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1

Nitrogen-doped graphene as transparent counter electrode for efficient dye-sensitized solar cells  

SciTech Connect

Graphical abstract: Display Omitted Highlights: ? NG sheets are prepared through a hydrothermal reduction of graphite oxide. ? The transparent NG counter electrodes of DSCs are fabricated at room temperature. ? Transparent NG electrode exhibits excellent catalytic activity for the reduction of I{sub 3}{sup ?}. ? The DSC with NG electrode achieves a comparable efficiency to that of the Pt-based cell. ? The efficiency of rear illumination is about 85% that of front illumination. -- Abstract: Nitrogen-doped graphene sheets are prepared through a hydrothermal reduction of graphite oxide in the presence of ammonia and applied to fabricate the transparent counter electrode of dye-sensitized solar cells. The atomic percentage of nitrogen in doped graphene sample is about 2.5%, and the nitrogen bonds display pyridine and pyrrole-like configurations. Cyclic voltammetry studies demonstrate a much higher electrocatalytic activity toward I{sup ?}/I{sub 3}{sup ?} redox reaction for nitrogen-doped graphene, as compared with pristine graphene. The dye-sensitized solar cell with this transparent nitrogen-doped graphene counter electrode shows conversion efficiencies of 6.12% and 5.23% corresponding to front-side and rear-side illumination, respectively. Meanwhile, the cell with a Pt counter electrode shows a conversion efficiency of 6.97% under the same experimental condition. These promising results highlight the potential application of nitrogen-doped graphene in cost-effective, transparent dye-sensitized solar cells.

Wang, Guiqiang, E-mail: wgqiang123@163.com [School of Chemical Engineering, Shandong University of Technology, Zibo 255049 (China)] [School of Chemical Engineering, Shandong University of Technology, Zibo 255049 (China); Fang, Yanyan; Lin, Yuan [Institute of Chemistry, Chinese Academy of Science, Beijing 100080 (China)] [Institute of Chemistry, Chinese Academy of Science, Beijing 100080 (China); Xing, Wei; Zhuo, Shuping [School of Chemical Engineering, Shandong University of Technology, Zibo 255049 (China)] [School of Chemical Engineering, Shandong University of Technology, Zibo 255049 (China)

2012-12-15

2

Graphene as transparent conducting electrodes in organic photovoltaics: studies in graphene morphology, hole transporting layers, and counter electrodes.  

PubMed

In this work, organic photovoltaics (OPV) with graphene electrodes are constructed where the effect of graphene morphology, hole transporting layers (HTL), and counter electrodes are presented. Instead of the conventional poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) PEDOT:PSS HTL, an alternative transition metal oxide HTL (molybdenum oxide (MoO(3))) is investigated to address the issue of surface immiscibility between graphene and PEDOT:PSS. Graphene films considered here are synthesized via low-pressure chemical vapor deposition (LPCVD) using a copper catalyst and experimental issues concerning the transfer of synthesized graphene onto the substrates of OPV are discussed. The morphology of the graphene electrode and HTL wettability on the graphene surface are shown to play important roles in the successful integration of graphene films into the OPV devices. The effect of various cathodes on the device performance is also studied. These factors (i.e., suitable HTL, graphene surface morphology and residues, and the choice of well-matching counter electrodes) will provide better understanding in utilizing graphene films as transparent conducting electrodes in future solar cell applications. PMID:22107487

Park, Hyesung; Brown, Patrick R; Bulovi?, Vladimir; Kong, Jing

2012-01-11

3

Metal sulfide counter electrodes for dye-sensitized solar cells: A balanced strategy for optical transparency and electrochemical activity  

NASA Astrophysics Data System (ADS)

Dye-sensitized solar cells (DSSCs) have obtained exciting progress in improving energy conversion efficiency and cutting material cost in recent years. It is found that many kinds of inorganic compounds have promising potential to replace platinum as counter electrode materials for DSSCs. Actually, to a thin film electrode, preparation of the thin film is the same important as choice of active materials, because quality of the films has a direct effect on electrochemical and optical performance of the final counter electrodes. In this paper, a general strategy is developed to prepare transparent and high-efficient metal sulfide counter electrodes. In the route, the Group VIIIB metal sulfides are formed as compact, homogenous and stable films on fluorine-doped tin oxide conductive glass from a precursor organic solution by spin coating, and the film thickness can be readily converted to reach the balance between optical transparency and electrochemical activity. Among the Group VIIIB metal sulfides, the nickel sulfide film with the thickness of 100 nm shows the high transparency and energy conversion efficiency of 7.37%, higher than that of the DSSC using platinum electrode. The results provide a new and facile alternative to prepare high-efficient and transparent sulfide counter electrodes for DSSCs.

Song, J.; Li, G. R.; Wu, C. Y.; Gao, X. P.

2014-11-01

4

Transparent bifacial dye-sensitized solar cells based on organic counter electrodes and iodine-free electrolyte  

NASA Astrophysics Data System (ADS)

In this study, a novel bifacially active transparent dye-sensitized solar cell (DSSCs) assembled with a transparent poly(3,4-ethylenedioxythiophene) (PEDOT) counter electrode and a colorless iodine-free polymer gel (IFPG) electrolyte was developed. The IFPG electrolyte was prepared by employing an ionic liquid (1,2-dimethyl-3-propylinmidazolium iodide, DMPII) as the charge transfer intermediate and a polymer composite as the gelator without the addition of iodine, exhibiting high conductivity and non-absorption characters. PEDOT electrodes were prepared via a facile electro-polymerization method. By controlling the amount of polymerization charge capacity, we optimized the PEDOT electrodes with high transparency and a favorable activity for catalyzing the IFPG electrolyte. The bifacial DSSCs device fabricated by this kind of transparent PEDOT electrode and colorless IFPG electrolyte showed a power conversion efficiency (PCE) of 6.35% and 4.98% at 100 mW cm-2 AM1.5 illumination corresponding to front- and rear-side illumination. It is notable that the PCE under rear-side illumination approaches 80% that of front-side illumination. Moreover, the device shows excellent stability as confirmed by aging test. These promising results highlight the enormous potential of this transparent PEDOT CE and colorless IFPG electrolyte in scaling up and commercialization of low cost and effective bifacial DSSCs.

Ku, Zhiliang; Rong, Yaoguang; Han, Hongwei

2013-10-01

5

MoS2 atomic layers with artificial active edge sites as transparent counter electrodes for improved performance of dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

A novel MoS2 transparent counter electrode for dye-sensitized solar cells is reported. In order to enhance the catalytic activity of the electrode, active edge sites are created artificially by patterning holes on MoS2 atomic layers. Electrochemical analysis shows that the electrochemical activity is significantly improved after the patterning of holes. The photon-to-electron efficiency of the dye-sensitized solar cells based on MoS2 atomic layer counter electrodes is increased remarkably from 2% to 5.8% after the hole patterning.

Zhang, Jing; Najmaei, Sina; Lin, Hong; Lou, Jun

2014-04-01

6

MoS2 atomic layers with artificial active edge sites as transparent counter electrodes for improved performance of dye-sensitized solar cells.  

PubMed

A novel MoS2 transparent counter electrode for dye-sensitized solar cells is reported. In order to enhance the catalytic activity of the electrode, active edge sites are created artificially by patterning holes on MoS2 atomic layers. Electrochemical analysis shows that the electrochemical activity is significantly improved after the patterning of holes. The photon-to-electron efficiency of the dye-sensitized solar cells based on MoS2 atomic layer counter electrodes is increased remarkably from 2% to 5.8% after the hole patterning. PMID:24695461

Zhang, Jing; Najmaei, Sina; Lin, Hong; Lou, Jun

2014-04-24

7

Transparent gold nanowire electrodes  

Microsoft Academic Search

Transparent electrodes are used to provide electrical contacts to the active layers of opto-electronic devices such as organic light emitting diodes, flat panel displays and solar cells. These electrodes should possess high optical transparency and low sheet resistance. Traditionally, tin doped indium oxide (ITO) is used for this purpose. Unfortunately, there is increasing concern over the availability of indium leading

Mark C. Rosamond; Andrew J. Gallant; Joe J. Atherton; Michael C. Petty; Oleg Kolosov; Dagou A. Zeze

2011-01-01

8

Transparent metal electrodes  

Microsoft Academic Search

A crucial challenge in the optoelectronics industry is the realization of cheap and reliable transparent electrodes, i.e. films that permit to bring electrical current or potentials in proximity of optically active regions without significant loss of optical energy. The state of the art solution lies in large band gap semiconductors heavily doped with metals, known as transparent conductive oxides (TCOs),

D. S. Ghosh; L. Martinez; V. Pruneri

2009-01-01

9

Highly Transparent and Efficient Counter Electrode Using SiO2/PEDOT-PSS Composite for Bifacial Dye-Sensitized Solar Cells.  

PubMed

A highly transparent and efficient counter electrode was facilely fabricated using SiO2/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) inorganic/organic composite and used in bifacial dye-sensitized solar cells (DSCs). The optical properties of SiO2/PEDOT-PSS electrode can be tailored by the blending amount of SiO2 and film thickness, and the incorporation of SiO2 in PEDOT-PSS provides better transmission in the long wavelength range. Meanwhile, the SiO2/PEDOT-PSS counter electrode shows a better electrochemical catalytic activity than PEDOT-PSS electrode for triiodide reduction, and the role of SiO2 in the catalytic process is investigated. The bifacial DSC with SiO2/PEDOT-PSS counter electrode achieves a high power conversion efficiency (PCE) of 4.61% under rear-side irradiation, which is about 83% of that obtained under front-side irradiation. Furthermore, the PCE of bifacial DSC can be significantly increased by adding a reflector to achieve bifacial irradiation, which is 39% higher than that under conventional front-side irradiation. PMID:24802383

Song, Dandan; Li, Meicheng; Li, Yingfeng; Zhao, Xing; Jiang, Bing; Jiang, Yongjian

2014-05-28

10

A platinum counter electrode with high electrochemical activity and high transparency for dye-sensitized solar cells  

Microsoft Academic Search

Ultra-thin platinum films were deposited on indium tin oxide (ITO) substrates in a sputtering process and used as counter electrodes of dye-sensitized solar cells. The nano-structured Pt film not only has a high transmittance (75%), but also has a lower charge-transfer resistance compared with that of thick Pt films. Under front-side illumination, the synergistic effects of the nano-structured Pt film

Yuh-Lang Lee; Ching-Lun Chen; Lai-Wan Chong; Chien-Heng Chen; Yung-Fang Liu; Ching-Fa Chi

2010-01-01

11

Design of an organic redox mediator and optimization of an organic counter electrode for efficient transparent bifacial dye-sensitized solar cells.  

PubMed

A new thiolate/disulfide mediator was designed and synthesized by employing DFT calculations as a guide. It possesses high transparency to visible light, a very attractive feature for bifacially active transparent DSCs that require a highly transparent counter electrode (CE). Compared to the reported and most promising thiolate/disulfide mediator T(-)/T(2), this new analogous mediator produced a major enhancement in open circuit potential (V(OC)) by about 40 mV and correspondingly a higher power conversion efficiency (?) for DSCs. Furthermore, a highly uniform and transparent (transmittance > 91%) poly(3,4-ethylenedioxythiophene) (PEDOT(BE)) CE was prepared and could efficiently catalyze the reduction of the disulfide. Based on the novel transparent redox couple and PEDOT(BE) CE, a new type of iodine-free and Pt-free transparent bifacial DSC was successfully fabricated. This new bifacial device could not only yield a promising front-illuminated ? of 6.07%, but also produce an attractive ? as high as 4.35% for rear-side irradiation, which exceeds the rear-illuminated ? of 3.93% achieved for the same type of device, employing the dark-colored I(-)/I(3)(-) electrolyte. PMID:23010982

Li, Xiong; Ku, Zhiliang; Rong, Yaoguang; Liu, Guanghui; Liu, Linfeng; Liu, Tongfa; Hu, Min; Yang, Ying; Wang, Heng; Xu, Mi; Xiang, Peng; Han, Hongwei

2012-11-01

12

Transparent conducting oxide semiconductors for transparent electrodes  

Microsoft Academic Search

The present status and prospects for further development of polycrystalline or amorphous transparent conducting oxide (TCO) semiconductors used for practical thin-film transparent electrode applications are presented in this paper. The important TCO semiconductors are impurity-doped ZnO, In2O3 and SnO2 as well as multicomponent oxides consisting of combinations of ZnO, In2O3 and SnO2, including some ternary compounds existing in their systems.

Tadatsugu Minami

2005-01-01

13

Transparent metal oxide electrode CID imager  

Microsoft Academic Search

The use of metal oxide transparent conductive electrodes in a charge-injection device (CID) imaging array has resulted in a quantum efficiency of approximately 70 percent, uniform throughout the visible, with useful array response out to 3500 Å. The advantages of using highly transparent metal oxide electrodes for the fabrication of frontside illuminated arrays is described. A new high density CID

DALE M. BROWN; MARIO GHEZZO; MARVIN GARFINKEL

1976-01-01

14

Optical impedance transformer for transparent conducting electrodes.  

PubMed

A fundamental limitation of transparent conducting electrode design is thought to be the trade-off between photonic and electronic performances. The photonic transmission property of a transparent conducting electrode, however, is not intrinsic but depends critically on the electromagnetic environment where the electrode is located. We develop the concept of optical impedance transformation, and use this concept to design nanophotonic structures that provide broadband and omnidirectional reduction of optical loss in an ultrathin transparent conducting electrode, without compromising its electrical performance. PMID:24773302

Wang, Ken Xingze; Piper, Jessica R; Fan, Shanhui

2014-05-14

15

Polyaniline electrochromic devices with transparent graphene electrodes  

Microsoft Academic Search

Transparent, conductive and uniform graphene films have been prepared and used as electrodes of the electrochromic devices of polyaniline. Polyaniline films on both graphene and the widely used indium tin oxide (ITO) electrodes showed similar electrochemical and spectroelectrochemical properties. However, graphene electrodes exhibited much higher electrochemical stability than ITO in aqueous acidic electrolytes. The performances of the electrochromic devices with

Lu Zhao; Liang Zhao; Yuxi Xu; Tengfei Qiu; Linjie Zhi; Gaoquan Shi

2009-01-01

16

Carbon Nanotubes as Counter Electrodes for Gratzel Solar Cells  

NASA Astrophysics Data System (ADS)

The role of interfaces is very critical for solar cell devices which use nanostructured materials. Dye Sensitized Solar Cells (DSSC) are devices which parts are interfacial in character and physico --chemical processes occur at the interface of two distinct media. DSSC are of great interest due to combination of their high efficiency and relatively low cost. An effective counterelectrode with high electrochemical activity is an important component of DSSC to enhance its practical utility. Presently used Pt coated ITO counterelectrode can not be applied in flexible DSSC architectures, while there is a growing need for flexible anodes which are transparent and have desired interface characteristics. In this work in order to search for such materials for counter electrode in dye sensitized solar cells, newly developed strong and transparent and modified carbon nanotube sheets [1] are used in interfacial counter electrode. To increase the electrochemical activity of the anode the CNT sheets are coated with highly conductive SWCNT and compared with pure multiwall CNT sheets. We show that the transparent sheets of SWCNT/MWCNT perform as a flexible anode and as electrochemical catalyst and also can be used in tandems of dye sensitized solar cells as transparent charge recombination or interconnect layers. [1] M. Zhang, S.Fang, A.Zakhidov, S.B.Lee, A.Aliev et.al., Science, 309,(2005) 1215

Shodive, Hasan; Aliev, Ali; Zhang, Mei; Lee, Sergey; Baughman, Ray; Zakhidov, Anvar

2006-03-01

17

Graphene versus oxides for transparent electrode applications  

NASA Astrophysics Data System (ADS)

Due to their combination of good electrical conductivity and optical transparency, Transparent Conducting Oxides (TCOs) are the most common choice as transparent electrodes for optoelectronics applications. In particular, devices, such as LEDs, LCDs, touch screens and solar cells typically employ indium tin oxide. However, indium has some significant drawbacks, including toxicity issues (which are hampering manufacturing), an increasing rarefication (due to a combination of relative scarcity and increasing demand [1]) and resulting price increases. Moreover, there is no satisfactory option at the moment for use as a p-type transparent contact. Thus alternative materials solutions are actively being sought. This review will compare the performance and perspectives of graphene with respect to TCOs for use in transparent conductor applications.

Sandana, V. E.; Rogers, D. J.; Teherani, F. Hosseini; Bove, P.; Razeghi, M.

2013-03-01

18

Transparent electrode for optical switch  

DOEpatents

The invention relates generally to optical switches and techniques for applying a voltage to an electro-optical crystal, and more particularly, to transparent electodes for an optical switch. System architectures for very large inertial confinement fusion (ICF) lasers require active optical elements with apertures on the order of one meter. Large aperture optical switches are needed for isolation of stages, switch-out from regenerative amplifier cavities and protection from target retroreflections.

Goldhar, J.; Henesian, M.A.

1984-10-19

19

Counter electrodes in transmissive electrochromic light modulators  

SciTech Connect

Transmissive electrochromic light modulators require two electrodes to be in the light path, a primary electrochromic material and a charge-balancing counter electrode (CE). Two insertion-type CEs are reviewed, IrO{sub 2}, for operation in protic environments, and V{sub 2}O{sub 5} for operation in non-aqueous, Li-based electrolytes. Both undergo anodic coloration processes which complement the blue cathodic coloration of WO{sub 3}. Reversible and deep visible light transmission modulation has been demonstrated for WO{sub 3}/IrO{sub 2} and WO{sub 3}/V{sub 2}O{sub 5} series combinations.

Rauh, R.D.; Cogan, S.F. (EIC Labs., Inc., Norwood, MA (United States))

1988-01-01

20

Optically transparent porous metal foam electrode  

Microsoft Academic Search

The development of porous metal foam has made possible the construction of a porous metal foam optically transparent electrode (PMF-OTE). PMF is similar to reticulated vitreous carbon in its structure and optical properites. The fabrication and evaluation of PMF for use as an OTE are presented.

David E. Hobart; Vincent E. Norvell; Peter G. Varlashkin; Herbert E. Hellwege; Joseph R. Peterson

1983-01-01

21

Copper Nanowires as Fully Transparent Conductive Electrodes  

PubMed Central

In pondering of new promising transparent conductors to replace the cost rising tin-doped indium oxide (ITO), metal nanowires have been widely concerned. Herein, we demonstrate an approach for successful synthesis of long and fine Cu nanowires (NWs) through a novel catalytic scheme involving nickel ions. Such Cu NWs in high aspect ratio (diameter of 16.2 ± 2?nm and length up to 40??m) provide long distance for electron transport and, meanwhile, large space for light transmission. Transparent electrodes fabricated using the Cu NW ink achieve a low sheet resistance of 1.4?Ohm/sq at 14% transmittance and a high transparency of 93.1% at 51.5?Ohm/sq. The flexibility and stability were tested with 100-timebending by 180°and no resistance change occurred. Ohmic contact was achieved to the p- and n-GaN on blue light emitting diode chip and bright electroluminescence from the front face confirmed the excellent transparency.

Guo, Huizhang; Lin, Na; Chen, Yuanzhi; Wang, Zhenwei; Xie, Qingshui; Zheng, Tongchang; Gao, Na; Li, Shuping; Kang, Junyong; Cai, Duanjun; Peng, Dong-Liang

2013-01-01

22

A new method for obtaining transparent electrodes.  

PubMed

In this article, we propose a simple scheme to make a metallic film on a semi-infinite substrate optically transparent, thus obtaining a completely transparent electrode in a desired frequency range. By placing a composite layer consisting of dielectric and metallic stripes on top of the metallic one, we found that the back-scattering from the metallic film can be almost perfectly canceled by the composite layer under certain conditions, leading to transparency of the whole structure. We performed proof-of-concept experiments in the terahertz domain to verify our theoretical predictions, using carefully designed metamaterials to mimic plasmonic metals in optical regime. Experiments are in excellent agreement with full-wave simulations. PMID:23037428

Malureanu, Radu; Zalkovskij, Maksim; Song, Zhengyong; Gritti, Claudia; Andryieuski, Andrei; He, Qiong; Zhou, Lei; Jepsen, Peter Uhd; Lavrinenko, Andrei V

2012-09-24

23

MWCNT employed counter electrode for DSSCs  

Microsoft Academic Search

In this study, we proposed and investigated the performance of DSSCs with the multi-walled carbon nanotube (MWCNT) on the counter electrode(CE). The 0.45cm2 DSSC device of glass\\/FTO\\/TiO2 blocking layer\\/TiO2(8.5um)\\/Dye(N719)\\/ electrolyte (C6DMII,GSCN)\\/MWCNT\\/FTO\\/glass was fabricated, and then the surface morphology of CEs and the energy conversion efficiency of the DSSC device were characterized by scanning electron microscope(SEM), photocurrent-voltage(I–V), cyclic voltammetry(C-V), and Impedance

Byungkwan Yu; Yunyoung Noh; Jeungjo Han; Ohsung Song

2011-01-01

24

Novel transparent electrodes allow sustainable production of electronic devices  

Microsoft Academic Search

A novel technique for fabricating inexpensive, transparent electrodes from common metals has been developed by engineers and scientists at Iowa State University and Ames Laboratory. They exhibit very high transparency and are very good electrical conductors. This is a combination of properties that is difficult to achieve with common materials. The most frequently used transparent electrode in today's high-technology devices

Constant; Kristen

2010-01-01

25

Fabrication and Chemical Doping of Carbon-based Transparent Electrodes  

Microsoft Academic Search

The use of carbon-based materials (carbon nanotubes and graphene) as transparent electrodes has attracted enormous interest due to their high conductivities, transparency and potential as a lower cost alternative to traditional transparent electrode materials (i.e. Indium Tin Oxide). This talk will focus on using solution processes to suspend both carbon nanotubes and graphene flakes in solution and the fabrication of

George Tulevski; Ali Afzali

2009-01-01

26

High-Efficiency Graphene Photo Sensor Using a Transparent Electrode  

Microsoft Academic Search

We report the first implementation of transparent electrodes in bottom-gate graphene transistors used for photo detection. Compared to conventional nontransparent electrodes, the transparent electrodes allow photons to transmit through to the graphene beneath, providing an enlarged absorption area and thereby giving rise to an enhancement of photocurrent generation. The devices are fabricated with an asymmetric metallization scheme and the experimental

Tao Liu; Zheng Huang

2011-01-01

27

Effect of Counter Electrode in Electroformation of Giant Vesicles  

PubMed Central

Electroformation of cell-sized lipid membrane vesicles (giant vesicles, GVs), from egg yolk phosphatidylcholine, was examined varying the shape of the counter electrode. Instead of a planar ITO (indium tin oxide) electrode commonly used, platinum wire mesh was employed as a counter electrode facing lipid deposit on a planar formation electrode. The modification did not significantly alter GV formation, and many GVs of 30–50 ?m, some as large as 100 ?m, formed as with the standard setup, indicating that a counter electrode does not have to be a complete plane. When the counter electrode was reduced to a set of two parallel platinum wires, GV formation deteriorated. Some GVs formed, but only in close proximity to the counter electrode. Lower electric voltage with this setup no longer yielded GVs. Instead, a large onion-like multilamellar structure was observed. The deteriorated GV formation and the formation of a multilamellar structure seemed to indicate the weakened effect of the electric field on lipid deposit due to insufficient coverage with a small counter electrode. Irregular membranous objects formed by spontaneous swelling of lipid without electric voltage gradually turned into multilamellar structure upon following application of voltage. No particular enhancement of GV formation was observed when lipid deposit on a wire formation electrode was used in combination with a large planar counter electrode.

Okumura, Yukihisa; Oana, Shuuhei

2011-01-01

28

Transparent metal electrodes from ordered nanosphere arrays  

NASA Astrophysics Data System (ADS)

We show that perforated metal electrode arrays, fabricated using nanosphere lithography, provide a viable alternative to conductive metal oxides as transparent electrode materials. The inter-aperture spacing is tuned by varying etching times in an oxygen plasma, and the effect of inter-aperture ``wire'' thickness on the optical and electronic properties of perforated silver films is shown. Optical transmission is limited by reflection and surface plasmons, and for these results do not exceed 73%. Electrical sheet resistance is shown to be as low as 3 ? ?-1 for thermally evaporated silver films. The performance of organic photovoltaic devices comprised of a P3HT:PCBM bulk heterojunction deposited onto perforated metal arrays is shown to be limited by optical transmission, and a simple model is presented to overcome these limitations.

Morfa, Anthony J.; Akinoglu, Eser M.; Subbiah, Jegadesan; Giersig, Michael; Mulvaney, Paul

2013-08-01

29

Flexible, transparent electrodes using carbon nanotubes  

PubMed Central

We prepare thin single-walled carbon nanotube networks on a transparent and flexible substrate with different densities, using a very simple spray method. We measure the electric impedance at different frequencies Z(f) in the frequency range of 40?Hz to 20?GHz using two different methods: a two-probe method in the range up to 110?MHz and a coaxial (Corbino) method in the range of 10?MHz to 20?GHz. We measure the optical absorption and electrical conductivity in order to optimize the conditions for obtaining optimum performance films with both high electrical conductivity and transparency. We observe a square resistance of 1 to 8.5?k? for samples showing 65% to 85% optical transmittance, respectively. For some applications, we need flexibility and not transparency: for this purpose, we deposit a thick film of single-walled carbon nanotubes on a flexible silicone substrate by spray method from an aqueous suspension of carbon nanotubes in a surfactant (sodium dodecyl sulphate), thereby obtaining a flexible conducting electrode showing an electrical resistance as low as 200??/sq. When stretching up to 10% and 20%, the electrical resistance increases slightly, recovering the initial value for small elongations up to 10%. We analyze the stretched and unstretched samples by Raman spectroscopy and observe that the breathing mode on the Raman spectra is highly sensitive to stretching. The high-energy Raman modes do not change, which indicates that no defects are introduced when stretching. Using this method, flexible conducting films that may be transparent are obtained just by employing a very simple spray method and can be deposited on any type or shape of surface.

2012-01-01

30

Graphene Transparent Conductive Electrodes for Next- Generation Microshutter Arrays  

NASA Technical Reports Server (NTRS)

Graphene is a single atomic layer of graphite. It is optically transparent and has high electron mobility, and thus has great potential to make transparent conductive electrodes. This invention contributes towards the development of graphene transparent conductive electrodes for next-generation microshutter arrays. The original design for the electrodes of the next generation of microshutters uses indium-tin-oxide (ITO) as the electrode material. ITO is widely used in NASA flight missions. The optical transparency of ITO is limited, and the material is brittle. Also, ITO has been getting more expensive in recent years. The objective of the invention is to develop a graphene transparent conductive electrode that will replace ITO. An exfoliation procedure was developed to make graphene out of graphite crystals. In addition, large areas of single-layer graphene were produced using low-pressure chemical vapor deposition (LPCVD) with high optical transparency. A special graphene transport procedure was developed for transferring graphene from copper substrates to arbitrary substrates. The concept is to grow large-size graphene sheets using the LPCVD system through chemical reaction, transfer the graphene film to a substrate, dope graphene to reduce the sheet resistance, and pattern the film to the dimension of the electrodes in the microshutter array. Graphene transparent conductive electrodes are expected to have a transparency of 97.7%. This covers the electromagnetic spectrum from UV to IR. In comparison, ITO electrodes currently used in microshutter arrays have 85% transparency in mid-IR, and suffer from dramatic transparency drop at a wavelength of near-IR or shorter. Thus, graphene also has potential application as transparent conductive electrodes for Schottky photodiodes in the UV region.

Li, Mary; Sultana, Mahmooda; Hess, Larry

2012-01-01

31

Solution-processed metal nanowire mesh transparent electrodes.  

PubMed

Transparent conductive electrodes are important components of thin-film solar cells, light-emitting diodes, and many display technologies. Doped metal oxides are commonly used, but their optical transparency is limited for films with a low sheet resistance. Furthermore, they are prone to cracking when deposited on flexible substrates, are costly, and require a high-temperature step for the best performance. We demonstrate solution-processed transparent electrodes consisting of random meshes of metal nanowires that exhibit an optical transparency equivalent to or better than that of metal-oxide thin films for the same sheet resistance. Organic solar cells deposited on these electrodes show a performance equivalent to that of devices based on a conventional metal-oxide transparent electrode. PMID:18189445

Lee, Jung-Yong; Connor, Stephen T; Cui, Yi; Peumans, Peter

2008-02-01

32

A membrane mirror with transparent electrode for adaptive optics  

NASA Astrophysics Data System (ADS)

Membrane deformable mirror devices consist of a single large membrane that is suspended above an array of actuating electrodes. A transparent electrode is incorporated into the membrane mirror device in the optical path in an effort to provide significantly greater control of the membrane, and hence improved performance in an adaptive optics system. The devices presented here were fabricated from 1 mm thickness SOI; devices were bonded to electrode arrays with 1024 electrodes, packaged in ceramic pin grid arrays and driven by off chip D/A electronics. The transparent electrodes consist of glass that is ITO coated for electrical conductivity and visible light transmission. An electrode is inserted into a recessed cavity of each membrane chip, and is positioned 70 mm above the membrane. With 2x2 binned electrodes, the device demonstrates 10 mm deflection toward the electrode array at 40 V. Large deflection at low voltage is obtained because of the low intrinsic stress of the silicon membrane. These data also demonstrate modest deflection toward the transparent electrode, which may be improved with better alignment of the transparent electrode with the underlying membrane and electrode array in future devices.

Kurczynski, Peter L.; Dyson, Harold M.; Sadoulet, Bernard; Bower, J. Eric; Lai, Warren Y.; Mansfield, William M.; Taylor, J. Ashley

2005-01-01

33

An Electrochemical Experiment Using an Optically Transparent Thin Layer Electrode  

ERIC Educational Resources Information Center

Describes a unified experiment in which an optically transparent thin layer electrode is used to illustrate the techniques of thin layer electrochemistry, cyclic voltammetry, controlled potential coulometry, and spectroelectrochemistry. (MLH)

DeAngelis, Thomas P.; Heineman, William R.

1976-01-01

34

Failure of silver nanowire transparent electrodes under current flow  

PubMed Central

Silver nanowire transparent electrodes have received much attention as a replacement for indium tin oxide, particularly in organic solar cells. In this paper, we show that when silver nanowire electrodes conduct current at levels encountered in organic solar cells, the electrodes can fail in as little as 2?days. Electrode failure is caused by Joule heating which causes the nanowires to breakup and thus create an electrical discontinuity in the nanowire film. More heat is created, and thus failure occurs sooner, in more resistive electrodes and at higher current densities. Suggestions to improve the stability of silver nanowire electrodes are given.

2013-01-01

35

Counter-electrode function in nanocrystalline photoelectrochemical cell configurations  

Microsoft Academic Search

The search for rigid or flexible photoelectrochemical solar cell counter-electrode (CE) alternatives has been a continuous effort and long ongoing process in our lab, as studies in CE kinetic performance and stability on the one hand seek to improve the overall efficiency of the solar cell, while attempting to adapt to novel design concepts or new materials, on the other.

N. Papageorgiou

2004-01-01

36

Single-Wall Carbon Nanotubes as Transparent Electrodes for Photovoltaics  

SciTech Connect

Transparent and electrically conductive coatings and films have a variety of uses in the fast-growing field of optoelectronic applications. Transparent electrodes typically include semiconductive metal oxides such as indium tin oxide (ITO), and conducting polymers such as poly(3,4-ethylenedioxythiophene), doped and stabilized with poly(styrenesulfonate) (PEDOT/PSS). In recent years, Eikos, Inc. has conceived and developed technologies to deliver novel alternatives using single-wall carbon nanotubes (SWNT). These technologies offer products having a broad range of conductivity, excellent transparency, neutral color tone, good adhesion, abrasion resistance as well as mechanical robustness. Additional benefits include ease of ambient processing and patterning capability. This paper reports our recent findings on achieving 2.6% and 1.4% efficiencies on nonoptimized organic photovoltaic cells employing SWNT as a transparent electrode.

Weeks, C.; Peltola, J.; Levitsky, I.; Glatkowski, P.; van de Lagemaat, J.; Rumbles, G.; Barnes, T.; Coutts, T.

2006-01-01

37

Surface-Plasmon Enhanced Transparent Electrodes in Organic Photovoltaics  

SciTech Connect

Random silver nanohole films were created through colloidal lithography techniques and metal vapor deposition. The transparent electrodes were characterized by uv-visible spectroscopy and incorporated into an organic solar cell. The test cells were evaluated for solar power-conversion efficiency and incident photon-to-current conversion efficiency. The incident photon-to-current conversion efficiency spectra displayed evidence that a nanohole film with 92 nm diameter holes induces surface-plasmon-enhanced photoconversion. The nanohole silver films demonstrate a promising route to removing the indium tin oxide transparent electrode that is ubiquitous in organic optoelectronics.

Reilly III, T. H.; van de Lagemaat, J.; Tenent, R. C.; Morfa, A. J.; Rowlen, K. L.

2008-01-01

38

Optimization of transparent electrode for solar cells  

NASA Astrophysics Data System (ADS)

A simple, sensitive, and reliable method for measuring the interfacial or contact resistance between tin oxide and silicon is reported. The method consists of depositing a doped tin oxide layer on a wafer of highly conductive single-crystal silicon. Metallic electrodes are applied to the surface of the tin oxide and to the opposite surface of the silicon. The coated and soldered wafer is then clamped between flat metallic electrodes, and the resistance between the electrodes is measured with an ohm meter. Corrections are estimated for the resistance of the wafer, the bulk of the tin oxide, and for the resistance at the indium-silicon and indium-tin oxide interfaces. The method is called the two-point interfacial resistance method. A four-point probe method was investigated which was less satisfactory than the two-point method. Both methods were applied to tin oxide coatings deposited on single crystal silicon wafers at 500 C.

Gordon, R. G.

39

Optimization of transparent electrode for solar cells  

Microsoft Academic Search

A simple, sensitive, and reliable method for measuring the interfacial or contact resistance between tin oxide and silicon is reported. The method consists of depositing a doped tin oxide layer on a wafer of highly conductive single-crystal silicon. Metallic electrodes are applied to the surface of the tin oxide and to the opposite surface of the silicon. The coated and

R. G. Gordon

1982-01-01

40

Graphene as a transparent conducting electrode for photovoltaics  

Microsoft Academic Search

Current photovoltaic techonologies rely on expensive oxide films as transparent conducting electrodes (TCEs). With less than two percent absorption per layer and a high carrier mobility, graphene stands as a prominent candidate for TCEs. In this work, we investigate the structural and electronic properties of several doped graphene layers using density functional theory. Of particular interest is the interface between

Razvan Nistor; Marcelo Kuroda; Ahmed Maarouf; Dennis Newns; Glenn Martyna

2010-01-01

41

Organic solar cells with solution-processed graphene transparent electrodes  

Microsoft Academic Search

We demonstrate that solution-processed graphene thin films can serve as transparent conductive anodes for organic photovoltaic cells. The graphene electrodes were deposited on quartz substrates by spin coating of an aqueous dispersion of functionalized graphene, followed by a reduction process to reduce the sheet resistance. Small molecular weight organic solar cells can be directly deposited on such graphene anodes. The

Junbo Wu; Héctor A. Becerril; Zhenan Bao; Zunfeng Liu; Yongsheng Chen; Peter Peumans

2008-01-01

42

Transparent conductive electrodes for electrochromic devices: A review  

Microsoft Academic Search

This paper reviews the optical and electrical performance of thin films that are useful as transparent electrodes in electrochromic devices. The properties of certain heavily doped wide-bandgap semiconductor oxides (especially In2O3:Sn) and of certain coinage metal films are discussed.

