WorldWideScience

Sample records for plastic flexible substrates

  1. Flexible and tunable silicon photonic circuits on plastic substrates

    CERN Document Server

    Chen, Yu; Li, Mo

    2012-01-01

    Flexible microelectronics has shown tremendous promise in a broad spectrum of applications, especially those that cannot be addressed by conventional microelectronics in rigid materials and constructions1-3. These unconventional yet important applications range from flexible consumer electronics to conformal sensor arrays and biomedical devices. A recent successful paradigm shift in implementing flexible electronics is to physically transfer and bond highly integrated devices made in high-quality, crystalline semiconductor materials on to plastic materials4-8. Here we demonstrate a flexible form of silicon photonics on plastic substrates using the transfer-and-bond fabrication method. Photonic circuits including interferometers and resonators have been transferred onto flexible plastic substrates with preserved functionalities and performance. By mechanically deforming the flexible substrates, the optical characteristics of the devices can be tuned reversibly over a remarkably large range. The demonstration o...

  2. Improved Barrier Properties in Flexible Plastic Substrates

    Science.gov (United States)

    2009-01-01

    high surface roughness of commercially available plastic substrates such as polyethylene terephthalate ( PET ), polycarbonate (PC) and cyclic olefin...PolyTetraFlouro Ethylene (PTFE), PolyEthylene Terephthalate ( PET ) and PolyEthylene Naphthalate(PEN), the permeation rates are typically >1x103g/m2day for...oxygen and >1g/m2day for water depending on the thickness of the polymer.10 WVTR for a 25nm thick PEN and PET is 6.7 g/m2day11 and 21.3 g/m2day11 and

  3. Optically transparent frequency selective surfaces on flexible thin plastic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Dewani, Aliya A., E-mail: a.ashraf@griffith.edu.au; O’Keefe, Steven G.; Thiel, David V.; Galehdar, Amir [School Of Electrical Engineering, Griffith University, Brisbane, 4111 (Australia)

    2015-02-15

    A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing) to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers.

  4. Optically transparent frequency selective surfaces on flexible thin plastic substrates

    Science.gov (United States)

    Dewani, Aliya A.; O'Keefe, Steven G.; Thiel, David V.; Galehdar, Amir

    2015-02-01

    A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing) to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers.

  5. Optically transparent frequency selective surfaces on flexible thin plastic substrates

    Directory of Open Access Journals (Sweden)

    Aliya A. Dewani

    2015-02-01

    Full Text Available A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm, flexible transparent plastic substrate (relative permittivity 3.2. It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers.

  6. New hybrid encapsulation for flexible organic light-emitting devices on plastic substrates

    Institute of Scientific and Technical Information of China (English)

    LIU Song; ZHANG DeQiang; LI Yang; DUAN Lian; DONG GuiFang; WANG LiDuo; QIU Yong

    2008-01-01

    The hybrid encapsulation for flexible organic light-emitting devices on plastic substrate was investi-gated. The hybrid encapsulation consisted of four periods of Alq3/LiF layers as the pre-encapsulation layer and a flexible aluminum foil coated with getter as the encapsulation cap. We measured the device lifetime at a continuous constant current of 20 mA/cm2, which corresponded to an initial luminance of 2000 cd/m2, The half-luminance decay time of the encapsulated device was about 458 h. More over, the hybrid encapsulation is ultrathin and flexible, ensuring device bendability.

  7. A simple enzyme based biosensor on flexible plastic substrate

    Science.gov (United States)

    Kanakamedala, Senaka K.; Alshakhouri, Haidar T.; Agarwal, Mangilal; Fang, Ji; DeCoster, Mark A.

    2010-08-01

    An enzyme based biosensor was fabricated by employing a simple, inexpensive and rapid xurography fabrication process. The electrodes and channel were made from the conducting polymer poly(3,4-ethyelenedioxythiphene) poly(styrene sulfonate) (PEDOT:PSS). PEDOT:PSS was selectively deposited using a polyimide tape mask. The tape mask was peeled off from the substrate after annealing the polymer in vacuum. Polymer wells of defined dimensions were made and were attached to the device to accommodate the solutions. This sensor utilizes the change in current as a parameter to measure different analyte concentrations. Initial experiments were done by using the sensor for glucose detection. The sensor is able to detect the glucose concentrations approximately from 1 μM to 10 mM range covering glucose in human saliva (8-210 μM). The glucose oxidase activity was independently measured using colorimetric method and the results indicate that the sensor retains the enzyme activity and can be used as a biosensor to detect various analytes. The analyte of interest can be measured by preloading the corresponding enzyme into the wells.

  8. Polymer-stabilized ferroelectric liquid crystal for flexible displays using plastic substrates

    Science.gov (United States)

    Fujikake, Hideo; Murashige, Takeshi; Sato, Hiroto; Iino, Yoshiki; Kikuchi, Hiroshi; Kawakita, Masahiro; Tsuchiya, Yuzuru

    2001-12-01

    We have developed a ferroelectric liquid crystal device with a novel structure containing a polymer fiber network for flexible lightweight displays using thin plastic substrates. The aligned polymer fibers of sub-micrometers -diameter were formed under ultraviolet light irradiation in a heated nematic- phase solution consisting of liquid crystal and monofunctional acrylate monomer. The rigid polymer network was found to adhere to the two plastic substrates, and the uniform liquid crystal alignment provided a contrast ratio of 100:1 for a monomer concentration of 20 wt%. This device achieves a continuous grayscale capability as a result of change in the spatial distribution of small liquid crystal domains, and also exhibits a fast response time of 80 microsecond(s) due to high-purity separation of polymer and liquid crystal materials. It therefore has attractive features for flexible moving-image display applications.

  9. Flexible photodetectors on plastic substrates by use of printing transferred single-crystal germanium membranes

    Science.gov (United States)

    Yuan, Hao-Chih; Shin, Jonghyun; Qin, Guoxuan; Sun, Lei; Bhattacharya, Pallab; Lagally, Max G.; Celler, George K.; Ma, Zhenqiang

    2009-01-01

    This letter presents studies of multiwavelength flexible photodetectors on a plastic substrate by use of printing transferred single-crystal germanium (Ge) membranes. Ge membranes of 250nm thickness with selectively ion-implantation doped regions were released from a germanium-on-insulator substrate and integrated with a 175-μm-thick polyethylene terephthalate substrate via a dry printing technique. Photodiodes configured in lateral p-i-n configuration using the flexible Ge membranes with an intrinsic region width of 10μm exhibit an external quantum efficiency that varies from 5% at 411nm to 42% at 633nm under -1V bias condition. These results demonstrate the potential of utilizing single-crystal Ge-membrane photodiodes for imaging applications and as solar cells on objects with arbitrary curvatures and shapes.

  10. Micro and nanopatterning of functional materials on flexible plastic substrates via site-selective surface modification using oxygen plasma

    NARCIS (Netherlands)

    George, A.; Stawski, T.M.; Unnikrishnan, S.; Veldhuis, S.A.; Elshof, J.E. ten

    2012-01-01

    A simple and cost effective methodology for large area micro and nanopatterning of a wide range of functional materials on flexible substrates is presented. A hydrophobic-hydrophilic chemical contrast was patterned on surfaces of various flexible plastic substrates using molds and shadow masks with

  11. Micro and nanopatterning of functional materials on flexible plastic substrates via site-selective surface modification using oxygen plasma

    NARCIS (Netherlands)

    George, A.; Stawski, T.M.; Unnikrishnan, S.; Veldhuis, S.A.; Elshof, J.E. ten

    2012-01-01

    A simple and cost effective methodology for large area micro and nanopatterning of a wide range of functional materials on flexible substrates is presented. A hydrophobic-hydrophilic chemical contrast was patterned on surfaces of various flexible plastic substrates using molds and shadow masks with

  12. Micro- and nanopatterning of functional materials on flexible plastic substrates via site-selective surface modification using oxygen plasma

    NARCIS (Netherlands)

    George, A.; Stawski, T.M.; Unnikrishnan, S.; Veldhuis, S.A.; Elshof, ten J.E.

    2012-01-01

    A simple and cost effective methodology for large area micro and nanopatterning of a wide range of functional materials on flexible substrates is presented. A hydrophobic-hydrophilic chemical contrast was patterned on surfaces of various flexible plastic substrates using molds and shadow masks with

  13. Fundamental display properties of flexible devices containing polymer-stabilized ferroelectric liquid crystal between plastic substrates

    Science.gov (United States)

    Fujikake, Hideo; Murashige, Takeshi; Sato, Hiroto; Iino, Yoshiki; Kawakita, Masahiro; Kikuchi, Hiroshi

    2002-09-01

    We describe several fundamental display properties of a flexible ferroelectric liquid crystal device containing polymer fibers between thin plastic substrates. The composite film of liquid crystal and polymer was created from a solution of liquid crystal and monomer materials between the plastic substrates under ultraviolet light irradiation. The dynamic electrooptic response to analog voltage pulses was examined with an incidence of laser beam light, and its light modulation property exhibited good linearity in continuous gray-scale capability. The excellent spatial uniformity of liquid crystal alignment formed between the flexible substrates resulted in high-contrast light modulation, although slight spontaneous bending of liquid crystal alignment in the device plane was recognized. When the laser light beam was obliquely incident on the flexible display device, the measured transmittance revealed that the device has a wide viewing angle of more than 100 deg without contrast reversal. This is considered to be caused by the molecular switching in the device plane and the thin electrooptic layer in the display device.

  14. Flexible aluminum-doped zinc-oxide thin-film transistor fabricated on plastic substrates

    Science.gov (United States)

    Han, Dedong; Chen, Zhuofa; Zhao, Nannan; Wang, Wei; Huang, Fuqing; Zhang, Shengdong; Zhang, Xing; Wang, Yi

    2014-03-01

    We have studied processing and characteristics of flexible Aluminum-doped Zinc Oxide thin-film transistors (AZO TFTs) fabricated on plastic substrates using radio frequency (rf) magnetron sputtering. To improve the performance of flexible AZO TFT, we studied effects of device structures on characteristics of the aluminum-doped zinc oxide thin film transistors. The electrical properties of top-gate type and bottom-gate type AZO TFTs were investigated, respectively. The top-gate type AZO TFTs shows a threshold voltage of 1.4 V, a Ion/Ioff current ratio of 1.0×107, a field effect mobility of 28.2 cm2/ V•s, a subthreshold swing of 0.19 V/decade. And the bottom-gate type AZO TFTs shows a threshold voltage of 1.7 V, a Ion/Ioff ratio of 1.0×107, a field effect mobility of 209 cm2/ V•s, a subthreshold swing of 0.16 V/decade, and the off current of less than 10-11A at room temperature. Both TFTs show low threshold voltage, high Ion/Ioff ratio and high field effect mobility. By comparison, the bottom-gate type AZO TFTs shows better characteristics. The flexible AZO-TFT is a very promising low-cost optoelectronic device for the next generation of invisible and flexible electronics due to flexible, transparency, high mobility, and low-temperature processing.

  15. Fully transparent flexible tin-doped zinc oxide thin film transistors fabricated on plastic substrate

    Science.gov (United States)

    Han, Dedong; Zhang, Yi; Cong, Yingying; Yu, Wen; Zhang, Xing; Wang, Yi

    2016-12-01

    In this work, we have successfully fabricated bottom gate fully transparent tin-doped zinc oxide thin film transistors (TZO TFTs) fabricated on flexible plastic substrate at low temperature by RF magnetron sputtering. The effect of O2/Ar gas flow ratio during channel deposition on the electrical properties of TZO TFTs was investigated, and we found that the O2/Ar gas flow ratio have a great influence on the electrical properties. TZO TFTs on flexible substrate has very nice electrical characteristics with a low off-state current (Ioff) of 3 pA, a high on/off current ratio of 2 × 107, a high saturation mobility (μsat) of 66.7 cm2/V•s, a steep subthreshold slope (SS) of 333 mV/decade and a threshold voltage (Vth) of 1.2 V. Root-Mean-Square (RMS) roughness of TZO thin film is about 0.52 nm. The transmittance of TZO thin film is about 98%. These results highlight that the excellent device performance can be realized in TZO film and TZO TFT can be a promising candidate for flexible displays.

  16. Completely transparent conducting oxide-free and flexible dye-sensitized solar cells fabricated on plastic substrates.

    Science.gov (United States)

    Yoo, Kicheon; Kim, Jae-Yup; Lee, Jin Ah; Kim, Jin Soo; Lee, Doh-Kwon; Kim, Kyungkon; Kim, Jin Young; Kim, BongSoo; Kim, Honggon; Kim, Won Mok; Kim, Jong Hak; Ko, Min Jae

    2015-04-28

    To achieve commercialization and widespread application of next-generation photovoltaics, it is important to develop flexible and cost-effective devices. Given this, the elimination of expensive transparent conducting oxides (TCO) and replacement of conventional glass substrates with flexible plastic substrates presents a viable strategy to realize extremely low-cost photovoltaics with a potentially wide applicability. To this end, we report a completely TCO-free and flexible dye-sensitized solar cell (DSSC) fabricated on a plastic substrate using a unique transfer method and back-contact architecture. By adopting unique transfer techniques, the working and counter electrodes were fabricated by transferring high-temperature-annealed TiO2 and Pt/carbon films, respectively, onto flexible plastic substrates without any exfoliation. The fabricated working electrode with the conventional counter electrode exhibited a record efficiency for flexible DSSCs of 8.10%, despite its TCO-free structure. In addition, the completely TCO-free and flexible DSSC exhibited a remarkable efficiency of 7.27%. Furthermore, by using an organic hole-transporting material (spiro-MeOTAD) with the same transfer method, solid-state flexible TCO-free DSSCs were also successfully fabricated, yielding a promising efficiency of 3.36%.

  17. Roll-to-Roll Encapsulation of Metal Nanowires between Graphene and Plastic Substrate for High-Performance Flexible Transparent Electrodes.

    Science.gov (United States)

    Deng, Bing; Hsu, Po-Chun; Chen, Guanchu; Chandrashekar, B N; Liao, Lei; Ayitimuda, Zhawulie; Wu, Jinxiong; Guo, Yunfan; Lin, Li; Zhou, Yu; Aisijiang, Mahaya; Xie, Qin; Cui, Yi; Liu, Zhongfan; Peng, Hailin

    2015-06-10

    Transparent conductive film on plastic substrate is a critical component in low-cost, flexible, and lightweight optoelectronics. Industrial-scale manufacturing of high-performance transparent conductive flexible plastic is needed to enable wide-ranging applications. Here, we demonstrate a continuous roll-to-roll (R2R) production of transparent conductive flexible plastic based on a metal nanowire network fully encapsulated between graphene monolayer and plastic substrate. Large-area graphene film grown on Cu foil via a R2R chemical vapor deposition process was hot-laminated onto nanowires precoated EVA/PET film, followed by a R2R electrochemical delamination that preserves the Cu foil for reuse. The encapsulated structure minimized the resistance of both wire-to-wire junctions and graphene grain boundaries and strengthened adhesion of nanowires and graphene to plastic substrate, resulting in superior optoelectronic properties (sheet resistance of ∼8 Ω sq(-1) at 94% transmittance), remarkable corrosion resistance, and excellent mechanical flexibility. With these advantages, long-cycle life flexible electrochromic devices are demonstrated, showing up to 10000 cycles.

  18. Flexibility of the Indium Tin Oxide Transparent Conductive Film Deposited Onto the Plastic Substrate

    Directory of Open Access Journals (Sweden)

    Shao-Kai Lu

    2014-03-01

    Full Text Available In this study, we utilize the RF magnetron sputtering system to deposit the indium tin oxide (ITO conductive transparent film with low resistivity and high light transmittance to the polyethylene tetephthalate (PET plastic substrate and measure the film’s bending property and reliability at different tensile/compressive strain bending curvatures as well as the flexibility after cycling bending. The results show that the critical curvatures corresponded to the significant increase in the resistance of the 150 nm-thick ITO film deposited onto the PET substrate under tensile and compressive stress areO 14.1 mm and 5.4 mm, respectively. By observing the film’s surface crack and morphology, we can further discover that the critical curvature of the crack generated when the film is bent is quite consistent with the critical curvature at which the conductivity property degrades, and the film can withstand a higher compressive strain bending. In addition, the resistance and adhesion behavior of the film almost is unchanged after cycling bent for 1000 times with the curvature below the critical curvature.

  19. Hygroscopic and thermal micro deformations of plastic substrates for flexible electronics using digital image correlation

    NARCIS (Netherlands)

    Berg, D. van den; Barink, M.; Giesen, P.; Meinders, E.R.; Yakimets, I.

    2010-01-01

    Thin polymer substrates are promising materials for flexible electronics with many advantages. However, the dimensional stability of polymer substrates is low. Nowadays, this is overcome by laminating polymer substrates onto a rigid carrier. Nevertheless, carrier-less processing will be a foreseen n

  20. Hygroscopic and thermal micro deformations of plastic substrates for flexible electronics using digital image correlation

    NARCIS (Netherlands)

    Berg, D. van den; Barink, M.; Giesen, P.; Meinders, E.R.; Yakimets, I.

    2011-01-01

    Thin polymer substrates are promising materials for flexible electronics with many advantages. However, the dimensional stability of polymer substrates is low. Nowadays, this is overcome by laminating polymer substrates onto a rigid carrier. Nevertheless, carrier-less processing will be a foreseen n

  1. Photolithographic Synthesis of High-Density DNA and RNA Arrays on Flexible, Transparent, and Easily Subdivided Plastic Substrates.

    Science.gov (United States)

    Holden, Matthew T; Carter, Matthew C D; Wu, Cheng-Hsien; Wolfer, Jamison; Codner, Eric; Sussman, Michael R; Lynn, David M; Smith, Lloyd M

    2015-11-17

    The photolithographic fabrication of high-density DNA and RNA arrays on flexible and transparent plastic substrates is reported. The substrates are thin sheets of poly(ethylene terephthalate) (PET) coated with cross-linked polymer multilayers that present hydroxyl groups suitable for conventional phosphoramidite-based nucleic acid synthesis. We demonstrate that by modifying array synthesis procedures to accommodate the physical and chemical properties of these materials, it is possible to synthesize plastic-backed oligonucleotide arrays with feature sizes as small as 14 μm × 14 μm and feature densities in excess of 125 000/cm(2), similar to specifications attainable using rigid substrates such as glass or glassy carbon. These plastic-backed arrays are tolerant to a wide range of hybridization temperatures, and improved synthetic procedures are described that enable the fabrication of arrays with sequences up to 50 nucleotides in length. These arrays hybridize with S/N ratios comparable to those fabricated on otherwise identical arrays prepared on glass or glassy carbon. This platform supports the enzymatic synthesis of RNA arrays and proof-of-concept experiments are presented showing that the arrays can be readily subdivided into smaller arrays (or "millichips") using common laboratory-scale laser cutting tools. These results expand the utility of oligonucleotide arrays fabricated on plastic substrates and open the door to new applications for these important bioanalytical tools.

  2. Self-assembled nanodielectrics and silicon nanomembranes for low voltage, flexible transistors, and logic gates on plastic substrates

    Science.gov (United States)

    Kim, Hoon-Sik; Won, Sang Min; Ha, Young-Geun; Ahn, Jong-Hyun; Facchetti, Antonio; Marks, Tobin J.; Rogers, John A.

    2009-11-01

    This letter reports the fabrication and electrical characterization of mechanically flexible and low operating voltage transistors and logic gates (NOT, NAND, and NOR gates) using printed silicon nanomembranes and self-assembled nanodielectrics on thin plastic substrates. The transistors exhibit effective linear mobilities of ˜680 cm2/V s, on/off ratios >107, gate leakage current densities <2.8×10-7 A/cm2, and subthreshold slopes ˜120 mV/decade. The inverters show voltage gains as high as 4.8. Simple digital logic gates (NAND and NOR gates) demonstrate the possible application of this materials combination in digital integrated circuits.

  3. Flexible nickel-doped zinc oxide thin-film transistors fabricated on plastic substrates at low temperature

    Science.gov (United States)

    Huang, Lingling; Han, Dedong; Chen, Zhuofa; Cong, Yingying; Wu, Jing; Zhao, Nannan; Dong, Junchen; Zhao, Feilong; Liu, Lifeng; Zhang, Shengdong; Zhang, Xing; Wang, Yi

    2015-04-01

    High-performance nickel (Ni)-doped zinc oxide thin-film transistors (NZO TFTs) have been successfully fabricated on transparent flexible plastic substrates at a low temperature. The effect of different oxygen partial pressures during channel deposition on the electrical properties of NZO TFTs was studied to improve the device performance. We found that the oxygen partial pressure during channel deposition has a significant influence on the performance of NZO TFTs. Finally, it was demonstrated that a NZO film with 100% Ar sputtering gas during channel deposition exhibited the best electrical properties, with a drain current on/off ratio of 108, a positive threshold voltage of 2.59 V, a subthreshold swing of 233 mV/decade, and a saturation mobility of 118.9 cm2·V-1·s-1. The results show that Ni-doped ZnO is a promising candidate for flexible fully transparent displays.

  4. Inkjet-printed dissolved oxygen and pH sensors on flexible plastic substrates

    Science.gov (United States)

    Moya, A.; Zea, M.; Sowade, E.; Villa, R.; Ramon, E.; Baumann, R. R.; Gabriel, G.

    2017-06-01

    There are a broad range of applications such as analytical sensors, biosensing and medical applications that require the monitoring of dissolved oxygen (DO) and pH using sensitive, stable, compact and low cost sensors. Here we develop full inkjet printing sensors to measure DO and pH. They have been fabricated using commercially available gold and platinum inks in plastic substrates. The inks are specially designed formulation which allows their sintering at temperatures as low as 150 and 190 °C for Au and Pt respectively. This is a key point in the development of low-cost sensors made on plastic and paper substrates. These sensors integrate in a single platform all the basic elements for pH and DO recording, allowing the measures without any external electrode. The DO is directly measured with a gold working electrode, and the pH sensors is achieved after electrodepositing iridium oxide film over platinum working electrode. The printed electrodes for DO sensing exhibits excellent linearity between 0 and 8 mg L _ 1 range, with correlation factors greater than 0.99, obtaining low limits of detection, 0.17 mgL _ 1 and a sensitivity of 0.06 A(mgL) _ 1. IrOx pH sensors exhibit a super-Nernstian response in sensitivity repeatedly and reversibly between 65 mV/pH in the pH range of 3 to 10. This work demonstrates that these sensors are suitable for the determination of DO and pH and provide a cost-effective solution for future electrochemical monitoring systems.

  5. Advances in maskless and mask-based optical lithography on plastic flexible substrates

    NARCIS (Netherlands)

    Barbu, I.; Ivan, M.G.; Giesen, P.; Moosdijk, M. van de; Meinders, E.R.

    2009-01-01

    Organic flexible electronics is an emerging technology with huge potential growth in the future which is likely to open up a complete new series of potential applications such as flexible OLED-based displays, urban commercial signage, and flexible electronic paper. The transistor is the fundamental

  6. Highly-efficient, flexible piezoelectric PZT thin film nanogenerator on plastic substrates.

    Science.gov (United States)

    Park, Kwi-Il; Son, Jung Hwan; Hwang, Geon-Tae; Jeong, Chang Kyu; Ryu, Jungho; Koo, Min; Choi, Insung; Lee, Seung Hyun; Byun, Myunghwan; Wang, Zhong Lin; Lee, Keon Jae

    2014-04-23

    A highly-efficient, flexible piezoelectric PZT thin film nanogenerator is demonstrated using a laser lift-off (LLO) process. The PZT thin film nanogenerator harvests the highest output performance of ∼200 V and ∼150 μA·cm(-2) from regular bending motions. Furthermore, power sources generated from a PZT thin film nanogenerator, driven by slight human finger bending motions, successfully operate over 100 LEDs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. All-printed carbon nanotube finFETs on plastic substrates for high-performance flexible electronics.

    Science.gov (United States)

    Shi, Jingsheng; Guo, Chun Xian; Chan-Park, Mary B; Li, Chang Ming

    2012-01-17

    The performance of all-printed flexible electronics is still much lower than silicon devices and significantly limits their commercially viable production. All-printed flexible carbon nanotube (CNT) fin field-effect transistors (FETs) with dielectric-wrapped CNT network are demonstrated with remarkable performance, making it possible to mass-produce high-performance, all-printed flexible electronics on large-area substrates. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. High performance printed N and P-type OTFTs enabling digital and analog complementary circuits on flexible plastic substrate

    Science.gov (United States)

    Jacob, S.; Abdinia, S.; Benwadih, M.; Bablet, J.; Chartier, I.; Gwoziecki, R.; Cantatore, E.; van Roermund, A. H. M.; Maddiona, L.; Tramontana, F.; Maiellaro, G.; Mariucci, L.; Rapisarda, M.; Palmisano, G.; Coppard, R.

    2013-06-01

    This paper presents a printed organic complementary technology on flexible plastic substrate with high performance N and P-type Organic Thin Film Transistors (OTFTs), based on small-molecule organic semiconductors in solution. Challenges related to the integration of both OTFT types in a common complementary flow are addressed, showing the importance of surface treatments. Stability on single devices and on an elementary complementary digital circuit (ring oscillator) is studied, demonstrating that a robust and reliable flow with high electrical performances can be established for printed organic devices. These devices are used to manufacture several analog and digital building blocks. The design is carried out using a model specifically developed for this technology, and taking into account the parametric variability. High-frequency measurements of printed envelope detectors show improved speed performance, resulting from the high mobility of the OTFTs. In addition, a compact dynamic flip-flop and a low-offset comparator are demonstrated, thanks to availability of both n-type and p-type OTFTs in the technology. Measurement results are in good agreement with the simulations. The circuits presented establish a complete library of building blocks for the realization of a printed RFID tag.

  9. X-ray imager using solution processed organic transistor arrays and bulk heterojunction photodiodes on thin, flexible plastic substrate

    NARCIS (Netherlands)

    Gelinck, G.H.; Kumar, A.; Moet, D.; Steen, J.L. van der; Shafique, U.; Malinowski, P.E.; Myny, K.; Rand, B.P.; Simon, M.; Rütten, W.; Douglas, A.; Jorritsma, J.; Heremans, P.L.; Andriessen, H.A.J.M.

    2013-01-01

    We describe the fabrication and characterization of large-area active-matrix X-ray/photodetector array of high quality using organic photodiodes and organic transistors. All layers with the exception of the electrodes are solution processed. Because it is processed on a very thin plastic substrate o

  10. Evaluation of the gauge factor for single-walled carbon nanonets on the flexible plastic substrates by nano-transfer-printing

    Science.gov (United States)

    Hsu, C. C.; Chao, R. M.; Liu, C. W.; Liang, Steven Y.

    2011-07-01

    Nano-transfer-printing (nTP) is increasingly used for the micro-fabrication of nanoscale materials onto flexible plastic substrates. This paper reports a nTP process for single-walled carbon nanonets (SWCNNs) for use in strain sensors. Traditional SWCNNs grown on a silicon substrate by alcohol catalytic chemical vapor deposition (ACCVD) can serve as strain-sensing elements in strain sensors and nano-electromechanical system (NEMS) sensors, but ACCVD is not well suited to the task. To improve SWCNN fabrication, this work deposits a parylene-C thin film on SWCNNs for transfer-printing onto flexible plastic substrates with polyimide tape. Quantification of the fabricated SWCNN strain-sensing ability (gauge factor) is performed by comparing two specimens with different pattern features and substrates. The gauge factor is measured by tensile testing. SWCNN density variations relative to the observed gauge factors are discussed. Results show that SWCNN gauge factors range from 1.46 to 8.22, depending on the substrate and pattern width. It is further observed that the gauge factor of the presented SWCNN thin film increases when the width of the SWCNN decreases to the low micro-dimensions, i.e. below 40 µm, indicating a significant scaling factor.

  11. Transparent anodic TiO2 nanotube arrays on plastic substrates for disposable biosensors and flexible electronics.

    Science.gov (United States)

    Farsinezhad, Samira; Mohammadpour, Arash; Dalrymple, Ashley N; Geisinger, Jared; Kar, Piyush; Brett, Michael J; Shankar, Karthik

    2013-04-01

    Exploitation of anodically formed self-organized TiO2 nanotube arrays in mass-manufactured, disposable biosensors, rollable electrochromic displays and flexible large-area solar cells would greatly benefit from integration with transparent and flexible polymeric substrates. Such integration requires the vacuum deposition of a thin film of titanium on the desired substrate, which is then anodized in suitable media to generate TiO2 nanotube arrays. However the challenges associated with control of Ti film morphology, nanotube array synthesis conditions, and film adhesion and transparency, have necessitated the use of substrate heating during deposition to temperatures of at least 300 degrees C and as high as 500 degrees C to generate highly ordered open-pore nanotube arrays, thus preventing the use of polymeric substrates. We report on a film growth technique that exploits atomic peening to achieve high quality transparent TiO2 nanotube arrays with lengths up to 5.1 microm at room temperature on polyimide substrates without the need for substrate heating or substrate biasing or a Kauffman ion source. The superior optical quality and uniformity of the nanotube arrays was evidenced by the high specular reflectivity and the smooth pattern of periodic interferometric fringes in the transmission spectra of the nanotube arrays, from which the wavelength-dependent effective refractive index was extracted for the air-TiO2 composite medium. A fluorescent immunoassay biosensor constructed using 5.1 microm-long transparent titania nanotube arrays (TTNAs) grown on Kapton substrates detected human cardiac troponin I at a concentration of 0.1 microg ml(-1).

  12. Printed highly conductive Cu films with strong adhesion enabled by low-energy photonic sintering on low-Tg flexible plastic substrate

    Science.gov (United States)

    Wu, Xinzhou; Shao, Shuangshuang; Chen, Zheng; Cui, Zheng

    2017-01-01

    Copper (Cu) films and circuits were fabricated by screen-printing Cu nanoink on low-Tg (glass transition temperature) flexible plastic substrates (PEN and PET) instead of widely used high-Tg polyimide (PI) substrate. Photonic sintering of printed Cu films was carried out using intensive pulsed light (IPL). Low resistivities of 28 μΩ · cm on PEN and 44 μΩ · cm on PET were obtained without damaging the substrates. The sintered Cu films exhibited strong adhesion to PEN and PET substrates, with measured adhesion strength of 5B by the ASTM D3359 international standard, whereas the top part of the copper film on the PI substrate was stripped off during the adhesion test. The sintered Cu films also showed excellent stability in harsh conditions and mechanical flexibility in rolling tests. The underlying mechanisms of the high conductivity and strong adhesion on PEN and PET substrates with low-energy IPL sintering were investigated. Simple circuits and radio frequency identification antennas were made by screen-printing Cu nanoink and IPL sintering, demonstrating the technique’s feasibility for practical applications.

  13. Flexography-Printed In2 O3 Semiconductor Layers for High-Mobility Thin-Film Transistors on Flexible Plastic Substrate.

    Science.gov (United States)

    Leppäniemi, Jaakko; Huttunen, Olli-Heikki; Majumdar, Himadri; Alastalo, Ari

    2015-11-25

    Industrially scalable and roll-to-roll-compatible fabrication methods are utilized to fabricate high-mobility (≈8 cm(2) V(-1) s(-1) ) nanocrystalline In2 O3 thin-film transistors (TFTs) on an flexible plastic substrate. Flexographic printing of multiple thin In2 O3 semiconductor layers from precursor-solution is performed on a Al2 O3 gate dielectric obtained via atomic layer deposition. A low-temperature post-contact-annealing step allows control of the TFT device turn-on voltage to ≈0 V for enhancement-mode operation.

  14. Flexible a-Si:H/nc-Si:H tandem thin film silicon solar cells on plastic substrates with i-layers made by hot-wire CVD

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hongbo; Werf, C.H.M. van der; Rath, J.K. [Utrecht University, Faculty of Science, SID - Physics of Devices, Utrecht (Netherlands); Borreman, A. [Helianthos b.v., Arnhem (Netherlands); Schropp, Ruud E.I.

    2008-08-15

    In this letter we report the result of an a-Si:H/nc-Si:H tandem thin film silicon solar mini-module fabricated on plastic foil containing intrinsic silicon layers made by hot-wire CVD (efficiency 7.4%, monolithically series-connected, aperture area 25 cm{sup 2}). We used the Helianthos cell transfer process. The cells were first deposited on a temporary aluminum foil carrier, which allows the use of the optimal processing temperatures, and then transferred to a plastic foil. This letter reports the characteristics of the flexible solar cells obtained in this manner, and compares the results with those obtained on reference glass substrates. The research focus for implementation of the hot-wire CVD technique for the roll-to-roll process is also discussed. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Sensor Technologies on Flexible Substrates

    Science.gov (United States)

    Koehne, Jessica

    2016-01-01

    NASA Ames has developed sensor technologies on flexible substrates integrated into textiles for personalized environment monitoring and human performance evaluation. Current technologies include chemical sensing for gas leak and event monitoring and biological sensors for human health and performance monitoring. Targeted integration include next generation EVA suits and flexible habitats.

  16. Electrochemical deposition of molybdenum sulfide thin films on conductive plastic substrates as platinum-free flexible counter electrodes for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Chao-Kuang; Hsieh, Chien-Kuo, E-mail: jack_hsieh@mail.mcut.edu.tw

    2015-06-01

    In this study, pulsed electrochemical deposition (pulsed ECD) was used to deposit molybdenum sulfide (MoS{sub x}) thin films on indium tin oxide/polyethylene naphthalate (ITO/PEN) substrates as flexible counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The surface morphologies and elemental distributions of the prepared MoS{sub x} thin films were examined using field-emission scanning electron microscope (FE-SEM) equipped with energy-dispersive X-ray spectroscopy. The chemical states and crystallinities of the prepared MoS{sub x} thin films were examined by X-ray photoelectron spectroscopy and X-ray diffraction, respectively. The optical transmission (T (%)) properties of the prepared MoS{sub x} samples were determined by ultraviolet–visible spectrophotometry. Cyclic voltammetry (CV) and Tafel-polarization measurements were performed to analyze the electrochemical properties and catalytic activities of the thin films for redox reactions. The FE-SEM results showed that the MoS{sub x} thin films were deposited uniformly on the ITO/PEN flexible substrates via the pulsed ECD method. The CV and Tafel-polarization curve measurements demonstrated that the deposited MoS{sub x} thin films exhibited excellent performances for the reduction of triiodide ions. The photoelectric conversion efficiency (PCE) of the DSSC produced with the pulsed ECD MoS{sub x} thin-film CE was examined by a solar simulator. In combination with a dye-sensitized TiO{sub 2} working electrode and an iodine-based electrolyte, the DSSC with the MoS{sub x} flexible CE showed a PCE of 4.39% under an illumination of AM 1.5 (100 mW cm{sup −2}). Thus, we report that the MoS{sub x} thin films are active catalysts for triiodide reduction. The MoS{sub x} thin films are prepared at room temperature and atmospheric pressure and in a simple and rapid manner. This is an important practical contribution to the production of flexible low-cost thin-film CEs based on plastic substrates. The MoS{sub x

  17. Integrated silicon and silicon nitride photonic circuits on flexible substrates.

    Science.gov (United States)

    Chen, Yu; Li, Mo

    2014-06-15

    Flexible integrated photonic devices based on crystalline materials on plastic substrates have a promising potential in many unconventional applications. In this Letter, we demonstrate a fully integrated photonic system including ring resonators and grating couplers, based on both crystalline silicon and silicon nitride, on flexible plastic substrate by using the stamping-transfer method. A high yield has been achieved by a simple, yet reliable transfer method without significant performance degradation.

  18. Superhydrophobicity enhancement through substrate flexibility.

    Science.gov (United States)

    Vasileiou, Thomas; Gerber, Julia; Prautzsch, Jana; Schutzius, Thomas M; Poulikakos, Dimos

    2016-11-22

    Inspired by manifestations in nature, microengineering and nanoengineering of synthetic materials to achieve superhydrophobicity has been the focus of much work. Generally, hydrophobicity is enhanced through the combined effects of surface texturing and chemistry; being durable, rigid materials are the norm. However, many natural and technical surfaces are flexible, and the resulting effect on hydrophobicity has been largely ignored. Here, we show that the rational tuning of flexibility can work synergistically with the surface microtexture or nanotexture to enhance liquid repellency performance, characterized by impalement and breakup resistance, contact time reduction, and restitution coefficient increase. Reduction in substrate areal density and stiffness imparts immediate acceleration and intrinsic responsiveness to impacting droplets (∼350 × g), mitigating the collision and lowering the impalement probability by ∼60% without the need for active actuation. Furthermore, we exemplify the above discoveries with materials ranging from man-made (thin steel or polymer sheets) to nature-made (butterfly wings).

  19. Semiconductor films on flexible iridium substrates

    Science.gov (United States)

    Goyal, Amit

    2005-03-29

    A laminate semiconductor article includes a flexible substrate, an optional biaxially textured oxide buffer system on the flexible substrate, a biaxially textured Ir-based buffer layer on the substrate or the buffer system, and an epitaxial layer of a semiconductor. Ir can serve as a substrate with an epitaxial layer of a semiconductor thereon.

  20. Fabrication of high optical transparent and conductive SWNT based transparent conducting film on flexible plastic substrate using ozone as a redox dopant.

    Science.gov (United States)

    Peng, Ke; Liu, Lu-Qi; Gao, Yun; Qu, Mei-Zhen; Zhang, Zhong

    2010-11-01

    In the present work, single-wall carbon nanotubes-transparent conducting films (SWNTs-TCFs) were fabricated at room temperature on a flexible polycarbonate substrate using the ultrosonication-dip-coating technique. Ozone was employed to reduce the sheet resistance of conductive film. As a result, the sheet resistance of film was decreased drastically after 1.5 hr ozone (O3) treatment and could reach up to 170 omega/square at 80% T at 550 nm wavelength. In addition, aminopropyltriethoxysilane (APTS) was further applied as an adhesion promoter in order to enhance the adhesion between the SWNTs films and the substrate. Experimental results show that ATPS can greatly improve the adhesion of SWNTs coating to the substrate without the loss of conductivity.

  1. Spectral and Color Changes of Ag/TiO2 Photochromic Films Deposited on Diffusing Paper and Transparent Flexible Plastic Substrates.

    Science.gov (United States)

    Diop, Daouda K; Simonot, Lionel; Martínez-García, Juan; Hébert, Mathieu; Lefkir, Yaya; Abadias, Grégory; Guérin, Philippe; Babonneau, David; Destouches, Nathalie

    2016-12-12

    Giving paper and polymer photochromic properties under laser irradiation is challenging due to the low resistance of these materials to heat, their flexibility, and their possibly irregular structure. However, we could successfully deposit TiO2/Ag/TiO2 layers stacking on flexible white glossy paper and transparent polyethylene terephalate (PET) substrates using a reactive magnetron sputtering technique, and tailor coloration changes after laser irradiation, alternating visible and ultraviolet (UV) wavelengths. The sample colors are characterized by a panel of chromas depending on the irradiation conditions. We demonstrate that these chroma changes are due to morphological changes of Ag nanoparticles (NPs) after visible laser irradiation of the colored as-deposited sample. The process exhibits a good reversibility after subsequent UV irradiation due to the growth of new metallic Ag NPs. The colors displayed in diffuse reflection by the paper samples are more saturated than the ones displayed in regular transmission by PET samples. We demonstrate the efficiency of the photochromic process on such support by printing high resolution patterns exhibiting different colors depending on the observation conditions.

  2. Flexible SERS Substrates: Challenges and Opportunities

    Science.gov (United States)

    2016-01-28

    multifunctionality to SERS substrates to achieve separation, preconcentration and detection on flexible SERS substrates. Clearly, progress along this...developed a microfluidic device that detects trace concentrations of drugs of abuse in saliva within minutes using SERS . Its operation was demonstrated...substrates without hot spots are demonstrated with SERS enhancements near 108 compared to non-enhancing substrates for the detection of benzenethiol. The

  3. Method For Producing Mechanically Flexible Silicon Substrate

    KAUST Repository

    Hussain, Muhammad Mustafa

    2014-08-28

    A method for making a mechanically flexible silicon substrate is disclosed. In one embodiment, the method includes providing a silicon substrate. The method further includes forming a first etch stop layer in the silicon substrate and forming a second etch stop layer in the silicon substrate. The method also includes forming one or more trenches over the first etch stop layer and the second etch stop layer. The method further includes removing the silicon substrate between the first etch stop layer and the second etch stop layer.

  4. Plasma jet printing for flexible substrates

    Science.gov (United States)

    Gandhiraman, Ram P.; Singh, Eric; Diaz-Cartagena, Diana C.; Nordlund, Dennis; Koehne, Jessica; Meyyappan, M.

    2016-03-01

    Recent interest in flexible electronics and wearable devices has created a demand for fast and highly repeatable printing processes suitable for device manufacturing. Robust printing technology is critical for the integration of sensors and other devices on flexible substrates such as paper and textile. An atmospheric pressure plasma-based printing process has been developed to deposit different types of nanomaterials on flexible substrates. Multiwalled carbon nanotubes were deposited on paper to demonstrate site-selective deposition as well as direct printing without any type of patterning. Plasma-printed nanotubes were compared with non-plasma-printed samples under similar gas flow and other experimental conditions and found to be denser with higher conductivity. The utility of the nanotubes on the paper substrate as a biosensor and chemical sensor was demonstrated by the detection of dopamine, a neurotransmitter, and ammonia, respectively.

  5. Plasma jet printing for flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Gandhiraman, Ram P.; Singh, Eric; Diaz-Cartagena, Diana C.; Koehne, Jessica; Meyyappan, M. [Center for Nanotechnology, NASA Ames Research Center, Moffett Field, California 94035 (United States); Nordlund, Dennis [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

    2016-03-21

    Recent interest in flexible electronics and wearable devices has created a demand for fast and highly repeatable printing processes suitable for device manufacturing. Robust printing technology is critical for the integration of sensors and other devices on flexible substrates such as paper and textile. An atmospheric pressure plasma-based printing process has been developed to deposit different types of nanomaterials on flexible substrates. Multiwalled carbon nanotubes were deposited on paper to demonstrate site-selective deposition as well as direct printing without any type of patterning. Plasma-printed nanotubes were compared with non-plasma-printed samples under similar gas flow and other experimental conditions and found to be denser with higher conductivity. The utility of the nanotubes on the paper substrate as a biosensor and chemical sensor was demonstrated by the detection of dopamine, a neurotransmitter, and ammonia, respectively.

  6. Printed electronic on flexible and glass substrates

    Science.gov (United States)

    Futera, Konrad; Jakubowska, Małgorzata; Kozioł, Grażyna

    2010-09-01

    Organic electronics is a platform technology that enables multiple applications based on organic electronics but varied in specifications. Organic electronics is based on the combination of new materials and cost-effective, large area production processes that provide new fields of application. Organic electronic by its size, weight, flexibility and environmental friendliness electronics enables low cost production of numerous electrical components and provides for such promising fields of application as: intelligent packaging, low cost RFID, flexible solar cells, disposable diagnostic devices or games, and printed batteries [1]. The paper presents results of inkjetted electronics elements on flexible and glass substrates. The investigations was target on characterizing shape, surface and geometry of printed structures. Variety of substrates were investigated, within some, low cost, non specialized substrate, design for other purposes than organic electronic.

  7. Direct transfer of graphene onto flexible substrates

    Science.gov (United States)

    Pimenta, Luiz Gustavo; Song, Yi; Zeng, Tingying; Dresselhaus, Mildred; Kong, Jing; Araujo, Paulo

    2014-03-01

    We explore the direct transfer via lamination of chemical vapor deposition graphene onto different flexible substrates. The transfer method investigated here is fast, simple, and does not require an intermediate transfer membrane, such as polymethylmethacrylate. Various substrates of general interest in research and industry were studied including polytetrafluoroethylene filter membranes, PVC, cellulose nitrate/cellulose acetate filter membranes, polycarbonate, paraffin, polyethylene terephthalate, paper, and cloth. By comparing the properties of these substrates, two critical factors to ensure a successful transfer on bare substrates were identified: the substrate's hydrophobicity and good contact between the substrate and graphene. For substrates that do not satisfy those requirements, polymethylmethacrylate can be used as a surface modifier or glue to ensure successful transfer. Our results can be applied to facilitate present processes and open up directions for applications of chemical vapor deposition (CVD) graphene on flexible substrates. A broad range of applications of CVD graphene can be envisioned, including fabrication of graphene devices for opto/organic electronics, graphene membranes for gas/liquid separation, and ubiquitous electronics with graphene.

  8. Large-area WSe2 electric double layer transistors on a plastic substrate

    KAUST Repository

    Funahashi, Kazuma

    2015-04-27

    Due to the requirements for large-area, uniform films, currently transition metal dichalcogenides (TMDC) cannot be used in flexible transistor industrial applications. In this study, we first transferred chemically grown large-area WSe2 monolayer films from the as-grown sapphire substrates to the flexible plastic substrates. We also fabricated electric double layer transistors using the WSe2 films on the plastic substrates. These transistors exhibited ambipolar operation and an ON/OFF current ratio of ∼104, demonstrating chemically grown WSe2 transistors on plastic substrates for the first time. This achievement can be an important first step for the next-generation TMDC based flexible devices. © 2015 The Japan Society of Applied Physics.

  9. Screen printed UHF antennas on flexible substrates

    Science.gov (United States)

    Janeczek, Kamil; Młożniak, Anna; Kozioł, Grażyna; Araźna, Aneta; Jakubowska, Małgorzata; Bajurko, Paweł

    2010-09-01

    Printed electronics belongs to the most important developing electronics technologies. It provides new possibilities to produce low cost and large area devices. In its range several applications can be distinguished like printed batteries, OLED, biosensors, photovoltaic cells or RFID tags. In the presented investigation, antennas working in UHF frequency range were elaborated. It can be applied in the future for flexible RFID tags. To produce these antennas polymer paste with silver flakes was used. It was deposited on two flexible substrates (foil and photo paper) with screen printing techniques. After printing process surface profile, electrical and microwave parameters of performed antennas were measured using digital multimeter and network analyzer, relatively. Furthermore, a thickness of printed layers was measured.

  10. Advances in the fabrication of graphene transistors on flexible substrates

    Science.gov (United States)

    Lo Verso, Stella; Di Marco, Silvestra; Vinciguerra, Vincenzo; Schilirò, Emanuela; Di Franco, Salvatore; Lo Nigro, Raffaella; Roccaforte, Fabrizio; Zurutuza, Amaia; Centeno, Alba; Ravesi, Sebastiano; Giannazzo, Filippo

    2017-01-01

    Graphene is an ideal candidate for next generation applications as a transparent electrode for electronics on plastic due to its flexibility and the conservation of electrical properties upon deformation. More importantly, its field-effect tunable carrier density, high mobility and saturation velocity make it an appealing choice as a channel material for field-effect transistors (FETs) for several potential applications. As an example, properly designed and scaled graphene FETs (Gr-FETs) can be used for flexible high frequency (RF) electronics or for high sensitivity chemical sensors. Miniaturized and flexible Gr-FET sensors would be highly advantageous for current sensors technology for in vivo and in situ applications. In this paper, we report a wafer-scale processing strategy to fabricate arrays of back-gated Gr-FETs on poly(ethylene naphthalate) (PEN) substrates. These devices present a large-area graphene channel fully exposed to the external environment, in order to be suitable for sensing applications, and the channel conductivity is efficiently modulated by a buried gate contact under a thin Al2O3 insulating film. In order to be compatible with the use of the PEN substrate, optimized deposition conditions of the Al2O3 film by plasma-enhanced atomic layer deposition (PE-ALD) at a low temperature (100 °C) have been developed without any relevant degradation of the final dielectric performance.

  11. Flexible organic light emitting diodes fabricated on biocompatible silk fibroin substrate

    Science.gov (United States)

    Liu, Yuqiang; Xie, Yuemin; Liu, Yuan; Song, Tao; Zhang, Ke-Qin; Liao, Liangsheng; Sun, Baoquan

    2015-10-01

    Flexible and biodegradable electronics are currently under extensive investigation for biocompatible and environmentally-friendly applications. Synthetic plastic foils are widely used as substrates for flexible electronics. But typical plastic substrates such as polyethylene naphthalate (PEN) could not be degraded in a natural bio-environment. A great demand still exists for a next-generation biocompatible and biodegradable substrate for future application. For example, electronic devices can be potentially integrated into the human body. In this work, we demonstrate that the biocompatible and biodegradable natural silk fibroin (SF) films embedded with silver nanowires (AgNWs) mesh could be employed as conductive transparent substrates to fabricate flexible organic light emitting diodes (OLEDs). Compared with commercial PEN substrates coated with indium tin oxide, the AgNWs/SF composite substrates exhibit a similar sheet resistance of 12 Ω sq-1, a lower surface roughness, as well as a broader light transmission range. Flexible OLEDs based on AgNWs/SF substrates achieve a current efficiency of 19 cd A-1, demonstrating the potential of the flexible AgNWs/SF films as conductive and transparent substrates for next-generation biodegradable devices.

  12. Component placement on flexible and/or strechable substrates

    NARCIS (Netherlands)

    Koetse, M.M.; Schoo, H.F.M.

    2011-01-01

    According to one aspect, the invention provides a method of placement of a component on a stretchable substrate, comprising the steps of providing a base substrate having a stretchable substrate layer, providing a flexible foil comprising an integral arrangement (20) of a multiple of flexible foil

  13. Polarimetric studies of polyethylene terephtalate flexible substrates

    Science.gov (United States)

    Stchakovsky, M.; Garcia-Caurel, E.; Warenghem, M.

    2008-12-01

    Polymer sheets are currently used worldwide in a wide range of applications. The manufacturing process of these sheets involves extruding machines that stretch the material in both lateral and longitudinal directions with respect to the machine direction, thus inducing birefringence. In most cases, the film obtained is optically biaxial. Polarimetric spectroscopy (Ellipsometry and Mueller Matrix) combined with conoscopic observation are the methods of choice to study these properties. In this work we report an analysis of commercially available polyethylene terephtalate (PET) films used as substrate for food packaging as well as for embedded electronic devices such as solar cells or flexible displays. Initial observation of these films through polarizing microscope in conoscopic mode reveals first the trace of optical axis plane with respect to the film surface and second, whether the optical axis is acute or not. This preliminary study allows optimal sample positioning for further polarimetric studies. The measurements and modelling are done in both reflection and transmission mode on several spectroscopic polarimetric setups from UV to NIR. The models give as a main result, the dielectric tensor of the film as well as its orientation with respect to the laboratory reference frame.

  14. Pd thin films on flexible substrate for hydrogen sensor

    Energy Technology Data Exchange (ETDEWEB)

    Öztürk, Sadullah [Fatih Sultan Mehmet Vakıf University, Engineering Faculty, Istanbul (Turkey); Kılınç, Necmettin, E-mail: nkilinc@nigde.edu.tr [Nigde University, Mechatronics Engineering Department, 51245 Nigde (Turkey); Nigde University, Nanotechnology Application and Research Center, 51245 Nigde (Turkey)

    2016-07-25

    In this work, palladium (Pd) thin films were prepared via RF sputtering method with various thicknesses (6 nm, 20 nm and 60 nm) on both a flexible substrate and a hard substrate. Hydrogen (H{sub 2}) sensing properties of Pd films on flexible substrate have been investigated depending on temperatures (25–100 °C) and H{sub 2} concentrations (600 ppm – 10%). The effect of H{sub 2} on structural properties of the films was also studied. The films were characterized by Scanning Electron Microscopy (SEM) and X-ray diffraction. It is found that whole Pd films on hard substrate show permanent structural deformation after exposed to 10% H{sub 2} for 30 min. But, this H{sub 2} exposure does not causes any structural deformation for 6 nm Pd film on flexible substrate and 6 nm Pd film on flexible substrate shows reversible sensor response up to 10% H{sub 2} concentration without any structural deformation. On the other hand, Pd film sensors that have the thicknesses 20 nm and 60 nm on flexible substrate are irreversible for higher H{sub 2} concentration (>2%) with film deformation. The sensor response of 6 nm Pd film on flexible substrate increased with increasing H{sub 2} concentration up 4% and then saturated. The sensitivity of the film decreased with increasing operation temperature. - Highlights: • Pd thin films fabricated by RF sputtering on both flexible and hard substrates. • Structural deformation observed for films on hard substrate after exposing 10% H{sub 2}. • 6 nm Pd film on flexible substrate shows reversible sensor response up to 10% H{sub 2}. • H{sub 2} sensing properties of film on flexible substrate investigated depending on temperature and concentration. • The sensitivity of the film decreased with increasing operation temperature.

  15. Flexible and foldable paper-substrate thermoelectric generator (teg)

    KAUST Repository

    Rojas, Jhonathan Prieto

    2017-08-24

    Flexible and foldable paper-substrate thermoelectric generators (TEGs) and methods for making the paper-substrate TEGs are disclosed. A method includes depositing a plurality of thermocouples in series on a paper substrate to create a paper-substrate TEG, wherein the plurality of thermocouples is deposited between two contact points of the paper-substrate TEG. The method may also include setting the power density and maximum achievable temperature gradient of the paper-substrate TEG by folding the paper-substrate TEG. A paper-substrate TEG apparatus may include a paper substrate and a plurality of thermocouples deposited in series on the paper substrate between two contact points of the paper-substrate TEG, wherein the power density and maximum achievable temperature gradient of the paper-substrate TEG is set by folding the paper-substrate TEG.

  16. Direct writing patterns for electroless plated copper thin film on plastic substrates.

    Science.gov (United States)

    Liao, Ying-Chih; Kao, Zhen-Kai

    2012-10-24

    A simple and efficient method is developed to create conductive copper thin films on polymer surfaces. Instead of regular palladium colloid inks, micropatterns of silver nitrate inks, which serve as an activating agent for copper plating, were printed and dried on flexible plastic substrates. The printed plastic sheets were then immersed in an electroless copper plating bath at 55 °C for 2 min to create copper thin films on the printed patterns. The prepared copper films have an electrical conductivity as high as 83% of bulk copper and show good adhesion on PET or PI substrates.

  17. Novel Flexible Plastic-Based Solar Cells

    Science.gov (United States)

    2009-11-30

    replacing the dyes because QDs have large extinction coefficient and are easy to fabricate directly on the Ti02 surface. We have investigated the direct...source for the dipping method. Porous Ti02 , doctor bladed on a FTO coated glass substrate, was immersed in the Cd source for 1 minute and S source...we determined that the 7/7 ratio of CdS and CdSe was the best number of cycles using SILAR process in transparent Ti02 nanostructures with 20~50nm

  18. Direct Printing of Graphene onto Plastic Substrates.

    Science.gov (United States)

    Hines, Daniel; Lock, Evgeniya; Walton, Scott; Baraket, Mira; Laskoski, Matthew; Mulvaney, Shawn; Sheehan, Paul; Lee, Woo; Robinson, Jeremy

    2011-03-01

    Graphene films have been synthesized on metal foils using CVD growth and have the potential to be compatible with roll-to-roll printing. To be usable in electronic devices, these films need to be removed from the metallic substrate. Currently this is accomplished by spin coating a polymer film over the graphene and chemically etching away the metal substrate. We have developed a direct printing method that allows graphene films to be printed off the metal substrate onto a polymer substrate. This printing process does not generate chemical waste, is compatible with roll-to-toll processing and renders the metal foil reusable. Adhesion of the graphene film to the polymer substrate is established by attaching perfluorophenylazides (PFPA) azide linker molecules to a plasma activated polymer surface. The transfer printing was performed by placing the PFPA treated polymer surface in contact with a graphene covered Cu foil and heating under pressure. Graphene films successfully printed onto a polystyrene substrate have been characterized by Raman spectroscopy and electrical measurements revealed the presence of Gr on the polymer surface. Details of the printing process along with characteristics of the graphene film after printing will be presented.

  19. Mechanically flexible optically transparent porous mono-crystalline silicon substrate

    KAUST Repository

    Rojas, Jhonathan Prieto

    2012-01-01

    For the first time, we present a simple process to fabricate a thin (≥5μm), mechanically flexible, optically transparent, porous mono-crystalline silicon substrate. Relying only on reactive ion etching steps, we are able to controllably peel off a thin layer of the original substrate. This scheme is cost favorable as it uses a low-cost silicon <100> wafer and furthermore it has the potential for recycling the remaining part of the wafer that otherwise would be lost and wasted during conventional back-grinding process. Due to its porosity, it shows see-through transparency and potential for flexible membrane applications, neural probing and such. Our process can offer flexible, transparent silicon from post high-thermal budget processed device wafer to retain the high performance electronics on flexible substrates. © 2012 IEEE.

  20. Flexible, light trapping substrates for organic photovoltaics

    Science.gov (United States)

    Park, Yoonseok; Berger, Jana; Tang, Zheng; Müller-Meskamp, Lars; Lasagni, Andrés Fabián; Vandewal, Koen; Leo, Karl

    2016-08-01

    Micro-structured organic photovoltaic (OPV) devices on polyethylene terephthalate substrates are produced using direct laser interference patterning (DLIP). The performance of organic solar cells on these substrates is improved by a factor of 1.16, and a power conversion efficiency of 7.70% is achieved. We show that a shorter spatial period of the pattern allows for a stronger light trapping effect in solar cell, as it leads to a longer light path. Moreover, since the patterned structures are located on the outside of the fully encapsulated OPV devices, there are no problems with the roughness induced shunts.

  1. Microwave flexible transistors on cellulose nanofibrillated fiber substrates

    Science.gov (United States)

    Seo, Jung-Hun; Chang, Tzu-Hsuan; Lee, Jaeseong; Sabo, Ronald; Zhou, Weidong; Cai, Zhiyong; Gong, Shaoqin; Ma, Zhenqiang

    2015-06-01

    In this paper, we demonstrate microwave flexible thin-film transistors (TFTs) on biodegradable substrates towards potential green portable devices. The combination of cellulose nanofibrillated fiber (CNF) substrate, which is a biobased and biodegradable platform, with transferrable single crystalline Si nanomembrane (Si NM), enables the realization of truly biodegradable, flexible, and high performance devices. Double-gate flexible Si NM TFTs built on a CNF substrate have shown an electron mobility of 160 cm2/V.s and fT and fmax of 4.9 GHz and 10.6 GHz, respectively. This demonstration proves the microwave frequency capability and, considering today's wide spread use of wireless devices, thus indicates the much wider utility of CNF substrates than that has been demonstrated before. The demonstration may also pave the way toward portable green devices that would generate less persistent waste and save more valuable resources.

  2. Laser sintering of conductive carbon paste on plastic substrate

    Science.gov (United States)

    Kinzel, Edward C.; Kelkar, Rohan; Xu, Xianfan

    2010-02-01

    This work investigates fabrication of functional conductive carbon paste onto a plastic substrate using a laser. The method allows simultaneous sintering, patterning, and functionalization of the carbon paste. Experiments are carried out to optimize the laser processing parameters. It is shown that sheet resistance values obtained by laser sintering are close to the one specified by the manufacturer using conventional sintering method. Additionally, a heat transfer analysis using numerical methods is conducted to understand the relationship between the temperature during sintering and the sheet resistance values of sintered carbon wires. The process developed in this work has the potential of producing carbon-based electronic components on low cost plastic substrates.

  3. Progress Towards III-V Photovoltaics on Flexible Substrates

    Science.gov (United States)

    McNatt, Jeremiah S.; Pal, AnnaMaria T.; Clark, Eric B.; Sayir, Ali; Raffaelle, Ryne P.; Bailey, Christopher G.; Hubbard, Seth M.; Maurer, William F.; Fritzemeier, Les

    2008-01-01

    Presented here is the recent progress of the NASA Glenn Research Center OMVPE group's efforts in the development of high efficiency thin-film polycrystalline III-V photovoltaics on optimum substrates. By using bulk polycrystalline germanium (Ge) films, devices of high efficiency and low mass will be developed and incorporated onto low-cost flexible substrates. Our progress towards the integration of high efficiency polycrystalline III-V devices and recrystallized Ge films on thin metal foils is discussed.

  4. Transparent electronics based on transfer printed aligned carbon nanotubes on rigid and flexible substrates.

    Science.gov (United States)

    Ishikawa, Fumiaki N; Chang, Hsiao-Kang; Ryu, Koungmin; Chen, Po-Chiang; Badmaev, Alexander; Gomez De Arco, Lewis; Shen, Guozhen; Zhou, Chongwu

    2009-01-27

    We report high-performance fully transparent thin-film transistors (TTFTs) on both rigid and flexible substrates with transfer printed aligned nanotubes as the active channel and indium-tin oxide as the source, drain, and gate electrodes. Such transistors have been fabricated through low-temperature processing, which allowed device fabrication even on flexible substrates. Transparent transistors with high effective mobilities (approximately 1300 cm(2) V(-1) s(-1)) were first demonstrated on glass substrates via engineering of the source and drain contacts, and high on/off ratio (3 x 10(4)) was achieved using electrical breakdown. In addition, flexible TTFTs with good transparency were also fabricated and successfully operated under bending up to 120 degrees . All of the devices showed good transparency (approximately 80% on average). The transparent transistors were further utilized to construct a fully transparent and flexible logic inverter on a plastic substrate and also used to control commercial GaN light-emitting diodes (LEDs) with light intensity modulation of 10(3). Our results suggest that aligned nanotubes have great potential to work as building blocks for future transparent electronics.

  5. Printed electronic switch on flexible substrates using printed microcapsules

    NARCIS (Netherlands)

    Cate, A.T. ten; Gaspar, C.H.; Virtanen, H.L.K.; Stevens, R.S.A.; Koldeweij, R.B.J.; Olkkonen, J.T.; Rentrop, C.H.A.; Smolander, M.H.

    2014-01-01

    Printed electronics, the manufacturing of electronic components on large, flexible, and low-cost substrates by printing techniques, can facilitate widespread, very low-cost electronics for consumer applications and disposable devices. New technologies are needed to create functional components in th

  6. The technology of microcircuit assembly on flexible polyimide substrate

    Directory of Open Access Journals (Sweden)

    Plis N. I.

    2010-10-01

    Full Text Available The research is devoted to technology of microcircuit assembly on flexible polyimide substrate. It is proved that such microcircuits provide high reliability and have advantage over other IC models when applied in hermetic micro-assemblies in microelectronic devices that operate under high accelerations, shocks and strong radiation.

  7. Printed electronic switch on flexible substrates using printed microcapsules

    NARCIS (Netherlands)

    Cate, A.T. ten; Gaspar, C.H.; Virtanen, H.L.K.; Stevens, R.S.A.; Koldeweij, R.B.J.; Olkkonen, J.T.; Rentrop, C.H.A.; Smolander, M.H.

    2014-01-01

    Printed electronics, the manufacturing of electronic components on large, flexible, and low-cost substrates by printing techniques, can facilitate widespread, very low-cost electronics for consumer applications and disposable devices. New technologies are needed to create functional components in

  8. Doped polymer electrodes for high performance ferroelectric capacitors on plastic substrates

    KAUST Repository

    Khan, M. A.

    2012-10-03

    Flexible ferroelectric capacitors with doped polymer electrodes have been fabricated on plastic substrates with performance as good as metal electrodes. The effect of doping on the morphology of polymer electrodes and its impact on device performance have been studied. Improved fatigue characteristics using doped and undoped poly (3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) electrodes versus metal electrodes are observed. It is shown that the polymer electrodes follow classical ferroelectric and dielectric responses, including series resistance effects. The improved device characteristics obtained using highly conducting doped PEDOT:PSS suggest that it may be used both as an electrode and as global interconnect for all-polymer transparent circuits on flexible substrates.

  9. Weather resistance of inkjet prints on plastic substrates

    Directory of Open Access Journals (Sweden)

    Rozália Szentgyörgyvölgyi

    2015-06-01

    Full Text Available The development of wide format inkjet printers made the technology available for large area commercials. Outdoor advertising uses a wide range of substrate including paperboard, vinyl, canvas, mesh; the material of the substrate itself has to endure the physical and chemical effects of local weather. Weather elements (humidity, wind, solar irradiation degrade printed products inevitably; plastic products have better resistance against them, than paper based substrates. Service life of the printed product for outdoor application is a key parameter from the customer’s point of view. There are two ways to estimate expected lifetime: on site outdoor testing or laboratory testing. In both cases weathering parameters can be monitored, however laboratory testing devices may produce the desired environmental effects and thus accelerate the aging process. Our research objective was to evaluate the effects of artificial weathering on prints produced by inkjet technology on plastic substrates. We used a large format CMYK inkjet printer (Mutoh Rockhopper II, with Epson DX 4 print heads to print our test chart on two similar substrates (PVC coated tarpaulins with grammages 400 g/m2 and 440 g/m2. Specimen were aged in an Atlas Suntest XLS+ material tester device for equal time intervals. We measured and calculated the gradual changes of the optical properties (optical density, tone value, colour shifts of the test prints.

  10. Fatigue properties of Graphene interconnects on flexible substrates

    Science.gov (United States)

    Paradee, Gary

    This thesis represents the first determination of the fatigue behavior of Graphene as interconnect material electronic components on flexible substrates. The potential application of this interconnect material is for displays on flexible substrates where fatigue resistance is required due to the stress placed on the interconnect during mechanical bending. As the display is cyclically deformed (fatigued) during normal operation, cracks in the interconnect layer initiate and propagate leading to the lineout failure condition. The major contribution of this work is to show that Graphene is a superior interconnect material to the present state of the art Indium Tin Oxide (ITO) due to its electrical, optical and mechanical properties. The experimental approach in this thesis is based on Graphene samples which were fabricated on Silicon Nitrite (Si3N4)/Polyethylene Naphthalate (PEN) substrates. For comparison, both patterned and uniform ITO films ITO films on Si3N4/PEN were fabricated. The results of the in-depth characterization of Graphene are reported and based on Atomic Force Microscopy (AFM), Raman Spectroscopy and Scanning Electron Microscopy (SEM) are reported. The fatigue characteristics of ITO were determined at stress amplitudes ranging from 2000 MPa to 400 MPa up to 5000 cycles. The fatigue characteristics of Graphene were determined at stress amplitudes ranging from 80 GPa to 40 GPa up to 5000 cycles. The fatigue S-N curves were determined and showed that Graphene's endurance limit is 40 GPa. Beyond the endurance limit, there is no observable high cycle or low cycle fatigue indication for Graphene on a flexible substrate such as PEN. The microstructural analysis by SEM and AFM did not reveal normal fatigue crack growth and propagation. This thesis presents the first comprehensive behavior of Graphene in a bending fatigue stress environment present in numerous flexible electronic applications. The design and stress environments for safe operation has been

  11. Large area flexible SERS active substrates using engineered nanostructures

    Science.gov (United States)

    Chung, Aram J.; Huh, Yun Suk; Erickson, David

    2011-07-01

    Surface enhanced Raman scattering (SERS) is an analytical sensing method that provides label-free detection, molecularly specific information, and extremely high sensitivity. The Raman enhancement that makes this method attractive is mainly attributed to the local amplification of the incident electromagnetic field that occurs when a surface plasmon mode is excited at a metallic nanostructure. Here, we present a simple, cost effective method for creating flexible, large area SERS-active substrates using a new technique we call shadow mask assisted evaporation (SMAE). The advantage of large, flexible SERS substrates such as these is they have more area for multiplexing and can be incorporated into irregular surfaces such as clothing. We demonstrate the formation of four different types of nanostructure arrays (pillar, nib, ellipsoidal cylinder, and triangular tip) by controlling the evaporation angle, substrate rotation, and deposition rate of metals onto anodized alumina nanoporous membranes as large as 27 mm. In addition, we present experimental results showing how a hybrid structure comprising of gold nanospheres embedded in a silver nano-pillar structure can be used to obtain a 50× SERS enhancement over the raw nanoparticles themselves.Surface enhanced Raman scattering (SERS) is an analytical sensing method that provides label-free detection, molecularly specific information, and extremely high sensitivity. The Raman enhancement that makes this method attractive is mainly attributed to the local amplification of the incident electromagnetic field that occurs when a surface plasmon mode is excited at a metallic nanostructure. Here, we present a simple, cost effective method for creating flexible, large area SERS-active substrates using a new technique we call shadow mask assisted evaporation (SMAE). The advantage of large, flexible SERS substrates such as these is they have more area for multiplexing and can be incorporated into irregular surfaces such as

  12. Better Back Contacts for Solar Cells on Flexible Substrates

    Science.gov (United States)

    Woods, Lawrence M.; Ribelin, Rosine M.

    2006-01-01

    Improved low-resistance, semitransparent back contacts, and a method of fabricating them, have been developed for solar photovoltaic cells that are made from thin films of I-III-VI2 semiconductor materials on flexible, high-temperatureresistant polyimide substrates or superstrates. The innovative aspect of the present development lies in the extension, to polyimide substrates or superstrates, of a similar prior development of improved low-resistance, semitransparent back contacts for I-III-VI2 solar cells on glass substrates or superstrates. A cell incorporating this innovation can be used either as a stand-alone photovoltaic device or as part of a monolithic stack containing another photovoltaic device that utilizes light of longer wavelengths.

  13. Colloidal quantum dot solar cells on curved and flexible substrates

    KAUST Repository

    Kramer, Illan J.

    2014-10-20

    © 2014 AIP Publishing LLC. Colloidal quantum dots (CQDs) are semiconductor nanocrystals synthesized with, processed in, and deposited from the solution phase, potentially enabling low-cost, facile manufacture of solar cells. Unfortunately, CQD solar cell reports, until now, have only explored batch-processing methods - such as spin-coating - that offer limited capacity for scaling. Spray-coating could offer a means of producing uniform colloidal quantum dot films that yield high-quality devices. Here, we explore the versatility of the spray-coating method by producing CQD solar cells in a variety of previously unexplored substrate arrangements. The potential transferability of the spray-coating method to a roll-to-roll manufacturing process was tested by spray-coating the CQD active layer onto six substrates mounted on a rapidly rotating drum, yielding devices with an average power conversion efficiency of 6.7%. We further tested the manufacturability of the process by endeavoring to spray onto flexible substrates, only to find that spraying while the substrate was flexed was crucial to achieving champion performance of 7.2% without compromise to open-circuit voltage. Having deposited onto a substrate with one axis of curvature, we then built our CQD solar cells onto a spherical lens substrate having two axes of curvature resulting in a 5% efficient device. These results show that CQDs deposited using our spraying method can be integrated to large-area manufacturing processes and can be used to make solar cells on unconventional shapes.

  14. Large area flexible lighting foils using distributed bare LED dies on polyester substrates

    NARCIS (Netherlands)

    Ende, D.A. van den; Kusters, R.H.L.; Cauwe, M.; Waal, A. van der; Brand, J. van den

    2013-01-01

    Integration of LEDs on flexible foil substrates is of interest for flexible lighting applications and for backlights for flexible displays. Such a large area lighting device can be made by integrating a matrix of closely spaced LEDs on a flexible foil substrate. Preferably, these LEDs are integrated

  15. Filopodia: A Rapid Structural Plasticity Substrate for Fast Learning

    Directory of Open Access Journals (Sweden)

    Ahmet S. Ozcan

    2017-06-01

    Full Text Available Formation of new synapses between neurons is an essential mechanism for learning and encoding memories. The vast majority of excitatory synapses occur on dendritic spines, therefore, the growth dynamics of spines is strongly related to the plasticity timescales. Especially in the early stages of the developing brain, there is an abundant number of long, thin and motile protrusions (i.e., filopodia, which develop in timescales of seconds and minutes. Because of their unique morphology and motility, it has been suggested that filopodia can have a dual role in both spinogenesis and environmental sampling of potential axonal partners. I propose that filopodia can lower the threshold and reduce the time to form new dendritic spines and synapses, providing a substrate for fast learning. Based on this proposition, the functional role of filopodia during brain development is discussed in relation to learning and memory. Specifically, it is hypothesized that the postnatal brain starts with a single-stage memory system with filopodia playing a significant role in rapid structural plasticity along with the stability provided by the mushroom-shaped spines. Following the maturation of the hippocampus, this highly-plastic unitary system transitions to a two-stage memory system, which consists of a plastic temporary store and a long-term stable store. In alignment with these architectural changes, it is posited that after brain maturation, filopodia-based structural plasticity will be preserved in specific areas, which are involved in fast learning (e.g., hippocampus in relation to episodic memory. These propositions aim to introduce a unifying framework for a diversity of phenomena in the brain such as synaptogenesis, pruning and memory consolidation.

