)

    Alexander, R.G.; Stewart, W.E.; Phillips, S.J.; Serkowski, M.M.; England, J.L.; Boynton, H.C.

    1994-05-01

    This report discusses high-efficiency particulate air (HEPA) filter systems that which are contaminated with radionuclides are part of the nuclear fuel processing systems conducted by the US Department of Energy (DOE) and require replacement and safe and efficient disposal for plant safety. Two K-3 HEPA filters were removed from service, placed burial boxes, buried, and safely and efficiently stabilized remotely which reduced radiation exposure to personnel and the environment

  13. Design of High Efficiency Illumination for LED Lighting

    OpenAIRE

    Chang, Yong-Nong; Cheng, Hung-Liang; Kuo, Chih-Ming

    2013-01-01

    A high efficiency illumination for LED street lighting is proposed. For energy saving, this paper uses Class-E resonant inverter as main electric circuit to improve efficiency. In addition, single dimming control has the best efficiency, simplest control scheme and lowest circuit cost among other types of dimming techniques. Multiple serial-connected transformers used to drive the LED strings as they can provide galvanic isolation and have the advantage of good current distribution against de...

  14. Flexible organic solar cells including efficiency enhancing grating structures

    DEFF Research Database (Denmark)

    Oliveira Hansen, Roana Melina de; Liu, Yinghui; Madsen, Morten

    2013-01-01

    , such as photolithography and electron-beam lithography, besides the steps required for the bulk-heterojunction organic solar cell fabrication. After the production steps, the solar cells on polyimide are peeled off the silicon support substrates, resulting in flexible devices containing nanostructures for light absorption......In this work, a new method for the fabrication of organic solar cells containing functional light-trapping nanostructures on flexible substrates is presented. Polyimide is spin-coated on silicon support substrates, enabling standard micro- and nanotechnology fabrication techniques...

  15. The productive efficiency of organic farming: the case of grape sector in Catalonia

    Energy Technology Data Exchange (ETDEWEB)

    Guesmi, B.; Serra, T.; Kallas, Z.; Gil Roig, J. M.

    2012-11-01

    Knowledge about productivity and efficiency differences between conventional and organic farms has important implications for the evaluation of the economic viability of these two agricultural practices. The main purpose of this study was to compare the efficiency ratings of organic and conventional grape farms in Catalonia. To do so, we fit a stochastic production frontier to cross sectional, farm-level data collected from a sample of 141 Catalan farms that specialize in grape growing. Results show that organic farmers, on average, are more efficient than their conventional counterparts (efficiency ratings are on the order of 0.80 and 0.64, respectively). Apart from adoption of organic practices, experience is also found to improve technical efficiency. Conversely, technical efficiency tends to decrease with the relevance of unpaid family labor, farm location in less favored areas, and farmers strong environmental preservation preferences. (Author) 41 refs.

  16. Efficient hole injection in organic light-emitting diodes using polyvinylidenefluoride as an interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Soon Ok; Soo Yook, Kyoung [Department of Polymer Science and Engineering, Dankook University, Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi 448-701 (Korea, Republic of); Lee, Jun Yeob, E-mail: leej17@dankook.ac.k [Department of Polymer Science and Engineering, Dankook University, Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi 448-701 (Korea, Republic of)

    2010-10-15

    The effect of the polyvinylidenefluoride (PVDF) interlayer on the hole injection and the device performances of the green phosphorescent organic light-emitting diodes (PHOLEDs) was investigated. The hole current density of the hole only device was improved and the power efficiency of the green PHOLEDs was enhanced from 10.5 to 12.5 lm/W by the PVDF interlayer. The reduction of the interfacial energy barrier was responsible for the high hole current density in the PVDF interlayer based green PHOLEDs.

  17. A Nonfullerene Small Molecule Acceptor with 3D Interlocking Geometry Enabling Efficient Organic Solar Cells.

    Science.gov (United States)

    Lee, Jaewon; Singh, Ranbir; Sin, Dong Hun; Kim, Heung Gyu; Song, Kyu Chan; Cho, Kilwon

    2016-01-06

    A new 3D nonfullerene small-molecule acceptor is reported. The 3D interlocking geometry of the small-molecule acceptor enables uniform molecular conformation and strong intermolecular connectivity, facilitating favorable nanoscale phase separation and electron charge transfer. By employing both a novel polymer donor and a nonfullerene small-molecule acceptor in the solution-processed organic solar cells, a high-power conversion efficiency of close to 6% is demonstrated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Morphology control and device optimization for efficient organic solar cells

    NARCIS (Netherlands)

    Gevaerts, Veronique

    2013-01-01

    Renewable energy is paramount for a sustainable global future. Solar cells convert solar light directly into electricity and are therefore of great interest in meeting the world’s energy demand. Currently crystalline silicon solar cells dominate the market. Solution processed organic solar cells can

  19. High performance organic ultraviolet photodetectors based on m-MTDATA

    Science.gov (United States)

    Zhao, Zhongli; Bai, Xiaofeng; Shang, Yubin; Yang, Jikai; Li, Baozeng; Song, De

    2018-02-01

    We demonstrate highly efficient organic ultraviolet photodetectors using 4,4',4'' -tris[3-methyl-pheny(phenyl) amino] triphenylamine (m-MTDATA) and aluminum Tris(8-Hydroxyquinolinate) Synonym Alq3). The optimized photodetector delivers a photocurrent of 1.40 mA/cm2 at10 V, corresponding to a response of 127 mA/W under an illumination of 375 nm UV light irradiation with an intensity of 10.5 mW/cm2 and a detectivity of 2.15×1011 cm Hz1/2 /W. The high response is attributed to the larger band offset at m-MTDATA/ Alq3 heterojunction, the suppression of radiative decay of m-MTDATA and efficient electron transfer from m-MTDATA to Alq3. The working mechanism of harvesting high performance is also discussed in detail.

  20. The Energy Efficiency of High Intensity Proton Driver Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Yakovlev, Vyacheslav [Fermilab; Grillenberger, Joachim [PSI, Villigen; Kim, Sang-Ho [ORNL, Oak Ridge (main); Seidel, Mike [PSI, Villigen; Yoshii, Masahito [JAEA, Ibaraki

    2017-05-01

    For MW class proton driver accelerators the energy efficiency is an important aspect; the talk reviews the efficiency of different accelerator concepts including s.c./n.c. linac, rapid cycling synchrotron, cyclotron; the potential of these concepts for very high beam power is discussed.

  1. An Efficient, “Burn in” Free Organic Solar Cell Employing a Nonfullerene Electron Acceptor

    KAUST Repository

    Cha, Hyojung

    2017-06-28

    A comparison of the efficiency, stability, and photophysics of organic solar cells employing poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3\\'″-di(2-octyldodecyl)-2,2\\';5\\',2″;5″,2\\'″-quaterthiophen-5,5\\'″-diyl)] (PffBT4T-2OD) as a donor polymer blended with either the nonfullerene acceptor EH-IDTBR or the fullerene derivative, [6,6]-phenyl C71 butyric acid methyl ester (PC71 BM) as electron acceptors is reported. Inverted PffBT4T-2OD:EH-IDTBR blend solar cell fabricated without any processing additive achieves power conversion efficiencies (PCEs) of 9.5 ± 0.2%. The devices exhibit a high open circuit voltage of 1.08 ± 0.01 V, attributed to the high lowest unoccupied molecular orbital (LUMO) level of EH-IDTBR. Photoluminescence quenching and transient absorption data are employed to elucidate the ultrafast kinetics and efficiencies of charge separation in both blends, with PffBT4T-2OD exciton diffusion kinetics within polymer domains, and geminate recombination losses following exciton separation being identified as key factors determining the efficiency of photocurrent generation. Remarkably, while encapsulated PffBT4T-2OD:PC71 BM solar cells show significant efficiency loss under simulated solar irradiation (“burn in” degradation) due to the trap-assisted recombination through increased photoinduced trap states, PffBT4T-2OD:EH-IDTBR solar cell shows negligible burn in efficiency loss. Furthermore, PffBT4T-2OD:EH-IDTBR solar cells are found to be substantially more stable under 85 °C thermal stress than PffBT4T-2OD:PC71BM devices.

  2. An Efficient, "Burn in" Free Organic Solar Cell Employing a Nonfullerene Electron Acceptor.

    Science.gov (United States)

    Cha, Hyojung; Wu, Jiaying; Wadsworth, Andrew; Nagitta, Jade; Limbu, Saurav; Pont, Sebastian; Li, Zhe; Searle, Justin; Wyatt, Mark F; Baran, Derya; Kim, Ji-Seon; McCulloch, Iain; Durrant, James R

    2017-09-01

    A comparison of the efficiency, stability, and photophysics of organic solar cells employing poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3'″-di(2-octyldodecyl)-2,2';5',2″;5″,2'″-quaterthiophen-5,5'″-diyl)] (PffBT4T-2OD) as a donor polymer blended with either the nonfullerene acceptor EH-IDTBR or the fullerene derivative, [6,6]-phenyl C 71 butyric acid methyl ester (PC 71 BM) as electron acceptors is reported. Inverted PffBT4T-2OD:EH-IDTBR blend solar cell fabricated without any processing additive achieves power conversion efficiencies (PCEs) of 9.5 ± 0.2%. The devices exhibit a high open circuit voltage of 1.08 ± 0.01 V, attributed to the high lowest unoccupied molecular orbital (LUMO) level of EH-IDTBR. Photoluminescence quenching and transient absorption data are employed to elucidate the ultrafast kinetics and efficiencies of charge separation in both blends, with PffBT4T-2OD exciton diffusion kinetics within polymer domains, and geminate recombination losses following exciton separation being identified as key factors determining the efficiency of photocurrent generation. Remarkably, while encapsulated PffBT4T-2OD:PC 71 BM solar cells show significant efficiency loss under simulated solar irradiation ("burn in" degradation) due to the trap-assisted recombination through increased photoinduced trap states, PffBT4T-2OD:EH-IDTBR solar cell shows negligible burn in efficiency loss. Furthermore, PffBT4T-2OD:EH-IDTBR solar cells are found to be substantially more stable under 85 °C thermal stress than PffBT4T-2OD:PC 71 BM devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. High-Performance Vertical Organic Electrochemical Transistors.

    Science.gov (United States)

    Donahue, Mary J; Williamson, Adam; Strakosas, Xenofon; Friedlein, Jacob T; McLeod, Robert R; Gleskova, Helena; Malliaras, George G

    2018-02-01

    Organic electrochemical transistors (OECTs) are promising transducers for biointerfacing due to their high transconductance, biocompatibility, and availability in a variety of form factors. Most OECTs reported to date, however, utilize rather large channels, limiting the transistor performance and resulting in a low transistor density. This is typically a consequence of limitations associated with traditional fabrication methods and with 2D substrates. Here, the fabrication and characterization of OECTs with vertically stacked contacts, which overcome these limitations, is reported. The resulting vertical transistors exhibit a reduced footprint, increased intrinsic transconductance of up to 57 mS, and a geometry-normalized transconductance of 814 S m -1 . The fabrication process is straightforward and compatible with sensitive organic materials, and allows exceptional control over the transistor channel length. This novel 3D fabrication method is particularly suited for applications where high density is needed, such as in implantable devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Improved power efficiency of blue fluorescent organic light-emitting diode with intermixed host structure

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Shouzhen; Zhang, Shiming; Zhang, Zhensong; Wu, Yukun; Wang, Peng; Guo, Runda; Chen, Yu; Qu, Dalong; Wu, Qingyang; Zhao, Yi, E-mail: yizhao@jlu.edu.cn; Liu, Shiyong

    2013-11-15

    High power efficiency (PE) p-bis(p-N,N-diphenyl-aminostyryl)benzene (DSA-ph) based fluorescent blue organic light-emitting diode (OLED) is demonstrated by utilizing intermixed host (IH) structure. The PE outperforms those devices based on single host (SH), mixed host (MH), and double emitting layers (DELs). By further optimizing the intermixed layer, peak PE of the IH device is increased up to 8.7 lm/W (1.7 times higher than conventional SH device), which is the highest value among the DSA-ph based blue device reported so far. -- Highlights: • DSA-ph based blue fluorescent OLEDs are fabricated. • The intermixed host structure is first introduced into the blue devices. • Blue device with the highest power efficiency based on DSA-ph is obtained.

  5. Optimization of emission color and efficiency of organic light emitting diodes for lighting applications

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, Stefan; Krause, Ralf [Department of Materials Science VI, University of Erlangen-Nuernberg (Germany); Siemens AG, CT MM 1, Erlangen (Germany); Kozlowski, Fryderyk; Schmid, Guenter; Hunze, Arvid [Siemens AG, CT MM 1, Erlangen (Germany); Winnacker, Albrecht [Department of Materials Science VI, University of Erlangen-Nuernberg (Germany)

    2008-07-01

    In recent years the performance of organic light emitting diodes (OLEDs) has reached a level where OLED lighting presents an interesting application target. Research activities therefore focus amongst other things on the development of high efficient and stable white light emitting devices. We demonstrate how the color coordinates can be adjusted to achieve a warm white emission spectrum, whereas the OLED stack contains phosphorescent red and green dyes combined with a fluorescent blue one. Detailed results are presented with respect to a variation of layer thicknesses and dopant concentrations of the emission layers. Furthermore the influence of various dye molecules and hence different energy level alignments between host and dopants on color and efficiency will be discussed.

  6. Blue emitting organic semiconductors under high pressure

    DEFF Research Database (Denmark)

    Knaapila, Matti; Guha, Suchismita

    2016-01-01

    This review describes essential optical and emerging structural experiments that use high GPa range hydrostatic pressure to probe physical phenomena in blue-emitting organic semiconductors including π-conjugated polyfluorene and related compounds. The work emphasizes molecular structure and inter......This review describes essential optical and emerging structural experiments that use high GPa range hydrostatic pressure to probe physical phenomena in blue-emitting organic semiconductors including π-conjugated polyfluorene and related compounds. The work emphasizes molecular structure...... and intermolecular self-organization that typically determine transport and optical emission in π-conjugated oligomers and polymers. In this context, hydrostatic pressure through diamond anvil cells has proven to be an elegant tool to control structure and interactions without chemical intervention. This has been...... and intermolecular interactions on optical excitations, electron–phonon interaction, and changes in backbone conformations. This picture is connected to the optical high pressure studies of other π-conjugated systems and emerging x-ray scattering experiments from polyfluorenes which provides a structure-property map...

  7. An efficient link prediction index for complex military organization

    Science.gov (United States)

    Fan, Changjun; Liu, Zhong; Lu, Xin; Xiu, Baoxin; Chen, Qing

    2017-03-01

    Quality of information is crucial for decision-makers to judge the battlefield situations and design the best operation plans, however, real intelligence data are often incomplete and noisy, where missing links prediction methods and spurious links identification algorithms can be applied, if modeling the complex military organization as the complex network where nodes represent functional units and edges denote communication links. Traditional link prediction methods usually work well on homogeneous networks, but few for the heterogeneous ones. And the military network is a typical heterogeneous network, where there are different types of nodes and edges. In this paper, we proposed a combined link prediction index considering both the nodes' types effects and nodes' structural similarities, and demonstrated that it is remarkably superior to all the 25 existing similarity-based methods both in predicting missing links and identifying spurious links in a real military network data; we also investigated the algorithms' robustness under noisy environment, and found the mistaken information is more misleading than incomplete information in military areas, which is different from that in recommendation systems, and our method maintained the best performance under the condition of small noise. Since the real military network intelligence must be carefully checked at first due to its significance, and link prediction methods are just adopted to purify the network with the left latent noise, the method proposed here is applicable in real situations. In the end, as the FINC-E model, here used to describe the complex military organizations, is also suitable to many other social organizations, such as criminal networks, business organizations, etc., thus our method has its prospects in these areas for many tasks, like detecting the underground relationships between terrorists, predicting the potential business markets for decision-makers, and so on.