C. G. Granqvist

1993-01-01

43

Hot-rolling nanowire transparent electrodes for surface roughness minimization  

PubMed Central

Silver nanowire transparent electrodes are a promising alternative to transparent conductive oxides. However, their surface roughness presents a problem for their integration into devices with thin layers such as organic electronic devices. In this paper, hot rollers are used to soften plastic substrates with heat and mechanically press the nanowires into the substrate surface. By doing so, the root-mean-square surface roughness is reduced to 7 nm and the maximum peak-to-valley value is 30 nm, making the electrodes suitable for typical organic devices. This simple process requires no additional materials, which results in a higher transparency, and is compatible with roll-to-roll fabrication processes. In addition, the adhesion of the nanowires to the substrate significantly increases.

2014-01-01

44

Carbon Nanotube Assemblies for Transparent Conducting Electrodes  

SciTech Connect

The goal of this chapter is to introduce readers to the fundamental and practical aspects of nanotube assemblies made into transparent conducting networks and discuss some practical aspects of their characterization. Transparent conducting coatings (TCC) are an essential part of electro-optical devices, from photovoltaics and light emitting devices to electromagnetic shielding and electrochromic widows. The market for organic materials (including nanomaterials and polymers) based TCCs is expected to show a growth rate of 56.9% to reach nearly 20.3billionin2015,whilethemarketfortraditionalinorganictransparentelectronicswillexperiencegrowthwithratesof6.7103 billion in 2015. Emerging flexible electronic applications have brought additional requirements of flexibility and low cost for TCC. However, the price of indium (the major component in indium tin oxide TCC) continues to increase. On the other hand, the price of nanomaterials has continued to decrease due to development of high volume, quality production processes. Additional benefits come from the low cost, nonvacuum deposition of nanomaterials based TCC, compared to traditional coatings requiring energy intensive vacuum deposition. Among the materials actively researched as alternative TCC are nanoparticles, nanowires, and nanotubes with high aspect ratio as well as their composites. The figure of merit (FOM) can be used to compare TCCs made from dissimilar materials and with different transmittance and conductivity values. In the first part of this manuscript, we will discuss the seven FOM parameters that have been proposed, including one specifically intended for flexible applications. The approach for how to measure TCE electrical properties, including frequency dependence, will also be discussed. We will relate the macroscale electrical characteristics of TCCs to the nanoscale parameters of conducting networks. The fundamental aspects of nanomaterial assemblies in conducting networks will also be addressed. We will review recent literature on TCCs composed of carbon nanotubes of different types in terms of the FOM.

Garrett, Matthew P [ORNL] [ORNL; Gerhardt, Rosario [ORNL] [ORNL

2012-01-01

45

Novel transparent electrodes allow sustainable production of electronic devices  

SciTech Connect

A novel technique for fabricating inexpensive, transparent electrodes from common metals has been developed by engineers and scientists at Iowa State University and Ames Laboratory. They exhibit very high transparency and are very good electrical conductors. This is a combination of properties that is difficult to achieve with common materials. The most frequently used transparent electrode in today's high-technology devices (such as LCD screens) is indium tin oxide (ITO). While ITO performs well in these applications, the supply of indium is very limited. In addition, it is rapidly decreasing as consumer demand for flat-panel electronics is skyrocketing. According to a 2004 US Geological Survey report, as little as 14 years exploitation of known indium reserves remains. In addition to increasing prices, the dwindling supply of indium suggests its use is not sustainable for future generations of electronics enthusiasts. Solar cells represent another application where transparent electrodes are used. To make solar-energy collection economically feasible, all parts of solar photovoltaics must be made more efficient and cost-effective. Our novel transparent electrodes have the potential to do both. In addition, there is much interest in developing more efficient, cost-effective, and environmentally friendly lighting. Incandescent light bulbs are very inefficient, because most of their energy consumption is wasted as heat. Fluorescent lighting is much more efficient but still uses mercury, an environmental toxin. An attractive alternative is offered by LEDs, which have very high efficiencies and long lifetimes, and do not contain mercury. If made bright enough, LED use for general lighting could provide a viable alternative. We have fabricated electrodes from more commonly available materials, using a technique that is cost effective and environmentally friendly. Most of today's electronic devices are made in specialized facilities equipped with low-particle-count clean-room facilities and multimillion-dollar equipment. On the other hand, the novel process we developed uses a method that makes use of polymer molds and standard deposition techniques in an ambient laboratory environment. The final structure consists of tall ribbons of metal (standing on edge) that are so thin that they do not block light but are very good conductors. The advantage of this design is that it avoids the competition between conductivity and transparency inherent in transparent oxide electrodes. By making the structure taller, conductivity can be increased without impacting transparency. We have measured both electrical conductivity and transparency for these structures. We performed two-wire electrical measurements to quantify the structures resistance using metal contacts deposited on each end. The total sample area was 4 x 4mm{sup 2}. We measured a resistance of structures with 40nm gold sidewalls of 7.3{Omega}, which is lower than that of ITO glass (which has a sheet resistance around 10O/square). We investigated the structures optical properties based on both specular- and total-transmission measurements. Specular transmission is measured by collecting the transmitted light at normal incidence, while total transmission is obtained by collecting transmitted light at normal incidence and diffracted light using an integrating sphere. Figure 3 shows the total transmission of a grating with 40nm gold or silver sidewalls on a glass substrate compared to that of ITO. Additionally, the transparency changes very little within 30{sup o} off normal incidence. This high visible-light transmission of our metal-patterned structures is very promising for their application as transparent electrodes, because most visible light was allowed to propagate through the patterned metallic/polymeric structures. Researchers in our group continue to refine the fabrication methods and are investigating methods to make large-scale structures for use in a variety of applications that require both transparency and high electrical conductivity. We are also applying these fab

Constant, Kristen

2010-12-27

46

Transparent, conductive graphene electrodes for dye-sensitized solar cells.  

PubMed

Transparent, conductive, and ultrathin graphene films, as an alternative to the ubiquitously employed metal oxides window electrodes for solid-state dye-sensitized solar cells, are demonstrated. These graphene films are fabricated from exfoliated graphite oxide, followed by thermal reduction. The obtained films exhibit a high conductivity of 550 S/cm and a transparency of more than 70% over 1000-3000 nm. Furthermore, they show high chemical and thermal stabilities as well as an ultrasmooth surface with tunable wettability. PMID:18069877

Wang, Xuan; Zhi, Linjie; Müllen, Klaus

2008-01-01

47

Two-dimensional metamaterial transparent metal electrodes for infrared optoelectronics.  

PubMed

We examine the optical properties of two-dimensionally nanostructured metals in the metamaterial regime for infrared applications. Compared with straight nanowires and nanogrids, serpentine structures exhibit much lower optical losses of less than 7% even at a large metal area fraction of 0.3. The low loss is primarily due to a small effective conductivity of the meandering structures, and self-inductance plays a modest role in reducing losses in these structures. The high transparency at a large metal area coverage would be useful for transparent electrodes in optoelectronic devices. PMID:24978563

Clark, Samuel M; Han, Sang Eon

2014-06-15

48

Electro-deposited vanadium oxide as a counter-electrode for PProDOT-Me2 based electrochromic devices (ECDs)  

NASA Astrophysics Data System (ADS)

A preparation and characterization of thin film vanadium oxide for use as a transparent ion storage layer/counter-electrode in organic ECDs is reported. A cathodic polymer film, Poly[3,3-dimethyle-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine] (PProDOT-Me2) was used as the electrochromic material. Counter-electrodes were prepared using a sol-gel method and deposited using electrophoresis. Indium Tin oxide (I TO) glass was used as an electrically conductive and transparent substrate. This paper focuses on optimized characteristics complimentary to a PProDOT-Me2 based electrochromic thin film. Gels of vanadium oxide were created from V2O5 powder mixed with hydrogen peroxide (H2O2) and deionized water. Thin films were deposited onto a substrate submerged in the solution and subjected to cyclic voltammetry. Deposition parameters were varied and their effect on counter electrode characteristics investigated. The thin film exhibited a capacitance curve similar to the PProDOT-Me2 based EC film while maintaining a transmittance greater than 60% indicating that V2O5 is a suitable material. The ensuing 1 inch x 1 inch smart window exhibits a change in transmittance of 60% and a lifetime of over 100,000 cycles at a switching speed of 1 second. Larger sized devices of six and twelve inches were successfully prepared and switched between the dark blue and transparent states in less than 15 seconds.

Kaneko, Calen; Xu, Chunye; Liu, Lu; Ning, Dai; Taya, Minoru

2005-05-01

49

Fissile material transparency technology demonstration : neutron multiplicity counter /  

SciTech Connect

The Fissile Material Transparency Technology Demonstration occurred at Los Alamos National Laboratory, August 14-17, 2000. The demonstration showed the determination of six attributes (Pu presence, Pu isotopics, Pu mass, absence of oxide, symmetry, and age) on unclassified plutonium samples and a US nuclear weapons component. The demonstrations showed that a six-attribute measurement system with information barrier could be fabricated and was capable of protecting classified information. In order to measure the six attributes, a high-resolution gamma-ray spectroscopy system and neutron multiplicity system were developed. This talk discusses the neutron multiplicity system, along with data taken on the unclassified samples.

Bourret, S. C.; Harker, W. C. (William C.); Hypes, P. A. (Philip A.); Langner, D. C. (Diana C.); Salazar, S. D. (Steven D.); Siebelist, R. (Richard); Smith, M. K. (Morag K.); Sweet, M. R. (Martin R.); Mayo, D. R. (Douglas R.)

2001-01-01

50

Comparison of transparent conducting electrodes on mercuric iodide photocells  

NASA Astrophysics Data System (ADS)

Three materials have been developed and tested which are suitable as transparent conducting electrodes on mercuric iodide; aqueous ionic contacts of NaCl and LiCl, polyvinyl alcohol/phosphoric acid, and indium--tin--oxide (ITO). Polyvinyl alcohol/phosphoric acid is a conducting polymer and ITO is a wide band gap semiconductor. Photocell dimensions were in the range of 0.5 to 3.8 cm diam by about 1 mm thick. Photocells with these electrodes were evaluated for their spectral response in the range of 300 to 650 nm, response uniformity over the electrode activities area, leakage current and reliability. All units showed better than 75 percent quantum efficiency in the range 350 to 550 nm. Photodetector leakage currents ranged from 25 to 200 pA and have shown long term stability up to 1 year.

Cheng, A. Y.; Markakis, J. M.

51

Anthocyanin-sensitized solar cells using carbon nanotube films as counter electrodes  

NASA Astrophysics Data System (ADS)

Carbon nanotube (CNT) films have been used as counter electrodes in natural dye-sensitized (anthocyanin-sensitized) solar cells to improve the cell performance. Compared with conventional cells using natural dye electrolytes and platinum as the counter electrodes, cells with a single-walled nanotube (SWNT) film counter electrode show comparable conversion efficiency, which is attributed to the increase in short circuit current density due to the high conductivity of the SWNT film.

Zhu, Hongwei; Zeng, Haifeng; Subramanian, Venkatachalam; Masarapu, Charan; Hung, Kai-Hsuan; Wei, Bingqing

2008-11-01

52

Developing Infrared (IR) Transparent Conductive Electrode Technology for Multi-Functional Infrared (IR) Sensing.  

National Technical Information Service (NTIS)

Transparent conductive electrode technology has long been desired in a great variety of applications, such as light-emitting diode (LED), solar cells, transparent smart skins, invisible electronics and antennas, and embedded sensing and imaging. Current s...

X. Lu

2011-01-01

53

Transparency controllable silver-based electrode for flexible optoelectronics  

NASA Astrophysics Data System (ADS)

The transmittance of Ag-based electrode increased through suppressing surface plasmons (SPs) coupling. When 10-nm-thick Ag was deposited on small-dielectric-constant (?) film (LiF, SiO), SPs coupling was induced, resulting in low transmittance (<40%) in visible region. At the Ag/large-? oxide interface (WO3 and MoO3), SPs were suppressed, and the film showed increased transmittance (~80%). Organic light emitting diodes using Ag/WO3 (?: 35) as a transparent electrode showed 1.26 times greater luminance and 32.6% greater power efficiency than using Ag/LiF (?: 5). These results provide us with an important guideline for enhancing the transmittance of Ag/dielectric film by controlling SPs coupling.

Kim, Kisoo; Hong, Kihyon; Koo, Bonhyeong; Lee, Illhwan; Lee, Jong-Lam

2013-02-01

54

Silicon metal-semiconductor–metal photodetector with zinc oxide transparent conducting electrodes  

Microsoft Academic Search

Transparent conducting oxides thin layers, due to their optical and electrical properties, can be used as transparent electrodes in various optoelectronic devices. We present a metal-semiconductor–metal photodiode (MSM-PD) on silicon as optically active layer with zinc oxide (ZnO) thin layer as interdigitated Schottky transparent electrodes. The advantage of using a ZnO thin layer as Schottky electrodes consists in the improvement

E. Budianu; M. Purica; F. Iacomi; C. Baban; P. Prepelita; E. Manea

2008-01-01

55

Double-layer CVD graphene as stretchable transparent electrodes.  

PubMed

The stretchability of CVD graphene with a large area is much lower than that of mechanically exfoliated pristine graphene owing to the intrinsic and extrinsic defects induced during its synthesis, etch-out of the catalytic metal, and the transfer processes. This low stretchability is the main obstacle for commercial application of CVD graphene in the field of flexible and stretchable electronics. In this study, artificially layered CVD graphene is suggested as a promising candidate for a stretchable transparent electrode. In contrast to single-layer graphene (SLG), multi-layer graphene has excellent electromechanical stretchability owing to the strain relaxation facilitated by sliding among the graphene layers. Macroscopic and microscopic electromechanical tensile tests were performed to understand the key mechanism for the improved stretchability, and crack generation and evolution were systematically investigated for their dependence on the number of CVD graphene layers during tensile deformation using lateral force microscopy. The stretchability of double-layer graphene (DLG) is much larger than that of SLG and is similar to that of triple-layer graphene (TLG). Considering the transmittance and the cost of transfer, DLG can be regarded as a suitable candidate for stretchable transparent electrodes. PMID:24781278

Won, Sejeong; Hwangbo, Yun; Lee, Seoung-Ki; Kim, Kyung-Shik; Kim, Kwang-Seop; Lee, Seung-Mo; Lee, Hak-Joo; Ahn, Jong-Hyun; Kim, Jae-Hyun; Lee, Soon-Bok

2014-06-01

56

Facile construction of high-electrocatalytic bilayer counter electrode for efficient dye-sensitized solar cells.  

PubMed

To improve the mechanical rigidity of the electrocatalyst and assure a higher number density of catalytic sites of the counter electrode in dye-sensitized solar cells (DSCs), we have extended widely applied titanium tetrachloride treatment to construct a rough scaffolding underlayer for the platinized counter electrode. Field-emission scanning electron microscopy and atomic force microscopy images clearly depicted the platinum nanoparticles with a diameter of ca. 10 nm homogeneously distributed on the scaffolding underlayer of the bilayer counter electrode and thus led to a characteristically high surface roughness. The electocatalytic activity of this novel bilayer counter electrode was measured and compared with the corresponding properties of conventional sputtered Pt electrode. Interestingly, electrochemical impedance spectroscopy and cyclic voltammetry measurements further demonstrated the notably larger electrochemical active surface area and thereby higher electrocatalytic activity of the bilayer counter electrode. Consequently, under standard 1 sun illumination (100 mW cm(-2), AM 1.5), device with this bilayer counter electrode achieved a considerably improved fill factor of 0.67 and overall energy conversion efficiency of 7.09%, which was apparently higher than that of 0.60 and 6.37% for sputterd Pt electrode. Therefore, this present method paves a facile and inexpensive way to prepare high-electrocatalytic bilayer counter electrode in DSCs. PMID:21888398

Hao, Feng; Lin, Hong; Liu, Yizhu; Wang, Ning; Li, Wendi; Li, Jianbao

2011-10-01

57

Spectroscopic and electrochemical characterization of nanostructured optically transparent carbon electrodes.  

PubMed

The present paper describes the results related to the optical and electrochemical characterization of thin carbon films fabricated by spin coating and pyrolysis of AZ P4330-RS photoresist. The goal of this paper is to provide comprehensive information allowing for the rational selection of the conditions to fabricate optically transparent carbon electrodes (OTCE) with specific electrooptical properties. According to our results, these electrodes could be appropriate choices as electrochemical transducers to monitor electrophoretic separations. At the core of this manuscript is the development and critical evaluation of a new optical model to calculate the thickness of the OTCE by variable angle spectroscopic ellipsometry. Such data were complemented with topography and roughness (obtained by atomic force microscopy), electrochemical properties (obtained by cyclic voltammetry), electrical properties (obtained by electrochemical impedance spectroscopy), and structural composition (obtained by Raman spectroscopy). Although the described OTCE were used as substrates to investigate the effect of electrode potential on the real-time adsorption of proteins by ellipsometry, these results could enable the development of other biosensors that can be then integrated into various CE platforms. PMID:23595607

Benavidez, Tomás E; Garcia, Carlos D

2013-07-01

58

Design of dielectric/metal/dielectric transparent electrodes for flexible electronics  

NASA Astrophysics Data System (ADS)

A flexible transparent electrode (FTE) is one of the most essential parts for the next generation of flexible optoelectronic devices, including solar cells, displays, and solid-state lighting devices. Although a lot of candidate materials for the FTE such as metallic nanowires, carbon nanotube, and graphene have been investigated, each material has fundamental limits as FTE applications, such as low transmittance (70% to 80%), high sheet resistance (>100 ohm/sq) and rough surface morphology. Dielectric/metal/dielectric (DMD) electrode structure is a promising candidate for next-generation flexible transparent electrodes. Compared with other transparent electrodes, DMD electrodes show best performance in terms of optical transparency, sheet resistance, and mechanical flexibility. In addition, it has been also reported that the device performances can be significantly enhanced by the microcavity effects with the DMD electrodes. We review the relevant principles and discusses recent progress in DMD electrodes.

Kim, Sungjun; Lee, Jong-Lam

2012-01-01

59

Polycarbazole nanocomposites with conducting metal oxides for transparent electrode applications.  

PubMed

The preparation and characterization of conducting polycarbazole (PCz) hybrid films with a colorless transparency are described. They were prepared by the vacuum evaporation of tin, aluminum, or gallium onto anion-doped green-colored PCz films, or by applying gallium to the films, followed by their exposure to ambient air. The resultant hybrid films consisting of an undoped PCz backbone and metal compounds exhibited good transparencies (90-95% at a wavelength of 550 nm). The hybrid films have a specific cross-sectional structure in which the small regions of the metal compounds are dispersed in the PCz backbone. The hybridization reaction was mechanistically explained on the basis of the combination of a metal corrosion reaction and polymer dedoping reaction, which was successfully supported by the chemical analyses of the hybrid films. The electric conductivities of the hybrid films, measured by a four-point-probe method, ranged from 2.2 x 10(-4) to 6.0 x 10(-3) S cm(-1), which are considered to be the lowest limit because the use of the hybrid films as an electrochemical electrode reveals that a network of conductive paths is preferentially formed in the film thickness direction rather than in the in-plane direction. PMID:20356187

Hoshino, Katsuyoshi; Yazawa, Naoki; Tanaka, Yoshiyasu; Chiba, Takeshi; Izumizawa, Takenori; Kubo, Minako

2010-02-01

60

Ultrasmooth, extremely deformable and shape recoverable Ag nanowire embedded transparent electrode  

NASA Astrophysics Data System (ADS)

Transparent electrodes have been widely used in electronic devices such as solar cells, displays, and touch screens. Highly flexible transparent electrodes are especially desired for the development of next generation flexible electronic devices. Although indium tin oxide (ITO) is the most commonly used material for the fabrication of transparent electrodes, its brittleness and growing cost limit its utility for flexible electronic devices. Therefore, the need for new transparent conductive materials with superior mechanical properties is clear and urgent. Ag nanowire (AgNW) has been attracting increasing attention because of its effective combination of electrical and optical properties. However, it still suffers from several drawbacks, including large surface roughness, instability against oxidation and moisture, and poor adhesion to substrates. These issues need to be addressed before wide spread use of metallic NW as transparent electrodes can be realized. In this study, we demonstrated the fabrication of a flexible transparent electrode with superior mechanical, electrical and optical properties by embedding a AgNW film into a transparent polymer matrix. This technique can produce electrodes with an ultrasmooth and extremely deformable transparent electrode that have sheet resistance and transmittance comparable to those of an ITO electrode.

Nam, Sanggil; Song, Myungkwan; Kim, Dong-Ho; Cho, Byungjin; Lee, Hye Moon; Kwon, Jung-Dae; Park, Sung-Gyu; Nam, Kee-Seok; Jeong, Yongsoo; Kwon, Se-Hun; Park, Yun Chang; Jin, Sung-Ho; Kang, Jae-Wook; Jo, Sungjin; Kim, Chang Su

2014-04-01

61

Ultrasmooth, extremely deformable and shape recoverable Ag nanowire embedded transparent electrode  

PubMed Central

Transparent electrodes have been widely used in electronic devices such as solar cells, displays, and touch screens. Highly flexible transparent electrodes are especially desired for the development of next generation flexible electronic devices. Although indium tin oxide (ITO) is the most commonly used material for the fabrication of transparent electrodes, its brittleness and growing cost limit its utility for flexible electronic devices. Therefore, the need for new transparent conductive materials with superior mechanical properties is clear and urgent. Ag nanowire (AgNW) has been attracting increasing attention because of its effective combination of electrical and optical properties. However, it still suffers from several drawbacks, including large surface roughness, instability against oxidation and moisture, and poor adhesion to substrates. These issues need to be addressed before wide spread use of metallic NW as transparent electrodes can be realized. In this study, we demonstrated the fabrication of a flexible transparent electrode with superior mechanical, electrical and optical properties by embedding a AgNW film into a transparent polymer matrix. This technique can produce electrodes with an ultrasmooth and extremely deformable transparent electrode that have sheet resistance and transmittance comparable to those of an ITO electrode.

Nam, Sanggil; Song, Myungkwan; Kim, Dong-Ho; Cho, Byungjin; Lee, Hye Moon; Kwon, Jung-Dae; Park, Sung-Gyu; Nam, Kee-Seok; Jeong, Yongsoo; Kwon, Se-Hun; Park, Yun Chang; Jin, Sung-Ho; Kang, Jae-Wook; Jo, Sungjin; Kim, Chang Su

2014-01-01

62

Hybrid transparent electrodes of silver nanowires and carbon nanotubes: a low-temperature solution process  

NASA Astrophysics Data System (ADS)

Hybrid transparent electrodes with silver nanowires (AgNWs) and single-walled carbon nanotubes (SWCNTs) were fabricated on plastic films by a low-temperature solution process. The hybrid transparent electrodes exhibited a sheet resistance of 29.2 ?/sq with a transparency of 80% when 6 wt.% of SWCNTs was mixed with AgNWs. This sheet resistance was less than one-fourth that of the AgNW transparent electrodes that were prepared using the same method. This reduction in sheet resistance is because the SWCNTs formed bridges between the AgNWs, thus, resulting in high conductivity of the hybrid transparent electrodes. The hybrid electrodes formed on plastic films exhibited high conductivity as well as excellent stability in sheet resistance when tested using a repeated bending test. PACS: 62.23.Hj; 61.48.De; 81.15.-z.

Tokuno, Takehiro; Nogi, Masaya; Jiu, Jinting; Suganuma, Katsuaki

2012-05-01

63

About the transparent electrode of the organic photovoltaic cells  

NASA Astrophysics Data System (ADS)

Electrodes and the nature of their contact with organic materials play a crucial role in the realization of efficient optoelectronic components. Whether the injection (organic light-emitting diodes - OLEDs) or collection (organic photovoltaic cells - OPV cells) of carriers, contacts must be as efficient as possible. To do this, it is customary to refer to electrode surface treatment and/or using a buffer layer all things to optimize the contact. Efficiency of organic photovoltaic cells based on organic electron donor/organic electron acceptor junctions can be strongly improved when the transparent conductive anode is coated with a buffer layer (ABL). We show that an ultra-thin gold (0.5 nm) or a thin molybdenum oxide (3-5 nm) can be used as efficient ABL. However, the effects of these ABL depend on the highest occupied molecular orbital (HOMO) of different electron donors of the OPV cells. The results indicate that, in the case of metal ABL, a good matching between the work function of the anode and the highest occupied molecular orbital of the donor material is the major factor limiting the hole transfer efficiency. Indeed, gold is efficient as ABL only when the HOMO of the organic donor is close to its work function ?Au. MoO3 has a wider field of application as ABL than gold. The role of the oxide is not so clearly understood than that of Au, different models proposed to interpret the experimental results are discussed.

Bernède, J.-C.; Nguyen, D.-T.; Cattin, L.; Morsli, M.; Kanth, S. R. B.; Patil, S.

2011-12-01

64

Performance of dye-sensitized solar cells with various carbon nanotube counter electrodes  

Microsoft Academic Search

Double-wall carbon nanotubes (DWCNTs), single-wall carbon nanotubes (SWCNTs), and multi-wall carbon nanotubes (MWCNTs) were\\u000a investigated as an alternative for platinum in counter-electrodes for dye-sensitized solar cells. The counter-electrodes were\\u000a prepared on fluorine-doped tin oxide glass substrates by the screen printing technique from pastes of carbon nanotubes and\\u000a organic binder. The solar cells were assembled from carbon nanotubes counter-electrodes and screen

Dingwen Zhang; Xiaodong Li; Si Chen; Zhuo Sun; Xi Jiang Yin; Sumei Huang

2011-01-01

65

A tough and high-performance transparent electrode from a scalable and transfer-free method.  

PubMed

Conductive metal films are patterned into transparent metal nanowire networks by using electrospun fibers as a mask. Both the transmittance and sheet resistance (6 ?/? at 83% transmittance and 24 ?/? at 92% transmittance) of the metal nanowire-based electrode out-perform commercial indium doped tin oxide (ITO) electrodes. The metal nanowire-based transparent electrodes were fabricated on both rigid glass and flexible polyethylene terephthalate (PET) substrates. In addition to state of art performance, the transparent electrodes also exhibit outstanding toughness. They can withstand repeated scotch tape peeling and various bending tests. The method for making the metal nanowire is scalable, and a touch screen on flexible substrate is demonstrated. PMID:24773271

He, Tianda; Xie, Aozhen; Reneker, Darrell H; Zhu, Yu

2014-05-27

66

Carbon nanotube counter electrode for high-efficient fibrous dye-sensitized solar cells  

PubMed Central

High-efficient fibrous dye-sensitized solar cell with carbon nanotube (CNT) thin films as counter electrodes has been reported. The CNT films were fabricated by coating CNT paste or spraying CNT suspension solution on Ti wires. A fluorine tin oxide-coated CNT underlayer was used to improve the adherence of the CNT layer on Ti substrate for sprayed samples. The charge transfer catalytic behavior of fibrous CNT/Ti counter electrodes to the iodide/triiodide redox pair was carefully studied by electrochemical impedance and current-voltage measurement. The catalytic activity can be enhanced by increasing the amount of CNT loading on substrate. Both the efficiencies of fibrous dye-sensitized solar cells using paste coated and sprayed CNT films as counter electrodes are comparative to that using Pt wires, indicating the feasibility of CNT/Ti wires as fibrous counter electrode for superseding Pt wires.

2012-01-01

67

Carbon nanotube counter electrode for high-efficient fibrous dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

High-efficient fibrous dye-sensitized solar cell with carbon nanotube (CNT) thin films as counter electrodes has been reported. The CNT films were fabricated by coating CNT paste or spraying CNT suspension solution on Ti wires. A fluorine tin oxide-coated CNT underlayer was used to improve the adherence of the CNT layer on Ti substrate for sprayed samples. The charge transfer catalytic behavior of fibrous CNT/Ti counter electrodes to the iodide/triiodide redox pair was carefully studied by electrochemical impedance and current-voltage measurement. The catalytic activity can be enhanced by increasing the amount of CNT loading on substrate. Both the efficiencies of fibrous dye-sensitized solar cells using paste coated and sprayed CNT films as counter electrodes are comparative to that using Pt wires, indicating the feasibility of CNT/Ti wires as fibrous counter electrode for superseding Pt wires.

Huang, Shuqing; Sun, Huicheng; Huang, Xiaoming; Zhang, Quanxin; Li, Dongmei; Luo, Yanhong; Meng, Qingbo

2012-04-01

68

Gold nanoparticle decorated multi-walled carbon nanotubes as counter electrode for dye sensitized solar cells.  

PubMed

A novel counter electrode material for dye sensitized solar cells (DSSCs) composed of nanostructured Au particles decorated on functionalized multi-walled carbon nanotubes (f-MWNTs) is demonstrated for the first time. MWNTs synthesized by catalytic chemical vapor deposition technique are purified and functionalized by treating with concentrated acids. Au nanoparticles are decorated on f-MWNTs by a rapid and facile microwave assisted polyol reduction method. The materials are characterized by X-ray diffractometry, Fourier transform infra red spectroscopy and electron microscopy. The DSSC fabricated with Au/f-MWNTs based counter electrode shows enhanced power conversion efficiency (eta) of 4.9% under AM 1.5G simulated solar radiation. In comparison, the reference DSSCs fabricated with f-MWNTs and Pt counter electrodes show eta of 2.1% and 4.5%. This high performance of Au/f-MWNTs counter electrode is investigated using electrochemical impedance spectroscopy and cyclic voltammetry studies. PMID:23421212

Kaniyoor, Adarsh; Ramaprabhu, Sundara

2012-11-01

69

Graphene nanosheet counter-electrodes for dye-sensitized solar cells  

Microsoft Academic Search

Graphene nanosheets (GNs) have been investigated as a counter electrode for dye-sensitized solar cells (DSCs). Mesoporous TiO2 films are prepared from the commercial TiO2 nano-powders by screen-printing technique on fluorine-doped tin oxide (FTO) slides. GNs are applied to substitute for platinum as counter-electrode materials. GN films are screen printed on FTO glass using a paste based on GNs dispersed in

D. W. Zhang; X. D. Li; S. Chen; H. B. Li; Z. Sun; X. J. Yin; S. M. Huang

2010-01-01

70

Micro coulter counters with platinum black electroplated electrodes for human blood cell sensing  

Microsoft Academic Search

We demonstrated a novel micro Coulter counter featuring platinum-black electrodes for human blood cell counting application.\\u000a Two designs of micro Coulter counter were fabricated using two distinct technologies: integrated parylene and soft lithography.\\u000a Platinum-black enhanced detection in the intermediate frequency range (?100 Hz to 7 MHz), which is the operation frequency\\u000a suitable for sensing the cells flowing by the electrodes. A detailed

Siyang Zheng; Mike Liu; Yu-Chong Tai

2008-01-01

71

Passivation coating on electrospun copper nanofibers for stable transparent electrodes.  

PubMed

Copper nanofiber networks, which possess the advantages of low cost, moderate flexibility, small sheet resistance, and high transmittance, are one of the most promising candidates to replace indium tin oxide films as the premier transparent electrode. However, the chemical activity of copper nanofibers causes a substantial increase in the sheet resistance after thermal oxidation or chemical corrosion of the nanofibers. In this work, we utilize atomic layer deposition to coat a passivation layer of aluminum-doped zinc oxide (AZO) and aluminum oxide onto electrospun copper nanofibers and remarkably enhance their durability. Our AZO-copper nanofibers show resistance increase of remarkably only 10% after thermal oxidation at 160 °C in dry air and 80 °C in humid air with 80% relative humidity, whereas bare copper nanofibers quickly become insulating. In addition, the coating and baking of the acidic PEDOT:PSS layer on our fibers increases the sheet resistance of bare copper nanofibers by 6 orders of magnitude, while the AZO-Cu nanofibers show an 18% increase. PMID:22548313

Hsu, Po-Chun; Wu, Hui; Carney, Thomas J; McDowell, Matthew T; Yang, Yuan; Garnett, Erik C; Li, Michael; Hu, Liangbing; Cui, Yi

2012-06-26

72

Nanostructured electrochromic films by inkjet printing on large area and flexible transparent silver electrodes.  

PubMed

Printed electrochromic flexible films were obtained by combining transparent silver grid electrodes formed by self-assembly and inkjet printed WO3 nanoparticles. Concentrated dispersions of WO3 nanoparticles were inkjet printed on transparent plastic silver grid electrodes with a high transparency of 83% in the spectral range of 400-800 nm, and a low sheet resistance in the range of 1-5 ? sq(-1). These electrodes were used for electrochromic applications for the first time. The resultant patterned nanostructured electrochromic films maintained their coloring and bleaching performance after bending of the flexible films. PMID:24676234

Layani, Michael; Darmawan, Peter; Foo, Wan Ling; Liu, Liang; Kamyshny, Alexander; Mandler, Daniel; Magdassi, Schlomo; Lee, Pooi See

2014-04-10

73

Conducting polymers based counter electrodes for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Conducting polymer films were synthesized and employed as an alternative to expensive platinum counter electrodes for dye-sensitized solar cells. poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) thin films were spin-coated and polypyrrole films were electrochemically deposited via cyclic voltammetry method on ITO substrates. The morphology of the films were imaged by SEM and AFM. These films show good catalytic activity towards triiodide reduction as compared to Pt/FTO electrodes. Finally the photovoltaic performance of DSSC fabricated using N3 dye were compared with PT/FTO, PEDOT/ITO, and e-PPy counter electrodes.

Veerender, P.; Saxena, Vibha; Gusain, Abhay; Jha, P.; Koiry, S. P.; Chauhan, A. K.; Aswal, D. K.; Gupta, S. K.

2014-04-01

74

Transparent and stretchable high-performance supercapacitors based on wrinkled graphene electrodes.  

PubMed

Transparent and/or stretchable energy storage devices have attracted intense attention due to their unique optical and/or mechanical properties as well as their intrinsic energy storage function. However, it remains a great challenge to integrate transparent and stretchable properties into an energy storage device because the currently developed electrodes are either transparent or stretchable, but not both. Herein, we report a simple method to fabricate wrinkled graphene with high stretchability and transparency. The resultant wrinkled graphene sheets were used as both current collector and electrode materials to develop transparent and stretchable supercapacitors, which showed a high transparency (57% at 550 nm) and can be stretched up to 40% strain without obvious performance change over hundreds of stretching cycles. PMID:24350978

Chen, Tao; Xue, Yuhua; Roy, Ajit K; Dai, Liming

2014-01-28

75

Direct synthesis of platelet graphitic-nanofibres as a highly porous counter-electrode in dye-sensitized solar cells.  