  16. CMOS vertical hall magnetic sensors on flexible substrate

    OpenAIRE

    2016-01-01

    This paper presents the realization of different\\ud Vertical Hall Sensors (VHSs) implemented using a 0.18-μm\\ud CMOS technology and mounted on flexible substrates. Various\\ud geometries of VHS have been studied to obtain the optimum\\ud sensor device dimension and shape. COMSOL multiphysics\\ud simulation results are validated with respect to the electrical\\ud behaviour of an 8-resistor Verilog-A model implemented in\\ud Cadence environment. Simulation and measurement results are in\\ud good agre...

  17. NOVEL FLEXIBLE PVC COMPOUNDS CHARACTERIZED BY IMPROVED SUSTAINABILITY AND REDUCED PLASTICIZER MIGRATION

    OpenAIRE

    Pannico, Marianna

    2010-01-01

    In this thesis three different strategies were adopted to reduce the migration of plasticizer from flexible PVC-based compounds: chemical cross-linking of flexible PVC, the use of polymeric plasticizers (linear and hyper-branched) as an alternative to monomeric ones, the addition of CPE to flexible PVC as a physical barrier. The physical, chemical, mechanical and tribological properties were studied in order to achieve materials with desired performance.

  18. Effect of substrate bias on the structural and electrical properties of sputtered Mo thin films on flexible substrates.

    Science.gov (United States)

    Xu, Jiaxiong

    2016-07-04

    The metal molybdenum (Mo) thin films deposited on flexible substrates can act as the contact electrode of flexible Cu(In,Ga)Se2 or Cu2ZnSn(S,Se)4 solar cells. In this work, in order to enhance the structural and electrical characteristics of flexible Mo thin films, a negative substrate bias was applied during the direct current sputtering of Mo thin films. The flexible substrates used for growing the Mo films were stainless steel foils and polyimides. The characteristics of Mo thin films were studied by x-ray diffraction and sheet resistance measurements. The measured results reveal that an optimal value of negative substrate bias can be found for improving the electrical and structural characteristics of Mo thin films on flexible substrates. The minimum sheet resistances of Mo thin films are 2.50 Ω/sq and 2.73 Ω/sq for the stainless steel foil and polyimide substrates, respectively.

  19. SILICON NEEDLE ARRAY ON FLEXIBLE SUBSTRATE FOR FLUID TRANSFER

    Institute of Scientific and Technical Information of China (English)

    MA Bin; GAN Zhiyin; LIU Sheng

    2006-01-01

    Transdermal delivery is an attractive alternative, but it is limited by the extremely low permeability of skin. To solve this problem, a novel means-micro needle array based on micro electro-mechanical system (MEMS) technology, is provided to increase permeability of human skin with efficiency, safety and painless delivery. The fabrication method consists of a sequence of deep-reactive ion etching (DRIE), anisotropic wet etching and conformal thin film deposition. The novel technology can enable the realization of micro fabricated micro needle array on a flexible silicon substrate. The micro needle array can be mounted on non-planar surface or even on flexible objects such as a human fingers and arms. The fabricated hollow wall straight micro needles are 200 μm in length, 30 μm inner diameter, and 50 μm outer diameter with 250 μm center-to-center spacing.Flow rate test proves that the polymeric base construction is important to function of micro needles array in package. Glucose solvent tests show that surface tension is the dominant force to affect the characters of flow in micro needles channel.

  20. Flexible diode of polyaniline/ITO heterojunction on PET substrate

    Science.gov (United States)

    Bera, A.; Deb, K.; Kathirvel, V.; Bera, T.; Thapa, R.; Saha, B.

    2017-10-01

    Hybrid organic-inorganic heterojunction between polyaniline and ITO film coated on flexible polyethylene terephthalate (PET) substrate has been prepared through vapor phase polymerization process. Polaron and bipolaron like defect states induced hole transport and exceptional mobility makes polyaniline a noble hole transport layer. Thus a p-n junction has been obtained between the hole transport layer of polyaniline and highly conductive n-type layer of ITO film. The synthesis process was carried out using FeCl3 as polymerizing agent in the oxidative chemical polymerization process. The prepared polyaniline has been found to be crystalline on characterization through X-ray diffraction measurement. X-ray photoelectron spectroscopic measurements were done for compositional analysis of the prepared film. The UV-vis-NIR absorbance spectra obtained for polyaniline shows the characteristics absorbance as observed for highly conductive polyaniline and confirms the occurrence of partially oxidized emeraldine form of polyaniline. The energy band gap of the polyaniline has been obtained as 2.52 eV, by analyzing the optical transmittance spectra. A rectifying behavior has been observed in the electrical J-V plot, which is of great significance in designing polymer based flexible electronic devices.

  1. FINITE ELEMENT ANALYSIS OF SUBSTRATE LOCAL PLASTIC DEFORMATION INDUCED BY CRACKED THIN HARD FILM

    Institute of Scientific and Technical Information of China (English)

    Zhu Youli; Ro(z)niatowski K; Kurzydlowski K; Huang Yuanlin; Xu Binshi

    2004-01-01

    It has been postulated that, with tensile loading conditions, micro-cracks on thin hard film act as stress concentrators enhancing plastic deformation of the substrate material in their vicinity. Under favorable conditions the localized plastic flow near the cracks may turn into macroscopic plastic strain thus affects the plasticity behaviors of the substrate. This phenomenon is analyzed quantitatively with finite element method with special attention focused on the analysis and discussion of the effects of plastic work hardening rate, film thickness and crack depth on maximum plastic strain, critical loading stress and the size of the local plastic deformation zone. Results show that micro-cracks on thin hard film have unnegligible effects on the plasticity behaviors of the substrate material under tensile loading.

  2. Optimization of plasmonic enhancement of fluorescence on plastic substrates.

    Science.gov (United States)

    Nooney, Robert I; Stranik, Ondrej; McDonagh, Colette; MacCraith, Brian D

    2008-10-07

    In this work, we report on the uniform deposition of tailored plasmonic coatings on polymer substrates and on the distance dependence of the plasmonic enhancement of a fluorescent dye. Silver, gold, and silver/gold alloy nanoparticles (NPs) with a range of diameters were synthesized using chemical techniques and characterized using UV-vis absorption spectroscopy, transmission electron microscopy (TEM), and atomic force microscopy (AFM). Reproducible polyelectrolyte (PEL) layers, which were deposited on plastic microwell plates using a layer-by-layer technique, served as both a stable and uniform substrate for deposition of the NPs as well as providing spacer layers of known thickness between the NPs and the fluorescent dye. A maximum enhancement factor of approximately 11 was measured for 60 nm diameter pure silver NPs, for a dye-NP separation of approximately 3 nm. A shift in the localized surface plasmon resonance (LSPR) wavelength as a function of the effective refractive index of the PEL layers was also observed, and the measured shifts show a similar trend with theoretical predictions. This work will contribute toward the rational design of optical biochip platforms based on plasmon-enhanced fluorescence.

  3. A plastic-composite-plastic structure high performance flexible energy harvester based on PIN-PMN-PT single crystal/epoxy 2-2 composite

    Science.gov (United States)

    Zeng, Zhou; Gai, Linlin; Wang, Xian; Lin, Di; Wang, Sheng; Luo, Haosu; Wang, Dong

    2017-03-01

    We present a high performance flexible piezoelectric energy harvester constituted by a Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystal/epoxy 2-2 composite flake, a polyethylene terephthalate (PET) substrate, and a PET cover, which is capable of harvesting energy from biomechanical movements. Electrical properties of the device under different epoxy volume fractions, load resistances, and strains are studied systematically. Both theoretical and experimental results show that the plastic-composite-plastic structure contributes to the flexibility of the device, and a high performance bulk PIN-PMN-PT single crystal (a thickness of 50 μm) results in its high electrical output. At a low excitation frequency of 4.2 Hz, the optimal flexible energy harvester (with ve = 21%) can generate a peak voltage of 12.9 V and a maximum power density of 0.28 mW/cm3 under a bending radius of 10.5 mm, and maintain its performance after 40 000 bending-unbending cycles. High flexibility and excellent electrical output at low operational frequency demonstrate the promise of the device in biomechanical motion energy harvesting for wireless and portable low-power electronics.

  4. Hyperbranched poly(epsilon-caprolactone) as a nonmigrating alternative plasticizer for phthalates in flexible PVC.

    Science.gov (United States)

    Choi, Jeongsoo; Kwak, Seung-Yeop

    2007-05-15

    Hyperbranched (dendritic) poly(epsilon-caprolactone)s (HPCLs) were synthesized to have architectural variations, which are the different lengths of linear segments and different numbers of branches, and were used as plasticizers for flexible poly(vinyl chloride) (PVC). The plasticization efficiency estimated by the lowering of glass transition temperature and the enhancement in ultimate elongation indicated that the HPCLs with the shorter linear segments and the larger number of branches imparted as high flexibility as di(ethylhexyl) phthalate (DEHP) and much higher flexibility than their linear analogue, linear poly(epsilon-caprolactone), which is one of currently used polymer plasticizers. Volatility, extractability, and exudation tests for PVC/HPCL samples showed that there was no plasticizer migration even at very harsh condition, while ca. 7-78% of additives in PVC/DEHP was migrated out of samples, indicating that the HPCL can be used as an alternative plasticizer to remove the potential health risk from migrating phthalates during end use.

  5. High-performance rectifiers fabricated on a flexible substrate

    Science.gov (United States)

    Etor, David; Dodd, Linzi E.; Wood, David; Balocco, Claudio

    2016-11-01

    We report on the fabrication and testing of metal-insulator-metal (MIM) diodes on a flexible substrate where the thin insulating layer self-assembles as a monolayer sandwiched between the two metal electrodes. The current-voltage characteristic has a strong asymmetry and non-linearity at zero-bias. The diodes have a typical zero-bias resistance of 80 kΩ, a zero-bias curvature coefficient of 5.5 V-1, and a voltage responsivity of 3.1 kV/W at a frequency of 1 GHz. The fabrication yield was over 90%, and an encapsulation method to prevent MIM junction degradation has also been developed. The diodes show no significant degradation in performance when the substrate is stressed in a one-off bending experiment, although extensive testing does produce some loss in quality. The fabrication process is simple, cost effective, and carried out at low temperature, opening up the possibility of roll-to-roll volume manufacturing of fast MIM diodes.

  6. A ph sensor based on a flexible substrate

    Science.gov (United States)

    Huang, Wen-Ding

    implanted inside the esophagus. Our pH electrode can monitor the pH changes of gastric juice in real time when the reflux happening in the esophagus. Our micro flexible pH sensor performed clear responses in each distinct pH reflux episode quickly and accurately comparing with the other commercial pH monitoring system. For the food freshness monitoring applications, we used the flexible pH sensor as a freshness indicator to monitor the pH changing profile during the food spoilage procedure. The sensor was then embedded with radio frequency identification (RFID) based passive telemetry enabling remote monitoring of food freshness. In the result, our pH-wireless RFID system presented 633Hz/pH of the sensitivity in the frequency calibration. The calibration of stability and dynamical response of the RFID system were also demonstrated before the test on food freshness monitoring. Finally, a white fish meat for long term spoilage procedure monitoring was applied and tested by using our wireless IrOx pH sensing system. Our RFID pH sensing module is able to monitor, collect and transmit the pH information continuously for 18 hours during the food spoilage procedure. In this dissertation, a micro size of IrOx/AgCl pH sensor was fabricated on a flexible substrate. The physical properties of the IrO x thin film was verified in the work. The different sensing capability such as the sensitivity, stability, reversibility, response time, repeatability, selectivity, and temperature dependence was then demonstrated in this work. After the different in-vitro tests, the pH sensor were embedded with our passive RFID circuitry for the in-vivo GERD diagnosis and food freshness monitoring application. Our wireless pH sensing system was able to deliver the accurate and quick pH sensing data wirelessly. In conclusion, our deformable IrOx pH electrodes have been demonstrated with the advantages of accommodating and conforming sensors in small spaces or curved surfaces. This miniature IrOx pH sensor

  7. Flexible Al-doped ZnO films grown on PET substrates using linear facing target sputtering for flexible OLEDs

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jin-A; Shin, Hyun-Su; Choi, Kwang-Hyuk; Kim, Han-Ki, E-mail: imdlhkkim@khu.ac.k [Information Materials and Device Laboratory (IMDL), Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, 1 Seocheon-dong, Yongin-si, Gyeonggi-do, 446-701 (Korea, Republic of)

    2010-11-24

    We report the characteristics of flexible Al-doped zinc oxide (AZO) films prepared by a plasma damage-free linear facing target sputtering (LFTS) system on PET substrates for use as a flexible transparent conducting electrode in flexible organic light-emitting diodes (OLEDs). The electrical, optical and structural properties of LFTS-grown flexible AZO electrodes were investigated as a function of dc power. We obtained a flexible AZO film with a sheet resistance of 39 {Omega}/{open_square} and an average transmittance of 84.86% in the visible range although it was sputtered at room temperature without activation of the Al dopant. Due to the effective confinement of the high-density plasma between the facing AZO targets, the AZO film was deposited on the PET substrate without plasma damage and substrate heating caused by bombardment of energy particles. Moreover, the flexible OLED fabricated on the AZO/PET substrate showed performance similar to the OLED fabricated on a ITO/PET substrate in spite of a lower work function. This indicates that LFTS is a promising plasma damage-free and low-temperature sputtering technique for deposition of flexible and indium-free AZO electrodes for use in cost-efficient flexible OLEDs.

  8. Nano-Floating Gate Memory Devices Composed of ZnO Thin-Film Transistors on Flexible Plastics

    Directory of Open Access Journals (Sweden)

    Park Byoungjun

    2011-01-01

    Full Text Available Abstract Nano-floating gate memory devices were fabricated on a flexible plastic substrate by a low-temperature fabrication process. The memory characteristics of ZnO-based thin-film transistors with Al nanoparticles embedded in the gate oxides were investigated in this study. Their electron mobility was found to be 0.18 cm2/V·s and their on/off ratio was in the range of 104–105. The threshold voltages of the programmed and erased states were negligibly changed up to 103 cycles. The flexibility, memory properties, and low-temperature fabrication of the nano-floating gate memory devices described herein suggest that they have potential applications for future flexible integrated electronics.

  9. Flexible photodiodes constructed with CdTe nanoparticle thin films and single ZnO nanowires on plastics.

    Science.gov (United States)

    Kwak, Kiyeol; Cho, Kyoungah; Kim, Sangsig

    2011-10-14

    We construct a flexible pn heterostructured photodiode using a CdTe nanoparticle thin film and a single ZnO nanowire (NW) on a plastic substrate. The photocurrent characteristics of the flexible photodiode are examined under illumination with 325 nm wavelength light and the photocurrent efficiencies at bias voltages of ± 2.5 V are estimated to be 8.0 and 2.1 µA W(-1) under forward and reverse bias conditions, respectively. The photocurrent generation of the pn heterostructured photodiode is dominantly associated with the transport of the photogenerated charge carriers in the single ZnO NW. Furthermore, the operations of our flexible photodiode are investigated in the upwardly and downwardly bent states, as well as in the flat state.

  10. Optimization of AZO films prepared on flexible substrates

    Indian Academy of Sciences (India)

    C C Hu; T W Lu; C Y Chou; J T Wang; H H Huang; C Y Hsu

    2014-10-01

    Transparent conductive Al2O3-doped zinc oxide (in AZO, Al2O3 content is ∼ 2 wt%) thin films are deposited on flexible polyethylene terephthalate (PET) substrates, using radio frequency (rf) magnetron sputtering. The Taguchi method with an 9 (34) orthogonal array, a signal-to-noise ratio and analysis of variance (ANOVA) was used to determine the performance characteristics of the coating operations. Using grey relational analysis, the optimization of these deposition process parameters for AZO thin films with multiple characteristics was performed. The electrical resistivity of AZO/PET films is reduced from 2.6 × 10-2 to 5.5 × 10-3 -cm and the visible range transmittance is > 83%, using the grey relational analysis. ANOVA results for the grey relational grade indicate that rf power and working pressure are the two most influential factors. The effect of the rf power (in the range from 30 to 70 W) and the argon working pressure (in the range from 0.90 to 1.1 Pa) on the morphology and optoelectronic performance of AZO films are also investigated. An analysis of the influence of the dominant parameters in the optimal design region is helpful for adjustment of the coating parameters.

  11. Graphene films printable on flexible substrates for sensor applications

    Science.gov (United States)

    Banerjee, Indrani; Faris, Tsegie; Stoeva, Zlatka; Harris, Paul G.; Chen, J.; Sharma, Ashwani K.; Ray, Asim K.

    2017-03-01

    Fifteen-layered graphene films have been successfully deposited onto flexible substrates using a commercial ink consisting of graphene particles dispersed in an acrylic polymer binder. A value of 74.9× {10}5 {{{cm}}}-2 was obtained for the density of defects, primarily located at the flake edges, from the ratio of the D and G Raman peaks located at 1345 {{{cm}}}-1 and 1575 {{{cm}}}-1 respectively. 0.5 {μ }{{m}} thick drop-cast films on interdigitated silver electrodes exhibited Ohmic conduction with a small activation energy of 12 meV over the temperature range from 260 to 330 {{K}}. The photo-thermoelectric effect is believed to be responsible for photoconduction through graphene films under illumination intensity of 10 mW m-2 at 270 {{nm}}, corresponding to the UV absorption peak. The photo-transient decay at the bias of 1 {{V}} involves two relaxation processes when the illumination is switched off and values of 8.9× {10}3 and 4.3× {10}4 {{s}} are found for the relaxation time constant using the Kohlrauch stretched exponential function analysis.

  12. Method and apparatus for assembling electric components on a flexible substrate as well as assembly of an electric component with a flexible substrate

    NARCIS (Netherlands)

    Brand, J. van den; Kusters, R.H.L.; Dietzel, A.H.

    2010-01-01

    A method is presented for assembling a component (30) with a flexible substrate (10), the component having electric contacts (31). The method comprises the steps of - placing the component (30) on a first main side (11) of the substrate, - applying a machine vision step to estimate a position of the

  13. Flexible Substrates with Polyimide Buffer Layers for Organic Light-Emitting Diodes

    Institute of Scientific and Technical Information of China (English)

    常春; 王立铎; 李扬; 段炼; 邱勇

    2004-01-01

    We report a new method to enhance the properties of the polyethyleneterephthalate (PET) substrates for flexible organic light-emitting diodes (OLEDs). By spin-coating a polyimide (PI) film between the PET and the indiumtin-oxide anode, the flexible substrate with a smooth surface, high transmission over the visible spectrum and good adhesion are achieved. We also compare the flexible OLEDs on different substrates. The diodes on the substrates with polyimide buffer layers exhibit a brightness of 7280cd/m2 at 15 V and the maximum efficiency of 2.64 cd/A.

  14. Continuous fabrication of nanostructure arrays for flexible surface enhanced Raman scattering substrate

    Science.gov (United States)

    Zhang, Chengpeng; Yi, Peiyun; Peng, Linfa; Lai, Xinmin; Chen, Jie; Huang, Meizhen; Ni, Jun

    2017-01-01

    Surface-enhanced Raman spectroscopy (SERS) has been a powerful tool for applications including single molecule detection, analytical chemistry, electrochemistry, medical diagnostics and bio-sensing. Especially, flexible SERS substrates are highly desirable for daily-life applications, such as real-time and in situ Raman detection of chemical and biological targets, which can be used onto irregular surfaces. However, it is still a major challenge to fabricate the flexible SERS substrate on large-area substrates using a facile and cost-effective technique. The roll-to-roll ultraviolet nanoimprint lithography (R2R UV-NIL) technique provides a solution for the continuous fabrication of flexible SERS substrate due to its high-speed, large-area, high-resolution and high-throughput. In this paper, we presented a facile and cost-effective method to fabricate flexible SERS substrate including the fabrication of polymer nanostructure arrays and the metallization of the polymer nanostructure arrays. The polymer nanostructure arrays were obtained by using R2R UV-NIL technique and anodic aluminum oxide (AAO) mold. The functional SERS substrates were then obtained with Au sputtering on the surface of the polymer nanostructure arrays. The obtained SERS substrates exhibit excellent SERS and flexibility performance. This research can provide a beneficial direction for the continuous production of the flexible SERS substrates. PMID:28051175

  15. Continuous fabrication of nanostructure arrays for flexible surface enhanced Raman scattering substrate

    Science.gov (United States)

    Zhang, Chengpeng; Yi, Peiyun; Peng, Linfa; Lai, Xinmin; Chen, Jie; Huang, Meizhen; Ni, Jun

    2017-01-01

    Surface-enhanced Raman spectroscopy (SERS) has been a powerful tool for applications including single molecule detection, analytical chemistry, electrochemistry, medical diagnostics and bio-sensing. Especially, flexible SERS substrates are highly desirable for daily-life applications, such as real-time and in situ Raman detection of chemical and biological targets, which can be used onto irregular surfaces. However, it is still a major challenge to fabricate the flexible SERS substrate on large-area substrates using a facile and cost-effective technique. The roll-to-roll ultraviolet nanoimprint lithography (R2R UV-NIL) technique provides a solution for the continuous fabrication of flexible SERS substrate due to its high-speed, large-area, high-resolution and high-throughput. In this paper, we presented a facile and cost-effective method to fabricate flexible SERS substrate including the fabrication of polymer nanostructure arrays and the metallization of the polymer nanostructure arrays. The polymer nanostructure arrays were obtained by using R2R UV-NIL technique and anodic aluminum oxide (AAO) mold. The functional SERS substrates were then obtained with Au sputtering on the surface of the polymer nanostructure arrays. The obtained SERS substrates exhibit excellent SERS and flexibility performance. This research can provide a beneficial direction for the continuous production of the flexible SERS substrates.

  16. Transfer of a cold atmospheric pressure plasma jet through a long flexible plastic tube

    Science.gov (United States)

    Kostov, Konstantin G.; Machida, Munemasa; Prysiazhnyi, Vadym; Honda, Roberto Y.

    2015-04-01

    This work proposes an experimental configuration for the generation of a cold atmospheric pressure plasma jet at the downstream end of a long flexible plastic tube. The device consists of a cylindrical dielectric chamber where an insulated metal rod that serves as high-voltage electrode is inserted. The chamber is connected to a long (up to 4 m) commercial flexible plastic tube, equipped with a thin floating Cu wire. The wire penetrates a few mm inside the discharge chamber, passes freely (with no special support) along the plastic tube and terminates a few millimeters before the tube end. The system is flushed with Ar and the dielectric barrier discharge (DBD) is ignited inside the dielectric chamber by a low frequency ac power supply. The gas flow is guided by the plastic tube while the metal wire, when in contact with the plasma inside the DBD reactor, acquires plasma potential. There is no discharge inside the plastic tube, however an Ar plasma jet can be extracted from the downstream tube end. The jet obtained by this method is cold enough to be put in direct contact with human skin without an electric shock. Therefore, by using this approach an Ar plasma jet can be generated at the tip of a long plastic tube far from the high-voltage discharge region, which provides the safe operation conditions and device flexibility required for medical treatment.

  17. Studies of the moisture absorption of thin carbon fiber reinforced plastic substrates for x-ray mirrors

    Science.gov (United States)

    Sugita, Satoshi; Awaki, Hisamitsu; Kurihara, Daichi; Yoshioka, Kenya; Nomura, Mizuki; Ogi, Keiji; Tomita, Yuuki; Mita, Tomoki; Kunieda, Hideyo; Matsumoto, Hironori; Miyazawa, Takuya; Mitsuishi, Ikuyuki; Iwase, Toshihiro; Maejima, Masato; Shima, Naoki; Ishikawa, Takashi; Hamada, Takayoshi; Ishida, Naoki; Akiyama, Hiromichi; Kishimoto, Kazuaki; Utsunomiya, Shin; Kamiya, Tomohiro

    2015-07-01

    We study a lightweight x-ray mirror with a carbon fiber reinforced plastic (CFRP) substrate for next-generation x-ray satellites. For tightly nested x-ray mirrors, such as those on the Suzaku and ASTRO-H telescopes, CFRP is the suitable substrate material because it has a higher strength-to-weight ratio and forming flexibility than those of metals. In flat CFRP substrate fabrication, the surface waviness has a root mean square (RMS) of ˜1 μm in the best products. The RMS approximately reaches a value consistent with the RMS of the mold used for the forming. We study the effect of moisture absorption using accelerated aging tests in three environments. The diffusivity of the CFRP substrate at 60°C and at relative humidity of 100% is ˜9.7×10-4 mm2.h-1, and the acceleration rate to the laboratory environment was 180 times higher. We also develop co-curing functional sheets with low water-vapor transmissivity on the CFRP substrate. Co-curing the sheets successfully reduced the moisture absorption rate by 440 times compared to the un-co-cured substrate. Details of the CFRP substrate fabrication and moisture absorption tests are also reported.

  18. Comparison of phenotype characteristics of rat annulus fibrosus cells cultured on flexible silicone membrane and in plastic plate

    Institute of Scientific and Technical Information of China (English)

    GUO Zhi-liang; CHENG Min; CAO Guo-yong; LI Hua-zhuang; TENG Hai-jun; ZHOU Yue

    2006-01-01

    Objective:To compare the phenotype characteristics of rat annulus fibrosus (AF) cells cultured on flexible silicone membranes and those in plastic plates. Methods :The morphology of AF cells cultured in different substrates was examined. Proteoglycan was stained by toluidine blue. Contents of collagen type I , collagen type Ⅱ and aggrecan mRNAs were determined by reverse transcription-polymerase chain reaction (RT-PCR). The expression of integrin β1 was monitored by flow cytometry. By using propidium iodide (PI), the cell cycle in AF cells was analyzed. Cell adhesion to silicone membrane was also measured. Results:The AF cells cultured on different substrates were morphologically undistinguishable.Toluidine blue staining showed that there was also no difference between AF cells cultured on these 2 substrates. They still had the same expression levels of collagen type Ⅰ , collagen type Ⅱ , aggrecan mRNAs,and integrin β1. No significant difference was observed in the distribution of the cell cycle. AF cells grew well on silicone membrane. Conclusion:AF cells cultured on flexible silicone membrane maintain the stability of phenotype and may be appropriate for further studying the metabolic responses to mechanical stimuli at the cellular level.

  19. Inverted Organic Photovoltaic Cells on Lightweight, and Flexible Metal Foil Substrates

    Science.gov (United States)

    2011-03-30

    Photovoltaic Cells on Lightweight, and Flexible Metal Foil Substrates Stephen R. Forrest Departments of EECS, Physics and Materials Science & Engineering...substrate are of interest because they can be deposited onto opaque, light-weight and possibly flexible materials allowing for use in cost-efficient...cathode, while the phthalocyanine donor absorbs longer wavelengths, and hence should optimally be adjacent to the transparent anode. Note that

  20. Solution processable colloidal nanoplates as building blocks for high-performance electronic thin films on flexible substrates.

    Science.gov (United States)

    Lin, Zhaoyang; Chen, Yu; Yin, Anxiang; He, Qiyuan; Huang, Xiaoqing; Xu, Yuxi; Liu, Yuan; Zhong, Xing; Huang, Yu; Duan, Xiangfeng

    2014-11-12

    Low-temperature solution-processed electronic materials on plastic substrates are of considerable interest for flexible electronics. Solution dispersible inorganic nanostructures (e.g., zero-dimensional (0D) quantum dots or one-dimensional (1D) nanowires) have emerged as interesting ink materials for low-temperature solution processing of electronic thin films on flexible substrates, but usually with limited performance due to the large number of grain boundaries (0D) or incomplete surface coverage (1D). Here, we report two-dimensional (2D) colloidal nanoplates of layered materials as a new ink material for solution assembly of high-performance electronic thin films. The 2D colloidal nanoplates exhibit few dangling bonds and represent an ideal geometry for the assembly of highly uniform continuous thin films with greatly reduced grain boundaries dictated by large-area conformal plane-plane contact with atomically flat/clean interfaces. It can therefore promise efficient charge transport across neighboring nanoplates and throughout the entire thin film to enable unprecedented electronic performance. We show that Bi2Se3 and Bi2Te3 nanoplates can be synthesized with well-controlled thickness (6-15 nm) and lateral dimension (0.5-3 μm) and can be used for the assembly of highly uniform continuous thin films with a full surface coverage and an excellent room temperature carrier mobility >100 cm(2)·V(-1)·s(-1), approaching that of chemical vapor deposition grown materials. Our study demonstrates a general strategy to using 2D nanoplates as a unique building block for the construction of high-performance electronic thin films on plastic substrates for future flexible electronics and optoelectronics.

  1. Generation of Cold Argon Plasma Jet at the End of Flexible Plastic Tube

    CERN Document Server

    Kostov, Konstantin G; Prysiazhnyi, Vadym

    2014-01-01

    This brief communication reports a new method for generation of cold atmospheric pressure plasma jet at the downstream end of a flexible plastic tube. The device consists of a small chamber where dielectric barrier discharge (DBD) is ignited in Argon. The discharge is driven by a conventional low frequency AC power supply. The exit of DBD reactor is connected to a commercial flexible plastic tube (up to 4 meters long) with a thin floating Cu wire inside. Under certain conditions an Ar plasma jet can be extracted from the downstream tube end and there is no discharge inside the plastic tube. The jet obtained by this method is cold enough to be put in direct contact with human skin without electric shock and can be used for medical treatment and decontamination.

  2. Low-cost rapid prototyping of flexible plastic paper based microfluidic devices

    KAUST Repository

    Fan, Yiqiang

    2013-04-01

    This research presents a novel rapid prototyping method for paper-based flexible microfluidic devices. The microchannels were fabricated using laser ablation on a piece of plastic paper (permanent paper), the dimensions of the microchannels was carefully studied for various laser powers and scanning speeds. After laser ablation of the microchannels on the plastic paper, a transparent poly (methyl methacrylate)(PMMA) film was thermally bonded to the plastic paper to enclose the channels. After connection of tubing, the device was ready to use. An example microfluidic device (droplet generator) was also fabricated using this technique. Due to the flexibility of the fabricated device, this technique can be used to fabricate 3D microfluidic devices. The fabrication process was simple and rapid without any requirement of cleanroom facilities. © 2013 IEEE.

  3. Liquid-Si Technology for High-Speed Circuits on Flexible Substrates

    NARCIS (Netherlands)

    Zhang, J.

    2015-01-01

    Recently, flexible, wearable and disposable electronics have attracted a lot of attention. Printing enables low-cost fabrication of circuits on flexible substrates. Printed organic and metal oxide thin-film transistors (TFTs) have been researched intensively due to the ease of solution-processing.

  4. Liquid-Si Technology for High-Speed Circuits on Flexible Substrates

    NARCIS (Netherlands)

    Zhang, J.

    2015-01-01

    Recently, flexible, wearable and disposable electronics have attracted a lot of attention. Printing enables low-cost fabrication of circuits on flexible substrates. Printed organic and metal oxide thin-film transistors (TFTs) have been researched intensively due to the ease of solution-processing. B

  5. Liquid-Si Technology for High-Speed Circuits on Flexible Substrates

    NARCIS (Netherlands)

    Zhang, J.

    2015-01-01

    Recently, flexible, wearable and disposable electronics have attracted a lot of attention. Printing enables low-cost fabrication of circuits on flexible substrates. Printed organic and metal oxide thin-film transistors (TFTs) have been researched intensively due to the ease of solution-processing. B

  6. Development and Plasticity of Cognitive Flexibility in Early and Middle Childhood.

    Science.gov (United States)

    Buttelmann, Frances; Karbach, Julia

    2017-01-01

    Cognitive flexibility, the ability to flexibly switch between tasks, is a core dimension of executive functions (EFs) allowing to control actions and to adapt flexibly to changing environments. It supports the management of multiple tasks, the development of novel, adaptive behavior and is associated with various life outcomes. Cognitive flexibility develops rapidly in preschool and continuously increases well into adolescence, mirroring the growth of neural networks involving the prefrontal cortex. Over the past decade, there has been increasing interest in interventions designed to improve cognitive flexibility in children in order to support the many developmental outcomes associated with cognitive flexibility. This article provides a brief review of the development and plasticity of cognitive flexibility across early and middle childhood (i.e., from preschool to elementary school age). Focusing on interventions designed to improve cognitive flexibility in typically developing children, we report evidence for significant training and transfer effects while acknowledging that current findings on transfer are heterogeneous. Finally, we introduce metacognitive training as a promising new approach to promote cognitive flexibility and to support transfer of training.

  7. Integrated isotachophoretic stacking and gel electrophoresis on a plastic substrate and variations in detection dynamic range.

    Science.gov (United States)

    Lin, Chun-Che; Hsu, Bi-Kei; Chen, Shu-Hui

    2008-03-01

    In this study, we demonstrated an integrated ITP-gel electrophoresis (GE) device on a plastic substrate, in which 50 nL of samples could be hydrodynamically or electrokinetically injected and enriched by ITP into narrow bands and then subsequently introduced into a homogeneous GE channel for separation and detection. This microchip design rendered a simple introduction scheme for creating sandwiched stacking buffer system and flexibilities in choosing separation and stacking buffers independently. We used gel sieving buffers which compositions were different from those for stacking buffers to separate DNA and protein molecules based on sizing mechanism. Compared to conventional microchip GE, the sensitivity of microchip ITP-GE was estimated to increase by one to two orders of magnitude based on the dilution factor of the injected sample and the S/N ratio detected from the electropherogram. Moreover, it is interesting to note that ITP stacking leads to a preferential enhancement for analytes with lower concentrations compared to those with higher concentrations. Therefore, a reduction in the detection dynamic range for ITP-GE was gained. We demonstrated that ITP-GE could lead to 2-4-folds of reduction in the signal dynamic range for two PCR products in a mixture. Such advantage is demonstrated to be useful for the detection of two products amplified from a multiplex PCR in which one product is poorly amplified compared to the other.

  8. Textile Pressure Sensor Made of Flexible Plastic Optical Fibers

    Directory of Open Access Journals (Sweden)

    Frank Clemens

    2008-07-01

    Full Text Available In this paper we report the successful development of pressure sensitive textile prototypes based on flexible optical fibers technology. Our approach is based on thermoplastic silicone fibers, which can be integrated into woven textiles. As soon as pressure at a certain area of the textile is applied to these fibers they change their cross section reversibly, due to their elastomeric character, and a simultaneous change in transmitted light intensity can be detected. We have successfully manufactured two different woven samples with fibers of 0.51 and 0.98 mm diameter in warp and weft direction, forming a pressure sensitive matrix. Determining their physical behavior when a force is applied shows that pressure measurements are feasible. Their usable working range is between 0 and 30 N. Small drifts in the range of 0.2 to 4.6%, over 25 load cycles, could be measured. Finally, a sensor array of 2 x 2 optical fibers was tested for sensitivity, spatial resolution and light coupling between fibers at intersections.

  9. Flexible CdTe/CdS solar cells on thin glass substrates.

    Science.gov (United States)

    Seo, Won-Oh; Kim, Donghwan; Kim, Jihyun

    2015-04-06

    We demonstrate flexible CdTe/CdS thin-film solar cells in a superstrate configuration with a cell conversion efficiency as high as 10.9%. We deposit a CdS window layer and a CdTe absorber layer on a flexible glass substrate using the chemical bath deposition method and close-spaced sublimation method, respectively. The thin and flexible glass substrates were able to tolerate a high growth temperature and post-growth processes. We repeatedly apply a strain of 0.15% to the fabricated CdTe/CdS solar cells, and this was shown to have a negligible effect on their performances. Our proposed thin films-on-compliant substrate structure, which was prepared by replacing a rigid glass with a bendable one, demonstrated flexible CdTe/CdS p-n junction thin-film solar cells without compromising the cell performance.

  10. Flexible Substrate-Based Devices for Point-of-Care Diagnostics.

    Science.gov (United States)

    Wang, ShuQi; Chinnasamy, Thiruppathiraja; Lifson, Mark A; Inci, Fatih; Demirci, Utkan

    2016-11-01

    Point-of-care (POC) diagnostics play an important role in delivering healthcare, particularly for clinical management and disease surveillance in both developed and developing countries. Currently, the majority of POC diagnostics utilize paper substrates owing to affordability, disposability, and mass production capability. Recently, flexible polymer substrates have been investigated due to their enhanced physicochemical properties, potential to be integrated into wearable devices with wireless communications for personalized health monitoring, and ability to be customized for POC diagnostics. Here, we focus on the latest advances in developing flexible substrate-based diagnostic devices, including paper and polymers, and their clinical applications.

  11. Carbon nanotube network thin-film transistors on flexible/stretchable substrates

    Energy Technology Data Exchange (ETDEWEB)

    Takei, Kuniharu; Takahashi, Toshitake; Javey, Ali

    2016-03-29

    This disclosure provides systems, methods, and apparatus for flexible thin-film transistors. In one aspect, a device includes a polymer substrate, a gate electrode disposed on the polymer substrate, a dielectric layer disposed on the gate electrode and on exposed portions of the polymer substrate, a carbon nanotube network disposed on the dielectric layer, and a source electrode and a drain electrode disposed on the carbon nanotube network.

  12. Flexible Surface Acoustic Wave Device with AlN Film on Polymer Substrate

    Directory of Open Access Journals (Sweden)

    Jian Zhou

    2012-01-01

    Full Text Available Surface acoustic wave device with c-axis-oriented aluminum nitride (AlN piezoelectric thin films on polymer substrates can be potentially used for development of flexible sensors, flexible microfluidic applications, microsystems, and lab-on-chip systems. In this work, the AlN films have been successfully deposited on polymer substrates using the DC reactive magnetron-sputtering method at room temperature, and the XRD, SEM, and AFM methods reveal that low deposition pressure is beneficial to the highly c-axis-oriented AlN film on polymer substrates. Studies toward the development of AlN thin film-based flexible surface acoustic wave devices on the polymer substrates are initiated and the experimental and simulated results demonstrate the devices showing the acoustic wave velocity of 9000–10000 m/s, which indicate the AlN lamb wave.

  13. Electromigration in Gold Films on Flexible Polyimide Substrates as a Self-healing Mechanism.

    Science.gov (United States)

    Putz, Barbara; Glushko, Oleksandr; Cordill, Megan J

    2016-01-02

    The study of electromigration (EM) in metallisations for flexible thin film systems has not been a major concern due to low applied current densities in today's flexible electronic devices. However, the trend towards smaller and more powerful devices demands increasing current densities for future applications, making EM a reliability matter. This work investigates EM in 50 nm Au thin films with a 10 nm Cr adhesion layer on a flexible polyimide substrate at high current densities. Results indicate that EM does occur and could be used as a self-healing mechanism for flexible electronics.

  14. Mechanical Characterization of Flexible and Stretchable Electronic Substrates

    NARCIS (Netherlands)

    Wang, L.

    2010-01-01

    Conventional IC packages form a rigid shell around silicon IC dies. Their purpose is to provide environmental protection, electrical interconnect and heat dissipation. Despite the fact that majority of current silicon IC′s are realized in a very thin top layer of the silicon substrate (<10µm), the t

  15. Mechanical Characterization of Flexible and Stretchable Electronic Substrates

    NARCIS (Netherlands)

    Wang, L.

    2010-01-01

    Conventional IC packages form a rigid shell around silicon IC dies. Their purpose is to provide environmental protection, electrical interconnect and heat dissipation. Despite the fact that majority of current silicon IC′s are realized in a very thin top layer of the silicon substrate (<10µm), the t

  16. A conceptual review of mate choice: stochastic demography, within-sex phenotypic plasticity, and individual flexibility.

    Science.gov (United States)

    Ah-King, Malin; Gowaty, Patricia Adair

    2016-07-01

    Mate choice hypotheses usually focus on trait variation of chosen individuals. Recently, mate choice studies have increasingly attended to the environmental circumstances affecting variation in choosers' behavior and choosers' traits. We reviewed the literature on phenotypic plasticity in mate choice with the goal of exploring whether phenotypic plasticity can be interpreted as individual flexibility in the context of the switch point theorem, SPT (Gowaty and Hubbell 2009). We found >3000 studies; 198 were empirical studies of within-sex phenotypic plasticity, and sixteen showed no evidence of mate choice plasticity. Most studies reported changes from choosy to indiscriminate behavior of subjects. Investigators attributed changes to one or more causes including operational sex ratio, adult sex ratio, potential reproductive rate, predation risk, disease risk, chooser's mating experience, chooser's age, chooser's condition, or chooser's resources. The studies together indicate that "choosiness" of potential mates is environmentally and socially labile, that is, induced - not fixed - in "the choosy sex" with results consistent with choosers' intrinsic characteristics or their ecological circumstances mattering more to mate choice than the traits of potential mates. We show that plasticity-associated variables factor into the simpler SPT variables. We propose that it is time to complete the move from questions about within-sex plasticity in the choosy sex to between- and within-individual flexibility in reproductive decision-making of both sexes simultaneously. Currently, unanswered empirical questions are about the force of alternative constraints and opportunities as inducers of individual flexibility in reproductive decision-making, and the ecological, social, and developmental sources of similarities and differences between individuals. To make progress, we need studies (1) of simultaneous and symmetric attention to individual mate preferences and subsequent

  17. Effect of Oxygen on the Structural/Electrical Properties of NIZO Films on Transparent Flexible Substrates.

    Science.gov (United States)

    Lim, Byung-Wook; Lee, Young-Jun; Kim, Joo-Hyung; Jeong, Hyeon-Taek; Ha, Tae-Won; Kim, Eun-Mi; Heo, Gi-Seok; Kim, Young-Baek; Kim, Hyeon-Ju; Lee, Ho-Saeng

    2015-10-01

    Thin film transparent oxides have attracted considerable attention over the last few decades for transparent electronic applications, such as flat panel displays, solar cells, touch-pads, and mobile devices. Metallic doped InZnO (IZO) films have been suggested for the transparent layer exhibiting semiconducting or metallic properties because of its controllable mobility and excellent electrical properties, but they show a degradation of the electrical performance under bending conditions. This study assessed Ni doped IZO (NIZO) films as a flexible transparent electrode on different flexible transparent substrates for flexible electronic applications. Thin NIZO films were deposited on cellulose, PES and glass substrates using a sputtering system with a single NIZO target (In2O3 73.8/ZnO 15.7/NiO 10.5 mol.%) at room temperature. During deposition of the NIZO films, the total flow rate of the carrier gas was maintained using a regulating system. The effects of the oxygen content in the carrier gas on the structural, electrical and optical properties of the thin films deposited on flexible substrates was characterized. The results highlight the feasibility of the transparent NIZO oxide layer on flexible substrates as a flexible electrode with a relatively high sheet resistance, which is strongly related to the crystallographic structure and oxygen content during the film deposition process.

  18. Flexible bottom-gate graphene transistors on Parylene C substrate and the effect of current annealing.

    Science.gov (United States)

    Park, Dong-Wook; Kim, Hyungsoo; Bong, Jihye; Mikael, Solomon; Kim, Tong June; Williams, Justin C; Ma, Zhenqiang

    2016-10-10

    Flexible graphene transistors built on a biocompatible Parylene C substrate would enable active circuitry to be integrated into flexible implantable biomedical devices. An annealing method to improve the performance of a flexible transistor without damaging the flexible substrate is also desirable. Here, we present a fabrication method of a flexible graphene transistor with a bottom-gate coplanar structure on a Parylene C substrate. Also, a current annealing method and its effect on the device performance have been studied. The localized heat generated by the current annealing method improves the drain current, which is attributed to the decreased contact resistance between graphene and S/D electrodes. A maximum current annealing power in the Parylene C-based graphene transistor has been extracted to provide a guideline for an appropriate current annealing. The fabricated flexible graphene transistor shows a field-effect mobility, maximum transconductance, and a Ion/Ioff ratio of 533.5 cm(2)/V s, 58.1 μS, and 1.76, respectively. The low temperature process and the current annealing method presented here would be useful to fabricate two-dimensional materials-based flexible electronics.

  19. Plasticized Polymer Interlayer for Low-Temperature Fabrication of a High-Quality Silver Nanowire-Based Flexible Transparent and Conductive Film

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Wonhee; Kang, Hong Suk; Choi, Jaeho; Lee, Hongkyung; Kim, Hee-Tak

    2017-04-18

    Silver nanowires (AgNWs) are one of the most promising materials to replace commercially available indium tin oxide in flexible transparent conductive films (TCFs); however, there are still numerous problems originating from poor AgNW junction formation and improper AgNW embedment into transparent substrates. To mitigate these problems, high-temperature processes have been adopted; however, unwanted substrate deformation prevents the use of these processes for the formation of flexible TCFs. In this work, we present a novel poly(methyl methacrylate) interlayer plasticized by dibutyl phthalate for low-temperature fabrication of AgNW-based TCFs, which does not cause any substrate deformation. By exploiting the viscoelastic properties of the plasticized interlayer near the lowered glass-transition temperature, a monolithic junction of AgNWs on the interlayer and embedment of the interconnected AgNWs into the interlayer are achieved in a single-step pressing. The resulting AgNW-TCFs are highly transparent (~92% at a wavelength of 550 nm), highly conductive (<90 Ω/sq), and environmentally and mechanically robust. Therefore, the plasticized interlayer provides a simple and effective route to fabricate high-quality AgNW-based TCFs.

  20. Solution Processable Electrochemiluminescent Ion Gels for Flexible, Low Voltage, Emissive Displays on Plastic

    Science.gov (United States)

    Moon, Hong Chul; Lodge, Timothy P.; Frisbie, C. Daniel

    2014-03-01

    We have expanded the functionality of ion gels and successfully demonstrated low voltage, flexible electrochemiluminescent (ECL) devices using patterned ECL gels. An ECL device composed of only an emissive gel and two electrodes was fabricated on an ITO-coated substrate by solution casting the ECL gel and brush-painting the top silver electrode. The device turned on at an AC voltage as low as 2.6 V (-1.3 V ~ +1.3 V) and showed a relatively rapid response (sub-ms). Also, we varied the mechanical properties of the ECL gel simply by substituting polystyrene-block-poly(methyl methacrylate)-block-polystyrene (SMS) with commercially available poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-co-HFP)), enabling the fabrication of flexible ECL devices on any target substrate by the ``cut-and-stick'' strategy. This simple, rubbery ECL gel should be attractive for flexible electronics applications such as displays on packaging.

  1. Light-emitting diodes fabricated on an electrical conducting flexible substrate

    Science.gov (United States)

    Choi, Won-Sik; Kim, Wan Jae; Park, Si-Hyun; Cho, Sung Oh; Lee, June Key; Park, Jun Beom; Ha, Jun-Seok; Chung, Tae Hoon; Jeong, Tak

    2017-01-01

    An array of InGaN-based flexible light-emitting diodes (FLEDs) was fabricated on a Ni-embedded electrical conducting flexible fabric with a full-scale 2-in. size. The FLED chip operation under current injection was realized using a single current probe as the negative electrode on the n-GaN surface; the conducting substrate was used as the positive electrode. The stability of the output power in the FLEDs was improved dramatically on the Ni-embedded conducting flexible fabric compared to that on the conventional polyimide flexible substrate. The former showed linear operation up to an input current 950 mA with no wavelength shift, whereas the latter exhibited rolling-over behavior after an input current of 200 mA.

  2. Substrate and Passivation Techniques for Flexible Amorphous Silicon-Based X-ray Detectors

    Directory of Open Access Journals (Sweden)

    Michael A. Marrs

    2016-07-01

    Full Text Available Flexible active matrix display technology has been adapted to create new flexible photo-sensing electronic devices, including flexible X-ray detectors. Monolithic integration of amorphous silicon (a-Si PIN photodiodes on a flexible substrate poses significant challenges associated with the intrinsic film stress of amorphous silicon. This paper examines how altering device structuring and diode passivation layers can greatly improve the electrical performance and the mechanical reliability of the device, thereby eliminating one of the major weaknesses of a-Si PIN diodes in comparison to alternative photodetector technology, such as organic bulk heterojunction photodiodes and amorphous selenium. A dark current of 0.5 pA/mm2 and photodiode quantum efficiency of 74% are possible with a pixelated diode structure with a silicon nitride/SU-8 bilayer passivation structure on a 20 µm-thick polyimide substrate.

  3. Substrate and Passivation Techniques for Flexible Amorphous Silicon-Based X-ray Detectors.

    Science.gov (United States)

    Marrs, Michael A; Raupp, Gregory B

    2016-07-26

    Flexible active matrix display technology has been adapted to create new flexible photo-sensing electronic devices, including flexible X-ray detectors. Monolithic integration of amorphous silicon (a-Si) PIN photodiodes on a flexible substrate poses significant challenges associated with the intrinsic film stress of amorphous silicon. This paper examines how altering device structuring and diode passivation layers can greatly improve the electrical performance and the mechanical reliability of the device, thereby eliminating one of the major weaknesses of a-Si PIN diodes in comparison to alternative photodetector technology, such as organic bulk heterojunction photodiodes and amorphous selenium. A dark current of 0.5 pA/mm² and photodiode quantum efficiency of 74% are possible with a pixelated diode structure with a silicon nitride/SU-8 bilayer passivation structure on a 20 µm-thick polyimide substrate.

  4. Titanium dioxide thin film deposited on flexible substrate by multi-jet electrospraying

    Science.gov (United States)

    Ni, Daihong; Yi, Wuming; Cao, Zhoubin; Gu, Wenhua

    2015-10-01

    Titanium dioxide thin film plays an important role in thin film solar cells, and has promising future in everyday applications including air cleaning and self-cleaning glass. With the concepts of flexible solar cells and wearable devices being more and more popular, there is increasing interest to coat titanium dioxide thin films on flexible substrates, such as aluminum foils. Many methods have been used to fabricate titanium dioxide thin films, such as dip-coating, spin coating, aerosol spray, plasma-assisted coating, electrospraying, and so on. Among them, electrospraying is especially suitable for thin film deposition on flexible substrates. This work reports fabrication of dense and uniform titanium dioxide thin films on glass as well as flexible aluminum foil using multi-jet electrospraying technique.

  5. Substrate and Passivation Techniques for Flexible Amorphous Silicon-Based X-ray Detectors

    Science.gov (United States)

    Marrs, Michael A.; Raupp, Gregory B.

    2016-01-01

    Flexible active matrix display technology has been adapted to create new flexible photo-sensing electronic devices, including flexible X-ray detectors. Monolithic integration of amorphous silicon (a-Si) PIN photodiodes on a flexible substrate poses significant challenges associated with the intrinsic film stress of amorphous silicon. This paper examines how altering device structuring and diode passivation layers can greatly improve the electrical performance and the mechanical reliability of the device, thereby eliminating one of the major weaknesses of a-Si PIN diodes in comparison to alternative photodetector technology, such as organic bulk heterojunction photodiodes and amorphous selenium. A dark current of 0.5 pA/mm2 and photodiode quantum efficiency of 74% are possible with a pixelated diode structure with a silicon nitride/SU-8 bilayer passivation structure on a 20 µm-thick polyimide substrate. PMID:27472329

  6. EBSD analysis of plastic deformation of copper foils by flexible pad laser shock forming

    Energy Technology Data Exchange (ETDEWEB)

    Nagarajan, Balasubramanian; Castagne, Sylvie [Nanyang Technological University, SIMTech-NTU Joint Laboratory (Precision Machining), Singapore (Singapore); Nanyang Technological University, School of Mechanical and Aerospace Engineering, Singapore (Singapore); Wang, Zhongke; Zheng, H.Y. [Nanyang Technological University, SIMTech-NTU Joint Laboratory (Precision Machining), Singapore (Singapore); Singapore Institute of Manufacturing Technology, Machining Technology Group, Singapore (Singapore)

    2015-11-15

    Flexible pad laser shock forming (FPLSF) is a new mold-free microforming process that induces high-strain-rate plastic deformation in thin metallic foils using laser-induced shock pressure and a hyperelastic flexible pad. This paper studies the plastic deformation behavior of copper foils formed through FPLSF by investigating surface hardness and microstructure. The microstructure of the foil surface before and after FPLSF is analyzed by electron backscatter diffraction technique using grain size distribution and grain boundary misorientation angle as analysis parameters. The surface hardness of the craters experienced a significant improvement after FPLSF; the top crater surface being harder than the bottom surface. The microstructure of the copper foil surface after FPLSF was found to be dominated by grain elongation, along with minor occurrences of subgrain formation, grain refinement, and high dislocation density regions. The results indicate that the prominent plastic deformation mechanism in FPLSF is strain hardening behavior rather than the typical adiabatic softening effect known to be occurring at high-strain-rates for processes such as electromagnetic forming, explosive forming, and laser shock forming. This significant difference in FPLSF is attributed to the concurrent reduction in plastic strain, strain rate, and the inertia effects, resulting from the FPLSF process configuration. Correspondingly, different deformation behaviors are experienced at top and bottom surfaces of the deformation craters, inducing the change in surface hardness and microstructure profiles. (orig.)

  7. A Study of GSZO TFTs for Fabrication on Plastic Substrates

    Science.gov (United States)

    2014-01-01

    of a-IGZO and a-GSZO films and TFTs to extract the effects of constituent metal cations. Comparison of the TFT performances between the a-IGZO and a...Subsequently the sample is treated in pure O2 plasma to assist in the removal of remaining organics and solvents to assure proper adhesion of the...PEN was placed on a Si substrate using adhesive to prevent stress damage to the devices. First molybdenum (Mo) was deposited onto the PEN and the

  8. A nafion coated capacitive humidity sensor on a flexible PET substrate

    KAUST Repository

    Sapsanis, Christos

    2017-03-07

    This paper reports a simple and low-cost technique for fabricating low-power capacitive humidity sensors without the use of a cleanroom environment. A maskless laser engraving system was utilized to fabricate two different gold electrode structures, interdigitated electrodes and Hilbert\\'s fifth-order fractal. The capacitive structures were implemented on a flexible PET substrate. The usage of Nafion, a well-known polymer for its hydrophilic properties as a sensing film, was attempted on the PET and outperformed the current efforts in flexible substrates. Its humidity sensing properties were evaluated in an automated gas setup with a relative humidity (RH %) ranging from 15% to 95 %.

  9. Development of high-flexible triboelectric generators using plastic metal as electrodes

    Science.gov (United States)

    Yang, Sen-Yeu; Shih, Jian-Fu; Chang, Chih-Chieh; Yang, Chii-Rong

    2017-02-01

    A triboelectric generator is a device that harvests energy through the conversion of mechanical energy into electrical energy. In this work, two polymer materials (PDMS and PET) were selected as triboelectric layers in conjunction with plastic metal (PM) films as conductive layers to produce an electrode with high flexibility. The PDMS film was fabricated with a microstructural array to enhance friction. The proposed PM material was prepared by mixing gallium-indium liquid metal and a glaze powder with excellent coating ability, extensibility, and conductivity. Results demonstrate the superior characteristics of the PM flexible electrodes, including large bending angle (≥180°), small curvature radius (≤1 mm), and stable conductivity. This PM-based triboelectric generator can achieve average output voltage of 80 V and current of 37.2 μA. The proposed flexible electrode with a PM conductive layer could be expected to make a notable contribution to the development of wearable devices.

  10. Electrohydrodynamic Direct-Write Orderly Micro/Nanofibrous Structure on Flexible Insulating Substrate

    Directory of Open Access Journals (Sweden)

    Jiang-Yi Zheng

    2014-01-01

    Full Text Available AC pulse-modulated electrohydrodynamic direct-writing (EDW was utilized to direct-write orderly micro/nanofibrous structure on the flexible insulating polyethylene terephthalate (PET substrate. During the EDW process, AC electrical field induced charges to reciprocate along the jet and decreased the charge repulsive force that applied on charged jet. Thanks to the smaller charge repulsive force, stable straight jet can be built up to direct-write orderly micro/nanofibrous structures on the insulating substrate. The minimum motion velocity required to direct-write straight line fibrous structure on insulating PET substrate was 700 mm/s. Moreover, the influences of AC voltage amplitude, frequency, and duty cycle ratio on the line width of fibrous structures were investigated. This work proposes a novel solution to overcome the inherent charge repulsion emerging on the insulating substrate, and promotes the application of EDW technology on the flexible electronics.

  11. Highly Sensitive InOx Ozone Sensing Films on Flexible Substrates

    Directory of Open Access Journals (Sweden)

    G. Kiriakidis

    2009-01-01

    Full Text Available InOx thin films with a thickness of the order of 100 nm were grown by dc magnetron sputtering on glass, Si and flexible (PET substrates. The electrical conductivity of InOx thin films exhibited a change of two orders of magnitude during photoreduction with ultraviolet light and subsequent oxidation in ozone concentrations from 2370 to 15 ppb, at room temperature. Optical transparency of over 85% for all substrates was maintained. Film structural and ozone sensing properties were analyzed. Surface morphology investigations carried out by SEM for films on PET substrates showed extended surface cracking for bending angles beyond 40∘. Optimization of growth conditions has led to films with extremely low detection levels for ozone down to 15 ppb at room temperature, demonstrating the wide prospective of utilizing these metal oxides as gas sensors on flexible substrates for a variety of automotive and air-conditioning applications.

  12. Crystalline Nanojoining Silver Nanowire Percolated Networks on Flexible Substrate.

    Science.gov (United States)

    Nian, Qiong; Saei, Mojib; Xu, Yang; Sabyasachi, Ganguli; Deng, Biwei; Chen, Yong P; Cheng, Gary J

    2015-10-27

    Optoelectronic performance of metal nanowire networks are dominated by junction microstructure and network configuration. Although metal nanowire printings, such as silver nanowires (AgNWs) or AgNWs/semiconductor oxide bilayer, have great potential to replace traditional ITO, efficient and selective nanoscale integration of nanowires is still challenging owing to high cross nanowire junction resistance. Herein, pulsed laser irradiation under controlled conditions is used to generate local crystalline nanojoining of AgNWs without affecting other regions of the network, resulting in significantly improved optoelectronic performance. The method, laser-induced plasmonic welding (LPW), can be applied to roll-to-roll printed AgNWs percolating networks on PET substrate. First principle simulations and experimental characterizations reveal the mechanism of crystalline nanojoining originated from thermal activated isolated metal atom flow over nanowire junctions. Molecular dynamic simulation results show an angle-dependent recrystallization process during LPW. The excellent optoelectronic performance of AgNW/PET has achieved Rs ∼ 5 Ω/sq at high transparency (91% @λ = 550 nm).

  13. Recent Developments of Flexible CdTe Solar Cells on Metallic Substrates: Issues and Prospects

    OpenAIRE

    Aliyu, M. M.; Islam, M.A.; Hamzah, N. R.; Karim, M. R.; M.A. Matin; Sopian, K.; Amin, N

    2012-01-01

    This study investigates the key issues in the fabrication of CdTe solar cells on metallic substrates, their trends, and characteristics as well as effects on solar cell performance. Previous research works are reviewed while the successes, potentials, and problems of such technology are highlighted. Flexible solar cells offer several advantages in terms of production, cost, and application over glass-based types. Of all the metals studied as substrates for CdTe solar cells, molybdenum appears...

  14. Development of flexible plasmonic plastic sensor using nanograting textured laminating film

    Science.gov (United States)

    Kumari, Sudha; Mohapatra, Saswat; Moirangthem, Rakesh S.

    2017-02-01

    The work presented in this paper describes the development of a cost-effective, flexible plasmonic plastic sensor using gold-coated nanograting nanoimprinted on a laminating plastic. The fabrication of plasmonic plastic sensor involved the transfer of nanograting pattern from polydimethylsiloxane (PDMS) polymer stamp to laminating plastic via thermal nanoimprint lithography, and subsequent gold film deposition. Gold-coated nanograting sample acted as a plasmonic chip, which exhibited surface plasmon resonance (SPR) mode in reflectance spectra under the white light illumination. The theoretical calculation was performed to study and analyze the excited SPR mode on the plasmonic chip. Further, the bulk refractive index sensitivity was demonstrated with respect to changing surrounding dielectric medium giving a value about 800  ±  27 nm/RIU (refractive index unit). In addition, the surface binding sensitivity upon adsorption of bovine serum albumin protein on the sensor surface was approximately 4.605 nm/(ng/mm2).We believe that our proposed low-cost plastic based plasmonic sensing device could be a potential candidate for the label-free and high-throughput screening of biological molecules.

  15. Effects of the corona pretreatment of PET substrates on the properties of flexible transparent CNT electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sang-Hoon; Kim, Bu-Jong; Park, Jin-Seok

    2014-12-01

    In this study, the effects of substrate pretreatment on the properties of carbon nanotubes (CNTs), which are used as flexible transparent electrodes, were investigated. CNTs were deposited on PET (polyethylene terephthalate) substrates using a spray coating method. Prior to the deposition of the CNTs, the PET substrates were corona-treated by varying the feeding directions of the PET substrate and the number of treatments. The variation in the surface morphology and roughness of the PET substrates due to the corona pretreatment were characterized via atomic force microscopy (AFM). The contact angles of the PET substrates were measured using polar and dispersive liquids, and the surface energies were estimated. Also, the sheet resistance of the CNTs deposited on the PET substrates was measured before and after the bending test. The experiment results provided strong evidence that the adhesive forces between the CNTs and the PET substrate can be substantially enhanced by corona pretreatment. - Highlights: • The surfaces of PET substrates have been treated via corona plasma. • The surface roughness and contact angle of PET substrate have been measured. • The effects of corona-treatment on the surface energy of PETs have been analyzed. • CNTs have been deposited on PET substrates using a spray coating method. • The variation in the sheet resistance of CNTs due to bending has been examined.

  16. Linear and nonlinear optics of pyronin Y/flexible polymer substrate for flexible organic technology: New optical approach

    Science.gov (United States)

    Yahia, I. S.; Zahran, H. Y.; Alamri, F. H.

    2017-10-01

    Pyronin Y (PY) thin films of different thicknesses were deposited on a flexible polyacetate substrate by using the spin-coating method. Pyronin Y thin films have an amorphous structure as identified by X-ray diffraction method. The linear and nonlinear optical properties of PY thin films were studied in details as a function of wavelengths. Transmittance, absorbance and reflectance spectra of pyronin Y thin films were recorded in the wavelengths range from 300 to 2500 nm. The refractive and absorption indices have been computed from Fresnel's equation. The optical band gaps were calculated for the studied PY thin film of thicknesses 205, 140 and 95 nm. Both direct and indirect gaps were computed as a function of PY of different thicknesses. The dielectric constant, dielectric loss and dissipation factor were investigated for the studied material. Spectrophotometric data was used to determine the nonlinear refractive index and the third nonlinear optical susceptibility. Pyronin Y thin films/polymer flexible substrate can be used in many applications such as flexible optoelectronic/electronic devices and for nonlinear optics with specified band gap.

  17. A gold surface plasmon enhanced mesoporous titanium dioxide photoelectrode for the plastic-based flexible dye-sensitized solar cells

    Science.gov (United States)

    Chen, Hsin-Wei; Hong, Chen-Yu; Kung, Chung-Wei; Mou, Chung-Yuan; Wu, Kevin C.-W.; Ho, Kuo-Chuan

    2015-08-01

    The gold nanoparticles inlaid mesoporous titania nanoparticles (Au@MTNs) thin films are fabricated on a conductive plastic substrate by using a low-temperature electrophoretic deposition (EPD) process followed by a compression post-treatment. The obtained Au@MTNs electrode exhibits an excellent light trapping because of the formation of surface plasmons on the Au nanoparticles (NPs). The flexible Au@MTNs electrodes are applied for the photoanodes in all-plastic-based dye-sensitized solar cells (DSSCs). The Au@MTNs photoanodes containing various wt% of Au NPs are prepared in order to optimize the performance of the DSSCs. When 0.8 wt% of Au NPs is used in the Au@MTNs photoanode, a power conversion efficiency (η) of 5.62% is achieved under the illumination of 100 mW cm-2, which exhibits a 14% increase compared to the DSSC fabricated with pure a titanium dioxide (TiO2) photoanode (4.93%); this enhancement is attributed to the plasmonic light trapping provided by the Au NPs.

  18. Vibration Control of Flexible Mode for a Beam-Type Substrate Transport Robot

    Directory of Open Access Journals (Sweden)

    Cheol Hoon Park

    2013-07-01

    Full Text Available Beam‐type substrate transport robots are widely used to handle substrates, especially in the solar cell manufacturing process. To reduce the takt time and increase productivity, accurate position control becomes increasingly important as the size of the substrate increases. However, the vibration caused by the flexible forks in beam‐type robots interferes with accurate positioning, which results in long takt times in the manufacturing process. To minimize the vibration and transport substrates on the fork as fast as possible, the trajectories should be prevented from exciting the flexible modes of the forks. For this purpose, a fifth‐order polynomial trajectory generator and input shaping were incorporated into the controller of the beam‐type robot in this study. The flexible modes of the forks were identified by measuring the frequency response function (FRF, and the input shaping was designed so as not to excite the flexible modes. The controller was implemented by using MATLAB/xPC Target. In this paper, the design procedure of input shaping and its effectiveness for vibration attenuation in both “no load” and “load” cases is presented.

  19. Exploring the magnetization dynamics of NiFe/Pt multilayers in flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Corrêa, M.A., E-mail: marciocorrea@dfte.ufrn.br [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Dutra, R.; Marcondes, T.L. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150, Urca, 22290-180 Rio de Janeiro, RJ (Brazil); Mori, T.J.A. [Laboratório Nacional de Luz Síncrotron, Rua Giuseppe Máximo Scolfaro, 1000, Guará, 13083-100 Campinas, SP (Brazil); Bohn, F. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Sommer, R.L. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150, Urca, 22290-180 Rio de Janeiro, RJ (Brazil)

    2016-09-15

    Highlights: • Magnetic properties of multilayers grown onto flexible substrates were investigated. • Experimental and theoretical magnetization dynamics results are presented. • The flexible substrates become promising candidate for rf-frequency devices. - Abstract: We investigate the structural and magnetic properties, and the magnetization dynamics in Ni{sub 81}Fe{sub 19}/Pt multilayer systems grown onto rigid and flexible substrates. The structural characterization shows evidence of a superlattice behavior, while the quasi-static magnetization characterization reveal a weak magnetic anisotropy induced in the multilayers. The magnetization dynamics is investigated through the magnetoimpedance effect. We employ a theoretical approach to describe the experimental magnetoimpedance effect and verify the influence of the effective damping parameter on the magnetization dynamics. Experimental data and theoretical results are in agreement and suggest that the multilayers present high effective damping parameter. Moreover, our experiments raise an interesting issue on the possibility of achieving considerable MI% values, even for systems with weak magnetic anisotropy and high damping parameter grown onto flexible substrates.

  20. Fabrication of ferroelectric polymer nanostructures on flexible substrates by soft-mold reverse nanoimprint lithography.

    Science.gov (United States)

    Song, Jingfeng; Lu, Haidong; Li, Shumin; Tan, Li; Gruverman, Alexei; Ducharme, Stephen

    2016-01-08

    Conventional nanoimprint lithography with expensive rigid molds is used to pattern ferroelectric polymer nanostructures on hard substrate for use in, e.g., organic electronics. The main innovation here is the use of inexpensive soft polycarbonate molds derived from recordable DVDs and reverse nanoimprint lithography at low pressure, which is compatible with flexible substrates. This approach was implemented to produce regular stripe arrays with a spacing of 700 nm from vinylidene fluoride co trifluoroethylene ferroelectric copolymer on flexible polyethylene terephthalate substrates. The nanostructures have very stable and switchable piezoelectric response and good crystallinity, and are highly promising for use in organic electronics enhanced or complemented by the unique properties of the ferroelectric polymer, such as bistable polarization, piezoelectric response, pyroelectric response, or electrocaloric function. The soft-mold reverse nanoimprint lithography also leaves little or no residual layer, affording good isolation of the nanostructures. This approach reduces the cost and facilitates large-area, high-throughput production of isolated functional polymer nanostructures on flexible substrates for the increasing application of ferroelectric polymers in flexible electronics.

  1. Vibration Control of Flexible Mode for a Beam-Type Substrate Transport Robot

    Directory of Open Access Journals (Sweden)

    Cheol Hoon Park

    2013-07-01

    Full Text Available Beam-type substrate transport robots are widely used to handle substrates, especially in the solar cell manufacturing process. To reduce the takt time and increase productivity, accurate position control becomes increasingly important as the size of the substrate increases. However, the vibration caused by the flexible forks in beam-type robots interferes with accurate positioning, which results in long takt times in the manufacturing process. To minimize the vibration and transport substrates on the fork as fast as possible, the trajectories should be prevented from exciting the flexible modes of the forks. For this purpose, a fifth-order polynomial trajectory generator and input shaping were incorporated into the controller of the beam-type robot in this study. The flexible modes of the forks were identified by measuring the frequency response function (FRF, and the input shaping was designed so as not to excite the flexible modes. The controller was implemented by using MATLAB/xPC Target. In this paper, the design procedure of input shaping and its effectiveness for vibration attenuation in both “no load” and “load” cases is presented.

  2. Electron Beam Evaporated TiO2 Layer for High Efficiency Planar Perovskite Solar Cells on Flexible Polyethylene Terephthalate Substrates

    KAUST Repository

    Qiu, Weiming

    2015-09-30

    The TiO2 layer made by electron beam (e-beam) induced evaporation is demonstrated as electron transport layer (ETL) in high efficiency planar junction perovskite solar cells. The temperature of the substrate and the thickness of the TiO2 layer can be easily controlled with this e-beam induced evaporation method, which enables the usage of different types of substrates. Here, Perovskite solar cells based on CH3NH3PbI3-xClx achieve power conversion efficiencies of 14.6% on glass and 13.5% on flexible plastic substrates. The relationship between the TiO2 layer thickness and the perovskite morphology is studied with scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray photoelectron spectroscopy (XPS). Our results indicate that pinholes in thin TiO2 layer lead to pinholes in the perovskite layer. By optimizing the TiO2 thickness, perovskite layers with substantially increased surface coverage and reduced pinhole areas are fabricated, increasing overall device performance.

  3. Exploration of CIGAS Alloy System for Thin-Film Photovoltaics on Novel Lightweight and Flexible Substrates

    Science.gov (United States)

    Woods, Lawrence M.; Kalla, Ajay; Ribelin, Rosine

    2007-01-01

    Thin-film photovoltaics (TFPV) on lightweight and flexible substrates offer the potential for very high solar array specific power (W/kg). ITN Energy Systems, Inc. (ITN) is developing flexible TFPV blanket technology that has potential for specific power greater than 2000 W/kg (including space coatings) that could result in solar array specific power between 150 and 500 W/kg, depending on array size, when mated with mechanical support structures specifically designed to take advantage of the lightweight and flexible substrates.(1) This level of specific power would far exceed the current state of the art for spacecraft PV power generation, and meet the needs for future spacecraft missions.(2) Furthermore the high specific power would also enable unmanned aircraft applications and balloon or high-altitude airship (HAA) applications, in addition to modular and quick deploying tents for surface assets or lunar base power, as a result of the high power density (W/sq m) and ability to be integrated into the balloon, HAA or tent fabric. ITN plans to achieve the high specific power by developing single-junction and two-terminal monolithic tandem-junction PV cells using thin-films of high-efficiency and radiation resistant CuInSe2 (CIS) partnered with bandgap-tunable CIS-alloys with Ga (CIGS) or Al (CIAS) on novel lightweight and flexible substrates. Of the various thin-film technologies, single-junction and radiation resistant CIS and associated alloys with gallium, aluminum and sulfur have achieved the highest levels of TFPV device performance, with the best efficiency reaching 19.5% under AM1.5 illumination conditions and on thick glass substrates.(3) Thus, it is anticipated that single- and tandem-junction devices with flexible substrates and based on CIS and related alloys will achieve the highest levels of thin-film space and HAA solar array performance.