  8. An Organic D-π-A Dye for Record Efficiency Solid-State Sensitized Heterojunction Solar Cells

    KAUST Repository

    Cai, Ning

    2011-04-13

    The high molar absorption coefficient organic D-π-A dye C220 exhibits more than 6% certified electric power conversion efficiency at AM 1.5G solar irradiation (100 mW cm-2) in a solid-state dye-sensitized solar cell using 2,2′,7,7′-tetrakis(N,N-dimethoxyphenylamine)-9,9′- spirobifluorene (spiro-MeOTAD) as the organic hole-transporting material. This contributes to a new record (6.08% by NREL) for this type of sensitized heterojunction photovoltaic device. Efficient charge generation is proved by incident photon-to-current conversion efficiency spectra. Transient photovoltage and photocurrent decay measurements showed that the enhanced performance achieved with C220 partially stems from the high charge collection efficiency over a wide potential range. © 2011 American Chemical Society.

  9. High Efficiency Lighting with Integrated Adaptive Control (HELIAC), Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed project is the continued development of the High Efficiency Lighting with Integrated Adaptive Control (HELIAC) system. Solar radiation is not a viable...

  10. High Efficiency Lighting with Integrated Adaptive Control (HELIAC), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation of the proposed project is the development of High Efficiency Lighting with Integrated Adaptive Control (HELIAC) systems to drive plant growth. Solar...

  11. Efficiency of poly-generating high temperature fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Margalef, Pere; Brown, Tim; Brouwer, Jacob; Samuelsen, Scott [National Fuel Cell Research Center (NFCRC), University of California, Irvine, CA 92697-3550 (United States)

    2011-02-15

    High temperature fuel cells can be designed and operated to poly-generate electricity, heat, and useful chemicals (e.g., hydrogen) in a variety of configurations. The highly integrated and synergistic nature of poly-generating high temperature fuel cells, however, precludes a simple definition of efficiency for analysis and comparison of performance to traditional methods. There is a need to develop and define a methodology to calculate each of the co-product efficiencies that is useful for comparative analyses. Methodologies for calculating poly-generation efficiencies are defined and discussed. The methodologies are applied to analysis of a Hydrogen Energy Station (H{sub 2}ES) showing that high conversion efficiency can be achieved for poly-generation of electricity and hydrogen. (author)

  12. An Improved, Highly Efficient Method for the Synthesis of Bisphenols

    Directory of Open Access Journals (Sweden)

    L. S. Patil

    2011-01-01

    Full Text Available An efficient synthesis of bisphenols is described by condensation of substituted phenols with corresponding cyclic ketones in presence of cetyltrimethylammonium chloride and 3-mercaptopropionic acid as a catalyst in extremely high purity and yields.

  13. High Efficiency S-Band 20 Watt Amplifier

    Data.gov (United States)

    National Aeronautics and Space Administration — This project includes the design and build of a prototype 20 W, high efficiency, S-Band amplifier.   The design will incorporate the latest semiconductor technology,...

  14. Simple solution-processed CuOX as anode buffer layer for efficient organic solar cells

    International Nuclear Information System (INIS)

    Shen, Wenfei; Yang, Chunpeng; Bao, Xichang; Sun, Liang; Wang, Ning; Tang, Jianguo; Chen, Weichao; Yang, Renqiang

    2015-01-01

    Graphical abstract: - Highlights: • Simple solution-processed CuO X hole transport layer for efficient organic solar cell. • Good photovoltaic performances as hole transport layer in OSCs with P3HT and PBDTTT-C as donor materials. • The device with CuO X as hole transport layer shows great improved stability compared with that of device with PEDOT:PSS as hole transport layer. - Abstract: A simple, solution-processed ultrathin CuO X anode buffer layer was fabricated for high performance organic solar cells (OSCs). XPS measurement demonstrated that the CuO X was the composite of CuO and Cu 2 O. The CuO X modified ITO glass exhibit a better surface contact with the active layer. The photovoltaic performance of the devices with CuO X layer was optimized by varying the thickness of CuO X films through changing solution concentration. With P3HT:PC 61 BM as the active layer, we demonstrated an enhanced PCE of 4.14% with CuO X anode buffer layer, compared with that of PEDOT:PSS layer. The CuO X layer also exhibits efficient photovoltaic performance in devices with PBDTTT-C:PC 71 BM as the active layer. The long-term stability of CuO X device is better than that of PEDOT:PSS device. The results indicate that the easy solution-processed CuO X film can act as an efficient anode buffer layer for high-efficiency OSCs

  15. The Rise of Oxygen in the Earth's Atmosphere Controlled by the Efficient Subduction of Organic Carbon

    Science.gov (United States)

    Duncan, M. S.; Dasgupta, R.

    2017-12-01

    Carbon cycling between the Earth's surface environment, i.e., the ocean-atmosphere system, and the Earth's interior is critical for differentiation, redox evolution, and long-term habitability of the planet. This carbon cycle is influenced heavily by the extent of carbon subduction. While the fate of carbonates during subduction has been discussed in numerous studies [e.g., 1], little is known how organic carbon is quantitatively transferred from the Earth's surface to the interior. Efficient subduction of organic carbon would remove reduced carbon from the surface environment over the long-term (≥100s Myrs) while release at subduction zone arc volcanoes would result in degassing of CO2. Here we conducted high pressure-temperature experiments to determine the carbon carrying capacity of slab derived, rhyolitic melts under graphite-saturated conditions over a range of P (1.5-3.0 GPa) and T (1100-1400 °C) at a fixed melt H2O content (2 wt.%) [2]. Based on our experimental data, we developed a thermodynamic model of CO2 dissolution in C-saturated slab melts, that allows us to quantify the extent of organic carbon mobility as a function of slab P, T, and fO2 during subduction through time. Our experimental data and thermodynamic model suggest that the subduction of graphitized organic C, and graphite/diamond formed by reduction of carbonates with depth [e.g., 3], remained efficient even in ancient, hotter subduction zones - conditions at which subduction of carbonates likely remained limited [1]. Considering the efficiency the subduction of organic C and potential conditions for ancient subduction, we suggest that the lack of remobilization in subduction zones and deep sequestration of organic C in the mantle facilitated the rise and maintenance atmospheric oxygen in the Paleoproterozoic and is causally linked to the Great Oxidation Event (GOE). Our modeling shows that episodic subduction and organic C sequestration pre-GOE may also explain occasional whiffs of

  16. Process development for high-efficiency silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Gee, J.M.; Basore, P.A.; Buck, M.E.; Ruby, D.S.; Schubert, W.K.; Silva, B.L.; Tingley, J.W.

    1991-12-31

    Fabrication of high-efficiency silicon solar cells in an industrial environment requires a different optimization than in a laboratory environment. Strategies are presented for process development of high-efficiency silicon solar cells, with a goal of simplifying technology transfer into an industrial setting. The strategies emphasize the use of statistical experimental design for process optimization, and the use of baseline processes and cells for process monitoring and quality control. 8 refs.

  17. Highly efficient procedure for the transesterification of vegetable oil

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Xuezheng; Gao, Shan; He, Mingyuan [Shanghai Key Laboratory of Green Chemistry and Chemical Process, Department of Chemistry, East China Normal University, Shanghai 200062 (China); Yang, Jianguo [Shanghai Key Laboratory of Green Chemistry and Chemical Process, Department of Chemistry, East China Normal University, Shanghai 200062 (China); Energy Institute, Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

    2009-10-15

    The highly efficient procedure has been developed for the synthesis of biodiesel from vegetable oil and methanol. The KF/MgO has been selected as the most efficient catalyst for the reactions with the yield of 99.3%. Operational simplicity, without need of the purification of raw vegetable oil, low cost of the catalyst used, high activities, no saponification and reusability are the key features of this methodology. (author)

  18. The photonic nanowire: A highly efficient single-photon source

    DEFF Research Database (Denmark)

    Gregersen, Niels

    2014-01-01

    The photonic nanowire represents an attractive platform for a quantum light emitter. However, careful optical engineering using the modal method, which elegantly allows access to all relevant physical parameters, is crucial to ensure high efficiency.......The photonic nanowire represents an attractive platform for a quantum light emitter. However, careful optical engineering using the modal method, which elegantly allows access to all relevant physical parameters, is crucial to ensure high efficiency....

  19. Highly Efficient Spontaneous Emission from Self-Assembled Quantum Dots

    DEFF Research Database (Denmark)

    Johansen, Jeppe; Lund-Hansen, Toke; Hvam, Jørn Märcher

    2006-01-01

    We present time resolved measurements of spontaneous emission (SE) from InAs/GaAs quantum dots (QDs). The measurements are interpreted using Fermi's Golden Rule and from this analysis we establish the parameters for high quantum efficiency.......We present time resolved measurements of spontaneous emission (SE) from InAs/GaAs quantum dots (QDs). The measurements are interpreted using Fermi's Golden Rule and from this analysis we establish the parameters for high quantum efficiency....

  20. Global climate change: Mitigation opportunities high efficiency large chiller technology

    Energy Technology Data Exchange (ETDEWEB)

    Stanga, M.V.

    1997-12-31

    This paper, comprised of presentation viewgraphs, examines the impact of high efficiency large chiller technology on world electricity consumption and carbon dioxide emissions. Background data are summarized, and sample calculations are presented. Calculations show that presently available high energy efficiency chiller technology has the ability to substantially reduce energy consumption from large chillers. If this technology is widely implemented on a global basis, it could reduce carbon dioxide emissions by 65 million tons by 2010.

  1. High efficiency USC power plant - present status and future potential

    Energy Technology Data Exchange (ETDEWEB)

    Blum, R. [Faelleskemikerne I/S Fynsvaerket (Denmark); Hald, J. [Elsam/Elkraft/TU Denmark (Denmark)

    1998-12-31

    Increasing demand for energy production with low impact on the environment and minimised fuel consumption can be met with high efficient coal fired power plants with advanced steam parameters. An important key to this improvement is the development of high temperature materials with optimised mechanical strength. Based on the results of more than ten years of development a coal fired power plant with an efficiency above 50 % can now be realised. Future developments focus on materials which enable an efficiency of 52-55 %. (orig.) 25 refs.

  2. High efficiency USC power plant - present status and future potential

    Energy Technology Data Exchange (ETDEWEB)

    Blum, R [Faelleskemikerne I/S Fynsvaerket (Denmark); Hald, J [Elsam/Elkraft/TU Denmark (Denmark)

    1999-12-31

    Increasing demand for energy production with low impact on the environment and minimised fuel consumption can be met with high efficient coal fired power plants with advanced steam parameters. An important key to this improvement is the development of high temperature materials with optimised mechanical strength. Based on the results of more than ten years of development a coal fired power plant with an efficiency above 50 % can now be realised. Future developments focus on materials which enable an efficiency of 52-55 %. (orig.) 25 refs.

  3. Efficient Exciton Diffusion and Resonance-Energy Transfer in Multi-Layered Organic Epitaxial Nanofibers

    DEFF Research Database (Denmark)

    Tavares, Luciana; Cadelano, Michele; Quochi, Francesco

    2015-01-01

    Multi-layered epitaxial nanofibers are exemplary model systems for the study of exciton dynamics and lasing in organic materials due to their well-defined morphology, high luminescence efficiencies, and color tunability. We resort to temperature-dependent cw and picosecond photoluminescence (PL......) spectroscopy to quantify exciton diffusion and resonance-energy transfer (RET) processes in multi-layered nanofibers consisting of alternating layers of para-hexaphenyl (p6P) and α-sexithiophene (6T), serving as exciton donor and acceptor material, respectively. The high probability for RET processes...... is confirmed by Quantum Chemical calculations. The activation energy for exciton diffusion in p6P is determined to be as low as 19 meV, proving p6P epitaxial layers also as a very suitable donor material system. The small activation energy for exciton diffusion of the p6P donor material, the inferred high p6P...

  4. High efficient ZnO nanowalnuts photocatalyst: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Feng [College of Chemistry and Chemical Engineering, Mudanjiang Normal University, Mudanjiang 157011 (China); College of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025 (China); Zhang, Siwen; Liu, Yang [College of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025 (China); Liu, Hongfeng [School of Basic Medical Sciences, Mudanjiang Medical University, Mudanjiang 157011 (China); Qu, Fengyu [College of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025 (China); Cai, Xue, E-mail: xuecai@mail.sdu.edu.cn [College of Chemistry and Chemical Engineering, Mudanjiang Normal University, Mudanjiang 157011 (China); Wu, Xiang, E-mail: wuxiang@hrbnu.edu.cn [College of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025 (China)

    2014-11-15

    Highlights: • Walnut-like ZnO nanostructures are synthesized through a facile hydrothermal method. • Morphologies and microstructures of the as-obtained ZnO products were investigated. • The photocatalytic results demonstrate that methyl orange (MO) aqueous solution can be degraded over 97% after 45 min under UV light irradiation. - Abstract: Walnut-like ZnO nanostructures are successfully synthesized through a facile hydrothermal method. The structure and morphology of the as-synthesized products were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The photocatalytic properties of ZnO nanowalnuts are investigated by photodegradating several organic dyes, such as Congo red (CR), methyl orange (MO) and eosin red aqueous solutions under UV irradiation, respectively. The results demonstrate that methyl orange (MO) aqueous solution can be degraded over 97% after 45 min under UV light irradiation. In addition, eosin red and Congo red (CR) aqueous solution degradation experiments are also conducted in the same condition, respectively. It showed that ZnO nanowalnuts represent high photocatalytic activities with a degradation efficiency of 87% for CR with 115 min of irradiation and 97% for eosin red with 55 min of irradiation. The reported ZnO products may be promising candidates as the photocatalysts in waste water treatment.

  5. High efficient ZnO nanowalnuts photocatalyst: A case study

    International Nuclear Information System (INIS)

    Yan, Feng; Zhang, Siwen; Liu, Yang; Liu, Hongfeng; Qu, Fengyu; Cai, Xue; Wu, Xiang

    2014-01-01

    Highlights: • Walnut-like ZnO nanostructures are synthesized through a facile hydrothermal method. • Morphologies and microstructures of the as-obtained ZnO products were investigated. • The photocatalytic results demonstrate that methyl orange (MO) aqueous solution can be degraded over 97% after 45 min under UV light irradiation. - Abstract: Walnut-like ZnO nanostructures are successfully synthesized through a facile hydrothermal method. The structure and morphology of the as-synthesized products were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The photocatalytic properties of ZnO nanowalnuts are investigated by photodegradating several organic dyes, such as Congo red (CR), methyl orange (MO) and eosin red aqueous solutions under UV irradiation, respectively. The results demonstrate that methyl orange (MO) aqueous solution can be degraded over 97% after 45 min under UV light irradiation. In addition, eosin red and Congo red (CR) aqueous solution degradation experiments are also conducted in the same condition, respectively. It showed that ZnO nanowalnuts represent high photocatalytic activities with a degradation efficiency of 87% for CR with 115 min of irradiation and 97% for eosin red with 55 min of irradiation. The reported ZnO products may be promising candidates as the photocatalysts in waste water treatment

  6. Ultrahigh mobility and efficient charge injection in monolayer organic thin-film transistors on boron nitride.

    Science.gov (United States)

    He, Daowei; Qiao, Jingsi; Zhang, Linglong; Wang, Junya; Lan, Tu; Qian, Jun; Li, Yun; Shi, Yi; Chai, Yang; Lan, Wei; Ono, Luis K; Qi, Yabing; Xu, Jian-Bin; Ji, Wei; Wang, Xinran

    2017-09-01

    Organic thin-film transistors (OTFTs) with high mobility and low contact resistance have been actively pursued as building blocks for low-cost organic electronics. In conventional solution-processed or vacuum-deposited OTFTs, due to interfacial defects and traps, the organic film has to reach a certain thickness for efficient charge transport. Using an ultimate monolayer of 2,7-dioctyl[1]benzothieno[3,2- b ][1]benzothiophene (C 8 -BTBT) molecules as an OTFT channel, we demonstrate remarkable electrical characteristics, including intrinsic hole mobility over 30 cm 2 /Vs, Ohmic contact with 100 Ω · cm resistance, and band-like transport down to 150 K. Compared to conventional OTFTs, the main advantage of a monolayer channel is the direct, nondisruptive contact between the charge transport layer and metal leads, a feature that is vital for achieving low contact resistance and current saturation voltage. On the other hand, bilayer and thicker C 8 -BTBT OTFTs exhibit strong Schottky contact and much higher contact resistance but can be improved by inserting a doped graphene buffer layer. Our results suggest that highly crystalline molecular monolayers are promising form factors to build high-performance OTFTs and investigate device physics. They also allow us to precisely model how the molecular packing changes the transport and contact properties.