PubMed

We synthesized platelet graphitic-nanofibres (GNFs) directly onto FTO glass and applied this forest of platelet GNFs as a highly porous structural counter-electrode in dye-sensitized solar cells (DSSCs). We investigated the electrochemical properties of counter-electrodes made from the highly porous structural GNFs and the photoconversion performance of the cells made with these electrodes. PMID:22354284

Hsieh, Chien-Kuo; Tsai, Ming-Chi; Yen, Ming-Yu; Su, Ching-Yuan; Chen, Kuei-Fu; Ma, Chen-Chi M; Chen, Fu-Rong; Tsai, Chuen-Horng

2012-03-28

76

Electrode with transparent series resistance for uniform switching of optical modulation devices  

Microsoft Academic Search

Switching uniformity of an optical modulation device for controlling the propagation of electromagnetic radiation is improved by use of an electrode comprising an electrically resistive layer that is transparent to the radiation. The resistive layer is preferably an innerlayer of a wide-bandgap oxide sandwiched between layers of indium tin oxide or another transparent conductor, and may be of uniform thickness,

D. Morgan Tench; Michael A. Cunningham; Paul H. Kobrin

2008-01-01

77

Nanostructured electrochromic films by inkjet printing on large area and flexible transparent silver electrodes  

NASA Astrophysics Data System (ADS)

Printed electrochromic flexible films were obtained by combining transparent silver grid electrodes formed by self-assembly and inkjet printed WO3 nanoparticles. Concentrated dispersions of WO3 nanoparticles were inkjet printed on transparent plastic silver grid electrodes with a high transparency of 83% in the spectral range of 400-800 nm, and a low sheet resistance in the range of 1-5 ? sq-1. These electrodes were used for electrochromic applications for the first time. The resultant patterned nanostructured electrochromic films maintained their coloring and bleaching performance after bending of the flexible films.Printed electrochromic flexible films were obtained by combining transparent silver grid electrodes formed by self-assembly and inkjet printed WO3 nanoparticles. Concentrated dispersions of WO3 nanoparticles were inkjet printed on transparent plastic silver grid electrodes with a high transparency of 83% in the spectral range of 400-800 nm, and a low sheet resistance in the range of 1-5 ? sq-1. These electrodes were used for electrochromic applications for the first time. The resultant patterned nanostructured electrochromic films maintained their coloring and bleaching performance after bending of the flexible films. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr06890k

Layani, Michael; Darmawan, Peter; Foo, Wan Ling; Liu, Liang; Kamyshny, Alexander; Mandler, Daniel; Magdassi, Schlomo; Lee, Pooi See

2014-04-01

78

Silicon Pedot-Pss Nanocomposite as AN Efficient Counter Electrode for Dye-Sensitized Solar Cells  

NASA Astrophysics Data System (ADS)

A novel inorganic/organic nanocomposite film composed of Si nanoparticles (NPs) and poly-(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) is obtained from a simple mechanical mixture of Si NPs powder and aqueous PEDOT-PSS solution. Employing this composite film as a counter electrode, dye-sensitized solar cell (DSSC) exhibits an efficiency of 5.7% and a fill factor of 0.51, which are much higher than these of DSSC using pristine PEDOT-PSS electrode (2.9% and 0.25, respectively). The improvements in the photovoltaic performance of the former are primarily derived from improved electrocatalytic performance of the electrode, as evidenced by electrochemical measurements, the composite electrode has lower impedance and higher electrocatalytic activity when in comparison with pristine PEDOT-PSS electrode. These improvements are primarily deriving from the increased electrochemical surface by the addition of Si NPs. The characteristics of Si NPs/PEDOT-PSS composite counter electrode reveal its potential for the use of low-cost and stable Pt-free counter electrode materials. In addition, the results achieved in this work also provide a facile and efficient approach to improve the photovoltaic performance of DSSCs using PEDOT-PSS electrodes.

Song, Dandan; Li, Meicheng; Bai, Fan; Li, Yingfeng; Jiang, Yongjian; Jiang, Bing

2013-08-01

79

Fabrication and characterization of carbon-based counter electrodes prepared by electrophoretic deposition for dye-sensitized solar cells  

PubMed Central

Three different carbon-based counter electrodes are investigated in light of catalytic activities such as electrochemical frequencies and interface impedances. We fabricated carbon-based counter electrodes of dye-sensitized solar cells [DSSCs] using graphene, single-walled carbon nanotubes [SWNTs], and graphene-SWNT composites by electrophoretic deposition method. We observed the optical and electrochemical properties of the carbon-based counter electrodes. The DSSC with the graphene-deposited counter electrode demonstrated the best conversion efficiency of 5.87% under AM 1.5 and 1 sun condition. It could be utilized for a low-cost and high-throughput process for DSSCs.

2012-01-01

80

Uniform self-forming metallic network as a high-performance transparent conductive electrode.  

PubMed

A transparent, conductive, and flexible electrode is demonstrated. It is based on an inexpensive and easily manufacturable metallic network formed by depositing metals onto a template film. This electrode shows excellent electro-optical properties, with the figure of merit ranging from 300 to 700, and transmittance from 82% (~4.3 ? sq(-1) ) to 45% (~0.5 ? sq(-1) ). PMID:24510662

Han, Bing; Pei, Ke; Huang, Yuanlin; Zhang, Xiaojian; Rong, Qikun; Lin, Qinggeng; Guo, Yangfei; Sun, Tianyi; Guo, Chuanfei; Carnahan, David; Giersig, Michael; Wang, Yang; Gao, Jinwei; Ren, Zhifeng; Kempa, Krzysztof

2014-02-12

81

Different hierarchical nanostructured carbons as counter electrodes for CdS quantum dot solar cells.  

PubMed

CdS quantum dot sensitized solar cells based on TiO(2) photoanode and nanostructured carbon as well as Pt as counter electrodes using iodide/triiodide and polysulfide electrolytes were fabricated to improve the efficiency and reduce the cost of solar cells. Compared with conventional Pt (? = 1.05%) and CMK-3 (? = 0.67%) counter electrodes, hollow core-mesoporous shell carbon (HCMSC) counter electrode using polysulfide electrolyte exhibits much larger incident photon to current conversion efficiency (IPCE = 27%), photocurrent density (J(sc) = 4.31 mA.cm(-2)) and power conversion efficiency (? = 1.08%), which is basically due to superb structural characters of HCMSC such as large specific surface area, high mesoporous volume, and 3D interconnected well-developed hierarchical porosity network, which facilitate fast mass transfer with less resistance and enable HCMSC to have highly enhanced catalytic activity toward the reduction of electrolyte shuttle. PMID:22132833

Paul, Gouri Sankar; Kim, Jung Ho; Kim, Min-Sik; Do, Kwangseok; Ko, Jaejung; Yu, Jong-Sung

2012-01-01

82

Electrochemically Reduced Graphene Oxide Multilayer Films as Efficient Counter Electrode for Dye-Sensitized Solar Cells  

PubMed Central

We report on a new counter electrode for dye-sensitized solar cells (DSCs), which is prepared using layer-by-layer assembly of negatively charged graphene oxide and positively charged poly (diallyldimethylammonium chloride) followed by an electrochemical reduction procedure. The DSC devises using the heteroleptic Ru complex C106TBA as sensitizer and this new counter electrode reach power conversion efficiencies of 9.5% and 7.6% in conjunction with low volatility and solvent free ionic liquid electrolytes, respectively. The new counter electrode exhibits good durability (60°C for 1000?h in a solar simulator, 100?mW cm?2) during the accelerated tests when used in combination with an ionic liquid electrolyte. This work identifies a new class of electro-catalysts with potential for low cost photovoltaic devices.

Xu, Xiaobao; Huang, Dekang; Cao, Kun; Wang, Mingkui; Zakeeruddin, Shaik M.; Gratzel, Michael

2013-01-01

83

Electrochemically reduced graphene oxide multilayer films as efficient counter electrode for dye-sensitized solar cells.  

PubMed

We report on a new counter electrode for dye-sensitized solar cells (DSCs), which is prepared using layer-by-layer assembly of negatively charged graphene oxide and positively charged poly (diallyldimethylammonium chloride) followed by an electrochemical reduction procedure. The DSC devises using the heteroleptic Ru complex C106TBA as sensitizer and this new counter electrode reach power conversion efficiencies of 9.5% and 7.6% in conjunction with low volatility and solvent free ionic liquid electrolytes, respectively. The new counter electrode exhibits good durability (60°C for 1000?h in a solar simulator, 100?mW cm(-2)) during the accelerated tests when used in combination with an ionic liquid electrolyte. This work identifies a new class of electro-catalysts with potential for low cost photovoltaic devices. PMID:23508212

Xu, Xiaobao; Huang, Dekang; Cao, Kun; Wang, Mingkui; Zakeeruddin, Shaik M; Grätzel, Michael

2013-01-01

84

Electrochemical and Optical Evaluation of Noble Metal-and Carbon-ITO Hybrid Optically Transparent Electrodes  

SciTech Connect

Optically transparent hybrid electrodes were constructed by sputtering or thermally evaporating layers of varying thickness of Au, Pd, Pt, or C onto an existing conductive indium-tin oxide (ITO) layer on glass. These electrodes were characterized using UV-Vis spectroscopy and cyclic voltammetry; redox probes examined were potassium ferricyanide, tris-(2, 2'-bipyridyl)ruthenium(II) chloride, hydroquinone, and para-aminophenol (PAP). Each type of hybrid was evaluated and compared with other hybrids, as well as with bare ITO electrodes and commercially available Au, Pt, and glassy carbon disk electrodes. Our results indicated that these hybrid electrodes are reasonably robust, easy to prepare, and extend the capabilities of bare ITO surfaces with respect to the electrochemical response (especially for organic redox probes), while giving up little in the way of optical transparency. Because of these characteristics, hybrid electrodes should be especially suited to many spectroelectrochemical applications.

Zudans, Imants; Paddock, Jean R.; Kuramitz, Hideki; Maghasi, Anne T.; Wansapura, Chamika M.; Conklin, Sean D.; Kaval, Necati; Shtoyko, Tanya; Monk, David J.; Bryan, Samuel A.; Hubler, Timothy L.; Richardson, John N.; Seliskar, Carl J.; Heineman, William R.

2004-04-15

85

Ordered mesoporous tungsten suboxide counter electrode for highly efficient iodine-free electrolyte-based dye-sensitized solar cells.  

PubMed

A disulfide/thiolate (T(2)/T(-)) redox-couple electrolyte, which is a promising iodine-free electrolyte owing to its transparent and noncorrosive properties, requires alternative counter-electrode materials because conventional Pt shows poor catalytic activity in such an electrolyte. Herein, ordered mesoporous tungsten suboxide (m-WO(3-x)), synthesized by using KIT-6 silica as a hard template followed by a partial reduction, is used as a catalyst for a counter electrode in T(2)/T(-)-electrolyte-based dye-sensitized solar cells (DSCs). The mesoporous tungsten suboxide, which possesses interconnected pores of 4 and 20 nm, provides a large surface area and efficient electrolyte penetration into the m-WO(3-x) pores. In addition to the advantages conferred by the mesoporous structure, partial reduction of tungsten oxide creates oxygen vacancies that can function as active catalytic sites, which causes a high electrical conductivity because of intervalence charge transfer between the W(5+) and W(6+) ions. m-WO(3-x) shows a superior photovoltaic performance (79 % improvement in the power conversion efficiency) over Pt in the T(2)/T(-) electrolyte. The superior catalytic activity of m-WO(3-x) is investigated by using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel polarization curve analysis. PMID:23281317

Jeong, Inyoung; Jo, Changshin; Anthonysamy, Arockiam; Kim, Jung-Min; Kang, Eunae; Hwang, Jongkook; Ramasamy, Easwaramoorthi; Rhee, Shi-Woo; Kim, Jin Kon; Ha, Kyoung-Su; Jun, Ki-Won; Lee, Jinwoo

2013-02-01

86

Light energy conversion with pheophytin a and chlorophyll a monolayers at the optical transparent electrode  

Microsoft Academic Search

The photoelectrochemical behavior of chlorophyll (alpha) and pheophytin (alpha) monolayers, deposited on SnO2 optically transparent electrodes by means of the Langmuir-Blodgett technique, has been investigated. Spectra of photocurrents coincided with the absorption spectra of photosynthetic pigment monolayers at the SnO2-solution interfaces. The anodic and cathodic photocurrents were measured at different electrode potentials. The effects of solution pH, electrode potentials and

Roger M. Leblanc; P.-F. Blanchet; D. Cote; M. I. Gugeshashvili; G. Munger; Alexander G. Volkov

1991-01-01

87

Effects of transparent electrode resistance on the performance characteristics of electrochemichromic cells  

SciTech Connect

The performance characteristics of WO/sub 3/ electrochemichromic cells have been studied in connection with the electrical resistance of transparent electrodes and a lumped resistor connected to the electrodes in series. The sheet resistance of transparent electrodes used and the resistance of lumped resistor used are in the range of 10--1250 ..cap omega../D'Alembertian and 10--2500 ..cap omega.., respectively. The thickness of the WO/sub 3/ film is --2400 A-circle or --4300 A-circle, and the electrolyte is 1 N H/sub 2/SO/sub 4/ aqueous solution containing 10 vol % glycerol. The current pulse form and the change in optical transmittance of experimental cells under operation were observed, and the operating characteristics of electrochemichromic cells have been found to clearly depend on the sheet resistance of transparent electrodes and/or the resistance of a lumped resistor connected serially.

Kaneko, H.; Miyake, K.

1986-07-14

88

Engineered porous silicon counter electrodes for high efficiency dye-sensitized solar cells.  

PubMed

In this work, we demonstrate for the first time, the use of porous silicon (P-Si) as counter electrodes in dye-sensitized solar cells (DSSCs) with efficiencies (5.38%) comparable to that achieved with platinum counter electrodes (5.80%). To activate the P-Si for triiodide reduction, few layer carbon passivation is utilized to enable electrochemical stability of the silicon surface. Our results suggest porous silicon as a promising sustainable and manufacturable alternative to rare metals for electrochemical solar cells, following appropriate surface modification. PMID:24884149

Erwin, William R; Oakes, Landon; Chatterjee, Shahana; Zarick, Holly F; Pint, Cary L; Bardhan, Rizia

2014-06-25

89

Counter electrode based on an ion-exchanger Donnan exclusion membrane for bioelectroanalysis.  

PubMed

Ion-exchanger based Donnan exclusion membranes (IEDEM) are studied here as separators for counter and pseudo-reference electrodes in bioelectroanalysis. Since the potential across the membrane remains indifferent for a wide range of current densities in contact with electrolyte solutions, IEDEM behave as ideally non-polarizable membranes. Consequently, such membranes may be suitable with counter or reference electrode, depending on the adopted cell configuration (three- or two-electrode system). Four configurations were characterized in order to establish the limitations of commercial anion-exchanging membranes, using chronopotentiometry as readout protocol. Three- and two-electrode configurations with and without membrane exhibited similar characteristics in terms of drift and reproducibility (observed drift and RSD were 0.0007s(1/2) per scan number and 1.71%, respectively). Several currents amplitudes were applied to evaluate the upper current limits for the membranes, which was found at about 10mA [42.8mAcm(-2)]. This value is significantly above those typically used in chronopotentiometric experiments, which involve hundreds of ?A. Three different analytes were measured in human whole blood using an IEDEM as a counter electrode. A divalent cation (calcium), a polyion (protamine), and an anion (chloride) were successfully determined in blood and compared to reference methods. Finally, the obtained results suggest that such membranes may be used in bioelectrochemical sensing approaches to replace expensive but less appropriate electrode materials for the measurement in matrices that contain lipids and proteins. PMID:24858674

Ghahraman Afshar, Majid; Crespo, Gastón A; Bakker, Eric

2014-11-15

90

Optically Transparent Thin-Layer Electrodes: Ninhydrin Reduction in an Infrared Transparent Cell.  

National Technical Information Service (NTIS)

The construction and application of an infrared transparent thin-layer electrochemical cell are described. The properties of large optical thickness and small diffusional thickness are combined in the cell by use of multiple, spacer-separated gold minigri...

W. R. Heineman J. N. Burnett R. W. Murray

1968-01-01

91

Organic light-emitting diodes on solution-processed graphene transparent electrodes.  

PubMed

Theoretical estimates indicate that graphene thin films can be used as transparent electrodes for thin-film devices such as solar cells and organic light-emitting diodes, with an unmatched combination of sheet resistance and transparency. We demonstrate organic light-emitting diodes with solution-processed graphene thin film transparent conductive anodes. The graphene electrodes were deposited on quartz substrates by spin-coating of an aqueous dispersion of functionalized graphene, followed by a vacuum anneal step to reduce the sheet resistance. Small molecular weight organic materials and a metal cathode were directly deposited on the graphene anodes, resulting in devices with a performance comparable to control devices on indium-tin-oxide transparent anodes. The outcoupling efficiency of devices on graphene and indium-tin-oxide is nearly identical, in agreement with model predictions. PMID:19902961

Wu, Junbo; Agrawal, Mukul; Becerril, Héctor A; Bao, Zhenan; Liu, Zunfeng; Chen, Yongsheng; Peumans, Peter

2010-01-26

92

Hydrogen Exfoliated Graphene As Counter Electrode for Dye Sensitized Solar Cells  

Microsoft Academic Search

In the present work, we demonstrate the use of few layered Graphene sheets (HEG) synthesized by hydrogen induced exfoliation technique as a novel counter electrode material for dye sensitized solar cells (DSSCs). The presence of wrinkles and low oxygen content gives a high surface area and good electrical conductivity to HEG, making it superior to other graphenes. Electrochemical impedance spectroscopy

Adarsh Kaniyoor; Sundara Ramaprabhu

2011-01-01

93

Hierarchical Porous Carbon Counter Electrode for Dye-Sensitized Solar Cells  

Microsoft Academic Search

Hierarchical porous carbon is prepared by a combination of self-organization and chemical activation and explored as counter electrode for dye-sensitized solar cells. Pore structure analysis shows that micropores generated within the mesopore wall and the pristine mesopore structure of mesoporous carbon are preserved during KOH activation. Electrochemical impedance spectroscopy studies demonstrate a relatively high electrocatalytic activity of hierarchical porous carbon

Gui-Qiang Wang; Cong-Cong Huang; Wei Xing; Shu-Ping Zhuo

2011-01-01

94

Carbon nanotube and graphene hybrid thin film for transparent electrodes and field effect transistors.  

PubMed

Single-walled carbon nanotubes and graphene hybrid films with complementary properties are combined for use in high-performance transparent electrodes and field-effect transistors (FETs). Based on the transfer characteristics for the hybrid film-based FETs, an improved Ion /Ioff and on-state current are achieved, compared with pristine graphene. Notably, the hybrid film has a sheet resistance of 300 ?/sq with 96.4% transparency. PMID:24733505

Kim, Sung Ho; Song, Wooseok; Jung, Min Wook; Kang, Min-A; Kim, Kiwoong; Chang, Sung-Jin; Lee, Sun Sook; Lim, Jongsun; Hwang, Jinha; Myung, Sung; An, Ki-Seok

2014-07-01

95

30 inch Roll-Based Production of High-Quality Graphene Films for Flexible Transparent Electrodes  

Microsoft Academic Search

We report that 30-inch scale multiple roll-to-roll transfer and wet chemical doping considerably enhance the electrical properties of the graphene films grown on roll-type Cu substrates by chemical vapor deposition. The resulting graphene films shows a sheet resistance as low as ~30 Ohm\\/sq at ~90 % transparency which is superior to commercial transparent electrodes such as indium tin oxides (ITO).

Sukang Bae; Hyeong Keun Kim; Youngbin Lee; Xianfang Xu; Jae-Sung Park; Yi Zheng; Jayakumar Balakrishnan; Danho Im; Tian Lei; Young Il Song; Young Jin Kim; Kwang S. Kim; Barbaros Özyilmaz; Jong-Hyun Ahn; Byung Hee Hong; Sumio Iijima

2009-01-01

96

Nanoimprinted transparent metal electrodes and their applications in organic optoelectronic devices  

NASA Astrophysics Data System (ADS)

A new type of transparent and conductive electrode (TCE) in the form of nanoscale periodically perforated metal mesh film by nanoimprint lithography (NIL) has been developed. The developed transparent metal electrodes have the characteristics of high optical transmittance and electrical conductivity, a combination of properties that makes them suitable as a replacement for indium-doped tin oxide (ITO), a predominant choice as a TCE for organic optoelectronic device applications. Not only do metals provide different work functions, but also nanoscale metallic gratings exhibit unique optical properties due to the excitation of surface plasmon resonance (SPR), which can be exploited in specially designed solar cells to achieve enhanced light absorption. The future low-cost and high performance organic optoelectronic devices will need a TCE which should be available with low-cost and high mechanical stability, the properties which ITO does not have. This work shows that transparent metal (e.g. Cu) electrodes on flexible plastic substrates exhibit not only high transmittance and conductivity, but also a superior mechanical strength to compared ITO electrode. Organic light emitting diodes (OLEDs) and Organic solar cells (OSCs) have been demonstrated using transparent metal (Au, Ag, and Cu) electrodes as a TCE on both hard (glass) and soft (PET) substrates and showed comparable performance to the device using conventional ITO electrode. To demonstrate the possibility of PCE enhancement of OSCs using developed metal electrode, OSCs have been fabricated with a periodic (220 nm) Ag grating electrode, acting as not only a transparent electrode but also to support surface plasmon modes with localized and concentrated light distribution. Absolute PCE enhancement of about 35% for the device with Ag electrode relative to the ITO device was achieved. It has also been demonstrated that the SPR enhances the external quantum efficiency (EQE) by about 2.5 times for the Ag device compared to the ITO device. The experimental results suggested that higher enhancement would be possible for a thinner organic layer. Therefore, the use of transparent metal electrode as a TCE instead of ITO could help to realize low-cost, high performance large area flexible organic optoelectronic devices such as OSCs and OLEDs.

Kang, Myung-Gyu

97

Interfacial engineering of ultrathin metal film transparent electrode for flexible organic photovoltaic cells.  

PubMed

A generally applicable method has been developed for fabricating highly transparent ultrathin Ag films on both glass and plastic substrates using the self-assembled monolayer modified ZnO/Ag/ZnO tri-layer structure. The resulting films show remarkably low surface roughness with very high transparency (>80% between 400 and 600 nm) and low surface resistance (8.61 ?/?). With an inverted architecture, the devices based on the SAM modified tri-layer UTMF electrode show superior performance and mechanical properties than those using ITO electrode on both glass and plastic substrates. PMID:24623553

Zou, Jingyu; Li, Chang-Zhi; Chang, Chih-Yu; Yip, Hin-Lap; Jen, Alex K-Y

2014-06-01

98

Electrode with transparent series resistance for uniform switching of optical modulation devices  

DOEpatents

Switching uniformity of an optical modulation device for controlling the propagation of electromagnetic radiation is improved by use of an electrode comprising an electrically resistive layer that is transparent to the radiation. The resistive layer is preferably an innerlayer of a wide-bandgap oxide sandwiched between layers of indium tin oxide or another transparent conductor, and may be of uniform thickness, or may be graded so as to provide further improvement in the switching uniformity. The electrode may be used with electrochromic and reversible electrochemical mirror (REM) smart window devices, as well as display devices based on various technologies.

Tench, D. Morgan (Camarillo, CA); Cunningham, Michael A. (Thousand Oaks, CA); Kobrin, Paul H. (Newbury Park, CA)

2008-01-08

99

Ultra-Thin Optically Transparent Carbon Electrodes Produced from Layers of Adsorbed Proteins  

PubMed Central

This work describes a simple, versatile, and inexpensive procedure to prepare optically transparent carbon electrodes, using proteins as precursors. Upon adsorption, the protein-coated substrates were pyrolyzed under reductive conditions (5% H2) to form ultra-thin, conductive electrodes. Because proteins spontaneously adsorb to interfaces forming uniform layers, the proposed method does not require a precise control of the preparation conditions, specialized instrumentation, or expensive precursors. The resulting electrodes were characterized by a combination of electrochemical, optical, and spectroscopic means. As a proof-of-concept, the optically-transparent electrodes were also used as substrate for the development of an electrochemical glucose biosensor. The proposed films represent a convenient alternative to more sophisticated, and less available, carbon-based nanomaterials. Furthermore, these films could be formed on a variety of substrates, without classical limitations of size or shape.

Alharthi, Sarah A.; Benavidez, Tomas E.; Garcia, Carlos D.

2013-01-01

100

Graphene transparent and conductive electrode for light harvesting solar cells  

Microsoft Academic Search

Transparent and conductive coatings were achieved on glass by dissolving graphene oxide into dionized water followed by spray-coating on preheated substrate, chemical and thermal reduction. SEM shows the spray-coating graphene oxide coatings and the reduced graphene oxide coatings are uniform. No obvious aggregation was observed. UV-vis transmission spectra shows 65% transmittance at 550 nm of the graphene coatings with 15

Wei Zhou; Amare Benor Belay; Kris Davis; Rodica Khugler; Nicoleta Sorloaica-Hickman

2011-01-01

101

Toward Low-Cost, High-Efficiency, and Scalable Organic Solar Cells with Transparent Metal Electrode and Improved Domain Morphology  

Microsoft Academic Search

We review our recent progress toward realizing future low-cost, high-efficiency, and scalable organic solar cells (OSCs). First, we show that the transparent electrodes based on metallic nanostructure is a strong candidate as a replacement of conventional indium tin oxide (ITO) electrode due to their superior properties, such as high optical transparency, good electrical conductivity, and mechanical flexibility, and the versatility

Myung-Gyu Kang; Hui Joon Park; Se Hyun Ahn; Ting Xu; L. Jay Guo

2010-01-01

102

Flexible, transparent single-walled carbon nanotube transistors with graphene electrodes  

Microsoft Academic Search

This paper reports a mechanically flexible, transparent thin film transistor that uses graphene as a conducting electrode and single-walled carbon nanotubes (SWNTs) as a semiconducting channel. These SWNTs and graphene films were printed on flexible plastic substrates using a printing method. The resulting devices exhibited a mobility of ~ 2 cm2 V - 1 s - 1, On\\/Off ratio of

Sukjae Jang; Houk Jang; Youngbin Lee; Daewoo Suh; Seunghyun Baik; Byung Hee Hong; Jong-Hyun Ahn

2010-01-01

103

Few layers of graphene as transparent electrode from botanical derivative camphor  

Microsoft Academic Search

Here, we report synthesis of large area graphene sheets by control pyrolysis of solid botanical derivative camphor (C10H16O) and fabrication of transparent electrodes. Raman study shows highly ordered graphene sheet with minimum defects. Second order Raman spectrum shows that graphene layers are more than single layer and can be controlled with amount of camphor pyrolyzed. Transmission electron microscopic images show

Golap Kalita; Matsushima Masahiro; Hideo Uchida; Koichi Wakita; Masayoshi Umeno

2010-01-01

104

Technology ready use of single layer graphene as a transparent electrode for hybrid photovoltaic devices  

Microsoft Academic Search

Graphene has been used recently as a replacement for indium tin oxide (ITO) for the transparent electrode of an organic photovoltaic device. Due to its limited supply, ITO is considered as a limiting factor for the commercialization of organic solar cells. We explored the use of large-area graphene grown on copper by chemical vapor deposition (CVD) and then transferred to

Zhibing Wang; Conor P. Puls; Neal E. Staley; Yu Zhang; Aaron Todd; Jian Xu; Casey A. Howsare; Matthew J. Hollander; Joshua A. Robinson; Ying Liu

2011-01-01

105

Utilization of graphene electrode in transparent microwell arrays for high throughput cell trapping and lysis.  

PubMed

Here we present a high-throughput, transparent microfluidic device with embedded microwell arrays sandwiched between transparent electrodes made from graphene (at the bottom) and indium tin oxide (at the top) for dielectrophoretic cell trapping and electrical lysis. Graphene suppresses unwanted faradaic reaction effects on the cells and the medium that is typically observed in ITO based electrodes from application of DC field for electrical lysis. This is because graphene is more electrochemically inert than indium tin oxide (ITO) where ITO undergoes reduction-oxidation (redox) reaction in the presence of electrolyte in most standard cell media. This redox process also compromises ITO's electrical properties and optical transparency over multiple use. The presented microfluidic device shows high efficiency for cell trapping and lysis and an electrochemically stable behavior for long operational life. PMID:24967752

Ameri, S Kabiri; Singh, P K; Sonkusale, S

2014-11-15

106

Self-assembled monolayer of graphene/Pt as counter electrode for efficient dye-sensitized solar cell.  

PubMed

Monolayer of PDDA/graphene/PDDA/H(2)PtCl(6) is fabricated on conductive glass using electrostatic layer-by-layer self-assembly technique, which is then converted to graphene/Pt monolayer for use as counter electrode in dye-sensitized solar cell (DSSC). As compared to the sputtered Pt counter electrode, the self-assembled monolayer reduces the Pt amount by about 1000-fold but exhibits comparable photovoltaic performance. This finding provides a new route to fabrication of cheap and efficient counter electrodes for flow-line production of DSSCs. PMID:21909512

Gong, Feng; Wang, Hong; Wang, Zhong-Sheng

2011-10-21

107

Scalable Low-Cost SnS2 Nanosheets as Counter Electrode Building Blocks for Dye-Sensitized Solar Cells.  

PubMed

A new type of semitransparent SnS2 nanosheet (NS) films were synthesized using a simple and environmentally friendly solution-processed approach, which were subsequently used as a counter electrode (CE) alternative to the noble metal Pt for triiodide reduction in dye-sensitized solar cells (DSSCs). The resultant SnS2 -based CE with a thickness of about 300?nm exhibited excellent electrochemical catalytic activity for catalyzing the reduction of triiodide and demonstrated comparable power conversion efficiency of 7.64?% with that of expensive Pt-based CE in DSSCs (7.71?%). When functionalized with a small amount of carbon nanoparticles, the SnS2 NS-based CE showed even better performance of 8.06?% than Pt under the same conditions. Considering the facile fabrication method, optical transparency, low cost, and remarkable catalytic property, this study on SnS2 NSs may shed light on the large-scale production of electrocatalytic electrode materials for low-cost photovoltaic devices. PMID:24924927

Bai, Yang; Zong, Xu; Yu, Hua; Chen, Zhi-Gang; Wang, Lianzhou

2014-07-01

108

Fabrication and photoelectrochemical properties of interdigitated array microelectrodes consisting of optically transparent and nontransparent band electrodes  

SciTech Connect

Photogalvanic cells based on the photoinduced redox reactions of two redox couples can convert solar energy. However, their conversion efficiency is poor because of the recombination of photochemically produced active species before they reach the electrodes and the two-way electrode processes of those species. In an attempt to improve the conversion efficiency, the use of closely spaced electrodes structures has been proposed, such as a thin-layer photocell with a transparent electrode. A lithologic fabrication method for a new interdigitated array microelectrode (IDA) consisting of optically transparent (ITO) and nontransparent (Pt) arrays of band electrodes on a quartz substrate is presented. The new IDA is applied to the Ru(bpy){sub 3}{sup 2+}-Fe{sup 3+} photogalvanic system. The effective separation of photoinduced active species between very closely spaced electrodes is achieved by utilizing the shadow of the nontransparent electrode generated by illumination from the rear of the IDA. This back-illumination method using the new IDA is effective in increasing the conversion efficiency.

Horiuchi, Tsutomu; Niwa, Osamu; Morita, Masao [Nippon Telegraph and Telephone Corp., Atsugi, Kanagawa (Japan). NTT Basic Research Labs.

1995-09-01

109

Light-trapping design of graphene transparent electrodes for efficient thin-film silicon solar cells.  

PubMed

In this paper, the performance of solar cells with graphene transparent electrodes is compared with cells using conventional indium tin oxide (ITO) electrodes, and it is demonstrated the optical absorption of solar cells with bare graphene structure is worse than that of bare ITO structure because of the higher refractive index of graphene. To enhance the light trapping of graphene-based thin-film solar cells, a simple two-layer SiO(2)/SiC structure is proposed as antireflection coatings deposited on top of graphene transparent electrodes, and the thickness of each layer is optimized by differential evolution in order to enhance the optical absorption of a-Si:H thin-film solar cells to the greatest degree. The optimization results demonstrate the optimal SiO(2)/SiC/graphene structure can obtain 37.30% enhancement with respect to bare ITO structure, which has obviously exceeded the light-trapping enhancement of 34.15% for the optimal SiO(2)/SiC/ITO structure. Therefore, with the aid of the light-trapping structure, the graphene films are a very promising indium-free transparent electrode substitute for the conventional ITO electrode for use in cost-efficient thin-film silicon solar cells. PMID:22945173

Zhao, Yongxiang; Chen, Fei; Shen, Qiang; Zhang, Lianmeng

2012-09-01

110

Transparent Electrode Materials for Simultaneous Amperometric Detection of Exocytosis and Fluorescence Microscopy  

PubMed Central

We have developed and tested transparent microelectrode arrays capable of simultaneous amperometric measurement of oxidizable molecules and fluorescence imaging through the electrodes. Surface patterned microelectrodes were fabricated from three different conducting materials: Indium-tin-oxide (ITO), nitrogen-doped diamond-like carbon (DLC) deposited on top of ITO, or very thin (12–17 nm) gold films on glass substrates. Chromaffin cells loaded with lysotracker green or acridine orange dye were placed atop the electrodes and vesicle fluorescence imaged with total internal reflection fluorescence (TIRF) microscopy while catecholamine release from single vesicles was measured as amperometric spikes with the surface patterned electrodes. Electrodes fabricated from all three materials were capable of detecting amperometric signals with high resolution. Unexpectedly, amperometric spikes recorded with ITO electrodes had only about half the amplitude and about half as much charge as those detected with DLC or gold electrodes, indicating that the ITO electrodes are not as sensitive as gold or DLC electrodes for measurement of quantal catecholamine release. The lower sensitivity of ITO electrodes was confirmed by chronoamperometry measurements comparing the currents in the presence of different analytes with the different electrode materials.

Kisler, Kassandra; Kim, Brian N.; Liu, Xin; Berberian, Khajak; Fang, Qinghua; Mathai, Cherian J.; Gangopadhyay, Shubhra; Gillis, Kevin D.; Lindau, Manfred

2012-01-01

111

High figure-of-merit ultrathin metal transparent electrodes incorporating a conductive grid  

SciTech Connect

It is known that ultrathin (<10 nm) metal films (UTMFs) can achieve high level of optical transparency at the expense of the electrical sheet resistance. In this letter, we propose a design, the incorporation of an ad hoc conductive grid, which can significantly reduce the sheet resistance of UTMF based transparent electrodes, leaving practically unchanged their transparency. The calculated highest figure-of-merit corresponds to a filling factor and a grid spacing-to-linewidth ratio of 0.025 and 39, respectively. To demonstrate the capability of the proposed method the sheet resistance of a continuous 2 nm Ni film (>950 OMEGA/square) is reduced to approx6.5 OMEGA/square when a 100 nm thick Cu grid is deposited on it. The transparency is instead maintained at values exceeding 75%. These results, which can be further improved by making thicker grids, already demonstrate the potential in applications, such as photovoltaic cells, optical detectors and displays.

Ghosh, D. S.; Chen, T. L. [ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Castelldefels, Barcelona, 08860 Catalunya (Spain); Pruneri, V. [ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Castelldefels, Barcelona, 08860 Catalunya (Spain); ICREA-Institucio Catalana de Recerca i Estudis Avancats, 08010 Barcelona (Spain)

2010-01-25

112

Ultra high-sensitivity fission counter with transmission line electrode configuration  

SciTech Connect

An ultrahigh-sensitivity fission counter (UHSFC) prototype was designed, fabricated, and tested. The objective of this research was development of a fission counter system for ex-vessel, source-range flux monitoring having a neutron sensitivity of greater than or equal to 40 counts s/sup -1/ (neutrons/(cm/sup 2/xs))/sup -1/ (greater than or equal to 40 cps/nv) and a size comparable to that of a BF/sub 3/ proportional counter system. Also, the UHSFC system was required to be operable under conditions beyond the capabilities of BF/sup 3/ counters: up to a temperature of 450 K and in a gamma radiation field of 7.2 x 10/sup -4/ C(kg.s)/sup -1/ (i.e., 10/sup 4/ R/h). The sensitivity requirement (40 cps/nv) was met by assembling two transmission line fission counters (TLFCs) within a common envelope. The size requirement (less than or equal to 14 cm diameter, less than or equal to 80 cm length) was met by using electrodes arranged to maximize the ratio of electrode area to sensitive volume. The measured neutron sensitivity for each TLFC is 23.5 cps/nv at 4.5 x 10/sup 4/ R/h and 450 K. The UHSFC is filled with a recently developed gas (80% Ar, 20% CF/sub 4/ at 263 kPa pressure) of high electron drift velocity. The electrode area (5 m/sup 2/) is coated with 88 g of enriched uranium (93.15% /sup 235/U, 0.99% /sup 234/U, balance /sup 238/U). The impedance of the lumped element LC transmission lines is 25 ..cap omega.., the bandwidth 100 MHz, and the delay 4 ns per node (each TLFC has 58 nodes). Pulse-height and time discrimination is used to mitigate the effects of noise from the alpha pileup current of the uranium coating.