  4. Experimental investigation on photoelectric properties of ZAO thin film deposited on flexible substrate by magnetron sputtering

    Science.gov (United States)

    Hao, Ming; Liu, Kun; Liu, Xinghua; Wang, Dongyang; Ba, Dechun; Xie, Yuanhua; Du, Guangyu; Ba, Yaoshuai

    2016-12-01

    Transparent conductive ZAO (Zinc Aluminum Oxide) films on flexible substrates have a great potential for low-cost mass-production solar cells. ZAO thin films were achieved on flexible PET (polyethylene terephthalate) substrates by RF magnetron sputtering technology. The surface morphology and element content, the transmittance and the sheet resistance of the films were measured to determine the optical process parameters. The results show that the ZAO thin film shows the best parameters in terms of photoelectric performance including sputtering power, working pressure, sputtering time, substrate temperature (100 W, 1.5 Pa, 60 min, 125 °C). The sheet resistance of 510 Ω and transmittance in visible region of 92% were obtained after characterization. Surface morphology was uniform and compact with a good crystal grain.

  5. Growth of gallium nitride and indium nitride nanowires on conductive and flexible carbon cloth substrates.

    Science.gov (United States)

    Yang, Yi; Ling, Yichuan; Wang, Gongming; Lu, Xihong; Tong, Yexiang; Li, Yat

    2013-03-07

    We report a general strategy for synthesis of gallium nitride (GaN) and indium nitride (InN) nanowires on conductive and flexible carbon cloth substrates. GaN and InN nanowires were prepared via a nanocluster-mediated growth method using a home built chemical vapor deposition (CVD) system with Ga and In metals as group III precursors and ammonia as a group V precursor. Electron microscopy studies reveal that the group III-nitride nanowires are single crystalline wurtzite structures. The morphology, density and growth mechanism of these nanowires are determined by the growth temperature. Importantly, a photoelectrode fabricated by contacting the GaN nanowires through a carbon cloth substrate shows pronounced photoactivity for photoelectrochemical water oxidation. The ability to synthesize group III-nitride nanowires on conductive and flexible substrates should open up new opportunities for nanoscale photonic, electronic and electrochemical devices.

  6. Preparation and characterization of polyurethane plasticizer for flexible packaging applications: Natural oils affirmed access

    Directory of Open Access Journals (Sweden)

    Mohammed A. Mekewi

    2017-03-01

    Full Text Available Developing bio-renewable feedstock for polyurethane (PU manufacturing and polymer industry as a whole has become highly desirable for both economic and environmental reasons. In this work castor oil (CO and palm olein (PO polyols were synthesized and partially used as renewable feedstock for the manufacturing of polyurethane plasticizing resin for printing ink applications. The chemical structure of the prepared polyols and polyurethanes were characterized using IR spectra and GPC and their solubility in common solvents was tested. As well, properties such as flexibility, mechanical properties, optical properties, heat seal and freeze resistance of these prepared printing inks were determined. The results indicated that the prepared printing inks from 50% synthesized polyurethane have high thermal stability, adhesion and excellent freeze resistance. The net technical properties of the new ink formulations are relatively comparable to the printing ink prepared from standard polyurethane plasticizer.

  7. Large-area, uniform white light LED source on a flexible substrate.

    Science.gov (United States)

    Sher, Chin-Wei; Chen, Kuo-Ju; Lin, Chien-Chung; Han, Hau-Vei; Lin, Huang-Yu; Tu, Zong-Yi; Tu, Hsien-Hao; Honjo, Keiji; Jiang, Hsin-Yi; Ou, Sin-Liang; Horng, Ray-Hua; Li, Xiuling; Fu, Chien-Chung; Kuo, Hao-Chung

    2015-09-21

    This study demonstrates the flexible white LED structure with high lumen efficiency and uniform optical performance for neutral white and warm white CCT. Flip-chip LEDs were attached on a polyimide substrate with copper strips as electrical and thermal conduction paths. Yellow phosphors are mixed with polydimenthysiloxane (PDMS) to provide mechanical support and flexibility. The light efficiency of this device can reach 120 lm/W and 85% of light output uniformity of the emission area can be achieved. Moreover, the optical simulation is employed to evaluate various designs of this flexible film in order to obtain uniform output. Both the pitch between the individual devices and the thickness of the phosphor film are calculated for optimization purpose. This flexible white LED with high lumen efficiency and good reliability is suitable for the large area fixture in the general lighting applications.

  8. Highly flexible InSnO electrodes on thin colourless polyimide substrate for high-performance flexible CH3NH3PbI3 perovskite solar cells

    Science.gov (United States)

    Park, Jeong-Il; Heo, Jin Hyuck; Park, Sung-Hyun; Hong, Ki Il; Jeong, Hak Gee; Im, Sang Hyuk; Kim, Han-Ki

    2017-02-01

    We fabricated high-performance flexible CH3NH3PbI3 (MAPbI3) perovskite solar cells with a power conversion efficiency of 15.5% on roll-to-roll sputtered ITO films on 60 μm-thick colourless polyimide (CPI) substrate. Due to the thermal stability of the CPI substrate, an ITO/CPI sample subjected to rapid thermal annealing at 300 °C showed a low sheet resistance of 57.8 Ω/square and high transmittance of 83.6%, which are better values than those of an ITO/PET sample. Outer and inner bending tests demonstrated that the mechanical flexibility of the ITO/CPI was superior to that of the conventional ITO/PET sample owing to the thinness of the CPI substrate. In addition, due to its good mechanical flexibility, the ITO/CPI showed no change in resistance after 10,000 cycle outer and inner dynamic fatigue tests. Flexible perovskite solar cells with the structure of Au/PTAA/MAPbI3/ZnO/ITO/CPI showed a high power conversion efficiency of 15.5%. The successful operation of these flexible perovskite solar cells on ITO/CPI substrate indicated that the ITO film on thermally stable CPI substrate is a promising of flexible substrate for high-temperature processing, a finding likely to advance the commercialization of cost-efficient flexible perovskite solar cells.

  9. Reduced migration from flexible poly(vinyl chloride) of a plasticizer containing beta-cyclodextrin derivative.

    Science.gov (United States)

    Yu, Ong Yong; Chung, Jae Woo; Kwak, Seung-Yeop

    2008-10-01

    The migration of endocrine-disrupting di-(2-ethylhexyl) phthalate (DEHP) poses a serious threat to public health and the environment. In this study, we successfully prepared a plasticizerwith reduced DEHP migration by directly incorporating 2,3,6-per-O-benzoyl-beta-cyclodextrin (Bz-beta-CD) into DEHP. Bz-beta-CD was prepared by esterification between the hydroxyl groups of beta-CD and benzoyl chloride. The presence of this cyclodextrin is expected to facilitate formation of stable complexes through pi-pi association with DEHP molecules. The flexible PVC was prepared with a gelation-fusion process that uses the prepared migration-resistant plasticizer, and its properties (flexibility, thermal stability, and clarity) were evaluated by carrying out DSC and tensile testing, TGA, and haze testing, respectively. No significant changes in the physical properties of the flexible PVC were observed when Bz-beta-CD was added. DEHP migration tests were carried out for the flexible PVC according to the ISO 3826:1993(E) test method, and the quantity of migrated DEHP was then determined with UV-vis spectroscopy. It was found that the addition of Bz-beta-CD decreases the levels of DEHP migration from the flexible PVC samples by almost 40%. We investigated the molecular interaction between Bz-beta-CD and DEHP using molecular mechanics simulations, and we conclude that this reduction in DEHP migration is due to the formation of stabilized pi-pi attractive association and inclusion complexes of Bz-beta-CD and DEHP in flexible PVC.

  10. Chemical Vapour Deposition of Graphene with Re-useable Pt and Cu substrates for Flexible Electronics

    Science.gov (United States)

    Karamat, Shumaila; Sonusen, Selda; Celik, Umit; Uysalli, Yigit; Oral, Ahmet

    2015-03-01

    Graphene has gained the attention of scientific world due to its outstanding physical properties. The future demand of flexible electronics such as solar cells, light emitting diodes, photo-detectors and touch screen technology requires more exploration of graphene properties on flexible substrates. The most interesting application of graphene is in organic light emitting diodes (OLED) where efforts are in progress to replace brittle indium tin oxide (ITO) electrode with a flexible graphene electrode because ITO raw materials are becoming increasingly expensive, and its brittle nature makes it unsuitable for flexible devices. In this work, we grow graphene on Pt and Cu substrates using chemical vapour deposition (CVD) and transferred it to a polymer material (PVA) using lamination technique. We used hydrogen bubbling method for separating graphene from Pt and Cu catalyst to reuse the substrates many times. After successful transfer of graphene on polymer samples, we checked the resistivity values of the graphene sheet which varies with growth conditions. Furthermore, Raman, atomic force microscopy (AFM), I-V and Force-displacement measurements will be presented for these samples.

  11. Highly efficient single-junction GaAs thin-film solar cell on flexible substrate

    Science.gov (United States)

    Moon, Sunghyun; Kim, Kangho; Kim, Youngjo; Heo, Junseok; Lee, Jaejin

    2016-07-01

    There has been much interest in developing a thin-film solar cell because it is lightweight and flexible. The GaAs thin-film solar cell is a top contender in the thin-film solar cell market in that it has a high power conversion efficiency (PCE) compared to that of other thin-film solar cells. There are two common structures for the GaAs solar cell: n (emitter)-on-p (base) and p-on-n. The former performs better due to its high collection efficiency because the electron diffusion length of the p-type base region is much longer than the hole diffusion length of the n-type base region. However, it has been limited to fabricate highly efficient n-on-p single-junction GaAs thin film solar cell on a flexible substrate due to technical obstacles. We investigated a simple and fast epitaxial lift-off (ELO) method that uses a stress originating from a Cr/Au bilayer on a 125-μm-thick flexible substrate. A metal combination of AuBe/Pt/Au is employed as a new p-type ohmic contact with which an n-on-p single-junction GaAs thin-film solar cell on flexible substrate was successfully fabricated. The PCE of the fabricated single-junction GaAs thin-film solar cells reached 22.08% under air mass 1.5 global illumination.

  12. Mechanically robust 39 GHz cut-off frequency graphene field effect transistors on flexible substrates.

    Science.gov (United States)

    Wei, Wei; Pallecchi, Emiliano; Haque, Samiul; Borini, Stefano; Avramovic, Vanessa; Centeno, Alba; Amaia, Zurutuza; Happy, Henri

    2016-08-07

    Graphene has been regarded as a promising candidate channel material for flexible devices operating at radio-frequency (RF). In this work we fabricated and fully characterized double bottom-gate graphene field effect transistors on flexible polymer substrates for high frequency applications. We report a record high as-measured current gain cut-off frequency (ft) of 39 GHz. The corresponding maximum oscillation frequency (fmax) is 13.5 GHz. These state of the art high frequency performances are stable against bending, with a typical variation of around 10%, for a bending radius of up to 12 mm. To demonstrate the reliability of our devices, we performed a fatigue stress test for RF-GFETs which were dynamically bend tested 1000 times at 1 Hz. The devices are mechanically robust, and performances are stable with typical variations of 15%. Finally we investigate thermal dissipation, which is a critical parameter for flexible electronics. We show that at the optimum polarization the normalized power dissipated by the GFETs is about 0.35 mW μm(-2) and that the substrate temperature is around 200 degree centigrade. At a higher power, irreversible degradations of the performances are observed. Our study on state of the art flexible GFETs demonstrates mechanical robustness and stability upon heating, two important elements to assess the potential of GFETs for flexible electronics.

  13. Rapid Low-Temperature 3D Integration of Silicon Nanowires on Flexible Substrates.

    Science.gov (United States)

    Kim, Yoonkap; Kim, Han-Jung; Kim, Jae-Hyun; Choi, Dae-Geun; Choi, Jun-Hyuk; Jung, Joo-Yun; Jeon, Sohee; Lee, Eung-Sug; Jeong, Jun-Ho; Lee, Jihye

    2015-08-26

    The vertical integration of 1D nanostructures onto the 2D substrates has the potential to offer significant performance gains to flexible electronic devices due to high integration density, large surface area, and improved light absorption and trapping. A simple, rapid, and low temperature transfer bonding method has been developed for this purpose. Ultrasonic vibration is used to achieve a low temperature bonding within a few seconds, resulting in a polymer-matrix-free, electrically conducting vertical assembly of silicon nanowires (SiNWs) with a graphene/PET substrate. The microscopic structure, and mechanical and electrical characteristics of the interface between the transferred SiNW array and graphene layer are subsequently investigated, revealing that this creates a mechanically robust and electrically Ohmic contact. This newly developed ultrasonic transfer bonding technique is also found to be readily adaptable for diverse substrates of both metal and polymer. It is therefore considered as a valuable technique for integrating 1D vertical nanostructures onto the 2D flexible substrates for flexible photovoltaics, energy storage, and water splitting systems.

  14. Flexible amorphous oxide thin-film transistors on polyimide substrate for AMOLED

    Science.gov (United States)

    Xu, Zhiping; Li, Min; Xu, Miao; Zou, Jianhua; Gao, Zhuo; Pang, Jiawei; Guo, Ying; Zhou, Lei; Wang, Chunfu; Fu, Dong; Peng, Junbiao; Wang, Lei; Cao, Yong

    2014-10-01

    We report a flexible amorphous Lanthanide doped In-Zn-O (IZO) thin-film transistor (TFT) backplane on polyimide (PI) substrate. In order to de-bond the PI film from the glass carrier easily after the flexible AMOLED process, a special inorganic film is deposited on the glass before the PI film is coated. The TFT exhibited a field-effect mobility of 6.97 cm2V-1 s-1, a subthreshold swing of 0.248 V dec-1, and an Ion/Ioff ratio of 5.19×107, which is sufficient to drive the OLEDs.

  15. Effects of device size and material on the bending performance of resistive-switching memory devices fabricated on flexible substrates

    Science.gov (United States)

    Lee, Won-Ho; Yoon, Sung-Min

    2017-05-01

    The resistive change memory (RCM) devices using amorphous In-Ga-Zn-O (IGZO) and microcrystalline Al-doped ZnO (AZO) thin films were fabricated on plastic substrates and characterized for flexible electronic applications. The device cell sizes were varied to 25 × 25, 50 × 50, 100 × 100, and 200 × 200 μm2 to examine the effects of cell size on the resistive-switching (RS) behaviors at a flat state and under bending conditions. First, it was found that the high-resistance state programmed currents markedly increased with the increase in the cell size. Second, while the AZO RCM devices did not exhibit RESET operations at a curvature radius smaller than 8.0 mm, the IGZO RCM devices showed sound RS behaviors even at a curvature radius of 4.5 mm. Third, for the IGZO RCM devices with the cell size bigger than 100 × 100 μm2, the RESET operation could not be performed at a curvature radius smaller than 6.5 mm. Thus, it was elucidated that the RS characteristics of the flexible RCM devices using oxide semiconductor thin films were closely related to the types of RS materials and the cell size of the device.

  16. Intraspecific variation in social organization by genetic variation, developmental plasticity, social flexibility or entirely extrinsic factors.

    Science.gov (United States)

    Schradin, Carsten

    2013-05-19

    Previously, it was widely believed that each species has a specific social organization, but we know now that many species show intraspecific variation in their social organization. Four different processes can lead to intraspecific variation in social organization: (i) genetic variation between individuals owing to local adaptation (between populations) or evolutionarily stable strategies within populations; (ii) developmental plasticity evolved in long-term (more than one generation) unpredictable and short-term (one generation) predictable environments, which is mediated by organizational physiological effects during early ontogeny; (iii) social flexibility evolved in highly unpredictable environments, which is mediated by activational physiological effects in adults; (iv) entirely extrinsic factors such as the death of a dominant breeder. Variation in social behaviour occurs between individuals in the case of genetic variation and developmental plasticity, but within individuals in the case of social flexibility. It is important to study intraspecific variation in social organization to understand the social systems of species because it reveals the mechanisms by which species can adapt to changing environments, offers a useful tool to study the ultimate and proximate causes of sociality, and is an interesting phenomenon by itself that needs scientific explanation.

  17. Development and application of flexible substrate sensors in instantaneous heat flux measurement

    Institute of Scientific and Technical Information of China (English)

    XU Duo; GU JiaHua; WU Song

    2009-01-01

    A new type of sensor with the flexible substrate is introduced.It is applicable in measuring instanta-neous heat flux on the model surface in a hypersonic shock tunnel.The working principle,structure and manufacture process of the sensor are presented.The substrate thickness and the dynamic re-sponse parameter of the sensor are calculated.Because this sensor was successfully used in meas-uring the instantaneous heat flux on the surface of a flat plate in a detonation-driven shock tunnel,it may be effective in measuring instantaneous heat flux on the model surface.

  18. Tunable diffraction grating in flexible substrate by UV-nanoimprint lithography

    Science.gov (United States)

    Hamouda, F.; Aassime, A.; Bertin, H.; Gogol, P.; Bartenlian, B.; Dagens, B.

    2017-02-01

    The fabrication of flexible advanced devices is a very important issue that requires the hybrid integration of different nanostructured materials. In this work, we report on a new molding technique based on an improved hard UV-nanoimprint lithography process (hard UV-NIL) using a poly(dimethylsiloxane) (PDMS) film. The large-scale integration of a high-quality nanostructured gold pattern in PDMS is made possible with the use of an inorganic sacrificial layer soluble in hydrogen peroxide. A tunable diffraction gold stripe grating has been fabricated by transferring a 1 cm2 stripe grating from a rigid silicon substrate to a flexible PDMS substrate. As a result, we successfully demonstrate diffraction grating optical tunability when mechanical tension is applied.

  19. Fabrication and characterization of all-polymer, transparent ferroelectric capacitors on flexible substrates

    KAUST Repository

    Khan, Mohammad A.

    2011-12-01

    All-polymer, transparent ferroelectric devices, based on the functional polymer poly(vinylidene fluoride trifluoroethylene) [P(VDF-TrFE)], have been fabricated on flexible substrates. The performance of the all-polymer devices was studied and compared to devices with metal electrodes. Specifically, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) [PEDOT:PSS] and platinum (Pt) electrode effects on the morphology, crystallinity and orientation of P(VDF-TrFE) films were investigated. The devices with PEDOT:PSS electrodes showed similar hysteresis and switching current response compared to Pt electrodes but with tremendously improved fatigue performance. Further, the devices with PEDOT:PSS electrodes showed lower coercive field and better fatigue performance than values reported for other polymer electrodes used with P(VDF-TrFE) on flexible substrates. © 2011 Elsevier B.V. All rights reserved.

  20. Synthesis of Cu doped ZnS nanostructures on flexible substrate using low cost chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Nitin, E-mail: nitinmishra97@gmail.com; Purohit, L. P., E-mail: lppurohit@gmail.com [Gurukula Kangari University, Haridwar UK (India); Goswami, Y. C., E-mail: y-goswami@yahoo.com [ITM University, Turari, Gwalior, MP (India)

    2015-08-28

    Flexible electronics is one of the emerging area of this era. In this paper we have reported synthesis of Cu doped Zinc sulphide nanostructures on filter paper flexible substrates. Zinc chloride and Thio urea were used as a precursor for Zinc and Sulphur. The structures were characterized by XRD, FE-SEM and UV visible spectrometer. All the peaks identified for cubic structure of ZnS. Appearance of small Cu peaks indicates incorporation of Cu into ZnS lattice. Zns nanostructures assembled as nanobelts and nanofibers as shown in FE-SEM micrographs. Compound Structures provide the reasonable electrical conductivity on filter paper. Absorption in UV region makes them suitable for flexible electronic devices.

  1. Recent Developments of Flexible CdTe Solar Cells on Metallic Substrates: Issues and Prospects

    Directory of Open Access Journals (Sweden)

    M. M. Aliyu

    2012-01-01

    Full Text Available This study investigates the key issues in the fabrication of CdTe solar cells on metallic substrates, their trends, and characteristics as well as effects on solar cell performance. Previous research works are reviewed while the successes, potentials, and problems of such technology are highlighted. Flexible solar cells offer several advantages in terms of production, cost, and application over glass-based types. Of all the metals studied as substrates for CdTe solar cells, molybdenum appears the most favorable candidate, while close spaced sublimation (CSS, electrodeposition (ED, magnetic sputtering (MS, and high vacuum thermal evaporation (HVE have been found to be most common deposition technologies used for CdTe on metal foils. The advantages of these techniques include large grain size (CSS, ease of constituent control (ED, high material incorporation (MS, and low temperature process (MS, HVE, ED. These invert-structured thin film CdTe solar cells, like their superstrate counterparts, suffer from problems of poor ohmic contact at the back electrode. Thus similar strategies are applied to minimize this problem. Despite the challenges faced by flexible structures, efficiencies of up to 13.8% and 7.8% have been achieved in superstrate and substrate cell, respectively. Based on these analyses, new strategies have been proposed for obtaining cheaper, more efficient, and viable flexible CdTe solar cells of the future.

  2. In Tube Integrated Electronic Nose System on a Flexible Polymer Substrate

    Directory of Open Access Journals (Sweden)

    Gerhard Tröster

    2012-10-01

    Full Text Available The fabrication of electronic devices, such as gas sensors on flexible polymer substrates, enables the use of electronics in applications where conventional devices on stiff substrates could not be used. We demonstrate the development of a new intra-tube electronic-nose (e-nose gas sensor device with multiple sensors fabricated and integrated on a flexible substrate. For this purpose, we developed a new method of fabricating a sensor array of four gas sensors on a flexible polymer substrate. The method allowed the use of lithography techniques to pattern different polymers with a broad range of solubility parameters. Conductive polymer composites were used as a gas sensitive layer due to the high stretchability of the material. Each of the 30 e-nose devices on one substrate was designed to fit on a polymer strip with a width of 2 mm. A single e-nose strip was successfully integrated into the inlet tube of a gas-measurement apparatus with an inner-tube diameter of 3 mm. Using the e-nose, we were able to differentiate between four different volatile solvent vapors. The tube-integrated e-nose outperformed a chamber-integrated e-nose of the same type in terms of response time and flow-rate influences. The sensor array inside the tube showed a faster response time and detected short pulses of analyte exposure compared to the same sensor array outside of the tube. We measured gas flow rates from 1,000 to 30 sccm without significant changes in sensor performance using this intra-tube e-nose prototype. The tube could be bent to radii < 15 mm with a sensor performance similar to an unbent sensor.

  3. In tube integrated electronic nose system on a flexible polymer substrate.

    Science.gov (United States)

    Kinkeldei, Thomas; Zysset, Christoph; Münzenrieder, Niko; Petti, Luisa; Tröster, Gerhard

    2012-10-12

    The fabrication of electronic devices, such as gas sensors on flexible polymer substrates, enables the use of electronics in applications where conventional devices on stiff substrates could not be used. We demonstrate the development of a new intra-tube electronic-nose (e-nose) gas sensor device with multiple sensors fabricated and integrated on a flexible substrate. For this purpose, we developed a new method of fabricating a sensor array of four gas sensors on a flexible polymer substrate. The method allowed the use of lithography techniques to pattern different polymers with a broad range of solubility parameters. Conductive polymer composites were used as a gas sensitive layer due to the high stretchability of the material. Each of the 30 e-nose devices on one substrate was designed to fit on a polymer strip with a width of 2 mm. A single e-nose strip was successfully integrated into the inlet tube of a gas-measurement apparatus with an inner-tube diameter of 3 mm. Using the e-nose, we were able to differentiate between four different volatile solvent vapors. The tube-integrated e-nose outperformed a chamber-integrated e-nose of the same type in terms of response time and flow-rate influences. The sensor array inside the tube showed a faster response time and detected short pulses of analyte exposure compared to the same sensor array outside of the tube. We measured gas flow rates from 1,000 to 30 sccm without significant changes in sensor performance using this intra-tube e-nose prototype. The tube could be bent to radii sensor performance similar to an unbent sensor.

  4. Parametric investigation of substrate temperatures on the properties of Zinc oxide deposited over a flexible polymeric substrate via spray technique

    Science.gov (United States)

    Rajagopalan, P.; Gagrani, Rohit; Nakamura, Daisuke; Okada, Tatsuo; Singh, Vipul; Palani, I. A.

    2016-09-01

    Here we report the influence of substrate temperature (300-500 °C) on the deposition and growth of ZnO over a Flexible polyimide film. Owing to its simplicity, large area deposition capability and Cost effectivity Spray Pyrolysis technique was used. We have modified the conventional process of Spray pyrolysis by spraying for shorter durations and repeating the process which in turn reduced the Island formation of ZnO. Moreover, this technique helped in maintaining the constant temperature and uniformity during the deposition as prolonged spraying reduces the temperature of the heating plate drastically. Photoluminescence (PL) reveals that at 350 and 400° C the defect have reduced. XRD reveals the crystallinity and Impurities present. FE-SEM reveals the structure morphology changes with the change in the substrate temperature. TGA was done to ensure that substrate does not undergoes dissociation at high temperature. It was observed at the film deposited at 400 °C was found to be more uniform, defect free and crystalline. Hence, IV characterization of the film deposited at 400 °C was done which showed good rectification behaviour of the Schottky diodes.

  5. Bacterial cellulose membrane as flexible substrate for organic light emitting devices

    Energy Technology Data Exchange (ETDEWEB)

    Legnani, C.; Vilani, C. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); Calil, V.L. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); LOEM-Molecular Optoelectronic Laboratory-Physics Department-PUC-Rio, Rio de Janeiro, RJ (Brazil); Barud, H.S. [Institute of Chemistry, Sao Paulo State University-UNESP, CP 355 Araraquara, SP (Brazil); Quirino, W.G. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); Achete, C.A. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); COPPE-Programa de Engenharia Metalurgica e de Materiais, UFRJ, Rio de Janeiro, RJ (Brazil); Ribeiro, S.J.L. [Institute of Chemistry, Sao Paulo State University-UNESP, CP 355 Araraquara, SP (Brazil); Cremona, M. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); LOEM-Molecular Optoelectronic Laboratory-Physics Department-PUC-Rio, Rio de Janeiro, RJ (Brazil)], E-mail: cremona@fis.puc-rio.br

    2008-12-01

    Bacterial cellulose (BC) membranes produced by gram-negative, acetic acid bacteria (Gluconacetobacter xylinus), were used as flexible substrates for the fabrication of Organic Light Emitting Diodes (OLED). In order to achieve the necessary conductive properties indium tin oxide (ITO) thin films were deposited onto the membrane at room temperature using radio frequency (r.f.) magnetron sputtering with an r.f. power of 30 W, at pressure of 8 mPa in Ar atmosphere without any subsequent thermal treatment. Visible light transmittance of about 40% was observed. Resistivity, mobility and carrier concentration of deposited ITO films were 4.90 x 10{sup -4} Ohm cm, 8.08 cm{sup 2}/V-s and - 1.5 x 10{sup 21} cm{sup -3}, respectively, comparable with commercial ITO substrates. In order to demonstrate the feasibility of devices based on BC membranes three OLEDs with different substrates were produced: a reference one with commercial ITO on glass, a second one with a SiO{sub 2} thin film interlayer between the BC membrane and the ITO layer and a third one just with ITO deposited directly on the BC membrane. The observed OLED luminance ratio was: 1; 0.5; 0.25 respectively, with 2400 cd/m{sup 2} as the value for the reference OLED. These preliminary results show clearly that the functionalized biopolymer, biodegradable, biocompatible bacterial cellulose membranes can be successfully used as substrate in flexible organic optoelectronic devices.

  6. Quantitative scanning thermal microscopy of graphene devices on flexible polyimide substrates

    Science.gov (United States)

    Sadeghi, Mir Mohammad; Park, Saungeun; Huang, Yu; Akinwande, Deji; Yao, Zhen; Murthy, Jayathi; Shi, Li

    2016-06-01

    A triple-scan scanning thermal microscopy (SThM) method and a zero-heat flux laser-heated SThM technique are investigated for quantitative thermal imaging of flexible graphene devices. A similar local tip-sample thermal resistance is observed on both the graphene and metal areas of the sample, and is attributed to the presence of a polymer residue layer on the sample surface and a liquid meniscus at the tip-sample junction. In addition, it is found that the tip-sample thermal resistance is insensitive to the temperature until it begins to increase as the temperature increases to 80 °C and exhibits an abrupt increase at 110 °C because of evaporation of the liquid meniscus at the tip-sample junction. Moreover, the variation in the tip-sample thermal resistance due to surface roughness is within the experimental tolerance except at areas with roughness height exceeding tens of nanometers. Because of the low thermal conductivity of the flexible polyimide substrate, the SThM measurements have found that the temperature rise in flexible graphene devices is more than one order of magnitude higher than those reported for graphene devices fabricated on a silicon substrate with comparable dimensions and power density. Unlike a graphene device on a silicon substrate where the majority of the electrical heating in the graphene device is conducted vertically through the thin silicon dioxide dielectric layer to the high-thermal conductivity silicon substrate, lateral heat spreading is important in the flexible graphene devices, as shown by the observed decrease in the average temperature rise normalized by the power density with decreasing graphene channel length from about 30 μm to 10 μm. However, it is shown by numerical heat transfer analysis that this trend is mainly caused by the size scaling of the thermal spreading resistance of the polymer substrate instead of lateral heat spreading by the graphene. In addition, thermoelectric effects are found to be negligible

  7. Fabrication and characterization of flexible Ag/ZnO Schottky diodes on polyimide substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, XinAn; Zhai, JunXia; Yu, XianKun; Ding, LingHong; Zhang, WeiFeng, E-mail: wfzhang@henu.edu.cn

    2013-12-02

    In this paper, we report on the fabrication of flexible Ag/ZnO Schottky diodes on polyimide substrates by pulsed laser deposition. The structural and optical properties of the ZnO films were investigated by X-ray diffractometry and spectrophotometry. The current–voltage (I–V) characteristics of flexible Schottky diodes with and without bending were measured at room temperature. The results show that the devices have good rectifying behaviors with an ideality factor of 2.8 and a Schottky barrier height of 0.54 eV according to the I–V characteristics. It was seen that the forward bias current–voltage characteristics at sufficiently large voltages have shown the effect of series resistance. The values of the ideality factor, series resistance and barrier height obtained from Cheung and Norde methods were compared, and it was seen that there was an agreement with each other. The results show that the electrical properties of flexible diodes change little when measured with or without bending condition, indicating that the devices have potential applications in flexible electronics. - Highlights: • Flexible Ag/ZnO Schottky diodes were fabricated. • The electrical parameters of the diodes were obtained and analyzed. • The electrical properties of the diodes with bending were also discussed.

  8. Fabrication of single-crystalline plasmonic nanostructures on transparent and flexible amorphous substrates

    Science.gov (United States)

    Mori, Tomohiro; Mori, Takeshi; Tanaka, Yasuhiro; Suzaki, Yoshifumi; Yamaguchi, Kenzo

    2017-01-01

    A new experimental technique is developed for producing a high-performance single-crystalline Ag nanostructure on transparent and flexible amorphous substrates for use in plasmonic sensors and circuit components. This technique is based on the epitaxial growth of Ag on a (001)-oriented single-crystalline NaCl substrate, which is subsequently dissolved in ultrapure water to allow the Ag film to be transferred onto a wide range of different substrates. Focused ion beam milling is then used to create an Ag nanoarray structure consisting of 200 cuboid nanoparticles with a side length of 160 nm and sharp, precise edges. This array exhibits a strong signal and a sharp peak in plasmonic properties and Raman intensity when compared with a polycrystalline Ag nanoarray. PMID:28216626

  9. Surface morphology changes of graphene on flexible PET substrate upon thermal annealing.

    Science.gov (United States)

    Samal, Monica; Lee, Jong Min; Park, Won Il; Yi, Dong Kee; Paik, Ungyu; Lee, Chang-Lyoul

    2011-11-01

    The performance of a polymer photovoltaic device using multilayered graphene on an amorphous PET substrate as the electrode was studied. The changes in surface morphology of graphene coated polyethylene terephthalate (PETG) substrate upon thermal annealing were investigated by atomic force microscopy (AFM), field emission scanning electron microscope (FE-SEM) and current-voltage characteristics. The root mean square (RMS) roughness of PETG substrate before annealing was 36.5 nm that decreased to 11.5 nm after 10 min thermal annealing at 110 degrees C. The mean grain size of the substrate decreased from 2301 nm2 to 848 nm2. The PETG surface became smooth when thermally annealed as the voids created by the bubbles in the graphene layer were filled up with thermal expansion of the PET substrate. However, cracks present initially on the graphene due to surface stress between the graphene and PET layer grew further upon annealing that deteriorated the device performance. This study on the graphene surface morphology change upon annealing and the consequent drop in device performance vis-à-vis an ITO glass electrode shows potential drawback of solar cell device fabrication on such flexible substrates.

  10. High-resolution and high-conductive electrode fabrication on a low thermal resistance flexible substrate

    Science.gov (United States)

    Kang, Bongchul; Kno, Jinsung; Yang, Minyang

    2011-07-01

    Processes based on the liquid-state pattern transfer, like inkjet printing, have critical limitations including low resolution and low electrical conductivity when fabricating electrodes on low thermal resistance flexible substrates such as polyethylene terephthalate (PET). Those are due to the nonlinear transfer mechanism and the limit of the sintering temperature. Although the laser direct curing (LDC) of metallic inks is an alternative process to improve the resolution, it is also associated with the disadvantages of causing thermal damage to the polymer substrate. This paper suggests the laser induced pattern adhesion transfer method to fabricate electrodes of both high electrical conductivity and high resolution on a PET substrate. First, solid patterns are cost-effectively created by the LDC of the organometallic silver ink on a glass that is optically and thermally stable. The solid patterns sintered on the glass are transferred to the PET substrate by the photo-thermally generated adhesion force of the substrate. Therefore, we achieved electrodes with a minimum line width of 10 µm and a specific resistance of 3.6 μΩcm on the PET substrate. The patterns also showed high mechanical reliability.

  11. Laser direct writing of 40 GHz RF components on flexible substrates

    Science.gov (United States)

    Zacharatos, F.; Iliadis, N.; Kanakis, J.; Bakopoulos, P.; Avramopoulos, H.; Zergioti, I.

    2016-05-01

    Flexible electronics have emerged as a very promising alternative of CMOS compatible electronics for a plethora of applications. Laser microfabrication techniques, such as selective laser patterning and sintering are compatible with flexible substrates and have demonstrated impressive results in the field of flexible electronic circuits and sensors. However, laser based manufacturing of radio frequency (RF) passive components or devices is still at an early stage. In this work we report on the all-laser fabrication of Silver Co-Planar Waveguides (CPWs) on polyethylene-naphthalate (PEN) substrates employing flat-top optics to achieve uniform laser fluence and thus high fabrication precision and reproducibility but also to mitigate the thermal effects of nanosecond laser pulses. The CPWs have been fabricated to match the impedance of 50 Ω ports of an Anritsu vector network analyzer operating from 40 MHz to 40 GHz. The all laser fabrication process consisted in the selective laser sintering of square dies on a Silver Nano Particle layer spin-coated on a PEN substrate followed by the selective laser patterning of the CPWs with a ns pulsed Nd:YAG laser source operating at 532 nm, according to the optimized parameters extracted from a previous studies of the authors. The CPWs have been characterized electrically at the 0.04-40 GHz regime and found to be excellent transmission lines with a 40 GHz 3 dB bandwidth, owing to the high electrical conductivity of Ag and the excellent dielectric properties of PEN. This novel process is a milestone towards the RF technology transfer to flexible electronics with low cost and specs comparable to the CMOS compatible equivalents.

  12. Buckling patterns of thin films on compliant substrates: the effect of plasticity

    Energy Technology Data Exchange (ETDEWEB)

    Yin Jie; Chen Xi, E-mail: xichen@columbia.edu [Columbia Nanomechanics Research Center, Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027 (United States)

    2011-02-02

    Most previous studies on spontaneous buckling pattern formations in thin films on compliant substrates were limited to elastic deformation, where the herringbone mode is the most often observed under equi-biaxial compression. In practice, plastic deformation is often encountered in ductile metal and polymer films. The effect of plasticity on buckling patterns is explored in this paper using extensive finite element simulations, where the film is assumed to be elastic-perfectly plastic. It is found that upon equi-biaxial compression, depending on the competition among the yield strain, critical buckling strain and applied strain, three new types of patterns may emerge: the plastic diamond-like pattern, the elastoplastic square lattice pattern and the elastoplastic sharp herringbone pattern, and their characteristics are compared with the elastic herringbone mode. Moreover, unique features including the asymmetry in crests and troughs, the sharp saw-like undulation profile and varying wavelengths with applied strain are observed for some types of the new patterns. The study may find its potential applications in the design of stretchable electronics, fabrication of micro/nanofluid channels or channel networks, and morphogenesis of tissues and plants, among others.

  13. Laser scribing of CIGS thin-film solar cell on flexible substrate

    Science.gov (United States)

    Hwang, David J.; Kuk, Seungkuk; Wang, Zhen; Fu, Shi; Zhang, Tao; Kim, Gayeon; Kim, Won Mok; Jeong, Jeung-hyun

    2017-01-01

    Laser scribing technology has been actively developed for thin-film solar cell fabrication taking a number of advantages over mechanical scribing. Its non-contact processing nature enables reliable and precise scribing processes. In particular, it is almost unavoidable to use laser scribing method for fabricating high-quality flexible thin-film solar cells. Despite the fundamental merits that laser scribing can offer, still a number of challenges should be addressed in order to replace the mechanical counterpart for wider range of thin-film solar cells. In this study, we explore optimal laser scribing conditions for copper-indium-gallium-selenide (CIGS) thin-film solar cells, especially based on flexible polyimide (PI) substrate in close comparison with that based on soda-lime glass substrate. Picosecond-pulsed laser of repetition rate up to 100 kHz and wavelength of 532 nm ( 12 ps temporal pulse width) was mainly tested, and scribing speed in the range of 0.01-1 m/s was examined with a few different laser focal spot diameters (27, 34, and 62 μm). Main focus of this study is in understanding distinct laser scribing mechanisms for flexible substrate configurations, thereby finding out intrinsic optimal processing parameters. One of the most critical requirements is to prevent possible damage or deformation of underlying thin-film layer(s) or PI substrate. Effect of microstructures of thin films (in particular, Mo and CIGS) on the scribing behavior was also examined. In order to further improve the performance of the scribing process and reduce the laser power budget as well, mild gas injection scheme was tested.

  14. Very high frequency plasma deposited amorphous/nanocrystalline silicon tandem solar cells on flexible substrates

    Science.gov (United States)

    Liu, Y.

    2010-02-01

    The work in this thesis is to develop high quality intrinsic layers (especially nc-Si:H) for micromorph silicon tandem solar cells/modules on plastic substrates following the substrate transfer method or knows as the Helianthos procedure. Two objectives are covered in this thesis: (1) preliminary work on trial and optimization of single junction and tandem cells on glass substrate, (2) silicon film depositions on Al foil, and afterwards the characterization and development of these cells/modules on a plastic substrate. The first objective includes the development of suitable ZnO:Al TCO for nc Si:H single junction solar cells, fabrication of the aimed micromorph tandem solar cells on glass, and finally the optimization of the nc-Si:H i-layer for the depositions afterwards on Al foil. Chapter 3 addresses the improvement of texture etching of ZnO:Al by studying the HCl etching effect on ZnO:Al films sputter-deposited in a set substrate heater temperature series. With the texture-etched ZnO:Al front TCO, a single junction nc-Si:H solar cell was deposited with an initial efficiency of 8.33%. Chapter 4 starts with studying the light soaking and annealing effects on micromorph tandem solar cell. In the end, a highly stabilized bottom cell current limited tandem cell was made. The tandem shows an initial efficiency of 10.2%, and degraded only 6.9% after 1600 h of light soaking. In Chapter 5, the nc-Si:H i-layers were studied in 3 pressure and inter-electrode distance series. The correlations between plasma physics and the consequent i-layers’ properties are investigated. We show that the Raman crystalline ratio and porosity of the nc-Si:H layer have an interesting relation with the p•d product. By varying p and d, device quality nc-Si:H layer can be deposited at a high rate of 0.6 nm/s. These results in fact are a very important step for the second objective. The second objective is covered by the entire Chapter 6. All silicon layers are deposited on special aluminum

  15. Microbes on a Bottle: Substrate, Season and Geography Influence Community Composition of Microbes Colonizing Marine Plastic Debris.

    Science.gov (United States)

    Oberbeckmann, Sonja; Osborn, A Mark; Duhaime, Melissa B

    2016-01-01

    Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate) (PET) drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5-6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae-all known to degrade complex carbon substrates) and diatoms (e.g. Coscinodiscophytina, Bacillariophytina). The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm) communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact with the PET

  16. Template-Free Mesoporous Electrochromic Films on Flexible Substrates from Tungsten Oxide Nanorods.

    Science.gov (United States)

    Heo, Sungyeon; Kim, Jongwook; Ong, Gary K; Milliron, Delia J

    2017-09-13

    Low-temperature processed mesoporous nanocrystal thin films are platforms for fabricating functional composite thin films on flexible substrates. Using a random arrangement of anisotropic nanocrystals can be a facile solution to generate pores without templates. However, the tendency for anisotropic particles to spontaneously assemble into a compact structure must be overcome. Here, we present a method to achieve random networking of nanorods during solution phase deposition by switching their ligand-stabilized colloidal nature into a charge-stabilized nature by a ligand-stripping chemistry. Ligand-stripped tungsten suboxide (WO2.72) nanorods result in uniform mesoporous thin films owing to repulsive electrostatic forces preventing nanorods from densely packing. Porosity and pore size distribution of thin films are controlled by changing the aspect ratio of the nanorods. This template-free mesoporous structure, achieved without annealing, provides a framework for introducing guest components, therefore enabling our fabrication of inorganic nanocomposite electrochromic films on flexible substrates. Following infilling of niobium polyoxometalate clusters into pores and successive chemical condensation, a WOx-NbOx composite film is produced that selectively controls visible and near-infrared light transmittance without any annealing required. The composite shows rapid switching kinetics and can be stably cycled between optical states over 2000 times. This simple strategy of using anisotropic nanocrystals gives insight into mesoporous thin film fabrication with broader applications for flexible devices.

  17. Fully integrated patterned carbon nanotube strain sensors on flexible sensing skin substrates for structural health monitoring

    Science.gov (United States)

    Burton, Andrew R.; Kurata, Masahiro; Nishino, Hiromichi; Lynch, Jerome P.

    2016-04-01

    New advances in nanotechnology and material processing is creating opportunities for the design and fabrication of a new generation of thin film sensors that can used to assess structural health. In particular, thin film sensors attached to large areas of the structure surface has the potential to provide spatially rich data on the performance and health of a structure. This study focuses on the development of a fully integrated strain sensor that is fabricated on a flexible substrate for potentially use in sensing skins. This is completed using a carbon nanotube-polymer composite material that is patterned on a flexible polyimide substrate using optical lithography. The piezoresistive carbon nanotube elements are integrated into a complete sensing system by patterning copper electrodes and integrating off-the-shelf electrical components on the flexible film for expanded functionality. This diverse material utilization is realized in a versatile process flow to illustrate a powerful toolbox for sensing severity, location, and failure mode of damage on structural components. The fully integrated patterned carbon nanotube strain sensor is tested on a quarter-scale, composite beam column connection. The results and implications for future structural damage detection are discussed.

  18. Simple one step spray process for CuInS2 / In2S3 heterojunctions on flexible substrates for photovoltaic applications

    Science.gov (United States)

    Thomas, Titu; Kumar, K. Rajeev; Kartha, C. Sudha; Vijayakumar, K. P.

    2015-09-01

    Flexible semiconducting devices such as solar cells and displays have been a recent attraction. Unlike heavy, brittle glass substrates, plastics and metallic foils have advantage of flexibility. They also have added advantages like good thermal stability and high melting point. In this paper we present a very simple method for the growth of Copper Indium Sulphide (CIS) films by depositing merely Indium Sulphide (InS) directly over the Cu foil using simple and economical chemical spray pyrolysis technique. The effects of volume of precursor solution on structural and morphological properties of the films were studied. Finally trials on heterojunctions with a structure of Cu foil/CIS/InS/Ag were also employed. Further improvement on heterojunction is expected by optimizing the morphological and structural properties of the film.

  19. Water and oil repellency of flexible silica-coated polymeric substrates

    Science.gov (United States)

    Hsieh, Chien-Te; Cheng, Yu-Shun; Hsu, Shu-Min; Lin, Jia-Yi

    2010-06-01

    A facile coating technique was used for the one-step creation of silica-sphere layers onto flexible polypropylene (PP) substrates, which showed the enhanced repellency toward liquid droplets with different surface tensions, ranging from 25.6 to 72.3 mN/m. One-step solution preparation comprised the homogenous mixing of colloidal silica nanospheres and perfluoroalkyl methacrylic copolymer, and the resulting F-silica slurry was subsequently deposited over the PP films, which showed good adhesion. The flexible silica-coated polymeric film displayed a remarkable repellency toward water and oil drops, when compared with the F-coated PP flat film. The silica-stacking layers on the PP substrate generated a roughened surface, owing to the creation of bionic surface hierarchically combined with multiple-scale architecture. To clarify this, the wetted fraction was determined from Cassie-Baxter equation, and the work of adhesion, based on Young-Duprè equation, was used to examine the sliding ability of the resulting polymeric films. The cross-cut test incorporated with film bending proved the excellent adherence between silica layer and PP substrate. A satisfactory durability in water and oil immersions for 10 days showed that the resulting PP film possesses strong adhesion and better repellency for a long period, confirming a promising commercial feasibility.

  20. A concept for direct deposition of thin film batteries on flexible polymer substrate

    Science.gov (United States)

    Glenneberg, Jens; Andre, Felix; Bardenhagen, Ingo; Langer, Frederieke; Schwenzel, Julian; Kun, Robert

    2016-08-01

    In this paper, the preparation and characteristics of all-solid-state thin film batteries (TFB) are described. In contrast to the state-of-the-art TFB preparation processes, only room temperature processes are used. The cathode is based on amorphous molybdenum(VI) oxide (MoO3), for the electrolyte lithium phosphorus oxynitride (LiPON) is employed and lithium metal acts as anode active material. The cycling stability and rate performance were examined and are discussed. The material set shows a very high cycling stability and excellent rate capability. Performing 550 full cycles at a current density of 202.5 μA cm-2 (10C) a discharge capacity fade of around 15% could be observed. Furthermore, at higher current densities of 2 μA cm-2 (145C) about one third of the initial discharge capacity remained. Using the proposed technology a shift from inorganic rigid substrates, such as glass to flexible polymer substrates is enabled. The performance of the MoO3/LiPON/Li TFBs on glass and flexible polyimide substrates were tested and are discussed within this paper.

  1. Field-effect modulation of the thermoelectric characteristics of silicon nanowires on plastic substrates

    Science.gov (United States)

    Choi, Jinyong; Jeon, Youngin; Cho, Kyoungah; Kim, Sangsig

    2016-12-01

    In this study, we demonstrate the substantial enhancement of the thermoelectric power factors of silicon nanowires (SiNWs) on plastic substrates achievable by field-effect modulation. The Seebeck coefficient and electrical conductivity are adjusted by varying the charge carrier concentration via electrical modulation with a gate voltage in the 0 to ±5 range, thus enhancing the power factors from 2.08 to 935 μW K-2 m-1) for n-type SiNWs, and from 453 to 944 μW K-2 m-1) for p-type SiNWs. The electrically modulated thermoelectric characteristics of SiNWs are analyzed and discussed.

  2. A low-temperature ZnO nanowire ethanol gas sensor prepared on plastic substrate

    Science.gov (United States)

    Lin, Chih-Hung; Chang, Shoou-Jinn; Hsueh, Ting-Jen

    2016-09-01

    In this work, a low-temperature ZnO nanowire ethanol gas sensor was prepared on plastic substrate. The operating temperature of the ZnO nanowire ethanol gas sensor was reduced to room temperature using ultraviolet illumination. The experimental results indicate a favorable sensor response at low temperature, with the best response at 60 °C. The results also reveal that the ZnO nanowire ethanol gas sensor can be easily integrated into portable products, whose waste heat can improve sensor response and achieve energy savings, while energy consumption can be further reduced by solar irradiation.

  3. Large area Germanium Tin nanometer optical film coatings on highly flexible aluminum substrates

    Science.gov (United States)

    Jin, Lichuan; Zhang, Dainan; Zhang, Huaiwu; Fang, Jue; Liao, Yulong; Zhou, Tingchuan; Liu, Cheng; Zhong, Zhiyong; Harris, Vincent G.

    2016-09-01

    Germanium Tin (GeSn) films have drawn great interest for their visible and near-infrared optoelectronics properties. Here, we demonstrate large area Germanium Tin nanometer thin films grown on highly flexible aluminum foil substrates using low-temperature molecular beam epitaxy (MBE). Ultra-thin (10–180 nm) GeSn film-coated aluminum foils display a wide color spectra with an absorption wavelength ranging from 400–1800 nm due to its strong optical interference effect. The light absorption ratio for nanometer GeSn/Al foil heterostructures can be enhanced up to 85%. Moreover, the structure exhibits excellent mechanical flexibility and can be cut or bent into many shapes, which facilitates a wide range of flexible photonics. Micro-Raman studies reveal a large tensile strain change with GeSn thickness, which arises from lattice deformations. In particular, nano-sized Sn-enriched GeSn dots appeared in the GeSn coatings that had a thickness greater than 50 nm, which induced an additional light absorption depression around 13.89 μm wavelength. These findings are promising for practical flexible photovoltaic and photodetector applications ranging from the visible to near-infrared wavelengths.

  4. Transparent resistive switching memory using aluminum oxide on a flexible substrate

    Science.gov (United States)

    Yeom, Seung-Won; Shin, Sang-Chul; Kim, Tan-Young; Ha, Hyeon Jun; Lee, Yun-Hi; Shim, Jae Won; Ju, Byeong-Kwon

    2016-02-01

    Resistive switching memory (ReRAM) has attracted much attention in recent times owing to its fast switching, simple structure, and non-volatility. Flexible and transparent electronic devices have also attracted considerable attention. We therefore fabricated an Al2O3-based ReRAM with transparent indium-zinc-oxide (IZO) electrodes on a flexible substrate. The device transmittance was found to be higher than 80% in the visible region (400-800 nm). Bended states (radius = 10 mm) of the device also did not affect the memory performance because of the flexibility of the two transparent IZO electrodes and the thin Al2O3 layer. The conduction mechanism of the resistive switching of our device was explained by ohmic conduction and a Poole-Frenkel emission model. The conduction mechanism was proved by oxygen vacancies in the Al2O3 layer, as analyzed by x-ray photoelectron spectroscopy analysis. These results encourage the application of ReRAM in flexible and transparent electronic devices.

  5. Sub-second carbon-nanotube-mediated microwave sintering for high-conductivity silver patterns on plastic substrates

    Science.gov (United States)

    Jung, Sunshin; Chun, Su Jin; Han, Joong Tark; Woo, Jong Seok; Shon, Cha-Hwa; Lee, Geon-Woong

    2016-02-01

    A method of microwave sintering that is mediated by carbon nanotubes (CNTs) has been developed to obtain high-conductivity Ag patterns on the top of heat-sensitive plastic substrates within a short time. The Ag patterns are printed on CNTs formed on plastic substrates and rapidly heated to a great extent by the heat transferred from the microwave-heated CNTs. The conductivity of the microwave-sintered Ag patterns reaches ~39% that of bulk Ag within 1 s without substrate deformation. Furthermore, microwave sintering enhances the adhesion of Ag patterns to the thermoplastic substrates because the sintering causes interfacial fusion between the Ag patterns and the substrates, and CNTs physically connect the patterns with the substrates.A method of microwave sintering that is mediated by carbon nanotubes (CNTs) has been developed to obtain high-conductivity Ag patterns on the top of heat-sensitive plastic substrates within a short time. The Ag patterns are printed on CNTs formed on plastic substrates and rapidly heated to a great extent by the heat transferred from the microwave-heated CNTs. The conductivity of the microwave-sintered Ag patterns reaches ~39% that of bulk Ag within 1 s without substrate deformation. Furthermore, microwave sintering enhances the adhesion of Ag patterns to the thermoplastic substrates because the sintering causes interfacial fusion between the Ag patterns and the substrates, and CNTs physically connect the patterns with the substrates. Electronic supplementary information (ESI) available: Temperature difference in Ag/CNT/PC samples; the carbon content and electrical performance after microwave sintering; microwave sintering of Ag/CNT patterns; physical connection between the substrate and sintered Ag lines; touch-piano (figure and movie). See DOI: 10.1039/c5nr08082g

  6. Silver Nanowire Top Electrodes in Flexible Perovskite Solar Cells using Titanium Metal as Substrate.

    Science.gov (United States)

    Lee, Minoh; Ko, Yohan; Min, Byoung Koun; Jun, Yongseok

    2016-01-08

    Flexible perovskite solar cells (FPSCs) have various applications such as wearable electronic textiles and portable devices. In this work, we demonstrate FPSCs on a titanium metal substrate employing solution-processed silver nanowires (Ag NWs) as the top electrode. The Ag NW electrodes were deposited on top of the spiro-MeOTAD hole transport layer by a carefully controlled spray-coating method at moderate temperatures. The power conversion efficiency (PCE) reached 7.45 % under AM 1.5 100 mW cm(-2) illumination. Moreover, the efficiency for titanium-based FPSCs decreased only slightly (by 2.6 % of the initial value) after the devices were bent 100 times. With this and other advances, fully solution-based indium-free flexible photovoltaics, advantageous in terms of price and processing, have the potential to be scaled into commercial production. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Photodetectors based on single-walled carbon nanotubes and thiamonomethinecyanine J-aggregates on flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Fedorov, I. V., E-mail: i-v-fedorov@mail.ru; Emel’yanov, A. V.; Romashkin, A. V.; Bobrinetskiy, I. I. [National Research University of Electronic Technology (MIET) (Russian Federation)

    2015-09-15

    The present paper is devoted to observations of the photoresistive effect in multilayer structures with a sensitive layer of J-aggregates of thiamonomethinecyanine polymethine dye and a transparent electrode of a conductive carbon-nanotube network on a flexible polyethylenenaphtalate substrate. The effect of narrow-band emission with a wavelength of 465 nm on a change in the conductivity of the fabricated structures is studied. The prepared samples are studied by atomic-force microscopy, Raman spectroscopy, and spectrophotometry methods. It is shown that these structures are photosensitive to the indicated spectral region, and the dye layer is a film of dye J-aggregates. The change in the sample conductivity upon exposure to light one hundred times exceeds the dark conductivity. In general, the principal possibility of developing a photoresistive detector based on J-aggregates of cyanine dyes on flexible supports on account of the use of transparent and conductive carbon-nanotube layers is shown.

  8. Monopole quasi-Yagi antenna on polyimide substrate for flexible electronics

    Science.gov (United States)

    Liu, Jianying; Dai, Fang; Zhang, Yichen; Yu, Xin; Cai, Lulu; Zuo, Panpan; Wang, Mengjun

    2017-01-01

    In this paper, a flexible monopole quasi-Yagi antenna printed on 50um thick polyimide substrate is designed for integration within modern flexible electronic devices. The antenna has a wide working band (5.22-6.6 GHz) that covers WLAN 5.8GHz (5.725-5.825GHz). Parameters changes of proposed modeling are analyzed to achieve desired impedance matching and resonant frequency. The reflection coefficient, gain and radiation efficiency are indicated to be still robust when the proposed antenna is under various bending directions. It is worth noting that radiation patterns have an effect when antenna is bent in the y-axis direction. The antenna prototype is fabricated and tested where the simulated results agree with measured ones.

  9. A new subregion mesh method for the investigation of the elastic-plastic impact in flexible multibody systems

    Science.gov (United States)

    Chen, Peng; Liu, Jin-Yang; Lu, Guang-Can

    2017-02-01

    Impact processes between flexible bodies often lead to local stress concentration and wave propagation of high frequency. Therefore, the modeling of flexible multibody systems involving impact should consider the local plastic deformation and the strict requirements of the spatial discretization. Owing to the nonlinearity of the stiffness matrix, the reduction of the element number is extremely important. For the contact-impact problem, since different regions have different requirements regarding the element size, a new subregion mesh method is proposed to reduce the number of the unnecessary elements. A dynamic model for flexible multibody systems with elastic-plastic contact impact is established based on a floating frame of reference formulation and complete Lagrange incremental nonlinear finite-element method to investigate the effect of the elastic-plastic deformation as well as spatial discretization. Experiments on the impact between two bodies are carried out to validate the correctness of the elastic-plastic model. The proposed formulation is applied to a slider-crank system with elastic-plastic impact.

  10. In situ X-ray scattering of perovskite solar cell active layers roll-to-roll coated on flexible substrates

    DEFF Research Database (Denmark)

    Rossander, Lea Hildebrandt; Larsen-Olsen, Thue T.; Dam, Henrik Friis

    2016-01-01

    and crystallographic development. Using our in situ slot-die micro roll-to-roll coater setup, we measured small and wide angle X-ray scattering in grazing incidence while the material dried, enabling us to follow the crystallization from just after the deposition and up to 25 minutes later. The data showed differing......In an effort to understand recent results showing differences between the power conversion efficiencies of lead halide (CH3NH3PbI3-xClx) solar cells on glass versus flexible substrates, this study investigates the influence that substrate and processing methods have on morphological...... that the flexible substrates absorb part of the solvent, thereby delaying evaporation and changing the solvent environment around the perovskite. As a further test, we produced solar cells with the same substrates and confirmed that the ones made on flexible substrates performed worse than those made on glass...

  11. Bendable high-frequency microwave switches formed with single-crystal silicon nanomembranes on plastic substrates

    Science.gov (United States)

    Yuan, Hao-Chih; Qin, Guoxuan; Celler, George K.; Ma, Zhenqiang

    2009-07-01

    This letter presents realization of bendable rf switches operating at microwave frequencies formed with single-crystal Si nanomembranes (SiNMs) on a plastic substrate. Selectively doped 200-nm-thick SiNM is lifted off from silicon-on-insulator and transferred to a polymer substrate to form lateral P-intrinsic-N (PIN) diodes with minimized parasitic resistances. A single-pole single-throw switch, consisting of two PIN diodes connected in a shunt-series configuration, demonstrated very low insertion loss and high isolation from dc up to 20 GHz. The level of performance indicates a promise of properly processed single-crystal semiconductor nanomembranes for high-frequency applications in a number of consumer and military systems.

  12. Fabrication of dye solar cell on flexible substrate using ITO-PEN film

    Science.gov (United States)

    Sahmer, Ahmad Zahrin; Mohamed, Norani Muti

    2012-09-01

    Dye solar cell based on nanocrystalline TiO2 has the potential to reach low cost in future indoor power applications. To realize its application for powering the electrical appliances, dye solar cell (DSC) must be made mechanically robust and flexible where indium-doped tin oxide (ITO-PEN) film substrate will be used as the working electrode. In terms of fabrication process, the ITO-PEN film is easier to handle in a process such as cutting of larger film sheet into smaller individual modules or cell. Moreover the processing of the film into complete flexible solar cells can be realized by means of a continuous roll to roll production process. The paper reports the study on the fabrication of dye solar cell on the flexible ITO-PEN. Here, the temperature constraint in the sintering process is addressed by using low temperature of 150°C and further enhanced with direct heat on the photo-electrode at 140°C to achieve a good bonding between the ITO and the deposited TiO2 film. The TiO2 coated ITO-PEN substrate was then soaked in commercial N719 dye, assembled into test cell, and tested under the standard test condition at irradiance of 1000 W/m2 with AM1.5 solar simulator. The fabricated flexible ITO-PEN DSC test cell was found to have an efficiency of 2.1% which is comparatively lower to DSC cell based on TCO rigid glass. This is attributed to the overall higher internal resistance of TiO2 film as a result of incomplete decomposition of ethyl cellulose at low sintering temperature.

  13. Effective surface modification by chemical solution deposition for flexible metal substrates

    Science.gov (United States)

    Du, Wei; Bai, Yue-Ling; Wang, Jing; Fang, Jianhui; Fan, Feng; Liu, Zhiyong; Guo, Yanqun; Bai, Chuanyi; Cai, Chuanbing

    2017-03-01

    Solution deposition planarization (SDP) was used to modify the flexible metal substrates for high temperature superconductor (HTS) tapes to ensure an available and effective surface for subsequent growth of buffer films. The surface morphologies with different tape speeds and coating layers were systematically investigated. 16 layers SDP-films decreased the surface roughness (RMS) from 11.74 to 0.788 nm for Hastelloy C-276 and 12 layers SDP-films decreased the RMS from 20.93 to 0.903 nm for SUS 304. Follow-up study confirmed that the low value of RMS (coated conductor, which further reduced the cost of raw materials.

  14. Design and development of RFID and RFID-enabled sensors on flexible low cost substrates

    CERN Document Server

    Yang, Li

    2009-01-01

    This book presents a step-by-step discussion of the design and development of radio frequency identification (RFID) and RFID-enabled sensors on flexible low cost substrates for UHF frequency bands. Various examples of fully function building blocks (design and fabrication of antennas, integration with ICs and microcontrollers, power sources, as well as inkjet-printing techniques) demonstrate the revolutionary effect of this approach in low cost RFID and RFID-enabled sensors fields. This approach could be easily extended to other microwave and wireless applications as well. The first chapter de

  15. Mirroring the dynamic magnetic behavior of magnetostrictive Co/(Ag,Cu,Ta) multilayers grown onto rigid and flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Agra, K.; Gomes, R.R. [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Della Pace, R.D. [Departamento de Física, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Dorneles, L.S. [Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Bohn, F. [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Corrêa, M.A., E-mail: marciocorrea@dfte.ufrn.br [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil)

    2015-11-01

    We investigate the magnetoimpedance effect in a wide frequency range in magnetostrictive Co/(Ag,Cu,Ta) multilayers grown onto rigid and flexible substrates. We observe a direct correlation between structural and quasi-static magnetic properties and the magnetoimpedance effect, since they are directly dependent on the nature of the spacer material. Moreover, we verify that all these properties are insensitive to the kind of employed substrate. We compare the magnetoimpedance results measured for multilayers in rigid and flexible substrates and discuss them in terms of different mechanisms that govern the impedances changes, magnetic anisotropy, structural character, and of numerical calculation results found in the literature. The fact that magnetostrictive multilayers can be reproduced in distinct kinds of substrates corresponds to an important advance for their applicability. The results place multilayers grown onto flexible substrates as attractive candidates for application as probe element in the development of MI-based sensor devices. - Highlights: • Correlation between structural and magnetic properties. • Dynamic magnetic behavior of multilayers trough MI effect. • Mirroring the dynamic magnetic behavior in flexible and rigid substrates. • Flexible substrate applications for magnetostrictive alloys.

  16. Patterned deposition of metal-organic frameworks onto plastic, paper, and textile substrates by inkjet printing of a precursor solution.

    Science.gov (United States)

    Zhuang, Jin-Liang; Ar, Deniz; Yu, Xiu-Jun; Liu, Jin-Xuan; Terfort, Andreas

    2013-09-06

    Flexible in many aspects: inkjet printing of metal-organic frameworks permits their larger area, high-resolution deposition in any desired pattern, even in the form of gradients or shades. When flexible substrates are used, many applications can be envisioned, such as sensing and capture of hazardous gases for personal safety measures.

  17. Directed assembly of carbon nanotubes on soft substrates for use as a flexible biosensor array

    Science.gov (United States)

    Koh, Juntae; Yi, Mihye; Lee, Byung Yang; Kim, Tae Hyun; Lee, Joohyung; Jhon, Young Min; Hong, Seunghun

    2008-12-01

    We have developed a method to selectively assemble and align carbon nanotubes (CNTs) on soft substrates for use as flexible biosensors. In this strategy, a thin oxide layer was deposited on soft substrates via low temperature plasma enhanced chemical vapor deposition, and a linker-free assembly process was applied on the oxide surface where the assembly of carbon nanotubes was guided by methyl-terminated molecular patterns on the oxide surface. The electrical characterization of the fabricated CNT devices exhibited a typical p-type gating effect and 1/f noise behavior. The bare oxide regions near CNTs were functionalized with glutamate oxidase to fabricate selective biosensors to detect two forms of glutamate substances existing in different situations: L-glutamic acid, a neurotransmitting material, and monosodium glutamate, a food additive.

  18. Directed-Assembly of Carbon Nanotubes on Soft Substrates for Flexible Biosensor Array

    Science.gov (United States)

    Lee, Hyoung Woo; Koh, Juntae; Lee, Byung Yang; Kim, Tae Hyun; Lee, Joohyung; Hong, Seunghun; Yi, Mihye; Jhon, Young Min

    2009-03-01

    We developed a method to selectively assemble and align carbon nanotubes (CNTs) on soft substrates for flexible biosensors. In this strategy, thin oxide layer was deposited on soft substrates via low temperature plasma enhanced chemical vapor deposition, and linker-free assembly process was applied onto the oxide surface where the assembly of carbon nanotubes was guided by methyl-terminated molecular patterns on the oxide surface. The electrical characterization of the fabricated CNT devices exhibited typical p-type gating effect and 1/f noise behavior. The bare oxide regions near CNTs were functionalized with glutamate oxidase to fabricate selective biosensors to detect two forms of glutamate substances existing in different situations: L-glutamic acid, a neuro-transmitting material, and monosodium glutamate, a food additive.

  19. Unambiguous magnetoelastic effect on residual anisotropy in thin films deposited on flexible substrates

    Science.gov (United States)

    Gueye, Mouhamadou; Lupo, Pierpaolo; Zighem, Fatih; Faurie, Damien; Belmeguenai, Mohamed; Olusola Adeyeye, Adekunle

    2016-04-01

    The residual magnetic uniaxial anisotropy of thin films deposited on flexible substrates was studied to elucidate its main origins. For that purpose, we sputtered 20 nm thick films of Co40Fe40B20 and Ni80Fe20 on Kapton® substrates. After measuring magnetomechanical properties of each system, we have shown that the weak residual anisotropy in the Ni80Fe20 film, compared to that of Co40Fe40B20, is perfectly correlated to its low magnetostriction coefficient. As a consequence, we conclude that this residual anisotropy is undoubtedly due to the unavoidable bending of the system, even if it is invisible with the naked eye (radius of several centimeters).

  20. Ultrafast direct fabrication of flexible substrate-supported designer plasmonic nanoarrays

    Science.gov (United States)

    Hu, Yaowu; Kumar, Prashant; Xu, Rong; Zhao, Kejie; Cheng, Gary J.

    2015-12-01

    Fabrication of plasmonic nanostructures has been an important topic for their potential applications in photonic and optoelectronic devices. Among plasmonic materials, gold is one of the most promising materials due to its low ohmic loss at optical frequencies and high oxidation resistance. However, there are two major bottlenecks for its industrial applications: (1) the need for large-scale fabrication technology for high-precision plasmonic nanostructures; and (2) the need to integrate the plasmonic nanostructures on various substrates. While conventional top-down approaches involve high cost and give low throughput, bottom-up approaches suffer from irreproducibility and low precision. Herein, we report laser shock induced direct imprinting of large-area plasmonic nanostructures from physical vapor deposited (PVD) gold thin film on a flexible commercial free-standing aluminum foil. Among the important characteristics of the laser-shock direct imprinting is their unique capabilities to reproducibly deliver designer plasmonic nanostructures with extreme precision and in an ultrafast manner. Excellent size tunability (from several μm down to 15 nm) has been achieved by varying mold dimensions and laser parameters. The physical mechanism of the hybrid film imprinting is elaborated by finite element modeling. A mechanical robustness test of the hybrid film validates a significantly improved interfacial contact between gold arrays and the underlying substrate. The strong optical field enhancement was realized in the large-area fabricated engineered gold nanostructures. Low concentration molecular sensing was investigated employing the fabricated structures as surface-enhanced Raman scattering (SERS) substrates. The ability to ultrafast direct imprint plasmonic nanoarrays on a flexible substrate at multiscale is a critical step towards roll-to-roll manufacturing of multi-functional devices which is poised to inspire several emerging applications.Fabrication of

  1. MnO2-Based Electrochemical Supercapacitors on Flexible Carbon Substrates

    Science.gov (United States)

    Tadjer, Marko J.; Mastro, Michael A.; Rojo, José M.; Mojena, Alberto Boscá; Calle, Fernando; Kub, Francis J.; Eddy, Charles R.

    2014-04-01

    Manganese dioxide films were grown on large area flexible carbon aerogel substrates. Characterization by x-ray diffraction confirmed α-MnO2 growth. Three types of films were compared as a function of hexamethylenetetramine (HMTA) concentration during growth. The highest concentration of HM TA produced MnO2 flower-like films, as observed by scanning electron microscopy, whose thickness and surface coverage lead to both a higher specific capacitance and higher series resistance. Specific capacitance was measured to be 64 F/g using a galvanostatic setup, compared to the 47 F/g-specific capacitance of the carbon aerogel substrate. Such supercapacitor devices can be fabricated on large area sheets of carbon aerogel to achieve high total capacitance.

  2. Semiconductor-Free Nonvolatile Resistive Switching Memory Devices Based on Metal Nanogaps Fabricated on Flexible Substrates via Adhesion Lithography

    KAUST Repository

    Semple, James

    2017-01-02

    Electronic memory cells are of critical importance in modern-day computing devices, including emerging technology sectors such as large-area printed electronics. One technology that has being receiving significant interest in recent years is resistive switching primarily due to its low dimensionality and nonvolatility. Here, we describe the development of resistive switching memory device arrays based on empty aluminum nanogap electrodes. By employing adhesion lithography, a low-temperature and large-area compatible nanogap fabrication technique, dense arrays of memory devices are demonstrated on both rigid and flexible plastic substrates. As-prepared devices exhibit nonvolatile memory operation with stable endurance, resistance ratios >10⁴ and retention times of several months. An intermittent analysis of the electrode microstructure reveals that controlled resistive switching is due to migration of metal from the electrodes into the nanogap under the application of an external electric field. This alternative form of resistive random access memory is promising for use in emerging sectors such as large-area electronics as well as in electronics for harsh environments, e.g., space, high/low temperature, magnetic influences, radiation, vibration, and pressure.

  3. Light Trapping in Thin Film Silicon Solar Cells on Plastic Substrates

    Science.gov (United States)

    de Jong, M. M.

    2013-01-01

    In the search for sustainable energy sources, solar energy can fulfil a large part of the growing demand. The biggest threshold for large-scale solar energy harvesting is the solar panel price. For drastic cost reductions, roll-to-roll fabrication of thin film silicon solar cells using plastic substrates can be a solution. In this thesis, we investigate the possibilities of depositing thin film solar cells directly onto cheap plastic substrates. Micro-textured glass and sheets, which have a wide range of applications, such as in green house, lighting etc, are applied in these solar cells for light trapping. Thin silicon films can be produced by decomposing silane gas, using a plasma process. In these types of processes, the temperature of the growing surface has a large influence on the quality of the grown films. Because plastic substrates limit the maximum tolerable substrate temperature, new methods have to be developed to produce device-grade silicon layers. At low temperature, polysilanes can form in the plasma, eventually forming dust particles, which can deteriorate device performance. By studying the spatially resolved optical emission from the plasma between the electrodes, we can identify whether we have a dusty plasma. Furthermore, we found an explanation for the temperature dependence of dust formation; Monitoring the formation of polysilanes as a function of temperature using a mass-spectrometer, we observed that the polymerization rate is indeed influenced by the substrate temperature. For solar cell substrate material, our choice was polycarbonate (PC), because of its low cost, its excellent transparency and its relatively high glass transition temperature of 130-140°C. At 130°C we searched for deposition recipes for device quality silicon, using a very high frequency plasma enhanced chemical deposition process. By diluting the feedstock silane with hydrogen gas, the silicon quality can be improved for amorphous silicon (a-Si), until we reach the

  4. Substrate pre-treatment of flexible material for printed electronics with carbon nanotube based ink

    Science.gov (United States)

    Denneulin, Aurore; Bras, Julien; Blayo, Anne; Neuman, Charles

    2011-02-01

    In this work, an innovative solution was developed in order to make paper-based material, used traditionally in the packaging and labelling industries, compatible with the printing of functional conductive inks. In order to avoid the deterioration of the ink functionalities due to different paper properties, a UV-curing inkjettable primer layer was developed. This pre-treatment enables homogeneous surface properties such as smoothness, absorption capacity and surface energy to be obtained, for almost all the examined substrates. To confirm the positive impact of such pre-treatment, conductivity has been measured when using a new conductive ink, combining the processability of the PEDOT-PSS conductive polymer with the high electrical properties of carbon nanotubes (CNTs). Significant improvement has been measured for all paper materials and similar conductivity (close to reference PET film) has been obtained whatever the substrate involved. This pre-treatment now makes it possible to consider paper-based material as a potential substrate for printed electronics. In this case, the substrate adaptation technique offers an innovative solution to produce low-cost and flexible electronics.