  7. How Important Is the Organic Part of Lead Halide Perovskite Photovoltaic Cells? Efficient CsPbBr3 Cells.

    Science.gov (United States)

    Kulbak, Michael; Cahen, David; Hodes, Gary

    2015-07-02

    Hybrid organic-inorganic lead halide perovskite photovoltaic cells have already surpassed 20% conversion efficiency in the few years that they have been seriously studied. However, many fundamental questions still remain unanswered as to why they are so good. One of these is "Is the organic cation really necessary to obtain high quality cells?" In this study, we show that an all-inorganic version of the lead bromide perovskite material works equally well as the organic one, in particular generating the high open circuit voltages that are an important feature of these cells.

  8. Charge transport in highly efficient iridium cored electrophosphorescent dendrimers

    Science.gov (United States)

    Markham, Jonathan P. J.; Samuel, Ifor D. W.; Lo, Shih-Chun; Burn, Paul L.; Weiter, Martin; Bässler, Heinz

    2004-01-01

    Electrophosphorescent dendrimers are promising materials for highly efficient light-emitting diodes. They consist of a phosphorescent core onto which dendritic groups are attached. Here, we present an investigation into the optical and electronic properties of highly efficient phosphorescent dendrimers. The effect of dendrimer structure on charge transport and optical properties is studied using temperature-dependent charge-generation-layer time-of-flight measurements and current voltage (I-V) analysis. A model is used to explain trends seen in the I-V characteristics. We demonstrate that fine tuning the mobility by chemical structure is possible in these dendrimers and show that this can lead to highly efficient bilayer dendrimer light-emitting diodes with neat emissive layers. Power efficiencies of 20 lm/W were measured for devices containing a second-generation (G2) Ir(ppy)3 dendrimer with a 1,3,5-tris(2-N-phenylbenzimidazolyl)benzene electron transport layer.

  9. Very-High Efficiency, High Power Laser Diodes, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — AdTech Photonics, in collaboration with the Center for Advanced Studies in Photonics Research (CASPR) at UMBC, is pleased to submit this proposal entitled ?Very-High...

  10. [Characteristics of phosphorus uptake and use efficiency of rice with high yield and high phosphorus use efficiency].

    Science.gov (United States)

    Li, Li; Zhang, Xi-Zhou; Li, Tinx-Xuan; Yu, Hai-Ying; Ji, Lin; Chen, Guang-Deng

    2014-07-01

    A total of twenty seven middle maturing rice varieties as parent materials were divided into four types based on P use efficiency for grain yield in 2011 by field experiment with normal phosphorus (P) application. The rice variety with high yield and high P efficiency was identified by pot experiment with normal and low P applications, and the contribution rates of various P efficiencies to yield were investigated in 2012. There were significant genotype differences in yield and P efficiency of the test materials. GRLu17/AiTTP//Lu17_2 (QR20) was identified as a variety with high yield and high P efficiency, and its yields at the low and normal rates of P application were 1.96 and 1.92 times of that of Yuxiang B, respectively. The contribution rate of P accumulation to yield was greater than that of P grain production efficiency and P harvest index across field and pot experiments. The contribution rates of P accumulation and P grain production efficiency to yield were not significantly different under the normal P condition, whereas obvious differences were observed under the low P condition (66.5% and 26.6%). The minimal contribution to yield was P harvest index (11.8%). Under the normal P condition, the contribution rates of P accumulation to yield and P harvest index were the highest at the jointing-heading stage, which were 93.4% and 85.7%, respectively. In addition, the contribution rate of P accumulation to grain production efficiency was 41.8%. Under the low P condition, the maximal contribution rates of P accumulation to yield and grain production efficiency were observed at the tillering-jointing stage, which were 56.9% and 20.1% respectively. Furthermore, the contribution rate of P accumulation to P harvest index was 16.0%. The yield, P accumulation, and P harvest index of QR20 significantly increased under the normal P condition by 20.6%, 18.1% and 18.2% respectively compared with that in the low P condition. The rank of the contribution rates of P

  11. High Efficiency of Two Efficient QSDC with Authentication Is at the Cost of Their Security

    International Nuclear Information System (INIS)

    Su-Juan, Qin; Qiao-Yan, Wen; Luo-Ming, Meng; Fu-Chen, Zhu

    2009-01-01

    Two efficient protocols of quantum secure direct communication with authentication [Chin. Phys. Lett. 25 (2008) 2354] were recently proposed by Liu et al. to improve the efficiency of two protocols presented in [Phys. Rev. A 75 (2007) 026301] by four Pauli operations. We show that the high efficiency of the two protocols is at the expense of their security. The authenticator Trent can reach half the secret by a particular attack strategy in the first protocol. In the second protocol, not only Trent but also an eavesdropper outside can elicit half-information about the secret from the public declaration

  12. ITO Modification for Efficient Inverted Organic Solar Cells.

    Science.gov (United States)

    Susarova, Diana K; Akkuratov, Alexander V; Kukharenko, Andrey I; Cholakh, Seif O; Kurmaev, Ernst Z; Troshin, Pavel A

    2017-10-03

    We demonstrate a facile approach to designing transparent electron-collecting electrodes by depositing thin layers of medium and low work function metals on top of transparent conductive metal oxides (TCOs) such as ITO and FTO. The modified electrodes were fairly stable for months under ambient conditions and maintained their electrical characteristics. XPS spectroscopy data strongly suggested integration of the deposited metal in the TCO structure resulting in additional doping of the conducting oxide at the interface. Kelvin probe microscopy measurements revealed a significant decrease in the ITO work function after modification. Organic solar cells based on three different conjugated polymers have demonstrated state of the art performances in inverted device geometry using Mg- or Yb-modified ITO as electron collecting electrode. The simplicity of the proposed approach and the excellent ambient stability of the modified ITO electrodes allows one to expect their wide utilization in research laboratories and electronic industry.

  13. CHAPTER 3. High-performance Organic Photovoltaic Donor Polymers

    KAUST Repository

    Wadsworth, Andrew

    2017-11-08

    The field of organic photovoltaics has advanced a great deal over the last decade, with device efficiencies now exceeding 11%. A large part of this success can be attributed to the development of donor polymer materials, from their humble beginnings as homopolymers to the highly tuned push-pull copolymer and terpolymer materials that are now being reported on a regular basis. Through the careful use of chemical modification, it has been possible to design and synthesize a wide variety of donor polymers, allowing optimization of both the optoelectronic and structural properties of the materials. In doing so, more favourable active layer blends have been achieved and therefore significant improvements in device performance have been observed. Herein we discuss how the chemical design of donor polymers for organic photovoltaics has led to the emergence of high-performance materials.

  14. CHAPTER 3. High-performance Organic Photovoltaic Donor Polymers

    KAUST Repository

    Wadsworth, Andrew; Baran, Derya; Gorman, Jeffrey; McCulloch, Iain

    2017-01-01

    The field of organic photovoltaics has advanced a great deal over the last decade, with device efficiencies now exceeding 11%. A large part of this success can be attributed to the development of donor polymer materials, from their humble beginnings as homopolymers to the highly tuned push-pull copolymer and terpolymer materials that are now being reported on a regular basis. Through the careful use of chemical modification, it has been possible to design and synthesize a wide variety of donor polymers, allowing optimization of both the optoelectronic and structural properties of the materials. In doing so, more favourable active layer blends have been achieved and therefore significant improvements in device performance have been observed. Herein we discuss how the chemical design of donor polymers for organic photovoltaics has led to the emergence of high-performance materials.

  15. The effect of organic coating on the heterogeneous ice nucleation efficiency of mineral dust aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Moehler, O; Benz, S; Saathoff, H; Schnaiter, M; Wagner, R [Forschungszentrum Karlsruhe, Institute for Meteorology and Climate Research, 76021 Karlsruhe (Germany); Schneider, J; Walter, S [Max Planck Institute for Chemistry, 55128 Mainz (Germany); Ebert, V; Wagner, S [University of Heidelberg, Institute for Physical Chemistry, 69120 Heidelberg (Germany)], E-mail: Ottmar.Moehler@imk.fzk.de

    2008-04-15

    The effect of organic coating on the heterogeneous ice nucleation (IN) efficiency of dust particles was investigated at simulated cirrus cloud conditions in the AIDA cloud chamber of Forschungszentrum Karlsruhe. Arizona test dust (ATD) and the clay mineral illite were used as surrogates for atmospheric dust aerosols. The dry dust samples were dispersed into a 3.7 m{sup 3} aerosol vessel and either directly transferred into the 84 m{sup 3} cloud simulation chamber or coated before with the semi-volatile products from the reaction of {alpha}-pinene with ozone in order to mimic the coating of atmospheric dust particles with secondary organic aerosol (SOA) substances. The ice-active fraction was measured in AIDA expansion cooling experiments as a function of the relative humidity with respect to ice, RHi, in the temperature range from 205 to 210 K. Almost all uncoated dust particles with diameters between 0.1 and 1.0 {mu}m acted as efficient deposition mode ice nuclei at RHi between 105 and 120%. This high ice nucleation efficiency was markedly suppressed by coating with SOA. About 20% of the ATD particles coated with a SOA mass fraction of 17 wt% were ice-active at RHi between 115 and 130%, and only 10% of the illite particles coated with an SOA mass fraction of 41 wt% were ice-active at RHi between 160 and 170%. Only a minor fraction of pure SOA particles were ice-active at RHi between 150 and 190%. Strong IN activation of SOA particles was observed only at RHi above 200%, which is clearly above water saturation at the given temperature. The IN suppression and the shift of the heterogeneous IN onset to higher RHi seem to depend on the coating thickness or the fractional surface coverage of the mineral particles. The results indicate that the heterogeneous ice nucleation potential of atmospheric mineral particles may also be suppressed if they are coated with secondary organics.

  16. The effect of organic coating on the heterogeneous ice nucleation efficiency of mineral dust aerosols

    International Nuclear Information System (INIS)

    Moehler, O; Benz, S; Saathoff, H; Schnaiter, M; Wagner, R; Schneider, J; Walter, S; Ebert, V; Wagner, S

    2008-01-01

    The effect of organic coating on the heterogeneous ice nucleation (IN) efficiency of dust particles was investigated at simulated cirrus cloud conditions in the AIDA cloud chamber of Forschungszentrum Karlsruhe. Arizona test dust (ATD) and the clay mineral illite were used as surrogates for atmospheric dust aerosols. The dry dust samples were dispersed into a 3.7 m 3 aerosol vessel and either directly transferred into the 84 m 3 cloud simulation chamber or coated before with the semi-volatile products from the reaction of α-pinene with ozone in order to mimic the coating of atmospheric dust particles with secondary organic aerosol (SOA) substances. The ice-active fraction was measured in AIDA expansion cooling experiments as a function of the relative humidity with respect to ice, RHi, in the temperature range from 205 to 210 K. Almost all uncoated dust particles with diameters between 0.1 and 1.0 μm acted as efficient deposition mode ice nuclei at RHi between 105 and 120%. This high ice nucleation efficiency was markedly suppressed by coating with SOA. About 20% of the ATD particles coated with a SOA mass fraction of 17 wt% were ice-active at RHi between 115 and 130%, and only 10% of the illite particles coated with an SOA mass fraction of 41 wt% were ice-active at RHi between 160 and 170%. Only a minor fraction of pure SOA particles were ice-active at RHi between 150 and 190%. Strong IN activation of SOA particles was observed only at RHi above 200%, which is clearly above water saturation at the given temperature. The IN suppression and the shift of the heterogeneous IN onset to higher RHi seem to depend on the coating thickness or the fractional surface coverage of the mineral particles. The results indicate that the heterogeneous ice nucleation potential of atmospheric mineral particles may also be suppressed if they are coated with secondary organics

  17. An Organic D-π-A Dye for Record Efficiency Solid-State Sensitized Heterojunction Solar Cells

    KAUST Repository

    Cai, Ning; Moon, Soo-Jin; Cevey-Ha, Lê; Moehl, Thomas; Humphry-Baker, Robin; Wang, Peng; Zakeeruddin, Shaik M.; Grätzel, Michael

    2011-01-01

    The high molar absorption coefficient organic D-π-A dye C220 exhibits more than 6% certified electric power conversion efficiency at AM 1.5G solar irradiation (100 mW cm-2) in a solid-state dye-sensitized solar cell using 2,2′,7,7′-tetrakis

  18. Reduced voltage losses yield 10% efficient fullerene free organic solar cells with >1 V open circuit voltages

    KAUST Repository

    Baran, D.

    2016-11-09

    Optimization of the energy levels at the donor-acceptor interface of organic solar cells has driven their efficiencies to above 10%. However, further improvements towards efficiencies comparable with inorganic solar cells remain challenging because of high recombination losses, which empirically limit the open-circuit voltage (Voc) to typically less than 1 V. Here we show that this empirical limit can be overcome using non-fullerene acceptors blended with the low band gap polymer PffBT4T-2DT leading to efficiencies approaching 10% (9.95%). We achieve Voc up to 1.12 V, which corresponds to a loss of only Eg/q - Voc = 0.5 ± 0.01 V between the optical bandgap Eg of the polymer and Voc. This high Voc is shown to be associated with the achievement of remarkably low non-geminate and non-radiative recombination losses in these devices. Suppression of non-radiative recombination implies high external electroluminescence quantum efficiencies which are orders of magnitude higher than those of equivalent devices employing fullerene acceptors. Using the balance between reduced recombination losses and good photocurrent generation efficiencies achieved experimentally as a baseline for simulations of the efficiency potential of organic solar cells, we estimate that efficiencies of up to 20% are achievable if band gaps and fill factors are further optimized. © The Royal Society of Chemistry 2016.