Valentine, K.H.; Allin, G.W.; Clay, W.T.; Fowler, C.E.; Guerrant, G.C.; Harter, J.A.; Kopp, M.K.

1983-02-01

113

Photoactive films of photosystem I on transparent reduced graphene oxide electrodes.  

PubMed

Photosystem I (PSI) is a photoactive electron-transport protein found in plants that participates in the process of photosynthesis. Because of PSI's abundance in nature and its efficiency with charge transfer and separation, there is a great interest in applying the protein in photoactive electrodes. Here, we developed a completely organic, transparent, conductive electrode using reduced graphene oxide (RGO) on which a multilayer of PSI could be deposited. The resulting photoactive electrode demonstrated current densities comparable to that of a gold electrode modified with a multilayer film of PSI and significantly higher than that of a graphene electrode modified with a monolayer film of PSI. The relatively large photocurrents produced by integrating PSI with RGO and using an opaque, organic mediator can be applied to the facile production of more economic solar energy conversion devices. PMID:25029217

Darby, Emily; LeBlanc, Gabriel; Gizzie, Evan A; Winter, Kevin M; Jennings, G Kane; Cliffel, David E

2014-07-29

114

High electrochromic performance of co-sputtered vanadium–titanium oxide as a counter electrode  

Microsoft Academic Search

This study examined the material and electrochromic properties of vanadium–titanium oxides (V–Ti oxides) as a counter electrode material in electrochromic devices. These oxides were deposited on an ITO substrate using a co-sputtering method at different levels of RF power. Electrochemical experiments of these oxides were carried out using half-cell and semi full-cell tests which are good methods for measuring the

Ju Wan Lim; Sung Jong Yoo; Sun Ha Park; Seong Uk Yun; Yung-Eun Sung

2009-01-01

115

Dye-sensitized solar cells using graphene-based carbon nano composite as counter electrode  

Microsoft Academic Search

We demonstrated a counter electrode in dye-sensitized solar cells (DSSCs) using the graphene-based multi-walled carbon nanotubes (GMWNTs) structure. Graphene layers were prepared by drop casting on a SiO2\\/Si substrate and multi-walled carbon nanotubes (MWNTs) were synthesized on graphene layers using iron catalyst by chemical vapor deposition. The structural properties of GMWNTs were investigated by transmission electron microscope and field-emission scanning

Hyonkwang Choi; Hyunkook Kim; Sookhyun Hwang; Wonbong Choi; Minhyon Jeon

2011-01-01

116

Economical and effective sulfide catalysts for dye-sensitized solar cells as counter electrodes.  

PubMed

Molybdenum sulfide (MoS(2)) and tungsten sulfide (WS(2)) are proposed as counter electrode (CE) catalysts in a I(3)(-)/I(-) and T(2)/T(-) based dye-sensitized solar cells (DSCs) system. The I(3)(-)/I(-) based DSCs using MoS(2) and WS(2) CEs achieved power conversion efficiencies of 7.59% and 7.73%, respectively. PMID:21984309

Wu, Mingxing; Wang, Yudi; Lin, Xiao; Yu, Naisen; Wang, Liang; Wang, Linlin; Hagfeldt, Anders; Ma, Tingli

2011-11-21

117

Sol-Gel Synthesis of Vanadate-Based Thin Films as Counter Electrodes in Electrochromic Devices  

Microsoft Academic Search

V2O5-based thin films were prepared via the sol-gel method in order to obtain semiconductive films suitable as counter electrodes in electrochemical devices (e.g. electrochromic windows). Different metal precursors (nickel 2,4-pentanedionate, NiCl2, BiCl3, SbCl3) were added, after dissolution, into the starting vanadium oxo-triisopropoxide solution in the presence of acetic acid as a chelating agent. Preventing different synthesis conditions due to the

Riccardo Ceccato; Giovanni Carturan; Franco Decker; Florinda Artuso

2003-01-01

118

Micro coulter counters with platinum black electroplated electrodes for human blood cell sensing.  

PubMed

We demonstrated a novel micro Coulter counter featuring platinum-black electrodes for human blood cell counting application. Two designs of micro Coulter counter were fabricated using two distinct technologies: integrated parylene and soft lithography. Platinum-black enhanced detection in the intermediate frequency range ( approximately 100 Hz to 7 MHz), which is the operation frequency suitable for sensing the cells flowing by the electrodes. A detailed theoretical modeling of the sensing mechanism has been performed for the design of the electrodes, and electrical impedance spectra measurements confirmed the theoretical model. The surface morphology and roughness of the platinum black electroplated surface were characterized by SEM and AFM measurements. Polystyrene beads of various sizes were initially used to validate the operation of the devices, and using excitation frequency of 10 kHz, the signal magnitude was found to be correlated with the volume of the individual bead. Human blood cell sensing was successfully demonstrated with diluted whole blood and leukocyte rich plasma under the same excitation frequency. The histogram of impedance magnitude of the cells matched well with volume distributions of erythrocytes and leukocytes measured by conventional counting techniques. Micro Coulter counters have the advantages of small foot-print, low sample volume, and reduced cost of operation. Further development of the devices can lead to the development of a highly-sensitive and high-throughput handheld blood counting system for point-of-care applications. PMID:17876707

Zheng, Siyang; Liu, Mike; Tai, Yu-Chong

2008-04-01

119

Compound Ag nanocluster-graphene electrodes as transparent and current spreading electrodes for improved light output power in near-ultraviolet light emitting diodes  

NASA Astrophysics Data System (ADS)

We introduced a two-dimensional graphene network on a Ag nanocluster as a transparent and current spreading electrode (TCSE) for a near-ultraviolet light emitting diode (NUV-LED), and compared the performance with those with graphene electrodes or conventional indium tin oxide (ITO) electrodes. The current–voltage characteristics and electroluminescence (EL) data showed that compound Ag nanocluster-graphene (CA-G) electrodes operated well as TCSEs in NUV-LED devices. The forward voltage at an input current of 20 mA was 4.06 V for the NUV-LED of current spreading electrodes with CA-G electrodes, which is only slightly higher than the value 3.96 V with ITO electrodes as TCSEs. The EL intensity of NUV-LEDs with CA-G electrodes also showed a slight increase, compared to that of NUV-LEDs with planar ITO transparent conducting electrodes.

Seo, Tae Hoon; Kim, Seongjun; Jong Kim, Myung; Kim, Hyunsoo; Suh, Eun-Kyung

2014-05-01

120

DSSC with a novel Pt counter electrodes using pulsed electroplating techniques  

Microsoft Academic Search

The thin Pt electrode on transparent conductive oxide (TCO) substrate, i.e., FTO\\/glass, for the dye-sensitized solar cell was prepared by a pulsed electrodeposition method. The characteristic properties of the pulse-plated Pt film were prepared and compared with the conventional sputtered Pt film. The composition and surface morphology of the Pt thin film were examined by scanning electron microscope with energy

Chun-Chen Yang; Huan Qing Zhang; Yu Rong Zheng

2011-01-01

121

Highly stretchable and transparent nanomesh electrodes made by grain boundary lithography  

NASA Astrophysics Data System (ADS)

Foldable photoelectronics and muscle-like transducers require highly stretchable and transparent electrical conductors. Some conducting oxides are transparent, but not stretchable. Carbon nanotube films, graphene sheets and metal-nanowire meshes can be both stretchable and transparent, but their electrical resistances increase steeply with strain <100%. Here we present highly stretchable and transparent Au nanomesh electrodes on elastomers made by grain boundary lithography. The change in sheet resistance of Au nanomeshes is modest with a one-time strain of ~160% (from ~21?? per square to ~67?? per square), or after 1,000 cycles at a strain of 50%. The good stretchability lies in two aspects: the stretched nanomesh undergoes instability and deflects out-of-plane, while the substrate stabilizes the rupture of Au wires, forming distributed slits. Larger ratio of mesh-size to wire-width also leads to better stretchability. The highly stretchable and transparent Au nanomesh electrodes are promising for applications in foldable photoelectronics and muscle-like transducers.

Guo, Chuan Fei; Sun, Tianyi; Liu, Qihan; Suo, Zhigang; Ren, Zhifeng

2014-01-01

122

Highly stretchable and transparent nanomesh electrodes made by grain boundary lithography.  

PubMed

Foldable photoelectronics and muscle-like transducers require highly stretchable and transparent electrical conductors. Some conducting oxides are transparent, but not stretchable. Carbon nanotube films, graphene sheets and metal-nanowire meshes can be both stretchable and transparent, but their electrical resistances increase steeply with strain <100%. Here we present highly stretchable and transparent Au nanomesh electrodes on elastomers made by grain boundary lithography. The change in sheet resistance of Au nanomeshes is modest with a one-time strain of ~160% (from ~21 ? per square to ~67 ? per square), or after 1,000 cycles at a strain of 50%. The good stretchability lies in two aspects: the stretched nanomesh undergoes instability and deflects out-of-plane, while the substrate stabilizes the rupture of Au wires, forming distributed slits. Larger ratio of mesh-size to wire-width also leads to better stretchability. The highly stretchable and transparent Au nanomesh electrodes are promising for applications in foldable photoelectronics and muscle-like transducers. PMID:24469072

Guo, Chuan Fei; Sun, Tianyi; Liu, Qihan; Suo, Zhigang; Ren, Zhifeng

2014-01-01

123

Nanostructured titanium nitride/PEDOT:PSS composite films as counter electrodes of dye-sensitized solar cells.  

PubMed

The composite films of titanium nitride in conjunction with polystyrenesulfonate-doped poly (3,4-ethylene-dioxythiophene) (PEDOT:PSS) were prepared by a simple mechanical mixture of TiN and PEDOT:PSS under ultrasonication, which was demonstrated to deliver an effectively combined network of both high electrical conductivity and superior electrocatalytic activity. The composite films have been explored as an alternative for the counter electrodes of dye-sensitized solar cells. It was manifested that these nanostructured TiN-PEDOT:PSS composite films displayed excellent performance comparable to Pt-FTO counter electrode due to the combined network endowing more favorable and efficient interfacial active sites. Among them, the energy conversion efficiency of the cell with TiN(P)-PEDOT:PSS as counter electrode reached 7.06%, which was superior to 6.57% of the cell with Pt-FTO counter electrode under the same experimental conditions. PMID:22264094

Xu, Hongxia; Zhang, Xiaoying; Zhang, Chuanjian; Liu, Zhihong; Zhou, Xinhong; Pang, Shuping; Chen, Xiao; Dong, Shanmu; Zhang, Zhongyi; Zhang, Lixue; Han, Pengxian; Wang, Xiaogang; Cui, Guanglei

2012-02-01

124

Time-domain modeling of silver nanowires-graphene transparent conducting electrodes  

NASA Astrophysics Data System (ADS)

Transparent conducting electrodes (TCE) consisting of silver nanowires (SNW) with a single-layer graphene (SLG) cover demonstrate higher optical transparency and lower sheet resistance than indium tin oxide (ITO) and are comparable to the best reported results in TCEs. SNW layer is simulated using the spectral averaging of the FDTD transmittance data from indiscriminately selected frames. Simulations are done for a number of frames until a convergent set of averaged spectra is obtained. SLG layer is simulated separately and contributes to the total transmittance as a multiplicative constant.

Fang, Jieran; Das, Suprem R.; Prokopeva, Ludmila J.; Shalaev, Vladimir M.; Janes, David B.; Kildishev, Alexander V.

2013-09-01

125

Patterned Single-Wall Carbon Nanotube Transparent Conducting Films for Liquid Crystal Switching Electrodes  

NASA Astrophysics Data System (ADS)

We have fabricated transparent and electrically conductive single-wall carbon nanotube (SWCNT) thin films for liquid crystal switching electrodes. The SWCNT film had a sheet resistance of 91.02 ?/\\square and a transmittance of 92.33% at 550 nm. Our CNT-based transparent conducting film (TCF) patterning technique is a combination of photolithography and O2 plasma etching. We were able to pattern CNT-TCFs with a high resolution, and as small as 4 ?m, and to fabricate them with various shapes and patterns. Our CNT-TCFs were used to successfully switch liquid crystal cells with 100 ?m and 15 mm line widths.

Lee, Eun Hye; Ryu, Je Hwang; Jang, Jin; Park, Kyu Chang

2011-03-01

126

Synthesis of MWNTs using thermal chemical vapor deposition for the application of a counter electrode for DSSCs  

Microsoft Academic Search

MWNTs (Multi-wall Carbon nanotubes) were grown using thermal CVD at a low temperature of 530 °C to be fabricated as a counter electrode of dye-sensitized solar cells (DSSCs). Ammonia gas and acetylene gas were introduced as reactive gas sources with 90 sccm and 108 sccm, respectively. DSSCs using CNT and Pt counter electrodes were fabricated using conventional method to compare its efficiencies. As

Ji Young Roh; Yang Hee Kim; Caroline Sunyong Lee

2011-01-01

127

Totally Organic Polymer-Based Electrochromic Cell Using TEMPO-Substituted Polynorbornene as a Counter Electrode-Active Material  

Microsoft Academic Search

An electrochromic (EC) cell using a viologen-based polymer as an EC material and a radical polymer bearing a redox-active 2,2,6,6-tetramethylpiperidin-N-oxyl (TEMPO) group per repeating unit as a counter electroactive material was fabricated. The radical polymer was spin-coated on an ITO\\/glass electrode as the counter electrode of the EC cell. The electrochromic material of the cell was a polyion complex consisted

Yusuke Takahashi; Naoki Hayashi; Kenichi Oyaizu; Kenji Honda; Hiroyuki Nishide

2008-01-01

128

Performance characteristics of dye-sensitized solar cells with counter electrode based on NiP-plated glass and titanium plate  

Microsoft Academic Search

The counter electrodes based on NiP-plated glass and titanium plate were prepared. The performance characteristics of the dye-sensitized solar cells with platinized NiP-plated glass electrode (Pt\\/NiP electrode) and platinized titanium plate electrode (Pt\\/TP electrode) were discussed. Pt\\/NiP electrode and Pt\\/TP electrode showed the same catalytic activity for triiodide reduction compared with platinized fluorine-doped tin oxide conducting glass electrode (Pt\\/FTO electrode).

Guiqiang Wang; Yuan Lin

2009-01-01

129

Nanoparticles for Applications as Counter Electrodes of CdS Quantum Dot-Sensitized Solar Cells  

NASA Astrophysics Data System (ADS)

Cu2ZnSnS4 (CZTS) nanoparticles have been synthesized through a one-step solvothermal route, which exhibited a nearly single kesterite structure with a fundamental band gap of ˜1.54 eV. Quantum dots-sensitized solar cells were fabricated based on CZTS counter electrodes and CdS QD-sensitized TiO2 NRs photoelectrodes with various thicknesses of QD sensitization layers. The cells based on a CZTS electrode, compared with other single-layer DSSCs in this study, had the highest conversion efficiency of 0.27% (for CdS layer numbers of 9), which was obviously higher than Pt. The performance improvement was attributed to the better stability, sunlight sensitivity, and the resulting photoelectrocatalytic activity of the CZTS electrodes.

Gu, Xiuquan; Zhang, Shuang; Qiang, Yinghuai; Zhao, Yulong; Zhu, Lei

2014-07-01

130

Nanostructured networks of single wall carbon nanotubes for highly transparent, conductive, and anti-reflective flexible electrodes  

NASA Astrophysics Data System (ADS)

Highly transparent, anti-reflective, flexible, and conductive electrodes are produced by nanopatterning of a polymer composite made of single wall carbon nanotubes (SWNTs). The formation of nanostructures creates interconnected nanotubes and vertically aligned SWNT networks which greatly improves charge transport compared to a traditionally mixed composite. These electrodes moreover possess high transparency (98% at 550 nm) and good anti-reflective properties. The use of low nanotube loadings provides an economical solution to make conductive and highly transparent flexible electrodes. The process used is simple and can be easily scaled to large areas by roll to roll processes.

Boulanger, Nicolas; Barbero, David R.

2013-07-01

131

Broadband light absorption enhancement in polymer photovoltaics using metal nanowall gratings as transparent electrodes.  

PubMed

The authors investigate light absorption in organic solar cells in which indium tin oxide (ITO) is replaced by a new metallic architecture (grating) as a transparent electrode. Different from typical metal nanowire gratings, our gratings consist of metal nanowalls with nanoscale footprint and (sub)microscale height [Adv. Mater. 23, 2469 (2011)], thus ensuring high optical transmittance and electrical conductivity. Simulations reveal that a broadband and polarization-insensitive light absorption enhancement is achieved via two mechanisms, when such silver nanowall gratings are employed in P3HT:PCBM based solar cells. Overall absorption enhanced by ~23% compared to a reference cell with ITO electrode. PMID:22714211

Ye, Zhuo; Chaudhary, Sumit; Kuang, Ping; Ho, Kai-Ming

2012-05-21

132

Broadband light absorption enhancement in polymer photovoltaics using metal nanowall gratings as transparent electrodes  

SciTech Connect

The authors investigate light absorption in organic solar cells in which indium tin oxide (ITO) is replaced by a new metallic architecture (grating) as a transparent electrode. Different from typical metal nanowire gratings, our gratings consist of metal nanowalls with nanoscale footprint and (sub)microscale height [Adv. Mater. 23, 2469 (2011)], thus ensuring high optical transmittance and electrical conductivity. Simulations reveal that a broadband and polarization-insensitive light absorption enhancement is achieved via two mechanisms, when such silver nanowall gratings are employed in P3HT:PCBM based solar cells. Overall absorption enhanced by ~23% compared to a reference cell with ITO electrode.

Ye, Zhuo; Chaudhary, Sumit; Kuang, Ping; Ho, Kai-Ming

2012-05-15

133

Principles of perfect and ultrathin anti-reflection with applications to transparent electrode  

NASA Astrophysics Data System (ADS)

Anti-reflection(AR), a well-known technique of reducing unwanted reflections by applying an impedance matching layer, works for a specific wavelength and require the coating layer to be a quarter wavelength thick. A broadband operation of AR, however, is not fully understood except for the trial and error method. Here, we present a systematic analytic method of AR without the restriction of wavelength or thickness, i.e. achieving a perfect AR. Specifically, we find analytic permittivity and permeability profiles that remove any given impedance mismatch at the interface between two different dielectrics in a frequency independent way. Ultra-thin AR coating is also shown to be possible and confirmed experimentally with the l/25-wavelength thick AR coating layer made of metamaterials. We apply the concept of ultrathin double layer AR to the transparent conducting electrode, which we demonstrate by fabricating a low reflective dielectric/metal-layered electrode that provides significant electrical conductivity and light transparency.

Kim, Kyoung-Ho; Park, Q.-Han

2014-03-01

134

Transfer of large-area graphene films for high-performance transparent conductive electrodes.  

PubMed

Graphene, a two-dimensional monolayer of sp(2)-bonded carbon atoms, has been attracting great interest due to its unique transport properties. One of the promising applications of graphene is as a transparent conductive electrode owing to its high optical transmittance and conductivity. In this paper, we report on an improved transfer process of large-area graphene grown on Cu foils by chemical vapor deposition. The transferred graphene films have high electrical conductivity and high optical transmittance that make them suitable for transparent conductive electrode applications. The improved transfer processes will also be of great value for the fabrication of electronic devices such as field effect transistor and bilayer pseudospin field effect transistor devices. PMID:19845330

Li, Xuesong; Zhu, Yanwu; Cai, Weiwei; Borysiak, Mark; Han, Boyang; Chen, David; Piner, Richard D; Colombo, Luigi; Ruoff, Rodney S

2009-12-01

135

Ag nanowire percolating network embedded in indium tin oxide nanoparticles for printable transparent conducting electrodes  

NASA Astrophysics Data System (ADS)

Solution-based printable transparent conducting electrodes consisting of Ag nanowire (NW) and indium tin oxide (ITO) nanoparticles (NPs) were fabricated by simple brush painting at room temperature under atmospheric ambient conditions. Effectively embedding the Ag NW percolating network into the ITO NPs provided a conduction path, led to a metallic conduction behavior of the ITO NPs/Ag NW/ITO NPs multilayer and supplied electrons into the ITO NPs. The optimized ITO NPs/Ag NW/ITO NPs multilayer showed a sheet resistance of 16.57 ?/sq and an optical transparency of 79.50% without post annealing. Based on high resolution transmission electron microscope analysis, we investigated the microstructure and interface structure of the ITO NPs/Ag NW/ITO NPs multilayer electrodes and suggested a possible mechanism to explain the low resistivity of the multilayers.

Jeong, Jin-A.; Kim, Han-Ki

2014-02-01

136

Transparent Electrode Patterning using Laser Ablation for In-Plane Switching Liquid Crystal Display  

NASA Astrophysics Data System (ADS)

Transparent indium tin oxides (ITO) electrodes were patterned using flash lamp pumped Q-switched Nd: YAG laser ablation technique. The Optical microscopy, atomic force microscopy and energy dispersive x-ray spectrum along with scanning electron microscope analysis shows the depth and width of the ablated area and the elements available in the ablated area. In-plane switching liquid crystal display were constructed using the patterned indium tin oxide and its switching characteristics are investigated.

Chenchiliyan, Manoop; Palengara, Sudheesh; Varghese, Soney

2011-10-01

137

Influence of multi-walled carbon nanotubes on electrochemical performance of transparent graphene electrodes  

Microsoft Academic Search

In this work, carbon–carbon nanocomposites as transparent electrodes were prepared by a chemical reduction of graphite oxide (GO) and multi-walled carbon nanotubes (MWNTs). The electric, optical, and electrochemical properties of graphene-MWNT nanocomposites (G-MCs) were investigated as a function of the MWNT content. It was found that chemically bonded G-MCs were successfully formed with a reduction of the functional groups of

Ki-Seok Kim; Kyong-Yop Rhee; Soo-Jin Park

2011-01-01

138

Efficient bulk-heterojunction photovoltaic cells with transparent multi-layer graphene electrodes  

Microsoft Academic Search

We present the results of applying multi-layer graphene (MLG) films as transparent conductive electrodes in organic photovoltaic devices (OPVs). The MLG films synthesized at different growth temperatures by chemical vapor deposition were applied to OPVs. The performance of OPVs with 1000°C-grown MLG films was found to be the best with a power conversion efficiency (PCE) of ?1.3%. The PCE was

Minhyeok Choe; Byoung Hoon Lee; Gunho Jo; June Park; Woojin Park; Sangchul Lee; Woong-Ki Hong; Maeng-Je Seong; Yung Ho Kahng; Kwanghee Lee; Takhee Lee

2010-01-01

139

Outstanding flexibility of organic memory devices with transparent graphene top electrodes  

Microsoft Academic Search

The organic memory device was fabricated 8 × 8 cross-bar array-type with transparent graphene electrodes on a poly(ethylene terephthalate) (PET) substrate. The active layer of the memory devices is a composite of polyimide and 6-phenyl-C61 butyric acid methyl ester (PCBM). The sheet resistance of the graphene film on memory device was found to be ?270?\\/?, and the transmittance of separated

Yongsung Ji; Sangchul Lee; Byungjin Cho; Sunghoon Song; Takhee Lee

2011-01-01

140

Reduced graphene oxide/copper nanowire hybrid films as high-performance transparent electrodes.  

PubMed

Hybrid films composed of reduced graphene oxide (RG-O) and Cu nanowires (NWs) were prepared. Compared to Cu NW films, the RG-O/Cu NW hybrid films have improved electrical conductivity, oxidation resistance, substrate adhesion, and stability in harsh environments. The RG-O/Cu NW films were used as transparent electrodes in Prussian blue (PB)-based electrochromic devices where they performed significantly better than pure Cu NW films. PMID:23383736

Kholmanov, Iskandar N; Domingues, Sergio H; Chou, Harry; Wang, Xiaohan; Tan, Cheng; Kim, Jin-Young; Li, Huifeng; Piner, Richard; Zarbin, Aldo J G; Ruoff, Rodney S

2013-02-26

141

Three-dimensional graphene foam-based transparent conductive electrodes in GaN-based blue light-emitting diodes  

NASA Astrophysics Data System (ADS)

We demonstrated three-dimensional (3D) graphene foam-based transparent conductive electrodes in GaN-based blue light-emitting diodes (LEDs). A 3D graphene foam structure grown on 3D Cu foam using a chemical vapor deposition method was transferred onto a p-GaN layer of blue LEDs. Optical and electrical performances were greatly enhanced by employing 3D graphene foam as transparent conductive electrodes in blue LED devices, which were analyzed by electroluminescence measurements, micro-Raman spectroscopy, and light intensity-current-voltage testing. The forward operating voltage and the light output power at an injection current of 100 mA of the GaN-based blue LEDs with a graphene foam-based transparent conductive electrode were improved by ~26% and ~14%, respectively. The robustness, high transmittance, and outstanding conductivity of 3D graphene foam show great potentials for advanced transparent conductive electrodes in optoelectronic devices.

Kim, Byung-Jae; Yang, Gwangseok; Joo Park, Min; Seop Kwak, Joon; Hyeon Baik, Kwang; Kim, Donghwan; Kim, Jihyun

2013-04-01

142

Optimization of transparent and reflecting electrodes for amorphous silicon solar cells. Annual subcontract report, April 1, 1994--March 31, 1995.  

National Technical Information Service (NTIS)

Transparent and reflecting electrodes are important parts of the structure of amorphous silicon solar cells. We report improved methods for depositing zinc oxide, deposition of tin nitride as a potential reflection-enhancing diffusion barrier between the ...

R. G. Gordon

1995-01-01

143

Bragg stack-functionalized counter electrode for solid-state dye-sensitized solar cells.  

PubMed

A highly reflective counter electrode is prepared through the deposition of alternating layers of organized mesoporous TiO(2) (om-TiO(2)) and colloidal SiO(2) (col-SiO(2)) nanoparticles. We present the effects of introducing this counter electrode into dye-sensitized solar cells (DSSCs) for maximizing light harvesting properties. The om-TiO(2) layers with a high refractive index are prepared by using an atomic transfer radical polymerization and a sol-gel process, in which a polyvinyl chloride-g-poly(oxyethylene) methacrylate graft copolymer is used as a structure-directing agent. The col-SiO(2) layers with a low refractive index are prepared by spin-coating commercially available silica nanoparticles. The properties of the Bragg stack (BS)-functionalized counter electrode in DSSCs are analyzed by using a variety of techniques, including spectroscopic ellipsometry, SEM, UV/Vis spectroscopy, incident photon-to-electron conversion efficiency, electrochemical impedance spectroscopy, and intensity modulated photocurrent/voltage spectroscopy measurements, to understand the critical factors contributing to the cell performance. When incorporated into DSSCs that are used in conjunction with a polymerized ionic liquid as the solid electrolyte, the energy conversion efficiency of this solid-state DSSC (ssDSSC) approaches 6.6 %, which is one of the highest of the reported N719 dye-based ssDSSCs. Detailed optical and electrochemical analyses of the device performance show that this assembly yields enhanced light harvesting without the negative effects of charge recombination or electrolyte penetration, which thus, presents new possibilities for effective light management. PMID:23576320

Park, Jung Tae; Prosser, Jacob H; Kim, Dong Jun; Kim, Jong Hak; Lee, Daeyeon

2013-05-01

144

Interaction of niobium counter electrodes with aluminum oxide and rare-earth oxide tunnel barriers  

NASA Astrophysics Data System (ADS)

With the use of rare-earth oxide and aluminum oxide barriers, low-leakage-current tunnel junctions can be made if the oxidation takes place in the presence of some humidity, and if the counter electrode is not niobium. It is proposed that when these oxides form in the presence of H2O, the pores of the oxides become sealed by surface O-H groups, by which process the oxide film becomes a good insulator and remains as such if the counter electrode is nonreactive. When niobium, which is a very reactive metal, is deposited as a counter electrode, the first arriving Nb atoms form NbO (metallic) with the O-H groups in the pores, thereby opening up the pores and leading to tunnel barriers with shorts. The proposed mechanism is supported by heats-of-decomposition arguments, previously reported inelastic electron tunneling spectra of Al-Al oxide-Pb, Ho-Ho oxide-Pb, and Er-Er oxide-Pb junctions as well as new in situ x-ray photoelectron spectroscopy studies made on evaporated yttrium films. When freshly deposited yttrium films were oxidized in 5×10-7-Torr(UHV) pure oxygen, Y2O3 formed and the spectrum showed only a single O 1s peak. Upon deposition of 5-Å Nb, no interaction was detected between the yttrium oxide and niobium. If, however, the freshly deposited yttrium films were oxidized in air or water vapor, the O 1s signal showed a second, higher-energy peak representative of O-H groups. After the depositing of niobium on this yttrium oxide hydroxide, the first-arriving Nb atoms formed a NbO compound while the second O 1s peak representative of O-H groups disappeared from the spectrum.

Ronay, Maria; Latta, E.-E.

1983-02-01

145

Direct tri-constituent co-assembly of highly ordered mesoporous carbon counter electrode for dye-sensitized solar cells.  

PubMed

Controlling over ordered porosity by self-assembly is challenging in the area of materials science. Materials with highly ordered aperture are favorable candidates in catalysis and energy conversion device. Here we describe a facile process to synthesize highly ordered mesoporous carbon (OMC) by direct tri-constituent co-assembly method, which uses resols as the carbon precursor, tri-block copolymer F127 as the soft template and tetraethoxysilane (TEOS) as the inorganic precursor. The obtained products are characterized by small-angle X-ray diffraction (SAXD), Brunauer-Emmett-Teller (BET) nitrogen sorption-desorption measurement and transmission electron microscope (TEM). The results indicate that the OMC possesses high surface areas of 1209 m(2) g(-1), homogeneous pore size of 4.6 nm and a large pore volume of 1.65 cm(3) g(-1). The advantages of high electrochemical active surface area and favorable accessible porosity of OMC benefit the catalysis of I(3)(-) to I(-). As a result, the OMC counter electrode displays a remarkable property when it was applied in dye-sensitized solar cells (DSSCs). For comparison, carbon black (CB) counter electrode and Pt counter electrode have also been prepared. When these different counter electrodes were applied for dye-sensitized solar cells (DSSCs), the power-conversion efficiency (?) of the DSSCs with CB counter electrode are measured to be 5.10%, whereas the corresponding values is 6.39% for the DSSC with OMC counter electrode, which is comparable to 6.84% of the cell with Pt counter electrode under the same experimental conditions. PMID:23165970

Peng, Tao; Sun, Weiwei; Sun, Xiaohua; Huang, Niu; Liu, Yumin; Bu, Chenghao; Guo, Shishang; Zhao, Xing-Zhong

2013-01-01

146

Direct tri-constituent co-assembly of highly ordered mesoporous carbon counter electrode for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Controlling over ordered porosity by self-assembly is challenging in the area of materials science. Materials with highly ordered aperture are favorable candidates in catalysis and energy conversion device. Here we describe a facile process to synthesize highly ordered mesoporous carbon (OMC) by direct tri-constituent co-assembly method, which uses resols as the carbon precursor, tri-block copolymer F127 as the soft template and tetraethoxysilane (TEOS) as the inorganic precursor. The obtained products are characterized by small-angle X-ray diffraction (SAXD), Brunauer-Emmett-Teller (BET) nitrogen sorption-desorption measurement and transmission electron microscope (TEM). The results indicate that the OMC possesses high surface areas of 1209 m2 g-1, homogeneous pore size of 4.6 nm and a large pore volume of 1.65 cm3 g-1. The advantages of high electrochemical active surface area and favorable accessible porosity of OMC benefit the catalysis of I3- to I-. As a result, the OMC counter electrode displays a remarkable property when it was applied in dye-sensitized solar cells (DSSCs). For comparison, carbon black (CB) counter electrode and Pt counter electrode have also been prepared. When these different counter electrodes were applied for dye-sensitized solar cells (DSSCs), the power-conversion efficiency (?) of the DSSCs with CB counter electrode are measured to be 5.10%, whereas the corresponding values is 6.39% for the DSSC with OMC counter electrode, which is comparable to 6.84% of the cell with Pt counter electrode under the same experimental conditions.

Peng, Tao; Sun, Weiwei; Sun, Xiaohua; Huang, Niu; Liu, Yumin; Bu, Chenghao; Guo, Shishang; Zhao, Xing-Zhong

2012-12-01

147

ZnS\\/Ag\\/ZnS nano-multilayer films for transparent electrodes in flat display application  

Microsoft Academic Search

In this paper, ZnS\\/Ag\\/ZnS nano-multilayers for transparent electrodes in flat display application have been prepared by thermal evaporation in vacuum. The sheet resistance of the films was low as 3?\\/cm2. And they can be applied as good selective filters with the luminous transmittance Tlum about 90% and IR reflectance above 90%. The merit FTC for revaluing transparent electrodes reached 7.3×10?2??1

Xuanjie Liu; Xun Cai; Jifang Mao; Chengyu Jin

2001-01-01

148

Degradation studies of transparent conductive electrodes on electroactive poly(vinylidene fluoride) for uric acid measurements  

NASA Astrophysics Data System (ADS)

Biochemical analysis of physiological fluids using, for example, lab-on-a-chip devices requires accurate mixing of two or more fluids. This mixing can be assisted by acoustic microagitation using a piezoelectric material, such as the ?-phase of poly(vinylidene fluoride) (?-PVDF). If the analysis is performed using optical absorption spectroscopy and ?-PVDF is located in the optical path, the material and its conductive electrodes must be transparent. Moreover, if, to improve the transmission of the ultrasonic waves to the fluids, the piezoelectric transducer is placed inside the fluidic structures, its degradation must be assessed. In this paper, we report on the degradation properties of transparent conductive oxides, namely, indium tin oxide (ITO) and aluminum-doped zinc oxide, when they are used as electrodes for providing acoustic microagitation. The latter promotes mixing of chemicals involved in the measurement of uric acid concentration in physiological fluids. The results are compared with those for aluminum electrodes. We find that ?-PVDF samples with ITO electrodes do not degrade either with or without acoustic microagitation.