  5. Back-to-back tunable ferroelectric resonator filters on flexible organic substrates.

    Science.gov (United States)

    Courrèges, Stanis; Lacroix, Benjamin; Amadjikpe, Arnaud; Phillips, Stan; Zhao, Zhiyong; Choi, Kwang; Hunt, Andrew; Papapolymerou, John

    2010-06-01

    This paper presents the design and the fabrication of two low-loss X-band back-to-back tunable ferroelectric resonator filters on flexible liquid crystal polymer substrates using wire-bonded BST capacitors as analog tuning elements. The back-to-back topology consists of three resonators on both sides of the substrate coupled by apertures in their common ground plane, allowing the overall size of the filter to be reduced. BST varactors made on a sapphire substrate are easily diced and mounted on the polymer substrates to achieve the desired tuning. Both 3-pole tunable filters show a 1-dB bandwidth of 8 to 10%, low insertion loss (3.6 to 1.95 dB for the best one) with bias voltages from 0 to 35 V, a better compactness compared with classical tunable structures (reduced footprint area by 30% for the best filter) and a frequency tuning of about 11 to 13% at 8 GHz. The demonstrated feasibility opens interesting prospects for the fabrication of compact tunable filters with more resonators.

  6. Substrate pre-treatment of flexible material for printed electronics with carbon nanotube based ink

    Energy Technology Data Exchange (ETDEWEB)

    Denneulin, Aurore, E-mail: Aurore@polypore.fr [Polypore - 27, bd Louise Michel, F-92230 Gennevilliers (France); Laboratory of Pulp and Paper Science and Graphic Arts (LGP2) (UMR 5518 CNRS-CTP-INPG), Grenoble Institute of Technology, INP Grenoble - PAGORA, 461 Rue de la Papeterie, BP 65, 38402 St Martin d' Heres Cedex (France); Bras, Julien, E-mail: Julien.Bras@grenoble-inp.fr [Laboratory of Pulp and Paper Science and Graphic Arts (LGP2) (UMR 5518 CNRS-CTP-INPG), Grenoble Institute of Technology, INP Grenoble - PAGORA, 461 Rue de la Papeterie, BP 65, 38402 St Martin d' Heres Cedex (France); Blayo, Anne, E-mail: Anne.Blayo@grenoble-inp.fr [Laboratory of Pulp and Paper Science and Graphic Arts (LGP2), UMR 5518 CNRS-CTP-INPG, Grenoble Institute of Technology (INP Grenoble - PAGORA), 461 Rue de la Papeterie, BP 65, 38402 St Martin d' Heres Cedex (France); Neuman, Charles [Polypore - 27, bd Louise Michel, F-92230 Gennevilliers (France)

    2011-02-01

    In this work, an innovative solution was developed in order to make paper-based material, used traditionally in the packaging and labelling industries, compatible with the printing of functional conductive inks. In order to avoid the deterioration of the ink functionalities due to different paper properties, a UV-curing inkjettable primer layer was developed. This pre-treatment enables homogeneous surface properties such as smoothness, absorption capacity and surface energy to be obtained, for almost all the examined substrates. To confirm the positive impact of such pre-treatment, conductivity has been measured when using a new conductive ink, combining the processability of the PEDOT-PSS conductive polymer with the high electrical properties of carbon nanotubes (CNTs). Significant improvement has been measured for all paper materials and similar conductivity (close to reference PET film) has been obtained whatever the substrate involved. This pre-treatment now makes it possible to consider paper-based material as a potential substrate for printed electronics. In this case, the substrate adaptation technique offers an innovative solution to produce low-cost and flexible electronics.

  7. Substrates adoption methodology (SAM) to achieve “Fast, Flexible, Future (F3)” pharmaceutical production processes

    DEFF Research Database (Denmark)

    Singh, Ravendra; Rozada-Sanchez, Raquel; Wrate, Tim;

    within the template. In this way the substrates adoption methodology helps to achieve “fast, flexible, future (F3)” pharmaceutical production processes by adapting a recently designed generic modular process-plant. The supporting tools for the substrate adoption are: (1) an ontological knowledge...

  8. Capacitive tunnels in single-walled carbon nanotube networks on flexible substrate

    Science.gov (United States)

    Iqbal, M. Z.; Iqbal, M. W.; Eom, Jonghwa; Ahmad, Muneer; Ferrer-Anglada, Núria

    2012-03-01

    We report the analysis of single-walled carbon nanotube networks, which are expected to be suitable as miniaturized flexible radio frequency RC filters and also have important implications for high frequency devices. The surface morphology obtained by atomic force microscopy shows that most of the growth on polypropylene carbonate substrate is homogeneous. The large value of peak intensity ratio of G and D band in Raman spectra indicates the high purity network. Nyquist plots of carbon nanotube networks on a flexible substrate are close to real circles, indicating that the material is conducting, and suggest a simple equivalent circuit having a resistor in parallel with a capacitor. The Bode plots give the dependence of real and imaginary impedances on frequency. While at high frequency, the impedance decreases, due to generation of capacitance between a single-walled carbon nanotube; at low frequency, it shows the normal behavior, having constant value. The tunnels among different carbon nanotubes are capable of storing electric charge. The accumulative capacitances of tunnels for three varied concentrations are calculated by electrochemical impedance spectroscopy simulations to fit the observed Nyquist plots.

  9. Efficient organometal trihalide perovskite planar-heterojunction solar cells on flexible polymer substrates.

    Science.gov (United States)

    Docampo, Pablo; Ball, James M; Darwich, Mariam; Eperon, Giles E; Snaith, Henry J

    2013-01-01

    Organometal trihalide perovskite solar cells offer the promise of a low-cost easily manufacturable solar technology, compatible with large-scale low-temperature solution processing. Within 1 year of development, solar-to-electric power-conversion efficiencies have risen to over 15%, and further imminent improvements are expected. Here we show that this technology can be successfully made compatible with electron acceptor and donor materials generally used in organic photovoltaics. We demonstrate that a single thin film of the low-temperature solution-processed organometal trihalide perovskite absorber CH3NH3PbI3-xClx, sandwiched between organic contacts can exhibit devices with power-conversion efficiency of up to 10% on glass substrates and over 6% on flexible polymer substrates. This work represents an important step forward, as it removes most barriers to adoption of the perovskite technology by the organic photovoltaic community, and can thus utilize the extensive existing knowledge of hybrid interfaces for further device improvements and flexible processing platforms.

  10. Characteristics of strain-sensitive photonic crystal cavities in a flexible substrate.

    Science.gov (United States)

    No, You-Shin; Choi, Jae-Hyuck; Kim, Kyoung-Ho; Park, Hong-Gyu

    2016-11-14

    High-index semiconductor photonic crystal (PhC) cavities in a flexible substrate support strong and tunable optical resonances that can be used for highly sensitive and spatially localized detection of mechanical deformations in physical systems. Here, we report theoretical studies and fundamental understandings of resonant behavior of an optical mode excited in strain-sensitive rod-type PhC cavities consisting of high-index dielectric nanorods embedded in a low-index flexible polymer substrate. Using the three-dimensional finite-difference time-domain simulation method, we calculated two-dimensional transverse-electric-like photonic band diagrams and the three-dimensional dispersion surfaces near the first Γ-point band edge of unidirectionally strained PhCs. A broken rotational symmetry in the PhCs modifies the photonic band structures and results in the asymmetric distributions and different levels of changes in normalized frequencies near the first Γ-point band edge in the reciprocal space, which consequently reveals strain-dependent directional optical losses and selected emission patterns. The calculated electric fields, resonant wavelengths, and quality factors of the band-edge modes in the strained PhCs show an excellent agreement with the results of qualitative analysis of modified dispersion surfaces. Furthermore, polarization-resolved time-averaged Poynting vectors exhibit characteristic dipole-like emission patterns with preferentially selected linear polarizations, originating from the asymmetric band structures in the strained PhCs.

  11. Structure Analysis and Optical Parameters of Nano-scale ZnSe/Flexible Substrate Thin Film

    Science.gov (United States)

    Shaaban, E. R.; Yahia, I. S.; Sharaf, E. R.

    2016-09-01

    The ZnSe thin films with different thicknesses have been deposited on polymer substrates for flexible optical devices applications. The XRD of different thicknesses for ZnSe films reveals the cubic structure of the films oriented along the (1 1 1) direction. The structural parameters such as particle size (40.41-105.24 nm) and lattice strain (6.5 × 10-3-14.7 × 10-3 lin-2m-4) were evaluated. Also AFM was used in order to obtain quantitative information on microstructure properties. The optical constants, the refractive index n and the absorption index k have been calculated from transmittance T and reflectance R through the spectral range of 400-2500 nm using Swanepoel's method. The optical constants (n, k) were calculated in medium and transparent regions. The energy gap of direct transition for polycrystalline ZnSe thin films was calculated in the strong absorption region and found to be increased from 2.55 eV to 2.70 eV with the increasing the film thickness. ZnSe/flexible substrates are good candidates for optoelectronic devices.

  12. Advances in all-sputtered CdTe solar cells on flexible substrates

    Science.gov (United States)

    Wieland, Kristopher; Mahabaduge, Hasitha; Vasko, Anthony; Compaan, Alvin

    2010-03-01

    The University of Toledo II-VI semiconductor group has developed magnetron sputtering (MS) for the deposition of thin films of CdS, CdTe, and related materials for photovoltaic applications. On glass superstrates, we have reached air mass 1.5 efficiencies of 14%.[1] Recently we have studied the use of MS for the fabrication of thin-film CdS/CdTe cells on flexible polyimide superstrates. This takes advantage of the high film quality that can be achieved at substrate temperatures below 300 C when RF MS is used. Our recent CdS/CdTe solar cells have reached 10.5% on flexible polyimide substrates. [2] This all-sputtered cell (except for back contact) has a structure of polyimide/ZnO:Al/ZnO/CdS/CdTe/Cu/Au. The physics of this device will be discussed through the use of spectral quantum efficiency and current-voltage measurements as a function of CdTe layer thickness. Pathways toward further increases in device efficiencies will also be discussed. [1] Appl. Phys. Lett. 85, 684 (2004) [2] Phys. Stat. Sol. (B) 241, No. 3, 779--782 (2004)

  13. Flexibility.

    Science.gov (United States)

    Humphrey, L. Dennis

    1981-01-01

    Flexibility is an important aspect of all sports and recreational activities. Flexibility can be developed and maintained by stretching exercises. Exercises designed to develop flexibility in ankle joints, knees, hips, and the lower back are presented. (JN)

  14. Wagging the Tail: Essential Role of Substrate Flexibility in FAAH Catalysis.

    Science.gov (United States)

    Palermo, Giulia; Campomanes, Pablo; Neri, Marilisa; Piomelli, Daniele; Cavalli, Andrea; Rothlisberger, Ursula; De Vivo, Marco

    2013-02-12

    The serine hydrolase, fatty acid amide hydrolase (FAAH), is responsible for the intracellular degradation of anandamide and other bioactive fatty acid ethanolamides involved in the regulation of pain, inflammation, and other pathophysiological processes. The catalytic site of FAAH is composed of multiple cavities with mixed hydrophobic and hydrophilic properties, the role of which remains incompletely understood. Anandamide is thought to enter the active site through a "membrane-access" (MA) channel and position its flexible fatty acyl chain in a highly hydrophobic "acyl chain-binding" (AB) cavity to allow for hydrolysis to occur. Using microsecond molecular dynamics (MD) simulations of FAAH embedded in a realistic membrane/water environment, we show now that anandamide may not lock itself into the AB cavity but may rather assume catalytically significant conformations required for hydrolysis by moving its flexible arachidonoyl tail between the MA and AB cavities. This process is regulated by a phenylalanine residue (Phe432) located at the boundary between the two cavities, which may act as a "dynamic paddle." The results identify structural flexibility as a key determinant by which FAAH recognizes its primary lipid substrate.

  15. Laser-Direct Writing of Silver Metal Electrodes on Transparent Flexible Substrates with High-Bonding Strength.

    Science.gov (United States)

    Zhou, Weiping; Bai, Shi; Ma, Ying; Ma, Delong; Hou, Tingxiu; Shi, Xiaomin; Hu, Anming

    2016-09-21

    We demonstrate a novel approach to rapidly fabricate conductive silver electrodes on transparent flexible substrates with high-bonding strength by laser-direct writing. A new type of silver ink composed of silver nitrate, sodium citrate, and polyvinylpyrrolidone (PVP) was prepared in this work. The role of PVP was elucidated for improving the quality of silver electrodes. Silver nanoparticles and sintered microstructures were simultaneously synthesized and patterned on a substrate using a focused 405 nm continuous wave laser. The writing was completed through the transparent flexible substrate with a programmed 2D scanning sample stage. Silver electrodes fabricated by this approach exhibit a remarkable bonding strength, which can withstand an adhesive tape test at least 50 times. After a 1500 time bending test, the resistance only increased 5.2%. With laser-induced in-situ synthesis, sintering, and simultaneous patterning of silver nanoparticles, this technology is promising for the facile fabrication of conducting electronic devices on flexible substrates.

  16. Encapsulate-and-peel: fabricating carbon nanotube CMOS integrated circuits in a flexible ultra-thin plastic film

    Science.gov (United States)

    Gao, Pingqi; Zhang, Qing

    2014-02-01

    Fabrication of single-walled carbon nanotube thin film (SWNT-TF) based integrated circuits (ICs) on soft substrates has been challenging due to several processing-related obstacles, such as printed/transferred SWNT-TF pattern and electrode alignment, electrical pad/channel material/dielectric layer flatness, adherence of the circuits onto the soft substrates etc. Here, we report a new approach that circumvents these challenges by encapsulating pre-formed SWNT-TF-ICs on hard substrates into polyimide (PI) and peeling them off to form flexible ICs on a large scale. The flexible SWNT-TF-ICs show promising performance comparable to those circuits formed on hard substrates. The flexible p- and n-type SWNT-TF transistors have an average mobility of around 60 cm2 V-1 s-1, a subthreshold slope as low as 150 mV dec-1, operating gate voltages less than 2 V, on/off ratios larger than 104 and a switching speed of several kilohertz. The post-transfer technique described here is not only a simple and cost-effective pathway to realize scalable flexible ICs, but also a feasible method to fabricate flexible displays, sensors and solar cells etc.

  17. 25 GHz embedded-gate graphene transistors with high-k dielectrics on extremely flexible plastic sheets.

    Science.gov (United States)

    Lee, Jongho; Ha, Tae-Jun; Li, Huifeng; Parrish, Kristen N; Holt, Milo; Dodabalapur, Ananth; Ruoff, Rodney S; Akinwande, Deji

    2013-09-24

    Despite the widespread interest in graphene electronics over the past decade, high-performance graphene field-effect transistors (GFETs) on flexible substrates have been rarely achieved, even though this atomic sheet is widely understood to have greater prospects for flexible electronic systems. In this article, we report detailed studies on the electrical and mechanical properties of vapor synthesized high-quality monolayer graphene integrated onto flexible polyimide substrates. Flexible graphene transistors with high-k dielectric afforded intrinsic gain, maximum carrier mobilities of 3900 cm(2)/V·s, and importantly, 25 GHz cutoff frequency, which is more than a factor of 2.5 times higher than prior results. Mechanical studies reveal robust transistor performance under repeated bending, down to 0.7 mm bending radius, whose tensile strain is a factor of 2-5 times higher than in prior studies. In addition, integration of functional coatings such as highly hydrophobic fluoropolymers combined with the self-passivation properties of the polyimide substrate provides water-resistant protection without compromising flexibility, which is an important advancement for the realization of future robust flexible systems based on graphene.

  18. Design and synthesis of flexible switching 1 × 2 antenna array on Kapton substrate

    Science.gov (United States)

    Georges Rabobason, Yvon; Rigas, Grigorios; Swaisaenyakorn, Srijittar; Mirkhaydarov, Bobur; Ravelo, Blaise; Shkunov, Maxim; Young, Paul; Benjelloun, Nabil

    2016-06-01

    Flexible front- and back-end RF/analogue system antennas were recently emerged. However, little flexible antenna system design is available so far, in planar hybrid technology with surface mounted components. This paper describes the design feasibility of flexible switching 1 × 2 antenna array system. It acts as a switching antenna implemented in hexapole configuration. The system is comprised of a key element RF switch terminated by two identical patch antennas associated to half-wave elementary transmission lines (TLs). A detailed theory illustrating the global S-parameter model determination in function of the given RF-switch return and insertion losses is established. In difference to the conventional microwave circuit theory, the proposed equivalent S-parameter model is originally built with the non-standard optimized antenna load. Thus, the synthesis method of the terminal antenna input impedance and the output access line characteristic impedance is formulated in function of the specified return and optimal transmission losses. The design method and theoretical approach feasibility is verified with the demonstrator of flexible switching 1 × 2 antenna array printed on Kapton substrate. The circuit prototype is implemented in hybrid planar technology integrating patch antenna operating at about 6 GHz and a packaged GaAs RF switch associated to the RF/DC signal decoupling accessory mounted surface components. Simulations of the designed circuit transmission and isolation losses from 5.5 GHz to 7 GHz were carried out by using the commercial RF switch S-parameter touchstone model provided by the manufacturer. The simulated and measured return losses are compared and discussed. Then, the measured radiation patterns confirm the proposed switched antenna concept feasibility.

  19. Highly flexible, transparent, and low resistance indium zinc oxide-Ag-indium zinc oxide multilayer anode on polyethylene terephthalate substrate for flexible organic light light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sung-Woo; Jeong, Jin-A; Bae, Jung-Hyeok; Moon, Jong-Min; Choi, Kwang-Hyuk; Jeong, Soon Wook; Park, No-Jin [School of Advanced Materials and Systems Engineering, Kumoh National Institute of Technology (KIT), Gumi 730-701 (Korea, Republic of); Kim, Jang-Joo; Lee, Se Hyung [School of Materials Science and Engineering, Seoul National University and Organic Light Emitting Diodes Center, Sillim-dong, Seoul 151-741 (Korea, Republic of); Kang, Jae-Wook [Surface Technology Research Center, Korea Institute of Machinery and Materials, 66 Sangnam-dong, Changwon-si, Gyeongnam, 641-831 (Korea, Republic of); Yi, Min-Su [Department of Materials Science and Engineering, Kyungpook National University, Sangju, Gyeongbuk, 742-711 (Korea, Republic of); Kim, Han-Ki [School of Advanced Materials and Systems Engineering, Kumoh National Institute of Technology (KIT), Gumi 730-701 (Korea, Republic of)], E-mail: hkkim@kumoh.ac.kr

    2008-09-01

    The characteristics of indium zinc oxide (IZO)-Ag-IZO multilayer grown on a polyethylene terephthalate (PET) substrate were investigated for flexible organic light-emitting diodes (OLEDs). The IZO-Ag-IZO (IAI) multilayer anode exhibited a remarkably reduced sheet resistance of 6.93 {omega}/{open_square} and a high transmittance of 84.8%, despite the very thin thickness of the IZO (30 nm) layer. In addition, it was shown that electrical and optical properties of IAI anodes are critically dependent on the thickness of the Ag layer, due to the transition of Ag atoms from distinct islands to continuous films at a critical thickness (12 nm). Moreover, the IAI/PET sample showed more stable mechanical properties than an amorphous ITO/PET sample during the bending test due to the existence of a ductile Ag layer. The current density-voltage-luminance characteristics of flexible OLEDs fabricated on an IAI/PET substrate was better than those of flexible OLEDs fabricated on an ITO/PET substrate. This indicates that IAI multilayer anodes are promising flexible and transparent electrodes for flexible OLEDs.

  20. Screen-Printed Flexible Bandstop Filter on Polyethylene Terephthalate Substrate Based on Ag Nanoparticles

    Directory of Open Access Journals (Sweden)

    Rajendra Dhakal

    2015-01-01

    Full Text Available We present a low-power, cost-effective, highly reproducible, and disposable bandstop filter by employing high-throughput screen-printing technology. We apply large-scale printing strategies using silver-nanoparticle-based ink for the metallization of conductive wires to fabricate a bandstop filter on a polyethylene terephthalate (PET substrate. The filter exhibits an attenuation pole at 4.35 GHz with excellent in-and-out band characteristics. These characteristics reflect a rejection depth that is better than −25 dB with a return loss of −0.75 dB at the normal orientation of the PET substrate. In addition, the filter characteristics are observed at various bending angles (0°, 10°, and 20° of the PET substrate with an excellent relative standard deviation of less than 0.5%. These results confirm the accuracy, reproducibility, and independence of the resonance frequency. This screen-printing technology for well-defined nanostructures is more favorable than other complex photolithographic processes because it overcomes signal losses due to uneven surface distributions and thereby reveals a homogeneous distribution. Moreover, the proposed methodology enables incremental steps in the process of producing highly flexible and cost-effective printed-electronic radio devices.

  1. Hydrothermal growth of ZnO nanowires on flexible fabric substrates

    Science.gov (United States)

    Hong, Gwang-Wook; Yun, Sang-Ho; Kim, Joo-Hyung

    2016-04-01

    ZnO nanowires (NWs) would provide significant enhancement in sensitivity due to high surface to volume ratio. We investigated the first methodical study on the quantitative relationship between the process parameters of solution concentration ratio, structure, and physical and properties of ZnO NWs grown on different flexible fabric surfaces. To develop a fundamental following concerning various substrates, we controlled the growth speed of ZnO NWs and nanowires on cotton surface with easy and moderate cost fabrication method. Using ammonium hydroxide as the reactant with zinc nitrate hexahydrate, ZnO NWs layer have been grown on metal layers, instead of seed layer. ZnO NWs fabrication was done on different fabric substrates such as wool, nylon and polypropylene (PP). After the ZnO NWs grown to each substrates, we coated insulating layer with polyurethane (PU) and ethyl cellulose for prevent external intervention. Detailed electrical characterization was subsequently performed to reveal the working characteristics of the hybrid fabric. For electrical verification of fabricated ZnO NWs, we implemented measurement impact test and material properties with FFT analyzer and LCR meter.

  2. Ultrasmooth, Polydopamine Modified Surfaces for Block Copolymer Nanopatterning on Inert and Flexible Substrates

    Science.gov (United States)

    Katsumata, Reika; Cho, Joon Hee; Zhou, Sunshine; Kim, Chae Bin; Dulaney, Austin; Janes, Dustin; Ellison, Christopher

    Nature has engineered universal, catechol-containing adhesives that can be synthetically mimicked in the form of polydopamine (PDA). We exploited PDA to enable block copolymer (BCP) nanopatterning on a variety of soft material surfaces in a way that can potentially be applied to flexible electrical devices. Applying BCP nanopatterning to soft substrates is challenging because soft substrates are often chemically inert and possess incompatible low surface energies. In this study, we exploited PDA to enable the formation of BCP nanopatterns on a variety of surfaces such as Teflon, poly(ethylene terephthalate) (PET), and Kapton. While previous studies produced a PDA coating layer too rough for BCP nanopatterning, we succeeded in fabricating conformal and ultra-smooth surfaces of PDA by engineering the PDA coating process and post-sonication procedure. This chemically functionalized, biomimetic thin film (3 nm thick) served as a reactive platform for subsequently grafting a surface treatment to perpendicularly orient a lamellae-forming BCP layer. Furthermore, we demonstrated that a perfectly nanopatterned PDA-PET substrate can be bent without distorting or damaging the nanopattern in conditions that far exceeds typical bending curvatures in roll-to-roll manufacturing.

  3. The Use of Feature Parameters to Asses Barrier Properties of ALD coatings for Flexible PV Substrates

    Science.gov (United States)

    Blunt, Liam; Robbins, David; Fleming, Leigh; Elrawemi, Mohamed

    2014-03-01

    This paper reports on the recent work carried out as part of the EU funded NanoMend project. The project seeks to develop integrated process inspection, cleaning, repair and control systems for nano-scale thin films on large area substrates. In the present study flexible photovoltaic films have been the substrate of interest. Flexible PV films are the subject of significant development at present and the latest films have efficiencies at or beyond the level of Si based rigid PV modules. These flexible devices are fabricated on polymer film by the repeated deposition, and patterning, of thin layer materials using roll-to-roll processes, where the whole film is approximately 3um thick prior to encapsulation. Whilst flexible films offer significant advantages in terms of mass and the possibility of building integration (BIPV) they are at present susceptible to long term environmental degradation as a result of water vapor transmission through the barrier layers to the CIGS (Copper Indium Gallium Selenide CuInxGa(1-x)Se2) PV cells thus causing electrical shorts and efficiency drops. Environmental protection of the GIGS cell is provided by a thin (40nm) barrier coating of Al2O3. The highly conformal aluminium oxide barrier layer is produced by atomic layer deposition (ALD) where, the ultra-thin Al2O3 layer is deposited onto polymer thin films before these films encapsulate the PV cell. The surface of the starting polymer film must be of very high quality in order to avoid creating defects in the device layers. Since these defects reduce manufacturing yield, in order to prevent them, a further thin polymer coating (planarization layer) is generally applied to the polymer film prior to deposition. The presence of surface irregularities on the uncoated film can create defects within the nanometre-scale, aluminium oxide, barrier layer and these are measured and characterised. This paper begins by reporting the results of early stage measurements conducted to characterise

  4. Efficient coating of transparent and conductive carbon nanotube thin films on plastic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Ng, M H Andrew; Hartadi, Lysia T; Tan Huiwen; Poa, C H Patrick [Institute of Materials Research and Engineering, 3 Research Link, 117602 (Singapore)], E-mail: patrick-poa@imre.a-star.edu.sg

    2008-05-21

    Optically transparent and electrically conductive single-walled carbon nanotube (SWNT) thin films were fabricated at room temperature using a dip-coating technique. The film transparency and sheet resistance can be easily tailored by controlling the number of coatings. Aminopropyltriethoxysilane (APTS) was used as an adhesion promoter and, together with surfactant Triton X-100, greatly improved the SWNTs coating. Only five coats were required to obtain a sheet resistance of 2.05 {omega}{open_square} and film transparency of 84 %T. The dip-coated film after post-deposition treatment with nitric acid has a sheet resistance as low as 130 {omega}{open_square} at 69 %T. This technique is suitable for large-scale SWNT coating at room temperature and can be used on different types of substrates such as glass and plastics. This paper will discuss the role of the adhesion promoter and surfactant in the coating process.

  5. Crack formation mechanisms during micro and macro indentation of diamond-like carbon coatings on elastic-plastic substrates

    DEFF Research Database (Denmark)

    Thomsen, N.B.; Fischer-Cripps, A.C.; Swain, M.V.

    1998-01-01

    In the present study crack formation is investigated on both micro and macro scale using spherical indenter tips. in particular, systems consisting of elastic coatings that are well adhered to elastic-plastic substrates are studied. Depth sensing indentation is used on the micro scale and Rockwell...... indentation on the macro scale. The predominant driving force for coating failure and crack formation during indentation is plastic deformation of the underlying substrate. The aim is to relate the mechanisms creating both delamination and cohesive cracking on both scales with fracture mechanical models...

  6. Use of microcutting for high throughput electrode patterning on a flexible substrate

    Science.gov (United States)

    Janka, M.; Tuukkanen, S.; Tuorila, H.; Viheriälä, J.; Honkanen, M.; Stingelin, N.; Lupo, D.

    2014-01-01

    The use of printing technologies is promising for low-cost manufacturing of flexible, light-weight and large-area electronics, such as electronic paper or solar cells. Here, we demonstrate a microcutting technique and methods to fabricate cutting blades for the patterning of metal structure on a polymer substrate. Microcutting is done using a hot embossing and nanoimprinting techniques. The metallic fine patterns obtained by using stamps fabricated using different techniques are compared. Combination of microcutting and our recently proposed dielectric alignment opens up a novel platform for a variety of applications, such as the fabrication of metal crossover or organic field effect transistors as well as contact resistance measurement of metal-semiconductor junctions.

  7. Growth and Transfer of Monolithic Horizontal ZnO Nanowire Superstructures onto Flexible Substrates

    KAUST Repository

    Xu, Sheng

    2010-04-28

    A method of fabricating horizontally aligned ZnO nanowire (NW) arrays with full control over the width and length is demonstrated. A cross-sectional view of the NWs by transmission electron microscopy shows a "mushroom-like" structure. Novel monolithic multisegment superstructures are fabricated by making use of the lateral overgrowth. Ultralong horizontal ZnO NWs of an aspect ratio on the order often thousand are also demonstrated. These horizontal NWs are lifted off and transferred onto a flexible polymer substrate, which may have many great applications in horizontal ZnO NW-based nanosensor arrays, light-emitting diodes, optical gratings, integrated circuit interconnects, and high-output-power alternating-current nanogenerators. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA.

  8. Split-Ring Resonator-Based Strain Sensor on Flexible Substrates for Glaucoma Detection

    Science.gov (United States)

    Ekinci, Gizem; Deniz Yalcinkaya, Arda; Dundar, Gunhan; Torun, Hamdi

    2016-10-01

    This paper presents split-ring resonator-based strain sensors designed and characterized for glaucoma detection application. The geometry of the sensor is optimized such that it can be embedded in a contact lens. Silver conductive paint is to form the sensors realized on flexible substrates made of cellulose acetate and latex rubber. The devices are excited and interrogated using a pair of monopole antennas and the characteristics of devices with different curvature profiles are obtained. The sensitivity of the device, i.e. the change in resonant frequency for a unit change in radius of curvature, on acetate film is calculated as -4.73 MHz/mm and the sensitivity of the device on latex is 33.2 MHz/mm. The results indicate that the demonstrated device is suitable for glaucoma diagnosis.

  9. Thin and flexible solid-state organic ionic plastic crystal-polymer nanofibre composite electrolytes for device applications.

    Science.gov (United States)

    Howlett, Patrick C; Ponzio, Florian; Fang, Jian; Lin, Tong; Jin, Liyu; Iranipour, Nahid; Efthimiadis, Jim

    2013-09-07

    All solid-state organic ionic plastic crystal-polymer nanofibre composite electrolytes are described for the first time. The new composite materials exhibit enhanced conductivity, excellent thermal, mechanical and electrochemical stability and allow the production of optically transparent, free-standing, flexible, thin film electrolytes (10's μms thick) for application in electrochemical devices. Stable cycling of a lithium cell incorporating the new composite electrolyte is demonstrated, including cycling at lower temperatures than previously possible with the pure material.

  10. Fully integrated carbon nanotube composite thin film strain sensors on flexible substrates for structural health monitoring

    Science.gov (United States)

    Burton, A. R.; Lynch, J. P.; Kurata, M.; Law, K. H.

    2017-09-01

    Multifunctional thin film materials have opened many opportunities for novel sensing strategies for structural health monitoring. While past work has established methods of optimizing multifunctional materials to exhibit sensing properties, comparatively less work has focused on their integration into fully functional sensing systems capable of being deployed in the field. This study focuses on the advancement of a scalable fabrication process for the integration of multifunctional thin films into a fully integrated sensing system. This is achieved through the development of an optimized fabrication process that can create a broad range of sensing systems using multifunctional materials. A layer-by-layer deposited multifunctional composite consisting of single walled carbon nanotubes (SWNT) in a polyvinyl alcohol and polysodium-4-styrene sulfonate matrix are incorporated with a lithography process to produce a fully integrated sensing system deposited on a flexible substrate. To illustrate the process, a strain sensing platform consisting of a patterned SWNT-composite thin film as a strain-sensitive element within an amplified Wheatstone bridge sensing circuit is presented. Strain sensing is selected because it presents many of the design and processing challenges that are core to patterning multifunctional thin film materials into sensing systems. Strain sensors fabricated on a flexible polyimide substrate are experimentally tested under cyclic loading using standard four-point bending coupons and a partial-scale steel frame assembly under lateral loading. The study reveals the material process is highly repeatable to produce fully integrated strain sensors with linearity and sensitivity exceeding 0.99 and 5 {{V}}/{ε }, respectively. The thin film strain sensors are robust and are capable of high strain measurements beyond 3000 μ {ε }.

  11. Resistive switching of Pt/TiO x /Pt devices fabricated on flexible Parylene-C substrates

    Science.gov (United States)

    Khiat, Ali; Cortese, Simone; Serb, Alexander; Prodromakis, Themistoklis

    2017-01-01

    Pt/TiO x /Pt resistive switching (RS) devices are considered to be amongst the most promising candidates in memristor family and the technology transfer to flexible substrates could open the way to new opportunities for flexible memory implementations. Hence, an important goal is to achieve a fully flexible RS memory technology. Nonetheless, several fabrication challenges are present and must be solved prior to achieving reliable device fabrication and good electronic performances. Here, we propose a fabrication method for the successful transfer of Pt/TiO x /Pt stack onto flexible Parylene-C substrates. The devices were electrically characterised, exhibiting both digital and analogue memory characteristics, which are obtained by proper adjustment of pulsing schemes during tests. This approach could open new application possibilities of these devices in neuromorphic computing, data processing, implantable sensors and bio-compatible neural interfaces.

  12. Dewetting of thin films on flexible substrates via direct-write laser exposure

    Science.gov (United States)

    Ferrer, Anthony Jesus

    Microelectromechanical systems (MEMS) have enabled a wide variety of technologies both in the consumer space and in industrial/research areas. At the market level, such devices advance by the invention and innovation of production techniques. Additionally, there has been increased demand for flexible versions of such MEMS devices. Thin film patterning, represents a key technology for the realization of such flexible electronics. Patterns and methods that can be directly written into the thin film allow for design modification on the fly with the need for harsh chemicals and long etching steps. Laser-induced dewetting has the potential to create patterns in thin films at both the microscopic and nanoscopic level without wasting deposited material. This thesis presents the first demonstration of high-speed direct-write patterning of metallic thin films that uses a laser-induced dewetting phenomenon to prevent material loss. The ability to build film material with this technique is explored using various scanning geometries. Finally, demonstrations of direct-write dewetting of a variety of thin films will be presented with special consideration for high melting point metals deposited upon polymer substrates.

  13. Transparent bipolar resistive switching memory on a flexible substrate with indium-zinc-oxide electrodes

    Science.gov (United States)

    Yeom, Seung-Won; Ha, Hyeon Jun; Park, Junsu; Shim, Jae Won; Ju, Byeong-Kwon

    2016-12-01

    We fabricated transparent indium zinc oxide (IZO)/TiO2/IZO devices on flexible polyethylene phthalate (PET) substrates. These devices demonstrate bipolar resistive switching behavior, exhibit a transmittance greater than 80 % for visible light, and have stable resistive switching properties, including long retention and good endurance. In addition, the devices were investigated based on their temperature dependence; the results show metallic properties in the low-resistance state (LRS) and semiconducting properties in the high-resistance state (HRS). The conduction mechanism for resistive switching in our device was well-fitted with Ohmic conduction in the LRS and Poole-Frenkel emission in the HRS. The mechanism could be explained by the formation and the rupture of the conduction paths formed by the movement of oxygen ions and vacancies. Moreover, acute bending of the devices did not affect the memory characteristics because of the pliability of both the IZO electrodes and the thin oxide layer. These results indicate potential applications as resistive random access memories in future flexible, transparent electronic devices.

  14. Low-cost flexible supercapacitors based on laser reduced graphene oxide supported on polyethylene terephthalate substrate

    Science.gov (United States)

    Ghoniem, Engy; Mori, Shinsuke; Abdel-Moniem, Ahmed

    2016-08-01

    A controlled high powered CO2 laser system is used to reduce and pattern graphene oxide (GO) film supported onto a flexible polyethylene terephthalate (PET) substrate. The laser reduced graphene oxide (rGO) film is characterized and evaluated electrochemically in the absence and presence of an overlying anodicaly deposited thin film of pseuodcapactive MnO2 as electrodes for supercapacitor applications using aqueous electrolyte. The laser treatment of the GO film leads to an overlapped structure of defective multi-layer rGO sheets with an electrical conductivity of 273 S m-1. The rGO and MnO2/rGO electrodes exhibit specific capacitance in the range of 82-107 and 172-368 Fg-1 at applied current range of 0.1-1.0 mA cm-2 and retain 98 and 95% of their initial capacitances after 2000 cycles at a current density of 1.0 mA cm-2, respectively. Also, the rGO is assigned as an electrode material for flexible conventionally stacked and interdigitated in-plane supercapacitor structures using gel electrolyte. Three electrode architectures of 2, 4, and 6 sub-electrodes are studied for the interdigital in-plane design. The device with interdigital 6 sub-electrodes architecture I-PS(6) delivers power density of 537.1 Wcm-3 and an energy density of 0.45 mWh cm-3.

  15. Structural, optical, and electrical-transport properties of Al-P-O inorganic layer coated on flexible stainless steel substrate

    Science.gov (United States)

    Kim, Moojin; Min, Jinhyuk; Kwak, Yongsu; Kim, Doori; Kim, Kyoung-Bo; Song, Jonghyun

    2017-03-01

    We coated inorganic layer containing oxygen, aluminium, phosphorus, and negligible sodium (APO) on stainless steel (STS) by using slot-die coating method and studied its application prospects as a substrate for flexible devices. The APO layer was compositionally uniform in overall area with an amorphous crystal structure. Surface morphology characterization of STS exhibited an improved flatness after the APO layer coating process. The optical property characterization of the APO film carried out by measuring optical reflectance spectrum and refractive index. We also investigated the electrical-transport mechanism in the APO layer. These experimental observations imply the possibility of potential application of APO-STS as a substrate for flexible devices.

  16. Theoretical investigations of the interfacial sliding and buckling of graphene on a flexible substrate

    Science.gov (United States)

    Cui, Zhen; Guo, Jian-Gang

    2016-12-01

    Two interfacial failure modes, shear sliding and buckling, of graphene on a flexible substrate subjected to uniaxial compression are investigated. The shear sliding starts at the edge region, and buckling starts at the middle region of graphene. Using shear-lag cohesive zone models and finite element (FE) simulations, the critical strain and maximum strain of graphene are predicted for the interfacial sliding failure. Then, the critical strain for the onset of buckling is derived via the theory of continuum mechanics with the van der Waals (vdW) interaction between graphene and the substrate surface taken into consideration. By comparison of the two critical failure strains and maximum strain of graphene, it is found that there exists a critical length of graphene. As the graphene length is larger than it, interfacial failure goes through four stages of development with increasing loading, including sliding and buckling. Conversely, the buckling of graphene will not occur. Finally, the influence of the interfacial adhesion energy and geometric size of graphene on the critical strains for interfacial sliding and buckling are discussed.

  17. Three-dimensional nanopillar-array photovoltaics on low-cost and flexible substrates.

    Science.gov (United States)

    Fan, Zhiyong; Razavi, Haleh; Do, Jae-won; Moriwaki, Aimee; Ergen, Onur; Chueh, Yu-Lun; Leu, Paul W; Ho, Johnny C; Takahashi, Toshitake; Reichertz, Lothar A; Neale, Steven; Yu, Kyoungsik; Wu, Ming; Ager, Joel W; Javey, Ali

    2009-08-01

    Solar energy represents one of the most abundant and yet least harvested sources of renewable energy. In recent years, tremendous progress has been made in developing photovoltaics that can be potentially mass deployed. Of particular interest to cost-effective solar cells is to use novel device structures and materials processing for enabling acceptable efficiencies. In this regard, here, we report the direct growth of highly regular, single-crystalline nanopillar arrays of optically active semiconductors on aluminium substrates that are then configured as solar-cell modules. As an example, we demonstrate a photovoltaic structure that incorporates three-dimensional, single-crystalline n-CdS nanopillars, embedded in polycrystalline thin films of p-CdTe, to enable high absorption of light and efficient collection of the carriers. Through experiments and modelling, we demonstrate the potency of this approach for enabling highly versatile solar modules on both rigid and flexible substrates with enhanced carrier collection efficiency arising from the geometric configuration of the nanopillars.

  18. Designing interlayers to improve the mechanical reliability of transparent conductive oxide coatings on flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun-Hye; Yang, Chan-Woo; Park, Jin-Woo [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2012-05-01

    In this study, we investigate the effect of interlayers on the mechanical properties of transparent conductive oxide (TCO) on flexible polymer substrates. Indium tin oxide (ITO), which is the most widely used TCO film, and Ti, which is the most widely used adhesive interlayer, are selected as the coating and the interlayer, respectively. These films are deposited on the polymer substrates using dc-magnetron sputtering to achieve varying thicknesses. The changes in the following critical factors for film cracking and delamination are analyzed: the internal stress ({sigma}{sup i}) induced in the coatings during deposition using a white light interferometer, the crystallinity using a transmission electron microscope, and the surface roughness of ITO caused by the interlayer using an atomic force microscope. The resistances to the cracking and delamination of ITO are evaluated using a fragmentation test. Our tests and analyses reveal the important role of the interlayers, which significantly reduce the compressive {sigma}{sup i} that is induced in the ITO and increase the resistance to the buckling delamination of the ITO. However, the relaxation of {sigma}{sup i} is not beneficial to cracking because there is less compensation for the external tension as {sigma}{sup i} further decreases. Based on these results, the microstructural control is revealed as a more influential factor than {sigma}{sup i} for improving crack resistance.

  19. Designing interlayers to improve the mechanical reliability of transparent conductive oxide coatings on flexible substrates

    Science.gov (United States)

    Kim, Eun-Hye; Yang, Chan-Woo; Park, Jin-Woo

    2012-05-01

    In this study, we investigate the effect of interlayers on the mechanical properties of transparent conductive oxide (TCO) on flexible polymer substrates. Indium tin oxide (ITO), which is the most widely used TCO film, and Ti, which is the most widely used adhesive interlayer, are selected as the coating and the interlayer, respectively. These films are deposited on the polymer substrates using dc-magnetron sputtering to achieve varying thicknesses. The changes in the following critical factors for film cracking and delamination are analyzed: the internal stress (σi) induced in the coatings during deposition using a white light interferometer, the crystallinity using a transmission electron microscope, and the surface roughness of ITO caused by the interlayer using an atomic force microscope. The resistances to the cracking and delamination of ITO are evaluated using a fragmentation test. Our tests and analyses reveal the important role of the interlayers, which significantly reduce the compressive σi that is induced in the ITO and increase the resistance to the buckling delamination of the ITO. However, the relaxation of σi is not beneficial to cracking because there is less compensation for the external tension as σi further decreases. Based on these results, the microstructural control is revealed as a more influential factor than σi for improving crack resistance.

  20. Interactions between chronic ethanol consumption and thiamine deficiency on neural plasticity, spatial memory and cognitive flexibility

    Science.gov (United States)

    Vedder, Lindsey C.; Hall, Joseph M.; Jabrouin, Kimberly R.; Savage, Lisa M.

    2015-01-01

    Background Many alcoholics display moderate to severe cognitive dysfunction accompanied by brain pathology. A factor confounded with prolonged heavy alcohol consumption is poor nutrition and many alcoholics are thiamine deficient. Thus, thiamine deficiency (TD) has emerged as a key factor underlying alcohol–related brain damage (ARBD). TD in humans can lead to Wernicke Encephalitis that can progress into Wernicke–Korsakoff Syndrome and these disorders have a high prevalence among alcoholics. Animal models are critical for determining the exact contributions of ethanol- and TD-induced neurotoxicity, as well as the interactions of those factors to brain and cognitive dysfunction. Methods Adult rats were randomly assigned to one of six treatment conditions: Chronic ethanol treatment (CET) where rats consumed a 20% v/v solution of ethanol over 6 months; Severe pyrithiamine-induced TD (PTD-MAS); Moderate PTD (PTD-EAS); Moderate PTD followed by CET (PTD-CET); Moderate PTD during CET (CET-PTD); Pair-fed control (PF). After recovery from treatment, all rats were tested on spontaneous alternation and attentional set-shifting. After behavioral testing, brains were harvested for determination of mature brain-derived neurotrophic factor (BDNF) and thalamic pathology. Results Moderate TD combined with CET, regardless of treatment order, produced significant impairments in spatial memory, cognitive flexibility and reductions in brain plasticity as measured by BDNF levels in the frontal cortex and hippocampus. These alterations are greater than those seen in moderate TD alone and the synergistic effects of moderate TD with CET leads to a unique cognitive profile. However, CET did not exacerbate thalamic pathology seen after moderate TD. Conclusions These data support the emerging theory that subclinical TD during chronic heavy alcohol consumption is critical for the development of significant cognitive impairment associated with ARBD. PMID:26419807

  1. Development of 3D carbon nanotube interdigitated finger electrodes on polymer substrate for flexible capacitive sensor application.

    Science.gov (United States)

    Hu, Chih-Fan; Wang, Jhih-Yu; Liu, Yu-Chia; Tsai, Ming-Han; Fang, Weileun

    2013-11-08

    This study reports a novel approach to the implementation of 3D carbon nanotube (CNT) interdigitated finger electrodes on flexible polymer, and the detection of strain, bending curvature, tactile force and proximity distance are demonstrated. The merits of the presented CNT-based flexible sensor are as follows: (1) the silicon substrate is patterned to enable the formation of 3D vertically aligned CNTs on the substrate surface; (2) polymer molding on the silicon substrate with 3D CNTs is further employed to transfer the 3D CNTs to the flexible polymer substrate; (3) the CNT-polymer composite (~70 μm in height) is employed to form interdigitated finger electrodes to increase the sensing area and initial capacitance; (4) other structures such as electrical routings, resistors and mechanical supporters are also available using the CNT-polymer composite. The preliminary fabrication results demonstrate a flexible capacitive sensor with 50 μm high CNT interdigitated electrodes on a poly-dimethylsiloxane substrate. The tests show that the typical capacitance change is several dozens of fF and the gauge factor is in the range of 3.44-4.88 for strain and bending curvature measurement; the sensitivity of the tactile sensor is 1.11% N(-1); a proximity distance near 2 mm away from the sensor can be detected.

  2. Static and high frequency magnetic properties of FeGa thin films deposited on convex flexible substrates

    Science.gov (United States)

    Yu, Ying; Zhan, Qingfeng; Wei, Jinwu; Wang, Jianbo; Dai, Guohong; Zuo, Zhenghu; Zhang, Xiaoshan; Liu, Yiwei; Yang, Huali; Zhang, Yao; Xie, Shuhong; Wang, Baomin; Li, Run-Wei

    2015-04-01

    Magnetostrictive FeGa thin films were deposited on the bowed flexible polyethylene terephthalate (PET) substrates, which were fixed on the convex mold. A compressive stress was induced in FeGa films when the PET substrates were shaped from convex to flat. Due to the effect of magnetostriction, FeGa films exhibit an obvious in-plane uniaxial magnetic anisotropy which could be enhanced by increasing the applied pre-strains on the substrates during growth. Consequently, the ferromagnetic resonance frequency of the films was significantly increased, but the corresponding initial permeability was decreased. Moreover, the films with pre-strains less than 0.78% exhibit a working bandwidth of microwave absorption about 2 GHz. Our investigations demonstrated a convenient method via the pre-strained substrates to tune the high frequency properties of magnetic thin films which could be applied in flexible microwave devices.

  3. Static and high frequency magnetic properties of FeGa thin films deposited on convex flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Ying [Key Laboratory of Magnetic Materials and Devices and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105 (China); Zhan, Qingfeng, E-mail: zhanqf@nimte.ac.cn, E-mail: runweili@nimte.ac.cn; Dai, Guohong; Zuo, Zhenghu; Zhang, Xiaoshan; Liu, Yiwei; Yang, Huali; Zhang, Yao; Wang, Baomin; Li, Run-Wei, E-mail: zhanqf@nimte.ac.cn, E-mail: runweili@nimte.ac.cn [Key Laboratory of Magnetic Materials and Devices and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wei, Jinwu; Wang, Jianbo [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Xie, Shuhong [Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105 (China)

    2015-04-20

    Magnetostrictive FeGa thin films were deposited on the bowed flexible polyethylene terephthalate (PET) substrates, which were fixed on the convex mold. A compressive stress was induced in FeGa films when the PET substrates were shaped from convex to flat. Due to the effect of magnetostriction, FeGa films exhibit an obvious in-plane uniaxial magnetic anisotropy which could be enhanced by increasing the applied pre-strains on the substrates during growth. Consequently, the ferromagnetic resonance frequency of the films was significantly increased, but the corresponding initial permeability was decreased. Moreover, the films with pre-strains less than 0.78% exhibit a working bandwidth of microwave absorption about 2 GHz. Our investigations demonstrated a convenient method via the pre-strained substrates to tune the high frequency properties of magnetic thin films which could be applied in flexible microwave devices.

  4. Laser Direct Write micro-fabrication of large area electronics on flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zacharatos, F.; Makrygianni, M. [National Technical University of Athens, Physics Department, Zografou Campus, 15780 (Greece); Geremia, R.; Biver, E.; Karnakis, D. [Oxford Lasers Ltd, Unit 8 Moorbrook Park, Oxfordshire OX11 7HP (United Kingdom); Leyder, S.; Puerto, D.; Delaporte, P. [Aix-Marseille University, CNRS, LP3 – UMR 7341, 13288 Marseille Cedex 9 (France); Zergioti, I., E-mail: zergioti@central.ntua.gr [National Technical University of Athens, Physics Department, Zografou Campus, 15780 (Greece)

    2016-06-30

    Highlights: • Laser Direct Writing of metallic patterns with a minimum feature size of 1 μm. • Selective Laser Ablation of 50 nm thick metal films on flexible substrates. • Selective Laser sintering resulting in an electrical resistivity of 9 μΩ cm. • Laser fabrication of interdigitated electrodes for sensor applications. - Abstract: To date, Laser Direct Write (LDW) techniques, such as Laser Induced Forward Transfer (LIFT), selective laser ablation and selective laser sintering of metal nanoparticle (NP) ink layers are receiving growing attention for the printing of uniform and well-defined conductive patterns with resolution down to 10 μm. For flexible substrates in particular, selective laser sintering of such NP patterns has been widely applied, as a low temperature and high resolution process compatible with large area electronics. In this work, LDW of silver NP inks has been carried out on polyethylene-terephthalate (PET), polyethylene-naphthalate (PEN) and polyimide (PI) substrates to achieve low electrical resistivity electrodes. In more detail, high speed short pulsed (picosecond and nanosecond) lasers with repetition rates up to 1 MHz were used to print (LIFT) metal NP inks. We thus achieved uniform and continuous patterns with a minimum feature size of 1 μm and a total footprint larger than 1 cm{sup 2}. Next, the printed patterns were laser sintered with ns pulses at 532 nm over a wide laser fluence window, resulting in an electrical resistivity of 10 μΩ cm. We carried out spatial beam shaping experiments to achieve a top-hat laser intensity profile and employed selective laser ablation of thin films (thickness on the order of 100 nm) to produce silver micro-electrodes with a resolution on the order of 10 μm and a low line edge roughness. Laser sintering was combined with laser ablation to constitute a fully autonomous micro-patterning technique of metallic micro-features, with a 10 μm resolution and geometrical characteristics tuned for

  5. Controlled buckling behavior of patterned oxide structures on compliant substrates for flexible optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Bejitual, T.S.; Morris, N.J.; Cairns, D.R.; Sierros, K.A., E-mail: kostas.sierros@mail.wvu.edu

    2013-12-31

    There is currently a great interest to design and fabricate novel flexible devices for solar cell, solid-state lighting, biomedical and energy harvesting applications. Such devices require the use of electrode components. Desired electrodes must exhibit structural integrity, low electrical resistivity and, in most cases, high optical transparency in the visible range. Despite growing efforts to replace them, transparent conducting oxide layers deposited on polymer substrates are still enjoying a dominant role as the electrode component. This is because of their excellent combination of electrical and optical properties. However, their performance when they are subjected to externally-applied mechanical stresses is limited. Such performance has been extensively investigated for the case of continuous brittle oxide films on polymer substrates. However, there is relatively little work reported to date on the mechanical behavior of patterned conducting layers on compliant substrates. In this study we report on the mechanical behavior of various patterned indium tin oxide shapes and sizes on polyethylene terephthalate. Micron-sized shapes include squares, circles, and zigzag-based structures. Controlled buckling experiments are performed in-situ using an optical microscope in order to monitor critical strains and potential failure mechanisms. In addition, ITO electrical resistance changes are continuously monitored during deformation. Furthermore, ex-situ characterization of the tested surfaces using scanning electron microscopy is conducted. Higher crack onset values are observed for the smaller size patterns. Also, square-shaped patterns are found to exhibit the lowest crack onset values. SEM observations suggest cracking-driven and buckling-driven delamination during ITO tensile and compressive buckling mode respectively. In both cases, failure is observed to initiate from the pattern edges. - Highlights: • In-situ experimental analysis of various patterned shapes

  6. Physical encapsulation and controlled assembly of lipid bilayers within flexible substrates

    Science.gov (United States)

    Sarles, Stephen A.; Leo, Donald J.

    2010-04-01

    Biomolecular networks formed from droplet interface bilayers (DIB) use principles of phase separation and molecular self-assembly to create a new type of functional material. The original DIB embodiment consists of lipid-encased aqueous droplets surrounding by a large volume of oil contained in a shallow well. However, recent results have shown that, by reducing the amount of oil that separates the droplets from the supporting substrate, physically-encapsulated DIBs display increased durability and portability. In this paper we extend the concept of encapsulated biomolecular networks to one in which phase separation and molecular self-assembly occur entirely within internally-structured reservoirs of a solid material. Flexible substrates with 200μm wideby- 200μm deep internal microchannels for holding the aqueous and oil phases are fabricated from Sylgard 184 polydimethylsiloxane (PDMS) using soft-lithography microfabrication techniques. Narrowed apertures along the microchannels enable the use of the regulated attachment method (RAM) to subdivide and reattach lipid-encased aqueous volumes contained within the material with an applied external force. The use of perfluorodecalin, a fluorocarbon oil, instead of hexadecane eliminates absorption of the oil phase into the PDMS bulk while a silanization surface treatment of the internal channel walls maximizes wetting by the oil phase to retain a thin layer of oil within the channels to provide a fluid oil/water interface around the aqueous volumes. High-quality 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPHPC) lipid bilayers formed within the prototype substrates have electrical resistance between 1-100GΩ, enabling the measurement of single and few-channel recordings of alpha-hemolysin (αHL) and alamethicin proteins incorporated into the bilayers.

  7. Fully Printed High-Frequency Phased-Array Antenna on Flexible Substrate

    Science.gov (United States)

    Chen, Yihong; Lu, Xuejun

    2010-01-01

    To address the issues of flexible electronics needed for surface-to-surface, surface-to-orbit, and back-to-Earth communications necessary for manned exploration of the Moon, Mars, and beyond, a room-temperature printing process has been developed to create active, phased-array antennas (PAAs) on a flexible Kapton substrate. Field effect transistors (FETs) based on carbon nanotubes (CNTs), with many unique physical properties, were successfully proven feasible for phased-array antenna systems. The carrier mobility of an individual CNT is estimated to be at least 100,000 sq cm/V(dot)s. The CNT network in solution has carrier mobility as high as 46,770 sq cm/V(dot)s, and has a large current-density carrying capacity of approx. 1,000 mA/sq cm , which corresponds to a high carrying power of over 2,000 mW/ sq cm. Such high carrier mobility, and large current carrying capacity, allows the achievement of high-speed (>100 GHz), high-power, flexible electronic circuits that can be monolithically integrated on NASA s active phasedarray antennas for various applications, such as pressurized rovers, pressurized habitats, and spacesuits, as well as for locating beacon towers for lunar surface navigation, which will likely be performed at S-band and attached to a mobile astronaut. A fully printed 2-bit 2-element phasedarray antenna (PAA) working at 5.6 GHz, incorporating the CNT FETs as phase shifters, is demonstrated. The PAA is printed out at room temperature on 100-mm thick Kapton substrate. Four CNT FETs are printed together with microstrip time delay lines to function as a 2-bit phase shifter. The FET switch exhibits a switching speed of 0.2 ns, and works well for a 5.6-GHz RF signal. The operating frequency is measured to be 5.6 GHz, versus the state-of-the-art flexible FET operating frequency of 52 MHz. The source-drain current density is measured to be over 1,000 mA/sq cm, while the conventional organic FETs, and single carbon nanotube-based FETs, are typically in the m

  8. Flexible diamond-like carbon films on rubber : Friction and the effect of viscoelastic deformation of rubber substrates

    NARCIS (Netherlands)

    Pei, Y. T.; Martinez-Martinez, D.; van der Pal, J. P.; Bui, X. L.; Zhou, X. B.; De Hosson, J. Th. M.

    2012-01-01

    This paper focuses on the frictional behavior of flexible diamond-like carbon (DLC) film-coated hydrogenated nitrile butadiene rubber. By making use of the substantial thermal mismatch between DLC film and rubber substrate, a dense network of cracks forms in the DLC films and contributes to flexibil

  9. Low temperature deposition of polycrystalline silicon thin films on a flexible polymer substrate by hot wire chemical vapor deposition

    Science.gov (United States)

    Lee, Sang-hoon; Jung, Jae-soo; Lee, Sung-soo; Lee, Sung-bo; Hwang, Nong-moon

    2016-11-01

    For the applications such as flexible displays and solar cells, the direct deposition of crystalline silicon films on a flexible polymer substrate has been a great issue. Here, we investigated the direct deposition of polycrystalline silicon films on a polyimide film at the substrate temperature of 200 °C. The low temperature deposition of crystalline silicon on a flexible substrate has been successfully made based on two ideas. One is that the Si-Cl-H system has a retrograde solubility of silicon in the gas phase near the substrate temperature. The other is the new concept of non-classical crystallization, where films grow by the building block of nanoparticles formed in the gas phase during hot-wire chemical vapor deposition (HWCVD). The total amount of precipitation of silicon nanoparticles decreased with increasing HCl concentration. By adding HCl, the amount and the size of silicon nanoparticles were reduced remarkably, which is related with the low temperature deposition of silicon films of highly crystalline fraction with a very thin amorphous incubation layer. The dark conductivity of the intrinsic film prepared at the flow rate ratio of RHCl=[HCl]/[SiH4]=3.61 was 1.84×10-6 Scm-1 at room temperature. The Hall mobility of the n-type silicon film prepared at RHCl=3.61 was 5.72 cm2 V-1s-1. These electrical properties of silicon films are high enough and could be used in flexible electric devices.

  10. Laser-Assisted Simultaneous Transfer and Patterning of Vertically Aligned Carbon Nanotube Arrays on Polymer Substrates for Flexible Devices

    KAUST Repository

    In, Jung Bin

    2012-09-25

    We demonstrate a laser-assisted dry transfer technique for assembling patterns of vertically aligned carbon nanotube arrays on a flexible polymeric substrate. A laser beam is applied to the interface of a nanotube array and a polycarbonate sheet in contact with one another. The absorbed laser heat promotes nanotube adhesion to the polymer in the irradiated regions and enables selective pattern transfer. A combination of the thermal transfer mechanism with rapid direct writing capability of focused laser beam irradiation allows us to achieve simultaneous material transfer and direct micropatterning in a single processing step. Furthermore, we demonstrate that malleability of the nanotube arrays transferred onto a flexible substrate enables post-transfer tailoring of electric conductance by collapsing the aligned nanotubes in different directions. This work suggests that the laser-assisted transfer technique provides an efficient route to using vertically aligned nanotubes as conductive elements in flexible device applications. © 2012 American Chemical Society.

  11. Nanocrystalline cellulose applied simultaneously as the gate dielectric and the substrate in flexible field effect transistors.

    Science.gov (United States)

    Gaspar, D; Fernandes, S N; de Oliveira, A G; Fernandes, J G; Grey, P; Pontes, R V; Pereira, L; Martins, R; Godinho, M H; Fortunato, E

    2014-03-07

    Cotton-based nanocrystalline cellulose (NCC), also known as nanopaper, one of the major sources of renewable materials, is a promising substrate and component for producing low cost fully recyclable flexible paper electronic devices and systems due to its properties (lightweight, stiffness, non-toxicity, transparency, low thermal expansion, gas impermeability and improved mechanical properties).Here, we have demonstrated for the first time a thin transparent nanopaper-based field effect transistor (FET) where NCC is simultaneously used as the substrate and as the gate dielectric layer in an 'interstrate' structure, since the device is built on both sides of the NCC films; while the active channel layer is based on oxide amorphous semiconductors, the gate electrode is based on a transparent conductive oxide.Such hybrid FETs present excellent operating characteristics such as high channel saturation mobility (>7 cm(2) V (-1) s(-1)), drain-source current on/off modulation ratio higher than 10(5), enhancement n-type operation and subthreshold gate voltage swing of 2.11 V/decade. The NCC film FET characteristics have been measured in air ambient conditions and present good stability, after two weeks of being processed, without any type of encapsulation or passivation layer. The results obtained are comparable to ones produced for conventional cellulose paper, marking this out as a promising approach for attaining high-performance disposable electronics such as paper displays, smart labels, smart packaging, RFID (radio-frequency identification) and point-of-care systems for self-analysis in bioscience applications, among others.

  12. Nanocrystalline cellulose applied simultaneously as the gate dielectric and the substrate in flexible field effect transistors

    Science.gov (United States)

    Gaspar, D.; Fernandes, S. N.; de Oliveira, A. G.; Fernandes, J. G.; Grey, P.; Pontes, R. V.; Pereira, L.; Martins, R.; Godinho, M. H.; Fortunato, E.

    2014-03-01

    Cotton-based nanocrystalline cellulose (NCC), also known as nanopaper, one of the major sources of renewable materials, is a promising substrate and component for producing low cost fully recyclable flexible paper electronic devices and systems due to its properties (lightweight, stiffness, non-toxicity, transparency, low thermal expansion, gas impermeability and improved mechanical properties). Here, we have demonstrated for the first time a thin transparent nanopaper-based field effect transistor (FET) where NCC is simultaneously used as the substrate and as the gate dielectric layer in an ‘interstrate’ structure, since the device is built on both sides of the NCC films; while the active channel layer is based on oxide amorphous semiconductors, the gate electrode is based on a transparent conductive oxide. Such hybrid FETs present excellent operating characteristics such as high channel saturation mobility (>7 cm2 V -1 s-1), drain-source current on/off modulation ratio higher than 105, enhancement n-type operation and subthreshold gate voltage swing of 2.11 V/decade. The NCC film FET characteristics have been measured in air ambient conditions and present good stability, after two weeks of being processed, without any type of encapsulation or passivation layer. The results obtained are comparable to ones produced for conventional cellulose paper, marking this out as a promising approach for attaining high-performance disposable electronics such as paper displays, smart labels, smart packaging, RFID (radio-frequency identification) and point-of-care systems for self-analysis in bioscience applications, among others.

  13. Laser Direct Write micro-fabrication of large area electronics on flexible substrates

    Science.gov (United States)

    Zacharatos, F.; Makrygianni, M.; Geremia, R.; Biver, E.; Karnakis, D.; Leyder, S.; Puerto, D.; Delaporte, P.; Zergioti, I.

    2016-06-01

    To date, Laser Direct Write (LDW) techniques, such as Laser Induced Forward Transfer (LIFT), selective laser ablation and selective laser sintering of metal nanoparticle (NP) ink layers are receiving growing attention for the printing of uniform and well-defined conductive patterns with resolution down to 10 μm. For flexible substrates in particular, selective laser sintering of such NP patterns has been widely applied, as a low temperature and high resolution process compatible with large area electronics. In this work, LDW of silver NP inks has been carried out on polyethylene-terephthalate (PET), polyethylene-naphthalate (PEN) and polyimide (PI) substrates to achieve low electrical resistivity electrodes. In more detail, high speed short pulsed (picosecond and nanosecond) lasers with repetition rates up to 1 MHz were used to print (LIFT) metal NP inks. We thus achieved uniform and continuous patterns with a minimum feature size of 1 μm and a total footprint larger than 1 cm2. Next, the printed patterns were laser sintered with ns pulses at 532 nm over a wide laser fluence window, resulting in an electrical resistivity of 10 μΩ cm. We carried out spatial beam shaping experiments to achieve a top-hat laser intensity profile and employed selective laser ablation of thin films (thickness on the order of 100 nm) to produce silver micro-electrodes with a resolution on the order of 10 μm and a low line edge roughness. Laser sintering was combined with laser ablation to constitute a fully autonomous micro-patterning technique of metallic micro-features, with a 10 μm resolution and geometrical characteristics tuned for interdigitated electrodes for sensor applications.

  14. Low temperature growth of ZnO nanostructures on flexible polystyrene substrates for optical, photoluminescence and wettability applications

    Science.gov (United States)

    Durga Prasad, Muvva; Pasha Shaik, Ummar; Madhurima, V.; Ghanashyam Krishna, M.

    2016-08-01

    The growth of ZnO nanostructures on flexible polystyrene substrates by a simple vacuum thermal evaporation process is reported. The ZnO films are deposited on polystyrene surfaces of 6 μm thickness which are initially anchored on glass substrates. The as-deposited films are annealed at temperatures up to 180 °C for 6-24 h after which the polystyrene is lifted off from the glass substrates to yield nanostructured films on a flexible substrate. At 180 °C there is transformation of the partially oxidized as-deposited films into nearly stoichiometric ZnO. This is accompanied by the formation of nanostructures such as nanorods, nanotubes and nanodoughnuts. The films, which were 50-200 nm in thickness, are polycrystalline in nature and also exhibit Zn/ZnO core-shell structures under favorable conditions. The nanostructures exhibit transmission greater than 80% in the visible and near infrared regions and band gaps of the order of 4 eV. The films exhibit strong blue photoluminescence and the peak position as well as intensity of emission can be tuned by varying thickness and annealing conditions. To demonstrate the flexibility, the ZnO coated polystyrene substrates were wrapped around a LED to show UV blocking property. Wettability studies indicate that films are hydrophobic with water contact angles between 92°-95°.

  15. Artificial neuron synapse transistor based on silicon nanomembrane on plastic substrate

    Science.gov (United States)

    Liu, Minjie; Huang, Gaoshan; Feng, Ping; Guo, Qinglei; Shao, Feng; Tian, Ziao; Li, Gongjin; Wan, Qing; Mei, Yongfeng

    2017-06-01

    Silicon nanomembrane (SiNM) transistors gated by chitosan membrane were fabricated on plastic substrate to mimic synapse behaviors. The device has both a bottom proton gate (BG) and multiple side gates (SG). Electrical transfer properties of BG show hysteresis curves different from those of typical SiO2 gate dielectric. Synaptic behaviors and functions by linear accumulation and release of protons have been mimicked on this device: excitatory post-synaptic current (EPSC) and paired pulse facilitation behavior of biological synapses were mimicked and the paired-pulse facilitation index could be effectively tuned by the spike interval applied on the BG. Synaptic behaviors and functions, including short-term memory and long-term memory, were also experimentally demonstrated in BG mode. Meanwhile, spiking logic operation and logic modulation were realized in SG mode. Project supported by the National Natural Science Foundation of China (No. 51322201), the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20120071110025), and Science and Technology Commission of Shanghai Municipality (No. 14JC1400200).

  16. The Role of p38 MAPK and Its Substrates in Neuronal Plasticity and Neurodegenerative Disease

    Directory of Open Access Journals (Sweden)

    Sônia A. L. Corrêa

    2012-01-01

    Full Text Available A significant amount of evidence suggests that the p38-mitogen-activated protein kinase (MAPK signalling cascade plays a crucial role in synaptic plasticity and in neurodegenerative diseases. In this review we will discuss the cellular localisation and activation of p38 MAPK and the recent advances on the molecular and cellular mechanisms of its substrates: MAPKAPK 2 (MK2 and tau protein. In particular we will focus our attention on the understanding of the p38 MAPK-MK2 and p38 MAPK-tau activation axis in controlling neuroinflammation, actin remodelling and tau hyperphosphorylation, processes that are thought to be involved in normal ageing as well as in neurodegenerative diseases. We will also give some insight into how elucidating the precise role of p38 MAPK-MK2 and p38 MAPK-tau signalling cascades may help to identify novel therapeutic targets to slow down the symptoms observed in neurodegenerative diseases such as Alzheimer's and Parkinson's disease.

  17. Preparation of water-resistant antifog hard coatings on plastic substrate.

    Science.gov (United States)

    Chang, Chao-Ching; Huang, Feng-Hsi; Chang, Hsu-Hsien; Don, Trong-Ming; Chen, Ching-Chung; Cheng, Liao-Ping

    2012-12-11

    A novel water resistant antifog (AF) coating for plastic substrates was developed, which has a special hydrophilic/hydrophobic bilayer structure. The bottom layer, acting both as a mechanical support and a hydrophobic barrier against water penetration, is an organic-inorganic composite comprising colloidal silica embedded in a cross-linked network of dipentaethritol hexaacrylate (DPHA). Atop this layer, an AF coating is applied, which incorporates a superhydrophilic species synthesized from Tween-20 (surfactant), isophorone diisocyanate (coupling agent), and 2-hydroxyethyl methacrylate (monomer). Various methods, e.g., FTIR, SEM, AFM, contact angle, and steam test, were employed to characterize the prepared AF coatings. The results indicated that the size and the continuity of the hydrophilic domains on the top surface increased with increasing added amount of T20, however, at the expense of hardness, adhesiveness, and water resistivity. The optimal T20 content was found to be 10 wt %, at which capacity the resultant AF coating was transparent and wearable (5H, hardness) and could be soaked in water for 7 days at 25 °C without downgrading of its AF capability.

  18. Porous honeycomb structures formed from interconnected MnO2 sheets on CNT-coated substrates for flexible all-solid-state supercapacitors

    Science.gov (United States)

    Ko, Wen-Yin; Chen, You-Feng; Lu, Ke-Ming; Lin, Kuan-Jiuh

    2016-01-01

    The use of lightweight and easily-fabricated MnO2/carbon nanotube (CNT)-based flexible networks as binder-free electrodes and a polyvinyl alcohol/H2SO4 electrolyte for the formation of stretchable solid-state supercapacitors was examined. The active electrodes were fabricated from 3D honeycomb porous MnO2 assembled from cross-walled and interconnected sheet-architectural MnO2 on CNT-based plastic substrates (denoted as honeycomb MnO2/CNT textiles).These substrates were fabricated through a simple two-step procedure involving the coating of multi-walled carbon nanotubes (MWCNTs) onto commercial textiles by a dipping-drying process and subsequent electrodeposition of the interconnected MnO2 sheets onto the MWCNT-coated textile. With such unique MnO2 architectures integrated onto CNT flexible films, good performance was achieved with a specific capacitance of 324 F/g at 0.5 A/g. A maximum energy density of 7.2 Wh/kg and a power density as high as 3.3 kW/kg were exhibited by the honeycomb MnO2/CNT network device, which is comparable to the performance of other carbon-based and metal oxide/carbon-based solid-state supercapacitor devices. Specifically, the long-term cycling stability of this material is excellent, with almost no loss of its initial capacitance and good Coulombic efficiency of 82% after 5000 cycles. These impressive results identify these materials as a promising candidate for use in environmentally friendly, low-cost, and high-performance flexible energy-storage devices.

  19. Superhydrophilic Antireflective Periodic Mesoporous Organosilica Coating on Flexible Polyimide Substrate with Strong Abrasion-Resistance.