  19. The emerging High Efficiency Video Coding standard (HEVC)

    International Nuclear Information System (INIS)

    Raja, Gulistan; Khan, Awais

    2013-01-01

    High definition video (HDV) is becoming popular day by day. This paper describes the performance analysis of latest upcoming video standard known as High Efficiency Video Coding (HEVC). HEVC is designed to fulfil all the requirements for future high definition videos. In this paper, three configurations (intra only, low delay and random access) of HEVC are analyzed using various 480p, 720p and 1080p high definition test video sequences. Simulation results show the superior objective and subjective quality of HEVC

  20. All-Solution-Processed Metal-Oxide-Free Flexible Organic Solar Cells with Over 10% Efficiency.

    Science.gov (United States)

    Song, Wei; Fan, Xi; Xu, Bingang; Yan, Feng; Cui, Huiqin; Wei, Qiang; Peng, Ruixiang; Hong, Ling; Huang, Jiaming; Ge, Ziyi

    2018-05-16

    All-solution-processing at low temperatures is important and desirable for making printed photovoltaic devices and also offers the possibility of a safe and cost-effective fabrication environment for the devices. Herein, an all-solution-processed flexible organic solar cell (OSC) using poly(3,4-ethylenedioxythiophene):poly-(styrenesulfonate) electrodes is reported. The all-solution-processed flexible devices yield the highest power conversion efficiency of 10.12% with high fill factor of over 70%, which is the highest value for metal-oxide-free flexible OSCs reported so far. The enhanced performance is attributed to the newly developed gentle acid treatment at room temperature that enables a high-performance PEDOT:PSS/plastic underlying substrate with a matched work function (≈4.91 eV), and the interface engineering that endows the devices with better interface contacts and improved hole mobility. Furthermore, the flexible devices exhibit an excellent mechanical flexibility, as indicated by a high retention (≈94%) of the initial efficiency after 1000 bending cycles. This work provides a simple route to fabricate high-performance all-solution-processed flexible OSCs, which is important for the development of printing, blading, and roll-to-roll technologies. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. High quality, high efficiency welding technology for nuclear power plants

    International Nuclear Information System (INIS)

    Aoki, Shigeyuki; Nagura, Yasumi

    1996-01-01

    For nuclear power plants, it is required to ensure the safety under the high reliability and to attain the high rate of operation. In the manufacture and installation of the machinery and equipment, the welding techniques which become the basis exert large influence to them. For the purpose of improving joint performance and excluding human errors, welding heat input and the number of passes have been reduced, the automation of welding has been advanced, and at present, narrow gap arc welding and high energy density welding such as electron beam welding and laser welding have been put to practical use. Also in the welding of pipings, automatic gas metal arc welding is employed. As for the welding of main machinery and equipment, there are the welding of the joints that constitute pressure boundaries, the build-up welding on the internal surfaces of pressure vessels for separating primary water from them, and the sealing welding of heating tubes and tube plates in steam generators. These weldings are explained. The welding of pipings and the state of development and application of new welding methods are reported. (K.I.)

  2. High-concentration planar microtracking photovoltaic system exceeding 30% efficiency

    Science.gov (United States)

    Price, Jared S.; Grede, Alex J.; Wang, Baomin; Lipski, Michael V.; Fisher, Brent; Lee, Kyu-Tae; He, Junwen; Brulo, Gregory S.; Ma, Xiaokun; Burroughs, Scott; Rahn, Christopher D.; Nuzzo, Ralph G.; Rogers, John A.; Giebink, Noel C.

    2017-08-01

    Prospects for concentrating photovoltaic (CPV) power are growing as the market increasingly values high power conversion efficiency to leverage now-dominant balance of system and soft costs. This trend is particularly acute for rooftop photovoltaic power, where delivering the high efficiency of traditional CPV in the form factor of a standard rooftop photovoltaic panel could be transformative. Here, we demonstrate a fully automated planar microtracking CPV system 660× concentration ratio over a 140∘ full field of view. In outdoor testing over the course of two sunny days, the system operates automatically from sunrise to sunset, outperforming a 17%-efficient commercial silicon solar cell by generating >50% more energy per unit area per day in a direct head-to-head competition. These results support the technical feasibility of planar microtracking CPV to deliver a step change in the efficiency of rooftop solar panels at a commercially relevant concentration ratio.

  3. Development of high-efficiency solar cells on silicon web

    Science.gov (United States)

    Meier, D. L.; Greggi, J.; Okeeffe, T. W.; Rai-Choudhury, P.

    1986-01-01

    Work was performed to improve web base material with a goal of obtaining solar cell efficiencies in excess of 18% (AM1). Efforts in this program are directed toward identifying carrier loss mechanisms in web silicon, eliminating or reducing these mechanisms, designing a high efficiency cell structure with the aid of numerical models, and fabricating high efficiency web solar cells. Fabrication techniques must preserve or enhance carrier lifetime in the bulk of the cell and minimize recombination of carriers at the external surfaces. Three completed cells were viewed by cross-sectional transmission electron microscopy (TEM) in order to investigate further the relation between structural defects and electrical performance of web cells. Consistent with past TEM examinations, the cell with the highest efficiency (15.0%) had no dislocations but did have 11 twin planes.

  4. Efficient Unsteady Flow Visualization with High-Order Access Dependencies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiang; Guo, Hanqi; Yuan, Xiaoru

    2016-04-19

    We present a novel high-order access dependencies based model for efficient pathline computation in unsteady flow visualization. By taking longer access sequences into account to model more sophisticated data access patterns in particle tracing, our method greatly improves the accuracy and reliability in data access prediction. In our work, high-order access dependencies are calculated by tracing uniformly-seeded pathlines in both forward and backward directions in a preprocessing stage. The effectiveness of our proposed approach is demonstrated through a parallel particle tracing framework with high-order data prefetching. Results show that our method achieves higher data locality and hence improves the efficiency of pathline computation.

  5. Efficient estimation for ergodic diffusions sampled at high frequency

    DEFF Research Database (Denmark)

    Sørensen, Michael

    A general theory of efficient estimation for ergodic diffusions sampled at high fre- quency is presented. High frequency sampling is now possible in many applications, in particular in finance. The theory is formulated in term of approximate martingale estimating functions and covers a large class...

  6. High-Efficiency Klystron Design for the CLIC Project

    CERN Document Server

    Mollard, Antoine; Peauger, Franck; Plouin, Juliette; Beunas, Armel; Marchesin, Rodolphe

    2017-01-01

    The CLIC project requests new type of RF sources for the high power conditioning of the accelerating cavities. We are working on the development of a new kind of high-efficiency klystron to fulfill this need. This work is performed under the EuCARD-2 European program and involves theoretical and experimental study of a brand new klystron concept.

  7. Efficient estimation for high similarities using odd sketches

    DEFF Research Database (Denmark)

    Mitzenmacher, Michael; Pagh, Rasmus; Pham, Ninh Dang

    2014-01-01

    . This means that Odd Sketches provide a highly space-efficient estimator for sets of high similarity, which is relevant in applications such as web duplicate detection, collaborative filtering, and association rule learning. The method extends to weighted Jaccard similarity, relevant e.g. for TF-IDF vector...... and web duplicate detection tasks....

  8. Design of High Efficiency Illumination for LED Lighting

    Directory of Open Access Journals (Sweden)

    Yong-Nong Chang

    2013-01-01

    Full Text Available A high efficiency illumination for LED street lighting is proposed. For energy saving, this paper uses Class-E resonant inverter as main electric circuit to improve efficiency. In addition, single dimming control has the best efficiency, simplest control scheme and lowest circuit cost among other types of dimming techniques. Multiple serial-connected transformers used to drive the LED strings as they can provide galvanic isolation and have the advantage of good current distribution against device difference. Finally, a prototype circuit for driving 112 W LEDs in total was built and tested to verify the theoretical analysis.

  9. An organic-inorganic hybrid coagulant containing Al, Zn and Fe (HOAZF: preparation, efficiency and mechanism of removing organic phosphorus

    Directory of Open Access Journals (Sweden)

    Y. Fu

    2018-04-01

    Full Text Available A polymeric-Al-Zn-Fe (PAZF coagulant showing high removal of pollutants has been successfully developed using a galvanized slag in earlier works, but it gave less elimination of phosphorus. To improve phosphorus removal, a hybrid organic-Al-Zn-Fe (HOAZF coagulant was prepared using PAZF and polyacrylamide (PAM as an organic additive, and then was characterized by scanning electron microscopy (SEM, infrared spectroscopy (IR, X-ray diffraction (XRD, and Zeta potential, respectively. Removing efficiency and mechanism of organophosphorus by HOAZF was probed using jar tests in treating a simulated pesticide wastewater containing dichlorvos (DDVP, compared to that by PAZF and polyaluminum chloride. The results displayed that HOAZF having relative lower Zeta potential (compared to PAZF exhibited complex surface morphology composited by Al, Zn and Fe and PAM, forming some new crystalline and amorphous substances different from that in PAZF. HOAZF gave higher removal of organophosphorus and far lower dosage than PAZF, and also posed a suitable wider pH range (pH = 7–12 for HOAZF and 10–11 for PAZF, respectively and suitable wider organophosphorus level range than PAZF. Removing organophosphorus by HOAZF was a simultaneous complex process involving a non-phase transfer of adsorption/bridging/sweeping and a phase transfer of chemical precipitation.

  10. Single Pt Atoms Confined into a Metal-Organic Framework for Efficient Photocatalysis.

    Science.gov (United States)

    Fang, Xinzuo; Shang, Qichao; Wang, Yu; Jiao, Long; Yao, Tao; Li, Yafei; Zhang, Qun; Luo, Yi; Jiang, Hai-Long

    2018-02-01

    It is highly desirable yet remains challenging to improve the dispersion and usage of noble metal cocatalysts, beneficial to charge transfer in photocatalysis. Herein, for the first time, single Pt atoms are successfully confined into a metal-organic framework (MOF), in which electrons transfer from the MOF photosensitizer to the Pt acceptor for hydrogen production by water splitting under visible-light irradiation. Remarkably, the single Pt atoms exhibit a superb activity, giving a turnover frequency of 35 h -1 , ≈30 times that of Pt nanoparticles stabilized by the same MOF. Ultrafast transient absorption spectroscopy further unveils that the single Pt atoms confined into the MOF provide highly efficient electron transfer channels and density functional theory calculations indicate that the introduction of single Pt atoms into the MOF improves the hydrogen binding energy, thus greatly boosting the photocatalytic H 2 production activity. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. A mechanistic understanding of processing additive-induced efficiency enhancement in bulk heterojunction organic solar cells

    KAUST Repository

    Schmidt, Kristin; Tassone, Christopher J.; Niskala, Jeremy R.; Yiu, Alan T.; Lee, Olivia P.; Weiss, Thomas M.; Wang, Cheng; Frechet, Jean; Beaujuge, Pierre; Toney, Michael F.

    2013-01-01

    The addition of processing additives is a widely used approach to increase power conversion efficiencies for many organic solar cells. We present how additives change the polymer conformation in the casting solution leading to a more intermixed

  12. 12 New England Organizations Honored for Outstanding Achievements in Energy Efficiency

    Science.gov (United States)

    EPA and the U.S. Department of Energy (DOE) are honoring 12 New England businesses and organizations for their commitment to saving energy, saving money, and protecting the environment through superior energy efficiency achievements.

  13. Mechanochemical transformation of an organic ligand on mineral surfaces: The efficiency of birnessite in catechol degradation

    Energy Technology Data Exchange (ETDEWEB)

    Di Leo, Paola, E-mail: pdileo@imaa.cnr.it [Consiglio Nazionale delle Ricerche - Istituto di Metodologie per l' Analisi Ambientale, C.da S. Loja, Zona Industriale, 85050 Tito Scalo (PZ) (Italy); Pizzigallo, Maria Donata Rosa [Dipartimento di Biologia e Chimica Agroforestale e Ambientale, Universita di Bari Aldo Moro, Via Amendola 165/a, 70126 Bari (Italy); Ancona, Valeria [Consiglio Nazionale delle Ricerche - Istituto di Ricerca sulle Acque, Via F. De Blasio 5, 70132 Bari (Italy); Di Benedetto, Francesco [Dipartimento di Chimica, Universita di Firenze, Via della Lastruccia, 3, 50019 Sesto Fiorentino (Italy); Mesto, Ernesto; Schingaro, Emanuela; Ventruti, Gennaro [Dipartimento di Scienze della Terra e Geoambientali, Universita di Bari Aldo Moro, Via Orabona, 4, 70125 Bari (Italy)

    2012-01-30

    Graphical abstract: . The efficiency of mechanochemical treatments in degrading CAT molecules in presence of the highly reactive phyllomanganate birnessite, and without using organic solvents, has been demonstrated in the present study. Integrating information from different techniques on solid let it possible to get a comprehensive picture of the most reliable reaction mechanism of degradation of CAT molecules onto KBi surfaces, thus allowing the individuation of specific sites in the synthesized oxides on which catechol molecules were preferentially adsorbed, and thus degraded. The degradation mechanism mainly occurs via a redox reaction. It implies the formation of a surface bidentate inner-sphere complex between the phenolic group of the organic molecules and the Mn(IV) from the birnessite structure. Structural changes occur on the MnO{sub 6} layers of birnessite as due to the mechanically induced surface reactions: reduction of Mn(IV), consequent formation of Mn(III) and new vacancies, and free Mn{sup 2+} ions production. The extent of the mechanochemical degradation of CAT onto birnessite surfaces is higher. This is a consequence of the two phenolic groups of catechol that easily reacts. Highlights: Black-Right-Pointing-Pointer A basic insight at molecular scale of the mechanically induced transformations of CAT onto birnessite is obtained. Black-Right-Pointing-Pointer The abiotic degradative mechanisms of CAT onto birnessite is provided. Black-Right-Pointing-Pointer The mechanically induced degradation of CAT mainly occurs via a redox reaction. Black-Right-Pointing-Pointer Mechanochemistry improves the efficiency of birnessite to degrade CAT. Black-Right-Pointing-Pointer The mechanochemical technique offer potentials in remediating contaminated sites. - Abstract: The aim of this work is to investigate the efficiency of the phyllomanganate birnessite in degrading catechol after mechanochemical treatments. A synthesized birnessite and the organic molecule were

  14. Efficient charge generation by relaxed charge-transfer states at organic interfaces

    KAUST Repository

    Vandewal, Koen

    2013-11-17

    Interfaces between organic electron-donating (D) and electron-accepting (A) materials have the ability to generate charge carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT1) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold via weakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer:fullerene, small-molecule:C60 and polymer:polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT1 are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy. © 2014 Macmillan Publishers Limited.

  15. Efficient charge generation by relaxed charge-transfer states at organic interfaces

    KAUST Repository

    Vandewal, Koen; Albrecht, Steve N.; Hoke, Eric T.; Graham, Kenneth; Widmer, Johannes; Douglas, Jessica D.; Schubert, Marcel; Mateker, William R.; Bloking, Jason T.; Burkhard, George F.; Sellinger, Alan; Frechet, Jean; Amassian, Aram; Riede, Moritz Kilian; McGehee, Michael D.; Neher, Dieter; Salleo, Alberto

    2013-01-01

    Interfaces between organic electron-donating (D) and electron-accepting (A) materials have the ability to generate charge carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT1) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold via weakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer:fullerene, small-molecule:C60 and polymer:polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT1 are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy. © 2014 Macmillan Publishers Limited.

  16. Efficient organic light-emitting devices with platinum-complex emissive layer

    KAUST Repository

    Yang, Xiaohui

    2011-01-18

    We report efficient organic light-emitting devices having a platinum-complex emissive layer with the peak external quantum efficiency of 17.5% and power efficiency of 45 lm W−1. Variation in the device performance with platinum-complex layer thickness can be attributed to the interplay between carrier recombination and intermolecular interactions in the layer. Efficient white devices using double platinum-complex layers show the external quantum efficiency of 10%, the Commission Internationale d’Énclairage coordinates of (0.42, 0.41), and color rendering index of 84 at 1000 cd m−2.

  17. Efficient organic light-emitting devices with platinum-complex emissive layer

    KAUST Repository

    Yang, Xiaohui; Wu, Fang-Iy; Haverinen, Hanna; Li, Jian; Cheng, Chien-Hong; Jabbour, Ghassan E.

    2011-01-01

    We report efficient organic light-emitting devices having a platinum-complex emissive layer with the peak external quantum efficiency of 17.5% and power efficiency of 45 lm W−1. Variation in the device performance with platinum-complex layer thickness can be attributed to the interplay between carrier recombination and intermolecular interactions in the layer. Efficient white devices using double platinum-complex layers show the external quantum efficiency of 10%, the Commission Internationale d’Énclairage coordinates of (0.42, 0.41), and color rendering index of 84 at 1000 cd m−2.