Cardoso, Vanessa F.; Martins, Pedro; Botelho, Gabriela; Rebouta, Luis; Lanceros-Méndez, Senentxu; Minas, Graca

2010-08-01

149

The effect of SWCNT with the functional group deposited on the counter electrode on the dye-sensitized solar cell  

Microsoft Academic Search

This study investigated the applicability of single wall carbon nanotubes (SWCNT) with the functional group deposited on the FTO-glass (Fluorine doped tin oxide, SnO2:F) substrate of the counter electrode for a dye-sensitized solar cell (DSSC). A nanocrystalline TiO2 layer was fabricated on the FTO-glass substrate of the working electrode, and then sintered in a high-temperature furnace. The working electrode with

Chuen-Shii Chou; Che-I Huang; Ru-Yuan Yang; Chun-Po Wang

2010-01-01

150

A new architecture as transparent electrodes for solar and IR applications based on photonic structures via soft lithography  

Microsoft Academic Search

Transparent conducting electrodes with the combination of high optical transmission and good electrical conductivity are essential for solar energy harvesting and electric lighting devices. Currently, indium tin oxide (ITO) is used because ITO offers relatively high transparency (>80%) to visible light and low sheet resistance (Rs = 10 ohms\\/square) for electrical conduction. However, ITO is costly due to limited indium

Ping Kuang

2011-01-01

151

Transparent conducting metal electrode for top emission organic light-emitting devices: Ca-Ag double layer  

Microsoft Academic Search

We have fabricated a transparent conducting double-layer metal electrode for top emission organic light-emitting devices which consists of thin layers of Ca and Ag metals of different thicknesses, deposited by the vacuum evaporation technique. The process is clean and does not damage the underlaying organic layers. High optical transparency over 70%, low reflectivity (14%) in the visible region, and low

R. B. Pode; C. J. Lee; D. G. Moon; J. I. Han

2004-01-01

152

Transparent conducting metal electrode for top emission organic light-emitting devices: Ca–Ag double layer  

Microsoft Academic Search

We have fabricated a transparent conducting double-layer metal electrode for top emission organic light-emitting devices which consists of thin layers of Ca and Ag metals of different thicknesses, deposited by the vacuum evaporation technique. The process is clean and does not damage the underlaying organic layers. High optical transparency over 70%, low reflectivity (14%) in the visible region, and low

R. B. Pode; C. J. Lee; D. G. Moon; J. I. Han

2004-01-01

153

Diamond optically transparent electrodes: demonstration of concept with ferri/ferrocyanide and methyl viologen.  

PubMed

A new type of optically transparent electrode is reported on--an electrically conductive diamond thin film. The electrode was free-standing (0.38 mm thick and 8 mm in diameter), mechanically polished to a 7-nm rms roughness over a 10-microm linear distance, boron-doped (0.05% B/C in the reactant gas mixture), and mounted in a thinlayer transmission cell. The electrode has a short-wavelength cutoff of approximately 225 nm, which is the indirect band gap of the material, and transmits light out to at least 1,000 nm. In theory, the electrode has an optical window from 225 nm well out into the far-infrared, except for the boron acceptor band and the intrinsic multiphonon absorptions. The electrode was used to electrooxidize ferrocyanide to ferricyanide, and the absorbance change associated with the formation of the oxidized product (lambdamax = 420 nm) was spectroscopically monitored. The electrode was also used to electroreduce methyl viologen (MV2+) to the cation radical (MV+*) and the neutral (MV0). The depletion of MV2+ (lambdamax = 257 nm) and formation of MV+* (lambdama = 398 and 605 nm) were spectroscopically monitored. PMID:11289435

Zak, J K; Butler, J E; Swain, G M

2001-03-01

154

Bifacial dye-sensitized solar cells: A strategy to enhance overall efficiency based on transparent polyaniline electrode  

PubMed Central

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its clean, low-cost, high efficiency, good durability, and easy fabrication. However, enhancing the efficiency of the DSSC still is an important issue. Here we devise a bifacial DSSC based on a transparent polyaniline (PANI) counter electrode (CE). Owing to the sunlight irradiation simultaneously from the front and the rear sides, more dye molecules are excited and more carriers are generated, which results in the enhancement of short-circuit current density and therefore overall conversion efficiency. The photoelectric properties of PANI can be improved by modifying with 4-aminothiophenol (4-ATP). The bifacial DSSC with 4-ATP/PANI CE achieves a light-to-electric energy conversion efficiency of 8.35%, which is increased by ~24.6% compared to the DSSC irradiated from the front only. This new concept along with promising results provides a new approach for enhancing the photovoltaic performances of solar cells.

Wu, Jihuai; Li, Yan; Tang, Qunwei; Yue, Gentian; Lin, Jianming; Huang, Miaoliang; Meng, Lijian

2014-01-01

155

Highly flexible and transparent multilayer MoS2 transistors with graphene electrodes.  

PubMed

A highly flexible and transparent transistor is developed based on an exfoliated MoS2 channel and CVD-grown graphene source/drain electrodes. Introducing the 2D nanomaterials provides a high mechanical flexibility, optical transmittance (?74%), and current on/off ratio (>10(4)) with an average field effect mobility of ?4.7 cm(2) V(-1) s(-1), all of which cannot be achieved by other transistors consisting of a MoS2 active channel/metal electrodes or graphene channel/graphene electrodes. In particular, a low Schottky barrier (?22 meV) forms at the MoS2 /graphene interface, which is comparable to the MoS2 /metal interface. The high stability in electronic performance of the devices upon bending up to ±2.2 mm in compressive and tensile modes, and the ability to recover electrical properties after degradation upon annealing, reveal the efficacy of using 2D materials for creating highly flexible and transparent devices. PMID:23420782

Yoon, Jongwon; Park, Woojin; Bae, Ga-Yeong; Kim, Yonghun; Jang, Hun Soo; Hyun, Yujun; Lim, Sung Kwan; Kahng, Yung Ho; Hong, Woong-Ki; Lee, Byoung Hun; Ko, Heung Cho

2013-10-11

156

Nanopatterned conductive polymer films as a Pt, TCO-free counter electrode for low-cost dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

A low-cost nanopatterned highly conductive poly(3,4-ethylenedioxythiophene) (PEDOT) thin film was fabricated on a flexible plastic substrate via a chemical polymerization method combined with a nanoimprinting technique and used as a platinum (Pt), TCO-free counter electrode for dye-sensitized solar cells (DSSCs). The catalytic properties of the nanopatterned PEDOT as the counter electrode in DSSCs were studied using cyclic voltammetry, J-V measurements, impedance spectroscopy, and finite-difference time-domain (FDTD) simulations. The nanopatterned PEDOT counter electrodes exhibit better functionality as a counter electrode for tri-iodide reduction when compared to non-patterned PEDOT-based counter electrodes. The Pt and TCO-free DSSCs with a nanopatterned PEDOT-based counter electrode exhibited a power conversion efficiency of 7.1% under one sunlight illumination (100 mW cm-2), which is comparable to that of conventional DSSCs with standard platinum Pt/FTO paired counter electrodes. The ability to modulate catalytic functionality with changes in nanoscale morphology represents a promising route for developing new counter electrodes of Pt and TCO-free DSSCs.A low-cost nanopatterned highly conductive poly(3,4-ethylenedioxythiophene) (PEDOT) thin film was fabricated on a flexible plastic substrate via a chemical polymerization method combined with a nanoimprinting technique and used as a platinum (Pt), TCO-free counter electrode for dye-sensitized solar cells (DSSCs). The catalytic properties of the nanopatterned PEDOT as the counter electrode in DSSCs were studied using cyclic voltammetry, J-V measurements, impedance spectroscopy, and finite-difference time-domain (FDTD) simulations. The nanopatterned PEDOT counter electrodes exhibit better functionality as a counter electrode for tri-iodide reduction when compared to non-patterned PEDOT-based counter electrodes. The Pt and TCO-free DSSCs with a nanopatterned PEDOT-based counter electrode exhibited a power conversion efficiency of 7.1% under one sunlight illumination (100 mW cm-2), which is comparable to that of conventional DSSCs with standard platinum Pt/FTO paired counter electrodes. The ability to modulate catalytic functionality with changes in nanoscale morphology represents a promising route for developing new counter electrodes of Pt and TCO-free DSSCs. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01294h

Kwon, Jeong; Ganapathy, Veerappan; Kim, Young Hun; Song, Kyung-Deok; Park, Hong-Gyu; Jun, Yongseok; Yoo, Pil J.; Park, Jong Hyeok

2013-08-01

157

High catalytic activity and stability of nickel sulfide and cobalt sulfide hierarchical nanospheres on the counter electrodes for dye-sensitized solar cells.  

PubMed

In situ grown nickel sulfide and cobalt sulfide hierarchical nanospheres on F-doped SnO2 (FTO) substrates exhibited comparable catalytic activities to sputtering Pt on the counter electrodes for dye-sensitized solar cells (DSSCs). The fresh cells with the nickel sulfide and cobalt sulfide on the counter electrodes could reach power conversion efficiencies of 6.81% and 6.59% respectively, approaching an efficiency of 6.85% based on the sputtering Pt counter electrode. Both nickel sulfide and cobalt sulfide counter electrodes could maintain the cell's relatively high performance in the long-term stability test in 504 hours. PMID:24681812

Yang, Jie; Bao, Chunxiong; Zhu, Kai; Yu, Tao; Li, Faming; Liu, Jianguo; Li, Zhaosheng; Zou, Zhigang

2014-05-14

158

Highly efficient and bendable organic solar cells using a three-dimensional transparent conducting electrode.  

PubMed

A three-dimensional (3D) transparent conducting electrode, consisting of a quasi-periodic array of discrete indium-tin-oxide (ITO) nanoparticles superimposed on a highly conducting oxide-metal-oxide multilayer using ITO and silver oxide (AgOx) as oxide and metal layers, respectively, is synthesized on a polymer substrate and used as an anode in highly flexible organic solar cells (OSCs). The 3D electrode is fabricated using vacuum sputtering sequences to achieve self-assembly of distinct ITO nanoparticles on a continuous ITO-AgOx-ITO multilayer at room-temperature without applying conventional high-temperature vapour-liquid-solid growth, solution-based nanoparticle coating, or complicated nanopatterning techniques. Since the 3D electrode enhances the hole-extraction rate in OSCs owing to its high surface area and low effective series resistance for hole transport, OSCs based on this 3D electrode exhibit a power conversion efficiency that is 11-22% higher than that achievable in OSCs by means of conventional planar ITO film-type electrodes. A record high efficiency of 6.74% can be achieved in a bendable OSC fabricated on a poly(ethylene terephthalate) substrate. PMID:24835145

Wang, Wei; Bae, Tae-Sung; Park, Yeon Hyun; Kim, Dong Ho; Lee, Sunghun; Min, Guanghui; Lee, Gun-Hwan; Song, Myungkwan; Yun, Jungheum

2014-05-29

159

Wet Etching of TiO2-Based Precursor Amorphous Films for Transparent Electrodes  

NASA Astrophysics Data System (ADS)

We investigated wet etching of Nb-doped anatase TiO2 (TNO) transparent conducting thin films and their precursors in an amorphous phase deposited by rf sputtering on glass substrates. The polycrystalline TNO films showed a very low etching rate of less than 0.06 nm/min in concentrated sulfuric acid (H2SO4) even at elevated temperatures up to 95 °C. In contrast, H2SO4 etched the precursor films at a rate of 1.4 nm/min at 95 °C. The etching rate of the amorphous films followed the Arrhenius equation, leading us to conjecture that a much higher etching rate of ˜230 nm/min can be achieved at 170 °C. These results indicate that wet-etching of precursor amorphous films prior to crystallization represents a practical and low-cost lithographic technique for patterning TiO2-based transparent electrodes.

Ohkubo, Junpei; Hirose, Yasushi; Sakai, Enju; Nakao, Shoichiro; Hitosugi, Taro; Hasegawa, Tetsuya

2011-01-01

160

Synthesis of Graphene Films by Chemical Vapor Deposition for Transparent Conducting Electrodes of GaN Light-Emitting Diodes  

NASA Astrophysics Data System (ADS)

This work demonstrales large-scale simultaneous fabrication of patterned graphene-based GaN light-emitting diodes (LEDs). Graphene sheets were synthesized using a chemical vapor deposition (CVD) technique on nickel films and showed typical CVD-synthesized film properties, possessing a sheet resistance of ~605 ?/\\squarelg with a transparency of more than 85% in the 400-800 nm wavelength range, and was applied as transparent condueting electrodes of GaN-based blue LHDs, The light output performance of GaN LEDs with graphene electrodes was comparable to that of conventional ITO-electrode LEDs over the range of input current up to 150 mA.

Jo, Gunho; Choe, Minhyeok; Cho, Chu-Young; Kim, Jin Ho; Park, Woojin; Lee, Sangchul; Park, Seong-Ju; Hong, Byung Hee; Kahng, Yung Ho; Lee, Takhee

2011-12-01

161

Selective-area van der Waals epitaxy of topological insulator grid nanostructures for broadband transparent flexible electrodes.  

PubMed

Broadband transparent electrodes based on a two-dimensional grid of topological insulator Bi2Se3 are synthesized by a facile selective-area van der Waals epitaxy method. These two-dimensional grid electrodes exhibit high uniformity over large area, outstanding mechanical durability, and excellent chemical resistance to environmental perturbations. Remarkably, the topological grid electrode has high transmittance of more than 85% from the visible to the near-infrared region. PMID:24038418

Guo, Yunfan; Aisijiang, Mahaya; Zhang, Kai; Jiang, Wei; Chen, Yulin; Zheng, Wenshan; Song, Zehao; Cao, Jie; Liu, Zhongfan; Peng, Hailin

2013-11-01

162

Enhanced broadband transmission through structured plasmonic thin films for transparent electrodes  

NASA Astrophysics Data System (ADS)

Periodic arrays of subwavelength holes in plasmonic thin films can provide for large broadband transmission in the near-infrared spectrum. The optical transmission properties of these thin films with respect to the film thickness, size, and shape of the holes and the period of the arrays was systematically investigated using finite difference time domain computations. Structured gold and silver films of 20-nm thickness can provide for up to 90% transmittance at near-infrared wavelength, thereby rendering them suitable as transparent conducting electrodes for near-infrared emitters or sensors and photovoltaic applications.

Behera, Gangadhar; Ramakrishna, S. Anantha

2014-01-01

163

Highly stable and flexible silver nanowire-graphene hybrid transparent conducting electrodes for emerging optoelectronic devices.  

PubMed

A new AgNW-graphene hybrid transparent conducting electrode (TCE) was prepared by dry-transferring a chemical vapor deposition (CVD)-grown monolayer graphene onto a pristine AgNW TCE. The AgNW-graphene hybrid TCE exhibited excellent optical and electrical properties as well as mechanical flexibility. The AgNW-graphene hybrid TCE showed highly enhanced thermal oxidation and chemical stabilities because of the superior gas-barrier property of the graphene protection layer. Furthermore, the organic solar cells with the AgNW-graphene hybrid TCE showed excellent photovoltaic performance as well as superior long-term stability under ambient conditions. PMID:23842732

Lee, Donghwa; Lee, Hyungjin; Ahn, Yumi; Jeong, Youngjun; Lee, Dae-Young; Lee, Youngu

2013-09-01

164

Optimization of Transparent Electrode for Solar Cell and Chemical Vapor Deposition of Amorphous Silicon. Final Technical Report, 15 September 1980-30 March 1983.  

National Technical Information Service (NTIS)

Solar photovoltaic cell designs usually benefit from a front surface which is both transparent and highly conductive to electricity. A practical transparent electrode layer must also be durable, stable to weathering and sunlight, inexpensive, nontoxic, no...

R. Gordon J. Proscia F. Ellis S. Kurtz

1984-01-01

165

In Situ Synthesis of NiS Nanowall Networks on Ni Foam as a TCO-Free Counter Electrode for Dye-Sensitized Solar Cells.  

PubMed

Nickel sulfide (NiS) nanowall networks have been prepared by a novel one-step hydrothermal method on a nickel (Ni) foam substrate. The Ni foam has a high conductivity and porous structure. To our knowledge, the Ni foam is used as a conductive substrate for the dye-sensitized solar cell (DSSC) for the first time. The Ni foam is used as not only the conductive substrate but also the Ni sources of the reaction. The Ni foam supported NiS prepared by this simple hydrothermal method shows high catalytic activity for reduction of triiodide ions. The DSSC with a transparent conductive oxide (TCO)-free NiS counter electrode (CE) was herein developed and showed a higher power conversion efficiency of 8.55% than that with a TCO supported NiS CE (7.47%) and a TCO supported platinum CE (7.99%). PMID:24660877

Ke, Weijun; Fang, Guojia; Tao, Hong; Qin, Pingli; Wang, Jing; Lei, Hongwei; Liu, Qin; Zhao, Xingzhong

2014-04-23

166

Counter-ion dependent, longitudinal unzipping of multi-walled carbon nanotubes to highly conductive and transparent graphene nanoribbons.  

PubMed

Here we report for the first time, a simple hydrothermal approach for the bulk production of highly conductive and transparent graphene nanoribbons (GNRs) using several counter ions from K2SO4, KNO3, KOH and H2SO4 in aqueous media, where, selective intercalation followed by exfoliation gives highly conducting GNRs with over 80% yield. In these experiments, sulfate and nitrate ions act as a co-intercalant along with potassium ions resulting into exfoliation of multi-walled carbon nanotubes (MWCNTs) in an effective manner. The striking similarity of experimental results in KOH and H2SO4 that demonstrates partially damaged MWCNTs, implies that no individual K(+), SO4(2-) ion plays a key role in unwrapping of MWCNTs, rather this process is largely effective in the presence of both cations and anions working in a cooperative manner. The GNRs can be used for preparing conductive 16?k?sq(-1), transparent (82%) and flexible thin films using low cost fabrication method. PMID:24621526

Shinde, Dhanraj B; Majumder, Mainak; Pillai, Vijayamohanan K

2014-01-01

167

Highly stable and flexible silver nanowire-graphene hybrid transparent conducting electrodes for emerging optoelectronic devices  

NASA Astrophysics Data System (ADS)

A new AgNW-graphene hybrid transparent conducting electrode (TCE) was prepared by dry-transferring a chemical vapor deposition (CVD)-grown monolayer graphene onto a pristine AgNW TCE. The AgNW-graphene hybrid TCE exhibited excellent optical and electrical properties as well as mechanical flexibility. The AgNW-graphene hybrid TCE showed highly enhanced thermal oxidation and chemical stabilities because of the superior gas-barrier property of the graphene protection layer. Furthermore, the organic solar cells with the AgNW-graphene hybrid TCE showed excellent photovoltaic performance as well as superior long-term stability under ambient conditions.A new AgNW-graphene hybrid transparent conducting electrode (TCE) was prepared by dry-transferring a chemical vapor deposition (CVD)-grown monolayer graphene onto a pristine AgNW TCE. The AgNW-graphene hybrid TCE exhibited excellent optical and electrical properties as well as mechanical flexibility. The AgNW-graphene hybrid TCE showed highly enhanced thermal oxidation and chemical stabilities because of the superior gas-barrier property of the graphene protection layer. Furthermore, the organic solar cells with the AgNW-graphene hybrid TCE showed excellent photovoltaic performance as well as superior long-term stability under ambient conditions. Electronic supplementary information (ESI) available: Detailed electrical connection, mechanical flexibility, and chemical stability tests of the AgNW and AgNW-graphene hybrid TCEs are included. See DOI: 10.1039/c3nr02320f

Lee, Donghwa; Lee, Hyungjin; Ahn, Yumi; Jeong, Youngjun; Lee, Dae-Young; Lee, Youngu

2013-08-01

168

Enhanced performance in dye-sensitized solar cells via carbon nanofibers-platinum composite counter electrodes  

NASA Astrophysics Data System (ADS)

A composite counter electrode (CE) made of electrospun carbon nanofibers (ECNs) and platinum (Pt) nanoparticles has been demonstrated for the first time to improve the performance of dye-sensitized solar cells (DSCs). The new ECN-Pt composite CE exhibited a more efficient electro-catalytic performance with lower charge transfer resistance (Rct), larger surface area, and faster reaction rate than those of conventional Pt. It reduced the overall series resistance (Rse), decreased dark saturation current density (J0) and increased shunt resistance (Rsh) of the DSCs, thereby leading to a higher fill factor (FF) and larger open circuit voltage (Voc). The reduced electron transport resistance (Rs) and faster charge transfer rate in the CE led to a smaller overall cell series resistance (Rse) in the ECN-Pt composite based DSCs. The DSCs based on an ECN-Pt CE achieved a ? of ~8%, which was improved over those of pure Pt or ECN based cells.

Poudel, Prashant; Zhang, Lifeng; Joshi, Prakash; Venkatesan, Swaminathan; Fong, Hao; Qiao, Qiquan

2012-07-01

169

Robust polyaniline-graphene complex counter electrodes for efficient dye-sensitized solar cells.  

PubMed

With an aim of accelerating the charge transfer between polyaniline (PANi) and graphene, polyaniline-graphene (PANi-graphene) complexes are synthesized by a reflux technique and employed as counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). Because of the easy charge-transfer between PANi (N atoms) and graphene (C atoms) by a covalent bond, electrical conduction and electrocatalysis of PANi-graphene complex CEs, and therefore power conversion efficiency of their DSSCs have been elevated in comparison with that of PANi-only CE. The resultant PANi-graphene complex CEs are characterized by spectral analysis, morphology observation, and electrochemical tests. The DSSC employing PANi-8 wt ‰ graphene complex CE gives an impressive power conversion efficiency of 7.78%, which is higher than 6.24% from PANi-only and 6.52% from Pt-only CE-based DSSCs. PMID:24826943

He, Benlin; Tang, Qunwei; Wang, Min; Chen, Haiyan; Yuan, Shuangshuang

2014-06-11

170

PtRu nanofiber alloy counter electrodes for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

With an aim of enhancing the light-to-electric power conversion efficiency of dye-sensitized solar cell (DSSC), here we synthesize PtRu nanofiber alloys using a low-temperature hydrothermal technique which are employed as counter electrodes (CEs) for DSSCs. Owing to the good electrical conduction and electrocatalysis, light-to-electric power conversion efficiencies of PtRu-based DSSCs have been elevated in comparison with that of Pt CE based DSSC. The DSSC employing PtRu3 alloy CE gives a power conversion efficiency of 6.80% in comparison with 6.17% from Pt-based DSSC. The reasonable conversion efficiency, simple preparation, and scalability demonstrate the potential use of PtRu alloys in efficient DSSCs.

Cai, Hongyuan; Tang, Qunwei; He, Benlin; Li, Pinjiang

171

Highly efficient and bendable organic solar cells using a three-dimensional transparent conducting electrode  

NASA Astrophysics Data System (ADS)

A three-dimensional (3D) transparent conducting electrode, consisting of a quasi-periodic array of discrete indium-tin-oxide (ITO) nanoparticles superimposed on a highly conducting oxide-metal-oxide multilayer using ITO and silver oxide (AgOx) as oxide and metal layers, respectively, is synthesized on a polymer substrate and used as an anode in highly flexible organic solar cells (OSCs). The 3D electrode is fabricated using vacuum sputtering sequences to achieve self-assembly of distinct ITO nanoparticles on a continuous ITO-AgOx-ITO multilayer at room-temperature without applying conventional high-temperature vapour-liquid-solid growth, solution-based nanoparticle coating, or complicated nanopatterning techniques. Since the 3D electrode enhances the hole-extraction rate in OSCs owing to its high surface area and low effective series resistance for hole transport, OSCs based on this 3D electrode exhibit a power conversion efficiency that is 11-22% higher than that achievable in OSCs by means of conventional planar ITO film-type electrodes. A record high efficiency of 6.74% can be achieved in a bendable OSC fabricated on a poly(ethylene terephthalate) substrate.A three-dimensional (3D) transparent conducting electrode, consisting of a quasi-periodic array of discrete indium-tin-oxide (ITO) nanoparticles superimposed on a highly conducting oxide-metal-oxide multilayer using ITO and silver oxide (AgOx) as oxide and metal layers, respectively, is synthesized on a polymer substrate and used as an anode in highly flexible organic solar cells (OSCs). The 3D electrode is fabricated using vacuum sputtering sequences to achieve self-assembly of distinct ITO nanoparticles on a continuous ITO-AgOx-ITO multilayer at room-temperature without applying conventional high-temperature vapour-liquid-solid growth, solution-based nanoparticle coating, or complicated nanopatterning techniques. Since the 3D electrode enhances the hole-extraction rate in OSCs owing to its high surface area and low effective series resistance for hole transport, OSCs based on this 3D electrode exhibit a power conversion efficiency that is 11-22% higher than that achievable in OSCs by means of conventional planar ITO film-type electrodes. A record high efficiency of 6.74% can be achieved in a bendable OSC fabricated on a poly(ethylene terephthalate) substrate. Electronic supplementary information (ESI) available: FE-SEM images of Ar plasma-treated PET surfaces, curve deconvolution of XPS Ag 3d5/2 spectra, refractive indices and extinction coefficients of the Ag and AgOx (O/Ag = 10 at%), changes in the specular reflections of the IAOI-NPA and IAI-NPA electrodes for different O/Ag atomic ratios and thicknesses of the AgOx layer, and comparisons between the Jsc values determined from simulated AM 1.5G illumination and IPCE spectra. See DOI: 10.1039/c3nr06755f

Wang, Wei; Bae, Tae-Sung; Park, Yeon Hyun; Kim, Dong Ho; Lee, Sunghun; Min, Guanghui; Lee, Gun-Hwan; Song, Myungkwan; Yun, Jungheum

2014-05-01

172

Nanopatterned conductive polymer films as a Pt, TCO-free counter electrode for low-cost dye-sensitized solar cells.  

PubMed

A low-cost nanopatterned highly conductive poly(3,4-ethylenedioxythiophene) (PEDOT) thin film was fabricated on a flexible plastic substrate via a chemical polymerization method combined with a nanoimprinting technique and used as a platinum (Pt), TCO-free counter electrode for dye-sensitized solar cells (DSSCs). The catalytic properties of the nanopatterned PEDOT as the counter electrode in DSSCs were studied using cyclic voltammetry, J-V measurements, impedance spectroscopy, and finite-difference time-domain (FDTD) simulations. The nanopatterned PEDOT counter electrodes exhibit better functionality as a counter electrode for tri-iodide reduction when compared to non-patterned PEDOT-based counter electrodes. The Pt and TCO-free DSSCs with a nanopatterned PEDOT-based counter electrode exhibited a power conversion efficiency of 7.1% under one sunlight illumination (100 mW cm(-2)), which is comparable to that of conventional DSSCs with standard platinum Pt/FTO paired counter electrodes. The ability to modulate catalytic functionality with changes in nanoscale morphology represents a promising route for developing new counter electrodes of Pt and TCO-free DSSCs. PMID:23852259

Kwon, Jeong; Ganapathy, Veerappan; Kim, Young Hun; Song, Kyung-Deok; Park, Hong-Gyu; Jun, Yongseok; Yoo, Pil J; Park, Jong Hyeok

2013-09-01

173

Transparent conductive electrodes of mixed TiO2-x-indium tin oxide for organic photovoltaics  

NASA Astrophysics Data System (ADS)

A transparent conductive electrode of mixed titanium dioxide (TiO2-x)-indium tin oxide (ITO) with an overall reduction in the use of indium metal is demonstrated. When used in organic photovoltaic devices based on bulk heterojunction photoactive layer of poly (3-hexylthiophene) and [6,6]-phenyl C61 butyric acid methyl ester, a power conversion efficiency of 3.67% was obtained, a value comparable to devices having sputtered ITO electrode. Surface roughness and optical efficiency are improved when using the mixed TiO2-x-ITO electrode. The consumption of less indium allows for lower fabrication cost of such mixed thin film electrode.

Lee, Kyu-Sung; Lim, Jong-Wook; Kim, Han-Ki; Alford, T. L.; Jabbour, Ghassan E.

2012-05-01

174

A novel hierarchical Pt- and FTO-free counter electrode for dye-sensitized solar cell  

PubMed Central

A novel hierarchical Pt- and FTO-free counter electrode (CE) for the dye-sensitized solar cell (DSSC) was prepared by spin coating the mixture of TiO2 nanoparticles and poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) solution onto the glass substrate. Compared with traditional Pt/FTO CE, the cost of the new CE is dramatically reduced by the application of bilayer TiO2-PEDOT:PSS/PEDOT:PSS film and the glass substrate. The sheet resistance of this composite film is 35 ? sq?1 and is low enough to be used as an electrode. The surface morphologies of TiO2-PEDOT:PSS layer and modified PEDOT:PSS layer were characterized by scanning electron microscope, which shows that the former had larger surface areas than the latter. Electrochemical impedance spectra and Tafel polarization curves prove that the catalytic activity of TiO2-PEDOT:PSS/PEDOT:PSS/glass CE is higher than that of PEDOT:PSS/FTO CE and is similar to Pt/FTO CE's. This new fabricated device with TiO2-PEDOT:PSS/PEDOT:PSS/glass CE achieves a high power conversion efficiency (PCE) of 4.67%, reaching 91.39% of DSSC with Pt/FTO CE (5.11%).

2014-01-01

175

A novel hierarchical Pt- and FTO-free counter electrode for dye-sensitized solar cell.  

PubMed

A novel hierarchical Pt- and FTO-free counter electrode (CE) for the dye-sensitized solar cell (DSSC) was prepared by spin coating the mixture of TiO2 nanoparticles and poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) solution onto the glass substrate. Compared with traditional Pt/FTO CE, the cost of the new CE is dramatically reduced by the application of bilayer TiO2-PEDOT:PSS/PEDOT:PSS film and the glass substrate. The sheet resistance of this composite film is 35 ? sq(-1) and is low enough to be used as an electrode. The surface morphologies of TiO2-PEDOT:PSS layer and modified PEDOT:PSS layer were characterized by scanning electron microscope, which shows that the former had larger surface areas than the latter. Electrochemical impedance spectra and Tafel polarization curves prove that the catalytic activity of TiO2-PEDOT:PSS/PEDOT:PSS/glass CE is higher than that of PEDOT:PSS/FTO CE and is similar to Pt/FTO CE's. This new fabricated device with TiO2-PEDOT:PSS/PEDOT:PSS/glass CE achieves a high power conversion efficiency (PCE) of 4.67%, reaching 91.39% of DSSC with Pt/FTO CE (5.11%). PMID:24808802

Zhao, Xing; Li, Meicheng; Song, Dandan; Cui, Peng; Zhang, Zhirong; Zhao, Yan; Shen, Chao; Zhang, Zhaohuang

2014-01-01

176

A novel hierarchical Pt- and FTO-free counter electrode for dye-sensitized solar cell  

NASA Astrophysics Data System (ADS)

A novel hierarchical Pt- and FTO-free counter electrode (CE) for the dye-sensitized solar cell (DSSC) was prepared by spin coating the mixture of TiO2 nanoparticles and poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) solution onto the glass substrate. Compared with traditional Pt/FTO CE, the cost of the new CE is dramatically reduced by the application of bilayer TiO2-PEDOT:PSS/PEDOT:PSS film and the glass substrate. The sheet resistance of this composite film is 35 ? sq-1 and is low enough to be used as an electrode. The surface morphologies of TiO2-PEDOT:PSS layer and modified PEDOT:PSS layer were characterized by scanning electron microscope, which shows that the former had larger surface areas than the latter. Electrochemical impedance spectra and Tafel polarization curves prove that the catalytic activity of TiO2-PEDOT:PSS/PEDOT:PSS/glass CE is higher than that of PEDOT:PSS/FTO CE and is similar to Pt/FTO CE's. This new fabricated device with TiO2-PEDOT:PSS/PEDOT:PSS/glass CE achieves a high power conversion efficiency (PCE) of 4.67%, reaching 91.39% of DSSC with Pt/FTO CE (5.11%).

Zhao, Xing; Li, Meicheng; Song, Dandan; Cui, Peng; Zhang, Zhirong; Zhao, Yan; Shen, Chao; Zhang, Zhaohuang

2014-05-01

177

Fabrication of Transparent and Flexible Organic Field-Effect Transistors with Solution-Processed Graphene Source--Drain and Gate Electrodes  

Microsoft Academic Search

Transparent organic field-effect transistors with solution-processed graphene source--drain and gate electrodes were fabricated on flexible substrates. Graphene electrodes were formulated by chemical and thermal reduction of solution-processed graphene oxide films. A graphene gate electrode, a gate dielectric layer, and an organic active layer were coated on a transparent flexible polyimide film. Next, graphene source--drain electrodes, which had been formed on

Koichi Suganuma; Shunichiro Watanabe; Takuya Gotou; Keiji Ueno

2011-01-01

178

Spectroscopic and Electrochemical Characterization of Nanostructured Optically-Transparent Carbon Electrodes  

PubMed Central

The present paper describes the results related to the optical and electrochemical characterization of thin carbon films fabricated by spin coating and pyrolysis of AZ P4330-RS photoresist. The goal of this paper is to provide comprehensive information allowing for the rational the selection of the conditions to fabricate optically-transparent carbon electrodes (OTCE) with specific electro-optical properties. According to our results, these electrodes could be appropriate choices as electrochemical transducers to monitor electrophoretic separations. At the core of this manuscript is the development and critical evaluation of a new optical model to calculate the thickness of the OTCE by variable angle spectroscopic ellipsometry (VASE). Such data was complemented with topography and roughness (obtained by AFM), electrochemical properties (obtained by cyclic voltammetry), electrical properties (obtained by electrochemical impedance spectroscopy), and structural composition (obtained by Raman spectroscopy). Although the described OTCE were used as substrates to investigate the effect of electrode potential on the real-time adsorption of proteins by ellipsometry, these results could enable the development of other biosensors that can be then integrated into various CE platforms.

Benavidez, Tomas E.; Garcia, Carlos D.

2013-01-01

179

Multiscale transparent electrode architecture for efficient light management and carrier collection in solar cells.  

PubMed

The challenge for all photovoltaic technologies is to maximize light absorption, to convert photons with minimal losses into electric charges, and to efficiently extract them to the electrical circuit. For thin-film solar cells, all these tasks rely heavily on the transparent front electrode. Here we present a multiscale electrode architecture that allows us to achieve efficiencies as high as 14.1% with a thin-film silicon tandem solar cell employing only 3 ?m of silicon. Our approach combines the versatility of nanoimprint lithography, the unusually high carrier mobility of hydrogenated indium oxide (over 100 cm(2)/V/s), and the unequaled light-scattering properties of self-textured zinc oxide. A multiscale texture provides light trapping over a broad wavelength range while ensuring an optimum morphology for the growth of high-quality silicon layers. A conductive bilayer stack guarantees carrier extraction while minimizing parasitic absorption losses. The tunability accessible through such multiscale electrode architecture offers unprecedented possibilities to address the trade-off between cell optical and electrical performance. PMID:22332666

Boccard, Mathieu; Battaglia, Corsin; Hänni, Simon; Söderström, Karin; Escarré, Jordi; Nicolay, Sylvain; Meillaud, Fanny; Despeisse, Matthieu; Ballif, Christophe

2012-03-14

180

A study of TiO2/carbon black composition as counter electrode materials for dye-sensitized solar cells  

PubMed Central

This study describes a systematic approach of TiO2/carbon black nanoparticles with respect to the loading amount in order to optimize the catalytic ability of triiodide reduction for dye-sensitized solar cells. In particular, the cell using an optimized TiO2 and carbon black electrode presents an energy conversion efficiency of 7.4% with a 5:1 ratio of a 40-nm TiO2 to carbon black. Based on the electrochemical analysis, the charge-transfer resistance of the carbon counter electrode changed based on the carbon black powder content. Electrochemical impedance spectroscopy and cyclic voltammetry study show lower resistance compared to the Pt counter electrode. The obtained nanostructures and photo electrochemical study were characterized.

2013-01-01

181

Synergistic catalytic effect of a composite (CoS/PEDOT:PSS) counter electrode on triiodide reduction in dye-sensitized solar cells.  