    Science.gov (United States)

    Wang, Jing; Zhang, Cong; Yang, Chunming; Zhang, Ce; Wang, Mengchao; Zhang, Jing; Xu, Yao

    2017-02-15

    Superhydrophilic antireflective periodic mesoporous organosilica (PMO) coating was prepared on flexible polyimide substrate via solvent-evaporation-induced self-assembly (SEISA) method, in which tetraethoxysilane (TEOS) and a special bridged silsesquioxane were used as reactants. The bridged silsesquioxane, EG-BSQ, was synthesized through the stoichiometric reaction between 3-glycidoxyporpyltrimethoxysilane (GPTMS) and ethylene diamine (EDA). Under the influence of surfactant, TEOS and EG-BSQ co-condensed and enclosed the ordered mesporous in the coating. The results of grazing-incidence small-angle X-ray scattering (GISAXS) and the transmission electron microscope (TEM) indicated that the mesopores belonged to a Fmmm orthorhombic symmetry structure. With increasing EG-BSQ concentration, the mesoporous structure in the PMO coating becomes more and more disordered because silica mesopore walls shrunk or collapsed during calcination and consequently the refractive index of PMO coating became larger. The antireflective (AR) PMO coating showed an optical transmittance of 99.54% on polyimide (PI) much higher than the 88.68% of bare PI. The water contact angle of PMO coating was less than 9.0°, which indicated the AR PMO coating was superhydrophilic. Moreover, the PMO coating showed an excellent mechanical property, the transmittance of the PMO coating displayed a very low loss of 0.1% after abrasion of 25 cycles by CS-10F wearaser.

  20. Tensile characteristics of metal nanoparticle films on flexible polymer substrates for printed electronics applications

    Science.gov (United States)

    Kim, Sanghyeok; Won, Sejeong; Sim, Gi-Dong; Park, Inkyu; Lee, Soon-Bok

    2013-03-01

    Metal nanoparticle solutions are widely used for the fabrication of printed electronic devices. The mechanical properties of the solution-processed metal nanoparticle thin films are very important for the robust and reliable operation of printed electronic devices. In this paper, we report the tensile characteristics of silver nanoparticle (Ag NP) thin films on flexible polymer substrates by observing the microstructures and measuring the electrical resistance under tensile strain. The effects of the annealing temperatures and periods of Ag NP thin films on their failure strains are explained with a microstructural investigation. The maximum failure strain for Ag NP thin film was 6.6% after initial sintering at 150 °C for 30 min. Thermal annealing at higher temperatures for longer periods resulted in a reduction of the maximum failure strain, presumably due to higher porosity and larger pore size. We also found that solution-processed Ag NP thin films have lower failure strains than those of electron beam evaporated Ag thin films due to their highly porous film morphologies.

  1. MEMS flexible artificial basilar membrane fabricated from piezoelectric aluminum nitride on an SU-8 substrate

    Science.gov (United States)

    Jang, Jongmoon; Jang, Jeong Hun; Choi, Hongsoo

    2017-07-01

    In this paper, we present a flexible artificial basilar membrane (FABM) that mimics the passive mechanical frequency selectivity of the basilar membrane. The FABM is composed of a cantilever array made of piezoelectric aluminum nitride (AlN) on an SU-8 substrate. We analyzed the orientations of the AlN crystals using scanning electron microscopy and x-ray diffraction. The AIN crystals are oriented in the c-axis (0 0 2) plane and effective piezoelectric coefficient was measured as 3.52 pm V-1. To characterize the frequency selectivity of the FABM, mechanical displacements were measured using a scanning laser Doppler vibrometer. When electrical and acoustic stimuli were applied, the measured resonance frequencies were in the ranges of 663.0-2369 Hz and 659.4-2375 Hz, respectively. These results demonstrate that the mechanical frequency selectivity of this piezoelectric FABM is close to the human communication frequency range (300-3000 Hz), which is a vital feature of potential auditory prostheses.

  2. Multivariable passive RFID vapor sensors: roll-to-roll fabrication on a flexible substrate.

    Science.gov (United States)

    Potyrailo, Radislav A; Burns, Andrew; Surman, Cheryl; Lee, D J; McGinniss, Edward

    2012-06-21

    We demonstrate roll-to-roll (R2R) fabrication of highly selective, battery-free radio frequency identification (RFID) sensors on a flexible polyethylene terephthalate (PET) polymeric substrate. Selectivity of our developed RFID sensors is provided by measurements of their resonance impedance spectra, followed by the multivariate analysis of spectral features, and correlation of these spectral features to the concentrations of vapors of interest. The multivariate analysis of spectral features also provides the ability for the rejection of ambient interferences. As a demonstration of our R2R fabrication process, we employed polyetherurethane (PEUT) as a "classic" sensing material, extruded this sensing material as 25, 75, and 125-μm thick films, and thermally laminated the films onto RFID inlays, rapidly producing approximately 5000 vapor sensors. We further tested these RFID vapor sensors for their response selectivity toward several model vapors such as toluene, acetone, and ethanol as well as water vapor as an abundant interferent. Our RFID sensing concept features 16-bit resolution provided by the sensor reader, granting a highly desired independence from costly proprietary RFID memory chips with a low-resolution analog input. Future steps are being planned for field-testing of these sensors in numerous conditions.

  3. Synthesis of silicon nanocomposite for printable photovoltaic devices on flexible substrate

    Science.gov (United States)

    Odo, E. A.; Faremi, A. A.

    2017-06-01

    Renewed interest has been established in the preparation of silicon nanoparticles for electronic device applications. In this work, we report on the production of silicon powders using a simple ball mill and of silicon nanocomposite ink for screen-printable photovoltaic device on a flexible substrate. Bulk single crystalline silicon was milled for 25 h in the ball mill. The structural properties of the produced silicon nanoparticles were investigated using X-ray diffraction (XRD) and transmission electron microscopy. The results show that the particles remained highly crystalline, though transformed from their original single crystalline state to polycrystalline. The elemental composition using energy dispersive X-ray florescence spectroscopy (EDXRF) revealed that contamination from iron (Fe) and chromium (Cr) of the milling media and oxygen from the atmosphere were insignificant. The size distribution of the nanoparticles follows a lognormal pattern that ranges from 60 nm to about 1.2 μm and a mean particle size of about 103 nm. Electrical characterization of screen-printed PN structures of the nanocomposite formed by embedding the powder into a suitable water-soluble polymer on Kapton sheet reveals an enhanced photocurrent transport resulting from photo-induced carrier generation in the depletion region with energy greater that the Schottky barrier height at the metal-composite interface.

  4. Tensile characteristics of metal nanoparticle films on flexible polymer substrates for printed electronics applications.

    Science.gov (United States)

    Kim, Sanghyeok; Won, Sejeong; Sim, Gi-Dong; Park, Inkyu; Lee, Soon-Bok

    2013-03-01

    Metal nanoparticle solutions are widely used for the fabrication of printed electronic devices. The mechanical properties of the solution-processed metal nanoparticle thin films are very important for the robust and reliable operation of printed electronic devices. In this paper, we report the tensile characteristics of silver nanoparticle (Ag NP) thin films on flexible polymer substrates by observing the microstructures and measuring the electrical resistance under tensile strain. The effects of the annealing temperatures and periods of Ag NP thin films on their failure strains are explained with a microstructural investigation. The maximum failure strain for Ag NP thin film was 6.6% after initial sintering at 150 °C for 30 min. Thermal annealing at higher temperatures for longer periods resulted in a reduction of the maximum failure strain, presumably due to higher porosity and larger pore size. We also found that solution-processed Ag NP thin films have lower failure strains than those of electron beam evaporated Ag thin films due to their highly porous film morphologies.

  5. Mechanical properties of amorphous indium–gallium–zinc oxide thin films on compliant substrates for flexible optoelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, D.W., E-mail: DWM172@bham.ac.uk [University of Birmingham, School of Metallurgy and Materials, Edgbaston, Birmingham, B15 2TT (United Kingdom); Waddingham, R.; Flewitt, A.J. [University of Cambridge, Electrical Engineering Division, Department of Engineering, J J Thomson Avenue, Cambridge CB3 0FA,United Kingdom (United Kingdom); Sierros, K.A. [West Virginia University, Mechanical & Aerospace Engineering, Morgantown, WV 26506 (United States); Bowen, J. [Open University, Department of Engineering and Innovation, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Kukureka, S.N. [University of Birmingham, School of Metallurgy and Materials, Edgbaston, Birmingham, B15 2TT (United Kingdom)

    2015-11-02

    Amorphous indium–gallium–zinc-oxide (a-IGZO) thin films were deposited using RF magnetron sputtering on polyethylene naphthalate (PEN) and polyethylene terephthalate (PET) flexible substrates and their mechanical flexibility investigated using uniaxial tensile and buckling tests coupled with in situ optical microscopy. The uniaxial fragmentation test demonstrated that the crack onset strain of the IGZO/PEN was ~ 2.9%, which is slightly higher than that of IGZO/PET. Also, uniaxial tensile crack density analysis suggests that the saturated crack spacing of the film is strongly dependent on the mechanical properties of the underlying polymer substrate. Buckling test results suggest that the crack onset strain (equal to ~ 1.2%, of the IGZO/polymer samples flexed in compression to ~ 5.7 mm concave radius of curvature) is higher than that of the samples flexed with the film being in tension (convex bending) regardless whether the substrate is PEN or PET. The saturated crack density of a-IGZO film under the compression buckling mode is smaller than that of the film under the tensile buckling mode. This could be attributed to the fact that the tensile stress encouraged this crack formation originating from surface defects in the coating. It could also be due to the buckling delamination of the thin coating from the substrate at a lower strain than that at which a crack initiates during flexing in compression. These results provide useful information on the mechanical reliability of a-IGZO films for the development of flexible electronics. - Highlights: • Mechanical flexibility of IGZO thin films investigated by uniaxial tensile and buckling tests • Uniaxial fragmentation gives crack onset strain for IGZO/PEN of 2.9% (higher than for IGZO/PET.) • Saturated crack spacing strongly dependent on mechanical properties of polymer substrate • Crack onset strain in concave bending higher than in convex bending for both substrates.

  6. Medium scale carbon nanotube thin film integrated circuits on flexible plastic substrates

    Science.gov (United States)

    Rogers, John A; Cao, Qing; Alam, Muhammad; Pimparkar, Ninad

    2015-02-03

    The present invention provides device components geometries and fabrication strategies for enhancing the electronic performance of electronic devices based on thin films of randomly oriented or partially aligned semiconducting nanotubes. In certain aspects, devices and methods of the present invention incorporate a patterned layer of randomly oriented or partially aligned carbon nanotubes, such as one or more interconnected SWNT networks, providing a semiconductor channel exhibiting improved electronic properties relative to conventional nanotubes-based electronic systems.

  7. Spin on Dopants for High-Performance Single-Crystal Silicon Transistors on Flexible Plastic Substrates

    Science.gov (United States)

    2005-03-23

    Lett. 84, 5398 s2004d. 6Y. Sun and J. A. Rogers, Nano Lett. 4, 1953 s2004d; Y. Sun , D.-Y. Khang , F. Hua, K. Hurley, R. G. Nuzzo, and J. A. Rogers...Transistors, edited by C. R. Kagan and P. Andry sDekker, New York, 2003d. 5E. Menard, K. J. Lee, D.-Y. Khang , R. G. Nuzzo, and J. A. Rogers, Appl. Phys

  8. Ultra-Thin Deformable Silicon Substrates with Lateral Segmentation and Flexible Metal Interconnect

    NARCIS (Netherlands)

    Zoumpouidis, T.; Wang, L.; Bartek, M.; Jansen, K.M.B.; Ernst, L.J.

    2007-01-01

    Our progress in developing technology modules for deformable single-crystalline-silicon electronics is presented in this contribution. Additional deformability/reliability is accomplished by modifications of the previously reported ultra-thin and flexible CIRCONFLEX technology (1). The flexibility

  9. Solution-processable electrochemiluminescent ion gels for flexible, low-voltage, emissive displays on plastic.

    Science.gov (United States)

    Moon, Hong Chul; Lodge, Timothy P; Frisbie, C Daniel

    2014-03-05

    Ion gels comprising ABA triblock copolymers and ionic liquids have received much attention as functional materials in numerous applications, especially as gate dielectrics in organic transistors. Here we have expanded the functionality of ion gels by demonstrating low-voltage, flexible electrochemiluminescent (ECL) devices using patterned ion gels containing redox-active luminophores. The ECL devices consisted only of a 30 μm thick emissive gel and two electrodes and were fabricated on indium tin oxide-coated substrates (e.g., polyester) simply by solution-casting the ECL gel and brush-painting a top Ag electrode. The triblock copolymer employed in the gel was polystyrene-block-poly(methyl methacrylate)-block-polystyrene, where the solvophobic polystyrene end blocks associate into micellar cross-links in the versatile ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMI][TFSI]). An ECL gel containing ~6.25 wt % Ru(bpy)3Cl2 (relative to [EMI][TFSI]) as the luminophore turned on at an AC peak-to-peak voltage as low as 2.6 V (i.e., -1.3 to +1.3 V) and showed a relatively rapid response (sub-ms). The wavelength of maximum emission was 610 nm (red-orange). With the use of an iridium(III) complex, Ir(diFppy)2(bpy)PF6 [diFppy = 2-(2',4'-difluorophenyl)pyridine; bpy = 2,2'-bipyridyl], the emitting color was tuned to a maximum wavelength of 540 nm (green). Moreover, when a blended luminophore system containing a 60:40 mixture of Ru(bpy)3(2+) and Ir(diFppy)2(bpy)(+) was used in the emissive layer, the luminance of red-orange-colored light was enhanced by a factor of 2, which is explained by the generation of the additional excited state Ru(bpy)3(2+)* by a coreactant pathway with Ir(diFppy)2(bpy)(+)* in addition to the usual annihilation pathway. This is the first time that enhanced ECL has been achieved in ion gels (or ionic liquids) using a coreactant. Overall, the results indicate that ECL ion gels are attractive multifunctional materials for

  10. Transferability and Adhesion of Sol-Gel-Derived Crystalline TiO2 Thin Films to Different Types of Plastic Substrates.

    Science.gov (United States)

    Amano, Natsumi; Takahashi, Mitsuru; Uchiyama, Hiroaki; Kozuka, Hiromitsu

    2017-01-31

    Anatase thin films were prepared on various plastic substrates by our recently developed sol-gel transfer technique. Polycarbonate (PC), poly(methyl methacrylate) (PMMA), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyether ether ketone (PEEK), and polyvinylidene chloride (PVDC) were employed as plastic substrates. A Si(100) substrate was first coated with a polyimide (PI)/polyvinylpyrrolidone (PVP) mixture layer, and an alkoxide-derived titania gel film was deposited on it by spin-coating. The resulting titania gel film was heated to 600 °C, during which the PI/PVP layer decomposed and the gel film was converted into a 60 nm thick anatase film. The anatase film was then transferred from the Si(100) substrate to the plastic substrate. This was achieved by heating the plastic/anatase/Si(100) stack in a near-infrared image furnace to 120-350 °C, depending on the type of plastic substrate, under unidirectional pressure. The anatase film cracked during transfer to PE, PP, PEEK, and PVDC substrates but did not crack during transfer to PC, PMMA, and PET substrates. The fraction of the total film area that was successfully transferred was assessed with the aid of image analysis. This fraction tended to be large for plastics with C═O and C-O groups and small for those without these groups. The film/substrate adhesion assessed by cross-cut tape tests also tended to be high for plastics with C═O and C-O groups and low for those without these groups. The adhesion to plastics without C═O or C-O groups could be enhanced and their transfer area fraction increased by oxidizing the native plastic surface by ultraviolet-ozone treatment prior to transfer.

  11. Graphene-Al2O3-silicon heterojunction solar cells on flexible silicon substrates

    Science.gov (United States)

    Ahn, Jaehyun; Chou, Harry; Banerjee, Sanjay K.

    2017-04-01

    The quest of obtaining sustainable, clean energy is an ongoing challenge. While silicon-based solar cells have widespread acceptance in practical commercialization, continuous research is important to expand applicability beyond fixed-point generation to other environments while also improving power conversion efficiency (PCE), stability, and cost. In this work, graphene-on-silicon Schottky junction and graphene-insulator-silicon (GIS) solar cells are demonstrated on flexible, thin foils, which utilize the electrical conductivity and optical transparency of graphene as the top transparent contact. Multi-layer graphene was grown by chemical vapor deposition on Cu-Ni foils, followed by p-type doping with Au nanoparticles and encapsulated in poly(methyl methacrylate), which showed high stability with minimal performance degradation over more than one month under ambient conditions. Bendable silicon film substrates were fabricated by a kerf-less exfoliation process based on spalling, where the silicon film thickness could be controlled from 8 to 35 μm based on the process recipe. This method allows for re-exfoliation from the parent Si wafer and incorporates the process for forming the backside metal contact of the solar cell. GIS cells were made with a thin insulating Al2O3 atomic layer deposited film, where the thin Al2O3 film acts as a tunneling barrier for holes, while simultaneously passivating the silicon surface, increasing the minority carrier lifetime from 2 to 27 μs. By controlling the Al2O3 thickness, an optimized cell with 7.4% power conversion efficiency (PCE) on a 35 μm thick silicon absorber was fabricated.

  12. Application of NiMoNb adhesion layer on plasma-treated polyimide substrate for flexible electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Bang, S.-H.; Kim, K.-K.; Jung, H.-Y.; Kim, T.-H.; Jeon, S.-H. [Metal and Material Technology Group, R and D Center, LS Mtron Ltd., Gyeonggi 431-080 (Korea, Republic of); Seol, Jae-Bok, E-mail: zptkfm20@hanmail.net [Max-Planck-Insititut für Eisenforschung, Max-Planck-Str. 1, D-40237 Düsseldorf (Germany)

    2014-05-02

    A thin film, NiMoNb, was introduced as an adhesion layer between the Cu metal and the insulator polyimide substrate in a flexible Cu-clad laminated structure. Using 90° peel test, we evaluated the peel strength of the system as a function of the thickness of the adhesion layer. An increase in the NiMoNb thickness from 7 to 40 nm enhanced the peel strength of the deposited systems. After plasma treatment by the roll-to-roll method, the multilayer structure showed an outstanding peel strength of ∼ 529 N/m, even after thermal annealing at 150 °C for 168 h. We also studied the role of plasma treatment of the polyimide substrate on the adhesion strength and microstructure of a flexible Cu-clad laminated structure by peel strength, atomic force microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. These experimental observations showed that the plasma-treated polyimide substrate with the deposition of NiMoNb showed the enhanced adhesion of ∼ 656 N/m, because of the change of functional groups, which affected the bonding force and crystallinity of the thin films deposited on polyimide, rather than an increase in the surface roughness. - Highlights: • NiMoNb film on polyimide substrate was employed for higher peel strength. • Plasma-treated substrate enhances the peel strength of multilayer. • Even when annealed at 150 °C, plasma-treated films showed enhanced peel strength.

  13. Effects of Hole-Collecting Buffer Layers and Electrodes on the Performance of Flexible Plastic Organic Photovoltaics

    Directory of Open Access Journals (Sweden)

    Sungho Woo

    2013-01-01

    Full Text Available Here we report the influences of the sheet resistance (Rsheet of a hole-collecting electrode (indium tin oxide, ITO and the conductivity of a hole-collecting buffer layer (poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate, PEDOT:PSS on the device performance of flexible plastic organic photovoltaic (OPV devices. The series resistance (RS of OPV devices steeply increases with increasing Rsheet of the ITO electrode, which leads to a significant decrease of short-circuit current density (JSC and fill factor (FF and power conversion efficiency, while the open-circuit voltage (VOC was almost constant. By applying high-conductivity PEDOT:PSS, the efficiency of OPV devices with high Rsheet values of 160 Ω/□ and 510 Ω/□ is greatly improved, by a factor of 3.5 and 6.5, respectively. These results indicate that the conductivities of ITO and PEDOT:PSS will become more important to consider for manufacturing large-area flexible plastic OPV modules.

  14. Morphological and structural characterization of single-crystal ZnO nanorod arrays on flexible and non-flexible substrates

    Directory of Open Access Journals (Sweden)

    Omar F. Farhat

    2015-03-01

    Full Text Available We report a facile synthesis of zinc oxide (ZnO nanorod arrays using an optimized, chemical bath deposition method on glass, PET and Si substrates. The morphological and structural properties of the ZnO nanorod arrays were investigated using various techniques such as field emission scanning electron microscopy (FESEM and X-ray diffraction (XRD measurements, which revealed the formation of dense ZnO nanorods with a single crystal, hexagonal wurtzite structure. The aspect ratio of the single-crystal ZnO nanorods and the growth rate along the (002 direction was found to be sensitive to the substrate type. The lattice constants and the crystallite size of the fabricated ZnO nanorods were calculated based on the XRD data. The obtained results revealed that the increase in the crystallite size is strongly associated with the growth conditions with a minor dependence on the type of substrate. The Raman spectroscopy measurements confirmed the existence of a compressive stress in the fabricated ZnO nanorods. The obtained results illustrated that the growth of high quality, single-crystal ZnO nanorods can be realized by adjusting the synthesis conditions.

  15. Contribution of molecular flexibility to the elastic-plastic properties of molecular crystal α-RDX

    Science.gov (United States)

    Pal, Anirban; Picu, Catalin R.

    2017-01-01

    We show in this work that the mechanical properties of molecular crystals are strongly affected by the flexibility of the constituent molecules. To this end, we explore several kinematically restrained models of the molecular crystal cyclotrimethylene trinitramine in the α phase. We evaluate the effect of gradually removing the flexibility of the molecule on various crystal-scale parameters such as the elastic constants, the lattice parameters, the thermal expansion coefficients, the stacking fault energy and the critical stress for the motion of a dislocation (the Peierls-Nabarro stress). The values of these parameters evaluated with the fully refined, fully flexible atomistic model of the crystal are taken as reference. It is observed that the elastic constants, the lattice parameters and their dependence on pressure, and the thermal expansion coefficient can be accurately predicted with models that consider the NO2 and CH2 groups rigid, and the N-N bonds and the bonds of the triazine ring inextensible. Eliminating the dihedral flexibility of the ring leads to larger errors. The model in which the entire molecule is considered rigid or is mapped to a blob leads to even larger errors. Only the fully flexible, reference model provides accurate values for the stacking fault energy and the Peierls-Nabarro critical stress. Removing any component of the molecular flexibility leads to large errors in these parameters. These results also provide guidance for the development of coarse grained models of molecular crystals.

  16. Plasticizer migration from cross-linked flexible PVC. 1. Effects on tribology

    Science.gov (United States)

    Pannico, M.; Persico, P.; Ambrogi, V.; Carfagna, C.

    2010-06-01

    Utilization of soft PVC is restricted by plasticizer migration that can affect material properties, as well as its toxicity. Modifying the chemical structure of PVC is one of the most effective tool to reduce the diffusion of plasticizer. In this work, a soft cross-linked PVC was obtained using a difunctional amine, namely isophoron diamine (IPDA) as the cross-linking agent. The gel content (wt %) was evaluated by weighting the insoluble portion obtained through solvent extraction technique. Thermogravimetric analysis (TGA) revealed that cross-linking reactions promote thermal degradation phenomena in the polymer matrix. Tribological properties of soft uncross-linked, cross-linked and rigid PVC were determined. Soft formulations were held in contact for 32 days with rigid PVC sheets. Plasticizer migration towards the interface causes an increase of dynamic friction compared to that of the reference rigid PVC.

  17. Highly conductive PEDOT:PSS on flexible substrate as ITO-free anode for polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Del Mauro, A. De Girolamo; Ricciardi, R.; Montanino, M.; Morvillo, P.; Minarini, C. [Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Portici Research Centre, p.le E. Fermi 1, 80055 Portici (Italy)

    2014-05-15

    In this work, highly conductive anode based on PEDOT:PSS is proposed as substitute of Indio-Tin Oxide (ITO) in flexible solar cells. The anodic conductive polymer was spin coated on a 125 μm thick polyethylene naphthalate (PEN) substrate. The obtained film was characterized in terms of structure and physical- chemical proprieties. The obtained results are very promising and the conductive film will be investigated in future as electrode in a complete polymeric solar cell.

  18. InP-Based Heterostructure Design and Growth for Semiconductor Nanomembrane Optoelectronics on Si and on Flexible Substrates

    Science.gov (United States)

    2014-05-21

    AFRL-AFOSR-UK-TR-2014-0015 InP-based heterostructure design and growth for semiconductor nanomembrane optoelectronics on Si and...TITLE AND SUBTITLE InP-based heterostructure design and growth for semiconductor nanomembrane optoelectronics on Si and on flexible substrates...on the realization of ultracompact microcavity lasers directly integrated on silicon. Using a stamp-assisted transfer-printing technology, silicon

  19. Flexible biochips for detection of biomolecules

    NARCIS (Netherlands)

    Peter, M.; Schüler, T.; Furthner, F.; Rensing, P.A.; Heck, G.T. van; Schoo, H.F.M.; Möllier, R.; Fritzsche, W.; Breemen, A.J.J.M. van; Meinders, E.R.

    2009-01-01

    Miniaturization of biosensors is envisaged by the development of biochips consisting of parallel microarray patterns of binding sites on rigid substrates, such as glass or silicon. Thin plastic substrates are promising flexible alternatives because of the possibility for large-area roll-to-roll manu

  20. Flexible biochips for detection of biomolecules

    NARCIS (Netherlands)

    Peter, M.; Schüler, T.; Furthner, F.; Rensing, P.A.; Heck, G.T. van; Schoo, H.F.M.; Möllier, R.; Fritzsche, W.; Breemen, A.J.J.M. van; Meinders, E.R.

    2009-01-01

    Miniaturization of biosensors is envisaged by the development of biochips consisting of parallel microarray patterns of binding sites on rigid substrates, such as glass or silicon. Thin plastic substrates are promising flexible alternatives because of the possibility for large-area roll-to-roll manu

  1. Flexible biochips for detection of biomolecules

    NARCIS (Netherlands)

    Peter, M.; Schüler, T.; Furthner, F.; Rensing, P.A.; Heck, G.T. van; Schoo, H.F.M.; Möllier, R.; Fritzsche, W.; Breemen, A.J.J.M. van; Meinders, E.R.

    2009-01-01

    Miniaturization of biosensors is envisaged by the development of biochips consisting of parallel microarray patterns of binding sites on rigid substrates, such as glass or silicon. Thin plastic substrates are promising flexible alternatives because of the possibility for large-area roll-to-roll

  2. Patterned growth of ZnO nanowires on flexible substrates for enhanced performance of flexible piezoelectric nanogenerators

    Science.gov (United States)

    Yang, Dechao; Qiu, Yu; Jiang, Qingyu; Guo, Zhaoshuai; Song, Wenbin; Xu, Jin; Zong, Yang; Feng, Qiuxia; Sun, Xiaoling

    2017-02-01

    Flexible piezoelectric nanogenerators (NGs) based on patterned growth of ZnO nanowires (PNWs) by the hydrothermal method are proposed for high-efficiency energy harvesting applications. The use of the PNWs in ZnO-based FPNGs results in a significant improvement in terms of the magnitude of the output currents of up to 6 times when compared with pristine ZnO NW-based FPNGs without patterned growth mode. The maximum output current was measured to be about 150 nA, which was enough to drive some micro/nanoelectronic devices. The improved output performance is mainly attributed to the patterned growth mode in FPNGs, which may significantly reduce the piezoelectric potential screening effect caused by free electrons in ZnO. This strategy may provide a highly promising platform as energy harvesting devices for viable industrial applications in portable/wearable nanodevices.

  3. Toward Plastic Smart Windows: Optimization of Indium Tin Oxide Electrodes for the Synthesis of Electrochromic Devices on Polycarbonate Substrates.

    Science.gov (United States)

    Laurenti, Marco; Bianco, Stefano; Castellino, Micaela; Garino, Nadia; Virga, Alessandro; Pirri, Candido F; Mandracci, Pietro

    2016-03-01

    Plastic smart windows are becoming one of the key elements in view of the fabrication of inexpensive, lightweight electrochromic (EC) devices to be integrated in the new generation of high-energy-efficiency buildings and automotive applications. However, fabricating electrochromic devices on polymer substrates requires a reduction of process temperature, so in this work we focus on the development of a completely room-temperature deposition process aimed at the preparation of ITO-coated polycarbonate (PC) structures acting as transparent and conductive plastic supports. Without providing any substrate heating or surface activation pretreatments of the polymer, different deposition conditions are used for growing indium tin oxide (ITO) thin films by the radiofrequency magnetron sputtering technique. According to the characterization results, the set of optimal deposition parameters is selected to deposit ITO electrodes having high optical transmittance in the visible range (∼90%) together with low sheet resistance (∼8 ohm/sq). The as-prepared ITO/PC structures are then successfully tested as conductive supports for the fabrication of plastic smart windows. To this purpose, tungsten trioxide thin films are deposited by the reactive sputtering technique on the ITO/PC structures, and the resulting single electrode EC devices are characterized by chronoamperometric experiments and cyclic voltammetry. The fast switching response between colored and bleached states, together with the stability and reversibility of their electrochromic behavior after several cycling tests, are considered to be representative of the high quality of the EC film but especially of the ITO electrode. Indeed, even if no adhesion promoters, additional surface activation pretreatments, or substrate heating were used to promote the mechanical adhesion among the electrode and the PC surface, the observed EC response confirmed that the developed materials can be successfully employed for the

  4. Laser-direct process of Cu nano-ink to coat highly conductive and adhesive metallization patterns on plastic substrate

    Science.gov (United States)

    Min, Hyungsuk; Lee, Byoungyoon; Jeong, Sooncheol; Lee, Myeongkyu

    2016-05-01

    We here present a simple, low-cost laser-direct process to fabricate conductive Cu patterns on plastic substrate. A Cu nano-ink was synthesized using Cu formate as a precursor. The Cu ink spin-coated on a polyimide substrate was selectively sintered using a pulsed ultraviolet laser beam. The unexposed regions of the coated ink could be removed by rinsing the whole film in the dispersion agent of the synthesized ink, which revealed a conductive Cu pattern. This allowed sintering and patterning to be simultaneously accomplished, with a minimum line width of ~20 μm available. The fabricated pattern remained strongly adhesive to the substrate and exhibited only a slight increase in resistance even after 1000 bending cycles to a radius of curvature of 4.8 mm.

  5. Making environmental sensors on plastic foil

    Directory of Open Access Journals (Sweden)

    Danick Briand

    2011-09-01

    Full Text Available With the emergence of the printed electronics industry, the development of sensing technologies on non conventional substrates such as plastic foils is on-going. In this article, we review the work performed and the trends in the development of environmental sensors on plastic and flexible foils. Our main focus is on the integration of temperature, humidity, and gas sensors on plastic substrates targeting low-power operation for wireless applications. Some perspectives in this dynamic field are also provided showing the potential for the realization of several types of transducers on substrates of different natures and their combination with other components to realize smart systems.

  6. Upgrading of recycled plastics obtained from flexible packaging waste by adding nanosilicates

    Science.gov (United States)

    Garofalo, E.; Claro, M.; Scarfato, P.; Di Maio, L.; Incarnato, L.

    2015-12-01

    Currently, the growing consumption of polymer products creates large quantities of waste materials resulting in public concern in the environment and people life. The efficient treatment of polymer wastes is still a difficult challenge and the recycling process represents the best way to manage them. Recently, many researchers have tried to develop nanotechnology for polymer recycling. The products prepared through the addition of nanoparticles to post-used plastics could offer the combination of improved properties, low weight, easy of processing and low cost which is not easily and concurrently found by other methods of plastic recycling. In this study materials, obtained by the separation and mechanical recycling of post-consumer packaging films of small size (organic modifier, were melt compounded with the recycled materials in a twin-screw extruder. The morphological, thermal, rheological and mechanical properties of the prepared nanocomposites were extensively discussed.

  7. Low-Cost, Disposable, Flexible and Highly Reproducible Screen Printed SERS Substrates for the Detection of Various Chemicals

    Science.gov (United States)

    Wu, Wei; Liu, Li; Dai, Zhigao; Liu, Juhua; Yang, Shuanglei; Zhou, Li; Xiao, Xiangheng; Jiang, Changzhong; Roy, Vellaisamy A. L.

    2015-05-01

    Ideal SERS substrates for sensing applications should exhibit strong signal enhancement, generate a reproducible and uniform response, and should be able to fabricate in large-scale and low-cost. Herein, we demonstrate low-cost, highly sensitive, disposable and reproducible SERS substrates by means of screen printing Ag nanoparticles (NPs) on a plastic PET (Polyethylene terephthalate) substrates. While there are many complex methods for the fabrication of SERS substrates, screen printing is suitable for large-area fabrication and overcomes the uneven radial distribution. Using as-printed Ag substrates as the SERS platform, detection of various commonly known chemicals have been done. The SERS detection limit of Rhodamine 6G (R6G) is higher than the concentration of 1 × 10-10 M. The relative standard deviation (RSD) value for 784 points on the detection of R6G and Malachite green (MG) is less than 20% revealing a homogeneous SERS distribution and high reproducibility. Moreover, melamine (MA) is detected in fresh liquid-milk without additional pretreatment, which may accelerate the application of rapid on-line detection of MA in liquid milk. Our screen printing method highlights the use of large-scale printing strategies for the fabrication of well-defined functional nanostructures with applications well beyond the field of SERS sensing.

  8. ZnO HEMTs on Flexible Substrates for Large Area Monolithic Antenna Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — AMBP Tech will implement Zinc Oxide high mobility material technology it has developed specifically for flexible electronics into a direct write process onto large...

  9. Empirical models for end-use properties prediction of LDPE: application in the flexible plastic packaging industry

    Directory of Open Access Journals (Sweden)

    Maria Carolina Burgos Costa

    2008-03-01

    Full Text Available The objective of this work is to develop empirical models to predict end use properties of low density polyethylene (LDPE resins as functions of two intrinsic properties easily measured in the polymers industry. The most important properties for application in the flexible plastic packaging industry were evaluated experimentally for seven commercial polymer grades. Statistical correlation analysis was performed for all variables and used as the basis for proper choice of inputs to each model output. Intrinsic properties selected for resin characterization are fluidity index (FI, which is essentially an indirect measurement of viscosity and weight average molecular weight (MW, and density. In general, models developed are able to reproduce and predict experimental data within experimental accuracy and show that a significant number of end use properties improve as the MW and density increase. Optical properties are mainly determined by the polymer morphology.

  10. Rolling-based direct-transfer printing: A process for large-area transfer of micro- and nanostructures onto flexible substrates

    Science.gov (United States)

    Grierson, D. S.; Flack, F. S.; Lagally, M. G.; Turner, K. T.

    2016-09-01

    A rolling-based printing approach for transferring arrays of patterned micro- and nano-structures directly from rigid fabrication substrates onto flexible substrates is presented. Transfer-printing experiments show that the new process can achieve high-yield and high-fidelity transfer of silicon nanomembrane components with diverse architectures to polyethylene terephthalate substrates over chip-scale areas (>1 × 1 cm2) in process are investigated through finite element simulations of the contact and transfer process. These mechanics models provide guidance for controlling the contact area and strain in the flexible substrate during transfer, both of which are key for achieving reproducible and controlled component transfer over large areas.

  11. Evaluation of transverse piezoelectric coefficient of ZnO thin films deposited on different flexible substrates: a comparative study on the vibration sensing performance.

    Science.gov (United States)

    Joshi, Sudeep; Nayak, Manjunatha M; Rajanna, K

    2014-05-28

    We report on the systematic comparative study of highly c-axis oriented and crystalline piezoelectric ZnO thin films deposited on four different flexible substrates for vibration sensing application. The flexible substrates employed for present experimental study were namely a metal alloy (Phynox), metal (aluminum), polyimide (Kapton), and polyester (Mylar). ZnO thin films were deposited by an RF reactive magnetron sputtering technique. ZnO thin films of similar thicknesses of 700 ± 30 nm were deposited on four different flexible substrates to have proper comparative studies. The crystallinity, surface morphology, chemical composition, and roughness of ZnO thin films were evaluated by respective material characterization techniques. The transverse piezoelectric coefficient (d31) value for assessing the piezoelectric property of ZnO thin films on different flexible substrates was measured by a four-point bending method. ZnO thin films deposited on Phynox alloy substrate showed relatively better material characterization results and a higher piezoelectric d31 coefficient value as compared to ZnO films on metal and polymer substrates. In order to experimentally verify the above observations, vibration sensing studies were performed. As expected, the ZnO thin film deposited on Phynox alloy substrate showed better vibration sensing performance. It has generated the highest peak to peak output voltage amplitude of 256 mV as compared to that of aluminum (224 mV), Kapton (144 mV), and Mylar (46 mV). Therefore, metal alloy flexible substrate proves to be a more suitable, advantageous, and versatile choice for integrating ZnO thin films as compared to metal and polymer flexible substrates for vibration sensing applications. The present experimental study is extremely important and helpful for the selection of a suitable flexible substrate for various applications in the field of sensor and actuator technology.

  12. Direct and Efficient Preparation of Graphene Transparent Conductive Films on Flexible Poly Carbonate Substrate by Spray-Coating.

    Science.gov (United States)

    Li, Xiuqiang; Zhang, Dong; Yang, Chao; Shang, Yu

    2015-12-01

    Owing to the hydrophobic property and heat-labile of flexible substances, it is difficult to prepare graphene transparent conductive films (TCFs) on flexible substrate in a direct and effective way. Here we prepared a good dispersion of water/graphene oxide (GO)/ethanol, and the fabrication of graphene TCFs on flexible poly carbonate (PC) substrate was made by spray deposition of water/GO/ethanol, followed by the reduction of hydriodic acid (HI) fuming method. It can be found that when ethanol was added to GO solution, the drying dynamics of the spraying solvent increased and the problem of wetting property of GO dispersion on the PC could be effectively resolved. HI acid vapour can achieve an effective reduction of the GO film. The reduction effect of HI acid fuming method is more effective in comparation with traditional HI acid immersed method. An increase in spraying concentration can lead to a rise in coverage degree of film and folding degree of surface. 1/500 mg/ml is a relatively appropriate concentration for spray-coating. The thickness of the film was controlled by adjusting the spraying volume of water/GO/ethanol dispersion. The graphene TCFs exhibit a sheet resistance of less than 15.3 kΩ/sq at 74% transmittance.

  13. Substrate temperature optimization for Cu(In, Ga)Se{sub 2} solar cells on flexible stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Liang, X.; Zhu, H.; Chen, J., E-mail: chenjingwei@126.com; Zhou, D.; Zhang, C.; Guo, Y.; Niu, X.; Li, Z.; Mai, Y., E-mail: yaohuamai@hbu.edu.cn

    2016-04-15

    Graphical abstract: - Highlights: • CIGS thin films are deposited on flexible SS substrates at different substrate temperatures. • CIGS thin films deposited at different T{sub S2} show different Ga/(Ga + In) ratio profiles. • All CIGS thin films show (112) and (220/204) preferred orientations with a shift to higher angles. • Conversion efficiency of 11.3% is obtained for CIGS solar cells deposited at 500 °C. - Abstract: Cu(In, Ga)Se{sub 2} (CIGS) thin films are deposited on flexible stainless steel (SS) substrates using the so called 3-stage co-evaporation process at different substrate temperatures ranging from 440 °C to 640 °C during the 2nd stage and the 3rd stage (T{sub S2}). The effects of T{sub S2} on the properties of CIGS thin films are systematically investigated. It is found by secondary ion mass spectrometry measurement that CIGS thin films deposited at different T{sub S2} show different Ga/(Ga + In) ratio (GGI) profiles along the growth direction. High T{sub S2} facilitates the grain growth and leads to larger grain size. However, high T{sub S2} worsens the spectral response of CIGS solar cells in the long wavelength range, which is partly attributed to the too much iron atom diffusion from the SS substrates into the CIGS thin films. All CIGS thin films show (112) preferred orientations with a shift to higher angle due to variation of compositions. A shoulder-like two-peak structure of (112) and (220/204) peaks appears for CIGS thin films deposited at lower T{sub S2}. Conversion efficiency of 11.3% is obtained for CIGS thin film solar cells deposited at the T{sub S2} of 500 °C.

  14. The neural substrates of cognitive flexibility are related to individual differences in preschool irritability: A fNIRS investigation

    Directory of Open Access Journals (Sweden)

    Yanwei Li

    2017-06-01

    Full Text Available Preschool (age 3–5 is a phase of rapid development in both cognition and emotion, making this a period in which the neurodevelopment of each domain is particularly sensitive to that of the other. During this period, children rapidly learn how to flexibly shift their attention between competing demands and, at the same time, acquire critical emotion regulation skills to respond to negative affective challenges. The integration of cognitive flexibility and individual differences in irritability may be an important developmental process of early childhood maturation. However, at present it is unclear if they share common neural substrates in early childhood. Our main goal was to examine the neural correlates of cognitive flexibility in preschool children and test for associations with irritability. Forty-six preschool aged children completed a novel, child-appropriate, Stroop task while dorsolateral prefrontal cortex (DLPFC activation was recorded using functional Near Infrared Spectroscopy (fNIRS. Parents rated their child’s irritability. Results indicated that left DLPFC activation was associated with cognitive flexibility and positively correlated with irritability. Right DLPFC activation was also positively correlated with irritability. Results suggest the entwined nature of cognitive and emotional neurodevelopment during a developmental period of rapid and mutual acceleration.

  15. Plastic pikas: Behavioural flexibility in low-elevation pikas (Ochotona princeps)

    Science.gov (United States)

    Varner, Johanna; Horns, Joshua J.; Lambert, Mallory S.; Westberg, Elizabeth; Ruff, James; Wolfenberger, Katelyn; Beever, Erik; Dearing, M. Denise

    2016-01-01

    Behaviour is an important mechanism for accommodating rapid environmental changes. Understanding a species’ capacity for behavioural plasticity is therefore a key, but understudied, aspect of developing tractable conservation and management plans under climate-change scenarios. Here, we quantified behavioural differences between American pikas (Ochotona princeps) living in an atypical, low-elevation habitat versus those living in a more-typical, alpine habitat. With respect to foraging strategy, low-elevation pikas spent more time consuming vegetation and less time caching food for winter, compared to high-elevation pikas. Low-elevation pikas were also far more likely to be detected in forested microhabitats off the talus than their high-elevation counterparts at midday. Finally, pikas living in the atypical habitat had smaller home range sizes compared to those in typical habitat or any previously published home ranges for this species. Our findings indicate that behavioural plasticity likely allows pikas to accommodate atypical conditions in this low-elevation habitat, and that they may rely on critical habitat factors such as suitable microclimate refugia to behaviourally thermoregulate. Together, these results suggest that behavioural adjustments are one important mechanism by which pikas can persist outside of their previously appreciated dietary and thermal niches.

  16. Room-temperature bonding method for polymer substrate of flexible electronics by surface activation using nano-adhesion layers

    Science.gov (United States)

    Matsumae, Takashi; Fujino, Masahisa; Suga, Tadatomo

    2015-10-01

    A sealing method for polymer substrates to be used in flexible electronics is studied. For this application, a low-temperature sealing method that achieves flexible bonding of inorganic bonding material is required, but no conventional technique satisfies these requirements simultaneously. In this study, a new polymer bonding method using thin Si and Fe layers and the surface activated bonding (SAB) method are applied to bond poly(ethylene naphthalate) (PEN) films to each other. PEN films can be bonded via the proposed method without voids at room temperature, and the bonded samples are bendable. The adhesion strength of the bonded samples is so strong that fracture occurs in the polymer bulk rather than at the bond interface. Investigations of the bonded samples by transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR) reveal that bonding is achieved by chemical interactions between the polymer surface and deposited atoms.

  17. Full densification of inkjet-printed copper conductive tracks on a flexible substrate utilizing a hydrogen plasma sintering

    Science.gov (United States)

    Kwon, Young-Tae; Lee, Young-In; Kim, Seil; Lee, Kun-Jae; Choa, Yong-Ho

    2017-02-01

    Low temperature sintering techniques are crucial in developing flexible printed electronics. In this work, we demonstrate a novel hydrogen plasma sintering method that achieves a full reduction and densification of inkjet-printed patterns using a copper complex ion ink. After inkjet printing on polyethylene terephthalate (PET) substrates, both hydrogen plasma and conventional hydrogen thermal treatment were employed to compare the resulting microstructures, electrical properties and anti-oxidation behavior. The plasma treated pattern shows a fully densified microstructure with a resistivity of 3.23 μΩ cm, while the thermally treated pattern shows a relatively poor microstructure and high resistivity. In addition, the hydrogen plasma-treated copper pattern retains its electrical resistivity for one month without any significant decrease. This novel hydrogen plasma sintering technique could be used to produce conductive patterns with excellent electrical properties, allowing for highly reliable flexible printed electronics.

  18. Self-powered p-NiO/n-ZnO heterojunction ultraviolet photodetectors fabricated on plastic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Md Rezaul [Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Department of Electrical and Computer Engineering, George Mason University, 4400 University Drive, Fairfax, Virginia 22030 (United States); Xie, Ting; Liu, Guannan [Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742 (United States); Barron, Sara C. [Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Nguyen, Nhan V. [Semiconductor and Dimensional Metrology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Motayed, Abhishek [Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Rao, Mulpuri V. [Department of Electrical and Computer Engineering, George Mason University, 4400 University Drive, Fairfax, Virginia 22030 (United States); Debnath, Ratan, E-mail: ratan.debnath@nist.gov [Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    2015-10-01

    A self-powered ultraviolet (UV) photodetector (PD) based on p-NiO and n-ZnO was fabricated using low-temperature sputtering technique on indium doped tin oxide (ITO) coated plastic polyethylene terephthalate (PET) substrates. The p-n heterojunction showed very fast temporal photoresponse with excellent quantum efficiency of over 63% under UV illumination at an applied reverse bias of 1.2 V. The engineered ultrathin Ti/Au top metal contacts and UV transparent PET/ITO substrates allowed the PDs to be illuminated through either frontside or backside. Morphology, structural, chemical, and optical properties of sputtered NiO and ZnO films were also investigated.

  19. Self-powered p-NiO/n-ZnO heterojunction ultraviolet photodetectors fabricated on plastic substrates

    Directory of Open Access Journals (Sweden)

    Md Rezaul Hasan

    2015-10-01

    Full Text Available A self-powered ultraviolet (UV photodetector (PD based on p-NiO and n-ZnO was fabricated using low-temperature sputtering technique on indium doped tin oxide (ITO coated plastic polyethylene terephthalate (PET substrates. The p-n heterojunction showed very fast temporal photoresponse with excellent quantum efficiency of over 63% under UV illumination at an applied reverse bias of 1.2 V. The engineered ultrathin Ti/Au top metal contacts and UV transparent PET/ITO substrates allowed the PDs to be illuminated through either frontside or backside. Morphology, structural, chemical, and optical properties of sputtered NiO and ZnO films were also investigated.

  20. Metal-assisted exfoliation (MAE): green, roll-to-roll compatible method for transferring graphene to flexible substrates

    Science.gov (United States)

    Zaretski, Aliaksandr V.; Moetazedi, Herad; Kong, Casey; Sawyer, Eric J.; Savagatrup, Suchol; Valle, Eduardo; O'Connor, Timothy F.; Printz, Adam D.; Lipomi, Darren J.

    2015-01-01

    Graphene is expected to play a significant role in future technologies that span a range from consumer electronics, to devices for the conversion and storage of energy, to conformable biomedical devices for healthcare. To realize these applications, however, a low-cost method of synthesizing large areas of high-quality graphene is required. Currently, the only method to generate large-area single-layer graphene that is compatible with roll-to-roll manufacturing destroys approximately 300 kg of copper foil (thickness = 25 μm) for every 1 g of graphene produced. This paper describes a new environmentally benign and scalable process of transferring graphene to flexible substrates. The process is based on the preferential adhesion of certain thin metallic films to graphene; separation of the graphene from the catalytic copper foil is followed by lamination to a flexible target substrate in a process that is compatible with roll-to-roll manufacturing. The copper substrate is indefinitely reusable and the method is substantially greener than the current process that uses relatively large amounts of corrosive etchants to remove the copper. The sheet resistance of the graphene produced by this new process is unoptimized but should be comparable in principle to that produced by the standard method, given the defects observable by Raman spectroscopy and the presence of process-induced cracks. With further improvements, this green, inexpensive synthesis of single-layer graphene could enable applications in flexible, stretchable, and disposable electronics, low-profile and lightweight barrier materials, and in large-area displays and photovoltaic modules.

  1. Enhanced Fracture Resistance of Flexible ZnO:Al Thin Films in Situ Sputtered on Bent Polymer Substrates.

    Science.gov (United States)

    Choi, Hong Rak; Eswaran, Senthil Kumar; Lee, Seung Min; Cho, Yong Soo

    2015-08-19

    Improving the fracture resistance of inorganic thin films is one of the key challenges in flexible electronic devices. A nonconventional in situ sputtering method is introduced to induce residual compressive stress in ZnO:Al thin films during deposition on a bent polymer substrate. The films grown under a larger prebending strain resulted in a higher fracture resistance to applied strains by exhibiting a ∼ 70% improvement in crack-initiating critical strain compared with the reference sample grown without bending. This significant improvement is attributed to the induced residual stress, which helps to prevent the formation of cracks by counteracting the applied strain.

  2. Post annealing effects on the properties of sputtered nano-crystallite indium tin oxide thin films on flexible polyimide substrate

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi Gheidari, A.; Iraj, M.; Kazemzad, M.; Behafarid, F. [Materials and Energy Research Center (MERC), Tehran (Iran); Hadad Dabaghi, H. [Departmet of Chemistry, Islamic Azad University of Karaj, Karaj (Iran); Kalhor, D. [Department of Physics, Damghan University of Basic Sciences (Iran)

    2008-07-01

    Indium tin oxide (ITO) thin films were deposited onto flexible polyimide substrates using RF sputtering system at room temperature. The deposited films were then heat treated at different temperatures in air and vacuum atmospheres. The structural variations and as consequence the electro-optical characteristic variations of the films were systematically investigated as a function of post annealing temperature and atmosphere. The structure of the films was studied by means of XRD and SEM techniques and the electro-optical characteristics were measured by four point probe and spectrophotometer, respectively. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Theoretical Investigation of Influence of Mechanical Stress on Magnetic Properties of Ferromagnetic/Antiferromagnetic Bilayers Deposited on Flexible Substrates

    Institute of Scientific and Technical Information of China (English)

    Yu-Hao Bai; Xia Wang; Lin-Ping Mu; Xiao-Hong Xu

    2016-01-01

    Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated.The hysteresis loops with different magnitudes and orientations of the stress can be classified into three types.The corresponding physical conditions for each type of the loop are deduced based on the principle of minimal energy.The equation of the critical stress is derived,which can judge whether the loops show hysteresis or not.Numerical calculations suggest that except for the magnitude of the mechanical stress,the relative orientation of the stress is also an important factor to tune the exchange bias effect.

  4. The Structural and Electrical Properties of Nanostructures ZnO Thin Films on Flexible Substrate

    Directory of Open Access Journals (Sweden)

    Nur Sa’adah Muhamad Sauki

    2017-06-01

    Full Text Available Zinc oxide (ZnO thin films were deposited on Teflon substrates by radio frequency (RF magnetron sputtering method at different substrate temperature. The dependence of residual stress on the substrate temperature was investigated in this work due to the growth process, the bombardment of energetic particles and process heating to the deposited thin films. From field emission scanning electron microscope (FESEM images, samples that deposited at various substrate temperatures consists nano-sized particles. The obtained X-ray diffraction (XRD results, it suggested that ZnO thin film deposited at 40oC with highly c-axis oriented shows unstressed film compared to other thin films. Besides that, the ZnO thin films deposited at 40oC shows improved electrical properties.

  5. Light Trapping in Thin Film Silicon Solar Cells on Plastic Substrates

    NARCIS (Netherlands)

    de Jong, M.M.

    2013-01-01

    In the search for sustainable energy sources, solar energy can fulfil a large part of the growing demand. The biggest threshold for large-scale solar energy harvesting is the solar panel price. For drastic cost reductions, roll-to-roll fabrication of thin film silicon solar cells using plastic subst

  6. Light Trapping in Thin Film Silicon Solar Cells on Plastic Substrates

    NARCIS (Netherlands)

    de Jong, M.M.

    2013-01-01

    In the search for sustainable energy sources, solar energy can fulfil a large part of the growing demand. The biggest threshold for large-scale solar energy harvesting is the solar panel price. For drastic cost reductions, roll-to-roll fabrication of thin film silicon solar cells using plastic

  7. Light Trapping in Thin Film Silicon Solar Cells on Plastic Substrates

    NARCIS (Netherlands)

    de Jong, M.M.|info:eu-repo/dai/nl/325844208

    2013-01-01

    In the search for sustainable energy sources, solar energy can fulfil a large part of the growing demand. The biggest threshold for large-scale solar energy harvesting is the solar panel price. For drastic cost reductions, roll-to-roll fabrication of thin film silicon solar cells using plastic subst

  8. Effects of Annealing Temperature on Properties of Ti-Ga–Doped ZnO Films Deposited on Flexible Substrates

    Science.gov (United States)

    Chen, Tao-Hsing; Chen, Ting-You

    2015-01-01

    An investigation is performed into the optical, electrical, and microstructural properties of Ti-Ga–doped ZnO films deposited on polyimide (PI) flexible substrates and then annealed at temperatures of 300 °C, 400 °C, and 450 °C, respectively. The X-ray diffraction (XRD) analysis results show that all of the films have a strong (002) Ga doped ZnO (GZO) preferential orientation. As the annealing temperature is increased to 400 °C, the optical transmittance increases and the electrical resistivity decreases. However, as the temperature is further increased to 450 °C, the transmittance reduces and the resistivity increases due to a carbonization of the PI substrate. Finally, the crystallinity of the ZnO film improves with an increasing annealing temperature only up to 400 °C and is accompanied by a smaller crystallite size and a lower surface roughness.

  9. Bending stability of GaN grown on a metallic flexible substrate by plasma-assisted molecular beam epitaxy

    Science.gov (United States)

    Rodríguez, A. G.; Chávez-Veloz, S. G.; Compeán-García, V. D.; López-Luna, E.; Vidal, M. A.

    2017-08-01

    GaN thin films were grown on flexible metallic substrates by molecular beam epitaxy. MgO buffer layers were deposited by spin coating on Ni-Mo-Cr (Hastelloy C-276) alloy tapes that were used as substrates. The structural characterization of the GaN/MgO/hastelloy samples was performed by x-ray diffraction and Raman spectroscopy. The obtained nanometric films have the stable hexagonal phase (α-GaN) with an average crystallite size of 18 nm. The long and short range order of GaN decrease when the structure is bent. The most significant variations in the structural properties occur between 100 and 250 bending cycles.

  10. An experimental investigation of piezoelectric P(VDF-TrFE) thick film on flexible substrate as energy harvester

    Science.gov (United States)

    Khoon Keat, Chow; Swee Leong, Kok; Kok Tee, Lau

    2017-06-01

    This paper proposes an experimental inves tigation of energy harvester using poly(vinylidene fluoride-trifluoroethylene) or P(VDF-TrFE) thick-film on flexible substrate by using print screen and rod method. Polyester film being used as the substrate where a sandwiched layer of electrode-piezopolymer-electrode thick film is deposited on. The thick-film is then annealed at 100°C and polarized at 100 V for the film with a thickness of about 18µm, being inspected under EDX, FESEM and XRD. The fabricated energy harvester piezoelectric is able to generate a maximum output power of 4.36 µW at an externa l electrical load of 1 kΩ with a maximum peak-to-peak of about 3.0V when an impact free-fall force of 0.2N was applied on the thick-film.

  11. Flexible Displays Made with Plastic Electronics%采用塑料电子技术制造的柔性显示器

    Institute of Scientific and Technical Information of China (English)

    Seamus Burns; 杨明; 熊绍珍

    2011-01-01

    Plastic Logic has designed and constructed a full-scale manufacturing facility for flexible display modules fabricated using organic semiconductors("plastic electronics").These display modules are lightweight,flexible,and robust and are used in the QUEpro%Plastic Logic公司设计并建造了一个采用有机半导体制造柔性显示组件("塑料电子学")的全尺寸制造工厂。这些显示组件具有重量轻、可弯曲、坚固的优点,并用于QUEproReader产品上——这是于2010年1月推出的一款专为商务人士打造的便携电子阅读器。

  12. Ammonia plasma modification towards a rapid and low temperature approach for tuning electrical conductivity of ZnO nanowires on flexible substrates

    Science.gov (United States)

    Ong, Wei Li; Zhang, Chun; Ho, Ghim Wei

    2011-10-01

    Though the fabrication of ZnO nanostructures is economical and low temperature, the lack of a facile, reliable and low temperature methodology to tune its electrical conductivity has prevented it from competing with other semiconductors. Here, we carried out surface modification of ZnO nanowires using ammonia plasma with no heat treatment, and studied their electrical properties over an extended time frame of more than a year. The fabrication of flexible devices was demonstrated via various methods of transferring and aligning as-synthesized ZnO nanowires onto plastic substrates. Hall measurements of the plasma modified ZnO nanowires revealed p-type conductivity. The N1s peak was present in the X-ray photoelectron spectrum of the surface modified ZnO, showing the presence of ammonia complexes. Low temperature photoluminescence showed evidence of acceptor-bound exciton emission. The resulting electrical devices, a chemical sensor and p-n homojunction, show the tunable electrical response of the surface modified ZnO nanowires.

  13. Deformation behavior of Re alloyed Mo thin films on flexible substrates: In situ fragmentation analysis supported by first-principles calculations.

    Science.gov (United States)

    Jörg, Tanja; Music, Denis; Hauser, Filipe; Cordill, Megan J; Franz, Robert; Köstenbauer, Harald; Winkler, Jörg; Schneider, Jochen M; Mitterer, Christian

    2017-08-07

    A major obstacle in the utilization of Mo thin films in flexible electronics is their brittle fracture behavior. Within this study, alloying with Re is explored as a potential strategy to improve the resistance to fracture. The sputter-deposited Mo1-xRex films (with 0 ≤ x ≤ 0.31) were characterized in terms of structural and mechanical properties, residual stresses as well as electrical resistivity. Their deformation behavior was assessed by straining 50 nm thin films on polyimide substrates in uniaxial tension, while monitoring crack initiation and propagation in situ by optical microscopy and electrical resistance measurements. A significant toughness enhancement occurs with increasing Re content for all body-centered cubic solid solution films (x ≤ 0.23). However, at higher Re concentrations (x > 0.23) the positive effect of Re is inhibited due to the formation of dual-phase films with the additional close packed A15 Mo3Re phase. The mechanisms responsible for the observed toughness behavior are discussed based on experimental observations and electronic structure calculations. Re gives rise to both increased plasticity and bond strengthening in these Mo-Re solid solutions.

  14. Density- and adhesion-controlled ZnO nanorod arrays on the ITO flexible substrates and their electrochromic performance

    Energy Technology Data Exchange (ETDEWEB)

    Hu Anzheng, E-mail: sporthaz@126.co [Institute of Nanoscience and Nanotechnology, Central China Normal University, Wuhan 430079 (China) and School of Physics and Electronic Engineering, Xiangfan University, Xiangfan 441053, Hubei (China); Wu Fei; Liu Jinping; Jiang Jian; Ding Ruimin; Li Xin; Cheng Cuixia; Zhu Zhihong [Institute of Nanoscience and Nanotechnology, Central China Normal University, Wuhan 430079 (China); Huang Xintang, E-mail: xthuang@phy.ccnu.edu.c [Institute of Nanoscience and Nanotechnology, Central China Normal University, Wuhan 430079 (China)

    2010-09-24

    Research highlights: {yields} We embarked on for the first time a study that the large-scale ZnO nanorod arrays (NRs) were grown directly on flexible ITO/PET substrates. {yields} The density can be readily controlled by adjusting the thickness of pre-preparated ZnO seed layers. And the occupied space ratio (OSR) can be controlled by the density and relevant kinetics conditions of ZnO NRs growth. {yields} The experimental effect indicates that the ZnO NRs using sputtering-prepared seed layers show superior adhesion property to substrate and stability when compared with the spin-coated method. {yields} The ZnO NRs with optimum density and OSR (diameter, {approx}140 nm; density, {approx}3.34 x 109 rods cm{sup -2}; and OSR, {approx}52%) can be obtained by using the solution containing 0.05 M Zn(NO{sub 3}){sub 2}.6H{sub 2}O and 0.06 M C{sub 6}H{sub 12}N{sub 4} at 75 {sup o}C for 24 h, before about 4-5 nm thickness of ZnO seed layers were sputtered. {yields} It has been found that the ZnO NRs with optimum density and OSR (density, {approx}3.34 x 10{sup 9} rods cm{sup -2}; diameter, {approx} 140 nm; and OSR, {approx}52%) demonstrate optimal absorption capability to viologen molecules and excellent electrochromic performance. {yields} Our results would provide a promising route to study flexible electrochromic and further find the optimized electrode structure. - Abstract: We report large-scale density- and adhesion-controlled ZnO nanorod arrays (NRs) directly grown on flexible ITO/PET substrates and have studied their absorption capability to viologen molecules and electrochromic performance. The density can be readily controlled by adjusting the thickness of pre-preparated ZnO seed layers. And the adhesion property of the ZnO NRs to substrates can be controlled by different methods of pre-preparation ZnO seed layer. The effect indicates that the ZnO NRs using sputtering-prepared seed layers show superior adhesion property to substrate and resistance capacity to

  15. Preparation and characterization of ZnTe as an interlayer for CdS/CdTe substrate thin film solar cells on flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xianjin, E-mail: xianjinfeng@gmail.com; Singh, Kartikay; Bhavanam, Sushma; Palekis, Vasilios; Morel, Don L.; Ferekides, Chris

    2013-05-01

    ZnTe thin films have been prepared on Mo-coated stainless steel substrates by the close spaced sublimation (CSS) technique. Cu-doped ZnTe (ZnTe:Cu) films are prepared by immersing the as-deposited samples in a CuCl–H{sub 2}O solution. The structural and morphological properties of the ZnTe films as a function of substrate temperature are investigated using X-ray diffraction and scanning electron microscopy. CdS/CdTe solar cells with and without the ZnTe and ZnTe:Cu interlayers are prepared and characterized with current–voltage (J–V), spectral response, and capacitance–voltage measurements. The structural and morphological properties of the ZnTe films prepared by CSS are found to be strongly influenced by the substrate temperature. The ‘roll-over’ behavior in the J–V characteristics of the CdS/CdTe solar cells due to a Schottky barrier at the back contact can be eliminated using ZnTe as the interlayer. Preliminary results on the application of ZnTe:Cu films suggest that the open circuit voltage and fill factor can be further improved, depending on processing conditions. - Highlights: ► Thin film CdTe solar cells on flexible stainless steel substrates are prepared. ► Using ZnTe can eliminate the ‘roll-over’ behavior in the current–voltage curve. ► Incorporating Cu can further improve the open circuit voltage and fill factor.

  16. Structural plasticity in the human cytosolic sulfotransferase dimer and its role in substrate selectivity and catalysis.

    Science.gov (United States)

    Tibbs, Zachary E; Rohn-Glowacki, Katie Jo; Crittenden, Frank; Guidry, Amber L; Falany, Charles N

    2015-02-01

    The cytosolic sulfotransferases (SULTs) are dimeric enzymes that help maintain homeostasis through the modulation of hormone and drug activity by catalyzing their transformation into hydrophilic sulfate esters and increasing their excretion. Each of the thirteen active human SULT isoforms displays a unique substrate specificity pattern that underlies its individual role in our bodies. These specificities have proven to be complex, in some cases masking the biological role of specific isoforms. The first part of this review offers a short summary of historical underpinnings of human SULTs, primarily centered on the characterization of each isoform's kinetic and structural properties. Recent structural investigations have revealed each SULT has an active site "lid" that undergoes restructuring once the cofactor/sulfonate donor, 3'-phosphoadenosine-5'-phosphosulfate (PAPS), binds to the enzyme. This structural rearrangement can alter substrate-binding profiles, therefore complicating enzyme/substrate interactions and making substrate/cosubstrate concentrations and binding order important considerations in enzyme functionality. Molecular dynamic simulations have recently been employed to describe this restructuring in an attempt to offer insight to its effects on substrate selectivity. In addition to reviewing new data on SULT molecular dynamics, we will discuss the contribution of PAPS concentrations and SULT dimerization in the regulation of SULT activity within the human body.

  17. The electrodeposition of multilayers on a polymeric substrate in flexible organic photovoltaic solar cells

    Science.gov (United States)

    Guedes, Andre F. S.; Guedes, Vilmar P.; Souza, Monica L.; Tartari, Simone; Cunha, Idaulo J.

    2015-09-01

    Flexible organic photovoltaic solar cells have drawn intense attention due to their advantages over competing solar cell technologies. The method utilized to deposit as well as to integrate solutions and processed materials, manufacturing organic solar cells by the Electrodeposition System, has been presented in this research. In addition, we have demonstrated a successful integration of a process for manufacturing the flexible organic solar cell prototype and we have discussed on the factors that make this process possible. The maximum process temperature was 120°C, which corresponds to the baking of the active polymeric layer. Moreover, the new process of the Electrodeposition of complementary active layer is based on the application of voltage versus time in order to obtain a homogeneous layer with thin film. This thin film was not only obtained by the electrodeposition of PANI-X1 on P3HT/PCBM Blend, but also prepared in perchloric acid solution. Furthermore, these flexible organic photovoltaic solar cells presented power conversion efficiency of 12% and the inclusion of the PANI-X1 layer reduced the effects of degradation on these organic photovoltaic panels induced by solar irradiation. Thus, in the Scanning Electron Microscopy (SEM), these studies have revealed that the surface of PANI-X1 layers is strongly conditioned by the dielectric surface morphology.

  18. Two-beam laser fabrication technique and the application for fabricating conductive silver nanowire on flexible substrate

    Science.gov (United States)

    He, Gui-Cang; Zheng, Mei-Ling; Dong, Xian-Zi; Liu, Jie; Duan, Xuan-Ming; Zhao, Zhen-Sheng

    2017-03-01

    In this study, a two-beam laser fabrication technique is proposed to fabricate silver nanowire (AgNW) on the polyethylene terephthalate (PET) substrate. The femtosecond pulse laser in the technique plays a role in generating Ag nanoparticles from the silver aqueous solution by multiphoton photoreduction. The continuous wave (CW) laser of the technique works as optical tweezers, and make the Ag nanoparticles gather to a continuous AgNW by the optical trapping force. The optical trapping force of the CW laser was calculated under our experimental condition. The flexibility and the resistance stability of the AgNW that fabricated by this technique are very excellent. Compared to the resistance of the AgNW without bending, the decreasing rate of the AgNW resistance is about 16% under compressed bending condition at the radius of 1 mm, and the increasing rate of the AgNW resistance is only 1.3% after the AgNW bended about 3500 times at the bending radius of 1 mm. The study indicates that the AgNW is promising for achieving flexible device and would promote the development of the flexible electronics.

  19. Two-beam laser fabrication technique and the application for fabricating conductive silver nanowire on flexible substrate

    Directory of Open Access Journals (Sweden)

    Gui-Cang He

    2017-03-01

    Full Text Available In this study, a two-beam laser fabrication technique is proposed to fabricate silver nanowire (AgNW on the polyethylene terephthalate (PET substrate. The femtosecond pulse laser in the technique plays a role in generating Ag nanoparticles from the silver aqueous solution by multiphoton photoreduction. The continuous wave (CW laser of the technique works as optical tweezers, and make the Ag nanoparticles gather to a continuous AgNW by the optical trapping force. The optical trapping force of the CW laser was calculated under our experimental condition. The flexibility and the resistance stability of the AgNW that fabricated by this technique are very excellent. Compared to the resistance of the AgNW without bending, the decreasing rate of the AgNW resistance is about 16% under compressed bending condition at the radius of 1 mm, and the increasing rate of the AgNW resistance is only 1.3% after the AgNW bended about 3500 times at the bending radius of 1 mm. The study indicates that the AgNW is promising for achieving flexible device and would promote the development of the flexible electronics.

  20. Stress impedance effect of FeCoSiB/Cu/FeCoSiB sandwich layers on flexible substrate

    Energy Technology Data Exchange (ETDEWEB)

    Peng, B., E-mail: bpeng@uestc.edu.c [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zhang, W.L.; Liu, J.D.; Zhang, W.X. [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2011-06-15

    FeCoSiB/Cu/FeCoSiB sandwich layers were deposited on flexible substrate to develop flexible stress/strain sensors. The influence of stress on the impedance of the multilayers is reported. The results show that the variation of the impedance increases with the increase in deflection of the free end of the cantilever. A relative change in impedance of 6.4% is obtained in the FeCoSiB(1.5 {mu}m)/Cu(0.25 {mu}m)/FeCoSiB(1.5 {mu}m) sandwich layers at 1 MHz with deflection of 2 mm. The stress impedance effects are sensitive to the frequency of the current and the thickness of both FeCoSiB and Cu layers. The stress impedance effect increases with the increase in the thickness of FeCoSiB or Cu layers. The stress impedance effect increases slightly with the increase in frequency and decreases with the further increase in frequency, which can be understood by the stress and frequency-dependent permeability of magnetic films. - Research highlights: We deposited FeCoSiB/Cu/FeCoSiB multilayer on flexible substrate. We studied the stress impedance effect of FeCoSiB/Cu/FeCoSiB multilayer. Stress impedance effect increases with thickness of both FeCoSiB and Cu layer. Stress impedance effect is dependent on current frequency. Results are understood using stress and frequency-dependent permeability.

  1. Simulation of the fluid structure interaction for an aerostatic bearing and a flexible substrate

    NARCIS (Netherlands)

    Olieslagers, R.; Wild, M. de; Melick, S. van; Knaapen, R.

    2014-01-01

    The fluid structure interaction for an aerostatic bearing and a substrate is solved numerically by a semi-analytical model, programmed in the software package MATLAB. This semi-analytical model uses a fluidic network of resistances and capacities to solve the pressure field in the bearing channel. T

  2. Plasticity and Interfacial Dislocation Mechanisms in Epitaxial and Polycrystalline Al Films Constrained by Substrates

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Stresses in epitaxial and textured Al films were determined by substrate-curvature measurements. It was found that in both cases the flow stresses increase with decreasing film thickness. The flow stresses in the epitaxial Al films are in agreement with a dislocation-based model, while the same model strongly underestimates the flow stresses of textured Al films. In-situ transmission electron microscopy studies indicate that dislocations channeling through epitaxial Al films on single-crystalline (0001) α-AI2O3 substrates frequently deposit dislocation segments adjacent to the interface. Furthermore, the AI/α-AI2O3 interface acted as a dislocation source. In this case, the interface is between two crystalline lattices. In contrast, the interface of textured Al films on oxidized silicon substrates is between the crystalline Al and the amorphous SiOx interlayer. It is speculated that the different nature of the interfaces changes dislocation mechanisms and thus influences the flow stresses.

  3. Manufacture and Evaluation of Light Emitting Diode Package Substrate Using Flexible Printed Circuit Board.

    Science.gov (United States)

    Park, Jung-Kab; Shin, Jin-Ha; Jung, Mun-Gi; Shigehisa, Tomabechi; Park, Hwa-Sun; Suh, Su-Jeong

    2015-10-01

    Unlike other light sources such as fluorescent lamps and incandescent bulbs, light-emitting diodes (LED) convert 70-80% of energy into heat. If the heat produced an LED chip is not effectively released, its luminous efficiency and lifespan are reduced. Therefore, as a method effectively release heat, an LED PKG substrate containing a heat-releasing material with excellent thermal conductance was fabricated, and its thermal resistance and luminous efficiency were analyzed. In this experiment, a thin polyimide film with excellent ductility was used to fabricate the LED PKG substrate. A 35-μm-thick Cu foil with excellent thermal conductance was subjected to high temperature and pressure and attached to both sides of the polyimide film. By electroplating Ag or Au, which has excellent thermal conductance, for us as the electrode and heat-releasing material, LED PKG substrate was fabricated with a thickness of approximately 170 μm. (-40 °C --> RT --> 120 °C). The results revealed that the LED PKG substrate having a Ag electrode with excellent thermal conductance had an excellent thermal resistance of approximately 4.2 °C/W (Au electrode: 5.6 °C/W). The luminous flux after 100 cycles in the thermal shock test was reduced by approximately 0.09% (Au electrode: 2.77%), indicating that the LED PKG substrate had excellent thermal resistance without any mechanical and material defects in a rapid-temperature-changing environment. The advantages and excellent thermal resistance can be exploited in cellular phones and LCD panels, and heat-releasing problems in thin panels be solved.