  18. Efficiency of swimming of micro-organism and singularity in shape space

    OpenAIRE

    Kawamura, Masako

    1996-01-01

    Micro-organisms can be classified into three different types according to their size. We study the efficiency of the swimming of micro-organism in two dimensional fluid as a device for helping the explanation of this hierarchy in the size. We show that the efficiency of flagellate becomes unboundedly large, whereas that of ciliate has the upper bound. The unboundedness is related to the curious feature of the shape space, that is, a singularity at the basic shape of flagellate.

  19. High efficiency heat transport and power conversion system for cascade

    International Nuclear Information System (INIS)

    Maya, I.; Bourque, R.F.; Creedon, R.L.; Schultz, K.R.

    1985-02-01

    The Cascade ICF reactor features a flowing blanket of solid BeO and LiAlO 2 granules with very high temperature capability (up to approx. 2300 K). The authors present here the design of a high temperature granule transport and heat exchange system, and two options for high efficiency power conversion. The centrifugal-throw transport system uses the peripheral speed imparted to the granules by the rotating chamber to effect granule transport and requires no additional equipment. The heat exchanger design is a vacuum heat transfer concept utilizing gravity-induced flow of the granules over ceramic heat exchange surfaces. A reference Brayton power cycle is presented which achieves 55% net efficiency with 1300 K peak helium temperature. A modified Field steam cycle (a hybrid Rankine/Brayton cycle) is presented as an alternate which achieves 56% net efficiency

  20. Highly Efficient Coherent Optical Memory Based on Electromagnetically Induced Transparency

    Science.gov (United States)

    Hsiao, Ya-Fen; Tsai, Pin-Ju; Chen, Hung-Shiue; Lin, Sheng-Xiang; Hung, Chih-Chiao; Lee, Chih-Hsi; Chen, Yi-Hsin; Chen, Yong-Fan; Yu, Ite A.; Chen, Ying-Cheng

    2018-05-01

    Quantum memory is an important component in the long-distance quantum communication based on the quantum repeater protocol. To outperform the direct transmission of photons with quantum repeaters, it is crucial to develop quantum memories with high fidelity, high efficiency and a long storage time. Here, we achieve a storage efficiency of 92.0 (1.5)% for a coherent optical memory based on the electromagnetically induced transparency scheme in optically dense cold atomic media. We also obtain a useful time-bandwidth product of 1200, considering only storage where the retrieval efficiency remains above 50%. Both are the best record to date in all kinds of schemes for the realization of optical memory. Our work significantly advances the pursuit of a high-performance optical memory and should have important applications in quantum information science.

  1. Controlling excitons. Concepts for phosphorescent organic LEDs at high brightness

    Energy Technology Data Exchange (ETDEWEB)

    Reineke, Sebastian

    2009-11-15

    This work focusses on the high brightness performance of phosphorescent organic light-emitting diodes (OLEDs). The use of phosphorescent emitter molecules in OLEDs is essential to realize internal electron-photon conversion efficiencies of 100 %. However, due to their molecular nature, the excited triplet states have orders of magnitude longer time constants compared to their fluorescent counterparts which, in turn, strongly increases the probability of bimolecular annihilation. As a consequence, the efficiencies of phosphorescent OLEDs decline at high brightness - an effect known as efficiency roll-off, for which it has been shown to be dominated by triplet-triplet annihilation (TTA). In this work, TTA of the archetype phosphorescent emitter Ir(ppy){sub 3} is investigated in time-resolved photoluminescence experiments. For the widely used mixed system CBP:Ir(ppy){sub 3}, host-guest TTA - an additional unwanted TTA channel - is experimentally observed at high excitation levels. By using matrix materials with higher triplet energies, this effect is efficiently suppressed, however further studies show that the efficiency roll-off of Ir(ppy)3 is much more pronounced than predicted by a model based on Foerster-type energy transfer, which marks the intrinsic limit for TTA. These results suggest that the emitter molecules show a strong tendency to form aggregates in the mixed film as the origin for enhanced TTA. Transmission electron microscopy images of Ir(ppy){sub 3} doped mixed films give direct proof of emitter aggregates. Based on these results, two concepts are developed that improve the high brightness performance of OLEDs. In a first approach, thin intrinsic matrix interlayers are incorporated in the emission layer leading to a one-dimensional exciton confinement that suppresses exciton migration and, consequently, TTA. The second concept reduces the efficiency roll-off by using an emitter molecule with slightly different chemical structure, i.e. Ir(ppy){sub 2

  2. Geometric light trapping with a V-trap for efficient organic solar cells

    KAUST Repository

    Kim, Soo Jin

    2013-03-14

    The efficiency of today’s most efficient organic solar cells is primarily limited by the ability of the active layer to absorb all the sunlight. While internal quantum efficiencies exceeding 90% are common, the external quantum efficiency rarely exceeds 70%. Light trapping techniques that increase the ability of a given active layer to absorb light are common in inorganic solar cells but have only been applied to organic solar cells with limited success. Here, we analyze the light trapping mechanism for a cell with a V-shape substrate configuration and demonstrate significantly improved photon absorption in an 5.3%-efficient PCDTBT:PC70BM bulk heterojunction polymer solar cell. The measured short circuit current density improves by 29%, in agreement with model predictions, and the power conversion efficiency increases to 7.2%, a 35% improvement over the performance in the absence of a light trap.

  3. Multiple regression models for the prediction of the maximum obtainable thermal efficiency of organic Rankine cycles

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Pierobon, Leonardo; Wronski, Jorrit

    2014-01-01

    Much attention is focused on increasing the energy efficiency to decrease fuel costs and CO2 emissions throughout industrial sectors. The ORC (organic Rankine cycle) is a relatively simple but efficient process that can be used for this purpose by converting low and medium temperature waste heat ...

  4. Low Cost, High Efficiency, High Pressure Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Mark Leavitt

    2010-03-31

    A technical and design evaluation was carried out to meet DOE hydrogen fuel targets for 2010. These targets consisted of a system gravimetric capacity of 2.0 kWh/kg, a system volumetric capacity of 1.5 kWh/L and a system cost of $4/kWh. In compressed hydrogen storage systems, the vast majority of the weight and volume is associated with the hydrogen storage tank. In order to meet gravimetric targets for compressed hydrogen tanks, 10,000 psi carbon resin composites were used to provide the high strength required as well as low weight. For the 10,000 psi tanks, carbon fiber is the largest portion of their cost. Quantum Technologies is a tier one hydrogen system supplier for automotive companies around the world. Over the course of the program Quantum focused on development of technology to allow the compressed hydrogen storage tank to meet DOE goals. At the start of the program in 2004 Quantum was supplying systems with a specific energy of 1.1-1.6 kWh/kg, a volumetric capacity of 1.3 kWh/L and a cost of $73/kWh. Based on the inequities between DOE targets and Quantum’s then current capabilities, focus was placed first on cost reduction and second on weight reduction. Both of these were to be accomplished without reduction of the fuel system’s performance or reliability. Three distinct areas were investigated; optimization of composite structures, development of “smart tanks” that could monitor health of tank thus allowing for lower design safety factor, and the development of “Cool Fuel” technology to allow higher density gas to be stored, thus allowing smaller/lower pressure tanks that would hold the required fuel supply. The second phase of the project deals with three additional distinct tasks focusing on composite structure optimization, liner optimization, and metal.

  5. High Efficient Bidirectional Battery Converter for residential PV Systems

    DEFF Research Database (Denmark)

    Pham, Cam; Kerekes, Tamas; Teodorescu, Remus

    2012-01-01

    Photovoltaic (PV) installation is suited for the residential environment and the generation pattern follows the distribution of residential power consumption in daylight hours. In the cases of unbalance between generation and demand, the Smart PV with its battery storage can absorb or inject...... the power to balance it. High efficient bidirectional converter for the battery storage is required due high system cost and because the power is processed twice. A 1.5kW prototype is designed and built with CoolMOS and SiC diodes, >;95% efficiency has been obtained with 200 kHz hard switching....

  6. High brightness diode-pumped organic solid-state laser

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhuang; Mhibik, Oussama; Nafa, Malik; Chénais, Sébastien; Forget, Sébastien, E-mail: sebastien.forget@univ-paris13.fr [Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430, Villetaneuse (France); CNRS, UMR 7538, LPL, F-93430, Villetaneuse (France)

    2015-02-02

    High-power, diffraction-limited organic solid-state laser operation has been achieved in a vertical external cavity surface-emitting organic laser (VECSOL), pumped by a low-cost compact blue laser diode. The diode-pumped VECSOLs were demonstrated with various dyes in a polymer matrix, leading to laser emissions from 540 nm to 660 nm. Optimization of both the pump pulse duration and output coupling leads to a pump slope efficiency of 11% for a DCM based VECSOLs. We report output pulse energy up to 280 nJ with 100 ns long pump pulses, leading to a peak power of 3.5 W in a circularly symmetric, diffraction-limited beam.

  7. Innovative-Simplified Nuclear Power Plant Efficiency Evaluation with High-Efficiency Steam Injector System

    International Nuclear Information System (INIS)

    Shoji, Goto; Shuichi, Ohmori; Michitsugu, Mori

    2006-01-01

    It is possible to establish simplified system with reduced space and total equipment weight using high-efficiency Steam Injectors (SI) instead of low-pressure feedwater heaters in Nuclear Power Plant (NPP). The SI works as a heat exchanger through direct contact between feedwater from condensers and extracted steam from turbines. It can get higher pressure than supplied steam pressure. The maintenance and reliability are still higher than the feedwater ones because SI has no movable parts. This paper describes the analysis of the heat balance, plant efficiency and the operation of this Innovative-Simplified NPP with high-efficiency SI. The plant efficiency and operation are compared with the electric power of 1100 MWe-class BWR system and the Innovative-Simplified BWR system with SI. The SI model is adapted into the heat balance simulator with a simplified model. The results show that plant efficiencies of the Innovated-Simplified BWR system are almost equal to original BWR ones. The present research is one of the projects that are carried out by Tokyo Electric Power Company, Toshiba Corporation, and six Universities in Japan, funded from the Institute of Applied Energy (IAE) of Japan as the national public research-funded program. (authors)

  8. Learning Organizations in High Reliability Industries

    International Nuclear Information System (INIS)

    Schwalbe, D.; Wächter, C.

    2016-01-01

    Full text: Humans make mistakes. Sometimes we learn from them. In a high reliability organization we have to learn before an error leads to an incident (or even accident). Therefore the “human factor” is most important as most of the time the human is the last line of defense. The “human factor” is more than communication or leadership skills. At the end, it is the personal attitude. This attitude has to be safety minded. And this attitude has to be self-reflected continuously. Moreover, feedback from others is urgently needed to improve one’s personal skills daily and learn from our own experience as well as from others. (author

  9. A metamaterial electromagnetic energy rectifying surface with high harvesting efficiency

    Directory of Open Access Journals (Sweden)

    Xin Duan

    2016-12-01

    Full Text Available A novel metamaterial rectifying surface (MRS for electromagnetic energy capture and rectification with high harvesting efficiency is presented. It is fabricated on a three-layer printed circuit board, which comprises an array of periodic metamaterial particles in the shape of mirrored split rings, a metal ground, and integrated rectifiers employing Schottky diodes. Perfect impedance matching is engineered at two interfaces, i.e. one between free space and the surface, and the other between the metamaterial particles and the rectifiers, which are connected through optimally positioned vias. Therefore, the incident electromagnetic power is captured with almost no reflection by the metamaterial particles, then channeled maximally to the rectifiers, and finally converted to direct current efficiently. Moreover, the rectifiers are behind the metal ground, avoiding the disturbance of high power incident electromagnetic waves. Such a MRS working at 2.45 GHz is designed, manufactured and measured, achieving a harvesting efficiency up to 66.9% under an incident power density of 5 mW/cm2, compared with a simulated efficiency of 72.9%. This high harvesting efficiency makes the proposed MRS an effective receiving device in practical microwave power transmission applications.

  10. A metamaterial electromagnetic energy rectifying surface with high harvesting efficiency

    Science.gov (United States)

    Duan, Xin; Chen, Xing; Zhou, Lin

    2016-12-01

    A novel metamaterial rectifying surface (MRS) for electromagnetic energy capture and rectification with high harvesting efficiency is presented. It is fabricated on a three-layer printed circuit board, which comprises an array of periodic metamaterial particles in the shape of mirrored split rings, a metal ground, and integrated rectifiers employing Schottky diodes. Perfect impedance matching is engineered at two interfaces, i.e. one between free space and the surface, and the other between the metamaterial particles and the rectifiers, which are connected through optimally positioned vias. Therefore, the incident electromagnetic power is captured with almost no reflection by the metamaterial particles, then channeled maximally to the rectifiers, and finally converted to direct current efficiently. Moreover, the rectifiers are behind the metal ground, avoiding the disturbance of high power incident electromagnetic waves. Such a MRS working at 2.45 GHz is designed, manufactured and measured, achieving a harvesting efficiency up to 66.9% under an incident power density of 5 mW/cm2, compared with a simulated efficiency of 72.9%. This high harvesting efficiency makes the proposed MRS an effective receiving device in practical microwave power transmission applications.

  11. High Performance Healthcare Buildings: A Roadmap to Improved Energy Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Brett C.; Tschudi, William F.

    2009-09-08

    This document presents a road map for improving the energy efficiency of hospitals and other healthcare facilities. The report compiles input from a broad array of experts in healthcare facility design and operations. The initial section lists challenges and barriers to efficiency improvements in healthcare. Opportunities are organized around the following ten themes: understanding and benchmarking energy use; best practices and training; codes and standards; improved utilization of existing HVAC designs and technology; innovation in HVAC design and technology; electrical system design; lighting; medical equipment and process loads; economic and organizational issues; and the design of next generation sustainable hospitals. Achieving energy efficiency will require a broad set of activities including research, development, deployment, demonstration, training, etc., organized around 48 specific objectives. Specific activities are prioritized in consideration of potential impact, likelihood of near- or mid-term feasibility and anticipated cost-effectiveness. This document is intended to be broad in consideration though not exhaustive. Opportunities and needs are identified and described with the goal of focusing efforts and resources.

  12. Screening of High Temperature Organic Materials for Future Stirling Convertors

    Science.gov (United States)

    Shin, Euy-sik E.; Scheiman, Daniel A.

    2017-01-01

    Along with major advancement of Stirling-based convertors, high temperature organics are needed to develop future higher temperature convertors for much improved efficiencies as well as to improve the margin of reliability for the current SOA (State-of-the-Art) convertors. The higher temperature capabilities would improve robustness of the convertors and also allow them to be used in additional missions, particularly ones that require a Venus flyby for a gravity assist. Various organic materials have been employed as essential components in the convertor for their unique properties and functions such as bonding, potting, sealing, thread locking, insulation, and lubrication. The Stirling convertor radioisotope generators have been developed for potential future space applications including Lunar/Mars surface power or a variety of spacecraft and vehicles, especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration. Thus, performance, durability, and reliability of the organics should be critically evaluated in terms of every possible material structure-process-service environment relations based on the potential mission specifications. The initial efforts in screening the high temperature candidates focused on the most susceptible organics, such as adhesive, potting compound, O-ring, shrink tubing, and thread locker materials in conjunction with commercially available materials. More systematic and practical test methodologies that were developed and optimized based on the extensive organic evaluations and validations performed for various Stirling convertor types were employed to determine thermal stability, outgassing, and material compatibility of the selected organic candidates against their functional requirements. Processing and fabrication conditions and procedures were also optimized. This report presents results of the three-step candidate evaluation processes, their application limitations, and the final selection

  13. Plasmon enhanced power conversion efficiency in inverted bulk heterojunction organic solar cell

    Science.gov (United States)

    Mohan, Minu; Ramkumar, S.; Namboothiry, Manoj A. G.