PubMed

Inorganic/organic nanocomposite counter electrodes comprised of sheetlike CoS nanoparticles dispersed in polystyrenesulfonate-doped poly(3,4-ethylenedioxythiophene (CoS/PEDOT:PSS) offer a synergistic effect on catalytic performance toward the reduction of triiodide for dye-sensitized solar cells (DSSCs), yielding 5.4% power conversion efficiency, which is comparable to that of the conventional platinum counter electrode (6.1%). The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry measurements revealed that the composite counter electrodes exhibited better catalytic activity, fostering rate of triiodide reduction, than that of pristine PEDOT: PSS electrode. The simple preparation of composite (CoS/PEDOT:PSS) electrode at low temperature with improved electrocatalytic properties are feasible to apply in flexible substrates, which is at most urgency for developing novel counter electrodes for lightweight flexible solar cells. PMID:21568263

Sudhagar, P; Nagarajan, S; Lee, Yong-Gun; Song, Donghoon; Son, Taewook; Cho, Woohyung; Heo, Miyoung; Lee, Kyoungjun; Won, Jongok; Kang, Yong Soo

2011-06-01

182

Light energy conversion with pheophytin a monolayer at the SnO[sub 2] optically transparent electrode  

SciTech Connect

The photoelectrochemical, absorption and fluorescence properties of pheophytin a mono- and multilayers, deposited on optically transparent tin oxide electrodes and quartz slides were investigated. Spectra of photocurrents coincided with the absorption spectra of photosynthetic pigment in monolayers at the SnO[sub 2]/solution interfaces. The anodic and cathodic photocurrents were measured at various electrode potentials. Effects of pH, electrode potentials, and concentration of redox reagents on the conversion of solar energy in monolayers on optically transparent electrodes are discussed. The absorption and fluorescence spectral characteristics, and fluorescence lifetime measurements of pheophytin a in monolayers and thin films are also discussed in view of the aggregation properties of the photosynthetic pigment. The thermodynamics of adsorption of large amphiphilic compounds at the interface between two immiscible liquids is considered. The adsorption behavior of pheophytin a dissolved in different solvents is investigated. The thermodynamic parameters of pheophytin a adsorption at octane/water and benzene/water interfaces were determined.

Volkov, A.G. (Univ. of California, Davis, CA (United States)); Markin, V.S. (Univ. of Texas, Dallas, TX (United States)); Leblanc R.M.; Gugeshashvili, M.I.; Zelent, B.; Munger, G. (Universite du Quebec a Trois-Riveres, Quebec (Canada))

1994-02-01

183

Low-temperature self-assembled vertically aligned carbon nanofibers as counter-electrode material for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Low-temperature AC-DC PECVD is employed for direct growth of vertically aligned carbon nanofibers (VACNFs) on ordinary transparent conductive glass as counter-electrode material for dye-sensitized solar cells (DSSCs). To the best of our knowledge, this is the first report on utilization of VACNFs grown directly on ordinary FTO-coated glass as a cost-effective catalyst material in DSSCs. According to the FESEM images, the as-grown arrays are well aligned and dense, and offer uniform coverage on the surface of the substrate. In-plane and out-of-plane conductivity measurements reveal their good electrical conductivity, and Raman spectroscopy suggests a high number of electrocatalytic active sites, favoring charge transport at the electrolyte/electrode interface. Hybrid VACNF/Pt electrodes are also fabricated for performance comparison with Pt and VACNF electrodes. X-ray diffraction results verify the crystallization of Pt in hybrid electrodes and further confirm the vertical alignment of carbon nanofibers. Electrochemical characterization indicates that VACNFs provide both high catalytic and good charge transfer capability, which can be attributed to their high surface area, defect-rich and one-dimensional structure, vertical alignment and low contact resistance. As a result, VACNF cells can achieve a comparable performance (˜5.6%) to that of the reference Pt cells (˜6.5%). Moreover, by combination of the excellent charge transport and catalytic ability of VACNFs and the high conductivity of Pt nanoparticles, hybrid VACNF/Pt cells can deliver a performance superior to that of the Pt cells (˜7.2%), despite having a much smaller amount of Pt loading, which raises hopes for low-cost large-scale production of DSSCs in the future.

Mahpeykar, S. M.; Tabatabaei, M. K.; Ghafoori-fard, H.; Habibiyan, H.; Koohsorkhi, J.

2013-11-01

184

Spectroelectrochemical characterization of ultra-thin films formed by electropolymerization of phenothiazine derivatives on transparent gold electrodes  

Microsoft Academic Search

Transparent gold electrodes covered with an ultra-thin polyphenothiazine film layer have been obtained by electropolymerization of the monomeric parent compounds, Methylene Blue, Methylene Green and Azur A, under alkaline pH conditions. The electrochemical behaviour of the polymers immobilized on the electrode surface has been characterized by UV-visible difference spectroelectrochemistry. A study of the dependence of the oxidation state of the

Daniela D. Schlereth; Wolfgang Schuhmann; Hanns-Ludwig Schmidt

1995-01-01

185

Transparent, highly conductive graphene electrodes from acetylene-assisted thermolysis of graphite oxide sheets and nanographene molecules  

Microsoft Academic Search

Transparent and highly conductive graphene electrodes have been fabricated through acetylene-assisted thermolysis of graphite oxide (GO) sheets. This novel procedure uses acetylene as a supplemental carbon source to repair substantial defects within GO sheets, leading to the enhancement of graphitization of synthesized graphene electrodes. The as-prepared graphene on quartz substrates exhibits an electrical conductivity of 1425 S cm-1 with an

Yanyu Liang; Johannes Frisch; Linjie Zhi; Hassan Norouzi-Arasi; Xinliang Feng; Jürgen P. Rabe; Norbert Koch; Klaus Müllen

2009-01-01

186

Equivalent circuit modeling of metal-semiconductor-metal photodiodes with transparent conductor electrodes  

NASA Astrophysics Data System (ADS)

Metal-semiconductor-metal (MSM) photodiodes with electrodes fabricated from the transparent conductor cadmium tin oxide (CTO) have been shown to double photoresponsivity. Their bandwidths, however, are significantly lower than those of MSMs fabricated with standard Ti/Au contacts. Though MSMs are generally believed to be limited by the transit time of electrons, it is possible the larger resistivity of CTO has become a significant factor, making the MSMs RC time constant limited instead. Previous models of MSMs only account for one of the two back-to-back Schottky diodes. A new model which takes into account both the forward and reverse biased junctions has been developed from the small signal model of a Schottky diode. This new model was fit to data obtained from S-parameter measurements, and incorporates both the transit time response and RC time constant response.

Rommel, Sean L.; Erby, David N.; Gao, Wei; Berger, Paul R.; Zydzik, George J.; Rhodes, W. W.; O'Bryan, H. M.; Sivco, Deborah L.; Cho, Alfred Y.

1997-04-01

187

Metal-Free Graphene as Transparent Electrode for GaN-Based Light-Emitters  

NASA Astrophysics Data System (ADS)

Graphene contacts to p-GaN are considered as an alternative to indium--tin-oxide transparent electrodes in GaN based vertical-cavity surface-emitting lasers (VCSELs). Contact properties were investigated on light-emitting diode and p-GaN test structures, where dielectric apertures were used to eliminate the influence of the metal pads used to bias the contacts. Using single layer graphene we were able to operate light emitting diodes with current densities of 300 A/cm2. Addition of a second layer of graphene increased the maximum bias current to 1 kA/cm2. However, the contacts are non-linear and cannot withstand high current densities for a long time. The results are promising but further investigation and improvement is needed for graphene to be a viable alternative to indium--tin-oxide for blue VCSELs.

Stattin, Martin; Rosa, Cesar Lockhart de la; Sun, Jie; Yurgens, August; Haglund, Åsa

2013-08-01

188

Solution processed metallic nanowire based transparent electrode capped with a multifunctional layer  

NASA Astrophysics Data System (ADS)

Solution processed metallic nanowires (NWs) have been attracting increasing attention because of the effective combination of electrical and optical properties. However, they still suffer from several drawbacks, including large surface roughness, instability against oxidation and moisture, and poor adhesion to the substrate. These factors need to be addressed for the wide-spread use of metallic NWs as transparent electrodes. In this work, we demonstrate that by using a solution processed zinc oxide (ZnO) capping layer, NW films show improved electro-optical properties, adhesion, and mechanical flexibility. In addition, the ZnO film reduces the surface roughness by more than half of its initial value, provides protection against oxidation, coalescence at high temperature, damp-heat conditions, and even extreme chemical environments.

Ghosh, D. S.; Chen, T. L.; Mkhitaryan, V.; Formica, N.; Pruneri, V.

2013-06-01

189

Fully-sprayed and flexible organic photodiodes with transparent carbon nanotube electrodes.  

PubMed

In this study, we demonstrate the feasibility of TCO-free, fully sprayed organic photodiodes on flexible polyethylene terephthalate (PET) substrates. Transparent conducting films of single-wall carbon nanotubes are spray deposited from aqueous solutions. Low roughness is achieved, and films with sheet resistance values of 160 ?/sq at 84% in transmittance are fabricated. Process issues related to the wetting of CNTs are then examined and solved, enabling successive spray depositions of a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer and a blend of regioregular poly(3-hexylthiophene-2,5-diyl) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM). The active layer is then optimized, achieving a process yield above 90% and dark currents as low as 10(-4) mA/cm(2). An external quantum efficiency of 65% and high reproducibility in the performance of the devices are obtained. Finally, the impact of the characteristics of the transparent electrode (transmittance and sheet resistance) on the performances of the device are investigated and validated through a theoretical model and experimental data. PMID:24914700

Falco, Aniello; Cinà, Lucio; Scarpa, Giuseppe; Lugli, Paolo; Abdellah, Alaa

2014-07-01

190

Electrospray deposition of carbon nanotube thin films for flexible transparent electrodes.  

PubMed

Flexible transparent carbon nanotube (CNT) electrodes were fabricated by electrospray deposition, a large-area scalable and cost-effective process. The carbon nanotubes were dispersed in N,N-dimethylformamide (DMF) and deposited on polyethylene terephthalate (PET) substrates by electrospray deposition process at room temperature and atmospheric pressure. Major process variables were characterized and optimized for the electrospray process development such as electric field between nozzle and substrates, CNT solution flowrate, gap between nozzle and substrates, solution concentration, solvent properties and surface temperature. The sheet resistance of the electrospray deposited CNT films were reduced by HNO3 doping process. 169 Omega/sq sheet resistance and 86% optical transmittance was achieved with low surface roughness of 1.2 nm. The films showed high flexibility and transparency, making them potential replacements of ITO or ZnO in such as solid state lighting, touch panels, and solar cells. Electrospray process is a scalable process and we believe that this process can be applied for large area carbon nanotube film formation. PMID:24205613

Meng, Yinan; Xin, Guoqing; Nam, Jaewook; Cho, Sung Min; Chae, Heeyeop

2013-09-01

191

Transparent conducting oxides for electrode applications in light emitting and absorbing devices  

NASA Astrophysics Data System (ADS)

In both light emitting devices such as light emitting diodes (LEDs), and light absorbing devices such as solar cells (also photodetectors), which are gaining considerable interest for their energy saving and energy production capability, respectively, a compromise must be struck between the need to increase the light emitting/absorbing area/potential and the need for low series resistance of the metal contact grid. This undesirable compromise can be mitigated by using transparent conducting oxides (TCOs), which heretofore have been dominated by ITO (indium tin oxide—an In-rich alloy of indium oxide and tin oxide). Due to the expected scarcity of Indium used in ITO, efforts are underway to develop indium-free TCOs for the above-mentioned devices as well as flat panel displays. ZnO heavily doped with Ga or Al (GZO or AZO) is becoming a very attractive candidate for future generation TCOs. GZO and AZO as well as multilayer TCOs consisting of two TCO layers with a thin metal layer in between have been widely investigated for LEDs and solar cells to enhance device performance. This article succinctly reviews the latest developments in and properties of TCOs, particularly in relation to thin film transparent electrode applications for LEDs and solar cells. Pertinent critical issues and possible solutions are provided as well.

Liu, Huiyong; Avrutin, V.; Izyumskaya, N.; Özgür, Ü.; Morkoç, H.

2010-11-01

192

High-performance/low-temperature-processed dye solar cell counter electrodes based on chromium substrates with cube-like morphology  

NASA Astrophysics Data System (ADS)

There is still an open question of how to prepare high-performance counter electrodes for dye solar cells (DSCs) at room temperature; a requirement for flexible DSCs. Here, we introduce Pt deposited cube-like chromium coating as a low-temperature highly-efficient counter electrode for DSCs. Cr is a chemically stable metal and can be easily electroplated on conductive substrates with high roughness (here ?160 nm) and cube-like appearance. A cyclic electrochemical deposition method with optimized temperature and number of cycles is used to grow Pt nanoparticles on this surface and charge transfer resistance as low as 0.54 ? cm2 and 0.27 ? cm2 were obtained at 40 °C and 55 °C solution temperatures, respectively. More surface defects (kinks, terraces and ledges) on the cube-like chromium film, as well as the electric field enhancement near the cube edges produces more dispersed Pt nanoparticles on this substrate compared to FTO (fluorine doped tin oxide) substrate. By replacing the conventional DSC counter electrode (thermal Pt on FTO) with this new electrode, filling factor and efficiency increase from 0.63-6.6% to 0.68-8.77%, without a scattering film. The efficiency can be as high as 9.52% by using a scattering film.

Behrouznejad, Fatemeh; Taghavinia, Nima

193

A cracked polymer templated metal network as a transparent conducting electrode for ITO-free organic solar cells.  

PubMed

We report a highly transparent, low resistance Ag metal network templated by a cracked polymer thin film and its incorporation in an organic solar cell. The performance of this scalable metallic network is comparable to that of conventional ITO electrodes. This is a general approach to replace ITO in diverse thin film devices. PMID:24958552

Rao, K D M; Hunger, Christoph; Gupta, Ritu; Kulkarni, Giridhar U; Thelakkat, Mukundan

2014-08-01

194

Fully transparent InGaZnO thin film transistors using indium tin oxide\\/graphene multilayer as source\\/drain electrodes  

Microsoft Academic Search

Demonstration of a transparent InGaZnO thin film transistor using a graphene composite as the transparent source\\/drain electrode is presented. Graphene growth was confirmed by Raman spectroscopy, showing all associated peaks at 1350, 1580, and 2700 cm-1. The graphene composite showed a sheet resistance reduction of 15% while losing only 1.2% transparency when compared to the reference indium-tin oxide only electrode.

David Seo; Sanghun Jeon; Sunae Seo; Ihun Song; Changjung Kim; Sungho Park; James S. Harris; U.-In Chung

2010-01-01

195

Potential-assisted adsorption of bovine serum albumin onto optically transparent carbon electrodes.  

PubMed

This article describes the effect of the applied potential on the adsorption of bovine serum albumin (BSA) to optically transparent carbon electrodes (OTCE). To decouple the effect of the applied potential from the high affinity of the protein for the bare surface, the surface of the OTCE was initially saturated with a layer of BSA. Experiments described in the article show that potential values higher than +500 mV induced a secondary adsorption process (not observed at open-circuit potential), yielding significant changes in the thickness (and adsorbed amount) of the BSA layer obtained. Although the process showed a significant dependence on the experimental conditions selected, the application of higher potentials, selection of pH values around the isoelectric point (IEP) of the protein, high concentrations of protein, and low ionic strengths yielded faster kinetics and the accumulation of larger amounts of protein on the substrate. These experiments, obtained around the IEP of the protein, contrast with the traditional hypothesis that enhanced electrostatic interactions between the polarized substrate and the (oppositely charged) protein are solely responsible for the enhanced adsorption. These results suggest that the potential applied to the electrode is able to polarize the adsorbed layer and induce dipole-dipole interactions between the adsorbed and the incoming protein. This mechanism could be responsible for the potential-dependent oversaturation of the surface and could bolster to the development of surfaces with enhanced catalytic activity and implants with improved biocompatibility. PMID:24156567

Benavidez, Tomás E; Garcia, Carlos D

2013-11-19

196

Economical Pt-free catalysts for counter electrodes of dye-sensitized solar cells.  

PubMed

Three classes (carbides, nitrides and oxides) of nanoscaled early-transition-metal catalysts have been proposed to replace the expensive Pt catalyst as counter electrodes (CEs) in dye-sensitized solar cells (DSCs). Of these catalysts, Cr(3)C(2), CrN, VC(N), VN, TiC, TiC(N), TiN, and V(2)O(3) all showed excellent catalytic activity for the reduction of I(3)(-) to I(-) in the electrolyte. Further, VC embedded in mesoporous carbon (VC-MC) was prepared through in situ synthesis. The I(3)(-)/I(-) DSC based on the VC-MC CE reached a high power conversion efficiency (PCE) of 7.63%, comparable to the photovoltaic performance of the DSC using a Pt CE (7.50%). In addition, the carbide catalysts demonstrated catalytic activity higher than that of Pt for the regeneration of a new organic redox couple of T(2)/T(-). The T(2)/T(-) DSCs using TiC and VC-MC CEs showed PCEs of 4.96 and 5.15%, much higher than that of the DSC using a Pt CE (3.66%). This work expands the list of potential CE catalysts, which can help reduce the cost of DSCs and thereby encourage their fundamental research and commercial application. PMID:22280185

Wu, Mingxing; Lin, Xiao; Wang, Yudi; Wang, Liang; Guo, Wei; Qi, Daidi; Peng, Xiaojun; Hagfeldt, Anders; Grätzel, Michael; Ma, Tingli

2012-02-22

197

Platinum-graphene counter electrodes for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

This paper describes the photovoltaic performance of dye-sensitized solar cells (DSSCs) containing graphene-incorporated counter electrodes (CEs). The location and thickness of graphene in CEs are optimized to improve the photovoltaic performance of DSSCs, compared with typical Pt CEs. The DSSC, with a Pt/few-layer graphene (FLG) CE, achieved 8% in short-circuit current density and 13% in power conversion efficiency (PCE). Electrochemical impedance spectroscopy shows that the DSSC, with a Pt/FLG CE, exhibits a series resistance lower than that with a Pt CE. The lower series resistance is attributed to the contact resistance at the interface of platinum and fluorine doped tin oxide. The contact resistance is reduced by the formation of the thin platinum-carbon composite layer. It is demonstrated that the consumption of Pt could be reduced with a Pt/FLG CE. However, graphene/Pt CEs resulted in a slow charge-transfer process and consequently a worse photovoltaic performance of DSSCs.

Cheng, Cheng-En; Lin, Chi-Yuan; Shan, Chien-Hsun; Tsai, Shang-Yi; Lin, Ko-Wei; Chang, Chen-Shiung; Shih-Sen Chien, Forest

2013-07-01

198

Low-cost CoPt alloy counter electrodes for efficient dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its merits on clean, low fabrication cost, relatively high power conversion efficiency, good durability, and easy assembly. However, the commercial application of DSSCs has been hindered by the high expenses of counter electrodes (CEs). With an aim of significantly enhancing the light-to-electric power conversion efficiency, here we pioneerly synthesize CoPt alloys using an electrochemically codeposition technique which are employed as CEs for efficient DSSCs. Owing to the rapid charge transfer, electrical conduction, and electrocatalysis, power conversion efficiencies of CoPt alloy CE-based DSSCs have been markedly elevated in comparison with that of the DSSC from Pt-only CE. The DSSC employing CoPt0.1 alloy CE gives an impressive power conversion efficiency of 9.59%, which is much higher than 6.86% from conversional Pt-based DSSC. The high conversion efficiency, low cost in combination with simple preparation, and scalability demonstrates the potential use of CoPt alloy CEs in efficient DSSCs.

He, Benlin; Meng, Xin; Tang, Qunwei; Li, Pinjiang; Yuan, Shuangshuang; Yang, Peizhi

199

Transparent Conducting Nb-Doped TiO2 Electrodes Activated by Laser Annealing for Inexpensive Flexible Organic Solar Cells  

NASA Astrophysics Data System (ADS)

A KrF excimer laser (? = 248 nm) has been adopted for annealing cost-effective Nb-doped TiO2 (NTO) films. Sputtered NTO layers were annealed on SiO2-coated flexible poly(ethylene terephthalate) (PET) substrates. This local laser annealing technique is very useful for the formation of anatase NTO electrodes used in flexible organic solar cells (OSCs). An amorphous NTO film with a high resistivity and a low transparency was transformed significantly into a conductive and transparent anatase NTO electrode by laser irradiation. The 210 nm anatase NTO film shows a sheet resistance of 50 ? and an average optical transmittance of 83.5% in the wavelength range from 450 to 600 nm after annealing at 0.25 J/cm2. The activation of Nb dopants and the formation of the anatase phase contribute to the high conductivity of the laser-annealed NTO electrode. Nb activation causes an increase in the optical band gap due to the Burstein--Moss effect. The electrical properties are in agreement with the material characteristics determined by X-ray diffraction (XRD) analysis and secondary ion mass spectrometry (SIMS). The irradiation energy for the NTO electrode also affects the performance of the organic solar cell. The laser annealing technique provides good properties of the anatase NTO film used as a transparent electrode for flexible organic solar cells (OSCs) without damage to the PET substrate or layer delamination from the substrate.

Lee, Jung-Hsiang; Lin, Chia-Chi; Lin, Yi-Chang

2012-01-01

200

Graphene quantum-dot-doped polypyrrole counter electrode for high-performance dye-sensitized solar cells.  

PubMed

Herein graphene quantum dot (GQD), a graphene material with lateral dimension less than 100 nm, is explored to dope PPy on F-doped tin oxide glass as an efficient counter electrode for high-performance dye-sensitized solar cells (DSSCs). The GQDs-doped PPy film has a porous structure in comparison to the densely structured plain PPy, and displays higher catalytic current density and lower charge transfer resistance than the latter toward I3(-)/I(-) redox reaction. The highest power conversion efficiency (5.27%) for DSSCs is achieved with PPy doped with10% GQDs, which is comparable to that of Pt counter electrode-based DSSCs. This work provides an inexpensive alternative to replace platinum for DSSCs. PMID:23448248

Chen, Lijia; Guo, Chun Xian; Zhang, Qiaoming; Lei, Yanlian; Xie, Jiale; Ee, Shujing; Guai, Guanhong; Song, Qunliang; Li, Chang Ming

2013-03-01

201

FeSe2 films with controllable morphologies as efficient counter electrodes for dye-sensitized solar cells.  

PubMed

The FeSe2 films with controllable morphologies (including 3D flower-like and sphere-shaped) have been applied as the counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). It is found that 3D flower-like FeSe2 CEs perform comparably to conventional platinum CEs (power conversion efficiencies of 8.00 and 7.87%, respectively). PMID:24468707

Wang, Wenjun; Pan, Xu; Liu, Weiqing; Zhang, Bing; Chen, Haiwei; Fang, Xiaqin; Yao, Jianxi; Dai, Songyuan

2014-03-11

202

Micro–meso hierarchical porous carbon as low-cost counter electrode for dye-sensitized solar cells  

Microsoft Academic Search

A micro–meso hierarchical porous carbon with low crystallinity was prepared by a combination of self-assembly and post activation and explored as a counter electrode in dye-sensitized solar cells. Pore structure analysis showed that the pristine mesopores were basically preserved during activation and the micropores were mainly generated within the mesopore wall. Due to its low crystallinity and unique pore-structure including

Guiqiang Wang; Congcong Huang; Wei Xing; Shuping Zhuo

2011-01-01

203

Preparation and characterization of polyaniline film on stainless steel by electrochemical polymerization as a counter electrode of DSSC  

Microsoft Academic Search

Polyaniline (PANI) films were electrodeposited on stainless steel 304 (SS) from 0.5M H2SO4 solution containing 0.3M aniline by potentiostatic techniques to prepare a low cost and non-fragile counter electrode in dye-sensitized solar cell (DSSC). The compact layer, micro-particles, nanorods and fibrils were observed on the top of PANI films with different applied potentials (Eappl) by SEM. Then the conductivity and

Qi Qin; Jie Tao; Yan Yang

2010-01-01

204

Preliminary study on zinc–air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction  

Microsoft Academic Search

A zinc–air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction is reported in this paper. It possesses functions of both zincate reduction and electrochemical preparation, showing the potential for increasing the electronic energy utilization. Charge\\/discharge tests and scanning electron microscopy (SEM) micrographs reveal that when a nickel sheet plated with the high-H2-overpotential metal, cadmium, was

Yue-Hua Wen; Jie Cheng; Shang-Qi Ning; Yu-Sheng Yang

2009-01-01

205

Wurtzite copper-zinc-tin sulfide as a superior counter electrode material for dye-sensitized solar cells.  

PubMed

Wurtzite and kesterite Cu2ZnSnS4 (CZTS) nanocrystals were employed as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). Compared to kesterite CZTS, the wurtzite CZTS exhibited higher electrocatalytic activity for catalyzing reduction of iodide electrolyte and better conductivity. Accordingly, the DSSC with wurtzite CZTS CE generated higher power conversion efficiency (6.89%) than that of Pt (6.23%) and kesterite CZTS (4.89%) CEs. PMID:24191954

Kong, Jun; Zhou, Zheng-Ji; Li, Mei; Zhou, Wen-Hui; Yuan, Sheng-Jie; Yao, Rong-Yue; Zhao, Yang; Wu, Si-Xin

2013-01-01

206

Wurtzite copper-zinc-tin sulfide as a superior counter electrode material for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Wurtzite and kesterite Cu2ZnSnS4 (CZTS) nanocrystals were employed as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). Compared to kesterite CZTS, the wurtzite CZTS exhibited higher electrocatalytic activity for catalyzing reduction of iodide electrolyte and better conductivity. Accordingly, the DSSC with wurtzite CZTS CE generated higher power conversion efficiency (6.89%) than that of Pt (6.23%) and kesterite CZTS (4.89%) CEs.

Kong, Jun; Zhou, Zheng-Ji; Li, Mei; Zhou, Wen-Hui; Yuan, Sheng-Jie; Yao, Rong-Yue; Zhao, Yang; Wu, Si-Xin

2013-11-01

207

A red-to-gray poly(3-methylthiophene) electrochromic device using a zinc hexacyanoferrate\\/PEDOT:PSS composite counter electrode  

Microsoft Academic Search

In this paper, we describe a novel red-to-gray poly(3-methylthiophene) (PMeT) electrochromic device (ECD) with the aid of a zinc hexacyanoferrate (ZnHCF)\\/PEDOT:PSS counter electrode. The application of ZnHCF to an ECD is first reported. ZnHCF has long suffered from poor deposition yield problem, but we demonstrate that a robust ZnHCF film can be prepared by spin coating of a liquid suspension

Siang-Fu Hong; Lin-Chi Chen

2010-01-01

208

Fabrication of optically transparent carbon electrodes by the pyrolysis of photoresist films: approach to single-molecule spectroelectrochemistry.  

PubMed

This paper describes the preparation, physical and chemical characterization, and performance of carbon-based optically transparent electrodes (C-OTEs) fabricated by the pyrolysis of thin films of photoresist. The electrodes are prepared by spin coating dilute solutions of the positive photoresist AZ 4330 onto quartz substrates. Pyrolysis of these samples at 1000 degrees C in a reducing atmosphere yields optically transparent carbon films that have thicknesses ranging between 10 and 80 nm. Sheet resistance measurements, X-ray photoelectron spectroscopy, Raman spectroscopy, and atomic force microscopy were used to determine the physical and chemical properties of the films, and cyclic voltammetry and chronoabsorptometry were employed to delineate the electrochemical and conventional spectroelectrochemical performance of the C-OTEs. These findings showed that the transparency of this material improves as film thickness decreases, but at the expense of an increase in film resistance. At a wavelength of 500 nm, for example, 13- and 79-nm-thick films have transparencies of 47 and 10% and sheet resistances of 1100 and 210 Omega/ square, respectively. Importantly, adjusting the dilution factor allows the facile and reproducible variation of thickness and transparency. Preliminary results using these C-OTEs for single-molecule spectroelectrochemistry, which represents a new development in the merger of optical and electrochemical techniques, by probing the potential dependence of the adsorption of individual YOYO-I-labeled lambda-DNA are also presented. PMID:16615798

Donner, Sebastian; Li, Hung-Wing; Yeung, Edward S; Porter, Marc D

2006-04-15

209

Preparation of flexible organic solar cells with highly conductive and transparent metal-oxide multilayer electrodes based on silver oxide.  

PubMed

We report that significantly more transparent yet comparably conductive AgOx films, when compared to Ag films, are synthesized by the inclusion of a remarkably small amount of oxygen (i.e., 2 or 3 atom %) in thin Ag films. An 8 nm thick AgOx (O/Ag=2.4 atom %) film embedded between 30 nm thick ITO films (ITO/AgOx/ITO) achieves a transmittance improvement of 30% when compared to a conventional ITO/Ag/ITO electrode with the same configuration by retaining the sheet resistance in the range of 10-20 ? sq(-1). The high transmittance provides an excellent opportunity to improve the power-conversion efficiency of organic solar cells (OSCs) by successfully matching the transmittance spectral range of the electrode to the optimal absorption region of low band gap photoactive polymers, which is highly limited in OSCs utilizing conventional ITO/Ag/ITO electrodes. An improvement of the power-conversion efficiency from 4.72 to 5.88% is achieved from highly flexible organic solar cells (OSCs) fabricated on poly(ethylene terephthalate) polymer substrates by replacing the conventional ITO/Ag/ITO electrode with the ITO/AgOx/ITO electrode. This novel transparent electrode can facilitate a cost-effective, high-throughput, room-temperature fabrication solution for producing large-area flexible OSCs on heat-sensitive polymer substrates with excellent power-conversion efficiencies. PMID:24060352

Yun, Jungheum; Wang, Wei; Bae, Tae Sung; Park, Yeon Hyun; Kang, Yong-Cheol; Kim, Dong-Ho; Lee, Sunghun; Lee, Gun-Hwan; Song, Myungkwan; Kang, Jae-Wook

2013-10-23

210

Long-wavelength metal-semiconductor-metal photodetectors with transparent and opaque electrodes  

NASA Astrophysics Data System (ADS)

In this paper, we present a comparative study of transparent and opaque electrode InAlAs/InGaAs metal-semiconductor-metal photodiodes (MSMPDs) for operation at 1.31 and 1.55 micrometers . The transparent materials are indium-tin-oxide (ITO) and cadmium-tin-oxide (CTO) and the opaque material is Ti-Au. The rf magnetron sputtered films of ITO and CTO, deposited at a substrate temperature of 300 degrees C, exhibited as-deposited resistivities of 5.6(DOT)10-3 (Omega) (DOT)cm and 1.0(DOT)10-3 (Omega) (DOT)cm, respectively. The resistivity of the ITO and CTO films dropped to 1.1(DOT)10-3 (Omega) (DOT)cm and 5.2(DOT)10-4 (Omega) (DOT)cm, respectively, after a 4 minute 400 degree C anneal in an N2 ambient. The interdigitated ITO and CTO electrodes were made by etching in a methane:hydrogen (1 to 3) plasma. The responsivity of 1 micrometers finger by 1 micrometers spacing (1 by 1 micrometers ), 50 X 50 micrometers 2 active area, MSMPDs was 0.40 A/W for the Ti-Au, 0.66 A/W for the CTO, and 0.69 A/W for the ITO MSMPDs. The Ti-Au, CTO and ITO MSMPDs had 3- dB cut-off frequencies of 14.0 GHz, 7.5 GHz, and 5.0 GHz, respectively, from time-domain measurements performed at 1.3 micrometers and 11.26 GHz, 4.00 GHz, and 2.61 GHz, respectively, from frequency-domain measurements performed at 1.55 micrometers . Discrepencies between the 3-dB cut-off frequency obtained from the time-domain and the frequency-domain measurements are attributed to the time-domain measurement system's inability to accurately resolve low frequency behavior (below 2 GHz) and space charge effects.

Wohlmuth, Walter A.; Adesida, Ilesanmi; Caneau, Catherine

1995-09-01

211

All-metal-electrode-type dye sensitized solar cells (transparent conductive oxide-less dye sensitized solar cell) consisting of thick and porous Ti electrode with straight pores  

Microsoft Academic Search

Transparent conductive oxide (TCO) layer-less dye sensitized solar cells (DSCs) are reported. The cell is composed of a glass substrate, TiO2 porous layer stained with dye molecules, porous Ti electrode, electrolyte, and a Pt sputtered Ti sheet. The cell exhibits an efficiency of 7.43% which was a little less than that of 8.44% for a DSC consisting of a TCO

Yohei Kashiwa; Yorikazu Yoshida; Shuzi Hayase

2008-01-01

212

Modification of carbon nanotube transparent conducting films for electrodes in organic light-emitting diodes.  

PubMed

Single-walled carbon nanotube (SWCNT) transparent conducting films (TCFs) were fabricated for the electrodes of organic light-emitting diodes (OLEDs); three types of film were studied. The as-prepared SWCNT TCFs displayed a relatively low sheet resistance of 82.6 ?/sq at 80.7 T% with a relatively large surface roughness of 30 nm. The TCFs were top-coated with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) to obtain PEDOT:PSS-coated TCFs. The PEDOT:PSS cover improved the conductivity and decreased the surface roughness to 12 nm at the cost of film transmittance. The SWCNT TCFs mixed with PEDOT:PSS (PM-TCFs) exhibited a high conductivity (70.6 ?/sq at 81 T%) and a low surface roughness (3 nm) and were thus selected as the best TCFs for OLEDs. Blue flexible OLEDs with 4,4'-bis(2,2'-diphenylvinyl)-1,1'-biphenyl (Dpvbi) as the emitting layer were fabricated on TCFs with the same structures to evaluate the performances of the different types of SWCNT films for use in OLEDs. Of these three types of OLEDs, the PM-TCF devices exhibited the optimal performance with a maximum luminance of 2587 cd m(-2) and a current efficiency of 5.44 cd A(-1). This result was explored using field-emission scanning electron microscopy and atomic force microscopy to further study the mechanisms that are involved in applying SWCNT TCFs to OLEDs. PMID:24084604

Gao, Jing; Mu, Xue; Li, Xiao-Yun; Wang, Wen-Yi; Meng, Yan; Xu, Xiao-Bing; Chen, Li-Ting; Cui, Li-Jun; Wu, Xiaoming; Geng, Hong-Zhang

2013-11-01

213

Ultrathin polymer films for transparent electrode applications prepared by controlled nucleation.  

PubMed

The vacuum vapor phase polymerization (VPP) technique is capable of producing conducting polymer films with conductivities up to 3400 S cm(-1). However, the method is not able to produce robust nano-thin films as required for transparent conducting electrode (TCE) applications. We show that with the addition of aprotic solvents or chelating agents to the oxidant mixture, it is possible to control the polymerization rate, and nucleation, in the VPP process. This provides the opportunity of altering the grain size and depositing conducting polymer films with a thickness of 16 to 200 nm with resulting optical transmission within the range 50-98% that are robust enough to endure the post polymerization processing steps. The figure of merit (FoM), which is used to quantify a film's suitability for TCE applications, results in values from 12 to 25. This result indicates that the nano-films outperform most of the previously reported graphene films and approaches the accepted industry standard for TCE applications. PMID:24152113

Hojati-Talemi, Pejman; Bächler, Curdin; Fabretto, Manrico; Murphy, Peter; Evans, Drew

2013-11-27

214

Modification of carbon nanotube transparent conducting films for electrodes in organic light-emitting diodes  

NASA Astrophysics Data System (ADS)

Single-walled carbon nanotube (SWCNT) transparent conducting films (TCFs) were fabricated for the electrodes of organic light-emitting diodes (OLEDs); three types of film were studied. The as-prepared SWCNT TCFs displayed a relatively low sheet resistance of 82.6 ?/sq at 80.7 T% with a relatively large surface roughness of 30 nm. The TCFs were top-coated with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) to obtain PEDOT:PSS-coated TCFs. The PEDOT:PSS cover improved the conductivity and decreased the surface roughness to 12 nm at the cost of film transmittance. The SWCNT TCFs mixed with PEDOT:PSS (PM-TCFs) exhibited a high conductivity (70.6 ?/sq at 81 T%) and a low surface roughness (3 nm) and were thus selected as the best TCFs for OLEDs. Blue flexible OLEDs with 4,4?-bis(2,2?-diphenylvinyl)-1,1?-biphenyl (Dpvbi) as the emitting layer were fabricated on TCFs with the same structures to evaluate the performances of the different types of SWCNT films for use in OLEDs. Of these three types of OLEDs, the PM-TCF devices exhibited the optimal performance with a maximum luminance of 2587 cd m-2 and a current efficiency of 5.44 cd A-1. This result was explored using field-emission scanning electron microscopy and atomic force microscopy to further study the mechanisms that are involved in applying SWCNT TCFs to OLEDs.