  4. Mesenchymal stem cell adhesion but not plasticity is affected by high substrate stiffness

    Directory of Open Access Journals (Sweden)

    Janice Kal Van Tam, Koichiro Uto, Mitsuhiro Ebara, Stefania Pagliari, Giancarlo Forte and Takao Aoyagi

    2012-01-01

    Full Text Available The acknowledged ability of synthetic materials to induce cell-specific responses regardless of biological supplies provides tissue engineers with the opportunity to find the appropriate materials and conditions to prepare tissue-targeted scaffolds. Stem and mature cells have been shown to acquire distinct morphologies in vitro and to modify their phenotype when grown on synthetic materials with tunable mechanical properties. The stiffness of the substrate used for cell culture is likely to provide cells with mechanical cues mimicking given physiological or pathological conditions, thus affecting the biological properties of cells. The sensitivity of cells to substrate composition and mechanical properties resides in multiprotein complexes called focal adhesions, whose dynamic modification leads to cytoskeleton remodeling and changes in gene expression. In this study, the remodeling of focal adhesions in human mesenchymal stem cells in response to substrate stiffness was followed in the first phases of cell–matrix interaction, using poly-ε-caprolactone planar films with similar chemical composition and different elasticity. As compared to mature dermal fibroblasts, mesenchymal stem cells showed a specific response to substrate stiffness, in terms of adhesion, as a result of differential focal adhesion assembly, while their multipotency as a bulk was not significantly affected by matrix compliance. Given the sensitivity of stem cells to matrix mechanics, the mechanobiology of such cells requires further investigations before preparing tissue-specific scaffolds.

  5. Nanosheet based SnO{sub 2} assembles grown on a flexible substrate

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Siwen; Yin, Bosi; Jiao, Yang; Liu, Yang; Qu, Fengyu; Wu, Xiang, E-mail: wuxiang05@gmail.com

    2014-06-01

    Novel SnO{sub 2} assembles by many nanosheets are successfully synthesized on a flexible carbon cloth through a chemical vapor deposition (CVD) method at 750 °C. The as-prepared products are characterized by using a series of test techniques, including scanning electron microscope (SEM), X-ray diffraction (XRD), Raman spectrum and the spectrophotometer. A possible growth mechanism is temporarily proposed. Photoluminescence (PL) spectrum of the as-prepared SnO{sub 2} product shows a weak blue emission peak at 436 nm and a strong green emission peak centered at 526 nm, which may be ascribed to the defects associated with the structures.

  6. Photo- and Electrochromic Properties of Activated Reactive Evaporated MoO3 Thin Films Grown on Flexible Substrates

    Directory of Open Access Journals (Sweden)

    K. Hari Krishna

    2008-01-01

    Full Text Available The molybdenum trioxide (MoO3 thin films were grown onto ITO-coated flexible Kapton substrates using plasma assisted activated reactive evaporation technique. The film depositions were carried out at constant glow power and oxygen partial pressures of 8 W and 1×10−3 Torr, respectively. The influence of substrate temperature on the microstructural and optical properties was investigated. The MoO3 thin films prepared at a substrate temperature of 523 K were found to be composed of uniformly distributed nanosized grains with an orthorhombic structure of α-MoO3. These nanocrystalline MoO3 thin films exhibited higher optical transmittance of about 80% in the visible region with an evaluated optical band gap of 3.29 eV. With the insertion of 12.5 mC/cm2, the films exhibited an optical modulation of 40% in the visible region with coloration efficiency of 22 cm2/C at the wavelength of 550 nm. The MoO3 films deposited at 523 K demonstrated better photochromic properties and showed highest color center concentration for the irradiation time of 30 minutes at 100 mW/cm2.

  7. Linear Low Density Polyethylene (LLDPE) as Flexible Substrate for Wrist and Arm Antennas in C-Band

    Science.gov (United States)

    Gogoi, Pragyan Jyoti; Bhattacharyya, Satyajib; Bhattacharyya, Nidhi S.

    2015-04-01

    This paper focuses on the development and study of linear low density polyethylene as a flexible substrate for conformal antennas for body-worn applications. Thermal stability, tensile strength and elongation at break of the substrate were studied. The permittivity of the substrate was 2.2 and tan δ was found to be 0.0003 at 6 GHz. Since the antenna is being developed for wrist and arm wearing in C-band, the performance of the antenna, such as the S 11 parameter and radiation pattern, were studied with different bending axes and with bending curvature approximating that of the arm and wrist. The performance of a 6 GHz rectangular patch antenna with bending was found to be consistent with the flat profile antenna at the same frequency. A maximum shift in the resonant frequency of ˜20 MHz was observed. The -10 dB bandwidth and directivity of the antenna did not change much with bending. The maximum bending radius in the present study is 10 mm, and S 11 was found to be -17.53 dB at 5.94 GHz and -14.02 dB at 6.06 GHz for a bending axis parallel to the radiating and non-radiating edge, respectively.

  8. Infrared blocking, microwave and terahertz low-loss transmission AlN films grown on flexible polymeric substrates

    Science.gov (United States)

    Rudenko, E.; Tsybrii, Z.; Sizov, F.; Korotash, I.; Polotskiy, D.; Skoryk, M.; Vuichyk, M.; Svezhentsova, K.

    2017-04-01

    Aluminum nitride (AlN) film coatings on flexible substrates (polymeric Teflon, Mylar) have been obtained using a hybrid helicon-arc ion-plasma deposition technique with high adhesion of coatings. Studies of optical, morphological, and structural properties of AlN films have been carried out. It was found that AlN coatings on Teflon and Mylar thin-film substrates substantially suppress transmission of infrared (IR) radiation within the spectral range λ ˜ 5-20 μm at certain technological parameters and thickness of AlN. Transmission in THz regions by using quasioptics attains T ≈ 79%-95%, and losses measured in the channels within the microwave region 2 to 36 GHz are <0.06 dB. The obtained composite structures (AlN coatings on Teflon and Mylar thin-film substrates), due to a high thermal conductivity of AlN, could be used as efficient blocking structures in the infrared spectral range ("infrared stealth") withdrawing the heat from filters warmed by IR radiation. At the same time, they can be used as the transparent ones in the microwave and THz regions, which can be important for low-temperature detector components of navigation, positioning, and telecommunication systems due to reducing the background noise.

  9. Shear Strength of Conductive Adhesive Joints on Rigid and Flexible Substrates Depending on Adhesive Quantity

    Science.gov (United States)

    Hirman, Martin; Steiner, Frantisek

    2016-05-01

    This article deals with the impact of electrically conductive adhesive quantity on the shear strength of joints glued by adhesives "EPO-TEKⓇ H20S" and "MG8331S" on three types of substrates (FR-4, MELINEXⓇST504, DuPont™ PyraluxⓇAC). These joints were made by gluing chip resistors 1206, 0805 and 0603, with two curing profiles for each adhesive. Different thicknesses of stencil and reductions in the size of the hole in stencils were used for this experiment. These differences have an effect on the quantity of conductive adhesives which must be used on the samples. Samples were measured after the curing process by using a shear strength test applied by the device LabTest 3.030. This article presents the effects of different curing profiles, various types of substrates, and different quantities of adhesives on the mechanical strength of the joint.

  10. Nature Degradable, Flexible, and Transparent Conductive Substrates from Green and Earth-Abundant Materials.

    Science.gov (United States)

    Yang, Bing; Yao, Chunhua; Yu, Yanhao; Li, Zhaodong; Wang, Xudong

    2017-07-10

    The rapid development of wearable and disposable electronic devices and the rising awareness of environmental sustainability impose growing new demands on the nature degradability of current electronic and energy systems. Here we report a new type of flexible transparent conductive paper completely made from green and earth abundant materials which are also fully degradable and recyclable. Aluminum-doped zinc oxide (AZO) was deposited by low-temperature atomic layer deposition (ALD) as the transparent conductive oxide (TCO) layer on transparent cellulose nanofibril (CNF) papers. The mesoporous structure of the CNF paper rendered strong adhesion of the AZO layer and exhibited excellent mechanical integrity and electrical conductivity within a wide range of tensile and compressive strains. The AZO-CNF paper could be completely dissolved in warm city water after one-hour stirring, demonstrating an excellent nature degradability. A flexible and transparent triboelectric nanogenerator (TENG) was further fabricated using such AZO-CNF papers with a performance that was comparable to other synthetic polymer-based systems. This work illustrated a new and promising strategy of utilizing 100% green and degradable materials in novel electronic and energy harvesting devices.

  11. Structural and Optical Properties of Sputtered Cadmium Telluride Thin Films Deposited on Flexible Substrates for Photovoltaic Applications.

    Science.gov (United States)

    Song, Woochang; Lee, Kiwon; Kim, Donguk; Lee, Jaehyeong

    2016-05-01

    Cadmium telluride (CdTe) is a photovoltaic technology based on the use of thin films of CdTe to absorb and convert sunlight into electricity. In this paper, polycrystalline CdTe thin films were deposited using radio frequency magnetron sputtering onto flexible substrates including polyimide and molybdenum foil. The structural and optical properties of the films grown at various sputtering pressures were investigated using X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), and UV/Nis/NIR spectrophotometry. The sputtering pressure was found to have significant effects on the structural properties, including crystallinity, preferential orientation, and microstructure. Deterioration of the optical properties of CdTe thin films were observed at high sputtering pressure.

  12. Influence of intra-molecular flexibility on the elastic property of double-stranded DNA film on a substrate

    Science.gov (United States)

    Wu, Jun-Zheng; Meng, Wei-Lie; Tang, Heng-Song; Zhang, Neng-Hui

    2017-05-01

    DNA film self-assembled or nanografted on a substrate, as a kind of soft matter, consists of fixed DNA chains endowed with negative charges and an aqueous solution full of cations, anions and water molecules. Their thermal/electrical/mechanical properties are closely related to the complex biodetection signals in nano-/micro-scale biosensors and other new genome technologies. This makes it important to properly characterize these properties. In this paper, the effect of flexible micro-scale configurations on the elastic moduli of DNA films is investigated. First, illuminated by Qiu’s sphere model, an alternative bead-chain model in terms of the Yukawa potential is presented for flexible intra-DNA configurations to describe interactions between DNA fragments. The effective charges of coarse-grained DNA beads could be derived, in which the empirical parameters are identified by curve fitting with Qiu’s experimental data. Second, the updated mesoscopic bead-chain model and the thought experiment of a continuum compression bar are used to compare the elastic moduli of double-stranded DNA (dsDNA) films prepared by self-assembling and nanografting techniques. Configurational sampling is achieved via Monte Carlo simulation. Our predictions quantitatively or qualitatively agree well with the relevant experiments on the effective charge of dsDNA from low to moderate monovalent counterion concentration, immobilization deflection of single-stranded DNA (ssDNA) or dsDNA microcantilever with the variation of salt concentration, and elastic modulus of ssDNA film in the air. The results reveal that different solution environment stimulates the diverse mechanical properties of dsDNA film on a substrate, and the end effect (i.e. terminal group effect) makes self-assembling dsDNA film stiffer in the sense of the same average packing density.

  13. A suitable for large scale production, flexible and transparent surface-enhanced Raman scattering substrate for in situ ultrasensitive analysis of chemistry reagents

    Science.gov (United States)

    Chen, P. X.; Shang, S. B.; Hu, L. T.; Liu, X. Y.; Qiu, H. W.; Li, C. H.; Huo, Y. Y.; Jiang, S. Z.; Yang, C.

    2016-09-01

    In this paper, a high cost-performance surface-enhanced Raman scattering (SERS) flexible substrate is demonstrated, which endowed with excellent optical transparency, high SERS activity and large scale. This SERS flexible substrate of Ag/Cu/Polyethylene Terephthalate (PET) was prepared by replacing Cu atoms with Ag atoms in situ on Cu nano-film. The Ag/Cu/PET flexible substrate shows high sensitivity in SERS detection and the minimum detected concentration of R6G can reach 10-10 M. In addition, the residual methylene blue (MB) on a fish surface was selected as the analyte, the results no doubt shows the potential of SERS technology application in food detection.

  14. High-concentration copper nanoparticles synthesis process for screen-printing conductive paste on flexible substrate

    Science.gov (United States)

    Tam, Sze Kee; Ng, Ka Ming

    2015-12-01

    This study presents a method for the synthesis of copper nanoparticles, which are poised to replace silver nanoparticles in some application areas of printed electronics. This method offers three advantages. Firstly, copper loading in the synthesis reaction can be as high as 1 M, offering high productivity in large-scale production. Secondly, the size of the copper nanoparticles can be controlled from 12 to 99 nm. Thirdly, the surface polarity of the particles can be modified. Thus, a tailor-made product can be synthesized. The synthesis of copper nanoparticles coated with various capping agents, including dodecanethiol, lauric acid, nonanoic acid, polyacrylic acid, and polyvinyl pyrrolidone, was demonstrated. The nonanoic acid-coated copper nanoparticles were formulated as a screen-printing conductive paste. The particles were readily dispersed in terpineol, and the paste could be screen printed onto flexible polyester. The electrical resistivity of patterns after a low-temperature (120 °C) sintering treatment was around 5.8 × 10-5 Ω cm.

  15. High-concentration copper nanoparticles synthesis process for screen-printing conductive paste on flexible substrate

    Energy Technology Data Exchange (ETDEWEB)

    Tam, Sze Kee; Ng, Ka Ming, E-mail: kekmng@ust.hk [The Hong Kong University of Science and Technology, Department of Chemical and Biomolecular Engineering (Hong Kong)

    2015-12-15

    This study presents a method for the synthesis of copper nanoparticles, which are poised to replace silver nanoparticles in some application areas of printed electronics. This method offers three advantages. Firstly, copper loading in the synthesis reaction can be as high as 1 M, offering high productivity in large-scale production. Secondly, the size of the copper nanoparticles can be controlled from 12 to 99 nm. Thirdly, the surface polarity of the particles can be modified. Thus, a tailor-made product can be synthesized. The synthesis of copper nanoparticles coated with various capping agents, including dodecanethiol, lauric acid, nonanoic acid, polyacrylic acid, and polyvinyl pyrrolidone, was demonstrated. The nonanoic acid-coated copper nanoparticles were formulated as a screen-printing conductive paste. The particles were readily dispersed in terpineol, and the paste could be screen printed onto flexible polyester. The electrical resistivity of patterns after a low-temperature (120 °C) sintering treatment was around 5.8 × 10{sup −5} Ω cm.Graphical Abstract.

  16. Organic ferroelectric memory devices with inkjet-printed polymer electrodes on flexible substrates

    KAUST Repository

    Bhansali, Unnat Sampatraj

    2013-05-01

    Drop-on-demand piezoelectric inkjet-printing technique has been used to fabricate a functional cross-bar array of all-organic ferroelectric memory devices. The polymer-ferroelectric-polymer device consists of a ferroelectric copolymer P(VDF-TrFE) film sandwiched between inkjet-patterned, continuous, orthogonal lines of PEDOT:PSS polymer as the bottom and top electrodes. These devices exhibit well-saturated hysteresis curves with a maximum remnant polarization (Pr) = 6.7 μC/cm2, coercive field (E c) = 55 MV/m and a peak capacitance density of 45 nF/cm2. Our polarization fatigue measurements show that these devices retain ∼100% and 45% of their initial Pr values after 103 and 10 5 stress cycles, respectively. The overall performance and polarization retention characteristics of these ferroelectric capacitors with inkjet-printed polymer electrodes are comparable to metal and spin-cast polymer electrodes suggesting their potential use in large-area flexible electronics. © 2013 Elsevier Ltd. All rights reserved.

  17. Electrical and mechanical stability of aluminum-doped ZnO films grown on flexible substrates by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Luka, G., E-mail: gluka@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Witkowski, B.S.; Wachnicki, L.; Jakiela, R. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Virt, I.S. [University of Rzeszow, Rzeszow (Poland); Drohobych Ivan Franko State Pedagogical University, Drohobych (Ukraine); Andrzejczuk, M.; Lewandowska, M. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw (Poland); Godlewski, M. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Department of Mathematics and Natural Sciences, College of Science, Cardinal Stefan Wyszynski University, Warsaw (Poland)

    2014-08-01

    Highlights: • Transparent and conductive ZnO:Al films were grown by atomic layer deposition. • The films were grown on flexible substrates at low growth temperatures (110–140 °C). • So-obtained films have low resistivities, of the order of 10{sup −3} Ω cm. • Bending tests indicated a critical bending radius of ≈1.2 cm. • Possible sources of the film resistivity changes upon bending are proposed. - Abstract: Aluminum-doped zinc oxide (AZO) films were grown on polyethylene terephthalate (PET) substrates by atomic layer deposition (ALD) at low deposition temperatures (110–140 °C). The films have low resistivities, ∼10{sup −3} Ω cm, and high transparency (∼90%) in the visible range. Bending tests indicated a critical bending radius of ≈1.2 cm, below which the resistivity changes became irreversible. The films deposited on PET with additional buffer layer are more stable upon bending and temperature changes.

  18. Manufacturing of polymer optical waveguides using self-assembly effect on pre-conditioned 3D-thermoformed flexible substrates

    Science.gov (United States)

    Hoffmann, Gerd-Albert; Wolfer, Tim; Zeitler, Jochen; Franke, Jörg; Suttmann, Oliver; Overmeyer, Ludger

    2017-02-01

    Optical data communication is increasingly interesting for many applications in industrial processes. Therefore mass production is required to meet the requested price and lot sizes. Polymer optical waveguides show great promises to comply with price requirements while providing sufficient optical quality for short range data transmission. A high efficient fabrication technology using polymer materials could be able to create the essential backbone for 3D-optical data transmission in the future. The approach for high efficient fabrication technology of micro optics described in this paper is based on a self-assembly effect of fluids on preconditioned 3D-thermoformed polymer foils. Adjusting the surface energy on certain areas on the flexible substrate by flexographic printing mechanism is presented in this paper. With this technique conditioning lines made of silicone containing UV-varnish are printed on top of the foils and create gaps with the exposed substrate material in between. Subsequent fabrication processes are selected whether the preconditioned foil is coated with acrylate containing waveguide material prior or after the thermoforming process. Due to the different surface energy this material tends to dewet from the conditioning lines. It acts like regional barriers and sets the width of the arising waveguides. With this fabrication technology it is possible to produce multiple waveguides with a single coating process. The relevant printing process parameters that affect the quality of the generated waveguides are discussed and results of the produced waveguides with width ranging from 10 to 300 μm are shown.

  19. Electrical performance of polymer ferroelectric capacitors fabricated on plastic substrate using transparent electrodes

    KAUST Repository

    Bhansali, Unnat Sampatraj

    2012-09-01

    Polymer-based flexible ferroelectric capacitors have been fabricated using a transparent conducting oxide (ITO) and a transparent conducting polymer (PEDOT:PSS). It is found that the polarization fatigue performance with transparent oxide electrodes exhibits a significant improvement over the polymer electrodes (20% vs 70% drop in polarization after 10 6 cycles). This result can be explained based on a charge injection model that is controlled by interfacial band-offsets, and subsequent pinning of ferroelectric domain walls by the injected carriers. Furthermore, the coercive field (E c) of devices with our polymer electrodes is nearly 40% lower than reported values with similar polymer electrodes. Surprisingly, this difference was found to be related to the dry etching process used to define the top electrodes, which is reported for the first time by this group. The temperature dependence of relative permittivity of both devices shows a typical first order ferroelectric-to-paraelectric phase transition, but with a reduced Curie temperature compared to reference devices fabricated on Pt. © 2012 Elsevier B.V. All rights reserved.

  20. A finite element formulation for modeling dynamic wetting on flexible substrates and in deformable porous media.

    Energy Technology Data Exchange (ETDEWEB)

    Schunk, Peter Randall; Cairncross, Richard A. (Drexel University, Philadelphia, PA); Madasu, S. (Drexel University, Philadelphia, PA)

    2004-03-01

    This report summarizes research advances pursued with award funding issued by the DOE to Drexel University through the Presidential Early Career Award (PECASE) program. Professor Rich Cairncross was the recipient of this award in 1997. With it he pursued two related research topics under Sandia's guidance that address the outstanding issue of fluid-structural interactions of liquids with deformable solid materials, focusing mainly on the ubiquitous dynamic wetting problem. The project focus in the first four years was aimed at deriving a predictive numerical modeling approach for the motion of the dynamic contact line on a deformable substrate. A formulation of physical model equations was derived in the context of the Galerkin finite element method in an arbitrary Lagrangian/Eulerian (ALE) frame of reference. The formulation was successfully integrated in Sandia's Goma finite element code and tested on several technologically important thin-film coating problems. The model equations, the finite-element implementation, and results from several applications are given in this report. In the last year of the five-year project the same physical concepts were extended towards the problem of capillary imbibition in deformable porous media. A synopsis of this preliminary modeling and experimental effort is also discussed.

  1. The electrodeposition of multilayers on a polymeric substrate in Flexible Organic Light Emitting Diode (OLED)

    Science.gov (United States)

    Guedes, Andre F. S.; Guedes, Vilmar P.; Tartari, Simone; Cunha, Idaulo Jose

    2016-09-01

    The development of Organic Light Emitting Diode (OLED), using an optically transparent substrate material and organic semiconductor materials, has been widely utilized by the electronic industry when producing new technological products. The OLED are the base Poly(3,4-ethylenedioxythiophene), PEDOT, Poly(p-phenylenevinylene), PPV, and Polyaniline, PANI, were deposited in Indium Tin Oxide, ITO, and characterized by UV-Visible Spectroscopy (UV-Vis), Optical Parameters (OP) and Scanning Electron Microscopy (SEM). In addition, the thin film obtained by the deposition of PANI, prepared in perchloric acid solution, was identified through PANI-X1. The result obtained by UV-Vis has demonstrated that the PET/ITO/PEDOT/PPV/PANI-X1/Al layer does not have displacement of absorption for wavelengths greaters after spin-coating and electrodeposition. Thus, the spectral irradiance of the OLED informed the irradiance of 100 W/m2, and this result, compared with the standard Light Emitting Diode (LED), has indicated that the OLED has higher irradiance. After 1200 hours of electrical OLED tests, the appearance of nanoparticles visible for images by SEM, to the migration process of organic semiconductor materials, was present, then. Still, similar to the phenomenon of electromigration observed in connections and interconnections of microelectronic devices, the results have revealed a new mechanism of migration, which raises the passage of electric current in OLED.

  2. Edge isolation of transparent conductive polymer (TCP) thin films on flexible substrates using UV laser ablation.

    Science.gov (United States)

    Hsiao, Wen-Tse; Tseng, Shih-Feng; Huang, Kuo-Cheng; Chiang, Donyau; Chen, Ming-Fei

    2012-06-01

    The purpose of this study was to directly use the writing techniques for the complex electrode edge isolation of transparent conductive polymer (TCP) thin films by a nanosecond pulsed UV laser processing system. The processing parameters including the laser pulse energy, the pulse repetition frequency, and the scan speed of galvanometers were examined to ablate the TCP films deposited on polyethylene terephtalate substrates of 188 microm thick. The thickness of TCP films was approximately 20 nm. The laser pulse repetition frequency and the scan speed of galvanometers were applied to calculate the overlapping rate of laser spots and to discuss the patterning region quality. Surface morphology, edge quality, and width and depth of edge isolated patterning structures after laser ablation process were measured by a three-dimensional confocal laser scanning microscope. In addition, the electrical conductivity of ablated TCP films was measured by a four-point probes instrument. After isolated line patterning was formed, the ablated TCP films with a better edge quality were obtained directly when the overlapping rate of laser spots, the scan speed, and the pulse repetition rate were 83.3%, 200 mm/s, and 40 kHz, respectively. The better surface morphology of electrode pattern structures was also obtained when the scan speed and the pulse repetition rate were 500 mm/s and 40 kHz, respectively.

  3. Experimental assessment of SU-8 optical waveguides buried in plastic substrate for optical interconnections.

    Science.gov (United States)

    Hamid, Hanan H; Fickenscher, Thomas; Thiel, David V

    2015-08-01

    Multimode polymer waveguides have been developed to create low-cost, high-speed on-board optical interconnects. Buried optical waveguides made from SU-8 in a polymethyl methacrylate polymer (PMMA) substrate covered with a thin PMMA sheet are a low-cost option for electro-optical interconnects. The propagation losses for a 600  μm×600  μm straight waveguide were 1.96, 1.32, and 1.39  dB/cm, respectively, at three different wavelengths (850, 1310, and 1550 nm). The bending loss for a 15 mm bending radius is as high as 6  dB/cm. Transition and radiation losses dominate overall loss when the bending radius is less than 30 mm. The waveguide was excited using a multimode 850 nm VCSEL transmitter and detected using butt-coupled and lens-coupled receivers. The coupling loss was about 1 dB for the butt-coupling technique and 2 dB for lens coupling. The response bandwidth and the group delay of direct modulated (IF) signal were independent of the channel waveguide for communication speeds up to more than 3 GHz. This technique is viable for low-cost, short-length buried optical waveguides.

  4. "Shrink-to-fit" superhydrophobicity: thermally-induced microscale wrinkling of thin hydrophobic multilayers fabricated on flexible shrink-wrap substrates.

    Science.gov (United States)

    Manna, Uttam; Carter, Matthew C D; Lynn, David M

    2013-06-11

    An approach to the design of flexible superhydrophobic surfaces based on thermally induced wrinkling of thin, hydrophobic polymer multilayers on heat-shrinkable polymer films is reported. This approach exploits shrinking processes common to "heat-shrink" plastics, and can thus be used to create "shrink-to-fit" superhydrophobic coatings on complex surfaces, manipulate the dimensions and densities of patterned features, and promote heat-activated repair of full-thickness defects.

  5. Flexible Ablators

    Science.gov (United States)

    Stackpoole, Margaret M. (Inventor); Ghandehari, Ehson M. (Inventor); Thornton, Jeremy J. (Inventor); Covington, Melmoth Alan (Inventor)

    2017-01-01

    A low-density article comprising a flexible substrate and a pyrolizable material impregnated therein, methods of preparing, and devices using the article are disclosed. The pyrolizable material pyrolizes above 350 C and does not flow at temperatures below the pyrolysis temperature. The low-density article remains flexible after impregnation and continues to remain flexible when the pyrolizable material is fully pyrolized.

  6. A comparative study of via drilling and scribing on PEN and PET substrates for flexible electronic applications using excimer and Nd:YAG laser sources

    NARCIS (Netherlands)

    Mandamparambil, R.; Fledderus, H.; Brand, J. van den; Saalmink, M.; Kusters, R.; Podprocky, T.; Steenberge, G. van; Baets, J. de; Dietzel, A.H.

    2009-01-01

    A study on via drilling and channel scribing on PEN and PET substrates for flexible electronic application is discussed in this paper. For the experiments, both KIF excimer laser (248 nm) and frequency tripled Nd:YAG (355 nm) laser are used. Different measurement techniques like optical microscopy,

  7. Alternative sodium sources for Cu(In,Ga)Se{sub 2} thin-film solar cells on flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Wuerz, R., E-mail: roland.wuerz@zsw-bw.de [Zentrum fuer Sonnenenergie-und Wasserstoff-Forschung Baden-Wuerttemberg, Industriestrasse 6, 70565 Stuttgart (Germany); Eicke, A.; Kessler, F. [Zentrum fuer Sonnenenergie-und Wasserstoff-Forschung Baden-Wuerttemberg, Industriestrasse 6, 70565 Stuttgart (Germany); Rogin, P.; Yazdani-Assl, O. [Leibniz-Institut fuer Neue Materialien gGmbH, Campus D2 2, 66123 Saarbruecken (Germany)

    2011-08-31

    Sodium (Na) is an important doping element for Cu(In,Ga)Se{sub 2} (CIGS) solar cells. However, when using Na-free flexible substrates like steel foil or polyimide film, it is necessary to ensure an efficient supply of sodium to achieve high cell efficiencies. The common incorporation methods for Na on these Na-free substrates are either to deposit a Na-containing precursor layer (e.g. NaF) onto the molybdenum (Mo) back contact prior to CIGS growth or to coevaporate a Na compound during CIGS growth. Another way is to incorporate sodium after CIGS growth by a post-deposition treatment with NaF. In this work, we tested two alternative Na doping methods which are well suited for a production line due to their easy controllability. One approach is to dope the molybdenum target with Na. With Na-doped Mo layers (Mo:Na) as the back contact, we could achieve efficiencies of 13.1% both on titanium (Ti) and stainless Cr steel foil using a single-stage inline CIGS process. With a low-temperature single-stage CIGS process on polyimide (PI) we reached an efficiency of 11.2% using a Mo:Na back contact. Another doping method involves sol-gel-deposited silicon oxide layers which contain Na (SiO{sub x}:Na). We have successfully deposited these sol-gel layers onto stainless steel foil by a roll-to-roll (R2R) method with short annealing times as needed in production. With these SiO{sub x}:Na layers we could achieve efficiencies of 13.7% on stainless steel foil and 11.5% on mild steel sheet using a single-stage inline CIGS process.

  8. Growth, Structural and Optical Characterization of ZnO Nanotubes on Disposable-Flexible Paper Substrates by Low-Temperature Chemical Method

    Directory of Open Access Journals (Sweden)

    M. Y. Soomro

    2012-01-01

    Full Text Available We report the synthesis of vertically aligned ZnO nanotubes (NTs on paper substrates by low-temperature hydrothermal method. The growth of ZnO NTs on the paper substrate is discussed; further, the structural and optical properties are investigated by scanning electron microscope (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, energy-dispersive X-ray spectroscopy (EDS, and cathodoluminescence (CL, and it was found that the ZnO NTs on paper substrate fulfill the structural and optical properties of ZnO NTs grown on other conventional substrates. This will be more beneficial in future usage of ZnO NTs in different fields and applications. Particularly, this approach opens the ways in research and development for high volume manufacturing of low-cost, flexible optoelectronics devices on disposable paper substrates and can be used in the future miniaturization trends.

  9. Thickness dependence of magnetic anisotropy and domains in amorphous Co40Fe40B20 thin films grown on PET flexible substrates

    Science.gov (United States)

    Tang, Zhenhua; Ni, Hao; Lu, Biao; Zheng, Ming; Huang, Yong-An; Lu, Sheng-Guo; Tang, Minghua; Gao, Ju

    2017-03-01

    The amorphous Co40Fe40B20 (CoFeB) films (5-200 nm in thickness) were grown on flexible polyethylene terephthalate (PET) substrates using the DC magnetron-sputtering method. The thickness dependence of structural and magnetic properties of flexible CoFeB thin films was investigated in detail. The in-plane uniaxial magnetic anisotropy induced by strain as a function of thickness was obtained in flexible CoFeB thin films, and a critical thickness of 150 nm for in-plane magnetic anisotropy was observed. Moreover, the domains and the uniaxial anisotropy as a function of angular direction of applied magnetic field were characterized. The results show potential for designing CoFeB-based flexible spintronic devices in which the physical parameters could be tailored by controlling the thickness of the thin film.

  10. Cost and Reliability Improvement for CIGS-Based PV on Flexible Substrate: May 24, 2006 -- July 31, 2010

    Energy Technology Data Exchange (ETDEWEB)

    Wiedeman, S.

    2011-05-01

    Global Solar Energy rapidly advances the cost and performance of commercial thin-film CIGS products using roll-to-roll processing on steel foil substrate in compact, low cost deposition equipment, with in-situ sensors for real-time intelligent process control. Substantial increases in power module efficiency, which now exceed 13%, are evident at GSE factories in two countries with a combined capacity greater than 75 MW. During 2009 the average efficiency of cell strings (3780 cm2) was increased from 7% to over 11%, with champion results exceeding 13% Continued testing of module reliability in rigid product has reaffirmed extended life expectancy for standard glass product, and has qualified additional lower-cost methods and materials. Expected lifetime for PV in flexible packages continues to increase as failure mechanisms are elucidated, and resolved by better methods and materials. Cost reduction has been achieved through better materials utilization, enhanced vendor and material qualification and selection. The largest cost gains have come as a result of higher cell conversion efficiency and yields, higher processing rates, greater automation and improved control in all process steps. These improvements are integral to this thin film PV partnership program, and all realized with the 'Gen2' manufacturing plants, processes and equipment.

  11. Preparing of Highly Conductive Patterns on Flexible Substrates by Screen Printing of Silver Nanoparticles with Different Size Distribution

    Science.gov (United States)

    Ding, Jin; Liu, Jun; Tian, Qingyong; Wu, Zhaohui; Yao, Weijing; Dai, Zhigao; Liu, Li; Wu, Wei

    2016-09-01

    A facile one-step polyol method is employed to synthesize the Ag nanoparticles (NPs) in large scale. The Ag NPs with different average diameter (from 52 to 120 nm) and particle size distribution are prepared by changing the mass ratio of AgNO3 and PVP. Furthermore, the as-obtained Ag NPs are prepared as conductive inks, which could be screen printed on various flexible substrates and formed as conductive patterns after sintering treatment. During the reaction process, PVP is used as the capping reagent for preventing the agglomeration of Ag NPs, and the influence of the mass ratio of AgNO3 and PVP to the size distribution of Ag NPs is investigated. The results of electronic properties reveal that the conductivity of printed patterns is highly dependent on the size distribution of as-obtained Ag NPs. Among all the samples, the optimal conductivity is obtained when the mass ratio of AgNO3 and PVP is 1:0.4. Subsequently, the sintering time and temperature are further investigated for obtaining the best conductivity; the optimal electrical resistivity value of 3.83 μΩ · cm is achieved at 160 °C for 75 min, which is close to the resistivity value of the bulk silver (1.58 μΩ · cm). Significantly, there are many potential advantages in printed electronics applications because of the as-synthesized Ag NPs with a low sintering temperature and low electrical resistivity.

  12. Metal oxide nanostructures synthesized on flexible and solid substrates and used for catalysts, UV detectors, and chemical sensors

    Science.gov (United States)

    Willander, Magnus; Sadollahkhani, Azar; Echresh, Ahmad; Nur, Omer

    2014-03-01

    In this paper we demonstrate the visibility of the low temperature chemical synthesis for developing device quality material grown on flexible and solid substrates. Both colorimetric sensors and UV photodetectors will be presented. The colorimetric sensors developed on paper were demonstrated for heavy metal detection, in particular for detecting copper ions in aqueous solutions. The demonstrated colorimetric copper ion sensors developed here are based on ZnO@ZnS core-shell nanoparticles (CSNPs). These sensors demonstrated an excellent low detection limit of less than 1 ppm of copper ions. Further the colorimetric sensors operate efficiently in a wide pH range between 4 and 11, and even in turbulent water. The CSNPs were additionally used as efficient photocatalytic degradation element and were found to be more efficient than pure ZnO nanoparticles (NPs). Also p-NiO/n-ZnO thin film/nanorods pn junctions were synthesized by a two-step synthesis process and were found to act as efficient UV photodetectors. Additionally we show the effect of the morphology of different CuO nanostructures on the efficiency of photo catalytic degradation of Congo red organic dye.

  13. Design and development of plasmonic nanostructured electrodes for ITO-free organic photovoltaic cells on rigid and highly flexible substrates

    Science.gov (United States)

    Richardson, Beau J.; Zhu, Leize; Yu, Qiuming

    2017-04-01

    Indium tin oxide (ITO) is the most common transparent electrode used in organic photovoltaics (OPVs), yet limited indium reserves and poor mechanical properties make it non-ideal for large-scale OPV production. To replace ITO, we designed, fabricated, and deployed plasmonic nanostructured electrodes in inverted OPV devices. We found that active layer absorption is significantly impacted by ZnO thickness which affects the optical field distribution inside the resonant cavity formed between the plasmonic nanostructured electrode and top electrode. High quality Cr/Au nanostructured electrodes were fabricated by nanoimprint lithography and deployed in ITO-free inverted devices on glass. Devices with thinner ZnO showed a PCE as high as 5.70% and higher J SC’s than devices on thicker ZnO, in agreement with finite-difference time-domain simulations. In addition, as the active layer was made optically thin, ITO-based devices showed diminished J SC while the resonant cavity effect from plasmonic nanostructured electrodes retained J SC. Preliminary ITO-free, flexible devices on PET showed a PCE of 1.82% and those fabricated on ultrathin and conformable Parylene substrates yielded an initial PCE over 1%. The plasmonic electrodes and device designs in this work show promise for developing highly functioning conformable devices that can be applied to numerous needs for lightweight, ubiquitous power generation.

  14. Thermo-mechanical evolution of ternary Bi-Sn-In solder micropowders and nanoparticles reflowed on a flexible PET substrate

    Science.gov (United States)

    Kim, Sang Hoon; Yang, Dong-Yeol; Kim, Yong-Jin; Min, Taesik; Choi, Joonphil; Yun, Jaecheol; Nguyen, Van Luong; Kim, Ki Bong; Kim, Young Ja; Lee, Jun Hong; Kim, Yang Do; Yang, Sangsun

    2017-09-01

    Ternary Bi-Sn-In micropowders and nanoparticles were prepared as a composite solder material via a gas atomization process and a chemical reduction method, respectively. The nanoparticles, with a 71.1 °C melting temperature, entered among the intervals of the higher melting temperature (79.4 °C) micropowders, and then reflowed at 110 °C on a flexible polyethylene terephthalate (PET) substrate. This considerably increased the thermal diffusivity of the nanoparticles to refine the surface morphology of the solder bumps. Their adhesion strength also increased from an average shear force of 0.33-0.43 N by viscosity improvement, afforded to the reinforcement of 5.0 wt.% added nanoparticles. However, the adhesion strength (0.25 N average shear force) of the composite solder bumps deteriorated at 15.0 wt.% added nanoparticles and resulted in a high electrical resistivity (72.53 ± 8.54 μΩ cm) due to the formation of their surface-oxidized phases.

  15. Flexible Electronics Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Flexible Electronics Research Facility designs, synthesizes, tests, and fabricates materials and devices compatible with flexible substrates for Army information...

  16. Transparent, flexible surface enhanced Raman scattering substrates based on Ag-coated structured PET (polyethylene terephthalate) for in-situ detection

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Zewen, E-mail: zuozewen@mail.ahnu.edu.cn; Zhu, Kai; Gu, Chuan; Wen, Yibing; Cui, Guanglei; Qu, Jun

    2016-08-30

    Highlights: • Transparent, flexible SERS substrates were prepared using techniques compatible with well-established silicon device technologies. • The SERS substrates exhibit high sensitivity and good reproducibility. • The high performance is related with the quasi-three-dimensional structure of the PET. • In-situ detection of analyte on irregular objects was achieved by this SERS substrate. - Abstract: Transparent, flexible surface-enhanced Raman scattering (SERS) substrates were fabricated by metalization of structured polyethylene terephthalate (PET) sheets. The resultant Ag-coated structured PET SERS substrates were revealed to be highly sensitive with good reproducibility and stability, an enhancement factor of 3 × 10{sup 6} was acquired, which can be attributed mainly to the presence of plentiful multiple-type hot spots within the quasi-three-dimensional surface of the structured PET obtained by oxygen plasma etching. In addition, detections of model molecules on fruit skin were also carried out, demonstrating the great potential of the Ag-coated structured PET in in-situ detection of analyte on irregular objects. Importantly, the technique used for the preparation of such substrate is completely compatible with well-established silicon device technologies, and large-area fabrication with low cost can be readily realized.

  17. Fabrication of the flexible nanogenerator from BTO nanopowders on graphene coated PMMA substrates by sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Sankar Ganesh, R. [Department of Physics and Nanotechnology, SRM University, Kattankullathur, Chennai, 603203, Tamil Nadu (India); Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka, 432-8011 (Japan); Sharma, Sanjeev K., E-mail: sksharma@dongguk.edu [Department of Semiconductor Science, Dongguk University-Seoul, Jung-gu, Seoul, 04620 (Korea, Republic of); Abinnas, N. [Department of Physics and Nanotechnology, SRM University, Kattankullathur, Chennai, 603203, Tamil Nadu (India); Durgadevi, E. [Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka, 432-8011 (Japan); Raji, P. [Department of Physics, Mepco Schlenk Engineering College, Sivakasi, 626 005, Tamil Nadu (India); Ponnusamy, S., E-mail: suruponnus@gmail.com [Department of Physics and Nanotechnology, SRM University, Kattankullathur, Chennai, 603203, Tamil Nadu (India); Muthamizhchelvan, C. [Department of Physics and Nanotechnology, SRM University, Kattankullathur, Chennai, 603203, Tamil Nadu (India); Hayakawa, Y. [Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka, 432-8011 (Japan); Kim, Deuk Young [Department of Semiconductor Science, Dongguk University-Seoul, Jung-gu, Seoul, 04620 (Korea, Republic of)

    2017-05-01

    Nanostructured bismuth titanate (Bi{sub 4}Ti{sub 3}O{sub 12}) or BTO powders were synthesized by the combustion method. The crystalline phase of BTO nanopowders was evaluated from X-ray diffraction (XRD) and further confirmed by selected area electron diffraction (SAED) pattern. The SEM and TEM micrographic images clearly showed the nanosheets like morphology of BTO nanopowder. The EDS spectrum of BTO nanopowder showed the elemental peaks of O, Bi and Ti at 0.53 keV, 2.41 keV and 4.49 keV, respectively. FTIR band peaks were observed at 815 and 595 cm{sup -1} corresponding to the stretching vibrations of Bi-O and Ti-O. The red shift in optical absorption of BTO was observed and the bandgap decreased from 3.18 to 3.08 eV as the calcined temperature increased from 600 to 800 °C. The sandwich structure, called the nanogenerator, Graphene/BTO-PDMS/Graphene (G/BTO/G), was fabricated on graphene coated polymethyl methacrylate (PMMA) substrates, which produced a peak voltage (10 mV) by applying the pressure from human's finger. The switching mechanism of BTO nanosheets was observed to be dependent on the polarity and intrinsic dipole formation. - Highlights: • Bi{sub 4}Ti{sub 3}O{sub 12} (BTO) nanosheets synthesized from a simple combustion method. • SEM & TEM images confirmed the nanosheets structure with a hexagonal shape. • XRD and SAED pattern of BTO nanosheets confirmed the orthorhombic crystal structure. • Flexible G/BTO/G nanogenerator fabricated by sol-gel method. • Peak voltage was observed to be 10 mV by applying pressure from human's finger.

  18. Preparing of Highly Conductive Patterns on Flexible Substrates by Screen Printing of Silver Nanoparticles with Different Size Distribution.

    Science.gov (United States)

    Ding, Jin; Liu, Jun; Tian, Qingyong; Wu, Zhaohui; Yao, Weijing; Dai, Zhigao; Liu, Li; Wu, Wei

    2016-12-01

    A facile one-step polyol method is employed to synthesize the Ag nanoparticles (NPs) in large scale. The Ag NPs with different average diameter (from 52 to 120 nm) and particle size distribution are prepared by changing the mass ratio of AgNO3 and PVP. Furthermore, the as-obtained Ag NPs are prepared as conductive inks, which could be screen printed on various flexible substrates and formed as conductive patterns after sintering treatment. During the reaction process, PVP is used as the capping reagent for preventing the agglomeration of Ag NPs, and the influence of the mass ratio of AgNO3 and PVP to the size distribution of Ag NPs is investigated. The results of electronic properties reveal that the conductivity of printed patterns is highly dependent on the size distribution of as-obtained Ag NPs. Among all the samples, the optimal conductivity is obtained when the mass ratio of AgNO3 and PVP is 1:0.4. Subsequently, the sintering time and temperature are further investigated for obtaining the best conductivity; the optimal electrical resistivity value of 3.83 μΩ · cm is achieved at 160 °C for 75 min, which is close to the resistivity value of the bulk silver (1.58 μΩ · cm). Significantly, there are many potential advantages in printed electronics applications because of the as-synthesized Ag NPs with a low sintering temperature and low electrical resistivity.

  19. Large-scale synthesis of flexible free-standing SERS substrates with high sensitivity: electrospun PVA nanofibers embedded with controlled alignment of silver nanoparticles.

    Science.gov (United States)

    He, Dian; Hu, Bo; Yao, Qiao-Feng; Wang, Kan; Yu, Shu-Hong

    2009-12-22

    A new and facile way to synthesize a free-standing and flexible surface-enhanced Raman scattering (SERS) substrate has been successfully developed, where high SERS-active Ag dimers or aligned aggregates are assembled within poly(vinyl alcohol) (PVA) nanofibers with chain-like arrays via electrospinning technique. The aggregation state of the obtained Ag nanoparticle dimers or larger, which are formed in a concentrated PVA solution, makes a significant contribution to the high sensitivity of SERS to 4-mercaptobenzoic acid (4-MBA) molecules with an enhancement factor (EF) of 10(9). The superiority of enhancement ability of this Ag/PVA nanofiber mat is also shown in the comparison to other substrates. Furthermore, the Ag/PVA nanofiber mat would keep a good reproducibility under a low concentration of 4-MBA molecule (10(-6) M) detection with the average RSD values of the major Raman peak less than 0.07. The temporal stability of the substrate has also been demonstrated. This disposable, easy handled, flexible free-standing substrate integrated the advantages including the superiority of high sensitivity, reproducibility, stability, large-scale, and low-cost production compared with other conventional SERS substrates, implying that it is a perfect choice for practical SERS detection application.

  20. 柔性基板弯曲度对信号质量影响分析%Analysis of Signal Quality on Folded Flexible Substrate

    Institute of Scientific and Technical Information of China (English)

    陶文君; 万里兮

    2012-01-01

    Flexible substrate has mechanical flexibility to realize high density interconnection, and is now widely used in packaging structures. The signal integrity ( SI) problems and electromagnetic interference ( EMI) caused by the mechanical bending of flexible substrate restricted its use to a large extent. To settle this problem, 3D simulation analysis is adopted to compare SI characteristics and EMI of flexible substrates with different bending radiuses both in frequency and time domains. The simulation results show that when bending radius doubles, insertion loss would reduce by 0. 9 dB, return loss would reduce by 2 dB, electric field radiation would become weaker, and the rise time of eye diagram would display smaller degradation. In other words, the bending radius of flexible substrate is bigger, the transmission performance of signal is better. The result provides the theory basis for the use of flexible substrates in 3D high speed and high density packages.%柔性基板具有机械柔韧性和高密度互连的特点,现采用柔性基板来实现封装结构的也越来越多.柔性基板由于其机械弯曲引起的信号完整性问题和电磁干扰问题是柔性基板应用于高速高密电子封装的重要制约因素.针对该问题,应用三维仿真分析方法,分别从频域和时域研究了柔性基板在不同弯曲半径下的信号完整性与电磁干扰性的问题.仿真结果显示,弯曲半径增加一倍,插入损耗减小约0.9 dB,回波损耗减小约2 dB,电场辐射越弱,眼图的上升时间退化越小;即柔性基板弯曲半径越大,高速信号的传输质量越好.该结果为使用柔性基板实现三维高速高密封装提供理论依据.

  1. Printable Silicon Nanomembranes for Solar-Powered, Bi-Directional Phased-Array-Antenna Communication System on Flexible Substrates

    Science.gov (United States)

    2013-04-01

    Identification (RFID), Large Area Flexible Displays, Electronic Paper, Bio-Sensors, Large Area Conformal and Flexible Antennas, Smart and Interactive Textiles ... market . 4. ACCOMPLISHMENTS/NEW FINDINGS Through this Phase II program, we have achieved several important milestones that can form the basis for future...displays [58], flexible silicon integrated circuits [59], photonic crystal filters [60, 61], smart skins [62], etc. Among all the transferable

  2. Effects of Substrate Temperature on Structural and Optical Properties of Spray-Pyrolyzed Cu(Ga0.3In0.7)Se2 Thin Films on Polyimide Plastic Substrate

    Science.gov (United States)

    Faraj, M. G.; Pakhuruddin, M. Z.; Taboada, P.

    2017-08-01

    Chalcopyrite copper indium gallium diselenide Cu(Ga0.3In0.7)Se2 films have been deposited on polyimide (PI) plastic substrate by chemical spray pyrolysis using different substrate temperatures in the range from 350°C to 395°C. The influence of substrate temperature on the structural and optical properties of the CIGS films was studied. High-resolution x-ray diffraction results revealed that the films exhibited chalcopyrite-type structure. The crystallite size of the films increased with increasing substrate temperature, as did their root-mean-square surface roughness. Optical transmission measurements by ultraviolet-visible (UV-Vis) spectrophotometer showed that the optical bandgap decreased from 1.28 eV to 1.16 eV as the substrate temperature was increased. This variation of the crystallite size and energy bandgap with substrate temperature makes such films a promising candidate for application in optoelectronic devices such as photoconductors and solar cells.

  3. The role of the spray pyrolysed Al2O3 barrier layer in achieving high efficiency solar cells on flexible steel substrates

    Science.gov (United States)

    Gledhill, Sophie E.; Zykov, Anton; Rissom, Thorsten; Caballero, Raquel; Kaufmann, Christian A.; Fischer, Christian-Herbert; Lux-Steiner, Martha; Efimova, Varvara; Hoffmann, Volker; Oswald, Steffen

    2011-07-01

    Thin film chalcopyrite solar cells grown on light-weight, flexible steel substrates are poised to enter the photovoltaic market. To guarantee good solar cell performance, the diffusion of iron from the steel into the CIGSe absorber material must be hindered during layer deposition. A barrier layer is thus required to isolate the solar module from the metal substrate, both electronically and chemically. Ideally the barrier layer would be deposited by a cheap roll-to-roll process suitable to coat flexible steel substrates. Aluminium oxide deposited by spray pyrolysis matches the criteria. The coating is homogeneous over rough substrates allowing comparatively thin barrier layers to be utilized. In this article, solar cell results are presented contrasting the device performance made with a barrier layer to that without a barrier layer. Secondary Ion Mass spectrometry (SIMS) measurements show that the spray pyrolysed barrier layer diminishes iron diffusion to the chalcopyrite absorber layer. The role of sodium, imperative for the growth of high efficiency chalcopyrite solar cells, and how it interacts with Al2O3 is discussed.

  4. Experimental and first-principles study of the electronic transport properties of strained Bi2Te3 thin films on a flexible substrate

    Science.gov (United States)

    Inamoto, Takuya; Takashiri, Masayuki

    2016-09-01

    On the basis of an experimental and first-principles study, strain effects on the thermoelectric properties of bismuth telluride (Bi2Te3) thin films were investigated. Bi2Te3 thin films were deposited on flexible polyimide substrates using a radio frequency magnetron sputtering method at a substrate temperature of 200 °C. Prior to deposition, various compressive and tensile bending strains were applied to the films by changing the bending radii of the flexible substrates. The structural and thermoelectric properties of the completed samples were analyzed. It was found that the lattice parameters of all samples exhibited smaller values compared to that of standard data for Bi2Te3 (JCPDS 15-0863) because the substrates might have shrunk during the film deposition, indicated by the fact that all the samples presented various compressive lattice strains. A theoretical analysis was performed using the first-principles study based on density functional theory. We calculated the electronic band structures for Bi2Te3 with the different lattice strains and predicted the thermoelectric properties based on the semi-classical Boltzmann transport equation in the rigid band approximation. The lowest conduction band edge in the Bi2Te3 band structure narrowed as the compressive lattice strain increased, indicating that the effective mass became smaller. Finally, the experimentally measured thermoelectric properties were compared with those obtained by the calculation. It was found that the calculated results were in good agreement with the experimental results.

  5. Printing Technologies and Environmentally-friendly Measures of Plastic Flexible Packaging Film%塑料软包装薄膜的印刷技术及环保措施

    Institute of Scientific and Technical Information of China (English)

    庄树贵; 龚伟兵

    2011-01-01

    The printing and compounding technologies of plastic flexible packaging film were introduced.The environmentally-friendly measures in plastic flexible packaging film were expounded from the aspects of printing ink, raw material, waste material treatment, etc. The development direction of the plastic flexible packaging film was also predicted.%介绍了塑料软包装薄膜的印刷和复合工艺,从油墨、塑料原料及废弃物处理等方面阐述了塑料软包装薄膜印刷工业中采取的环保措施,并指出了塑料软包装薄质印刷工业的发展方向.

  6. Phenotypic plasticity in the common garden snail: big guts and heavier mucus glands compete in snails faced with the dual challenge of poor diet and coarse substrate.

    Science.gov (United States)

    Munn, Adam J; Treloar, Marguerite

    2016-12-26

    Phenotypic plasticity allows animals to manage environmental challenges. Studies aimed at quantifying plasticity often focus on one challenge, such as diet, and one organ system, such the gastrointestinal tract, but this approach may not adequately reflect how plasticity could buffer multiple challenges. Thus, we investigated the outcomes of a dual challenge experiment that fed land snails either a high-fibre (low quality) or a low-fibre (high quality) diet, and simultaneously exercised them daily over 1.2 m on either a smooth surface of polyvinyl chloride (PVC) or a rough sandpaper. By the end of 20 days, snails fed the poor quality diet had a longer crop and oesophagus and a heavier intestine and rectum than those offered a low-fibre diet. Additionally, high-fibre fed snails had a smaller spermoviduct and oviduct. When also exercised on sandpaper, high-fibre fed snails had a smaller digestive gland, a main energy store, than those exercised on PVC. All snails exercised on sandpaper had a heavier pedal mucus gland, used a loping gait and used less mucus than those on PVC plastic, but there was no difference in the average speed of snails on either surface, supporting the conclusion that loping is a mucus conserving gait. Notably, snails faced with both a diet and substrate challenge had a smaller kidney, which could directly effect fecundity. This demonstrates that our dual challenge approach has potential for evaluating the costs and limits of the plasticity necessary to fully appreciate the evolutionary significance of plasticity in snails and other species.

  7. Numerical modelling of sliding wear caused by pin-on-disk method over copper coated ABS plastic substrate

    Science.gov (United States)

    Nigam, S.; Mahapatra, S. S.; Patel, S. K.

    2016-09-01

    The coating of metal increases the face value of the plastic and inhibits other properties like conductivity, hardness and lustre. Thus the combination of plastic and metal coating results in a material that is light in weight because of the presence of plastic as the base material and; electrical and thermal conductive because of the presence of metal on the surface. The requirement of such materials is growing day by day. Copper coated plastic has various applications such as in fabrication of printed circuit boards (PCB's) and various automobile parts and in electromagnetic interference shielding. It is important to analyse the tribological aspect of the same in order to broaden its range of application. The present work contains 3D modelling of thermally sprayed copper on ABS plastic and simulation of sliding wear test by pin-on-disc method. The Johnson cook flow stress model is selected for the coating material. Archard's wear model has provided the best results for calculating the wear rate. The results obtained are in good agreement with the experimental values.

  8. Investigation of the interfacial adhesion of the transparent conductive oxide films to large-area flexible polymer substrates using laser-induced thermo-mechanical stresses

    Science.gov (United States)

    Park, Jin-Woo; Lee, Seung-Ho; Yang, Chan-Woo

    2013-08-01

    In this study, we investigated the interfacial adhesion strength (σint) of transparent conductive oxide (TCO) coatings on polymer substrates using a nanosecond Nd:YAG pulsed laser. We compared our results with those achieved using conventional testing methods such as bending and fragmentation tests as well as theoretical calculations. In the fragmentation and bending tests, mechanical compressive stress is induced in the film due to mismatches in Poisson's ratio and Young's modulus between the substrate and film. But, the incident laser makes the film under compression due to the mismatch in thermal expansion between the TCO and the polymer substrate. With a pulse incident to the substrate, the TCO rapidly expands by laser-induced instant heating while the transparent polymer does little, which causes the TCO to buckle and delaminate over the critical pulse energy. The critical compressive stress that scales with σint was calculated using simple equations, which agreed well with the results from previous theoretical calculations. Because the films preferentially delaminate at the defects and grain boundaries, this technique also provided useful information regarding the interface microstructures. Moreover, because the laser can scan over large areas, this method is suitable for flexible substrates that are produced by a roll-to-roll process. Nevertheless, the mechanical stress introduced by the bending and fragmentation tests causes the TCO to buckle without interfacial delamination. Hence, the stresses at the buckling disagreed with the results obtained from the laser test and the theoretical calculations.

  9. Highly Uniform Thin-Film Transistors Printed on Flexible Plastic Films with Morphology-Controlled Carbon Nanotube Network Channels

    Science.gov (United States)

    Numata, Hideaki; Ihara, Kazuki; Saito, Takeshi; Endoh, Hiroyuki; Nihey, Fumiyuki

    2012-05-01

    Carbon nanotube (CNT) transistor arrays were fabricated on plastic films by printing. All the device elements were directly patterned by maskless printing without any additional patterning process, and minimum materials were used. During fabrication, the morphology of the CNT random network was controlled by an adsorption mechanism on the surface to be printed, which resulted in excellent and uniform electrical properties. The field-effect mobility was further improved by post-treatment to modify the morphology of the CNT network. These results are promising for realizing printed electronics integrated with CNT transistors.

  10. Strain-effect transistors: Theoretical study on the effects of external strain on III-nitride high-electron-mobility transistors on flexible substrates

    Science.gov (United States)

    Shervin, Shahab; Kim, Seung-Hwan; Asadirad, Mojtaba; Ravipati, Srikanth; Lee, Keon-Hwa; Bulashevich, Kirill; Ryou, Jae-Hyun

    2015-11-01

    This paper presents strain-effect transistors (SETs) based on flexible III-nitride high-electron-mobility transistors (HEMTs) through theoretical calculations. We show that the electronic band structures of InAlGaN/GaN thin-film heterostructures on flexible substrates can be modified by external bending with a high degree of freedom using polarization properties of the polar semiconductor materials. Transfer characteristics of the HEMT devices, including threshold voltage and transconductance, are controlled by varied external strain. Equilibrium 2-dimensional electron gas (2DEG) is enhanced with applied tensile strain by bending the flexible structure with the concave-side down (bend-down condition). 2DEG density is reduced and eventually depleted with increasing compressive strain in bend-up conditions. The operation mode of different HEMT structures changes from depletion- to enchantment-mode or vice versa depending on the type and magnitude of external strain. The results suggest that the operation modes and transfer characteristics of HEMTs can be engineered with an optimum external bending strain applied in the device structure, which is expected to be beneficial for both radio frequency and switching applications. In addition, we show that drain currents of transistors based on flexible InAlGaN/GaN can be modulated only by external strain without applying electric field in the gate. The channel conductivity modulation that is obtained by only external strain proposes an extended functional device, gate-free SETs, which can be used in electro-mechanical applications.

  11. Strain-effect transistors: Theoretical study on the effects of external strain on III-nitride high-electron-mobility transistors on flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Shervin, Shahab; Asadirad, Mojtaba [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204-4006 (United States); Materials Science and Engineering Program, University of Houston, Houston, Texas 77204 (United States); Kim, Seung-Hwan; Ravipati, Srikanth; Lee, Keon-Hwa [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204-4006 (United States); Bulashevich, Kirill [STR Group, Inc., Engels av. 27, P.O. Box 89, 194156, St. Petersburg (Russian Federation); Ryou, Jae-Hyun, E-mail: jryou@uh.edu [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204-4006 (United States); Materials Science and Engineering Program, University of Houston, Houston, Texas 77204 (United States); Texas Center for Superconductivity at the University of Houston (TcSUH), University of Houston, Houston, Texas 77204 (United States)

    2015-11-09

    This paper presents strain-effect transistors (SETs) based on flexible III-nitride high-electron-mobility transistors (HEMTs) through theoretical calculations. We show that the electronic band structures of InAlGaN/GaN thin-film heterostructures on flexible substrates can be modified by external bending with a high degree of freedom using polarization properties of the polar semiconductor materials. Transfer characteristics of the HEMT devices, including threshold voltage and transconductance, are controlled by varied external strain. Equilibrium 2-dimensional electron gas (2DEG) is enhanced with applied tensile strain by bending the flexible structure with the concave-side down (bend-down condition). 2DEG density is reduced and eventually depleted with increasing compressive strain in bend-up conditions. The operation mode of different HEMT structures changes from depletion- to enchantment-mode or vice versa depending on the type and magnitude of external strain. The results suggest that the operation modes and transfer characteristics of HEMTs can be engineered with an optimum external bending strain applied in the device structure, which is expected to be beneficial for both radio frequency and switching applications. In addition, we show that drain currents of transistors based on flexible InAlGaN/GaN can be modulated only by external strain without applying electric field in the gate. The channel conductivity modulation that is obtained by only external strain proposes an extended functional device, gate-free SETs, which can be used in electro-mechanical applications.

  12. High quality transparent TiO2/Ag/TiO2 composite electrode films deposited on flexible substrate at room temperature by sputtering

    OpenAIRE

    Aritra Dhar; Alford, T. L.

    2013-01-01

    Multilayer structures of TiO2/Ag/TiO2 have been deposited onto flexible substrates by room temperature sputtering to develop indium-free transparent composite electrodes. The effect of Ag thicknesses on optical and electrical properties and the mechanism of conduction have been discussed. The critical thickness (tc) of Ag mid-layer to form a continuous conducting layer is 9.5 nm and the multilayer has been optimized to obtain a sheet resistance of 5.7 Ω/sq and an average optical transmittance...

  13. A laboratory scale approach to polymer solar cells using one coating/printing machine, flexible substrates, no ITO, no vacuum and no spincoating

    DEFF Research Database (Denmark)

    Carlé, Jon Eggert; Andersen, Thomas Rieks; Helgesen, Martin

    2013-01-01

    Printing of the silver back electrode under ambient conditions using simple laboratory equipment has been the missing link to fully replace evaporated metal electrodes. Here we demonstrate how a recently developed roll coater is further developed into a single machine that enables processing of all...... layers of the polymer solar cell without moving the substrate from one machine to another. The novel approach to polymer solar cells is readily scalable using one compact laboratory scale coating/printing machine that is directly compatible with industrial and pilot scale roll-to-roll processing. The use...... of the techniques was successfully demonstrated in one continuous roll process on flexible polyethyleneterphthalate (PET) substrates and polymer solar cells were prepared by solution processing of five layers using only slot-die coating and flexographic printing. The devices obtained did not employ indium...

  14. Effect of maleic anhydride-aniline derivative buffer layer on the properties of flexible substrate heterostructures: Indium tin oxide/nucleic acid base/metal

    Energy Technology Data Exchange (ETDEWEB)

    Stanculescu, A., E-mail: sanca@infim.ro [National Institute of Materials Physics, 105 bis Atomistilor Street, P.O. Box MG-7, 077125, Bucharest-Magurele (Romania); Socol, M. [National Institute of Materials Physics, 105 bis Atomistilor Street, P.O. Box MG-7, 077125, Bucharest-Magurele (Romania); Socol, G.; Mihailescu, I.N. [National Institute for Laser, Plasma and Radiation Physics, P.O. Box MG-36, 077125, Bucharest-Magurele (Romania); Girtan, M. [Laboratoire de Photonique d' Angers, Universite d' Angers, 2, Bd. Lavoisier, 49045, Angers (France); Preda, N. [National Institute of Materials Physics, 105 bis Atomistilor Street, P.O. Box MG-7, 077125, Bucharest-Magurele (Romania); Albu, A.-M. [Department of Polymer Science, University ' Politehnica' of Bucharest, Bucharest (Romania); Stanculescu, F. [University of Bucharest, Faculty of Physics, Str. Atomistilor nr.405, P.O. Box MG-11, Bucharest-Magurele, 077125 (Romania)

    2011-12-01

    This paper presents some investigations on the properties of guanine (G) and cytosine (C) based heterostructures deposited on flexible substrates. The effects of two types of maleic anhydride-aniline derivatives (maleic anhydride-cyano aniline or maleic anhydride-2,4 dinitroaniline) buffer layer, deposited between indium tin oxide and (G) or (C) layer, on the optical and electrical properties of the heterostructures have been identified. The heterostructures containing a film of maleic anhydride-2,4 dinitroaniline have shown a good transparency and low photoluminescence in visible range. This buffer layer has determined an increase in the conductance only in the heterostructures based on (G) and (C) deposited on biaxially-oriented polyethylene terephthalate substrate.

  15. Fabrication of transistors on flexible substrates: from mass-printing to high-resolution alternative lithography strategies

    NARCIS (Netherlands)

    Moonen, P.; Yakimets, I.; Huskens, J.

    2012-01-01

    In this report, the development of conventional, mass-printing strategies into high-resolution, alternative patterning techniques is reviewed with the focus on large-area patterning of flexible thin-film transistors (TFTs) for display applications. In the first part, conventional and digital printin

  16. Investigation of the Structural, Electrical, and Optical Properties of the Nano-Scale GZO Thin Films on Glass and Flexible Polyimide Substrates

    Directory of Open Access Journals (Sweden)

    Fang-Hsing Wang

    2016-05-01

    Full Text Available In this study, Ga2O3-doped ZnO (GZO thin films were deposited on glass and flexible polyimide (PI substrates at room temperature (300 K, 373 K, and 473 K by the radio frequency (RF magnetron sputtering method. After finding the deposition rate, all the GZO thin films with a nano-scale thickness of about 150 ± 10 nm were controlled by the deposition time. X-ray diffraction patterns indicated that the GZO thin films were not amorphous and all exhibited the (002 peak, and field emission scanning electron microscopy showed that only nano-scale particles were observed. The dependences of the structural, electrical, and optical properties of the GZO thin films on different deposition temperatures and substrates were investigated. X-ray photoemission spectroscopy (XPS was used to measure the elemental composition at the chemical and electronic states of the GZO thin films deposited on different substrates, which could be used to clarify the mechanism of difference in electrical properties of the GZO thin films. In this study, the XPS binding energy spectra of Ga2p3/2 and Ga2p1/2 peaks, Zn2p3/2 and Zn2p1/2 peaks, the Ga3d peak, and O1s peaks for GZO thin films on glass and PI substrates were well compared.

  17. Nanostructured SERS substrates produced by nanosphere lithography and plastic deformation through direct peel-off on soft matter

    Science.gov (United States)

    Wang, Tzyy-Jiann; Hsu, Kai-Chieh; Liu, Yi-Cheng; Lai, Chih-Hsien; Chiang, Hai-Pang

    2016-05-01

    We present a novel fragmented-film surface-enhanced Raman scattering (SERS) substrate produced by nanosphere lithography and direct peel-off for SERS efficacy enhancement. The 2D hexagonally close-packed polystyrene nanospheres on the polydimethylsilozane (PDMS) substrate are covered with silver film and then directly peeled off using sticky tape. During the peel-off process, the pulling force induces the stretch and contraction of the PDMS substrate and causes fracture of the 2D triangular silver film. Under laser excitation, a stronger localized electric field is induced in the smaller cracks and enhances the SERS intensity. The origin of this SERS enhancement is confirmed by numerical simulation using the finite element method and substrate annealing to smoothen the cracks. For the case using nanospheres with a diameter of 740 nm, an enhancement factor 6.5 × 106 can be achieved. The proposed fragmented-film SERS substrate gains 1.8 and 2.6 times larger Raman intensity at the 1358 cm-1 SERS peak than those using pyramidal silver islands and silver nanoshell array. The proposed SERS substrate has the features of easy fabrication, low production cost, short fabrication time and high enhancement factor.

  18. Fast Flexible Transistors with a Nanotrench Structure

    Science.gov (United States)

    Seo, Jung-Hun; Ling, Tao; Gong, Shaoqin; Zhou, Weidong; Ma, Alice L.; Guo, L. Jay; Ma, Zhenqiang

    2016-04-01

    The simplification of fabrication processes that can define very fine patterns for large-area flexible radio-frequency (RF) applications is very desirable because it is generally very challenging to realize submicron scale patterns on flexible substrates. Conventional nanoscale patterning methods, such as e-beam lithography, cannot be easily applied to such applications. On the other hand, recent advances in nanoimprinting lithography (NIL) may enable the fabrication of large-area nanoelectronics, especially flexible RF electronics with finely defined patterns, thereby significantly broadening RF applications. Here we report a generic strategy for fabricating high-performance flexible Si nanomembrane (NM)-based RF thin-film transistors (TFTs), capable of over 100 GHz operation in theory, with NIL patterned deep-submicron-scale channel lengths. A unique 3-dimensional etched-trench-channel configuration was used to allow for TFT fabrication compatible with flexible substrates. Optimal device parameters were obtained through device simulation to understand the underlying device physics and to enhance device controllability. Experimentally, a record-breaking 38 GHz maximum oscillation frequency fmax value has been successfully demonstrated from TFTs with a 2 μm gate length built with flexible Si NM on plastic substrates.

  19. Fast Flexible Transistors with a Nanotrench Structure.

    Science.gov (United States)

    Seo, Jung-Hun; Ling, Tao; Gong, Shaoqin; Zhou, Weidong; Ma, Alice L; Guo, L Jay; Ma, Zhenqiang

    2016-04-20

    The simplification of fabrication processes that can define very fine patterns for large-area flexible radio-frequency (RF) applications is very desirable because it is generally very challenging to realize submicron scale patterns on flexible substrates. Conventional nanoscale patterning methods, such as e-beam lithography, cannot be easily applied to such applications. On the other hand, recent advances in nanoimprinting lithography (NIL) may enable the fabrication of large-area nanoelectronics, especially flexible RF electronics with finely defined patterns, thereby significantly broadening RF applications. Here we report a generic strategy for fabricating high-performance flexible Si nanomembrane (NM)-based RF thin-film transistors (TFTs), capable of over 100 GHz operation in theory, with NIL patterned deep-submicron-scale channel lengths. A unique 3-dimensional etched-trench-channel configuration was used to allow for TFT fabrication compatible with flexible substrates. Optimal device parameters were obtained through device simulation to understand the underlying device physics and to enhance device controllability. Experimentally, a record-breaking 38 GHz maximum oscillation frequency fmax value has been successfully demonstrated from TFTs with a 2 μm gate length built with flexible Si NM on plastic substrates.

  20. Robotic Deposition of TiO2 Films on Flexible Substrates from Hybrid Inks: Investigation of Synthesis-Processing-Microstructure-Photocatalytic Relationships.

    Science.gov (United States)

    Torres Arango, Maria A; Valença de Andrade, Alana S; Cipollone, Domenic T; Grant, Lynnora O; Korakakis, Dimitris; Sierros, Konstantinos A

    2016-09-21

    TiO2 is an important material widely used in optoelectronic devices due to its semiconducting and photocatalytic properties, nontoxicity, and chemically inert nature. Some indicative applications include water purification systems and energy harvesting. The use of solution, water-based inks for the direct writing of TiO2 on flexible substrates is of paramount importance since it enables low-cost and low-energy intensive large-area manufacturing, compatible with roll-to-roll processing. In this work we study the effect of crystalline TiO2 and polymer addition on the rheological and direct writing properties of Ti-organic/TiO2 inks. We also report on the bridging crystallite formation from the Ti-organic precursor into the TiO2 crystalline phase, under ultraviolet (UV) exposure or mild heat treatments up to 150 °C. Such crystallite formation is found to be enhanced by polymers with strong polarity and pKα such as polyacrylic acid (PAA). X-ray diffraction (XRD) coupled with Raman and X-ray photoelectron (XPS) spectroscopy are used to investigate the crystalline-phase transformation dependence based on the initial TiO2 crystalline-phase concentration and polymer addition. Transmission electron microscopy imaging and selected area electron diffraction patterns confirm the crystalline nature of such bridging printed structures. The obtained inks are patterned on flexible substrates using nozzle-based robotic deposition, a lithography-free, additive manufacturing technique that allows the direct writing of material in specific, digitally predefined, substrate locations. Photocatalytic degradation of methylene blue solutions highlights the potential of the studied films for chemical degradation applications, from low-cost environmentally friendly materials systems.

  1. Ceramic barrier layers for flexible thin film solar cells on metallic substrates: a laboratory scale study for process optimization and barrier layer properties.