    2017-08-01

    P3HT:PCBM is one of the most studied polymer-fullerene system. However the reported power conversion efficiency (PCE) values falls within the range of 4% to 5%. The thin film architecture in OPVs exhibits low PCE compared to inorganic photovoltaic cells. This is mainly due to the low exciton diffusion length that limits the active layer thickness which in turn reduces the absorption of incident light. Several strategies are adapted in order to increase the absorption in the active layer without increasing the film thickness. Inclusion of metal nanoparticles into the polymer layer of bulk heterojunction (BHJ) solar cells is one of the promising methods. Incorporation of metal nanostructures increases the absorption of organic materials due to the high electromagnetic field strength in the vicinity of the excited surface plasmons. In this work, we used 60 nm Au plasmonic structures to improve the efficiency of organic solar cell. The prepared metal nano structures were characterized through scanning electron microscopy (SEM), and UV-Visible spectroscopy techniques. These prepared metallic nanoparticles can be incorporated either into the electron transport layer (ETL) or into the active P3HT:PC71BM layer. The effect of incorporation of plasmonic gold (Au) nanoparticle in the inverted bulk heterojunction organic photovoltaic cells (OPVs) of P3HT:PC71BM fabricated in ambient air condition is in progress. Initial studies shows an 8.5% enhancement in the PCE with the incorporation of Au nanoparticles under AM1.5G light of intensity 1 Sun.

  14. Nano-particle based scattering layers for optical efficiency enhancement of organic light-emitting diodes and organic solar cells

    Science.gov (United States)

    Chang, Hong-Wei; Lee, Jonghee; Hofmann, Simone; Hyun Kim, Yong; Müller-Meskamp, Lars; Lüssem, Björn; Wu, Chung-Chih; Leo, Karl; Gather, Malte C.

    2013-05-01

    The performance of both organic light-emitting diodes (OLEDs) and organic solar cells (OSC) depends on efficient coupling between optical far field modes and the emitting/absorbing region of the device. Current approaches towards OLEDs with efficient light-extraction often are limited to single-color emission or require expensive, non-standard substrates or top-down structuring, which reduces compatibility with large-area light sources. Here, we report on integrating solution-processed nano-particle based light-scattering films close to the active region of organic semiconductor devices. In OLEDs, these films efficiently extract light that would otherwise remain trapped in the device. Without additional external outcoupling structures, translucent white OLEDs containing these scattering films achieve luminous efficacies of 46 lm W-1 and external quantum efficiencies of 33% (both at 1000 cd m-2). These are by far the highest numbers ever reported for translucent white OLEDs and the best values in the open literature for any white device on a conventional substrate. By applying additional light-extraction structures, 62 lm W-1 and 46% EQE are reached. Besides universally enhancing light-extraction in various OLED configurations, including flexible, translucent, single-color, and white OLEDs, the nano-particle scattering film boosts the short-circuit current density in translucent organic solar cells by up to 70%.

  15. A Low VSWR and High Efficiency Waveguide Feed Antenna Array

    Directory of Open Access Journals (Sweden)

    Zhao Xiao-Fang

    2018-01-01

    Full Text Available A low VSWR and high efficiency antenna array operating in the Ku band for satellite communications is presented in this paper. To achieve high radiation efficiency and broad enough bandwidth, all-metal radiation elements and full-corporate waveguide feeding network are employed. As the general milling method is used in the multilayer antenna array fabrication, the E-plane waveguide feeding network is adopted here to suppress the wave leakage caused by the imperfect connectivity between adjacent layers. A 4 × 8 elements array prototype was fabricated and tested for verification. The measured results of proposed antenna array show bandwidth of 6.9% (13.9–14.8 GHz for VSWR < 1.5. Furthermore, antenna gain and efficiency of higher than 22.2 dBi and 80% are also exhibited, respectively.

  16. Potential high efficiency solar cells: Applications from space photovoltaic research

    Science.gov (United States)

    Flood, D. J.

    1986-01-01

    NASA involvement in photovoltaic energy conversion research development and applications spans over two decades of continuous progress. Solar cell research and development programs conducted by the Lewis Research Center's Photovoltaic Branch have produced a sound technology base not only for the space program, but for terrestrial applications as well. The fundamental goals which have guided the NASA photovoltaic program are to improve the efficiency and lifetime, and to reduce the mass and cost of photovoltaic energy conversion devices and arrays for use in space. The major efforts in the current Lewis program are on high efficiency, single crystal GaAs planar and concentrator cells, radiation hard InP cells, and superlattice solar cells. A brief historical perspective of accomplishments in high efficiency space solar cells will be given, and current work in all of the above categories will be described. The applicability of space cell research and technology to terrestrial photovoltaics will be discussed.

  17. The thermodynamic characteristics of high efficiency, internal-combustion engines

    International Nuclear Information System (INIS)

    Caton, Jerald A.

    2012-01-01

    Highlights: ► The thermodynamics of an automotive engine are determined using a cycle simulation. ► The net indicated thermal efficiency increased from 37.0% to 53.9%. ► High compression ratio, lean mixtures and high EGR were the important features. ► Efficiency increased due to lower heat losses, and increased work conversion. ► The nitric oxides were essentially zero due to the low combustion temperatures. - Abstract: Recent advancements have demonstrated new combustion modes for internal combustion engines that exhibit low nitric oxide emissions and high thermal efficiencies. These new combustion modes involve various combinations of stratification, lean mixtures, high levels of EGR, multiple injections, variable valve timings, two fuels, and other such features. Although the exact combination of these features that provides the best design is not yet clear, the results (low emissions with high efficiencies) are of major interest. The current work is directed at determining some of the fundamental thermodynamic reasons for the relatively high efficiencies and to quantify these factors. Both the first and second laws are used in this assessment. An automotive engine (5.7 l) which included some of the features mentioned above (e.g., high compression ratios, lean mixtures, and high EGR) was evaluated using a thermodynamic cycle simulation. These features were examined for a moderate load (bmep = 900 kPa), moderate speed (2000 rpm) condition. By the use of lean operation, high EGR levels, high compression ratio and other features, the net indicated thermal efficiency increased from 37.0% to 53.9%. These increases are explained in a step-by-step fashion. The major reasons for these improvements include the higher compression ratio and the dilute charge (lean mixture, high EGR). The dilute charge resulted in lower temperatures which in turn resulted in lower heat loss. In addition, the lower temperatures resulted in higher ratios of the specific heats which

  18. One-Step Borylation of 1,3-Diaryloxybenzenes Towards Efficient Materials for Organic Light-Emitting Diodes.

    Science.gov (United States)

    Hirai, Hiroki; Nakajima, Kiichi; Nakatsuka, Soichiro; Shiren, Kazushi; Ni, Jingping; Nomura, Shintaro; Ikuta, Toshiaki; Hatakeyama, Takuji

    2015-11-09

    The development of a one-step borylation of 1,3-diaryloxybenzenes, yielding novel boron-containing polycyclic aromatic compounds, is reported. The resulting boron-containing compounds possess high singlet-triplet excitation energies as a result of localized frontier molecular orbitals induced by boron and oxygen. Using these compounds as a host material, we successfully prepared phosphorescent organic light-emitting diodes exhibiting high efficiency and adequate lifetimes. Moreover, using the present one-step borylation, we succeeded in the synthesis of an efficient, thermally activated delayed fluorescence emitter and boron-fused benzo[6]helicene. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Synergetic electrode architecture for efficient graphene-based flexible organic light-emitting diodes.

    Science.gov (United States)

    Lee, Jaeho; Han, Tae-Hee; Park, Min-Ho; Jung, Dae Yool; Seo, Jeongmin; Seo, Hong-Kyu; Cho, Hyunsu; Kim, Eunhye; Chung, Jin; Choi, Sung-Yool; Kim, Taek-Soo; Lee, Tae-Woo; Yoo, Seunghyup

    2016-06-02

    Graphene-based organic light-emitting diodes (OLEDs) have recently emerged as a key element essential in next-generation displays and lighting, mainly due to their promise for highly flexible light sources. However, their efficiency has been, at best, similar to that of conventional, indium tin oxide-based counterparts. We here propose an ideal electrode structure based on a synergetic interplay of high-index TiO2 layers and low-index hole-injection layers sandwiching graphene electrodes, which results in an ideal situation where enhancement by cavity resonance is maximized yet loss to surface plasmon polariton is mitigated. The proposed approach leads to OLEDs exhibiting ultrahigh external quantum efficiency of 40.8 and 62.1% (64.7 and 103% with a half-ball lens) for single- and multi-junction devices, respectively. The OLEDs made on plastics with those electrodes are repeatedly bendable at a radius of 2.3 mm, partly due to the TiO2 layers withstanding flexural strain up to 4% via crack-deflection toughening.

  20. Doping Polymer Semiconductors by Organic Salts: Toward High-Performance Solution-Processed Organic Field-Effect Transistors.

    Science.gov (United States)

    Hu, Yuanyuan; Rengert, Zachary D; McDowell, Caitlin; Ford, Michael J; Wang, Ming; Karki, Akchheta; Lill, Alexander T; Bazan, Guillermo C; Nguyen, Thuc-Quyen

    2018-04-24

    Solution-processed organic field-effect transistors (OFETs) were fabricated with the addition of an organic salt, trityl tetrakis(pentafluorophenyl)borate (TrTPFB), into thin films of donor-acceptor copolymer semiconductors. The performance of OFETs is significantly enhanced after the organic salt is incorporated. TrTPFB is confirmed to p-dope the organic semiconductors used in this study, and the doping efficiency as well as doping physics was investigated. In addition, systematic electrical and structural characterizations reveal how the doping enhances the performance of OFETs. Furthermore, it is shown that this organic salt doping method is feasible for both p- and n-doping by using different organic salts and, thus, can be utilized to achieve high-performance OFETs and organic complementary circuits.

  1. A nuclear standard high-efficiency adsorber for iodine

    International Nuclear Information System (INIS)

    Wang Jianmin; Qian Yinge

    1988-08-01

    The structure of a nuclear standard high-efficiency adsorber, adsorbent and its performance are introduced. The performance and structure were compared with the same kind product of other firms. The results show that the leakage rate is less than 0.005%

  2. Efficiency criteria for high reliability measured system structures

    International Nuclear Information System (INIS)

    Sal'nikov, N.L.

    2012-01-01

    The procedures of structural redundancy are usually used to develop high reliability measured systems. To estimate efficiency of such structures the criteria to compare different systems has been developed. So it is possible to develop more exact system by inspection of redundant system data unit stochastic characteristics in accordance with the developed criteria [ru

  3. Optimization of high-efficiency components; Optimieren auf hohem Niveau

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Eva

    2009-07-01

    High efficiency is a common feature of modern current inverters and is not a unique selling proposition. Other factors that influence the buyer's decision are cost reduction, reliability and service, optimum grid integration, and the challenges of the competitive thin film technology. (orig.)

  4. Orion, a high efficiency 4π neutron detector

    International Nuclear Information System (INIS)

    Crema, E.; Piasecki, E.; Wang, X.M.; Doubre, H.; Galin, J.; Guerreau, D.; Pouthas, J.; Saint-Laurent, F.

    1990-01-01

    In intermediate energy heavy ion collisions the multiplicity of emitted neutrons is strongly connected to energy dissipation and to impact parameter. We present the 4π detector ORION, a high efficiency liquid scintillator detector which permits to get information on the multiplicity of neutrons measured event-wise and on the spatial distribution of these neutrons [fr

  5. High efficiency hydrodynamic DNA fragmentation in a bubbling system

    NARCIS (Netherlands)

    Li, Lanhui; Jin, Mingliang; Sun, Chenglong; Wang, Xiaoxue; Xie, Shuting; Zhou, Guofu; Van Den Berg, Albert; Eijkel, Jan C.T.; Shui, Lingling

    2017-01-01

    DNA fragmentation down to a precise fragment size is important for biomedical applications, disease determination, gene therapy and shotgun sequencing. In this work, a cheap, easy to operate and high efficiency DNA fragmentation method is demonstrated based on hydrodynamic shearing in a bubbling

  6. High efficiency confinement mode by electron cyclotron heating

    International Nuclear Information System (INIS)

    Funahashi, Akimasa

    1987-01-01

    In the medium size nuclear fusion experiment facility JFT-2M in the Japan Atomic Energy Research Institute, the research on the high efficiency plasma confinement mode has been advanced, and in the experiment in June, 1987, the formation of a high efficiency confinement mode was successfully controlled by electron cyclotron heating, for the first time in the world. This result further advanced the control of the formation of a high efficiency plasma confinement mode and the elucidation of the physical mechanism of that mode, and promoted the research and development of the plasma heating by electron cyclotron heating. In this paper, the recent results of the research on a high efficiency confinement mode at the JFT-2M are reported, and the role of the JFT-2M and the experiment on the improvement of core plasma performance are outlined. Now the plasma temperature exceeding 100 million deg C has been attained in large tokamaks, and in medium size facilities, the various measures for improving confinement performance are to be brought forth and their scientific basis is elucidated to assist large facilities. The JFT-2M started the operation in April, 1983, and has accumulated the results smoothly since then. (Kako, I.)

  7. Super Boiler: First Generation, Ultra-High Efficiency Firetube Boiler

    Energy Technology Data Exchange (ETDEWEB)

    None

    2006-06-01

    This factsheet describes a research project whose goal is to develop and demonstrate a first-generation ultra-high-efficiency, ultra-low emissions, compact gas-fired package boiler (Super Boiler), and formulate a long-range RD&D plan for advanced boiler technology out to the year 2020.

  8. High-efficient solar cells with porous silicon

    International Nuclear Information System (INIS)

    Migunova, A.A.

    2002-01-01

    It has been shown that the porous silicon is multifunctional high-efficient coating on silicon solar cells, modifies its surface and combines in it self antireflection and passivation properties., The different optoelectronic effects in solar cells with porous silicon were considered. The comparative parameters of uncovered photodetectors also solar cells with porous silicon and other coatings were resulted. (author)

  9. A Review on the Efficiency of Graphene-Based BHJ Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Alejandro Manzano-Ramírez

    2015-01-01

    Full Text Available Graphene, a material composed of one-atom-thick planar sheets of sp2-bonded carbon atoms with a two-dimensional honeycomb structure, has been proposed for many applications due to its remarkable electronic, optical, thermal, and mechanical properties. Its high transparency, conductivity, flexibility, and abundance make it an excellent material to be applied in the field of organic photovoltaic cells, especially as a replacement for transparent conducting oxide electrodes. However, graphene has been demonstrated to be useful not only as substitute for indium tin oxide electrodes, but also as cathode, electron acceptor, hole transport, and electron extraction material. Thus, in this work, we summarize and discuss the efficiency of bulk heterojunction devices using graphene as a main constituent.

  10. Understanding Energy Loss in Organic Solar Cells: Toward a New Efficiency Regime

    KAUST Repository

    Menke, S. Matthew; Ran, Niva A.; Bazan, Guillermo C.; Friend, Richard H.

    2017-01-01

    Reducing energy and voltage loss is an imperative area of improvement for the design of organic solar cells (OSCs). Both in the context of charge generation and charge recombination, significant amounts of energy are lost even in state-of-the-art OSCs compared with their inorganic counterparts. Through a set of recent examples, however, we show that (1) charge generation can proceed with high quantum efficiency even in the absence of an offset energy at the donor-acceptor interface and (2) non-radiative charge recombination may be mitigated by considering systems with distinct properties of the interfacial charge-transfer state. To capitalize on these recent advances in understanding, we provide three actionable paths forward that aim to better identify, process, and characterize low energy loss systems: incorporating consistent and accurate measurements for energy levels, moving away from photoluminescence quenching, and exploring blends with reduced miscibility.