Gao, Jing; Mu, Xue; Li, Xiao-Yun; Wang, Wen-Yi; Meng, Yan; Xu, Xiao-Bing; Chen, Li-Ting; Cui, Li-Jun; Wu, Xiaoming; Geng, Hong-Zhang

2013-11-01

215

Application of Single Wall Carbon Nanotubes as Transparent Electrodes in Cu(In,Ga)Se2-Based Solar Cells: Preprint  

SciTech Connect

We present a new thin-film solar cell structure in which the traditional transparent conductive oxide electrode (ZnO) is replaced by a transparent conductive coating consisting of a network of bundled single-wall carbon nanotubes. Optical transmission properties of these coatings are presented in relation to their electrical properties (sheet resistance), along with preliminary solar cell results from devices made using CuIn1-xGaxSe2 thin-film absorber materials. Achieving an energy conversion efficiency of >12% and a quantum efficiency of {approx}80% demonstrate the feasibility of the concept. A discussion of the device structures will be presented considering the physical properties of the new electrodes comparing current-voltage results from the new solar cell structure and those from standard ZnO/CdS/Cu(In,Ga)Se2/Mo solar cells.

Contreras, M.; Barnes, T.; van de Lagemaat, J.; Rumbles, G.; Coutts, T. J.; Weeks, C.; Glatkowski, P.; Levitsky, I.; Peltola, J.

2006-05-01

216

Impedance analysis of nanocarbon DSSC electrodes  

Microsoft Academic Search

Carbon nanoparticles and multiwall carbon nanotubes were deposited on an Optically Transparent Electrode (OTE) for application in Dye Sensitised Solar Cells (DSSCs) as counter electrode materials. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate the behaviour in a I3?\\/I? electrolyte solution. Results were compared to commercial Pt catalysed OTE and polycrystalline graphite. Multiwalled carbon nanotubes show low series resistance and

S. Gagliardi; L. Giorgi; R. Giorgi; N. Lisi; Th. Dikonimos Makris; E. Salernitano; A. Rufoloni

2009-01-01

217

A comparative study of the electrochemical behavior of complementary polymer electrochromic devices based on different counter-electrodes  

NASA Astrophysics Data System (ADS)

8,11-di-(4-thiophen-2-yl)acenaphtho[1,2-b]quinoxaline (DTAQ) was successfully synthesized via a Stille coupling reaction and the corresponding polymer (PDTAQ) was prepared electrochemically. The spectroelectrochemical and electrochromic properties of the polymer film reveal that PDTAQ film shows distinct color states (purple in the neutral state and blue in the oxidized state), and optical contrast (?T%) of 45.16% at 772 nm and 49.39% at 1100 nm with switching times of 2.5 and 0.5 s. Complementary electrochromic devices, which are based on the PDTAQ film as the working electrode, Prussian blue (PB) and V2O5 as counter-electrodes, respectively, and LiClO4/PC solution as the electrolyte, were assembled and characterized. The results illustrate that the properties of the PDTAQ/PB and PDTAQ/V2O5 devices (including the absorption, color changes, ?T% and response times) can be modified by the counter-electrodes. Furthermore, the PDTAQ/V2O5 device exhibits a significantly higher contrast ratio in the visible region (34.92% at 771 nm) and much faster response time (0.4 s) than the PDTAQ/PB device (21.32% at 552 nm).

Du, Qing; Mi, Sai; Zheng, Jianming; Xu, Chunye

2013-12-01

218

Optimization of Transparent Electrode for Solar Cell and Chemical Vapor Deposition of Amorphous Silicon. Final Technical Report, 15 September 1980-30 March 1983.  

National Technical Information Service (NTIS)

A film of fluorine-doped tin oxide can meet all these requirements. A new process for depositing fluorine-doped tin oxide films was optimized. Further optimization of the transparent electrode films has been accomplished, with increasing substrate tempera...

R. G. Gordon J. Proscia F. Ellis S. Kurtz

1983-01-01

219

Large-area transparent conductive few-layer graphene electrode in GaN-based ultra-violet light-emitting diodes  

NASA Astrophysics Data System (ADS)

We report on the development of a large-area few-layer graphene (FLG)--based transparent conductive electrode as a current spreading layer for GaN-based ultraviolet (UV) light-emitting diodes (LEDs). Large-area FLG was deposited on Cu using the chemical vapor deposition (CVD) method and subsequently transferred to the surface of the UV LED. UV light at a peak of 372 nm was emitted through the FLG-based transparent conductive electrode. The current spreading effects of FLG were clearly evident in both the optical images of electroluminescence (EL) and current-voltage (I-V) characteristics. Degradation of the FLG-based transparent conductive electrode could be induced by high power operation. Our results indicate that a large-area FLG-based electrode on GaN offers excellent current spreading and ultra-violet transparency properties when compared to the standard optoelectronic indium tin oxide (ITO) contact layer.

Kim, Byung-Jae; Lee, Chongmin; Jung, Younghun; Hyeon Baik, Kwang; Mastro, Michael A.; Hite, Jennifer K.; Eddy, Charles R.; Kim, Jihyun

2011-10-01

220

Graphene network on indium tin oxide nanodot nodes for transparent and current spreading electrode in InGaN/GaN light emitting diode  

NASA Astrophysics Data System (ADS)

We report a device that combines indium tin oxide (ITO) nanodot nodes with two-dimensional chemically converted graphene (CCG) films to yield a GaN-based light emitting diode (LED) with interesting characteristics for transparent and current spreading electrodes for the potential use in the ultraviolet region. The current-voltage characteristics and electroluminescence output power performance showed that CCG network on ITO nanodot nodes operated as a transparent and current spreading electrode in LED devices.

Seo, Tae Hoon; Lee, Kang Jea; Oh, Tae Su; Lee, Yong Seok; Jeong, Hyun; Park, Ah Hyun; Kim, Hun; Choi, Young Ran; Suh, Eun-Kyung; Cuong, Tran Viet; Pham, Viet Hung; Chung, Jin Suk; Kim, Eui Jung

2011-06-01

221

All-solid-state reflectance-type electrochromic devices using iridium tin oxide film as counter electrode  

Microsoft Academic Search

We prepared an all-solid-state reflectance-type electrochromic device (ECD), consisting of the following five layers: Al\\/WO3\\/Ta2O5\\/IrxSn1?xO2\\/ITO. Using RF ion plating, we prepared a film containing dispersed iridium oxide in a tin oxide matrix; this film acts as the counter electrode in the all-solid-state ECD. Protons were used as coloration ions in the ECD. The size of the ECD was 150cm2, and

Tatsuo Niwa; Osamu Takai

2010-01-01

222

Evaluation of surface control and durability CNT and ITO coated PET transparent electrode under different dry conditions  

NASA Astrophysics Data System (ADS)

Transparent electrodes using carbon nanotube (CNT) have recently been studied as potential replacements for convention ITO. In this work, CNT or ITO coated polyethylene terephthalate (PET) samples were prepared and studied. The degree of cohesion is dependent on the drying conditions. To explore effects of changing surface conditions, three drying temperatures, 20 °C, 80 °C, and 120 °C, were used. Electrical resistance measures were used to evaluate the interfacial durability and electrical properties of prepared transparent electrodes. FE-SEM was used to investigate surface changes and UV-spectroscopy was used to evaluate transparency as functions of the different drying temperatures. The electronic properties for these nanoparticle coated surfaces were evaluated using a cyclic voltametry method. Interfacial durability was evaluated by static contact angle measurement changes with elapsed time. The pH values of the coatings were measured in a water solution. The durability of the CNT coated surfaces was found to be better than that of the ITO coated surfaces. The higher drying temperatures were found to produce better surfaces because of improved cohesion between the nanoparticles which resulted in improved electrical properties and improved durability of the coated surfaces.

Park, Joung-Man; Kwon, Dong-Jun; Wang, Zuo-Jia; Gu, Ga-Young; Devries, Lawrence

2012-02-01

223

Mechanical reliability of transparent conducting IZTO film electrodes for flexible panel displays  

Microsoft Academic Search

The mechanical reliability of transparent In–Zn–Sn–O (IZTO) films grown using pulsed DC magnetron sputtering with a single oxide alloyed ceramic target on a transparent polyimide (PI) substrate at room temperature is investigated. All IZTO films deposited at room temperature have an amorphous structure. However, their optical and electrical properties change depending on the oxygen partial pressure applied during depositing process.

Young Sung Kim; Woo Jin Hwang; Kyung Tae Eun; Sung-Hoon Choa

2011-01-01

224

In-situ electrochemically deposited polypyrrole nanoparticles incorporated reduced graphene oxide as an efficient counter electrode for platinum-free dye-sensitized solar cells.  

PubMed

This paper reports a rapid and in-situ electrochemical polymerization method for the fabrication of polypyrrole nanoparticles incorporated reduced graphene oxide (rGO@PPy) nanocomposites on a ITO conducting glass and its application as a counter electrode for platinum-free dye-sensitized solar cell (DSSC). The scanning electron microscopic images show the uniform distribution of PPy nanoparticles with diameter ranges between 20 and 30?nm on the rGO sheets. The electrochemical studies reveal that the rGO@PPy has smaller charge transfer resistance and similar electrocatalytic activity as that of the standard Pt counter electrode for the I3(-)/I(-) redox reaction. The overall solar to electrical energy conversion efficiency of the DSSC with the rGO@PPy counter electrode is 2.21%, which is merely equal to the efficiency of DSSC with sputtered Pt counter electrode (2.19%). The excellent photovoltaic performance, rapid and simple fabrication method and low-cost of the rGO@PPy can be potentially exploited as a alternative counter electrode to the expensive Pt in DSSCs. PMID:24930387

Lim, Su Pei; Pandikumar, Alagarsamy; Lim, Yee Seng; Huang, Nay Ming; Lim, Hong Ngee

2014-01-01

225

In-situ electrochemically deposited polypyrrole nanoparticles incorporated reduced graphene oxide as an efficient counter electrode for platinum-free dye-sensitized solar cells  

PubMed Central

This paper reports a rapid and in-situ electrochemical polymerization method for the fabrication of polypyrrole nanoparticles incorporated reduced graphene oxide (rGO@PPy) nanocomposites on a ITO conducting glass and its application as a counter electrode for platinum-free dye-sensitized solar cell (DSSC). The scanning electron microscopic images show the uniform distribution of PPy nanoparticles with diameter ranges between 20 and 30?nm on the rGO sheets. The electrochemical studies reveal that the rGO@PPy has smaller charge transfer resistance and similar electrocatalytic activity as that of the standard Pt counter electrode for the I3?/I? redox reaction. The overall solar to electrical energy conversion efficiency of the DSSC with the rGO@PPy counter electrode is 2.21%, which is merely equal to the efficiency of DSSC with sputtered Pt counter electrode (2.19%). The excellent photovoltaic performance, rapid and simple fabrication method and low-cost of the rGO@PPy can be potentially exploited as a alternative counter electrode to the expensive Pt in DSSCs.

Lim, Su Pei; Pandikumar, Alagarsamy; Lim, Yee Seng; Huang, Nay Ming; Lim, Hong Ngee

2014-01-01

226

Dye sensitized solar cell based on platinum decorated multiwall carbon nanotubes as catalytic layer on the counter electrode  

SciTech Connect

Graphical abstract: I-V characteristics of the DSSCs with Pt CE and Pt/MWCNT CE measured at 100 mW/cm{sup 2}. It shows relatively better performance with Pt/MWCNT counter electrodes. Highlights: {yields} Synthesis of multiwalled carbon nanotubes by pyrolysis. {yields} Synthesis of Pt/MWCNT composite by chemical reduction. {yields} Fabrication DSSC using Pt/MWCNT as catalytic layer on the counter electrode. {yields} Study of catalytic activity by Electrochemical Impedance Spectroscopy. -- Abstract: In this study we have employed multiwall carbon nanotubes (MWCNT), decorated with platinum as catalytic layer for the reduction of tri-iodide ions in dye sensitized solar cell (DSSC). MWCNTs have been prepared by a simple one step pyrolysis method using ferrocene as the catalyst and xylene as the carbon source. Platinum decorated MWCNTs have been prepared by chemical reduction method. The as prepared MWCNTs and Pt/MWCNTs have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In combination with a dye adsorbed TiO{sub 2} photoanode and an organic liquid electrolyte, Pt/MWCNT composite showed an enhanced short circuit current density of 16.12 mA/cm{sup 2} leading to a cell efficiency of 6.50% which is comparable to that of Platinum.

Mathew, Ambily [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 India (India)] [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 India (India); Rao, G. Mohan, E-mail: gmrao@isu.iisc.ernet.in [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 India (India); Munichandraiah, N. [Department of Inorgonic and Physical Chemistry, Indian Institute of Science, Bangalore 560012 India (India)] [Department of Inorgonic and Physical Chemistry, Indian Institute of Science, Bangalore 560012 India (India)

2011-11-15

227

Toward Low-Cost, High-Efficiency, and Scalable Organic Solar Cells with Transparent Metal Electrode and Improved Domain Morphology  

SciTech Connect

We review our recent progress toward realizing future low-cost, high-efficiency, and scalable organic solar cells (OSCs). First, we show that the transparent electrodes based on metallic nanostructure is a strong candidate as a replacement of conventional indium tin oxide (ITO) electrode due to their superior properties, such as high optical transparency, good electrical conductivity, and mechanical flexibility, and the versatility that these properties can be adjusted independently by changing the linewidth and thickness of the metal grid structure. Furthermore, we exploited the unique optical properties due to the excitation of surface plasmon resonance by the metallic nanogratings to enhance the light absorption of organic semiconductors, and demonstrated enhanced power conversion efficiency than devices made using ITO electrode. In addition, we also investigated a new device fabrication process with a focus on the photoactive layer formation, which produces the most optimum bulk-heterojunction morphology compared with conventional annealing-based methods. Finally, we successfully demonstrated that these approaches are scalable to large-area and high-speed roll-to-roll processes. We believe that the works highlighted in this paper represent one step forward to realizing low-cost, high-efficiency, and large-area OSCs.

Kang, Myung-Gyu; Park, Hui Joon; Ahn, Se Hyun; Xu, Ting; Guo, L. Jay

2010-01-01

228

Synthesis and characterization of natural dye and counter electrode thin films with different carbon materials for dye-sensitized solar cells.  

PubMed

This study aims to deal with the film of the counter electrode of dye-sensitized solar cells (DSSCs) and the preparation, structure and characteristics of the extract of natural dye. This study adopts different commercial carbon materials such as black lead, carbon black and self-made TiO2-MWCNT compound nanoparticle as the film of the counter electrodes. Moreover, for the preparation of natural dyes, anthocyanins and chlorophyll dyes are extracted from mulberry and pomegranate respectively. Furthermore, the extracted anthocyanins and chlorophyll are blended into cocktail dye to complete the preparation of natural dye. Results show that the photoelectric conversion efficiency of the single-layer TiO2-MWCNT counter electrode film and the cocktail dye of the DSSCs is 0.462%. PMID:22103229

Chang, Ho; Chen, Tien-Li; Kao, Mu-Jung; Chen, Chih-Hao; Chien, Shu-Hua; Jiang, Lii-Jenq

2011-08-01

229

Conductive Upconversion Er,Yb-FTO Nanoparticle Coating To Replace Pt as a Low-Cost and High-Performance Counter Electrode for Dye-Sensitized Solar Cells.  

PubMed

F-doped SnO2 (FTO) nanocrystals modified by Er and Yb with upconversion capability and excellent catalytic properties have been designed and fabricated as an economic replacement for Pt for use as the counter electrode (CE) in dye-sensitized solar cells. The cost of the UC-FTO counter electrode is only ?(1)/20th of that for Pt. The upconverted luminescence-mediated energy transfer and the superior catalytic property for I3(-)/I(-) circulation overpowered the slight degradation caused by increased CE/electrolyte interface resistance. A 23.9% enhancement in photocurrent was achieved with little degradation in photovoltage, resulting in a 9.12% increase in solar-to-electric power conversion efficiency. Near-infrared (NIR) light-to-electricity has been directly observed by SPS and IPCE characterizations, showing the effect of the upconversion counter electrode. PMID:24810204

Li, Liang; Yang, Yulin; Fan, Ruiqing; Chen, Shuo; Wang, Ping; Yang, Bin; Cao, Wenwu

2014-06-11

230

GaN nanorod light emitting diodes with suspended graphene transparent electrodes grown by rapid chemical vapor deposition  

SciTech Connect

Ordered and dense GaN light emitting nanorods are studied with polycrystalline graphene grown by rapid chemical vapor deposition as suspended transparent electrodes. As the substitute of indium tin oxide, the graphene avoids complex processing to fill up the gaps between nanorods and subsequent surface flattening and offers high conductivity to improve the carrier injection. The as-fabricated devices have 32% improvement in light output power compared to conventional planar GaN-graphene diodes. The suspended graphene remains electrically stable up to 300?°C in air. The graphene can be obtained at low cost and high efficiency, indicating its high potential in future applications.

Xu, Kun; Xu, Chen, E-mail: xuchen58@bjut.edu.cn; Deng, Jun; Zhu, Yanxu; Guo, Weiling; Mao, Mingming; Xun, Meng; Chen, Maoxing; Zheng, Lei [Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124 (China)] [Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124 (China); Xie, Yiyang [State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences, Beijing 100083 (China)] [State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences, Beijing 100083 (China); Sun, Jie, E-mail: jie.sun@chalmers.se [Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124 (China) [Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124 (China); Mikroteknologi och Nanovetenskap, Chalmers Tekniska Högskola AB, Göteborg 41296 (Sweden)

2013-11-25

231

GaN nanorod light emitting diodes with suspended graphene transparent electrodes grown by rapid chemical vapor deposition  

NASA Astrophysics Data System (ADS)

Ordered and dense GaN light emitting nanorods are studied with polycrystalline graphene grown by rapid chemical vapor deposition as suspended transparent electrodes. As the substitute of indium tin oxide, the graphene avoids complex processing to fill up the gaps between nanorods and subsequent surface flattening and offers high conductivity to improve the carrier injection. The as-fabricated devices have 32% improvement in light output power compared to conventional planar GaN-graphene diodes. The suspended graphene remains electrically stable up to 300 °C in air. The graphene can be obtained at low cost and high efficiency, indicating its high potential in future applications.

Xu, Kun; Xu, Chen; Xie, Yiyang; Deng, Jun; Zhu, Yanxu; Guo, Weiling; Mao, Mingming; Xun, Meng; Chen, Maoxing; Zheng, Lei; Sun, Jie

2013-11-01

232

Highly conductive, flexible and scalable graphene hybrid thin films with controlled domain size as transparent electrodes.  

PubMed

Highly conductive, transparent, flexible and scalable graphene hybrid thin films with controlled domain size were successfully fabricated via a mechanochemical method, screen printing and pressure-assisted reduction process. PMID:24825128

Shin, Keun-Young; Jang, Jyongsik

2014-05-27

233

Characterization of screen printed carbon counter electrodes for Co(II)\\/(III) mediated photoelectrochemical cells  

Microsoft Academic Search

A screen printed carbon electrode associated with Tris(4,4?-di-tert-butyl-2,2?-bipyridine)Cobalt(II) as redox mediator was investigated as possible alternative to the volatile and corrosive iodide\\/triodide system in dye sensitized solar cells (DSSCs). We report here a first study on the screen printing technology for the manufacturing of an advanced and stable carbon cathode for dye sensitized solar cell. The electrode surface was characterized

Fouad Ghamouss; Robbin Pitson; Fabrice Odobel; Mohammed Boujtita; Stefano Caramori; Carlo A. Bignozzi

2010-01-01

234

Synthesis of Cu2ZnSnS4 nanoparticles by solution based solid state reaction process and its application in dye sensitized solar cell as counter electrode  

NASA Astrophysics Data System (ADS)

Cu2ZnSnS4 (CZTS) nanoparticles were synthesized by using solution based solid state reaction process and films were coated on FTO (Fluorine doped tin oxide) substrate using doctor blade technique. Phase identification, crystallinity of the synthesized nanoparticles was confirmed by XRD and Raman spectroscopy. Dye sensitized solar cells (DSSC) fabricated with CZTS as counter electrode showed photo conversion efficiency 2.57 % compared to Pt based counter electrode 3.17 % efficiency. The charge transport at CZTS/ electrolyte interface was studied by using electrochemical impedance spectroscopy.

Mokurala, Krishnaiah; Bhargava, Parag; Mallick, Sudhanshu

2014-04-01

235

In situ grown vertically oriented CuInS2 nanosheets and their high catalytic activity as counter electrodes in dye-sensitized solar cells.  

PubMed

Vertically oriented CuInS(2) nanosheet thin films were prepared via a facile one-step solvothermal process and used in dye-sensitized solar cells (DSSCs) as counter electrodes. The catalytic activity of the CuInS(2) films based on different precursor concentrations was investigated using electrochemical methods. DSSCs based on optimized CuInS(2) thin film as counter electrodes reached a power conversion efficiency of 6.33%, comparable to that of sputtering Pt (6.07%). PMID:23388681

Yang, Jie; Bao, Chunxiong; Zhang, Jiyuan; Yu, Tao; Huang, Huan; Wei, Yulong; Gao, Hao; Fu, Gao; Liu, Jianguo; Zou, Zhigang

2013-03-11

236

Room temperature flexible and transparent ITO/Ag/ITO electrode grown on flexile PES substrate by continuous roll-to-roll sputtering for flexible organic photovoltaics  

NASA Astrophysics Data System (ADS)

We prepared a flexible and transparent indium tin oxide (ITO)/Ag/ITO electrode on a polyethersulfone (PES) substrate using a specially designed roll-to-roll sputtering system at room temperature for use in flexible organic solar cells (OSCs). By the continuous roll-to-roll sputtering of the ITO and Ag targets, we fabricated a flexible ITO/Ag/ITO electrode with a sheet resistance (Rsh) of 4.28 ?/square, optical transmittance (T) of 89.28% and figure of merit value of 75.03 × 10-3 ?-1 at the optimized Ag thickness of 12 nm (dc power of 200 W) without breaking the vacuum, even though it was deposited at room temperature. The bending test results demonstrated that the ITO/Ag/ITO electrode has superior flexibility to the single ITO electrode, due to the high failure strain of the ductile Ag layer. Moreover, the flexible OSC fabricated on the optimized flexible ITO/Ag/ITO electrode showed an identical efficiency of 3.73% to the OSC fabricated on the commercial crystalline ITO electrode, due to its low sheet resistance and high transparency, which are well matched with the organic active layer. This indicates that the flexible ITO/Ag/ITO multilayer electrode grown by the continuous roll-to-roll sputtering technique is a promising flexible and transparent electrode for use in cost-efficient flexible OSCs.

Park, Yong-Seok; Choi, Kwang-Hyuk; Kim, Han-Ki

2009-12-01

237

ZnS/Ag/ZnS nano-multilayer films for transparent electrodes in flat display application  

NASA Astrophysics Data System (ADS)

In this paper, ZnS/Ag/ZnS nano-multilayers for transparent electrodes in flat display application have been prepared by thermal evaporation in vacuum. The sheet resistance of the films was low as 3 ?/cm 2. And they can be applied as good selective filters with the luminous transmittance Tlum about 90% and IR reflectance above 90%. The merit FTC for revaluing transparent electrodes reached 7.3×10 -2 ?-1 at 550 nm wavelength. Among the prepared films, some extreme asymmetrical structures having good performances were firstly reported. The influence of thickness of layers on the optic and electrical performance and thermal stability of multilayers was analyzed. Spectroscopic ellipsometry analysis indicated that the interlayers between Ag and ZnS layer contained a physical mixture layer and a compound semiconductor layer. After heat treatment, there existed a vulcanized Ag layer and the further diffusion and chemical combination between layers, which reduced the transmittance and the conductivity of the whole system.

Liu, Xuanjie; Cai, Xun; Mao, Jifang; Jin, Chengyu

2001-11-01

238

Design and fabrication of nanometric TiO2/Ag/TiO2/Ag/TiO2 transparent conductive electrode for inverted organic photovoltaic cells application  

NASA Astrophysics Data System (ADS)

In this study, transparent conductive TiO2/Ag/TiO2/Ag/TiO2 (TATAT) nano-multilayer system is designed and optimum thickness of TiO2 and Ag layers are calculated. TATAT nano-multilayer films were deposited on glass substrates at room temperature by a thermal evaporation technique. We investigated some electrical, optical and structural properties of optimized TATAT multilayer such as sheet resistance, optical transmittance and the root-mean-square surface roughness. Here, we suggest a very low resistance transparent electrode (2.3 (?/?)) with a high transmittance (90%) for optoelectronics applications. Inverted organic photovoltaic cell was fabricated on the TATAT cathode. The fabricated cell with 12 nm of Ag layer shows higher power conversion efficiency (2.68%) compared to that fabricated on the ITO electrode (1.84%). The results show that the TATAT multilayer system is a suitable structure for use as transparent conductive electrode in optoelectronic devices.

Ghasemi Varnamkhasti, Mohsen; Shahriari, Esmaeil

2014-05-01

239

Solution-Processable Transparent Conductive Hole Injection Electrode for OLED SSL.  

National Technical Information Service (NTIS)

An interconnected network of silver nanowires has been used as transparent anode in OLED devices. This layer was deposited by spin-coating and slot-die coating from an aqueous nanowire suspension. The sheet resistance of the film was 10 ohms/sq with a tra...

F. Pschenitzka M. Mathai T. Torke

2012-01-01

240

Large-scale patterned multi-layer graphene films as transparent conducting electrodes for GaN light-emitting diodes  

Microsoft Academic Search

This work demonstrates a large-scale batch fabrication of GaN light-emitting diodes (LEDs) with patterned multi-layer graphene (MLG) as transparent conducting electrodes. MLG films were synthesized using a chemical vapor deposition (CVD) technique on nickel films and showed typical CVD-synthesized MLG film properties, possessing a sheet resistance of {\\\\sim }620~\\\\Omega \\/\\\\square with a transparency of more than 85% in the 400-800

Gunho Jo; Minhyeok Choe; Chu-Young Cho; Jin Ho Kim; Woojin Park; Sangchul Lee; Woong-Ki Hong; Tae-Wook Kim; Seong-Ju Park; Byung Hee Hong; Yung Ho Kahng; Takhee Lee

2010-01-01

241

Improving temperature-stable AZO-Ag-AZO multilayer transparent electrodes using thin Al layer modification  

NASA Astrophysics Data System (ADS)

The thermal stability of AZO/Al/Ag/Al/AZO (5A) compared with AZO/Ag/AZO (3A) electrodes was significantly improved by introducing a thin Al layer at the interface between Ag and AZO layers. The rapidly deteriorated sheet resistance of 3A compared with 5A electrodes is roughly consistent with the XRD results of weaker intensity of the (1?1?1) Ag peak of 3A after annealing for 20 h at 300 or 500 °C for 10 min. The improved thermal stability of the 5A electrode is ascribed to the limitation function of Al atoms on Ag diffusion into the AZO layer. The polymer solar cells based on 5A compared with ITO electrodes showed a similar efficiency.

Zhou, Lin; Chen, Xiaohong; Zhu, Feng; Sun, XinXing; Sun, Zhuo

2012-12-01

242

Layer-by-layer self-assembled mesoporous PEDOT-PSS and carbon black hybrid films for platinum free dye-sensitized-solar-cell counter electrodes  

NASA Astrophysics Data System (ADS)

A thin film of poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonic acid) (PEDOT-PSS), which is an alternative cathodic catalyst for Pt in dye-sensitized solar cells, was prepared using the layer-by-layer self-assembly method (LbL). The film is highly adhesive to the substrate and has a controllable thickness. Therefore, the PEDOT-PSS film prepared using LbL is expected have high performance and durability as a counter electrode. Moreover, when carbon black was added to the PEDOT-PSS solution, highly mesoporous PEDOT-PSS and carbon black hybrid films were obtained. These films showed high cathodic activity. In this study, we investigated the change in morphology in the obtained film with increasing carbon black content, and the influence of the porosity and thickness on the performance of the cells. In this study, a Pt-free counter electrode with performance similar to that of Pt-based counter electrodes was successfully fabricated. The achieved efficiency of 4.71% was only a factor of 8% lower than that of the cell using conventional thermally deposited Pt on fluorine-doped tin oxide glass counter electrodes.

Kitamura, Koji; Shiratori, Seimei

2011-05-01

243

Electrodeposition of CoS on ITO substrates for the counter electrode of dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Dye-sensitized solar cells (DSSCs) provide a relatively low-cost option for harvesting solar energy. The counter electrode (CE) of a DSSC incorporates a catalyst layer, which plays a vital role in the cell cycle by reducing the triiodide ions in the electrolyte. In this study, CoS is studied as a possible replacement for platinum, the standard catalyst [1]. This is relevant because replacing Pt with CoS would reduce production barriers that are associated with cost and supply. Using a two-electrode ``dummy'' flow cell setup the effects of delay times, scan rates and bias voltages in electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements were studied. Preliminary results on CoS samples are taken and indicate charge transfer resistance values an order of magnitude higher than the Pt reference. Future steps to improve the CoS deposition process to optimize charge transfer will be discussed.[4pt] [1] Wang, M.; Anghel, A.M.; Marsan, B.; Ha, N.C.; Pootrakulchote, N.; Zakeeruddin, S.M.; Graetzel, M. J. Am. Chem. Soc. 2009, 131, 15976.

Masuda, Tamiko; Anwar, Hafeez; Hill, Ian

2012-10-01

244

Rapid thermal annealed WO3-doped In2O3 films for transparent electrodes in organic photovoltaics  

NASA Astrophysics Data System (ADS)

We investigated the effect of rapid thermal annealing (RTA) on the electrical, optical, structural and surface properties of WO3-doped In2O3 (IWO) films for use in organic solar cells (OSCs). Increasing the RTA temperature led to significant decreases in resistivity and sheet resistance due to activation of the W dopants and the (2?2?2) preferred orientation of the IWO films. At the optimized RTA temperature of 500 °C, the IWO film had a sheet resistance of 21 ?/square and an optical transmittance of 89.39%, which is comparable to conventional ITO electrodes. Due to the high mobility of 46 cm2 V-1 s-1, the IWO film showed a higher optical transmittance in the near infrared wavelength region even though it had a low resistivity of 4.34 × 10-4 ? cm. Furthermore, the 500 °C annealed IWO film showed very smooth surface morphology due to its (2?2?2) preferred orientation. The performance (fill factor of 61.59%, short circuit current of 8.84 mA cm-2, open circuit voltage of 0.60 V and power conversion efficiency of 3.27%) of the OSC fabricated with the IWO electrode was nearly identical to that of the OSC with a reference ITO anode, indicating that the IWO anode is a promising high-mobility transparent electrode material to replace conventional ITO anodes for high-performance OSCs.

Kim, Jun Ho; Shin, Yong-Hee; Seong, Tae-Yeon; Na, Seok-In; Kim, Han-Ki

2012-10-01

245

Roll-to-roll production of 30-inch graphene films for transparent electrodes  

Microsoft Academic Search

The outstanding electrical1, mechanical and chemical properties of graphene make it attractive for applications in flexible electronics. However, efforts to make transparent conducting films from graphene have been hampered by the lack of efficient methods for the synthesis, transfer and doping of graphene at the scale and quality required for applications. Here, we report the roll-to-roll production and wet-chemical doping

Byung Hee Hong

2011-01-01

246

Electronic and structural properties of graphene-based transparent and conductive thin film electrodes  

Microsoft Academic Search

We demonstrate that graphene-based transparent and conductive thin films (GTCFs), fabricated by thermal reduction of graphite\\u000a oxide, have very similar electronic and structural properties as highly oriented pyrolytic graphite (HOPG). Electron spectroscopy\\u000a results suggest that the GTCFs are also semi-metallic and that the individual graphene sheets of the film are predominantly\\u000a oriented parallel to the substrate plane. These films may

A. Vollmer; X. L. Feng; X. Wang; L. J. Zhi; K. Müllen; N. Koch; J. P. Rabe

2009-01-01

247

Synthesis of Ag nanowires for the fabrication of transparent conductive electrode.  

PubMed

Recently, advances in nano-materials research have opened the door for various transparent conductive materials, which include CNTs, graphene, Ag and Cu nanowires, and printable metal grids. Among them, Ag nanowires are particularly interesting to synthesize because bulk Ag exhibits the highest electrical conductivity among all metals. We tried to synthesize the Ag nanowires with a small diameter and long length, resulting in large aspect ratios. For the synthesis of the Ag nanowires, effects of various experimental parameters, i.e., the reaction time for synthesis, molar ratio of Ag source to surfactant, and molar weight of the surfactant were investigated with the physical shape of synthesized products. The Ag nanowire suspensions were formulated with the synthesized Ag nanowires, and a bar coating method with a Meyer rod was used to fabricate the transparent and conductive film on a glass substrate. For the thinnest wet coating, the transparent conductive layer of 90.6% transmittance at 550 nm of light wavelength and 66 ohm/sq sheet resistance could be obtained, while 13 ohm/sq was achieved at the transmittance of 76%. PMID:24205638

Kim, Jong-Woong; Lee, Sung-Won; Lee, Yeji; Jung, Seung-Boo; Hong, Sung-Jei; Kwak, Min-Gi

2013-09-01

248

A facile and rapid process to fabricate platinum counter electrode in dye-sensitized solar cell using nanosecond pulsed laser sintering at room temperature.  