    Science.gov (United States)

    Delgado-Sanchez, Jose-Maria; Guilera, Nuria; Francesch, Laia; Alba, Maria D; Lopez, Laura; Sanchez, Emilio

    2014-11-12

    Flexible thin film solar cells are an alternative to both utility-scale and building integrated photovoltaic installations. The fabrication of these devices over electrically conducting low-cost foils requires the deposition of dielectric barrier layers to flatten the substrate surface, provide electrical isolation between the substrate and the device, and avoid the diffusion of metal impurities during the relatively high temperatures required to deposit the rest of the solar cell device layers. The typical roughness of low-cost stainless-steel foils is in the hundred-nanometer range, which is comparable or larger than the thin film layers comprising the device and this may result in electrical shunts that decrease solar cell performance. This manuscript assesses the properties of different single-layer and bilayer structures containing ceramics inks formulations based on Al2O3, AlN, or Si3N4 nanoparticles and deposited over stainless-steel foils using a rotogravure printing process. The best control of the substrate roughness was achieved for bilayers of Al2O3 or AlN with mixed particle size, which reduced the roughness and prevented the diffusion of metals impurities but AlN bilayers exhibited as well the best electrical insulation properties.

  2. Realization of dual-heterojunction solar cells on ultra-thin ∼25 μm, flexible silicon substrates

    KAUST Repository

    Onyegam, Emmanuel U.

    2014-04-14

    Silicon heterojunction (HJ) solar cells with different rear passivation and contact designs were fabricated on ∼ 25 μ m semiconductor-on-metal (SOM) exfoliated substrates. It was found that the performance of these cells is limited by recombination at the rear-surface. Employing the dual-HJ architecture resulted in the improvement of open-circuit voltage (Voc) from 605 mV (single-HJ) to 645 mV with no front side intrinsic amorphous silicon (i-layer) passivation. Addition of un-optimized front side i-layer passivation resulted in further enhancement in Voc to 662 mV. Pathways to achieving further improvement in the performance of HJ solar cells on ultra-thin SOM substrates are discussed. © 2014 AIP Publishing LLC.

  3. Développement de conducteurs à base d'YBaCuO
    sur des substrats flexibles par MOCVD

    OpenAIRE

    CAROFF, Tristan

    2008-01-01

    The stake of this study was to realize low cost superconducting wires for current transport and current limitation, using original and inexpensive processes like rolling for the elaboration of the substrate, and chemical deposition methods MOD (metal organic decomposition) and MOCVD (metal organic chemical vapor deposition) for the different layers (buffer layers and superconducting film).Pulsed injection MOCVD technique is well adapted for coated conductor processing: it allows obtaining rep...

  4. Controlled assemblies of gold nanorods in PVA nanofiber matrix as flexible free-standing SERS substrates by electrospinning.

    Science.gov (United States)

    Zhang, Chuan-Ling; Lv, Kong-Peng; Cong, Huai-Ping; Yu, Shu-Hong

    2012-03-12

    Under control: Controlled assemblies of gold nanorods in a poly(vinyl alcohol) (PVA) nanofiber matrix with tunable optical properties can be achieved by using electrospinning. The resultant assemblies can be used as substrates for surface-enhanced Raman spectroscopy (SERS). This work provides a facile way to control alignment of anisotropic nanostructures in a polymer nanofiber matrix and generates new assemblies with interesting properties.

  5. Properties of transparent and conductive Al:ZnO/Au/Al:ZnO multilayers on flexible PET substrates

    Energy Technology Data Exchange (ETDEWEB)

    Dimopoulos, T., E-mail: theodoros.dimopoulos@ait.ac.at [AIT-Austrian Institute of Technology, Energy Department, Photovoltaic Systems, Giefinggasse 2, 1210, Vienna (Austria); Bauch, M.; Wibowo, R.A.; Bansal, N. [AIT-Austrian Institute of Technology, Energy Department, Photovoltaic Systems, Giefinggasse 2, 1210, Vienna (Austria); Hamid, R. [AIT-Austrian Institute of Technology, Mobility Department, Electric Drive Technologies, Giefinggasse 2, 1210, Vienna (Austria); Auer, M.; Jäger, M. [NanoTecCenter Weiz Forschungsgesellschaft mbH, Franz-Pichler Straße 32, A-8160 Weiz (Austria); List-Kratochvil, E.J.W. [NanoTecCenter Weiz Forschungsgesellschaft mbH, Franz-Pichler Straße 32, A-8160 Weiz (Austria); Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz (Austria)

    2015-10-15

    Highlights: • Transparent, low resistive AZO/Au/AZO layers were sputtered on PET substrates. • AZO/Au/AZO has higher figure of merit than ITO for specific Au thicknesses. • The resistance of AZO/Au/AZO is stable against repetitive substrate bending. • AZO/Au/AZO electrode performance is comparable to ITO in light emitting diodes. - Abstract: We investigate the structural, electrical and optical properties of transparent electrodes, consisting of Al-doped ZnO (AZO) and ultrathin Au layers, sputtered on polyethylene terephthalate (PET). These electrodes are relevant for optoelectronic devices and thin film photovoltaics. When deposited on AZO, Au films as thin as 3 nm form electrically conductive, meandering structures, whereas uniform Au films are obtained from a thickness of 5 nm. The sheet resistance decreases with Au thickness, reaching 7 Ω for 11 nm-thick Au. AZO/Au/AZO trilayers combine lowest resistance with highest transparency, while their resistance stability against bending fatigue is superior to the Sn-doped In{sub 2}O{sub 3} (ITO) electrode. The figure of merit of AZO/Au/AZO is larger than of ITO for Au thickness equal to or larger than 9 nm. To demonstrate the applicability of the AZO/Au/AZO transparent electrode, simple organic light emitting diodes were fabricated and tested in comparison to PET/ITO standard substrates.

  6. Metal Decoration Effects on the Gas-Sensing Properties of 2D Hybrid-Structures on Flexible Substrates

    Directory of Open Access Journals (Sweden)

    Byungjin Cho

    2015-09-01

    Full Text Available We have investigated the effects of metal decoration on the gas-sensing properties of a device with two-dimensional (2D molybdenum disulfide (MoS2 flake channels and graphene electrodes. The 2D hybrid-structure device sensitively detected NO2 gas molecules (>1.2 ppm as well as NH3 (>10 ppm. Metal nanoparticles (NPs could tune the electronic properties of the 2D graphene/MoS2 device, increasing sensitivity to a specific gas molecule. For instance, palladium NPs accumulate hole carriers of graphene/MoS2, electronically sensitizing NH3 gas molecules. Contrarily, aluminum NPs deplete hole carriers, enhancing NO2 sensitivity. The synergistic combination of metal NPs and 2D hybrid layers could be also applied to a flexible gas sensor. There was no serious degradation in the sensing performance of metal-decorated MoS2 flexible devices before/after 5000 bending cycles. Thus, highly sensitive and endurable gas sensor could be achieved through the metal-decorated 2D hybrid-structure, offering a useful route to wearable electronic sensing platforms.

  7. Metal Decoration Effects on the Gas-Sensing Properties of 2D Hybrid-Structures on Flexible Substrates.

    Science.gov (United States)

    Cho, Byungjin; Yoon, Jongwon; Lim, Sung Kwan; Kim, Ah Ra; Choi, Sun-Young; Kim, Dong-Ho; Lee, Kyu Hwan; Lee, Byoung Hun; Ko, Heung Cho; Hahm, Myung Gwan

    2015-09-25

    We have investigated the effects of metal decoration on the gas-sensing properties of a device with two-dimensional (2D) molybdenum disulfide (MoS₂) flake channels and graphene electrodes. The 2D hybrid-structure device sensitively detected NO₂ gas molecules (>1.2 ppm) as well as NH₃ (>10 ppm). Metal nanoparticles (NPs) could tune the electronic properties of the 2D graphene/MoS₂ device, increasing sensitivity to a specific gas molecule. For instance, palladium NPs accumulate hole carriers of graphene/MoS₂, electronically sensitizing NH₃ gas molecules. Contrarily, aluminum NPs deplete hole carriers, enhancing NO₂ sensitivity. The synergistic combination of metal NPs and 2D hybrid layers could be also applied to a flexible gas sensor. There was no serious degradation in the sensing performance of metal-decorated MoS₂ flexible devices before/after 5000 bending cycles. Thus, highly sensitive and endurable gas sensor could be achieved through the metal-decorated 2D hybrid-structure, offering a useful route to wearable electronic sensing platforms.

  8. Solid-state electric double layer capacitors fabricated with plastic crystal based flexible gel polymer electrolytes: Effective role of electrolyte anions

    Energy Technology Data Exchange (ETDEWEB)

    Suleman, Mohd; Kumar, Yogesh; Hashmi, S.A., E-mail: sahashmi@physics.du.ac.in

    2015-08-01

    Flexible gel polymer electrolyte (GPE) thick films incorporated with solutions of lithium trifluoromethanesulfonate (Li-triflate or LiTf) and lithium bis trifluoromethane-sulfonimide (LiTFSI) in a plastic crystal succinonitrile (SN), entrapped in poly(vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP) have been prepared and characterized. The films have been used as electrolytes in the electrical double layer capacitors (EDLCs). Coconut-shell derived activated carbon with high specific surface area (∼2100 m{sup 2} g{sup −1}) and mixed (micro- and meso-) porosity has been used as EDLC electrodes. The structural, thermal, and electrochemical characterization of the GPEs have been performed using scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), impedance measurements and cyclic voltammetry. The high ionic conductivity (∼10{sup −3} S cm{sup −1} at 25 °C), good electrochemical stability window (>4.0 V) and flexible nature of the free-standing films of GPEs show their competence in the fabrication of EDLCs. The EDLCs have been tested using electrochemical impedance spectroscopy, cyclic voltammetry, and charge–discharge studies. The EDLCs using LiTf based electrolyte have been found to give higher values of specific capacitance, specific energy, power density (240–280 F g{sup −1}, ∼39 Wh kg{sup −1} and ∼19 kW kg{sup −1}, respectively) than the EDLC cell with LiTFSI based gel electrolyte. EDLCs have been found to show stable performance for ∼10{sup 4} charge–discharge cycles. The comparative studies indicate the effective role of electrolyte anions on the capacitive performance of the solid-state EDLCs. - Graphical abstract: Display Omitted - Highlights: • Flexible EDLCs with succinonitrile based gel electrolyte membranes are reported. • Anionic size of salts in gel electrolytes plays important role on capacitive performance. • Li-triflate incorporated gel electrolyte shows better

  9. 3.4-Inch Quarter High Definition Flexible Active Matrix Organic Light Emitting Display with Oxide Thin Film Transistor

    Science.gov (United States)

    Hatano, Kaoru; Chida, Akihiro; Okano, Tatsuya; Sugisawa, Nozomu; Inoue, Tatsunori; Seo, Satoshi; Suzuki, Kunihiko; Oikawa, Yoshiaki; Miyake, Hiroyuki; Koyama, Jun; Yamazaki, Shunpei; Eguchi, Shingo; Katayama, Masahiro; Sakakura, Masayuki

    2011-03-01

    In this paper, we report a 3.4-in. flexible active matrix organic light emitting display (AMOLED) display with remarkably high definition (quarter high definition: QHD) in which oxide thin film transistors (TFTs) are used. We have developed a transfer technology in which a TFT array formed on a glass substrate is separated from the substrate by physical force and then attached to a flexible plastic substrate. Unlike a normal process in which a TFT array is directly fabricated on a thin plastic substrate, our transfer technology permits a high integration of high performance TFTs, such as low-temperature polycrystalline silicon TFTs (LTPS TFTs) and oxide TFTs, on a plastic substrate, because a flat, rigid, and thermally-stable glass substrate can be used in the TFT fabrication process in our transfer technology. As a result, this technology realized an oxide TFT array for an AMOLED on a plastic substrate. Furthermore, in order to achieve a high-definition AMOLED, color filters were incorporated in the TFT array and a white organic light-emitting diode (OLED) was combined. One of the features of this device is that the whole body of the device can be bent freely because a source driver and a gate driver can be integrated on the substrate due to the high mobility of an oxide TFT. This feature means “true” flexibility.

  10. Organic Field-Effect Transistors Based on a Liquid-Crystalline Polymeric Semiconductor using SU-8 Gate Dielectrics onFlexible Substrates

    Directory of Open Access Journals (Sweden)

    Kornelius Tetzner

    2014-10-01

    Full Text Available In this work, the insulating properties of poly(4-vinylphenol (PVP and SU-8 (MicroChem, Westborough, MA, USA dielectrics are analyzed and compared with each other. We further investigate the performance behavior of organic field-effect transistors based on a semiconducting liquid-crystal polymer (LCP using both dielectric materials and evaluate the results regarding the processability. Due to the lower process temperature needed for the SU-8 deposition, the realization of organic transistors on flexible substrates is demonstrated showing comparable charge carrier mobilities to devices using PVP on glass. In addition, a µ-dispensing procedure of the LCP on SU-8 is presented, improving the switching behavior of the organic transistors, and the promising stability data of the SU-8/LCP stack are verified after storing the structures for 60 days in ambient air showing negligible irreversible degradation of the organic semiconductor.

  11. Investigation of the biaxial stress of Al-doped ZnO thin films on a flexible substrate with RF magnetron sputtering

    Science.gov (United States)

    Huang, Kuo-Ting; Chen, Hsi-Chao; Cheng, Po-Wei; Chang, Jhe-Ming

    2016-01-01

    Transparent conductive Al-doped ZnO (AZO) thin films were deposited onto poly(ethylene terephthalate) (PET) substrate, using the radio frequency (RF) magnetron sputtering method. The residual stress of flexible electronics was investigated by a double beam shadow moiré interferometer with phase shifting interferometry (PSI). Moreover, the biaxial stress of AZO thin films can be graphically represented by using Mohr’s circle of stress. The residual stress of AZO thin films becomes more compressive with the increase in sputtering power. The maximum residual stress is -1115.74 MPa, and the shearing stress is 490.57 MPa at a sputtering power of 200 W. The trends of residual stress were evidenced by the X-ray diffraction (XRD) patterns and optical properties of AZO thin films. According to the evaluation results of the refractive index and the extinction coefficient, the AZO thin films have better quality when the sputtering power less than 100 W.

  12. Upscaling from single cells to modules – fabrication of vacuum- and ITO-free polymer solar cells on flexible substrates with long lifetime

    DEFF Research Database (Denmark)

    Carlé, Jon Eggert; Helgesen, Martin; Madsen, Morten Vesterager

    2014-01-01

    modules. We studied from single cells (1 cm2) to modules comprising four serially connected devices with a total active area of 8 cm2. Four different polymers (P3HT, PV-D4610, PDTSTTz-4 and PBDTTTz-4) were applied in the preparation of the modules and efficiencies of more than 3% were achieved which......Fabrication of polymer solar cell (PSC) modules was done on a previously reported compact coating/printing machine and tested in a readily scalable roll process on flexible substrates without applying vacuum, ITO or spin coating. Our aim was to establish loss upon scaling from cells to small...... is comparable to single cell devices prepared using the same process. This proves that it is possible to scale up new materials in an ITO free device context to modules without having an efficiency drop, due to reliable and consistent processing. The main loss observed was due to the packaging using barrier...

  13. Flexible Transparent Electrode of Hybrid Ag-Nanowire/Reduced-Graphene-Oxide Thin Film on PET Substrate Prepared Using H2/Ar Low-Damage Plasma

    Directory of Open Access Journals (Sweden)

    Chi-Hsien Huang

    2017-01-01

    Full Text Available We employ H2/Ar low-damage plasma treatment (H2/Ar-LDPT to reduce graphene oxide (GO coating on a polymer substrate—polyethylene terephthalate (PET—with the assistance of atomic hydrogen (Hα at low temperature of 70 °C. Four-point probing and ultraviolet-visible (UV-Vis spectroscopy demonstrate that the conductivity and transmittance can be controlled by varying the H2/Ar flow rate, treatment time, and radio-frequency (RF power. Optical emission spectroscopy reveals that the Hα intensity depends on these processing parameters, which influence the removal of oxidative functional groups (confirmed via X-ray photoelectron spectroscopy to yield reduced GO (rGO. To further improve the conductivity while maintaining high transmittance, we introduce silver nanowires (AgNWs between rGO and a PET substrate to obtain a hybrid rGO/AgNWs/PET with a sheet resistance of ~100 Ω/sq and 81% transmittance. In addition, the hybrid rGO/AgNWs thin film also shows high flexibility and durability and is suitable for flexible and wearable electronics applications.

  14. Fasting substrate oxidation in relation to habitual dietary fat intake and insulin resistance in non-diabetic women: a case for metabolic flexibility?

    Directory of Open Access Journals (Sweden)

    Carstens Madelaine T

    2013-01-01

    Full Text Available Abstract Background Metabolic flexibility described as “the capacity of the body to match fuel oxidation to fuel availability” has been implicated in insulin resistance. We examined fasting substrate oxidation in relation to dietary macronutrient intake, and markers of insulin resistance in otherwise healthy women, with and without a family history of diabetes mellitus (FH DM. Methods We measured body composition (dual x-ray absorptiometry, visceral and subcutaneous adipose tissue area (VAT, SAT, using Computerised Tomography, fasting [glucose], [insulin], [free fatty acids], [blood lipids], insulin resistance (HOMA-IR, resting energy expenditure (REE, respiratory exchange ratio(RER and self-reported physical activity in a convenience sample of 180 women (18-45 yrs. A food frequency questionnaire was used to assess energy intake (EI and calculate the RER: Food Quotient (FQ ratio. Only those with EI:REE (1.05 -2.28 were included (N=140. Insulin resistance was defined HOMA-IR (>1.95. Results The Insulin Resistant (IR group had higher energy, carbohydrate and protein intakes (p 2 = 0.50, p  Conclusion In these apparently healthy, weight-stable women, insulin resistance and FH DM were associated with lower fat oxidation in relation to dietary fat intake, suggesting lower metabolic flexibility.

  15. Low-temperature deposited ZnO thin films on the flexible substrate by cathodic vacuum arc technology

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ru-Yuan, E-mail: ryyang@mail.npust.edu.tw [Department of Materials Engineering, National Ping-Tung University of Science and Technology, Taiwan (China); Weng, Min-Hang [Medical Devices and Opto-electronics Equipment Department, Metal Industries Research and Development Center, Taiwan (China); Pan, Cheng-Tang [Department of Mechanical and Electron-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung County 804, Taiwan (China); Hsiung, Chin-Min; Huang, Chun-Chih [Department of Mechanical Engineering, National Ping-Tung University of Science and Technology, Taiwan (China)

    2011-06-01

    In this paper, un-doped zinc oxide (ZnO) films with various thicknesses (150, 250, 350, 450 and 550 nm) were successfully prepared onto PET substrates using cathodic vacuum arc technique at low-temperature (<40 deg. C). Their microstructure, optical and electrical properties were investigated and discussed. The films showed (0 0 2) peaks, an average transmittance over 80% in the visible region. Calculated values of the band gap are around 3.29-3.33 eV when the film thickness increased, indicating a slight blue shift of optical transmission spectra. The lowest resistivity about 5.26 x 10{sup -3} {Omega} cm could be achieved for the un-doped ZnO film with thickness of 550 nm.

  16. Flexible one diode-one phase change memory array enabled by block copolymer self-assembly.

    Science.gov (United States)

    Mun, Beom Ho; You, Byoung Kuk; Yang, Se Ryeun; Yoo, Hyeon Gyun; Kim, Jong Min; Park, Woon Ik; Yin, You; Byun, Myunghwan; Jung, Yeon Sik; Lee, Keon Jae

    2015-04-28

    Flexible memory is the fundamental component for data processing, storage, and radio frequency communication in flexible electronic systems. Among several emerging memory technologies, phase-change random-access memory (PRAM) is one of the strongest candidate for next-generation nonvolatile memories due to its remarkable merits of large cycling endurance, high speed, and excellent scalability. Although there are a few approaches for flexible phase-change memory (PCM), high reset current is the biggest obstacle for the practical operation of flexible PCM devices. In this paper, we report a flexible PCM realized by incorporating nanoinsulators derived from a Si-containing block copolymer (BCP) to significantly lower the operating current of the flexible memory formed on plastic substrate. The reduction of thermal stress by BCP nanostructures enables the reliable operation of flexible PCM devices integrated with ultrathin flexible diodes during more than 100 switching cycles and 1000 bending cycles.

  17. All-inkjet-printed flexible electronics fabrication on a polymer substrate by low-temperature high-resolution selective laser sintering of metal nanoparticles

    Science.gov (United States)

    Ko, Seung H.; Pan, Heng; Grigoropoulos, Costas P.; Luscombe, Christine K.; Fréchet, Jean M. J.; Poulikakos, Dimos

    2007-08-01

    All-printed electronics is the key technology to ultra-low-cost, large-area electronics. As a critical step in this direction, we demonstrate that laser sintering of inkjet-printed metal nanoparticles enables low-temperature metal deposition as well as high-resolution patterning to overcome the resolution limitation of the current inkjet direct writing processes. To demonstrate this process combined with the implementation of air-stable carboxylate-functionalized polythiophenes, high-resolution organic transistors were fabricated in ambient pressure and room temperature without utilizing any photolithographic steps or requiring a vacuum deposition process. Local thermal control of the laser sintering process could minimize the heat-affected zone and the thermal damage to the substrate and further enhance the resolution of the process. This local nanoparticle deposition and energy coupling enable an environmentally friendly and cost-effective process as well as a low-temperature manufacturing sequence to realize large-area, flexible electronics on polymer substrates.

  18. All-inkjet-printed flexible electronics fabrication on a polymer substrate by low-temperature high-resolution selective laser sintering of metal nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Seung H [Department of Mechanical Engineering, University of California, 6177 Etcheverry Hall, Berkeley, CA 94720-1740 (United States); Pan Heng [Department of Mechanical Engineering, University of California, 6177 Etcheverry Hall, Berkeley, CA 94720-1740 (United States); Grigoropoulos, Costas P [Department of Mechanical Engineering, University of California, 6177 Etcheverry Hall, Berkeley, CA 94720-1740 (United States); Luscombe, Christine K [Department of Chemistry, University of California, Berkeley, CA 94720-1460 (United States); Frechet, Jean M J [Department of Chemistry, University of California, Berkeley, CA 94720-1460 (United States); Poulikakos, Dimos [Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zurich, CH-8092 Zurich (Switzerland)

    2007-08-29

    All-printed electronics is the key technology to ultra-low-cost, large-area electronics. As a critical step in this direction, we demonstrate that laser sintering of inkjet-printed metal nanoparticles enables low-temperature metal deposition as well as high-resolution patterning to overcome the resolution limitation of the current inkjet direct writing processes. To demonstrate this process combined with the implementation of air-stable carboxylate-functionalized polythiophenes, high-resolution organic transistors were fabricated in ambient pressure and room temperature without utilizing any photolithographic steps or requiring a vacuum deposition process. Local thermal control of the laser sintering process could minimize the heat-affected zone and the thermal damage to the substrate and further enhance the resolution of the process. This local nanoparticle deposition and energy coupling enable an environmentally friendly and cost-effective process as well as a low-temperature manufacturing sequence to realize large-area, flexible electronics on polymer substrates.

  19. Flexible Hybrid Organic-Inorganic Perovskite Memory.

    Science.gov (United States)

    Gu, Chungwan; Lee, Jang-Sik

    2016-05-24

    Active research has been done on hybrid organic-inorganic perovskite materials for application to solar cells with high power conversion efficiency. However, this material often shows hysteresis, which is undesirable, shift in the current-voltage curve. The hysteresis may come from formation of defects and their movement in perovskite materials. Here, we utilize the defects in perovskite materials to be used in memory operations. We demonstrate flexible nonvolatile memory devices based on hybrid organic-inorganic perovskite as the resistive switching layer on a plastic substrate. A uniform perovskite layer is formed on a transparent electrode-coated plastic substrate by solvent engineering. Flexible nonvolatile memory based on the perovskite layer shows reproducible and reliable memory characteristics in terms of program/erase operations, data retention, and endurance properties. The memory devices also show good mechanical flexibility. It is suggested that resistive switching is done by migration of vacancy defects and formation of conducting filaments under the electric field in the perovskite layer. It is believed that organic-inorganic perovskite materials have great potential to be used in high-performance, flexible memory devices.

  20. Ultrasensitive nanostructure sensor arrays on flexible substrates for multiplexed and simultaneous electrochemical detection of a panel of cardiac biomarkers.

    Science.gov (United States)

    Radha Shanmugam, Nandhinee; Muthukumar, Sriram; Chaudhry, Shajee; Anguiano, Jonathan; Prasad, Shalini

    2017-03-15

    Multiplexed detection of protein biomarkers offers new opportunities for early diagnosis and efficient treatment of complex diseases. Cardiovascular diseases (CVDs) has the highest mortality risk in USA and Europe with 15-20 million cases being reported annually. Cardiac Troponins (T and I) are well established protein biomarkers associated with heart muscle damage and point-of-care monitoring of both these two biomarkers has significant benefits on patient care. A flexible disposable electrochemical biosensor device comprising of vertically oriented zinc oxide (ZnO) nanostructures was developed for rapid and simultaneous screening of cardiac Troponin-I (cTnI) and cardiac-Troponin-T (cTnT) in a point-of-care sensor format. The biosensors were designed by selective hydrothermal growth of ZnO nanostructures onto the working electrodes of polyimide printed circuit board platforms, resulting in the generation of high density nanostructure ZnO arrays based electrodes. The size, density and surface terminations of the nanostructures were leveraged towards achieving surface confinement of the target cTnT and cTnI molecules on to the electrode surface. Multiplexing and simultaneous detection was achieved through sensor platform design comprising of arrays of Troponin functionalized ZnO nanostructure electrodes. The sensitivity and specificity of the biosensor was characterized using two types of electrochemical techniques; electrochemical impedance spectroscopy (EIS) and Mott-Schottky analysis on the same sensor platform to demonstrate multi-configurable modes. Limit of detection of 1pg/mL in human serum was achieved for both cTnI and cTnT. Cross reactivity analysis showed the selectivity of detecting cTnT and cTnI in human serum with wide dynamic range.

  1. Microfabrication of plastic-PDMS microfluidic devices using polyimide release layer and selective adhesive bonding

    Science.gov (United States)

    Wang, Shuyu; Yu, Shifeng; Lu, Ming; Zuo, Lei

    2017-05-01

    In this paper, we present an improved method to bond poly(dimethylsiloxane) (PDMS) with polyimide (PI) to develop flexible substrate microfluidic devices. The PI film was separately fabricated on a silicon wafer by spin coating followed by thermal treatment to avoid surface unevenness of the flexible substrate. In this way, we could also integrate flexible substrate into standard micro-electromechanical systems (MEMS) fabrication. Meanwhile, the adhesive epoxy was selectively transferred to the PDMS microfluidic device by a stamp-and-stick method to avoid epoxy clogging the microfluidic channels. To spread out the epoxy evenly on the transferring substrate, we used superhydrophilic vanadium oxide film coated glass as the transferring substrate. After the bonding process, the flexible substrate could easily be peeled off from the rigid substrate. Contact angle measurement was used to characterize the hydrophicity of the vanadium oxide film. X-ray photoelectron spectroscopy analysis was conducted to study the surface of the epoxy. We further evaluated the bonding quality by peeling tests, which showed a maximum bonding strength of 100 kPa. By injecting with black ink, the plastic microfluidic device was confirmed to be well bonded with no leakage for a day under 1 atm. This proposed versatile method could bond the microfluidic device and plastic substrate together and be applied in the fabrication of some biosensors and lab-on-a-chip systems.

  2. Fabrication of anti-adhesion surfaces on aluminium substrates of rubber plastic moulds using electrolysis plasma treatment

    Science.gov (United States)

    Meng, Jianbing; Dong, Xiaojuan; Wei, Xiuting; Yin, Zhanmin

    2015-04-01

    An anti-adhesion surface with a water contact angle of 167° was fabricated on aluminium samples of rubber plastic moulds by electrolysis plasma treatment using mixed electrolytes of C6H5O7(NH4)3 and Na2SO4, followed by fluorination. To optimise the fabrication conditions, several important processing parameters such as the discharge voltage, discharge time, concentrations of supporting electrolyte and stearic acid ethanol solution were examined systematically. Using scanning electron microscopy (SEM) to analyse surfaces morphology, micrometer scale pits, and protrusions were found on the surface, with numerous nanometer mastoids contained in the protrusions. These binary micro/nano-scale structures, which are similar to the micro-structures of soil-burrowing animals, play a critical role in achieving low adhesion properties. Otherwise, the anti-adhesion behaviours of the resulting samples were analysed by the atomic force microscope (AFM), Fourier-transform infrared spectrophotometer (FTIR), electrons probe micro-analyzer (EPMA), optical contact angle meter, digital Vickers microhardness (Hv) tester, and electronic universal testing. The results show that the electrolysis plasma treatment does not require complex processing parameters, using a simple device, and is an environment-friendly and effective method. Under the optimised conditions, the contact angle (CA) for the modified anti-adhesion surface is up to 167°, the sliding angle (SA) is less than 2°, roughness of the sample surface is only 0.409μm. Moreover, the adhesion force and Hv are 0. 9KN and 385, respectively.

  3. Fabrication of anti-adhesion surfaces on aluminium substrates of rubber plastic moulds using electrolysis plasma treatment

    Directory of Open Access Journals (Sweden)

    Jianbing Meng

    2015-04-01

    Full Text Available An anti-adhesion surface with a water contact angle of 167° was fabricated on aluminium samples of rubber plastic moulds by electrolysis plasma treatment using mixed electrolytes of C6H5O7(NH43 and Na2SO4, followed by fluorination. To optimise the fabrication conditions, several important processing parameters such as the discharge voltage, discharge time, concentrations of supporting electrolyte and stearic acid ethanol solution were examined systematically. Using scanning electron microscopy (SEM to analyse surfaces morphology, micrometer scale pits, and protrusions were found on the surface, with numerous nanometer mastoids contained in the protrusions. These binary micro/nano-scale structures, which are similar to the micro-structures of soil-burrowing animals, play a critical role in achieving low adhesion properties. Otherwise, the anti-adhesion behaviours of the resulting samples were analysed by the atomic force microscope (AFM, Fourier-transform infrared spectrophotometer (FTIR, electrons probe micro-analyzer (EPMA, optical contact angle meter, digital Vickers microhardness (Hv tester, and electronic universal testing. The results show that the electrolysis plasma treatment does not require complex processing parameters, using a simple device, and is an environment-friendly and effective method. Under the optimised conditions, the contact angle (CA for the modified anti-adhesion surface is up to 167°, the sliding angle (SA is less than 2°, roughness of the sample surface is only 0.409μm. Moreover, the adhesion force and Hv are 0. 9KN and 385, respectively.

  4. A flexible and transparent graphene/ZnO nanorod hybrid structure fabricated by exfoliating a graphite substrate.

    Science.gov (United States)

    Nam, Gwang-Hee; Baek, Seong-Ho; Cho, Chang-Hee; Park, Il-Kyu

    2014-10-21

    We demonstrate the fabrication of a graphene/ZnO nanorod (NR) hybrid structure by mechanical exfoliation of ZnO NRs grown on a graphite substrate. We confirmed the existence of graphene sheets on the hybrid structure by analyzing the Raman spectra and current-voltage (I-V) characteristics. The Raman spectra of the exfoliated graphene/ZnO NR hybrid structure show G and 2D band peaks that are shifted to lower wavenumbers, indicating that the exfoliated graphene layer exists under a significant amount of strain. The I-V characteristics of the graphene/ZnO NR hybrid structure show current flow through the graphene layer, while no current flow is observed on the ZnO NR/polydimethylsiloxane (PDMS) composite without graphene, thereby indicating that the few-layer graphene was successfully transferred onto the hybrid structure. A piezoelectric nanogenerator is demonstrated by using the fabricated graphene/ZnO NR hybrid structure. The nanogenerator exhibits stable output voltage up to 3.04 V with alternating current output characteristics.

  5. Ultra-Low Level Detection of L-Histidine Using Solution-Processed ZnO Nanorod on Flexible Substrate.

    Science.gov (United States)

    Sasmal, Milan; Maiti, Tapas Kumar; Bhattacharyya, Tarun Kanti

    2015-09-01

    This work demonstrates a novel label free and sensitive approach for the detection of L-histidine. This is a simple and reliable method for ultra-low level detection of L-histidine. All solution processed synthesizing technique was utilized to develop such type of detection scheme. Silicon substrate was replaced by normal transparent sheet to make it more facile and cost-effective detection technique. Fabricated device for L-histidine detection works upon the variation of current through the ZnO nanorod with L-histidine concentration. Operation principle strongly depends upon the electron charge transfer between metal cation and L-histidine inside the chelating complex. Morphological, structural and optical characterization of solution processed synthesized ZnO nanorod (ZnO NR) was carried out prior to sensor device fabrication. Our sensor device exhibits the sensitivity around 0.86 nA/fM and lower limit of detection (LOD) ∼ 0.1 fM(S/N=3).

  6. Biodegradability of Plastics

    OpenAIRE

    Yutaka Tokiwa; Calabia, Buenaventurada P.; Charles U. Ugwu; Seiichi Aiba

    2009-01-01

    Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical ...

  7. A screen-printed flexible flow sensor

    Science.gov (United States)

    Moschos, A.; Syrovy, T.; Syrova, L.; Kaltsas, G.

    2017-04-01

    A thermal flow sensor was printed on a flexible plastic substrate using exclusively screen-printing techniques. The presented device was implemented with custom made screen-printed thermistors, which allows simple, cost-efficient production on a variety of flexible substrates while maintaining the typical advantages of thermal flow sensors. Evaluation was performed for both static (zero flow) and dynamic conditions using a combination of electrical measurements and IR imaging techniques in order to determine important characteristics, such as temperature response, output repeatability, etc. The flow sensor was characterized utilizing the hot-wire and calorimetric principles of operation, while the preliminary results appear to be very promising, since the sensor was successfully evaluated and displayed adequate sensitivity in a relatively wide flow range.

  8. Indium-free Cu/fluorine doped ZnO composite transparent conductive electrodes with stretchable and flexible performance on poly(ethylene terephthalate) substrate

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jun; Gong, Haibo; Yang, Xiaopeng; Qiu, Zhiwen; Zi, Min; Qiu, Xiaofeng [Key Lab of Inorganic Functional Material in Universities of Shandong, School of Material Science and Engineering, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Wang, Hongqiang [Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool, Peach Street, Liverpool L69 7ZF (United Kingdom); Cao, Bingqiang, E-mail: mse_caobq@ujn.edu.cn [Key Lab of Inorganic Functional Material in Universities of Shandong, School of Material Science and Engineering, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China)

    2015-03-30

    Graphical abstract: - Highlights: • Cu/FZO bilayer films grow on PET substrates at room temperature. • The lowest resistivity of 6.6 × 10{sup −5} Ω cm is obtained. • The Cu/FZO film exhibits mechanical flexibility and stability. - Abstract: Material-abundant ZnO and metal thin film have been proposed as potential alternatives for the most widely commercial indium tin oxide (ITO) transparent and conductive electrode. Yet the deterioration of optical transparency and conductivity for these materials makes them difficult to compete with ITO. In this work, a double-layer structured film-composed of FZO and Cu film is presented at room temperature, which combines the high transparency of FZO and high conductivity of Cu film. We first studied the effect of oxygen pressure on the transparency and conductivity of free-standing FZO layer deposited on poly(ethylene terephthalate) (PET) by PLD method. Also the structural, electrical, and optical properties of bilayers electrode dependence on the Cu layer thickness were optimized in detail. As the Cu layer thickness increases, the resistivity decreases. The lowest resistivity of 6.6 × 10{sup −5} Ω cm with a carrier concentration of 1.11 × 10{sup 22} cm{sup −3} and mobility of 8.52 cm{sup 2} V{sup −1} s{sup −1} was obtained at the optimum Cu (12 nm) layer thickness. We find that FZO layer have anti-reflection effect for Cu/FZO (250 nm) bilayer in the wavelength range of 650–1000 nm compared with single Cu layer. And we firstly study the stretchable performance for Cu film-based composite electrodes with stretching ratio changing from 0 to 5%. Furthermore, we study excellent mechanical flexibility and stability of composite electrodes by bending test.

  9. Silver-Nanoparticle-Based Screen-Printing and Film Characterization of a Disposable, Dual-Band, Bandstop Filter on a Flexible Polyethylene Terephthalate Substrate

    Directory of Open Access Journals (Sweden)

    Kishor Kumar Adhikari

    2015-01-01

    Full Text Available This paper presents a silver-nanoparticle-based, screen-printed, high-performance, dual-band, bandstop filter (DBBSF on a flexible polyethylene terephthalate (PET substrate. Using screen-printing techniques to process a highly viscous silver printing ink, high-conductivity printed lines were implemented at a web transfer speed of 5 m/min. Characterized by X-ray diffraction (XRD, optical microscopy, atomic force microscopy (AFM, and scanning electron microscopy (SEM, the printed lines were shown to be characterized by smooth surfaces with a root mean square roughness of 7.986 nm; a significantly higher thickness (12.2 μm than the skin depth; and a high conductivity of 2×107 S/m. These excellent printed line characteristics enabled the implementation of a high-selectivity DBBSF using shunt-connected uniform impedance resonators (UIRs. Additionally, the inductive loading effect of T-shaped stubs on the UIRs, which were analyzed using S-parameters based on lumped parameter calculations, was used to improve the return losses of the geometrically optimized DBBSF. The measured minimum return loss and maximum insertion loss of 28.26 and 1.58 dB, respectively, at the central frequencies of 2.56 and 5.29 GHz of a protocol screen-printed DBBSF demonstrated the excellent performance of the material and its significant potential for use in future cost-effective, flexible WiMax and WLAN applications.

  10. Flexible CIGS solar cells and mini-modules (Flexcim)

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, A. N.

    2007-08-15

    This final report for the Swiss Federal Office of Energy (SFOE) reports on a project that has contributed significantly to further developments in the field of Cu(In,Ga)Se{sub 2} thin film solar cells on flexible substrates such as plastic and metal foils. Process optimisation at low temperature deposition conditions is reported on that have resulted in a new world record of the highest achieved solar conversion efficiency for any solar cell on plastic substrate: cells with an efficiency of 14.1% were obtained. Efficiencies beyond 15% are to be sought for by the reduction of reflection losses. The results obtained are presented in both illustrations and in graphical form. The authors state that more work, especially on up-scaling of CIGS deposition and further increasing the efficiency of flexible solar modules, is needed.

  11. 3-D Integrated Flexible Glass Photonics

    CERN Document Server

    Li, Lan; Qiao, Shutao; Zou, Yi; Danto, Sylvain; Richardson, Kathleen; Musgraves, J David; Lu, Nanshu; Hu, Juejun

    2013-01-01

    Photonic integration on plastic substrates enables emerging applications ranging from flexible interconnects to conformal sensors on biological tissues. Such devices are traditionally fabricated using pattern transfer, which is complicated and has limited integration capacity. Here we pioneered a monolithic approach to realize flexible, high-index-contrast glass photonics with significantly improved processing throughput and yield. Noting that the conventional multilayer bending theory fails when laminates have large elastic mismatch, we derived a mechanics theory accounting for multiple neutral axes in one laminated structure to accurately predict its strain-optical coupling behavior. Through combining monolithic fabrication and local neutral axis designs, we fabricated devices that boast record optical performance (Q=460,000) and excellent mechanical flexibility enabling repeated bending down to sub-millimeter radius without measurable performance degradation, both of which represent major improvements over...

  12. Flexible Cu(In,Ga)Se2 Thin-Film Solar Cells on Polyimide Substrate by Low-Temperature Deposition Process

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li; HE Qing; JIANG Wei-Long; LI Chang-Jian; SUN Yun

    2008-01-01

    The electrical and structural properties of polycrystalline Cu(In,Ga)Se2 films grown on polyimide (PI) substrates below 400℃ via one-stage and three-stage co-evaporation process have been investigated by x-ray diffraction spectra (XRD),scanning electron microscopy (SEM) and Hall effect measurement.As shown by XRD spectra,the stoichiometric CIGS films obtained by one-stage process exhibit the characteristic diffraction peaks of the (In0.68Ga0.32)2Se3 and Cu(In0.7Ga0.3)2Se.It is also found that the film structures indicate more columnar and compact than the three-stage process films from SEM images.The stoichiometric CIGS films obtained by three-stage process exhibit the coexistence of the secondary phase of (In0.68Ga0.32)2Se3,Cu2-xSe and Cu(In0.7Ga0.3)2Se.High net carrier concentration and sheet conductivity are also observed for this kind of film,related to the presence of Cu2-xSe phase.As a result,when the CIGS film growth temperature is below 400℃,the three-stage process is inefficient for solar cells.By using the one-stage co-evaporation process,the flexible CIGS solar cell on a PI substrate with the best conversion efficiency of 6.38% is demonstrated (active area 0.16cm2).

  13. Fertilization of Watermelon Grown with Wheat Straw Substrate in Passive Plastic Greenhouse%大棚西瓜秸秆基质栽培施肥量研究

    Institute of Scientific and Technical Information of China (English)

    袁培祥

    2013-01-01

    Fertilization was studied using watermelon "Xiuli' grown in wheat straw substrate in passive plastic greenhouse. The tests included 5 levels of chicken manure + ammonium phosphate. The measurements included plant growth, yield and fruit quality. With the levels tested in this experiment yield was increased with the increase of fertilizer amount, the best treatment was 30 kg chicken manure + 1.5 kg ammonium phosphate per plot(19.87 m2).%以西瓜品种秀丽为试材,在大棚中采用秸秆基质栽培,腐熟鸡粪+磷酸二铵作为施肥配方,分析比较了5种施肥量对西瓜生长发育、产量及品质的影响,结果表明,在一定施肥量的范围内,产量随施肥量的增加而增加,综合所有因素,最佳施肥配方为每小区腐熟鸡粪30 kg+磷酸二铵1.5 kg.

  14. Preparation of anti-adhesion surfaces on aluminium substrates of rubber plastic moulds using a coupling method of liquid plasma and electrochemical machining

    Directory of Open Access Journals (Sweden)

    Jianbing Meng

    2014-02-01

    Full Text Available Hard anti-adhesion surfaces, with low roughness and wear resistance, on aluminium substrates of rubber plastic moulds were fabricated via a new coupling method of liquid plasma and electrochemical machining. With the aid of liquid plasma thermal polishing and electrochemical anodic dissolution, micro/nano-scale binary structures were prepared as the base of the anti-adhesion surfaces. The anti-adhesion behaviours of the resulting aluminium surfaces were analysed by a surface roughness measuring instrument, a scanning electron microscope (SEM, a Fourier-transform infrared spectrophotometer (FTIR, an X-ray diffractometer (XRD, an optical contact angle meter, a digital Vickers micro-hardness (Hv tester, and electronic universal testing. The results show that, after the liquid plasma and electrochemical machining, micro/nano-scale binary structures composed of micro-scale pits and nano-scale elongated boss structures were present on the sample surfaces. As a result, the anti-adhesion surfaces fabricated by the above coupling method have good anti-adhesion properties, better wear resistance and lower roughness.

  15. Resistive switching characteristics of Cu/ZnO0.4S0.6/Al devices constructed on plastic substrates.

    Science.gov (United States)

    Han, Yong; Cho, Kyoungah; Kim, Sangsig

    2012-07-01

    In this study, Cu/ZnO0.4S0.6Al devices are fabricated on plastic substrates using the sputtering method at room temperature. The ratio of O/S in the zinc oxysulfide thin film is confirmed to be 0.4/0.6 from the Auger depth profiling. The Cu/ZnO0.4S0.6/Al devices show unipolar resistive switching behaviors and the ratio of the measured resistance in the low-resistance state (LRS) to that in the high-resistance state (HRS) is above 10(4). The conduction mechanism of the LRS is governed by Ohm's law. On the other hand, in the HRS, the conduction mechanism at low voltages is controlled by Ohm's law, but that at high voltages results from the Poole-Frenkel emission mechanism. The Ohmic and Poole-Frenkel conduction mechanisms observed in the LRS and HRS support the filament model of unipolar resistive switching. The memory characteristics of the Cu/ZnO0.4S0.6/Al devices are retained for 10(4) sec without any change.

  16. Flexible spin-orbit torque devices

    Energy Technology Data Exchange (ETDEWEB)

    Lee, OukJae; You, Long; Jang, Jaewon; Subramanian, Vivek [Department of Electrical Engineering and Computer Sciences, University of California at Berkeley, Berkeley, California 94720 (United States); Salahuddin, Sayeef [Department of Electrical Engineering and Computer Sciences, University of California at Berkeley, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2015-12-21

    We report on state-of-the-art spintronic devices synthesized and fabricated directly on a flexible organic substrate. Large perpendicular magnetic anisotropy was achieved in ultrathin ferromagnetic heterostructures of Pt/Co/MgO sputtered on a non-rigid plastic substrate at room temperature. Subsequently, a full magnetic reversal of the Co was observed by exploiting the spin orbit coupling in Pt that leads to a spin accumulation at the Pt/Co interface when an in-plane current is applied. Quasi-static measurements show the potential for operating these devices at nano-second speeds. Importantly, the behavior of the devices remained unchanged under varying bending conditions (up to a bending radius of ≈ ±20–30 mm). Furthermore, the devices showed robust operation even after application of 10{sup 6} successive pulses, which is likely sufficient for many flexible applications. Thus, this work demonstrates the potential for integrating high performance spintronic devices on flexible substrates, which could lead to many applications ranging from flexible non-volatile magnetic memory to local magnetic resonance imaging.

  17. Design and development of plasmonic nanostructured electrodes for ITO-free organic photovoltaic cells on rigid and highly-flexible substrates.

    Science.gov (United States)

    Richardson, Beau; Zhu, Leize; Yu, Qiuming

    2017-03-01

    Indium tin oxide (ITO) is the most common transparent electrode used in organic photovoltaics (OPVs), yet limited indium reserves and poor mechanical properties make it non-ideal for large-scale OPV production. To replace ITO, we designed, fabricated, and deployed plasmonic nanostructured electrodes in inverted OPV devices. We found that active layer absorption is significantly impacted by ZnO thickness which affects the optical field distribution inside the resonant cavity formed between the plasmonic nanostructured electrode and top electrode. High quality Cr/Au nanostructured electrodes were fabricated by nanoimprint lithography and deployed in ITO-free inverted devices on glass. Devices with thinner ZnO showed a PCE as high as 5.70% and higher JSC's than devices on thicker ZnO, in agreement with Finite-Difference Time-Domain (FDTD) simulations. In addition, as the active layer was made optically thin, ITO-based devices showed diminished JSC while the resonant cavity effect from plasmonic nanostructured electrodes retained JSC. Preliminary ITO-free, flexible devices on PET showed a PCE of 1.82% and those fabricated on ultrathin and conformable Parylene substrates yielded an initial PCE over 1%. The plasmonic electrodes and device designs in this work show promise for developing highly functioning conformable devices that can be applied to numerous needs for lightweight, ubiquitous power generation.

  18. Microstructure and Electrical Properties of Antimony Telluride Thin Films Deposited by RF Magnetron Sputtering on Flexible Substrate Using Different Sputtering Pressures

    Science.gov (United States)

    Khumtong, T.; Sukwisute, P.; Sakulkalavek, A.; Sakdanuphab, R.

    2017-02-01

    The microstructural, electrical, and thermoelectric properties of antimony telluride (Sb2Te3) thin films have been investigated for thermoelectric applications. Sb2Te3 thin films were deposited on flexible substrate (polyimide) by radiofrequency (RF) magnetron sputtering from a Sb2Te3 target using different sputtering pressures in the range from 4 × 10-3 mbar to 1.2 × 10-2 mbar. The crystal structure, [Sb]:[Te] ratio, and electrical and thermoelectric properties of the films were analyzed by grazing-incidence x-ray diffraction (XRD) analysis, energy-dispersive x-ray spectroscopy (EDS), and Hall effect and Seebeck measurements, respectively. The XRD spectra of the films demonstrated polycrystalline structure with preferred orientation of (015), (110), and (1010). A high-intensity spectrum was found for the film deposited at lower sputtering pressure. EDS analysis of the films revealed the effects of the sputtering pressure on the [Sb]:[Te] atomic ratio, with nearly stoichiometric films being obtained at higher sputtering pressure. The stoichiometric Sb2Te3 films showed p-type characteristics with electrical conductivity, carrier concentration, and mobility of 35.7 S cm-1, 6.38 × 1019 cm-3, and 3.67 cm2 V-1 s-1, respectively. The maximum power factor of 1.07 × 10-4 W m-1 K-2 was achieved for the film deposited at sputtering pressure of 1.0 × 10-2 mbar.

  19. Using Flexible Polyimide as a Substrate to Deposit ZnO:Ga Thin Films and Fabricate p-i-n α-Si:H Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Fang-Hsing Wang

    2013-01-01

    Full Text Available The GZO thin films were deposited on the polyimide (PI substrates to investigate their properties for the possibly flexible applications. The effects of substrate temperature (from room temperature to 200°C on the surface and cross-session morphologies, X-ray diffraction pattern, optical transmission spectrum, carrier concentration, carrier mobility, and resistivity of the GZO thin films on PI substrates were studied. The measured results showed that the substrate temperature had large effect on the characteristics of the GZO thin films. The cross-section observations really indicated that the GZO thin films deposited at 200°C and below had different crystalline structures. The value variations in the films’ optical band gap (Eg of the GZO thin films were evaluated from plots of  (αhν2=c(hν-Eg, revealing that the measured Eg values increased with increasing deposition temperature. Finally, the prepared GZO thin films were also used as the transparent electrodes to fabricate the α-Si amorphous silicon thin-film solar cells on the flexible PI substrates, and the properties of which were also measured. We would also prove that substrate temperature of the GZO thin films had large effect on the characteristics of the fabricated α-Si amorphous silicon thin-film solar cells.

  20. Biodegradability of plastics.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P; Ugwu, Charles U; Aiba, Seiichi

    2009-08-26

    Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  1. Biodegradability of Plastics

    Directory of Open Access Journals (Sweden)

    Yutaka Tokiwa

    2009-08-01

    Full Text Available Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.. In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  2. 多层柔性衬底电路板的低成本丝网印刷%Low Cost Printed Flexible Multilayer Substrates

    Institute of Scientific and Technical Information of China (English)

    胡新颖

    2009-01-01

    For high-volume products, such as mobile terminals, low cost techniques for multilayer polymer-based thick film wiring board manufacturing are needed. Screen-printing is a cost efficient technology candidate to build up approximately 6 conductor layers on both sides of a flexible substrate, for example. In order to experimentally evaluate the feasibility of screen-printing technique, the printing resolution was tested on different substrate materials, such as, polycarbonate (PC), polyethylene terephtalate (PET), polyimide (PI) and liquid crystal polymer (LCP), Conventional screen printed polymer thick film pastes were characterized on polymer substrates to form multilayer fine-line patterning and through-hole vias.The final demonstrator was a double-sided PI substrate having two conductor layers separated by dielectric layers on both sides of the substrate and through substrate vias. The screen printed conductor material was an Ag-based nano particle ink and the dielectric layer was a polyimide-based material.Several challenges were identified that might hinder the applicability of the technology for mass-production. The stability of the polyimide substrate is a problem if the curing temperature of the printed materials is above 200"C. Layer-to-layer alignment tolerances are feasible if the printed area is small, 5"x5", in our case. The flatness of the substrate, however,is not very good after printing several layers on each other. The tested nano particle ink is a promising conductor system; however, lowering of the curing temperature from 230℃ below 200℃ would have a major impact on production friendliness. Another way to realise multilayer structures is to utilise lamination methods. In this study PET and PC sheets were also used. The focus in the processing development was on the deposition of adhesive layer over the PET sheet and the lamination process. Vias and conductors needed in multilayer structures were realised by utilising conventional thick

  3. Bioinspired Transparent Laminated Composite Film for Flexible Green Optoelectronics.

    Science.gov (United States)

    Lee, Daewon; Lim, Young-Woo; Im, Hyeon-Gyun; Jeong, Seonju; Ji, Sangyoon; Kim, Yong Ho; Choi, Gwang-Mun; Park, Jang-Ung; Lee, Jung-Yong; Jin, Jungho; Bae, Byeong-Soo

    2017-07-19

    Herein, we report a new version of a bioinspired chitin nanofiber (ChNF) transparent laminated composite film (HCLaminate) made of siloxane hybrid materials (hybrimers) reinforced with ChNFs, which mimics the nanofiber-matrix structure of hierarchical biocomposites. Our HCLaminate is produced via vacuum bag compressing and subsequent UV-curing of the matrix resin-impregnated ChNF transparent paper (ChNF paper). It is worthwhile to note that this new type of ChNF-based transparent substrate film retains the strengths of the original ChNF paper and compensates for ChNF paper's drawbacks as a flexible transparent substrate. As a result, compared with high-performance synthetic plastic films, such as poly(ethylene terephthalate), poly(ether sulfone), poly(ethylene naphthalate), and polyimide, our HCLaminate is characterized to exhibit extremely smooth surface topography, outstanding optical clarity, high elastic modulus, high dimensional stability, etc. To prove our HCLaminate as a substrate film, we use it to fabricate flexible perovskite solar cells and a touch-screen panel. As far as we know, this work is the first to demonstrate flexible optoelectronics, such as flexible perovskite solar cells and a touch-screen panel, actually fabricated on a composite film made of ChNF. Given its desirable macroscopic properties, we envision our HCLaminate being utilized as a transparent substrate film for flexible green optoelectronics.

  4. Optogenetic Stimulation of Peripheral Vagus Nerves using Flexible OLED Display Technology to Treat Chronic Inflammatory Disease and Mental Health Disorders

    Science.gov (United States)

    2016-03-31

    and veterans, including arthritis, systemic inflammatory response syndrome, inflammatory bowel disease, post -traumatic stress disorder (PTSD...provide the desired specificity and minimize unwanted physiological side effects during treatment. Low Cost Mass Production Technology The notional...transcutaneous VNS OLED ‘bandage’ would be manufactured on a thin plastic substrate using commercial thin- film , flexible-display technology

  5. Flexible Thermoelectric Generators on Silicon Fabric

    KAUST Repository

    Sevilla, Galo T.

    2012-11-01

    In this work, the development of a Thermoelectric Generator on Flexible Silicon Fabric is explored to extend silicon electronics for flexible platforms. Low cost, easily deployable plastic based flexible electronics are of great interest for smart textile, wearable electronics and many other exciting applications. However, low thermal budget processing and fundamentally limited electron mobility hinders its potential to be competitive with well established and highly developed silicon technology. The use of silicon in flexible electronics involve expensive and abrasive materials and processes. In this work, high performance flexible thermoelectric energy harvesters are demonstrated from low cost bulk silicon (100) wafers. The fabrication of the micro- harvesters was done using existing silicon processes on silicon (100) and then peeled them off from the original substrate leaving it for reuse. Peeled off silicon has 3.6% thickness of bulk silicon reducing the thermal loss significantly and generating nearly 30% more output power than unpeeled harvesters. The demonstrated generic batch processing shows a pragmatic way of peeling off a whole silicon circuitry after conventional fabrication on bulk silicon wafers for extremely deformable high performance integrated electronics. In summary, by using a novel, low cost process, this work has successfully integrated existing and highly developed fabrication techniques to introduce a flexible energy harvester for sustainable applications.

  6. Water- and humidity-enhanced UV detector by using p-type La-doped ZnO nanowires on flexible polyimide substrate.

    Science.gov (United States)

    Hsu, Cheng-Liang; Li, Hsieh-Heng; Hsueh, Ting-Jen

    2013-11-13

    High-density La-doped ZnO nanowires (NWs) were grown hydrothermally on flexible polyimide substrate. The length and diameter of the NWs were around 860 nm and 80-160 nm, respectively. All XRD peaks of the La-doped sample shift to a larger angle. The strong PL peak of the La-doped sample is 380 nm, which is close to the 3.3 eV ZnO bandgap. That PL dominated indicates that the La-doped sample has a great amount of oxygen vacancies. The lattice constants ~0.514 nm of the ZnO:La NW were smaller when measured by HR-TEM. The EDX spectrum determined that the La-doped sample contains approximately 1.27 at % La. The La-doped sample was found to be p-type by Hall Effect measurement. The dark current of the p-ZnO:La NWs decreased with increased relative humidity (RH), while the photocurrent of the p-ZnO:La nanowires increased with increased RH. The higher RH environment was improved that UV response performance. Based on the highest 98% RH, the photocurrent/dark current ratio was around 47.73. The UV response of water drops on the p-ZnO:La NWs was around 2 orders compared to 40% RH. In a water environment, the photocurrent/dark current ratio of p-ZnO:La NWs was 212.1, which is the maximum UV response.

  7. Improved continuity of reduced graphene oxide on polyester fabric by use of polypyrrole to achieve a highly electro-conductive and flexible substrate

    Energy Technology Data Exchange (ETDEWEB)

    Berendjchi, Amirhosein [Department of Textile Engineering, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Khajavi, Ramin, E-mail: khajavi@azad.ac.ir [Nano Technology Research Center, South Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Yousefi, Ali Akbar [Faculty of Polymer Processing, Iran Polymer and Petrochemical Institute, Tehran (Iran, Islamic Republic of); Yazdanshenas, Mohammad Esmail [Department of Textile Engineering, Yazd Branch, Islamic Azad University, Yazd (Iran, Islamic Republic of)

    2016-02-15

    Graphical abstract: - Highlights: • Discontinuity of reduced graphene oxide (RGO) coated polyester fabric (PET) substrate was overcome by filling the gaps by in situ chemical oxidative polymerization of polypyrrole (PPy). • The RGO–PPy coated samples exhibited 53% and 263% lower surface resistivity values (5 Ω/sq) than samples coated only with PPy (12 Ω/sq) and RGO (1300 Ω/sq), respectively. • The RGO–PPy coated fabric displayed other properties, such as excellent UV blocking (UPF = 73), antibacterial activity, improved electrochemical behavior and thermal stability which make it a multifunctional fabric. - Abstract: A flexible and highly conductive fabric can be applied for wearable electronics and as a pliable counter electrode for photovoltaics. Methods such as surface coating of fabrics with conductive polymers and materials have been developed, but the roughness of fabric is a challenge because it creates discontinuity in the coated layer. The present study first coated polyethylene terephthalate (PET) fabric with reduced graphene oxide sheets; RGO and then filled the gaps with polypyrrole (PPy). The samples were first dipped in graphene oxide (GO) and then reduced to RGO. They were next coated with PPy by in situ polymerization. The results showed that the presence of oxidative agent during synthesis of PPy oxidized the RGO to some extent on the previously RGO-coated samples. PPy was more uniform on samples pre-coated with RGO in comparison those coated with raw PET. The RGO–PPy coated samples exhibited 53% and 263% lower surface resistivity values than samples coated only with PPy and RGO, respectively. There was no significant difference between the tenacity of samples but the bending rigidity of samples increased. The RGO–PPy coated fabric displayed properties, such as excellent UV blocking (UPF = 73), antibacterial activity, improved electrochemical behavior and thermal stability which make it a multifunctional fabric.

  8. Ultraviolet–Visible photo-response of p-Cu{sub 2}O/n-ZnO heterojunction prepared on flexible (PET) substrate

    Energy Technology Data Exchange (ETDEWEB)

    Elfadill, Nezar G., E-mail: abualneez999@yahoo.com [Nano-Optoelectronics Research and Technology Laboratory, School of Physics University Sains Malaysia, Penang 11800 (Malaysia); Hashim, M.R.; Saron, K.M.A.; Chahrour, Khaled M.; Qaeed, M.A. [Nano-Optoelectronics Research and Technology Laboratory, School of Physics University Sains Malaysia, Penang 11800 (Malaysia); Bououdina, M. [Nanotechnology Centre, College of Science, University of Bahrain, P.O. Box 32038 (Bahrain); Department of Physics, College of Science, University of Bahrain, P.O. Box 32038 (Bahrain)

    2015-04-15

    The deposition of monocrystalline ZnO nanostructures (using different concentration of reaction solution) on Cu{sub 2}O thin film by hydrothermal method is reported. The mechanism of growing different ZnO nanostructures i.e. nanoneedles, nanotubes and nanorods are explained based on the gradient of Zn{sup +} species (resulting from precipitation) in reaction solution. The UV-VIS photo-detection properties of the three selected p-Cu{sub 2}O/n-ZnO heterojunctions are studied by illuminated I–V characteristic and the wavelength dependent photo-responsivity properties. The spectral responsivity curves can be divided into three regions (1.9–2.17 eV), (2.2–2.9 eV) and (>3.2 eV) denoted as A, B and C. The regions A and C are assigned for band to band level absorption in Cu{sub 2}O and ZnO respectively, while region C is associated with a combination of two absorption process: part of photons were absorbed by the band to deep level absorption in ZnO and the transmitted photons were absorbed in Cu{sub 2}O. It is found that the heterojunctions with nanotubes exhibit higher responsivity than other nanostructures, which is mainly due to the large surface-to-volume ratio. - Highlights: • Fabrication of p-Cu{sub 2}O/n-ZnO heterojunction on flexible PET substrate. • Synthesis of different ZnO nanostructures i.e. nanoneedles, nanotubes and nanorods. • The UV-VIS photo-detection properties of p-Cu{sub 2}O/n-ZnO heterojunctions.

  9. Electrical and photocatalytic properties of boron-doped ZnO nanostructure grown on PET-ITO flexible substrates by hydrothermal method.

    Science.gov (United States)

    Wang, Wei; Ai, Taotao; Yu, Qi

    2017-02-13

    Boron-doped zinc oxide sheet-spheres were synthesized on PET-ITO flexible substrates using a hydrothermal method at 90 °C for 5 h. The results of X-ray diffraction and X-ray photoelectron spectroscopy indicated that the B atoms were successfully doped into the ZnO lattice, the incorporation of B led to an increase in the lattice constant of ZnO and a change in its internal stress. The growth mechanism of pure ZnO nanorods and B-doped ZnO sheet-spheres was specifically investigated. The as-prepared BZO/PET-ITO heterojunction possessed obvious rectification properties and its positive turn-on voltage was 0.4 V. The carrier transport mechanisms involved three models such as hot carrier tunneling theory, tunneling recombination, and series-resistance effect were explored. The BZO/PET-ITO nanostructures were more effective than pure ZnO to degrade the RY 15, and the degradation rate reached 41.45%. The decomposition process with BZO nanostructure followed first-order reaction kinetics. The photocurrent and electrochemical impedance spectroscopy revealed that the B-doping could promote the separation of photo-generated electron-hole pairs, which was beneficial to enhance the photocatalytic activity. The photocurrent density of B-doped and pure ZnO/PET-ITO were 0.055 mA/cm(2) and 0.016 mA/cm(2), respectively. The photocatalytic mechanism of the sample was analyzed by the energy band theory.

  10. Electrical and photocatalytic properties of boron-doped ZnO nanostructure grown on PET–ITO flexible substrates by hydrothermal method

    Science.gov (United States)

    Wang, Wei; Ai, Taotao; Yu, Qi

    2017-02-01

    Boron-doped zinc oxide sheet-spheres were synthesized on PET–ITO flexible substrates using a hydrothermal method at 90 °C for 5 h. The results of X-ray diffraction and X-ray photoelectron spectroscopy indicated that the B atoms were successfully doped into the ZnO lattice, the incorporation of B led to an increase in the lattice constant of ZnO and a change in its internal stress. The growth mechanism of pure ZnO nanorods and B-doped ZnO sheet-spheres was specifically investigated. The as-prepared BZO/PET–ITO heterojunction possessed obvious rectification properties and its positive turn-on voltage was 0.4 V. The carrier transport mechanisms involved three models such as hot carrier tunneling theory, tunneling recombination, and series-resistance effect were explored. The BZO/PET–ITO nanostructures were more effective than pure ZnO to degrade the RY 15, and the degradation rate reached 41.45%. The decomposition process with BZO nanostructure followed first-order reaction kinetics. The photocurrent and electrochemical impedance spectroscopy revealed that the B-doping could promote the separation of photo-generated electron-hole pairs, which was beneficial to enhance the photocatalytic activity. The photocurrent density of B-doped and pure ZnO/PET–ITO were 0.055 mA/cm2 and 0.016 mA/cm2, respectively. The photocatalytic mechanism of the sample was analyzed by the energy band theory.

  11. A highly reliable copper nanowire/nanoparticle ink pattern with high conductivity on flexible substrate prepared via a flash light-sintering technique.

    Science.gov (United States)

    Joo, Sung-Jun; Park, Sung-Hyeon; Moon, Chang-Jin; Kim, Hak-Sung

    2015-03-18

    In this work, copper nanowires (NWs) and Cu nanoparticles (NPs) were employed to increase the reliability of a printed electrode pattern under mechanical bending fatigue. The fabricated Cu NW/NP inks with different weight fractions of Cu NWs were printed on a polyimide substrate and flash light-sintered within a few milliseconds at room temperature under ambient conditions. Then, 1000 cycles of outer and inner bending fatigue tests were performed using a lab-made fatigue tester. The flash light-sintered Cu NW/NP ink film with 5 wt % Cu NWs prepared under the flash light-sintering conditions (12.5 J·cm–2 irradiation energy, 10 ms pulse duration, and one pulse) showed a lower resistivity (22.77 μΩ·cm) than those of the only Cu NPs and Cu NWs ink (94.01 μΩ·cm and 104.15 μΩ·cm, respectively). In addition, the resistance change (ΔR·R0(–1)) of the 5 wt % Cu NWs Cu NW/NP film was greatly enhanced to 4.19 compared to the 92.75 of the Cu NPs film obtained under mechanical fatigue conditions over 1000 cycles and an outer bending radius of 7 mm. These results were obtained by the densification and enhanced mechanical flexibility of flash light-sintered Cu NW/NP network, which resulted in prevention of crack initiation and propagation. To characterize the Cu NW/NP ink film, X-ray diffraction and scanning electron microscopy were used.

  12. Room-temperature preparation and dielectric properties of amorphous Bi3.95Er0.05Ti3O12 thin films on flexible polyimide substrates via pulsed laser deposition method

    Science.gov (United States)

    Mo, Zhong; Wu, Guangheng; Bao, Dinghua

    2012-05-01

    Bi3.95Er0.05Ti3O12 (BErT) thin films were prepared on flexible polyimide (PI) substrates at room temperature by pulsed laser deposition. These BErT thin films deposited under low oxygen pressures are dense, uniform, and crack-free with an amorphous structure. The highly flexible thin film with a thickness of about 160 nm deposited under 3 Pa oxygen pressure shows excellent dielectric characteristics, such as a dielectric constant of 51 and a dielectric loss of 0.025, and a maximum capacitance density of 237 nF/cm2 at 1 kHz. When it is curved at different curvature radii (by applying external deformation), the thin film still remains superior dielectric performance. In addition, the thin film also shows good dielectric aging characteristic (or thermal stability) and high optical transparency. BErT thin films can find applications in flexible optoelectronic devices and embedded capacitors.

  13. Flexible Electronics Powered by Mixed Metal Oxide Thin Film Transistors

    Science.gov (United States)

    Marrs, Michael

    A low temperature amorphous oxide thin film transistor (TFT) and amorphous silicon PIN diode backplane technology for large area flexible digital x-ray detectors has been developed to create 7.9-in. diagonal backplanes. The critical steps in the evolution of the backplane process include the qualification and optimization of the low temperature (200 °C) metal oxide TFT and a-Si PIN photodiode process, the stability of the devices under forward and reverse bias stress, the transfer of the process to flexible plastic substrates, and the fabrication and assembly of the flexible detectors. Mixed oxide semiconductor TFTs on flexible plastic substrates suffer from performance and stability issues related to the maximum processing temperature limitation of the polymer. A novel device architecture based upon a dual active layer improves both the performance and stability. Devices are directly fabricated below 200 ºC on a polyethylene naphthalate (PEN) substrate using mixed metal oxides of either zinc indium oxide (ZIO) or indium gallium zinc oxide (IGZO) as the active semiconductor. The dual active layer architecture allows for adjustment to the saturation mobility and threshold voltage stability without the requirement of high temperature annealing, which is not compatible with flexible plastic substrates like PEN. The device performance and stability is strongly dependent upon the composition of the mixed metal oxide; this dependency provides a simple route to improving the threshold voltage stability and drive performance. By switching from a single to a dual active layer, the saturation mobility increases from 1.2 cm2/V-s to 18.0 cm2/V-s, while the rate of the threshold voltage shift decreases by an order of magnitude. This approach could assist in enabling the production of devices on flexible substrates using amorphous oxide semiconductors. Low temperature (200°C) processed amorphous silicon photodiodes were developed successfully by balancing the tradeoffs

  14. STUDY ON MICROCRYSTALLINE SILICON THIN FILM SOLAR CELLS ON FLEXIBLE SUBSTRATE%柔性衬底微晶硅薄膜太阳电池研究

    Institute of Scientific and Technical Information of China (English)

    周丽华; 刘成; 叶晓军; 钱子勍; 陈鸣波

    2011-01-01

    The intrinsic microcrystalline silicon thin film layers (I-layer) and nip single microcrystalline silicon solar cells were prepared by plasma enhanced chemical vapor deposition (PECVD). Then the relationship among deposition parameters, the characteristics of I-layers and the performanceof solar cells was studied. It demonstrated that crystalline fraction of I-layers decreased gradually with the increasing of silicon concentration. And the performance of solar cells deteriorated while the deposition temperature rose over 200℃. With the increasing of discharge power, the crystalline volume fraction maintained the same, but the open circuit voltage of the solar cell and its spectrum response at short wavelength increased gradually. Base on the optimized deposition parameters, single junction solar cells with conversion efficiency of 6.48% (AM0,25℃ ) were fabricated. Finally, tandem solar cells on stainless steel flexible substrate with conversion efficiency of 9. 28% ( AM0,25℃) were obtained.%采用等离子增强化学气相沉积(PECVD)技术制备了系列本征微晶硅薄膜材料和nip单结微晶硅太阳电池,研究了硅烷浓度、衬底温度和辉光功率等沉积参数与薄膜材料性能、薄膜电池性能三者之间的关系.拉曼光谱和器件测试结果表明:随硅烷浓度的增加,本征层晶化率逐渐减小,直至转变为非晶硅;沉积温度高于200℃时,电池性能严重恶化;随等离子辉光功率增加,材料晶化率保持不变,而电池开路电压逐渐增大,短波光谱响应逐渐增强.在此基础上,优化了单结微晶硅电池沉积参数,得到效率为6.48% (AM0,25℃)的单结微晶硅薄膜太阳电池;并将其应用到非晶硅/微晶硅叠层电池中,在不锈钢柔性衬底上得到效率为9.28%( AM0,25℃)的叠层电池.

  15. Spatial atomic layer deposition on flexible porous substrates: ZnO on anodic aluminum oxide films and Al{sub 2}O{sub 3} on Li ion battery electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Kashish [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309 (United States); Routkevitch, Dmitri; Varaksa, Natalia [InRedox, Longmont, Colorado 80544 (United States); George, Steven M., E-mail: Steven.George@Colorado.Edu [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309 and Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309 (United States)

    2016-01-15

    Spatial atomic layer deposition (S-ALD) was examined on flexible porous substrates utilizing a rotating cylinder reactor to perform the S-ALD. S-ALD was first explored on flexible polyethylene terephthalate polymer substrates to obtain S-ALD growth rates on flat surfaces. ZnO ALD with diethylzinc and ozone as the reactants at 50 °C was the model S-ALD system. ZnO S-ALD was then performed on nanoporous flexible anodic aluminum oxide (AAO) films. ZnO S-ALD in porous substrates depends on the pore diameter, pore aspect ratio, and reactant exposure time that define the gas transport. To evaluate these parameters, the Zn coverage profiles in the pores of the AAO films were measured using energy dispersive spectroscopy (EDS). EDS measurements were conducted for different reaction conditions and AAO pore geometries. Substrate speeds and reactant pulse durations were defined by rotating cylinder rates of 10, 100, and 200 revolutions per minute (RPM). AAO pore diameters of 10, 25, 50, and 100 nm were utilized with a pore length of 25 μm. Uniform Zn coverage profiles were obtained at 10 RPM and pore diameters of 100 nm. The Zn coverage was less uniform at higher RPM values and smaller pore diameters. These results indicate that S-ALD into porous substrates is feasible under certain reaction conditions. S-ALD was then performed on porous Li ion battery electrodes to test S-ALD on a technologically important porous substrate. Li{sub 0.20}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} electrodes on flexible metal foil were coated with Al{sub 2}O{sub 3} using 2–5 Al{sub 2}O{sub 3} ALD cycles. The Al{sub 2}O{sub 3} ALD was performed in the S-ALD reactor at a rotating cylinder rate of 10 RPM using trimethylaluminum and ozone as the reactants at 50 °C. The capacity of the electrodes was then tested versus number of charge–discharge cycles. These measurements revealed that the Al{sub 2}O{sub 3} S-ALD coating on the electrodes enhanced the capacity stability. This S

  16. Flexible magnetoimpidence sensor

    KAUST Repository

    Kavaldzhiev, Mincho

    2015-05-01

    Recently, flexible electronic devices have attracted increasing interest, due to the opportunities they promise for new applications such as wearable devices, where the components are required to flex during normal use[1]. In this light, different magnetic sensors, like microcoil, spin valve, giant magnetoresistance (GMR), magnetoimpedance (MI), have been studied previously on flexible substrates.