  11. Understanding Energy Loss in Organic Solar Cells: Toward a New Efficiency Regime

    KAUST Repository

    Menke, S. Matthew

    2017-10-19

    Reducing energy and voltage loss is an imperative area of improvement for the design of organic solar cells (OSCs). Both in the context of charge generation and charge recombination, significant amounts of energy are lost even in state-of-the-art OSCs compared with their inorganic counterparts. Through a set of recent examples, however, we show that (1) charge generation can proceed with high quantum efficiency even in the absence of an offset energy at the donor-acceptor interface and (2) non-radiative charge recombination may be mitigated by considering systems with distinct properties of the interfacial charge-transfer state. To capitalize on these recent advances in understanding, we provide three actionable paths forward that aim to better identify, process, and characterize low energy loss systems: incorporating consistent and accurate measurements for energy levels, moving away from photoluminescence quenching, and exploring blends with reduced miscibility.

  12. [Effects of phosphorus sources on phosphorus fractions in rhizosphere soil of wild barley genotypes with high phosphorus utilization efficiency].

    Science.gov (United States)

    Cai, Qiu-Yan; Zhang, Xi-Zhou; Li, Ting-Xuan; Chen, Guang-Deng

    2014-11-01

    High P-efficiency (IS-22-30, IS-22-25) and low P-efficiency (IS-07-07) wild barley cultivars were chosen to evaluate characteristics of phosphorus uptake and utilization, and properties of phosphorus fractions in rhizosphere and non-rhizosphere in a pot experiment with 0 (CK) and 30 mg P · kg(-1) supplied as only Pi (KH2PO4), only Po (phytate) or Pi + Po (KH2PO4+ phytate). The results showed that dry matter and phosphorus accumulation of wild barley in the different treatments was ranked as Pi > Pi + Po > Po > CK. In addition, dry matter yield and phosphorus uptake of wild barley with high P-efficiency exhibited significantly greater than that with low P-efficiency. The concentration of soil available phosphorus was significantly different after application of different phosphorus sources, which was presented as Pi > Pi + Po > Po. The concentration of soil available phosphorus in high P-efficiency wild barley was significantly higher than that of low P-efficiency in the rhizosphere soil. There was a deficit in rhizosphere available phosphorus of high P-efficiency wild barley, especially in Pi and Pi+Po treatments. The inorganic phosphorus fractions increased with the increasing Pi treatment, and the concentrations of inorganic phosphorus fractions in soil were sorted as follows: Ca10-P > O-P > Fe-P > Al-P > Ca2-P > Ca8-P. The contents of Ca2-P and Ca8-P for high P-efficiency wild barley showed deficits in rhizosphere soil under each phosphorus source treatment. In addition, enrichment of Al-P and Fe-P was observed in Pi treatment in rhizosphere soil. The concentrations of organic phosphorus fractions in soil were sorted as follows: moderate labile organic phosphorus > moderate resistant, resistant organic phosphorus > labile organic phosphorus. The labile and moderate labile organic phosphorus enriched in rhizosphere soil and the greatest enrichment appeared in Pi treatment. Furthermore, the concentrations of moderate resistant organic phosphorus and resistant

  13. Benefits of high aerodynamic efficiency to orbital transfer vehicles

    Science.gov (United States)

    Andrews, D. G.; Norris, R. B.; Paris, S. W.

    1984-01-01

    The benefits and costs of high aerodynamic efficiency on aeroassisted orbital transfer vehicles (AOTV) are analyzed. Results show that a high lift to drag (L/D) AOTV can achieve significant velocity savings relative to low L/D aerobraked OTV's when traveling round trip between low Earth orbits (LEO) and alternate orbits as high as geosynchronous Earth orbit (GEO). Trajectory analysis is used to show the impact of thermal protection system technology and the importance of lift loading coefficient on vehicle performance. The possible improvements in AOTV subsystem technologies are assessed and their impact on vehicle inert weight and performance noted. Finally, the performance of high L/D AOTV concepts is compared with the performances of low L/D aeroassisted and all propulsive OTV concepts to assess the benefits of aerodynamic efficiency on this class of vehicle.

  14. High efficiency inductive output tubes with intense annular electron beams

    Science.gov (United States)

    Appanam Karakkad, J.; Matthew, D.; Ray, R.; Beaudoin, B. L.; Narayan, A.; Nusinovich, G. S.; Ting, A.; Antonsen, T. M.

    2017-10-01

    For mobile ionospheric heaters, it is necessary to develop highly efficient RF sources capable of delivering radiation in the frequency range from 3 to 10 MHz with an average power at a megawatt level. A promising source, which is capable of offering these parameters, is a grid-less version of the inductive output tube (IOT), also known as a klystrode. In this paper, studies analyzing the efficiency of grid-less IOTs are described. The basic trade-offs needed to reach high efficiency are investigated. In particular, the trade-off between the peak current and the duration of the current micro-pulse is analyzed. A particle in the cell code is used to self-consistently calculate the distribution in axial and transverse momentum and in total electron energy from the cathode to the collector. The efficiency of IOTs with collectors of various configurations is examined. It is shown that the efficiency of IOTs can be in the 90% range even without using depressed collectors.

  15. How high are option values in energy-efficiency investments?

    International Nuclear Information System (INIS)

    Sanstad, A.H.; Blumstein, C.; Stoft, S.E.; California Univ., Berkeley, CA,

    1995-01-01

    High implicit discount rates in consumers' energy-efficiency investments have long been a source of controversy. In several recent papers, Hassett and Metcalf argue that the uncertainty and irreversibility attendant to such investments, and the resulting option value, account for this anomalously high implicit discounting. Using their model and data, we show that, to the contrary, their analysis falls well short of providing an explanation of this pattern. (author)

  16. Highly Efficient PCDTBT:PC71 BM Based Photovoltaic Devices without Thermal Annealing Treatment

    International Nuclear Information System (INIS)

    Yang Shao-Peng; Kong Wei-Guang; Liu Bo-Ya; Fu Guang-Sheng; Zheng Wen-Yao; Li Bao-Min; Liu Xian-Hao

    2011-01-01

    We propose an effective method to fabricate highly efficient organic photovoltaic cells based on poly [N-9 - heptadecanyl-2, 7-carbazole-alt-5,5-(4'7'-di-2-thienyl-2'1'3-b-enzothiadiazole): [6,6]-phenyl C 71 -butyric acid methyl ester (PCDTBT:PC 71 BM). A power conversion efficiency of as high as 5.6% and a fill factor of 53.7% are achieved from the optimized cells. The influence of surface morphology of the active layer on the performance of the cells is also investigated. (cross-disciplinary physics and related areas of science and technology)

  17. Highly efficient electroluminescence from a solution-processable thermally activated delayed fluorescence emitter

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Yoshimasa; Kubo, Shosei; Suzuki, Katsuaki; Kaji, Hironori, E-mail: kaji@scl.kyoto-u.ac.jp [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Shizu, Katsuyuki [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Tanaka, Hiroyuki [Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Adachi, Chihaya [Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Japan Science and Technology Agency (JST), ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan)

    2015-11-02

    We developed a thermally activated delayed fluorescence (TADF) emitter, 2,4,6-tris(4-(9,9-dimethylacridan-10-yl)phenyl)-1,3,5-triazine (3ACR-TRZ), suitable for use in solution-processed organic light-emitting diodes (OLEDs). When doped into 4,4′-bis(carbazol-9-yl)biphenyl (CBP) host at 16 wt. %, 3ACR-TRZ showed a high photoluminescence quantum yield of 98%. Transient photoluminescence decay measurements of the 16 wt. % 3ACR-TRZ:CBP film confirmed that 3ACR-TRZ exhibits efficient TADF with a triplet-to-light conversion efficiency of 96%. This high conversion efficiency makes 3ACR-TRZ attractive as an emitting dopant in OLEDs. Using 3ACR-TRZ as an emitter, we fabricated a solution-processed OLED exhibiting a maximum external quantum efficiency of 18.6%.

  18. Efficiency and Loading Evaluation of High Efficiency Mist Eliminators (HEME) - 12003

    Energy Technology Data Exchange (ETDEWEB)

    Giffin, Paxton K.; Parsons, Michael S.; Waggoner, Charles A. [Institute for Clean Energy Technology, Mississippi State University, 205 Research Blvd Starkville, MS 39759 (United States)

    2012-07-01

    High efficiency mist eliminators (HEME) are filters primarily used to remove moisture and/or liquid aerosols from an air stream. HEME elements are designed to reduce aerosol and particulate load on primary High Efficiency Particulate Air (HEPA) filters and to have a liquid particle removal efficiency of approximately 99.5% for aerosols down to sub-micron size particulates. The investigation presented here evaluates the loading capacity of the element in the absence of a water spray cleaning system. The theory is that without the cleaning system, the HEME element will suffer rapid buildup of solid aerosols, greatly reducing the particle loading capacity. Evaluation consists of challenging the element with a waste surrogate dry aerosol and di-octyl phthalate (DOP) at varying intervals of differential pressure to examine the filtering efficiency of three different element designs at three different media velocities. Also, the elements are challenged with a liquid waste surrogate using Laskin nozzles and large dispersion nozzles. These tests allow the loading capacity of the unit to be determined and the effectiveness of washing down the interior of the elements to be evaluated. (authors)

  19. Heat pumps; Synergy of high efficiency and low carbon electricity

    Energy Technology Data Exchange (ETDEWEB)

    Koike, Akio

    2010-09-15

    Heat pump is attracting wide attention for its high efficiency to utilize inexhaustible and renewable ambient heat in the environment. With its rapid innovation and efficiency improvement, this technology has a huge potential to reduce CO2 emissions by replacing currently widespread fossil fuel combustion systems to meet various heat demands from the residential, commercial and industrial sectors. Barriers to deployment such as low public awareness and a relatively long pay-back period do exist, so it is strongly recommended that each country implement policies to promote heat pumps as a renewable energy option and an effective method to combat global warming.

  20. Development of large area, high efficiency amorphous silicon solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, K.S.; Kim, S.; Kim, D.W. [Yu Kong Taedok Institute of Technology (Korea, Republic of)

    1996-02-01

    The objective of the research is to develop the mass-production technologies of high efficiency amorphous silicon solar cells in order to reduce the costs of solar cells and dissemination of solar cells. Amorphous silicon solar cell is the most promising option of thin film solar cells which are relatively easy to reduce the costs. The final goal of the research is to develop amorphous silicon solar cells having the efficiency of 10%, the ratio of light-induced degradation 15% in the area of 1200 cm{sup 2} and test the cells in the form of 2 Kw grid-connected photovoltaic system. (author) 35 refs., 8 tabs., 67 figs.

  1. Iodine laser of high efficiency and fast repetition rate

    Energy Technology Data Exchange (ETDEWEB)

    Hohla, K; Witte, K J

    1976-07-01

    The scaling laws of an iodine laser of high efficiency and fast repetition rate are reported. The laser is pumped with a new kind of low pressure Hg-UV-lamps which convert 32% of the electrical input in UV-light in the absorption band of the iodine laser and which can be fired up to 100 Hz. Details of a 10 kJ/1 nsec system as dimensions, energy density, repetition rate, flow velocity, gas composition and gas pressure and the overall efficiency are given which is expected to be about 2%.

  2. The problems of high efficient extraction from the isochronous cyclotron

    International Nuclear Information System (INIS)

    Schwabe, J.

    1994-06-01

    The problem of high efficient extraction (η ≥ 50%) from isochronous cyclotrons (with the exception of the stripping method) is not completely solved up to this day. This problem is specifically important, because these cyclotrons are being also applied in the production of medical radioisotopes, labeled pharmaceuticals as well as in neutron therapy (oncology), machine industry, agriculture (plant mutagenesis), etc. The aim of the proposed topic is to solve this problem on the AIC-144 isochronous cyclotron in the INP (Institute of Nuclear Physics). Lately, a beam of 20 MeV deuterons with an efficiency of ca. 15% was extracted from this cyclotron. (author). 25 refs, 14 figs

  3. Highly Flexible and Efficient Solar Steam Generation Device.

    Science.gov (United States)

    Chen, Chaoji; Li, Yiju; Song, Jianwei; Yang, Zhi; Kuang, Yudi; Hitz, Emily; Jia, Chao; Gong, Amy; Jiang, Feng; Zhu, J Y; Yang, Bao; Xie, Jia; Hu, Liangbing

    2017-08-01

    Solar steam generation with subsequent steam recondensation has been regarded as one of the most promising techniques to utilize the abundant solar energy and sea water or other unpurified water through water purification, desalination, and distillation. Although tremendous efforts have been dedicated to developing high-efficiency solar steam generation devices, challenges remain in terms of the relatively low efficiency, complicated fabrications, high cost, and inability to scale up. Here, inspired by the water transpiration behavior of trees, the use of carbon nanotube (CNT)-modified flexible wood membrane (F-Wood/CNTs) is demonstrated as a flexible, portable, recyclable, and efficient solar steam generation device for low-cost and scalable solar steam generation applications. Benefitting from the unique structural merits of the F-Wood/CNTs membrane-a black CNT-coated hair-like surface with excellent light absorbability, wood matrix with low thermal conductivity, hierarchical micro- and nanochannels for water pumping and escaping, solar steam generation device based on the F-Wood/CNTs membrane demonstrates a high efficiency of 81% at 10 kW cm -2 , representing one of the highest values ever-reported. The nature-inspired design concept in this study is straightforward and easily scalable, representing one of the most promising solutions for renewable and portable solar energy generation and other related phase-change applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Deposition and Burial Efficiency of Terrestrial Organic Carbon Exported from Small Mountainous Rivers to the Continental Margin, Southwest of Taiwan

    Science.gov (United States)

    Hsu, F.; Lin, S.; Wang, C.; Huh, C.

    2007-12-01

    Terrestrial organic carbon exported from small mountainous river to the continental margin may play an important role in global carbon cycle and it?|s biogeochemical process. A huge amount of suspended materials from small rivers in southwestern Taiwan (104 million tons per year) could serve as major carbon source to the adjacent ocean. However, little is know concerning fate of this terrigenous organic carbon. The purpose of this study is to calculate flux of terrigenous organic carbon deposited in the continental margin, offshore southwestern Taiwan through investigating spatial variation of organic carbon content, organic carbon isotopic compositions, organic carbon deposition rate and burial efficiency. Results show that organic carbon compositions in sediment are strongly influenced by terrestrial material exported from small rivers in the region, Kaoping River, Tseng-wen River and Er-jan Rver. In addition, a major part of the terrestrial materials exported from the Kaoping River may bypass shelf region and transport directly into the deep sea (South China Sea) through the Kaoping Canyon. Organic carbon isotopic compositions with lighter carbon isotopic values are found near the Kaoping River and Tseng-wen River mouth and rapidly change from heavier to lighter values through shelf to slope. Patches of lighter organic carbon isotopic compositions with high organic carbon content are also found in areas west of Kaoping River mouth, near the Kaoshiung city. Furthermore, terrigenous organic carbons with lighter isotopic values are found in the Kaoping canyon. A total of 0.028 Mt/yr of terrestrial organic carbon was found in the study area, which represented only about 10 percent of all terrestrial organic carbon deposited in the study area. Majority (~90 percent) of the organic carbon exported from the Kaoping River maybe directly transported into the deep sea (South China Sea) and become a major source of organic carbon in the deep sea.

  5. Simple processing of high efficiency silicon solar cells

    International Nuclear Information System (INIS)

    Hamammu, I.M.; Ibrahim, K.

    2006-01-01

    Cost effective photovoltaic devices have been an area research since the development of the first solar cells, as cost is the major factor in their usage. Silicon solar cells have the biggest share in the photovoltaic market, though silicon os not the optimal material for solar cells. This work introduces a simplified approach for high efficiency silicon solar cell processing, by minimizing the processing steps and thereby reducing cost. The suggested procedure might also allow for the usage of lower quality materials compared to the one used today. The main features of the present work fall into: simplifying the diffusion process, edge shunt isolation and using acidic texturing instead of the standard alkaline processing. Solar cells of 17% efficiency have been produced using this procedure. Investigations on the possibility of improving the efficiency and using less quality material are still underway

  6. High efficiency graphene coated copper based thermocells connected in series

    Science.gov (United States)

    Sindhuja, Mani; Indubala, Emayavaramban; Sudha, Venkatachalam; Harinipriya, Seshadri

    2018-04-01

    Conversion of low-grade waste heat into electricity had been studied employing single thermocell or flowcells so far. Graphene coated copper electrodes based thermocells connected in series displayed relatively high efficiency of thermal energy harvesting. The maximum power output of 49.2W/m2 for normalized cross sectional electrode area is obtained at 60ºC of inter electrode temperature difference. The relative carnot efficiency of 20.2% is obtained from the device. The importance of reducing the mass transfer and ion transfer resistance to improve the efficiency of the device is demonstrated. Degradation studies confirmed mild oxidation of copper foil due to corrosion caused by the electrolyte.

  7. High Efficiency Graphene Coated Copper Based Thermocells Connected in Series

    Directory of Open Access Journals (Sweden)

    Mani Sindhuja

    2018-04-01

    Full Text Available Conversion of low-grade waste heat into electricity had been studied employing single thermocell or flowcells so far. Graphene coated copper electrodes based thermocells connected in series displayed relatively high efficiency of thermal energy harvesting. The maximum power output of 49.2 W/m2 for normalized cross sectional electrode area is obtained at 60°C of inter electrode temperature difference. The relative carnot efficiency of 20.2% is obtained from the device. The importance of reducing the mass transfer and ion transfer resistance to improve the efficiency of the device is demonstrated. Degradation studies confirmed mild oxidation of copper foil due to corrosion caused by the electrolyte.

  8. Rigid-beam model of a high-efficiency magnicon

    International Nuclear Information System (INIS)

    Rees, D.E.; Tallerico, P.J.; Humphries, S.J. Jr.

    1993-01-01

    The magnicon is a new type of high-efficiency deflection-modulated amplifier developed at the Institute of Nuclear Physics in Novosibirsk, Russia. The prototype pulsed magnicon achieved an output power of 2.4 MW and an efficiency of 73% at 915 MHz. This paper presents the results of a rigid-beam model for a 700-MHz, 2.5-MW 82%-efficient magnicon. The rigid-beam model allows for characterization of the beam dynamics by tracking only a single electron. The magnicon design presented consists of a drive cavity; passive cavities; a pi-mode, coupled-deflection cavity; and an output cavity. It represents an optimized design. The model is fully self-consistent, and this paper presents the details of the model and calculated performance of a 2.5-MW magnicon

  9. HIGH JET EFFICIENCY AND SIMULATIONS OF BLACK HOLE MAGNETOSPHERES

    International Nuclear Information System (INIS)

    Punsly, Brian

    2011-01-01

    This Letter reports on a growing body of observational evidence that many powerful lobe-dominated (FR II) radio sources likely have jets with high efficiency. This study extends the maximum efficiency line (jet power ∼25 times the thermal luminosity) defined in Fernandes et al. so as to span four decades of jet power. The fact that this line extends over the full span of FR II radio power is a strong indication that this is a fundamental property of jet production that is independent of accretion power. This is a valuable constraint for theorists. For example, the currently popular 'no-net-flux' numerical models of black hole accretion produce jets that are two to three orders of magnitude too weak to be consistent with sources near maximum efficiency.

  10. High efficiency particulate removal with sintered metal filters

    International Nuclear Information System (INIS)

    Kirstein, B.E.; Paplawsky, W.J.; Pence, D.T.; Hedahl, T.G.

    1981-01-01

    Because of their particle removal efficiencies and durability, sintered metal filters have been chosen for high efficiency particulate air (HEPA) filter protection in the off-gas treatment system for the proposed Idaho National Engineering Laboratory Transuranic Waste Treatment Facility. Process evaluation of sintered metal filters indicated a lack of sufficient process design data to ensure trouble-free operation. Subsequence pilot scale testing was performed with flyash as the test particulate. The test results showed that the sintered metal filters can have an efficiency greater than 0.9999999 for the specific test conditions used. Stable pressure drop characteristics were observed in pulsed and reversed flow blowback modes of operation. Over 4900 hours of operation were obtained with operating conditions ranging up to approximately 90 0 C and 24 vol % water vapor in the gas stream

  11. 3rd symposium on high-efficiency boiler technology: potential, performance, shortcomings of natural gas fuelled high-efficiency boilers

    International Nuclear Information System (INIS)

    1993-01-01

    The brochure contains abstracts of the papers presented at the symposium. The potential, performance and marketing problems of natural gas high-efficiency boiler systems are outlined, and new ideas are presented for gas utilities, producers of appliances, fitters, and chimneysweeps. 13 papers are available as separate regards in this database. (HW) [de

  12. Order enables efficient electron-hole separation at an organic heterojunction with a small energy loss

    KAUST Repository

    Menke, S. Matthew

    2018-01-12

    Donor–acceptor organic solar cells often show low open-circuit voltages (VOC) relative to their optical energy gap (Eg) that limit power conversion efficiencies to ~12%. This energy loss is partly attributed to the offset between Eg and that of intermolecular charge transfer (CT) states at the donor–acceptor interface. Here we study charge generation occurring in PIPCP:PC61BM, a system with a very low driving energy for initial charge separation (Eg−ECT ~ 50 meV) and a high internal quantum efficiency (ηIQE ~ 80%). We track the strength of the electric field generated between the separating electron-hole pair by following the transient electroabsorption optical response, and find that while localised CT states are formed rapidly (<100 fs) after photoexcitation, free charges are not generated until 5 ps after photogeneration. In PIPCP:PC61BM, electronic disorder is low (Urbach energy <27 meV) and we consider that free charge separation is able to outcompete trap-assisted non-radiative recombination of the CT state.

  13. Metal-inorganic-organic matrices as efficient sorbents for hydrogen storage.

    Science.gov (United States)

    Azzouz, Abdelkrim; Nousir, Saadia; Bouazizi, Nabil; Roy, René

    2015-03-01

    Stabilization of metal nanoparticles (MNPs) without re-aggregation is a major challenge. An unprecedented strategy is developed for achieving high dispersion of copper(0) or palladium(0) on montmorillonite-supported diethanolamine or thioglycerol. This results in novel metal-inorganic-organic matrices (MIOM) that readily capture hydrogen at ambient conditions, with easy release under air stream. Hydrogen retention appears to involve mainly physical interactions, slightly stronger on thioglycerol-based MIOM (S-MIOM). Thermal enhancement of desorption suggests also a contribution of chemical interactions. The increase of hydrogen uptake with prolonged contact times arises from diffusion hindrance, which appears to be beneficial by favoring hydrogen entrapment. Even with compact structures, MIOMs act as efficient sorbents with much higher efficiency factor (1.14-1.17 mmol H 2 m(-2)) than many other sophisticated adsorbents reported in the literature. This opens new prospects for hydrogen storage and potential applications in microfluidic hydrogenation reactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Order enables efficient electron-hole separation at an organic heterojunction with a small energy loss

    KAUST Repository

    Menke, S. Matthew; Cheminal, Alexandre; Conaghan, Patrick; Ran, Niva A.; Greehnam, Neil C.; Bazan, Guillermo C.; Nguyen, Thuc-Quyen; Rao, Akshay; Friend, Richard H.

    2018-01-01

    Donor–acceptor organic solar cells often show low open-circuit voltages (VOC) relative to their optical energy gap (Eg) that limit power conversion efficiencies to ~12%. This energy loss is partly attributed to the offset between Eg and that of intermolecular charge transfer (CT) states at the donor–acceptor interface. Here we study charge generation occurring in PIPCP:PC61BM, a system with a very low driving energy for initial charge separation (Eg−ECT ~ 50 meV) and a high internal quantum efficiency (ηIQE ~ 80%). We track the strength of the electric field generated between the separating electron-hole pair by following the transient electroabsorption optical response, and find that while localised CT states are formed rapidly (<100 fs) after photoexcitation, free charges are not generated until 5 ps after photogeneration. In PIPCP:PC61BM, electronic disorder is low (Urbach energy <27 meV) and we consider that free charge separation is able to outcompete trap-assisted non-radiative recombination of the CT state.

  15. Contact engineering for efficient charge injection in organic transistors with low-cost metal electrodes

    Science.gov (United States)

    Panigrahi, D.; Kumar, S.; Dhar, A.

    2017-10-01

    Controlling charge injection at the metal-semiconductor interface is very crucial for organic electronic devices in general as it can significantly influence the overall device performance. Herein, we report a facile, yet efficient contact modification approach, to enhance the hole injection efficiency through the incorporation of a high vacuum deposited TPD [N,N'-Bis(3-methylphenyl)-N,N'-diphenylbenzidine] interlayer between the electrodes and the active semiconducting layer. The device performance parameters such as mobility and on/off ratio improved significantly after the inclusion of the TPD buffer layer, and more interestingly, the devices with cost effective Ag and Cu electrodes were able to exhibit a superior device performance than the typically used Au source-drain devices. We have also observed that this contact modification technique can be even more effective than commonly used metal oxide interface modifying layers. Our investigations demonstrate the efficacy of the TPD interlayer in effectively reducing the interfacial contact resistance through the modification of pentacene energy levels, which consequently results in the substantial improvement in the device performances.

  16. Lightweight High Efficiency Electric Motors for Space Applications

    Science.gov (United States)

    Robertson, Glen A.; Tyler, Tony R.; Piper, P. J.

    2011-01-01

    Lightweight high efficiency electric motors are needed across a wide range of space applications from - thrust vector actuator control for launch and flight applications to - general vehicle, base camp habitat and experiment control for various mechanisms to - robotics for various stationary and mobile space exploration missions. QM Power?s Parallel Path Magnetic Technology Motors have slowly proven themselves to be a leading motor technology in this area; winning a NASA Phase II for "Lightweight High Efficiency Electric Motors and Actuators for Low Temperature Mobility and Robotics Applications" a US Army Phase II SBIR for "Improved Robot Actuator Motors for Medical Applications", an NSF Phase II SBIR for "Novel Low-Cost Electric Motors for Variable Speed Applications" and a DOE SBIR Phase I for "High Efficiency Commercial Refrigeration Motors" Parallel Path Magnetic Technology obtains the benefits of using permanent magnets while minimizing the historical trade-offs/limitations found in conventional permanent magnet designs. The resulting devices are smaller, lower weight, lower cost and have higher efficiency than competitive permanent magnet and non-permanent magnet designs. QM Power?s motors have been extensively tested and successfully validated by multiple commercial and aerospace customers and partners as Boeing Research and Technology. Prototypes have been made between 0.1 and 10 HP. They are also in the process of scaling motors to over 100kW with their development partners. In this paper, Parallel Path Magnetic Technology Motors will be discussed; specifically addressing their higher efficiency, higher power density, lighter weight, smaller physical size, higher low end torque, wider power zone, cooler temperatures, and greater reliability with lower cost and significant environment benefit for the same peak output power compared to typically motors. A further discussion on the inherent redundancy of these motors for space applications will be provided.

  17. Test Program for High Efficiency Gas Turbine Exhaust Diffuser

    Energy Technology Data Exchange (ETDEWEB)

    Norris, Thomas R.

    2009-12-31

    This research relates to improving the efficiency of flow in a turbine exhaust, and thus, that of the turbine and power plant. The Phase I SBIR project demonstrated the technical viability of “strutlets” to control stalls on a model diffuser strut. Strutlets are a novel flow-improving vane concept intended to improve the efficiency of flow in turbine exhausts. Strutlets can help reduce turbine back pressure, and incrementally improve turbine efficiency, increase power, and reduce greenhouse gas emmission. The long-term goal is a 0.5 percent improvement of each item, averaged over the US gas turbine fleet. The strutlets were tested in a physical scale model of a gas turbine exhaust diffuser. The test flow passage is a straight, annular diffuser with three sets of struts. At the end of Phase 1, the ability of strutlets to keep flow attached to struts was demonstrated, but the strutlet drag was too high for a net efficiency advantage. An independently sponsored followup project did develop a highly-modified low-drag strutlet. In combination with other flow improving vanes, complicance to the stated goals was demonstrated for for simple cycle power plants, and to most of the goals for combined cycle power plants using this particular exhaust geometry. Importantly, low frequency diffuser noise was reduced by 5 dB or more, compared to the baseline. Appolicability to other diffuser geometries is yet to be demonstrated.

  18. Efficient Smoothed Concomitant Lasso Estimation for High Dimensional Regression

    Science.gov (United States)

    Ndiaye, Eugene; Fercoq, Olivier; Gramfort, Alexandre; Leclère, Vincent; Salmon, Joseph

    2017-10-01

    In high dimensional settings, sparse structures are crucial for efficiency, both in term of memory, computation and performance. It is customary to consider ℓ 1 penalty to enforce sparsity in such scenarios. Sparsity enforcing methods, the Lasso being a canonical example, are popular candidates to address high dimension. For efficiency, they rely on tuning a parameter trading data fitting versus sparsity. For the Lasso theory to hold this tuning parameter should be proportional to the noise level, yet the latter is often unknown in practice. A possible remedy is to jointly optimize over the regression parameter as well as over the noise level. This has been considered under several names in the literature: Scaled-Lasso, Square-root Lasso, Concomitant Lasso estimation for instance, and could be of interest for uncertainty quantification. In this work, after illustrating numerical difficulties for the Concomitant Lasso formulation, we propose a modification we coined Smoothed Concomitant Lasso, aimed at increasing numerical stability. We propose an efficient and accurate solver leading to a computational cost no more expensive than the one for the Lasso. We leverage on standard ingredients behind the success of fast Lasso solvers: a coordinate descent algorithm, combined with safe screening rules to achieve speed efficiency, by eliminating early irrelevant features.

  19. High Efficiency, High Temperature Foam Core Heat Exchanger for Fission Surface Power Systems, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Fission-based power systems with power levels of 30 to ≥100 kWe will be needed for planetary surface bases. Development of high temperature, high efficiency heat...

  20. Combustion phasing for maximum efficiency for conventional and high efficiency engines

    International Nuclear Information System (INIS)

    Caton, Jerald A.

    2014-01-01

    Highlights: • Combustion phasing for max efficiency is a function of engine parameters. • Combustion phasing is most affected by heat transfer, compression ratio, burn duration. • Combustion phasing is less affected by speed, load, equivalence ratio and EGR. • Combustion phasing for a high efficiency engine was more advanced. • Exergy destruction during combustion as functions of combustion phasing is reported. - Abstract: The importance of the phasing of the combustion event for internal-combustion engines is well appreciated, but quantitative details are sparse. The objective of the current work was to examine the optimum combustion phasing (based on maximum bmep) as functions of engine design and operating variables. A thermodynamic, engine cycle simulation was used to complete this assessment. As metrics for the combustion phasing, both the crank angle for 50% fuel mass burned (CA 50 ) and the crank angle for peak pressure (CA pp ) are reported as functions of the engine variables. In contrast to common statements in the literature, the optimum CA 50 and CA pp vary depending on the design and operating variables. Optimum, as used in this paper, refers to the combustion timing that provides the maximum bmep and brake thermal efficiency (MBT timing). For this work, the variables with the greatest influence on the optimum CA 50 and CA pp were the heat transfer level, the burn duration and the compression ratio. Other variables such as equivalence ratio, EGR level, engine speed and engine load had a much smaller impact on the optimum CA 50 and CA pp . For the conventional engine, for the conditions examined, the optimum CA 50 varied between about 5 and 11°aTDC, and the optimum CA pp varied between about 9 and 16°aTDC. For a high efficiency engine (high dilution, high compression ratio), the optimum CA 50 was 2.5°aTDC, and the optimum CA pp was 7.8°aTDC. These more advanced values for the optimum CA 50 and CA pp for the high efficiency engine were