  17. Flexible graphene-PZT ferroelectric nonvolatile memory

    Science.gov (United States)

    Lee, Wonho; Kahya, Orhan; Tat Toh, Chee; Özyilmaz, Barbaros; Ahn, Jong-Hyun

    2013-11-01

    We report the fabrication of a flexible graphene-based nonvolatile memory device using Pb(Zr0.35,Ti0.65)O3 (PZT) as the ferroelectric material. The graphene and PZT ferroelectric layers were deposited using chemical vapor deposition and sol-gel methods, respectively. Such PZT films show a high remnant polarization (Pr) of 30 μC cm-2 and a coercive voltage (Vc) of 3.5 V under a voltage loop over ±11 V. The graphene-PZT ferroelectric nonvolatile memory on a plastic substrate displayed an on/off current ratio of 6.7, a memory window of 6 V and reliable operation. In addition, the device showed one order of magnitude lower operation voltage range than organic-based ferroelectric nonvolatile memory after removing the anti-ferroelectric behavior incorporating an electrolyte solution. The devices showed robust operation in bent states of bending radii up to 9 mm and in cycling tests of 200 times. The devices exhibited remarkable mechanical properties and were readily integrated with plastic substrates for the production of flexible circuits.

  18. Plastic Surgery

    Science.gov (United States)

    ... Surgery? A Week of Healthy Breakfasts Shyness Plastic Surgery KidsHealth > For Teens > Plastic Surgery Print A A ... forehead lightened with a laser? What Is Plastic Surgery? Just because the name includes the word "plastic" ...

  19. Reciclagem de embalagens plásticas flexíveis: contribuição da identificação correta Flexible plastic packaging recycling: the contribution of the correct identification

    Directory of Open Access Journals (Sweden)

    Leda Coltro

    2013-01-01

    , folha de alumínio, é proposta a inclusão da identificação destes materiais na embalagem.Packages have high rotation as they become municipal solid waste just after the consumption of the product. Therefore, packages should be labeled with identification of the material they are made of in order to help the recycling chain. Many products made from plastics show a resin identification code - usually from 1 to 7 inside a three-arrow triangle above a monogram - aimed at identifying the type of plastic the product is made of, and help its separation and later recycling. In other words, one aims to facilitate recovery of plastics discarded with the municipal solid waste. In this study we collected data on the resin identification code in flexible plastic packages to assess whether the guidelines for material identification are being followed. The data collection was performed in a total of 509 flexible plastic packages used for packing food and non-food products available in the Brazilian market. Even though the NBR 13230 Brazilian standard is already in its second revision, the resin identification code in plastic packages is still used in a very heterogeneous fashion. Approximately 50% of the packages had the resin identification code. Up to 30% of some packages showed incorrect material identification code. Therefore, misinformation still occurs in the Brazilian market concerning the type of material for plastic packaging - including lack of the resin identification code and incorrect form of identification code in the plastic packaging. Both of these problems have negative effects on the plastic recycling chain. We propose that other materials used in flexible plastic packages, e.g. aluminum foil, should also be identified, in order to make the separation and recycling easier.

  20. Properties of low-temperature deposited ZnO thin films prepared by cathodic vacuum arc technology on different flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Cheng-Tang [Department of Mechanical and Electron-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung City 804, Taiwan (China); Yang, Ru-Yuan, E-mail: ryyang@mail.npust.edu.tw [Graduate Institute of Materials Engineering, National Pingtung University of Science and Technology, Pingtung County 912, Taiwan (China); Weng, Min-Hang [Medical Devices and Opto-Electronics Equipment Department, Metal Industries Research and Development Center, Kaohsiung City 821, Taiwan (China); Huang, Chien-Wei [Department of Mechanical and Electron-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung City 804, Taiwan (China)

    2013-07-31

    Un-doped zinc oxide (ZnO) films were deposited on three different substrates (polyethylene terephthalate (PET), polyvinyl butyral (PVB) and polyimide (PI)) at a low temperature (< 75 °C) by cathode vacuum arc deposition. The microstructure, optical and electrical properties of the deposited films were investigated and discussed. All the deposited films reveal a preferred orientation with the c-axis perpendicular to the substrate, and an average transmittance of over 85% in the visible region. The calculated optical band gaps are around 2.6, 3.14 and 3.18 eV, respectively, for the ZnO films deposited on the PI, PVB and PET substrates. The lowest resistivity and the highest Hall mobility are 5.31 × 10{sup −3} Ω-cm and 15.16 cm{sup 2}/V-s for the ZnO film deposited on the PET substrate. - Highlights: • Polyethylene terephthalate, polyvinyl butyral and polyimide were used as substrates. • ZnO films were prepared by cathodic arc plasma deposition. • ZnO films have different properties due to different substrates. • The microstructure control of ZnO film on polymer substrate is important.

  1. Single-Walled Carbon Nanotubes for Flexible Electronics and Sensors

    Institute of Scientific and Technical Information of China (English)

    Xiuyun SUN; Yugang SUN

    2008-01-01

    This article reviews the use of electronic quality single-walled carbon nanotubes grown via chemical vapor deposition (CVD) approaches at high temperatures as building blocks for fabricating flexible field-effect devices, such as thin-film transistors (TFTs) and chemical sensors. Dry transfer printing technique is developed for forming films of CVD nanotubes on low-temperature plastic substrates. Examples of TFTs with the use of nanotubes and thin dielectrics and hydrogen sensors with the use of nanotubes decorated with palladium nanoparticles are discussed in detail to demonstrate the promising potentiality of single-walled carbon nanotubes for building high performance flexible devices, which can find applications where traditional devices on rigid substrates are not suitable.

  2. Studies on different configurations of cobalt phthalocyanine based flexible organic field effect transistor

    Science.gov (United States)

    Kumar, A.; Jha, P.; Samanta, S.; Singh, A.; Debnath, A. K.; Aswal, D. K.; Gupta, S. K.

    2016-05-01

    Organic Field Effect Transistors (OFETs) are being investigated for a number of low-cost, large area applications; particularly those that are compatible with flexible plastic substrates. Development of low temperature processes can make way for OFETs to be integrated on flexible plastic substrates. Here we have made systematic studies on OFETs in different configurations wherein we have chosen Cobalt Phthalocyanine (CoPc) as active material. We have found the best mobility (1.86 × 10-5 cm2/V-s) in Bottom Gate Top Contact configuration. However, threshold voltage (-5V) and On off ratio (62)were found to be better in Top Gate Bottom Contact configuration The electromechanical properties of the Bottom Gate Top Contact transistors were studied by measuring the transfer characteristics of the devices in bend condition and thereby calculating mobility under different radii of bending. No significant change in the mobility of the device was observed under bent conditions.

  3. Biaxial stress and optoelectronic properties of Al-doped ZnO thin films deposited on flexible substrates by radio frequency magnetron sputtering.

    Science.gov (United States)

    Chen, Hsi-Chao; Cheng, Po-Wei; Huang, Kuo-Ting

    2017-02-01

    Transparent conductive Al-doped ZnO (AZO) thin films were deposited on polyethylene terephthalate (PET) and polycarbonate (PC) substrates using radio frequency (RF) magnetron sputtering. The biaxial stress was measured with a double beam shadow moiré interferometer, and x-ray diffraction (XRD) was used to investigate the crystal orientation of ZnO. The substrate temperature was varied from room temperature to 150°C in steps of 25°C. The experimental results showed that the residual and shearing stresses increased with the increase in substrate temperature. The residual stress can be separated into principle and shearing stresses by Mohr's circle rule, and the shearing stress (tensile stress) was different from the compressive stress of the residual stress. However, the optimal substrate temperatures for PET and PC were 75°C and 100°C, and the shearing stresses were 424.82 and 543.68 MPa, respectively. AZO/PET and AZO/PC thin films cracked at substrate temperatures of 75°C and 100°C, respectively. AZO/PET thin film at a substrate temperature of 100°C had a resistivity low to the order of 10-3  Ω-cm.

  4. Polymer Ferroelectric Memory for Flexible Electronics

    KAUST Repository

    Khan, Mohd Adnan

    2013-11-01

    With the projected growth of the flexible and plastic electronics industry, there is renewed interest in the research community to develop high performance all-polymeric memory which will be an essential component of any electronic circuit. Some of the efforts in polymer memories are based on different mechanisms such as filamentary conduction, charge trapping effects, dipole alignment, and reduction-oxidation to name a few. Among these the leading candidate are those based on the mechanism of ferroelectricity. Polymer ferroelectric memory can be used in niche applications like smart cards, RFID tags, sensors etc. This dissertation will focus on novel material and device engineering to fabricate high performance low temperature polymeric ferroelectric memory for flexible electronics. We address and find solutions to some fundamental problems affecting all polymer ferroelectric memory like high coercive fields, fatigue and thermal stability issues, poor breakdown strength and poor p-type hole mobilities. Some of the strategies adopted in this dissertation are: Use of different flexible substrates, electrode engineering to improve charge injection and fatigue properties of ferroelectric polymers, large area ink jet printing of ferroelectric memory devices, use of polymer blends to improve insulating properties of ferroelectric polymers and use of oxide semiconductors to fabricate high mobility p-type ferroelectric memory. During the course of this dissertation we have fabricated: the first all-polymer ferroelectric capacitors with solvent modified highly conducting polymeric poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) [PEDOT:PSS] electrodes on plastic substrates with performance as good as devices with metallic Platinum-Gold electrodes on silicon substrates; the first all-polymer high performance ferroelectric memory on banknotes for security applications; novel ferroelectric capacitors based on blends of ferroelectric poly(vinylidene fluoride

  5. How plasticity, genetic assimilation and cryptic genetic variation may contribute to adaptive radiations.

    Science.gov (United States)

    Schneider, Ralf F; Meyer, Axel

    2017-01-01

    There is increasing evidence that phenotypic plasticity can promote population divergence by facilitating phenotypic diversification and, eventually, genetic divergence. When a 'plastic' population colonizes a new habitat, it has the possibility to occupy multiple niches by expressing several distinct phenotypes. These initially reflect the population's plastic range but may later become genetically fixed by selection via the process of 'genetic assimilation' (GA). Through this process multiple specialized sister lineages can arise that share a common plastic ancestor - the 'flexible stem'. Here, we review possible molecular mechanisms through which natural selection could fix an initially plastic trait during GA. These mechanisms could also explain how GA may contribute to cryptic genetic variation that can subsequently be coopted into other phenotypes or traits, but also lead to nonadaptive responses. We outline the predicted patterns of genetic and transcriptional divergence accompanying flexible stem radiations. The analysis of such patterns of (retained) adaptive and nonadaptive plastic responses within and across radiating lineages can inform on the state of ongoing GA. We conclude that, depending on the stability of the environment, the molecular architecture underlying plastic traits can facilitate diversification, followed by fixation and consolidation of an adaptive phenotype and degeneration of nonadaptive ones. Additionally, the process of GA may increase the cryptic genetic variation of populations, which on one hand may serve as substrate for evolution, but on another may be responsible for nonadaptive responses that consolidate local allopatry and thus reproductive isolation.

  6. Highly Flexible and High-Performance Complementary Inverters of Large-Area Transition Metal Dichalcogenide Monolayers

    KAUST Repository

    Pu, Jiang

    2016-03-23

    Complementary inverters constructed from large-area monolayers of WSe2 and MoS2 achieve excellent logic swings and yield an extremely high gain, large total noise margin, low power consumption, and good switching speed. Moreover, the WSe2 complementary-like inverters built on plastic substrates exhibit high mechanical stability. The results provide a path toward large-area flexible electronics. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Carbon fibre reinforced plastic knee-ankle-foot orthosis with a partially flexible thigh cuff: a modification for comfort while sitting on a toilet seat.

    Science.gov (United States)

    Hachisuka, K; Arai, K; Arai, M

    2007-06-01

    At the request of a polio survivor, a partially flexible thigh cuff made of leather and canvas for a carbon KAFO was devised to allow the wearer to feel more comfortable while sitting on a toilet seat. The original, acrylic resin, thigh cuff was partially excised to make an opening (15x10 cm), which was stuffed with rubber sponge, and was sealed with leather and canvas. The opening's surround was vertically and horizontally reinforced with carbon fibres. This modification provided relief to the polio survivor from the discomfort previously experienced while sitting on a toilet seat, and satisfied her needs in daily life.

  8. Fully printed flexible carbon nanotube photodetectors

    Science.gov (United States)

    Zhang, Suoming; Cai, Le; Wang, Tongyu; Miao, Jinshui; Sepúlveda, Nelson; Wang, Chuan

    2017-03-01

    Here, we report fully printed flexible photodetectors based on single-wall carbon nanotubes and the study of their electrical characteristics under laser illumination. Due to the photothermal effect and the use of high purity semiconducting carbon nanotubes, the devices exhibit gate-voltage-dependent photoresponse with the positive photocurrent or semiconductor-like behavior (conductivity increases at elevated temperatures) under positive gate biases and the negative photocurrent or metal-like behavior (conductivity decreases at elevated temperatures) under negative gate biases. Mechanism for such photoresponse is attributed to the different temperature dependencies of carrier concentration and carrier mobility, which are two competing factors that ultimately determine the photothermal effect-based photoresponse. The photodetectors built on the polyimide substrate also exhibit superior mechanical compliance and stable photoresponse after thousands of bending cycles down to a curvature radius as small as 3 mm. Furthermore, due to the low thermal conductivity of the plastic substrate, the devices show up to 6.5 fold improvement in responsivity compared to the devices built on the silicon substrate. The results presented here provide a viable path to low cost and high performance flexible photodetectors fabricated entirely by the printing process.

  9. Solution-processed flexible fluorine-doped indium zinc oxide thin-film transistors fabricated on plastic film at low temperature.

    Science.gov (United States)

    Seo, Jin-Suk; Jeon, Jun-Hyuck; Hwang, Young Hwan; Park, Hyungjin; Ryu, Minki; Park, Sang-Hee Ko; Bae, Byeong-Soo

    2013-01-01

    Transparent flexible fluorine-doped indium zinc oxide (IZO:F) thin-film transistors (TFTs) were demonstrated using the spin-coating method of the metal fluoride precursor aqueous solution with annealing at 200°C for 2 hrs on polyethylene naphthalate films. The proposed thermal evolution mechanism of metal fluoride aqueous precursor solution examined by thermogravimetric analysis and Raman spectroscopy can easily explain oxide formation. The chemical composition analysed by XPS confirms that the fluorine was doped in the thin films annealed below 250°C. In the IZO:F thin films, a doped fluorine atom substitutes for an oxygen atom generating a free electron or occupies an oxygen vacancy site eliminating an electron trap site. These dual roles of the doped fluorine can enhance the mobility and improve the gate bias stability of the TFTs. Therefore, the transparent flexible IZO:F TFT shows a high mobility of up to 4.1 cm(2)/V·s and stable characteristics under the various gate bias and temperature stresses.

  10. Performance analysis of flexible DSSC with binder addition

    Science.gov (United States)

    Muliani, Lia; Hidayat, Jojo; Anggraini, Putri Nur

    2016-04-01

    Flexible DSSC is one of modification of DSSC based on its substrate. Operating at low temperature, flexible DSSC requires a binder to improve particles interconnection. This research was done to compare the morphology and performance of flexible DSSC that was produced with binder-added and binder-free. TiO2 powder, butanol, and HCl were mixed for preparation of TiO2 paste. Small amount of titanium isopropoxide as binder was added into the mixture. TiO2 paste was deposited on ITO-PET plastic substrate with area of 1x1 cm2 by doctor blade method. Furthermore, SEM, XRD, and BET characterization were done to analyze morphology and surface area of the TiO2 photoelectrode microstructures. Dyed TiO2 photoelectrode and platinum counter electrode were assembled and injected by electrolyte. In the last process, flexible DSSCs were illuminated by sun simulator to do J-V measurement. As a result, flexible DSSC containing binder showed higher performance with photoconversion efficiency of 0.31%.

  11. Performance analysis of flexible DSSC with binder addition

    Energy Technology Data Exchange (ETDEWEB)

    Muliani, Lia; Hidayat, Jojo; Anggraini, Putri Nur, E-mail: putri.nur.anggraini@gmail.com [Research Center for Electronics and Telecommunications Indonesian Institute of Sciences (PPET-LIPI) Kampus LIPI, Jl. Sangkuriang, Bandung 40135 (Indonesia)

    2016-04-19

    Flexible DSSC is one of modification of DSSC based on its substrate. Operating at low temperature, flexible DSSC requires a binder to improve particles interconnection. This research was done to compare the morphology and performance of flexible DSSC that was produced with binder-added and binder-free. TiO{sub 2} powder, butanol, and HCl were mixed for preparation of TiO{sub 2} paste. Small amount of titanium isopropoxide as binder was added into the mixture. TiO{sub 2} paste was deposited on ITO-PET plastic substrate with area of 1x1 cm{sup 2} by doctor blade method. Furthermore, SEM, XRD, and BET characterization were done to analyze morphology and surface area of the TiO{sub 2} photoelectrode microstructures. Dyed TiO{sub 2} photoelectrode and platinum counter electrode were assembled and injected by electrolyte. In the last process, flexible DSSCs were illuminated by sun simulator to do J-V measurement. As a result, flexible DSSC containing binder showed higher performance with photoconversion efficiency of 0.31%.

  12. Characterization of the MoO3/Ag grids/MoO3 sandwich electrode deposited on flexible substrate via thermal deposition method

    Science.gov (United States)

    Wang, Chen-Tao; Ting, Chu-Chi; Li, Shan-Rong; Chu, Sheng-Yuan

    2016-09-01

    In this paper, we will discuss the characteristics of the flexible sandwich electrode. We fabricate the MoO3/Ag grids/MoO3 via thermal deposition method. We will measure the bending test and the optical and electric characteristics. The conclusion of the MoO3/Ag grids/MoO3 will compare with the MoO3/Ag film/MoO3 and ITO flexible electrodes. This sandwich electrode will increase the transmittance by less silver coverage but the MoO3/Ag grids/MoO3 have lower sheet resistance compared with MoO3/Ag film/MoO3. Therefore, we propose this new electrode structure is proper for application of OLEDs.

  13. Ductile film delamination from compliant substrates using hard overlayers

    Energy Technology Data Exchange (ETDEWEB)

    Cordill, M.J. [Erich Schmid Institute of Materials Science, Austrian Academy of Sciences (Austria); Marx, V.M.; Kirchlechner, C. [Max-Plank-Insitut für Eisenforschung GmbH, Düsseldorf (Germany)

    2014-11-28

    Flexible electronic devices call for copper and gold metal films to adhere well to polymer substrates. Measuring the interfacial adhesion of these material systems is often challenging, requiring the formulation of different techniques and models. Presented here is a strategy to induce well defined areas of delamination to measure the adhesion of copper films on polyimide substrates. The technique utilizes a stressed overlayer and tensile straining to cause buckle formation. The described method allows one to examine the effects of thin adhesion layers used to improve the adhesion of flexible systems. - Highlights: • Measuring the adhesion energies of ductile metal–polymer interfaces is difficult. • A Cu film would plastically deform under tensile strain without a Cr overlayer. • A Cr overlayer forces cracking and induces buckling between the crack fragments. • The adhesion energy of the metal–polymer interface can be measured.

  14. Single-grain Si thin-film transistors on flexible polyimide substrate fabricated from doctor-blade coated liquid-Si

    NARCIS (Netherlands)

    Zhang, J.; Trifunovic, M.; Van der Zwan, M.; Takagishi, H.; Kawajiri, R.; Shimoda, T.; Beenakker, C.I.M.; Ishihara, R.

    2013-01-01

    Solution process of silicon will provide high-speed transistor fabrication with low-cost by, for example, roll-to-roll process. In this paper, a low-temperature process (350 °C) is reported for fabrication of high-quality Si devices on a polyimide substrate from doctor-blade coated liquid-Si. With

  15. Conformational Flexibility of the C Terminus with Implications for Substrate Binding and Catalysis Revealed in a New Crystal Form of Deacetoxycephalosporin C Synthase

    NARCIS (Netherlands)

    Öster, Linda M.; Terwisscha van Scheltinga, Anke C.; Valegård, Karin; MacKenzie Hose, Alasdair; Dubus, Alain; Hajdu, Janos; Andersson, Inger

    2004-01-01

    Deacetoxycephalosporin C synthase (DAOCS) from Streptomyces clavuligerus catalyses the oxidative ring expansion of the penicillin nucleus into the nucleus of cephalosporins. The reaction requires dioxygen and 2-oxoglutarate as co-substrates to create a reactive iron–oxygen intermediate from a ferrou

  16. Single-grain Si thin-film transistors on flexible polyimide substrate fabricated from doctor-blade coated liquid-Si

    NARCIS (Netherlands)

    Zhang, J.; Trifunovic, M.; Van der Zwan, M.; Takagishi, H.; Kawajiri, R.; Shimoda, T.; Beenakker, C.I.M.; Ishihara, R.

    2013-01-01

    Solution process of silicon will provide high-speed transistor fabrication with low-cost by, for example, roll-to-roll process. In this paper, a low-temperature process (350 °C) is reported for fabrication of high-quality Si devices on a polyimide substrate from doctor-blade coated liquid-Si. With t

  17. Low Temperature Silicon Nitride by Hot Wire Chemical Vapour Deposition for the Use in Impermeable Thin Film Encapsulation on Flexible Substrates

    NARCIS (Netherlands)

    Spee, D.A.; van der Werf, C.H.M.; Rath, J.K.; Schropp, R.E.I.

    2011-01-01

    High quality non porous silicon nitride layers were deposited by hot wire chemical vapour deposition at substrate temperatures lower than 110 C. The layer properties were investigated using FTIR, reflection/transmission measurements and 1:6 buffered HF etching rate. A Si–H peak position of 2180 cm−1

  18. Shadowgraph studies of laser-assisted non-thermal structuring of thin layers on flexible substrates by shock-wave-induced delamination processes

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, Pierre, E-mail: pierre.lorenz@iom-leipzig.de [Leibniz-Institut für Oberflächenmodifizierung e. V., Permoserstraße 15, 04318 Leipzig (Germany); Smausz, Tomi [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary); MTA-SZTE Research Group on Photoacoustic Spectroscopy, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary); Csizmadia, Tamas [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary); Ehrhardt, Martin; Zimmer, Klaus [Leibniz-Institut für Oberflächenmodifizierung e. V., Permoserstraße 15, 04318 Leipzig (Germany); Hopp, Bela [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary)

    2015-05-01

    Highlights: • The shock-wave-induced film delamination (SWIFD) is a laser patterning process. • The SWIFD process of CIGS solar cells was studied by shadowgraph measurements. • The study presented that SWIFD allows the structuring of CIGS solar cells. • The dynamics of the delamination process was analyzed. - Abstract: The laser-assisted microstructuring of thin films especially for electronic applications without damaging the layers or the substrates is a challenge for the laser micromachining techniques. The laser-induced thin-film patterning by ablation of the polymer substrate at the rear side that is called ‘SWIFD’ – shock-wave-induced film delamination patterning has been demonstrated. This study focuses on the temporal sequence of processes that characterize the mechanism of this SWIFD process on a copper indium gallium selenide (CIGS) solar cell stacks on polyimide. For this purpose high-speed shadowgraph experiments were performed in a pump probe experimental set-up using a KrF excimer laser for ablating the rear side of the polyimide substrate and measuring the shock wave generation at laser ablation of the polymer substrate as well as the thin-film delamination. The morphology and size of the thin-film structures were studied by scanning electron microscopy (SEM). Furthermore, the composition after the laser treatment was analyzed by energy dispersive X-ray (EDX) spectroscopy. The shadowgraph experiments allow the time-dependent identification and evaluation of the shock wave formation, substrate bending, and delamination of the thin film in dependence on the laser parameters. These results will contribute to improve the physical understanding of the laser-induced delamination effect for thin-film patterning.

  19. Highly transparent, low-haze, hybrid cellulose nanopaper as electrodes for flexible electronics.

    Science.gov (United States)

    Xu, Xuezhu; Zhou, Jian; Jiang, Long; Lubineau, Gilles; Ng, Tienkhee; Ooi, Boon S; Liao, Hsien-Yu; Shen, Chao; Chen, Long; Zhu, J Y

    2016-06-16

    Paper is an excellent candidate to replace plastics as a substrate for flexible electronics due to its low cost, renewability and flexibility. Cellulose nanopaper (CNP), a new type of paper made of nanosized cellulose fibers, is a promising substrate material for transparent and flexible electrodes due to its potentially high transparency and high mechanical strength. Although CNP substrates can achieve high transparency, they are still characterized by high diffuse transmittance and small direct transmittance, resulting in high optical haze of the substrates. In this study, we proposed a simple methodology for large-scale production of high-transparency, low-haze CNP comprising both long cellulose nanofibrils (CNFs) and short cellulose nanocrystals (CNCs). By varying the CNC/CNF ratio in the hybrid CNP, we could tailor its total transmittance, direct transmittance and diffuse transmittance. By increasing the CNC content, the optical haze of the hybrid CNP could be decreased and its transparency could be increased. The direct transmittance and optical haze of the CNP were 75.1% and 10.0%, respectively, greatly improved from the values of previously reported CNP (31.1% and 62.0%, respectively). Transparent, flexible electrodes were fabricated by coating the hybrid CNP with silver nanowires (AgNWs). The electrodes showed a low sheet resistance (minimum 1.2 Ω sq(-1)) and a high total transmittance (maximum of 82.5%). The electrodes were used to make a light emitting diode (LED) assembly to demonstrate their potential use in flexible displays.

  20. Single Layer Broadband Anti-Reflective Coatings for Plastic Substrates Produced by Full Wafer and Roll-to-Roll Step-and-Flash Nano-Imprint Lithography

    Directory of Open Access Journals (Sweden)

    Pascal Buskens

    2013-08-01

    Full Text Available Anti-reflective coatings (ARCs are used to lower the reflection of light on the surface of a substrate. Here, we demonstrate that the two main drawbacks of moth eye-structured ARCs—i.e., the lack of suitable coating materials and a process for large area, high volume applications—can be largely eliminated, paving the way for cost-efficient and large-scale production of durable moth eye-structured ARCs on polymer substrates. We prepared moth eye coatings on polymethylmethacrylate (PMMA and polycarbonate using wafer-by-wafer step-and-flash nano-imprint lithography (NIL. The reduction in reflection in the visible field achieved with these coatings was 3.5% and 4.0%, respectively. The adhesion of the coating to both substrates was good. The moth eye coating on PMMA demonstrated good performance in three prototypical accelerated ageing tests. The pencil hardness of the moth eye coatings on both substrates was <4B, which is less than required for most applications and needs further optimization. Additionally, we developed a roll-to-roll UV NIL pilot scale process and produced moth eye coatings on polyethylene terephthalate (PET at line speeds up to two meters per minute. The resulting coatings showed a good replication of the moth eye structures and, consequently, a lowering in reflection of the coated PET of 3.0%.

  1. Single Layer Broadband Anti-Reflective Coatings for Plastic Substrates Produced by Full Wafer and Roll-to-Roll Step-and-Flash Nano-Imprint Lithography.

    Science.gov (United States)

    Burghoorn, Marieke; Roosen-Melsen, Dorrit; de Riet, Joris; Sabik, Sami; Vroon, Zeger; Yakimets, Iryna; Buskens, Pascal

    2013-08-27

    Anti-reflective coatings (ARCs) are used to lower the reflection of light on the surface of a substrate. Here, we demonstrate that the two main drawbacks of moth eye-structured ARCs-i.e., the lack of suitable coating materials and a process for large area, high volume applications-can be largely eliminated, paving the way for cost-efficient and large-scale production of durable moth eye-structured ARCs on polymer substrates. We prepared moth eye coatings on polymethylmethacrylate (PMMA) and polycarbonate using wafer-by-wafer step-and-flash nano-imprint lithography (NIL). The reduction in reflection in the visible field achieved with these coatings was 3.5% and 4.0%, respectively. The adhesion of the coating to both substrates was good. The moth eye coating on PMMA demonstrated good performance in three prototypical accelerated ageing tests. The pencil hardness of the moth eye coatings on both substrates was polyethylene terephthalate (PET) at line speeds up to two meters per minute. The resulting coatings showed a good replication of the moth eye structures and, consequently, a lowering in reflection of the coated PET of 3.0%.

  2. Single layer broadband anti-reflective coatings for plastic substrates produced by full wafer and roll-to-roll step-and-flash nano-imprint lithography

    NARCIS (Netherlands)

    Burghoorn, M.M.A.; Roosen-Melsen, D.A.; Riet, J.F.J. de; Sabik, S.; Vroon, Z.A.E.P.; Yakimets, I.; Buskens, P.J.P.

    2013-01-01

    Anti-reflective coatings (ARCs) are used to lower the reflection of light on the surface of a substrate. Here, we demonstrate that the two main drawbacks of moth eye-structured ARCs-i.e., the lack of suitable coating materials and a process for large area, high volume applications-can be largely

  3. One step spray-coated TiO2 electron-transport layers for decent perovskite solar cells on large and flexible substrates

    Science.gov (United States)

    Huang, Aibin; Zhu, Jingting; Zhou, Yijie; Yu, Yu; Liu, Yan; Yang, Songwang; Ji, Shidong; Lei, Lei; Jin, Ping

    2017-01-01

    Spray-coating as a facile and quantitative method was introduced to prepare thin and continuous TiO2 compact layers on different substrates for perovskite solar cells. The as-prepared film is highly transparent and smooth, which is of significance in perovskite solar cells to decrease incident light loss and facilitate the film cast and electric contact. The compact TiO2 layer shows excellent performance when coated with perovskite and assembled into a device. Since it provides unlimited substrate size, patterning function and the TiO2 used for spray-coating is well crystallized, this method has huge potential for mass production and great adaptability for a variety of applications.

  4. One step spray-coated TiO2 electron-transport layers for decent perovskite solar cells on large and flexible substrates.

    Science.gov (United States)

    Huang, Aibin; Zhu, Jingting; Zhou, Yijie; Yu, Yu; Liu, Yan; Yang, Songwang; Ji, Shidong; Lei, Lei; Jin, Ping

    2017-01-06

    Spray-coating as a facile and quantitative method was introduced to prepare thin and continuous TiO2 compact layers on different substrates for perovskite solar cells. The as-prepared film is highly transparent and smooth, which is of significance in perovskite solar cells to decrease incident light loss and facilitate the film cast and electric contact. The compact TiO2 layer shows excellent performance when coated with perovskite and assembled into a device. Since it provides unlimited substrate size, patterning function and the TiO2 used for spray-coating is well crystallized, this method has huge potential for mass production and great adaptability for a variety of applications.

  5. Preparation of carbon nanotubes as the conductive coating layer on flexible thermal-resistant substrate by permeating method and its residual stress analysis

    Science.gov (United States)

    Kuo, Wen-Kai; Huang, Szu-Chun; Yu, Hsin Her

    2014-03-01

    A polyarylate (PAR) substrate was first prepared by hot pressing and then carbon nanotubes (CNTs) were coated on its surface by a low-temperature spraying method. In order to eliminate the residual stress and enhance the adhesive ability between the substrate and the coated CNT layer, an optimal thermo-permeating process is proposed. The relationship between the thickness of the permeating layer and the residual stress of coating layers was investigated. Triple-layer structure models were provided to evaluate the residual stress of coating layers. The experimental results show that if the sample was treated by the optimal thermo-permeating process, its residual stress was dramatically reduced from 1.7×103 MPa to 0.45 Pa; meanwhile, its adhesive ability was intensively enhanced from 1B to 5B according to ASTM D3359 adhesion classifications.

  6. Flexible Flatfoot

    Science.gov (United States)

    ... this page. Please enable Javascript in your browser. Flexible Flatfoot What Is Flatfoot? Flatfoot is often a ... may develop as a result of a flatfoot. Flexible Flatfoot Flexible flatfoot is one of the most ...

  7. Functional Surface Coating on Cellulosic Flexible Substrates with Improved Water-Resistant and Antimicrobial Properties by Use of ZnO Nanoparticles

    Directory of Open Access Journals (Sweden)

    Xiaofei Tian

    2017-01-01

    Full Text Available It is of significant interest to create functional flexible surfaces that simultaneously exhibit high water-resistance and antimicrobial performances for medical or packaging applications. This study reported a synthesis of functional surface coating on flexible cellulose materials (filter papers with ZnO nanoparticles and binds of renewable soybean oil-based polymers. Self-aggregation of ZnO nanoparticles could form ZnO particles with two regular morphological patterns. Rather than a rod-like morphology, a flower-like ZnO benefited a promotion of surface hydrophobicity. Moreover, surface with the flower-like ZnO showed a 51.6% promotion on antimicrobial activities against Gram-negative bacteria (E. coli than the rod-like ZnO. A low binder/ZnO ratio of 0.2 led to a remarkable improvement on water repelling performances without negative effects on a coating adhesion of ZnO. Under this condition, a hydrophobic surface was achieved with a large static contact angle of 138° when applying ZnO nanoparticles at a dosage of 3 g m−2.

  8. Highly flexible, transparent and conducting CuS-nanosheet networks for flexible quantum-dot solar cells.

    Science.gov (United States)

    Xu, Zijie; Li, Teng; Zhang, Fayin; Hong, Xiaodan; Xie, Shuyao; Ye, Meidan; Guo, Wenxi; Liu, Xiangyang

    2017-03-17

    The rapid development of modern electronics has given rise to a higher demand for flexible and wearable energy sources. Flexible transparent conducting electrodes (TCEs) are one of the essential components of flexible/wearable thin-film solar cells (SCs). In this regard, we present highly transparent and conducting CuS-nanosheet (NS) networks with an optimized sheet resistance (Rs) as low as 50 Ω sq(-1) at 85% transmittance as a counter electrode (CE) for flexible quantum-dot solar cells (QDSCs). The CuS NS network electrode exhibits remarkable mechanical flexibility under bending tests compared to traditional ITO/plastic substrates and sputtered CuS films. Herein, CuS NS networks not only served as conducting films for collecting electrons from the external circuit, but also served as superior catalysts for reducing polysulfide (S(2-)/Sx(2-)) electrolytes. A power conversion efficiency (PCE) up to 3.25% was achieved for the QDSCs employing CuS NS networks as CEs, which was much higher than those of the devices based on Pt networks and sputtered CuS films. We believe that such CuS network TCEs with high flexibility, transparency, conductivity and catalytic activity could be widely used in making wearable electronic products.

  9. Selective Light-Induced Patterning of Carbon Nanotube/Silver Nanoparticle Composite To Produce Extremely Flexible Conductive Electrodes.

    Science.gov (United States)

    Kim, Inhyuk; Woo, Kyoohee; Zhong, Zhaoyang; Lee, Eonseok; Kang, Dongwoo; Jeong, Sunho; Choi, Young-Man; Jang, Yunseok; Kwon, Sin; Moon, Jooho

    2017-02-22

    Recently, highly flexible conductive features have been widely demanded for the development of various electronic applications, such as foldable displays, deformable lighting, disposable sensors, and flexible batteries. Herein, we report for the first time a selective photonic sintering-derived, highly reliable patterning approach for creating extremely flexible carbon nanotube (CNT)/silver nanoparticle (Ag NP) composite electrodes that can tolerate severe bending (20 000 cycles at a bending radius of 1 mm). The incorporation of CNTs into a Ag NP film can enhance not only the mechanical stability of electrodes but also the photonic-sintering efficiency when the composite is irradiated by intense pulsed light (IPL). Composite electrodes were patterned on various plastic substrates by a three-step process comprising coating, selective IPL irradiation, and wiping. A composite film selectively exposed to IPL could not be easily wiped from the substrate, because interfusion induced strong adhesion to the underlying polymer substrate. In contrast, a nonirradiated film adhered weakly to the substrate and was easily removed, enabling highly flexible patterned electrodes. The potential of our flexible electrode patterns was clearly demonstrated by fabricating a light-emitting diode circuit and a flexible transparent heater with unimpaired functionality under bending, rolling, and folding.

  10. Flexible Thick-Film Electrochemical Sensors: Impact of Mechanical Bending and Stress on the Electrochemical Behavior

    Science.gov (United States)

    Cai, Jiaying; Cizek, Karel; Long, Brenton; McAferty, Kenyon; Campbell, Casey G.; Allee, David R.; Vogt, Bryan D.; La Belle, Jeff; Wang, Joseph

    2009-01-01

    The influence of the mechanical bending, rolling and crimping of flexible screen-printed electrodes upon their electrical properties and electrochemical behavior has been elucidated. Three different flexible plastic substrates, Mylar, polyethylene naphthalate (PEN), and Kapton, have been tested in connection to the printing of graphite ink working electrodes. Our data indicate that flexible printed electrodes can be bent to extremely small radii of curvature and still function well, despite a marginal increase the electrical resistance. Below critical radii of curvature of ~8 mm, full recovery of the electrical resistance occurs upon strain release. The electrochemical response is maintained for sub-mm bending radii and a 180° pinch of the electrode does not lead to device failure. The electrodes appear to be resistant to repeated bending. Such capabilities are demonstrated using model compounds, including ferrocyanide, trinitrotoluene (TNT) and nitronaphthalene (NN). These printed electrodes hold great promise for widespread applications requiring flexible, yet robust non-planar sensing devices. PMID:20160861

  11. Plasticity theory

    CERN Document Server

    Lubliner, Jacob

    2008-01-01

    The aim of Plasticity Theory is to provide a comprehensive introduction to the contemporary state of knowledge in basic plasticity theory and to its applications. It treats several areas not commonly found between the covers of a single book: the physics of plasticity, constitutive theory, dynamic plasticity, large-deformation plasticity, and numerical methods, in addition to a representative survey of problems treated by classical methods, such as elastic-plastic problems, plane plastic flow, and limit analysis; the problem discussed come from areas of interest to mechanical, structural, and

  12. Two-step flash light sintering process for enhanced adhesion between copper complex ion/silane ink and a flexible substrate

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Eun-Beom; Joo, Sung-Jun [Department of Mechanical Convergence Engineering, Hanyang University, Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Ahn, Heejoon [Department of Organic and Nano Engineering, Hanyang University, Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Hak-Sung, E-mail: kima@hanyang.ac.kr [Department of Mechanical Convergence Engineering, Hanyang University, Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Institute of Nano Science and Technology, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2016-03-31

    A copper complex ion ink (including copper nanoparticles, a copper precursor and a silane coupling agent) was synthesized to enhance the adhesion between the copper pattern and a polyimide (PI) substrate. Oxygen plasma treatment was performed on the polyimide substrate to initiate a chemical reaction between the complex ion ink and the polyimide. Then, a two-step flash light sintering method (consisting of preheating and main sintering) was used to sinter the copper complex ion ink. The copper complex ion patterns were characterized as a function of the weight fraction of silane coupling agent using scanning electron microscopy (SEM), a four-point probe method and adhesion testing. In addition, a bending fatigue test was performed to evaluate the reliability of the conductive copper pattern under cyclic bending. The copper pattern fabricated with copper complex ion ink containing 3 wt% silane coupling agent exhibited the highest adhesion level (5B), the lowest resistivity (7.6 μΩ·cm) and a low resistance change (18%) after the bending fatigue test. The two-step sintering method used to enhance the adhesion between the copper complex ion ink and polyimide substrate was also studied using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). - Highlights: • The copper complex ion ink with copper nanoparticles and copper precursor was fabricated. • The copper complex ion ink was sintered by two-step flash light sintering method. • The sintered copper pattern exhibited the highest adhesion level (5B). • The resistivity of sintered copper pattern was 7.6 μΩ·cm.

  13. Direct Write Processing of Multi-micron Thickness Copper Nano-particle Paste on Flexible Substrates with 532 nm Laser Wavelength

    Science.gov (United States)

    Lopez-Espiricueta, Dunia; Fearon, Eamonn; Edwardson, Stuart; Dearden, Geoffrey

    The Laser Assisted Direct Write (LA-DW) method has been implemented in the development of different markets and material processing, recently also used for creating Printed Circuit Boards (PCB) or electrical circuitry. The process consists in the deposition of metallic nano-particle (NP) inks, which are afterwards cured or sintered by laser irradiation, thus creating conductive pathways; advantages are speed, accuracy and the protection of the heat affected zone (HAZ). This research will study the behaviour of the heat dissipation relatively within the Nano-particle Copper paste after being irradiated with 1064 nm and 532 nm wavelengths, research will be developed on different widths and depths deposited onto flat surfaces such as flexible PET. Comparisons to be made between resistivity results obtained from different wavelengths.

  14. Effect of rotating different leaf vegetables with tomato in plastic tunnel on reuse of continuous cropping substrate%轮作叶菜对大棚番茄连作基质重复利用效果的影响

    Institute of Scientific and Technical Information of China (English)

    李威; 孟焕文; 程智慧; 周静; 柴喜荣; 梁静

    2012-01-01

    【Objective】The study was done to compare the effects of rotating different kinds of leaf vegetables in continuous cropping organic substrate on reducing or eliminating the continuous cropping obstacle of tomato under plastic tunnel cultivation.【Method】Green garlic,no-heading Chinese cabbage and leaf lettuce were respectively planted in the substrate with two season continuous production of tomato during winter fallow season under plastic tunnel.Tomato was planted as the aftercrop to investigate the effects of leaf vegetable rotation taking winter fallow substrate as CK1,the fresh substrate of the same formula as CK2 and the fresh substrate with peat and perlite as CK3.【Result】Except for the obvious change in EC value for the substrate of continuous cropping treatment,there is little alteration in EC value,pH value,bulk density and total porosity in the substrates of the other treatments before and after crop cultivation.That means those substrates are relatively stable in physical and chemical properties which are all within the optimal range for tomato growing and are appropriate for reuse to grow tomato.The contents of alkali hydrolysable nitrogen,available phosphorus and available potassium in substrate of different treatments are decreased by different degrees after rotating of different leaf vegetables.The plant growth and root vigor of aftercrop tomato during the whole growth period in treatment A and B show significant predominance to CK1 and close to or not significantly different from CK2 and CK3.The yield of tomato in treatment rotated with green garlic shows no significant difference from CK3 but significantly higher than CK2.The effect of rotating no-heading Chinese cabbage is just next to rotating green garlic.However,winter fallow(CK1) presents the lowest yield.As for fruit quality,the contents of soluble sugar,soluble protein,lycopene and sugar-acid ratio are higher in tomato rotated with garlic which show no significant difference

  15. Low-temperature growth and physical investigations of undoped and (In, Co) doped ZnO thin films sprayed on PEI flexible substrate

    Science.gov (United States)

    Ben Ameur, S.; Barhoumi, A.; Mimouni, R.; Amlouk, M.; Guermazi, H.

    2015-08-01

    ZnO thin films were deposited on polymer substrate Polyethyerimide (PEI) at 250 °C by spray pyrolysis technique. The effects of different doping elements (Co and In) on physical properties of ZnO thin films were investigated. Thin film characterizations were carried out using X-ray diffraction technique, UV-Vis-NIR spectroscopy, Photoluminescence (PL) spectroscopy and the contact angle measurement method. XRD measurement showed a successful growth of crystalline films on polymer substrate at low temperature by the spray pyrolysis process. XRD patterns revealed that all films consist of single ZnO phase and were well crystallized with preferential orientation towards (1 0 1) direction. Doping by cobalt has effective role in the enhancement of the crystalline quality, increases in the band gap according to Burstein Moss effect. Doping with indium leads rather to the decrease of both crystallinity and optical band gap energy value. Photoluminescence of the films showed UV emission (NBE) and visible emission related to defects. The contact angles were measured to study the effect of various doping elements on the hydrophobicity of the film depending on surface roughness. Results showed strong dependence on the doping element. In fact, doping with cobalt element increases the roughness of ZnO films and reinforces the surface from hydrophilic to hydrophobic (θ > 90°).

  16. A high-performance and low cost SERS substrate of plasmonic nanopillars on plastic film fabricated by nanoimprint lithography with AAO template

    Science.gov (United States)

    Liu, Long; Zhang, Qian; Lu, Yuanshen; Du, Wei; Li, Bin; Cui, Yushuang; Yuan, Changsheng; Zhan, Peng; Ge, Haixiong; Wang, Zhenling; Chen, Yanfeng

    2017-06-01

    As a powerful spectroscopy technique, surface-enhanced Raman scattering (SERS) can provide non-destructive and sensitive characterization down to a single molecular level. Aiming to the main challenges of high-performance SERS-active substrates for their real-world applications involving the ultra-sensitive and reproducible signals detection and signal uniformity with large-area, herein, a facile and reliable strategy based on combination of thermal imprinting polycarbonate (PC) film with porous anodic aluminum oxide (AAO) mold and E-beam evaporation of gold is provided to fabricate a high-quality SERS-active substrate consisting of ultra-dense hot-spots with large-area uniformity. Two kinds of sub-10 nm gaps were obtained, including the nanogaps between the neighboring gold coated PC-nanopillars and those between gold on the top of the nanopillars and that on the base, which actually build up a three-dimensional (3D) hot-spot network for high-performance SERS detection. The effect of structural parameters on SERS enhancement was investigated numerically and experimentally, and by optimizing the structural parameters, a remarkable average SERS enhancement factor up to of 1.4×108 is achieved and it shows an excellent reproducibility with a relative standard deviation of 18%, which allows for enhanced practicability in the application of quantitative biochemical detection.

  17. Low temperature silicon nitride by hot wire chemical vapour deposition for the use in impermeable thin film encapsulation on flexible substrates.

    Science.gov (United States)

    Spee, D A; van der Werf, C H M; Rath, J K; Schropp, R E I

    2011-09-01

    High quality non porous silicon nitride layers were deposited by hot wire chemical vapour deposition at substrate temperatures lower than 110 degrees C. The layer properties were investigated using FTIR, reflection/transmission measurements and 1:6 buffered HF etching rate. A Si-H peak position of 2180 cm(-1) in the Fourier transform infrared absorption spectrum indicates a N/Si ratio around 1.2. Together with a refractive index of 1.97 at a wavelength of 632 nm and an extinction coefficient of 0.002 at 400 nm, this suggests that a transparent high density silicon nitride material has been made below 110 degrees C, which is compatible with polymer films and is expected to have a high impermeability. To confirm the compatibility with polymer films a silicon nitride layer was deposited on poly(glycidyl methacrylate) made by initiated chemical vapour deposition, resulting in a highly transparent double layer.

  18. FLEXIBLE GEIGER COUNTER

    Science.gov (United States)

    Richter, H.G.; Gillespie, A.S. Jr.

    1963-11-12

    A flexible Geiger counter constructed from materials composed of vinyl chloride polymerized with plasticizers or co-polymers is presented. The counter can be made either by attaching short segments of corrugated plastic sleeving together, or by starting with a length of vacuum cleaner hose composed of the above materials. The anode is maintained substantially axial Within the sleeving or hose during tube flexing by means of polystyrene spacer disks or an easily assembled polyethylene flexible cage assembly. The cathode is a wire spiraled on the outside of the counter. The sleeving or hose is fitted with glass end-pieces or any other good insulator to maintain the anode wire taut and to admit a counting gas mixture into the counter. Having the cathode wire on the outside of the counter substantially eliminates the objectional sheath effect of prior counters and permits counting rates up to 300,000 counts per minute. (AEC)

  19. Flexible supercapacitors

    Institute of Scientific and Technical Information of China (English)

    Shan Shi; Chengjun Xu; Cheng Yang; Jia Li; Hongda Du; Baohua Li; Feiyu Kang

    2013-01-01

    Flexible supercapacitors show a great potential for applications in wearable,miniaturized,portable,largescale transparent and flexible consumer electronics due to their significant,inherent advantages,such as being flexible,lightweight,low cost and environmentally friendly in comparison with the current energy storage devices.In this report,recent progress on flexible supercapacitors,flexible electrodes and electrolytes is reviewed.In addition,the future challenges and opportunities are discussed.

  20. Reversibly Bistable Flexible Electronics

    KAUST Repository

    Alfaraj, Nasir

    2015-05-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent. While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin and foldable ones without compromising long-term performance and reliability. In this work, we report on the fabrication and characterization of reversibly bistable flexible electronic switches that utilize flexible n-channel metal-oxide-semiconductor field-effect transistors. The transistors are fabricated initially on rigid (100) silicon substrates before they are peeled off. They can be used to control flexible batches of light-emitting diodes, demonstrating both the relative ease of scaling at minimum cost and maximum reliability and the feasibility of integration. The peeled-off silicon fabric is about 25 µm thick. The fabricated devices are transferred to a reversibly bistable flexible platform through which, for example, a flexible smartphone can be wrapped around a user’s wrist and can also be set back to its original mechanical position. Buckling and cyclic bending of such host platforms brings a completely new dimension to the development of flexible electronics, especially rollable displays.

  1. Ultrathin flexible memory devices based on organic ferroelectric transistors

    Science.gov (United States)

    Sugano, Ryo; Hirai, Yoshinori; Tashiro, Tomoya; Sekine, Tomohito; Fukuda, Kenjiro; Kumaki, Daisuke; Domingues dos Santos, Fabrice; Miyabo, Atsushi; Tokito, Shizuo

    2016-10-01

    Here, we demonstrate ultrathin, flexible nonvolatile memory devices with excellent durability under compressive strain. Ferroelectric-gate field-effect transistors (FeFETs) employing organic semiconductor and polymer ferroelectric layers are fabricated on a 1-µm-thick plastic film substrate. The FeFETs are characterized by measuring their transfer characteristics, programming time, and data retention time. The data retention time is almost unchanged even when a 50% compressive strain is applied to the devices. To clarify the origin of the excellent durability of the devices against compressive strain, an intermediate plane is calculated. From the calculation result, the intermediate plane is placed close to the channel region of the FeFETs. The high flexibility of the ferroelectric polymer and ultrathin device structure contributes to achieving a bending radius of 0.8 µm without the degradation of memory characteristics.

  2. Ultrathin and lightweight organic solar cells with high flexibility

    Science.gov (United States)

    Kaltenbrunner, Martin; White, Matthew S.; Głowacki, Eric D.; Sekitani, Tsuyoshi; Someya, Takao; Sariciftci, Niyazi Serdar; Bauer, Siegfried

    2012-01-01

    Application-specific requirements for future lighting, displays and photovoltaics will include large-area, low-weight and mechanical resilience for dual-purpose uses such as electronic skin, textiles and surface conforming foils. Here we demonstrate polymer-based photovoltaic devices on plastic foil substrates less than 2 μm thick, with equal power conversion efficiency to their glass-based counterparts. They can reversibly withstand extreme mechanical deformation and have unprecedented solar cell-specific weight. Instead of a single bend, we form a random network of folds within the device area. The processing methods are standard, so the same weight and flexibility should be achievable in light emitting diodes, capacitors and transistors to fully realize ultrathin organic electronics. These ultrathin organic solar cells are over ten times thinner, lighter and more flexible than any other solar cell of any technology to date. PMID:22473014

  3. Specifics and Challenges to Flexible Organic Light-Emitting Devices

    Directory of Open Access Journals (Sweden)

    Mariya Aleksandrova

    2016-01-01

    Full Text Available Several recent developments in material science and deposition methods for flexible organic light-emitting devices (OLEDs are surveyed. The commonly used plastic substrates are compared, according to their mechanical, optical, thermal, and chemical properties. Multilayer electrode structures, used as transparent electrodes, replacing conventional indium tin oxide (ITO are presented and data about their conductivity, transparency, and bending ability are provided. Attention is paid to some of the most popular industrial processes for flexible OLEDs manufacturing, such as roll-to-roll printing, inkjet printing, and screen printing. Main specifics and challenges, related to the foils reliability, mechanical stability of the transparent electrodes, and deposition and patterning of organic emissive films, are discussed.

  4. Nanomechanics of hard films on compliant substrates.

    Energy Technology Data Exchange (ETDEWEB)

    Reedy, Earl David, Jr. (Sandia National Laboratories, Albuquerque, NM); Emerson, John Allen (Sandia National Laboratories, Albuquerque, NM); Bahr, David F. (Washington State University, Pullman, WA); Moody, Neville Reid; Zhou, Xiao Wang; Hales, Lucas (University of Minnesota, Minneapolis, MN); Adams, David Price (Sandia National Laboratories, Albuquerque, NM); Yeager,John (Washington State University, Pullman, WA); Nyugen, Thao D. (Johns Hopkins University, Baltimore, MD); Corona, Edmundo (Sandia National Laboratories, Albuquerque, NM); Kennedy, Marian S. (Clemson University, Clemson, SC); Cordill, Megan J. (Erich Schmid Institute, Leoben, Austria)

    2009-09-01

    Development of flexible thin film systems for biomedical, homeland security and environmental sensing applications has increased dramatically in recent years [1,2,3,4]. These systems typically combine traditional semiconductor technology with new flexible substrates, allowing for both the high electron mobility of semiconductors and the flexibility of polymers. The devices have the ability to be easily integrated into components and show promise for advanced design concepts, ranging from innovative microelectronics to MEMS and NEMS devices. These devices often contain layers of thin polymer, ceramic and metallic films where differing properties can lead to large residual stresses [5]. As long as the films remain substrate-bonded, they may deform far beyond their freestanding counterpart. Once debonded, substrate constraint disappears leading to film failure where compressive stresses can lead to wrinkling, delamination, and buckling [6,7,8] while tensile stresses can lead to film fracture and decohesion [9,10,11]. In all cases, performance depends on film adhesion. Experimentally it is difficult to measure adhesion. It is often studied using tape [12], pull off [13,14,15], and peel tests [16,17]. More recent techniques for measuring adhesion include scratch testing [18,19,20,21], four point bending [22,23,24], indentation [25,26,27], spontaneous blisters [28,29] and stressed overlayers [7,26,30,31,32,33]. Nevertheless, sample design and test techniques must be tailored for each system. There is a large body of elastic thin film fracture and elastic contact mechanics solutions for elastic films on rigid substrates in the published literature [5,7,34,35,36]. More recent work has extended these solutions to films on compliant substrates and show that increasing compliance markedly changes fracture energies compared with rigid elastic solution results [37,38]. However, the introduction of inelastic substrate response significantly complicates the problem [10,39,40]. As

  5. Plastic Jellyfish.

    Science.gov (United States)

    Moseley, Christine

    2000-01-01

    Presents an environmental science activity designed to enhance students' awareness of the hazards of plastic waste for wildlife in aquatic environments. Discusses how students can take steps to reduce the effects of plastic waste. (WRM)

  6. Magnetic domain-wall motion study under an electric field in a Finemet{sup ®} thin film on flexible substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Ngo Thi [Laboratoire des Sciences des Procédés et des Matériaux, CNRS-Université Paris XIII, 93430 Villetaneuse (France); Mercone, Silvana, E-mail: silvana.mercone@univ-paris13.fr [Laboratoire des Sciences des Procédés et des Matériaux, CNRS-Université Paris XIII, 93430 Villetaneuse (France); Moulin, Johan [Institut d' Electronique Fondamentale, UMR 8622 Université Paris Sud/CNRS, Orsay (France); Bahoui, Anouar El; Faurie, Damien; Zighem, Fatih; Belmeguenai, Mohamed; Haddadi, Halim [Laboratoire des Sciences des Procédés et des Matériaux, CNRS-Université Paris XIII, 93430 Villetaneuse (France)

    2015-01-01

    We study the influence of applied in-plane elastic strains on the static magnetic configuration of a 530 nm magnetostrictive FeCuNbSiB (Finemet{sup ®}) thin film. The in-plane strains are induced via the application of a voltage to a piezoelectric actuator on which the film/substrate system was glued. A quantitative characterization of the voltage dependence of the induced-strain at the surface of the film was performed using a digital image correlation technique. Magnetic Force Microscopy (MFM) images at remanence (H=0 Oe and U=0 V) clearly reveal the presence of weak stripe domains. The effect of the voltage-induced strain shows the existence of a voltage threshold value for the strike configuration break. For a maximum strain of ε{sub XX}∼0.5×10{sup −3} we succeed in destabilizing the stripes configuration helping the setting up of a complete homogeneous magnetic pattern. - Highlights: • Elastic strain effect on the magnetic domain structure of a Finemet/Kapton is investigated. • External loading is applied thanks to a piezo-actuator on which the sample is glued. • The amount of strains was measured by the Digital Image Correlation technique. • Magnetic Force Microscopy showed high mobility of magnetic stripes domains. • Bending, curving and branching of domains go into maze-like pattern.

  7. Structure of the Bacillus anthracis Sortase A Enzyme Bound to Its Sorting Signal: A FLEXIBLE AMINO-TERMINAL APPENDAGE MODULATES SUBSTRATE ACCESS.

    Science.gov (United States)

    Chan, Albert H; Yi, Sung Wook; Terwilliger, Austen L; Maresso, Anthony W; Jung, Michael E; Clubb, Robert T

    2015-10-16

    The endospore forming bacterium Bacillus anthracis causes lethal anthrax disease in humans and animals. The ability of this pathogen to replicate within macrophages is dependent upon the display of bacterial surface proteins attached to the cell wall by the B. anthracis Sortase A ((Ba)SrtA) enzyme. Previously, we discovered that the class A (Ba)SrtA sortase contains a unique N-terminal appendage that wraps around the body of the protein to contact the active site of the enzyme. To gain insight into its function, we determined the NMR structure of (Ba)SrtA bound to a LPXTG sorting signal analog. The structure, combined with dynamics, kinetics, and whole cell protein display data suggest that the N terminus modulates substrate access to the enzyme. We propose that it may increase the efficiency of protein display by reducing the unproductive hydrolytic cleavage of enzyme-protein covalent intermediates that form during the cell wall anchoring reaction. Notably, a key active site loop (β7/β8 loop) undergoes a disordered to ordered transition upon binding the sorting signal, potentially facilitating recognition of lipid II.

  8. Dynamic learning and memory, synaptic plasticity and neurogenesis: An update

    Directory of Open Access Journals (Sweden)

    Ales eStuchlik

    2014-04-01

    Full Text Available Mammalian memory is the result of the interaction of millions of neurons in the brain and their coordinated activity. Candidate mechanisms for memory are synaptic plasticity changes, such as long-term potentiation (LTP. LTP is essentially an electrophysiological phenomenon manifested in hours-lasting increase on postsynaptic potentials after synapse tetanization. It is thought to ensure long-term changes in synaptic efficacy in distributed networks, leading to persistent changes in the behavioral patterns, actions and choices, which are often interpreted as the retention of information, i.e., memory. Interestingly, new neurons are born in the mammalian brain and adult hippocampal neurogenesis is proposed to provide a substrate for dynamic and flexible aspects of behavior such as pattern separation, prevention of interference, flexibility of behavior and memory resolution. This work provides a brief review on the memory and involvement of LTP and adult neurogenesis in memory phenomena.

  9. High Performance MgO-barrier Magnetic Tunnel Junctions for Flexible and Wearable Spintronic Applications.

    Science.gov (United States)

    Chen, Jun-Yang; Lau, Yong-Chang; Coey, J M D; Li, Mo; Wang, Jian-Ping

    2017-02-02

    The magnetic tunnel junction (MTJ) using MgO barrier is one of most important building blocks for spintronic devices and has been widely utilized as miniaturized magentic sensors. It could play an important role in wearable medical devices if they can be fabricated on flexible substrates. The required stringent fabrication processes to obtain high quality MgO-barrier MTJs, however, limit its integration with flexible electronics devices. In this work, we have developed a method to fabricate high-performance MgO-barrier MTJs directly onto ultrathin flexible silicon membrane with a thickness of 14 μm and then transfer-and-bond to plastic substrates. Remarkably, such flexible MTJs are fully functional, exhibiting a TMR ratio as high as 190% under bending radii as small as 5 mm. The devices' robustness is manifested by its retained excellent performance and unaltered TMR ratio after over 1000 bending cycles. The demonstrated flexible MgO-barrier MTJs opens the door to integrating high-performance spintronic devices in flexible and wearable electronics devices for a plethora of biomedical sensing applications.

  10. High Performance MgO-barrier Magnetic Tunnel Junctions for Flexible and Wearable Spintronic Applications

    Science.gov (United States)

    Chen, Jun-Yang; Lau, Yong-Chang; Coey, J. M. D.; Li, Mo; Wang, Jian-Ping

    2017-02-01

    The magnetic tunnel junction (MTJ) using MgO barrier is one of most important building blocks for spintronic devices and has been widely utilized as miniaturized magentic sensors. It could play an important role in wearable medical devices if they can be fabricated on flexible substrates. The required stringent fabrication processes to obtain high quality MgO-barrier MTJs, however, limit its integration with flexible electronics devices. In this work, we have developed a method to fabricate high-performance MgO-barrier MTJs directly onto ultrathin flexible silicon membrane with a thickness of 14 μm and then transfer-and-bond to plastic substrates. Remarkably, such flexible MTJs are fully functional, exhibiting a TMR ratio as high as 190% under bending radii as small as 5 mm. The devices‘ robustness is manifested by its retained excellent performance and unaltered TMR ratio after over 1000 bending cycles. The demonstrated flexible MgO-barrier MTJs opens the door to integrating high-performance spintronic devices in flexible and wearable electronics devices for a plethora of biomedical sensing applications.

  11. High Performance MgO-barrier Magnetic Tunnel Junctions for Flexible and Wearable Spintronic Applications

    Science.gov (United States)

    Chen, Jun-Yang; Lau, Yong-Chang; Coey, J. M. D.; Li, Mo; Wang, Jian-Ping

    2017-01-01

    The magnetic tunnel junction (MTJ) using MgO barrier is one of most important building blocks for spintronic devices and has been widely utilized as miniaturized magentic sensors. It could play an important role in wearable medical devices if they can be fabricated on flexible substrates. The required stringent fabrication processes to obtain high quality MgO-barrier MTJs, however, limit its integration with flexible electronics devices. In this work, we have developed a method to fabricate high-performance MgO-barrier MTJs directly onto ultrathin flexible silicon membrane with a thickness of 14 μm and then transfer-and-bond to plastic substrates. Remarkably, such flexible MTJs are fully functional, exhibiting a TMR ratio as high as 190% under bending radii as small as 5 mm. The devices‘ robustness is manifested by its retained excellent performance and unaltered TMR ratio after over 1000 bending cycles. The demonstrated flexible MgO-barrier MTJs opens the door to integrating high-performance spintronic devices in flexible and wearable electronics devices for a plethora of biomedical sensing applications. PMID:28150807

  12. CRESCIMENTO E DESENVOLVIMENTO DA ALFACE (Lactuca sativa L. CONDUZIDA EM ESTUFA PLÁSTICA COM FERTIRRIGAÇÃO EM SUBSTRATOS GROWTH AND DEVELOPMENT OF LETTUCE (Lactuca sativa L. IN A PLASTIC GREENHOUSE WITH FERTIRRIGATION IN SUBSTRATES

    Directory of Open Access Journals (Sweden)

    Luis Aquiles Martins Medeiros

    2001-04-01

    Full Text Available Foram conduzidos dois experimentos, um cultivo no outono e outro no inverno de 1998, em estufa plástica localizada no Departamento de Fitotecnia da Universidade Federal de Santa Maria, com o objetivo de estudar a influência da fertirrigação em substratos no crescimento e desenvolvimento da alface, cultivar Brisa. Os tratamentos, com e sem fertirrigação, foram constituídos pelos substratos húmus de minhoca mais casca de arroz natural (H+CN, húmus de minhoca mais casca de arroz carbonizada (H+CC e solo como testemunha, constituindo um bifatorial 3x2. A fertirrigação foi realizada em função da condutividade elétrica (CE da solução drenada dos substratos. O delineamento experimental utilizado foi de blocos casualizados com quatro repetições. Semanalmente, foram determinados o número de folhas por planta, a massa fresca e seca da parte aérea das plantas e o índice de área foliar. Avaliou-se, ainda, a capacidade de retenção de água (CRa dos substratos isolados e das misturas, antes e após os cultivos. A CRa dos substratos aumentou ao longo dos cultivos enquanto a do solo permaneceu constante. Os substratos irrigados com solução nutritiva proporcionaram maior número de folhas, maior produção de massa fresca e seca da parte aérea e maior índice de área foliar do que quando irrigados apenas com água, sendo que os substratos H+CN e H+CC foram significativamente mais produtivos do que o substrato testemunha em ambos os cultivosIn order to study the effects of fertirrigation in growing substrates on the development of lettuce cultivar Brisa, two essays were conducted, one during the fall of 1998 and the other during the winter, in a plastic greenhouse in the Federal University of Santa Maria. The treatments with and without fertirrigation were constituted by earthworm humus plus rice hulls (H+CN, earthworm humus plus carbonized rice hulls (H+CC and pure soil as check. The fertirrigation timing was established by monitoring

  13. Strategic flexibility

    OpenAIRE

    Kim, KiHyung

    2014-01-01

    A flexible system is defined as one that can change the entity's stance, capability or status reacting to a change of the entity's environment. Flexibility has gathered the attention of academic researchers and industry practitioners as an efficient approach to cope with today's volatile environment. As the environments become more unpredictable and volatile, it is imperative for a flexible system to respond quickly to a change in its circumstance. How much flexibility is embedded into the sy...

  14. Novel Flexible Plastic-Based Solar Cells

    Science.gov (United States)

    2012-10-19

    different types of solar cells: 1) Synthesis of hole transporting low band gap polymers, development of ligand exchange in a nanocomposite, and...a) Energy band diagram of the device structure, (b) The SEM image of the cross section of the devices, (c) I-V characteristics of the TiO2 -PbS... band gap polymers have been investigated to exhibit PCE as high as 8~9% with a PCBM derivative (PC71BM). As a replacement of a typical organic

  15. 基于柔性衬底的ZnO葡萄糖酶电极制备及特性%Fabrication and Characteristic of ZnO Glucose Oxidase Enzyme Electrode Based on Flexible Substrate

    Institute of Scientific and Technical Information of China (English)

    李金华; 李静; 方铉; 王晓华; 魏志鹏

    2012-01-01

    通过水热法在长有ZnO籽晶层的柔性聚酰亚胺(PI)衬底上生长了整齐的ZnO纳米棒,ZnO纳米棒的晶体结构和表面形貌通过X射线衍射(XRD)、扫描电子显微镜(SEM)等进行表征.通过静电吸附方式,将葡萄糖氧化酶(GOx)固定在其表面.分别对GOx及修饰前后的ZnO纳米棒进行了紫外-可见光谱表征,发现修饰后存在ZnO的吸收峰和GOx的特征吸收峰,表明GOx固定在ZnO表面.通过对修饰样品进行傅里叶变换红外(FTIR)光谱测试发现了与GOx相关的吸收峰,这进一步表明GO×仍保持生物活性,最后在循环伏安曲线的测试中,这种在柔性衬底上制备的生物酶电极表现出非常灵敏的电流响应,为制备柔性葡萄糖生物传感器奠定了实验基础.%Well-aligned ZnO nanorods (NRs) were grown on the ZnO seed layer of a polyimide (PI)coated flexible substrate using the hydrothermal method and used as a support matrix for the immobilization of glucose oxidase (GOx).The crystal structures and surface morphologies of the so-formed ZnO nanorods were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM).GOx was immobilized on the surfaces of ZnO nanorods using electrostatic adsorption.Both the GOx and modified ZnO nanorods were characterized by UV-visible spectroscopy,and the absorption peaks of ZnO and GOx can be detected.Fourier transform infrared (FTIR) spectroscopy were used to characterize the chemical structure of the glucose oxide,which still maintained its biological activity.This study provides an experiment basis for the preparation of flexible glucose biosensors owing to the flexibility of the enzyme electrode,which showed a sensitive current response when tested by cyclic voltammetry.

  16. Flexible Software for Flexible Scheduling

    Science.gov (United States)

    Economou, Frossie; Jenness, Tim; Tilanus, Remo P. J.; Hirst, Paul; Adamson, Andy J.; Rippa, Mathew; Delorey, Kynan K.; Isaak, Kate G.

    The JAC Observation Management Project (OMP) provides software for the James Clerk Maxwell (JCMT) and the United Kingdom Infrared (UKIRT) telescopes that manages the life-cycle of flexibly scheduled observations. Its aim is to increase observatory efficiency under flexible (queue) scheduled observing, without depriving the principal investigator (PI) of the flexibility associated with classical scheduling.

  17. Screen printed passive components for flexible power electronics.

    Science.gov (United States)

    Ostfeld, Aminy E; Deckman, Igal; Gaikwad, Abhinav M; Lochner, Claire M; Arias, Ana C

    2015-10-30

    Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components-inductors, capacitors, and resistors-perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application.

  18. Screen printed passive components for flexible power electronics

    Science.gov (United States)

    Ostfeld, Aminy E.; Deckman, Igal; Gaikwad, Abhinav M.; Lochner, Claire M.; Arias, Ana C.

    2015-10-01

    Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components—inductors, capacitors, and resistors—perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application.

  19. TCO/metal/TCO structures for energy and flexible electronics

    Energy Technology Data Exchange (ETDEWEB)

    Guillen, C., E-mail: c.guillen@ciemat.es; Herrero, J.

    2011-10-31

    There is increasing attention paid to improving transparent conductive electrodes for applications in large area photovoltaic devices and displays that are being developed for energy and electronics. To date, transparent and conductive oxides (TCO) based on In{sub 2}O{sub 3}, ZnO, or SnO{sub 2} are commonly used, but advanced devices require new electrodes with lower resistivities than previously achieved and with optical properties superior to those of the present generation. TCO/metal/TCO multilayer structures have emerged as an interesting alternative because they provide optical and electrical characteristics globally superior to those attainable with a single-layer TCO or metal electrode and can be deposited at low temperatures onto inexpensive plastic substrates. Indeed, the fabrication of thin film devices on flexible substrates has substantial interest for application to lightweight products and implementation of roll-to-roll deposition processes that can significantly reduce production costs. In this sense, organic electronics that require low deposition temperatures have the best chance to be the first transferred from conventional glass to inexpensive plastic substrates. The present critical review summarizes current TCO/metal/TCO research results, first analyzed for materials and thickness selection as a function of the optical transmittance and electrical resistance parameters, and then analyzed according to other important properties such as mechanical reliability and thermal and humidity stability. The review concludes with a brief discussion of the results obtained for TCO/metal/TCO structures applied as electrodes in several organic electronic devices.

  20. Flexible all-polymer waveguide for low threshold amplified spontaneous emission

    Science.gov (United States)

    Smirnov, José R. Castro; Zhang, Qi; Wannemacher, Reinhold; Wu, Longfei; Casado, Santiago; Xia, Ruidong; Rodriguez, Isabel; Cabanillas-González, Juan

    2016-09-01

    The fabrication of all polymer optical waveguides, based on a highly fluorescent conjugated polymer (CP) poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) and a mechanically flexible and biodegradable polymer, cellulose acetate (CA), is reported. The replication by hot embossing of patterned surfaces in CA substrates, onto which high quality F8BT films can be easily processed by spin coating, is exploited to produce an entirely plastic device that exhibits low optical loss and low threshold for amplified spontaneous emission (ASE). As a result, highly transparent and flexible waveguides are obtained, with excellent optical properties that remain unaltered after bending, allowing them to be adapted in various flexible photonic devices.