PubMed

To fabricate the platinum (Pt) counter electrode in dye-sensitized solar cells (DSSCs), rapid and low sintering process was carried out using nanosecond pulsed laser sintering (LS) method based on third harmonic (355 nm) of an Nd:YAG laser at room temperature. The surface morphology of LS-Pt on fluorine-doped tin oxide (FTO) electrode showed thin and compact structure, consisting of particles size of - 10-30 nm and thickness of below 30 nm. The DSSCs with the LS-Pt/FTO counter electrodes displayed the power conversion efficiency of 4.4% with short-circuit current = 9.07 mA/cm2, open-circuit voltage = 0.79 V and fill factor = 61.3. PMID:24758023

Kang, Tae Yeon; Yoo, Kicheon; Lee, Jin Ah; Lee, Wonjoo; Kim, Kyungkon; Lee, Doh-Kwon; Kim, Honggon; Ko, Min Jae

2014-07-01

249

Light energy conversion with chlorophyll a and pheophytin a monolayers at the optically transparent SnO 2 electrode: artificial photosynthesis  

Microsoft Academic Search

The photoelectrochemical behavior of chlorophyll a and pheophytin a monolayers, deposited on tin oxide (SnO2) optically transparent electrodes (OTE) by means of the Langmuir-Blodgett technique, has been investigated. The photocurrent action spectra coincide with the absorption spectra of photosynthetic pigment monolayers at the SnO2\\/solution interfaces. Anodic and cathodic photocurrents were measured at various electrode potentials. Effects of electrolyte concentration, pH,

A. G. Volkov; M. I. Gugeshashvili; B. Zelent; D. Côte; G. Munger; A. Tessier; P.-F. Blanchet; R. M. Leblanc

1995-01-01

250

Amorphous Nb/Fe-oxide ion-storage films for counter electrode applications in electrochromic devices  

SciTech Connect

The electrochromic properties of mixed Nb/Fe-oxide films with amorphous structure which were prepared via the sol-gel route were determined. Films with Nb/Fe molar concentration ratios 0.2:1, 0.4:1, and 1:1 exhibit ion-storage capacities up to 18 mC/cm{sup 2} depending on Nb/Fe molar ratio. Electrochromically films behave as optically passive electrodes with a coloration efficiency of nearly zero at {lambda} > 480 nm, while at shorter wavelengths a relatively strong anodic coloring was observed, yielding negative coloration efficiencies up to {minus}20 cm{sup 2}/C. Coloring/bleaching changes of films are correlated with the ex situ IR spectroscopic measurements of charged/discharged films showing distortions of the film structure with Li{sup +} ion insertion/extraction reactions. Electrochemical stability of Nb/Fe (0.4:1)-oxide films was tested up to 2,000 cycles in a sol-gel electrochromic device consisting of sol-gel-derived WO{sub 3} films and hybrid organic/inorganic ionic conductor with ionic conductivity of about 10{sup {minus}4} S/cm serving for lamination of the electrodes.

Orel, B.; Macek, M.; Lavrencic-Stangar, U. [National Inst. of Chemistry, Ljubljana (Slovenia); Pihlar, B. [Univ. of Ljubljana (Slovenia). Faculty of Chemistry

1998-05-01

251

Graphene transparent electrode for enhanced optical power and thermal stability in GaN light-emitting diodes  

NASA Astrophysics Data System (ADS)

We report an improvement of the optical power and thermal stability of GaN LEDs using a chemically doped graphene transparent conducting layer (TCL) and a low-resistance contact structure. In order to obtain low contact resistance between the TCL and p-GaN surface, a patterned graphene TCL with Cr/Au electrodes is suggested. A bi-layer patterning method of a graphene TCL was utilized to prevent the graphene from peeling off the p-GaN surface. To improve the work function and the sheet resistance of graphene, CVD (chemical vapor deposition) graphene was doped by a chemical treatment using a HNO3 solution. The effect of the contact resistance on the power degradation of LEDs at a high injection current level was investigated. In addition, the enhancement of the optical power via an increase in the current spreading and a decrease in the potential barrier of the graphene TCL was investigated.

Youn, Doo-Hyeb; Yu, Young-Jun; Choi, HongKyw; Kim, Suck-Hwan; Choi, Sung-Yool; Choi, Choon-Gi

2013-02-01

252

Graphene as tunable transparent electrode material on GaN: Layer-number-dependent optical and electrical properties  

NASA Astrophysics Data System (ADS)

Graphene has been regarded as a prospective transparent electrode for a GaN-based light-emitting diode (LED), but fundamental knowledge about the intrinsic properties of the graphene/GaN contact is lacking. We have studied the optical and electronic properties of graphene exfoliated on an n-type GaN surface. The graphene visibility was simulated based on Fresnel's law and confirmed with an optical microscope and micro-Raman spectra. The interfacial electronic property was studied with a scanning photoelectron microscope. We found that the Schottky barrier height of the graphene/n-GaN is decreased with decreasing graphene number of layers, yielding an improved GaN-based LED performance.

Shiu, Hung Wei; Yueh Chang, Lo; Lee, Kai-Hsuan; Chen, Hung-Ying; Gwo, Shangjr; Chen, Chia-Hao

2013-08-01

253

Optimization of transparent electrode for solar cells. Technical report, September 15, 1981March 15, 1982  

Microsoft Academic Search

A simple, sensitive, and reliable method for measuring the interfacial or contact resistance between tin oxide and silicon is reported. The method consists of depositing a doped tin oxide layer on a wafer of highly conductive single-crystal silicon. Metallic electrodes are applied to the surface of the tin oxide and to the opposite surface of the silicon. The coated and

1982-01-01

254

Silver nanowire network transparent electrodes with highly enhanced flexibility by welding for application in flexible organic light-emitting diodes.  

PubMed

We present highly flexible Ag nanowire (AgNW) networks welded with transparent conductive oxide (TCO) for use in electrical interconnects in flexible and wearable electronic devices. The hybrid transparent conductive electrodes (TCEs) produced on polymer substrates consist of AgNW networks and TCO that is deposited atop the AgNWs. The TCO firmly welds the AgNWs together at the junctions and the AgNWs to the polymer substrates. Transmission electron microscopy (TEM) analysis show that TCO atop and near AgNWs grows as crystalline because AgNWs act as crystalline seeds, but the crystallinity of the matrix TCO can be controlled by sputtering conditions. The sheet resistances (Rs) of hybrid TCEs are less than the AgNW networks because junction resistance is significantly reduced due to welding by TCO. The effect of welding on decreasing Rs is enhanced with increasing matrix crystallinity, as the adhesion between AgNWs and TCO is improved. Furthermore, the bending stability of the hybrid TCEs are almost equivalent to and better than AgNW networks in static and cyclic bending tests, respectively. Flexible organic light-emitting diodes (f-OLEDs) are successfully fabricated on the hybrid TCEs without top-coats and the performances of f-OLEDs on hybrid TCEs are almost equivalent to those on commercial TCO, which supports replacing indium tin oxide (ITO) with the hybrid TCEs in flexible electronics applications. PMID:24720620

Cheong, Hahn-Gil; Triambulo, Ross E; Lee, Gun-Hwan; Yi, In-Sook; Park, Jin-Woo

2014-05-28

255

Spin coated graphene films as the transparent electrode in organic photovoltaic devices  

Microsoft Academic Search

Many research efforts have been devoted to the replacement of the traditional indium–tin-oxide (ITO) electrode in organic photovoltaics. Solution-based graphene has been identified as a potential replacement, since it has less than two percent absorption per layer, relative high carrier mobility, and it offers the possibility of deposition on large area and flexible substrates, compatible with roll to roll manufacturing

E. Kymakis; E. Stratakis; M. M. Stylianakis; E. Koudoumas; C. Fotakis

256

Transparent conductive multiwall carbon nanotubes-polymer composite for electrode applications.  

PubMed

Disperse Multiwall carbon nanotubes (MWCNTs) are incorporated aqueous N-hydroxy methyl acrylamide, which is subjected to crosslinking to develop a transparent conductive composite free standing film. The effects of the concentration of MWCNTs and temperature on optical and electrical properties of nano-composites are investigated. Interestingly, only 0.06 mg/ml of MWCNTs is sufficient to reach the percolation threshold (Phi) for transition in electrical conductivity up to 10(-4) S/cm, with a visible transmittance over 85%, which is well above the reported for such a low level of MWCNTs loading. The electrical conductivity of the composite was measured at 120 degrees C. It has been observed that electrical conductivity increases significantly with the increase in temperature, signifying the semiconducting nature of nano-composites. Finally, current-voltage (I-V) characteristics show liner behaviour, confirms Ohmic nature of nano-composites and metal contact. PMID:24734695

Nayak, Sasmita; Behura, Sanjay Kumar; Bhattacharjee, Sarama; Singh, Bimal P; Jani, Omkar; Mukhopadhyay, Indrajit

2014-04-01

257

Study on Ag mesh/conductive oxide hybrid transparent electrode for film heaters.  

PubMed

Ag mesh-indium tin oxide (ITO) hybrid transparent conductive films were fabricated and evaluated for use in film heaters. PS monolayer templates were prepared using highly mono-dispersed PS spheres (11.2 ?m) obtained by a filtering process with micro-sieves. At first, three Ag meshes with different sheet resistances (20, 100, and 300 ? sq(-1)) and transmittances (70, 73, and 76%) were evaluated for film heaters in terms of voltage and long-term stability. Subsequently, in an effort to obtain better transmittance, Ag mesh-ITO hybrid heaters were fabricated utilizing finite ITO depositions. At the optimised ITO thickness (15 nm), the sheet resistance and the transmittance were 300 ? sq(-1) and 88%, respectively, which indicates that this material is a good potential candidate for an efficient defroster in vehicles. PMID:24916322

Kwon, Namyong; Kim, Kyohyeok; Heo, Jinhee; Yi, Insook; Chung, Ilsub

2014-07-01

258

Study on Ag mesh/conductive oxide hybrid transparent electrode for film heaters  

NASA Astrophysics Data System (ADS)

Ag mesh-indium tin oxide (ITO) hybrid transparent conductive films were fabricated and evaluated for use in film heaters. PS monolayer templates were prepared using highly mono-dispersed PS spheres (11.2 ?m) obtained by a filtering process with micro-sieves. At first, three Ag meshes with different sheet resistances (20, 100, and 300 ? sq?1) and transmittances (70, 73, and 76%) were evaluated for film heaters in terms of voltage and long-term stability. Subsequently, in an effort to obtain better transmittance, Ag mesh-ITO hybrid heaters were fabricated utilizing finite ITO depositions. At the optimised ITO thickness (15 nm), the sheet resistance and the transmittance were 300 ? sq?1 and 88%, respectively, which indicates that this material is a good potential candidate for an efficient defroster in vehicles.

Kwon, Namyong; Kim, Kyohyeok; Heo, Jinhee; Yi, Insook; Chung, Ilsub

2014-07-01

259

Uniform and ordered copper nanomeshes by microsphere lithography for transparent electrodes.  

PubMed

We report a comprehensive simulation and experimental study on the optical and electronic properties of uniform and ordered copper nanomeshes (Cu NMs) to determine their performance for transparent conductors. Our study includes simulations to determine the role of propagating modes in transmission and experiments that demonstrate a scalable, facile microsphere-based method to fabricate NMs on rigid quartz and flexible polyethylene terephthalate substrates. The fabrication method allows for precise control over NM morphology with near-perfect uniformity and long-range order over large areas on rigid substrates. Our Cu NMs demonstrate 80% diffuse transmission at 17 ?/square on quartz, which is comparable to indium tin oxide. We also performed durability experiments that demonstrate these Cu NMs are robust from bending, heating, and abrasion. PMID:24601761

Gao, Tongchuan; Wang, Baomin; Ding, Bo; Lee, Jung-kun; Leu, Paul W

2014-04-01

260

Silver nanowire composite thin films as transparent electrodes for Cu(In,Ga)Se2/ZnS thin film solar cells.  

PubMed

Solution processed silver nanowire indium-tin oxide nanoparticle (AgNW-ITONP) composite thin films were successfully applied as the transparent electrodes for Cu(In,Ga)Se2 (CIGS) thin film solar cells with ZnS buffer layers. Properties of the AgNW-ITONP thin film and its effects on performance of CIGS/ZnS thin film solar cells were studied. Compared with the traditional sputtered ITO electrodes, the AgNW-ITONP thin films show comparable optical transmittance and electrical conductivity. Furthermore, the AgNW-ITONP thin film causes no physical damage to the adjacent surface layer and does not need high temperature annealing, which makes it very suitable to use as transparent conductive layers for heat or sputtering damage-sensitive optoelectronic devices. By using AgNW-ITONP electrodes, the required thickness of the ZnS buffer layers for CIGS thin film solar cells was greatly decreased. PMID:24922214

Tan, Xiao-Hui; Chen, Yu; Liu, Ye-Xiang

2014-05-20

261

Dye-sensitized solar cells based on hydroquinone/benzoquinone as bio-inspired redox couple with different counter electrodes.  

PubMed

In the present study, tetramethylammonium hydroquinone (HQ)/benzoquinone (BQ) were developed for use as a redox couple, with poly(3,4-ethylenedioxythiophene) (PEDOT) and multiwalled carbon nanotubes (MWNT) being proposed for use as counter electrode (CE) catalysts in dye-sensitized solar cells (DSSCs). Both metal-complex N719 and metal-free organic dye CM309 were employed to fabricate devices. For the devices sensitized by N719, when using PEDOT and MWNT CEs, power conversion efficiencies (PCE) of 5.2 and 4.9% were obtained, respectively, which were much higher than that of the device using the traditional Pt CE (4.7%) when HQ/BQ electrolyte was employed. However, with the HQ/BQ redox shuttle, the efficiency of the devices sensitized by N719 is much lower than that of the devices when the traditional I(-)/I3(-) based electrolyte and Pt CE were employed (7.9%). While for the CM309 sensitized solar cells, when the HQ/BQ redox shuttle was employed, PEDOT and MWNT performed much better than Pt, the DSSC using the PEDOT CE showed an efficiency of 6.2%, which was close to that of the DSSC using the traditional I(-)/I3(-) electrolyte and Pt CE (6.3%). PMID:23925069

Cheng, Ming; Yang, Xichuan; Chen, Cheng; Zhao, Jianghua; Zhang, Fuguo; Sun, Licheng

2013-09-28

262

MgO nano-facet embedded silver-based dielectric/metal/dielectric transparent electrode.  

PubMed

We replace Indium Tin Oxide (ITO) with an MgO nano-facet Embedded WO(3)/Ag/WO(3)(WAW) multilayer for electrodes of high efficiency OLEDs. WAW shows higher values for transmittance (93%) and conductivity (1.3×10(5) S/cm) than those of ITO. Moreover, WAW shows higher transmittance (92.5%) than that of ITO (86.4%) in the blue region (<500 nm). However, due to the large difference in refractive indices (n) of glass (n=1.55) and WO(3) (n=1.95), the incident light has a small critical angle (52°). Thus, the generated light is confined by the glass/WAW interface, resulting in low light outcoupling efficiency (~20%). This can be enhanced by using a nano-facet structured MgO (n=1.73) layer and a ZrO(2) (n=1.84) layer as a graded index layer. Using these optimized electrodes, ITO-free, OLEDs with various emission wavelengths have been produced. The luminance of OLEDs using MgO/ZrO(2)/WAW layers is enhanced by 24% compared to that of devices with ITO. PMID:22274430

Kim, Sungjun; Yu, Hak Ki; Hong, Kihyon; Kim, Kisoo; Son, Jun Ho; Lee, Illhwan; Kim, Kyoung-Bo; Kim, Tae-Yeob; Lee, Jong-Lam

2012-01-16

263

Opto-Electric Cellular Biosensor Using Optically Transparent Indium Tin Oxide (ITO) Electrodes  

PubMed Central

Indium tin oxide (ITO) biosensors are used to perform simultaneous optical and electrical measurements in order to examine the dynamic cellular attachment, spreading, and proliferation of endothelial cells (ECs) as well as cytotoxic effects when exposed to cytochalasin D. A detailed description of the fabrication of these sensors is provided and their superior optical characteristics are qualitatively shown using four different microscopic images. Differential interference contrast microscopy (DICM) images were acquired simultaneously with micro-impedance measurements as a function of frequency and time. A digital image processing algorithm quantified the cell-covered electrode area as a function of time. In addition, cytotoxicity effects, produced by the toxic agent cytochalasin D, were examined using micro-impedance measurements, confocal microscopy images of stained actin-filaments, and interference reflection contrast microscopy (IRCM) capable of examining the bottom morphology of a cell. The results of this study show (1) the dynamic optical and electrical cellular characteristics using optically thin ITO biosensors; (2) qualitative agreement between cell-covered electrode area and electrical impedance during cellular attachment; (3) in vitro cytotoxicity detection of ECs due to 3 ?M cytochalasin D. The present opto-electric biosensor system is unique in that a simultaneous and integrated cellular analysis is possible for a variety of living cells.

Choi, Chang K.; Margraves, Chuck H.; Jun, Seung I.; English, Anthony E.; Rack, Philip D.; Kihm, Kenneth D.

2008-01-01

264

Effect of surface modification of multi-walled carbon nanotubes on the fabrication and performance of carbon nanotube based counter electrodes for dye-sensitized solar cells  

Microsoft Academic Search

A polymeric surface modifier for multi-walled carbon nanotube (CNT) was prepared through living radical polymerization technique and applied to CNT paste for the preparation of carbon based counter electrode for dye-sensitized solar cell. Poly(maleic anhydride-co-p-acetoxystyrene)-block-poly(p-acetoxystyrene) was first prepared through nitroxide mediated polymerization (NMP) technique, followed by introduction of pyrene units to the polymer backbone through imidization reaction. Hydrolysis reaction was

Hee Jung Choi; Jeong Eun Shin; Gi-Won Lee; Nam-Gyu Park; Kyungkon Kim; Sung Chul Hong

2010-01-01

265

Low-cost and high-performance CoMoS4 and NiMoS4 counter electrodes for dye-sensitized solar cells.  

PubMed

Porous chalcogels CoMoS4 and NiMoS4 made by a facile solution reaction displayed good electrocatalytic activity in the redox reaction of the I(-)/I3(-) shuttle. Dye-sensitized solar cells with these ternary compounds as counter electrodes (CEs) showed photovoltaic performance similar to the devices made with noble metal platinum CE (7.46%). PMID:24022304

Zheng, Xiaojia; Guo, Jiahao; Shi, Yantao; Xiong, Fengqiang; Zhang, Wen-Hua; Ma, Tingli; Li, Can

2013-10-25

266

Highly efficient Mo2C nanotubes as a counter electrode catalyst for organic redox shuttles in dye-sensitized solar cells.  

PubMed

Molybdenum carbide nanotubes (Mo2C-NTs) were synthesized and showed remarkable catalytic activity for regeneration of an organic sulfide redox shuttle. The dye-sensitized solar cells (DSCs) using Mo2C-NTs as the counter electrode (CE) showed a high power conversion efficiency of 6.22%, which is much higher than the DSCs using a conventional Pt CE (3.91%). PMID:24895688

Wu, Mingxing; Lin, Ya-Nan; Guo, Hongyue; Wu, Kezhong; Lin, Xiao

2014-06-19

267

A nonstoichiometric SnO2-? nanocrystal-based counter electrode for remarkably improving the performance of dye-sensitized solar cells.  

PubMed

We report the fabrication of a highly active nonstoichiometric SnO2-? based counter electrode for dye-sensitized solar cells (DSSCs). The introduction of oxygen vacancies into SnO2 results in a much lower charge transfer resistance and a higher polarization current density. The solar energy conversion efficiency of the SnO2-? based DSSCs is increased by 67%. PMID:24849132

Pan, Jian; Wang, Lianzhou; Yu, Jimmy C; Liu, Gang; Cheng, Hui-Ming

2014-07-01

268

Template-free and filamentary growth of silver nanowires: application to anisotropic conductive transparent flexible electrodes.  

PubMed

Silver nanowires (NWs) are currently fabricated via template-free or template-assisted methods. The former is based on a medium-mediated anisotropic synthesis, which enables precursor atoms to be selectively adsorbed onto specific crystallographic planes, and the latter is performed via directional growth guided by preformed templates. These methods are costly and complicated. We outline a facile and low-cost approach for the electrochemical synthesis of silver NWs in a manner that is template- and surfactant-free and that provides control over the NW diameter in the range of 80 to 800 nm by the repetition of nucleation and dissolution. The nanowires vertically grow with the help of the interface anisotropy driven by a field enhancement at the tips of the islands nucleated on the substrate in ultra-dilute electrolytes (ca. 10(-5) M), which is similar to a lightning-rod effect. The silver nanowires of vertical configuration are utilized for fabrication of anisotropic conducting, transparent, and flexible films. PMID:23348502

Park, Sun Hwa; Shin, Ho Sun; Kim, Young Heon; Park, Hyun Min; Song, Jae Yong

2013-03-01

269

Mechanical Integrity of Flexible In--Zn--Sn--O Film for Flexible Transparent Electrode  

NASA Astrophysics Data System (ADS)

The mechanical integrity of transparent In--Zn--Sn--O (IZTO) films is investigated using outer/inner bending, stretching, and twisting tests. Amorphous IZTO films are grown using a pulsed DC magnetron sputtering system with an IZTO target on a polyimide substrate at room temperature. Changes in the optical and electrical properties of IZTO films depend on the oxygen partial pressure applied during the film deposition process. In the case of 3% oxygen partial pressure, the IZTO films exhibit s resistivity of 8.3× 10-4 ? cm and an optical transmittance of 86%. The outer bending test shows that the critical bending radius decreases from 10 to 7.5 mm when the oxygen partial pressure is increased from 1 to 3%. The inner bending test reveals that the critical bending radius of all IZTO films is 3.5 mm regardless of oxygen partial pressure. The IZTO films also show excellent mechanical reliability in the bending fatigue tests of more than 10,000 cycles. In the uniaxial stretching tests, the electrical resistance of the IZTO film does not change until a strain of 2.4% is reached. The twisting tests demonstrate that the electrical resistance of IZTO films remains unchanged up to 25°. These results suggest that IZTO films have excellent mechanical durability and flexibility in comparison with already reported crystallized indium tin oxide (ITO) films.

Kim, Young Sung; Oh, Se-In; Choa, Sung-Hoon

2013-05-01

270

Numerical and experimental study of SnOx | Ag | SnOx multilayer as indium-free transparent electrode for organic solar cells  

NASA Astrophysics Data System (ADS)

We propose a SnOx | Ag | SnOx multilayer, deposited in a continuous vacuum atmosphere by E-beam evaporation, as transparent anode for a (poly-3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk heterojunction based Organic Solar Cell (OSC). Optical characterization of the deposited SnOx is performed to determine the dispersion of the complex refractive index. A Transfer Matrix Method (TMM) numerical optimization of the thicknesses of each layer of the electrode is realized to limit the number of manufactured samples. A numerical study using the morphology of the silver inserted between the oxide layers as input data is performed with a Finite Difference Time Domain (FDTD) method to improve the accordance between measurement and optical model. Multilayers are manufactured with the objective to give to the electrode its best conductivity and transparency in the visible spectral range by using the results of the optical optimization. These bare tri-layer electrodes show low sheet resistance (<10 ?/?) and mean transparency on [400-700] nm spectral band as high as 67 % for the whole Glass | SnOx | Ag | SnOx structure. The trilayer is then numerically studied inside a P3HT:PCBM bulk heterojunction based OSC structure. Intrinsic absorption inside the sole active layer is calculated giving the possibility to perform optical optimization on the intrinsic absorption efficiency inside the active area by considering the media embedding the electrodes.

Bou, Adrien; Torchio, Philippe; Barakel, Damien; Thierry, François; Thoulon, Pierre-Yves; Ricci, Marc

2014-03-01

271

Laser synthesized super-hydrophobic conducting carbon with broccoli-type morphology as a counter-electrode for dye sensitized solar cells  

NASA Astrophysics Data System (ADS)

A laser photochemical process is introduced to realize superhydrophobic conducting carbon coatings with broccoli-type hierarchical morphology for use as a metal-free counter electrode in a dye sensitized solar cell. The process involves pulsed excimer laser irradiation of a thin layer of liquid haloaromatic organic solvent o-dichlorobenzene (DCB). The coating reflects a carbon nanoparticle-self assembled and process-controlled morphology that yields solar to electric power conversion efficiency of 5.1% as opposed to 6.2% obtained with the conventional Pt-based electrode.A laser photochemical process is introduced to realize superhydrophobic conducting carbon coatings with broccoli-type hierarchical morphology for use as a metal-free counter electrode in a dye sensitized solar cell. The process involves pulsed excimer laser irradiation of a thin layer of liquid haloaromatic organic solvent o-dichlorobenzene (DCB). The coating reflects a carbon nanoparticle-self assembled and process-controlled morphology that yields solar to electric power conversion efficiency of 5.1% as opposed to 6.2% obtained with the conventional Pt-based electrode. Electronic supplementary information (ESI) available: Materials and equipment details, solar cell fabrication protocol, electrolyte spreading time measurement details, XPS spectra, electronic study, film adhesion test detailed analysis and field emission results. See DOI: 10.1039/c2nr32082g

Gokhale, Rohan; Agarkar, Shruti; Debgupta, Joyashish; Shinde, Deodatta; Lefez, Benoit; Banerjee, Abhik; Jog, Jyoti; More, Mahendra; Hannoyer, Beatrice; Ogale, Satishchandra

2012-10-01

272

Two-dimensional micropatterns via crystal growth of Na2CO3 for fabrication of transparent electrodes.  

PubMed

The simple and versatile method to generate two-dimensional micropatterns by controlling precisely crystallization of sodium carbonate (Na2CO3) was investigated. Dense clusters of dendrites of salt crystals were homogeneously formed in a large area with an aqueous solution of Na2CO3 during evaporation of water. The dimensions and morphologies of dendritic salt crystals were tuned by changing the growth conditions such as salt concentration, relative humidity, and temperature. Then, 2D micropatterns of salt crystals were directly used as a mask for the deposition of a silver (Ag) layer to fabricate transparent electrodes. After salt crystals were completely dissolved in water, the network of an electrically conductive Ag layer, whose patterns were reversely produced from salt crystals, was generated on glass substrates. In addition, salt crystals were used as a master to prepare a replica mold of poly(dimethylsiloxane) (PDMS) for utilizing the imprinting technique. By imprinting a flexible PDMS mold with Ag inks, Ag micropatterns that were perfectly identical to dendrites of salt crystals were transferred to the other substrate. PMID:24003886

Lee, Dong-Eun; Go, SeungJae; Hwang, GyungSeok; Chin, Byung Doo; Lee, Dong Hyun

2013-10-01

273

Synthesis of Cu2ZnSnS4 Nanoparticles for Applications as Counter Electrodes of CdS Quantum Dot-Sensitized Solar Cells  

NASA Astrophysics Data System (ADS)

Cu2ZnSnS4 (CZTS) nanoparticles have been synthesized through a one-step solvothermal route, which exhibited a nearly single kesterite structure with a fundamental band gap of ˜1.54 eV. Quantum dots-sensitized solar cells were fabricated based on CZTS counter electrodes and CdS QD-sensitized TiO2 NRs photoelectrodes with various thicknesses of QD sensitization layers. The cells based on a CZTS electrode, compared with other single-layer DSSCs in this study, had the highest conversion efficiency of 0.27% (for CdS layer numbers of 9), which was obviously higher than Pt. The performance improvement was attributed to the better stability, sunlight sensitivity, and the resulting photoelectrocatalytic activity of the CZTS electrodes.

Gu, Xiuquan; Zhang, Shuang; Qiang, Yinghuai; Zhao, Yulong; Zhu, Lei

2014-05-01

274

Discharge amplified photo-emission from ultra-thin films applied to tuning work function of transparent electrodes in organic opto-electronic devices  

NASA Astrophysics Data System (ADS)

A novel photoemission technique utilising localised discharge amplification of photo-yield is reported. It enables fast, accurate measurement of work function and ionisation potential for ultra-thin buffer layers vacuum deposited onto single and multilayer transparent conducting electrodes for organic solar cells and OLED's. Work function in most traditional transparent electrodes has to be raised to maximise charge transfer while high transmittance and high conductance must be retained. Results are presented for a range of metal oxide buffers, which achieve this goal. This compact photo-yield spectroscopy tool with its fast turn-around has been a valuable development aid since ionisation potential can vary significantly as deposition conditions change slightly, and as ultra-thin films grow. It has also been useful in tracking the impact of different post deposition cleaning treatments along with some storage and transport protocols, which can adversely reduce ionisation potential and hence subsequent device performance.

Gentle, A. R.; Smith, G. B.; Watkins, S. E.

2013-11-01

275

Organic Solar Cells with Hydrogenated In-Doped ZnO Replacing Sn-Doped In2O3 as Transparent Electrode  

Microsoft Academic Search

Hydrogenated In-doped ZnO (IZO:H) anodic films grown at different ratios (R) of hydrogen to argon were deposited at a low processing temperature of 100 °C on a glass substrate by pulsed DC magnetron sputtering for photovoltaic cells. Even at a low substrate temperature, the transparent electrode showed an average optical transmittance of 88% in the visible range and a reduced

Young Ran Park; Donggeun Jung; Young Sung Kim

2008-01-01

276

Large-area transparent conductive few-layer graphene electrode in GaN-based ultra-violet light-emitting diodes  

Microsoft Academic Search

We report on the development of a large-area few-layer graphene (FLG)--based transparent conductive electrode as a current spreading layer for GaN-based ultraviolet (UV) light-emitting diodes (LEDs). Large-area FLG was deposited on Cu using the chemical vapor deposition (CVD) method and subsequently transferred to the surface of the UV LED. UV light at a peak of 372 nm was emitted through

Byung-Jae Kim; Chongmin Lee; Younghun Jung; Kwang Hyeon Baik; Michael A. Mastro; Jennifer K. Hite; Charles R. Eddy; Jihyun Kim

2011-01-01

277

Enhancing light out-coupling of organic light-emitting devices using indium tin oxide-free low-index transparent electrodes  

NASA Astrophysics Data System (ADS)

With its increasing and sufficient conductivity, the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been capable of replacing the widely used but less cost-effective indium tin oxides (ITOs) as alternative transparent electrodes for organic light-emitting devices (OLEDs). Intriguingly, PEDOT:PSS also possesses an optical refractive index significantly lower than those of ITO and typical organic layers in OLEDs and well matching those of typical OLED substrates. Optical simulation reveals that by replacing ITO with such a low-index transparent electrode, the guided modes trapped within the organic/ITO layers in conventional OLEDs can be substantially suppressed, leading to more light coupled into the substrate than the conventional ITO device. By applying light out-coupling structures onto outer surfaces of substrates to effectively extract radiation into substrates, OLEDs using such low-index transparent electrodes achieve enhanced optical out-coupling and external quantum efficiencies in comparison with conventional OLEDs using ITO.

Huang, Yi-Hsiang; Lu, Chun-Yang; Tsai, Shang-Ta; Tsai, Yu-Tang; Chen, Chien-Yu; Tsai, Wei-Lung; Lin, Chun-Yu; Chang, Hong-Wei; Lee, Wei-Kai; Jiao, Min; Wu, Chung-Chih

2014-05-01

278

Cherenkov Counters  

NASA Astrophysics Data System (ADS)

When a charged particle passes through an optically transparent medium with a velocity greater than the phase velocity of light in that medium, it emits prompt photons, called Cherenkov radiation, at a characteristic polar angle that depends on the particle velocity. Cherenkov counters are particle detectors that make use of this radiation. Uses include prompt particle counting, the detection of fast particles, the measurement of particle masses, and the tracking or localization of events in very large, natural radiators such as the atmosphere, or natural ice fields, like those at the South Pole in Antarctica. Cherenkov counters are used in a number of different fields, including high energy and nuclear physics detectors at particle accelerators, in nuclear reactors, cosmic ray detectors, particle astrophysics detectors and neutrino astronomy, and in biomedicine for labeling certain biological molecules.

Ratcliff, Blair; Schwiening, Jochen

279

Cherenkov Counters  

SciTech Connect

When a charged particle passes through an optically transparent medium with a velocity greater than the phase velocity of light in that medium, it emits prompt photons, called Cherenkov radiation, at a characteristic polar angle that depends on the particle velocity. Cherenkov counters are particle detectors that make use of this radiation. Uses include prompt particle counting, the detection of fast particles, the measurement of particle masses, and the tracking or localization of events in very large, natural radiators such as the atmosphere, or natural ice fields, like those at the South Pole in Antarctica. Cherenkov counters are used in a number of different fields, including high energy and nuclear physics detectors at particle accelerators, in nuclear reactors, cosmic ray detectors, particle astrophysics detectors and neutrino astronomy, and in biomedicine for labeling certain biological molecules.

Barbero, Marlon

2012-04-19

280

Very long Ag nanowire synthesis and its application in a highly transparent, conductive and flexible metal electrode touch panel  

NASA Astrophysics Data System (ADS)

The future electronics will be soft, flexible and even stretchable to be more human friendly in the form of wearable computers. However, conventional electronic materials are usually brittle. Recently, carbon based materials are intensively investigated as a good candidate for flexible electronics but with limited mechanical and electrical performances. Metal is still the best material for electronics with great electrical properties but with poor transparency and mechanical performance. Here we present a simple approach to develop a synthesis method for very long metallic nanowires and apply them as new types of high performance flexible and transparent metal conductors as an alternative to carbon nanotubes, graphene and short nanowire based flexible transparent conductors and indium tin oxide based brittle transparent conductors. We found that very long metallic nanowire network conductors combined with a low temperature laser nano-welding process enabled superior transparent flexible conductors with high transmittance and high electrical conductivity. Further, we demonstrated highly flexible metal conductor LED circuits and transparent touch panels. The highly flexible and transparent metal conductors can be mounted on any non-planar surfaces and applied for various opto-electronics and ultimately for future wearable electronics.The future electronics will be soft, flexible and even stretchable to be more human friendly in the form of wearable computers. However, conventional electronic materials are usually brittle. Recently, carbon based materials are intensively investigated as a good candidate for flexible electronics but with limited mechanical and electrical performances. Metal is still the best material for electronics with great electrical properties but with poor transparency and mechanical performance. Here we present a simple approach to develop a synthesis method for very long metallic nanowires and apply them as new types of high performance flexible and transparent metal conductors as an alternative to carbon nanotubes, graphene and short nanowire based flexible transparent conductors and indium tin oxide based brittle transparent conductors. We found that very long metallic nanowire network conductors combined with a low temperature laser nano-welding process enabled superior transparent flexible conductors with high transmittance and high electrical conductivity. Further, we demonstrated highly flexible metal conductor LED circuits and transparent touch panels. The highly flexible and transparent metal conductors can be mounted on any non-planar surfaces and applied for various opto-electronics and ultimately for future wearable electronics. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr31254a

LeeThese Two Authors Contributed Equally To This Article., Jinhwan; Lee, Phillip; Lee, Hyungman; Lee, Dongjin; Lee, Seung Seob; Ko, Seung Hwan

2012-09-01

281

Electrochemiluminescent microoptoprobe with mini-grid working electrode and self-contained sample container  

Microsoft Academic Search

A new electrochemiluminescence (ECL) microoptoprobe with simple structure, small sampling volume and high efficiency was developed. It was constructed by fixing the transparent gold mini-grid on the end surface of the optical fiber, and by surrounding the fiber with the counter- and reference electrodes to form a self-contained three-electrode system. The use of mini-grid electrode increased the surface area and

Haiyan Wang; Guobao Xu; Shaojun Dong

2002-01-01

282

Preparation of nitrogen-doped TiO?/graphene nanohybrids and application as counter electrode for dye-sensitized solar cells.  

PubMed

The preparation of nitrogen-doped TiO2/graphene nanohybrids and their application as counter electrode for dye-sensitized solar cell (DSSC) are presented. These nanohybrids are prepared by self-assembly of pyrene modified H2Ti3O7 nanosheets and graphene in aqueous medium via ?-? stacking interactions, followed by thermal calcination at different temperatures in ammonia atmosphere to afford nitrogen-doped TiO2/graphene nanohybrids. H2Ti3O7 nanosheets were synthesized from TiOSO4·xH2O by a hydrothermal reaction at 150 °C for 48 h. The microstructure of the obtained mixed-phase nanohybrids was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transforms infrared spectroscopy (FTIR). Moreover, the performances of the as-prepared nanohybrids as counter electrode materials for DSSC was investigated, and the results indicated that the nanohybrids prepared at higher nitridation temperature would lead to higher short-circuit current density than those prepared at lower nitridation temperature, indicating that it can be utilized as a low-cost alternative to Pt for DSSCs and other applications. PMID:24409807

Wang, Rui; Wu, Qingduan; Lu, Yun; Liu, Hongwei; Xia, Yanzhi; Liu, Jingquan; Yang, Dongjiang; Huo, Ziyang; Yao, Xiangdong

2014-02-12

283

Very long Ag nanowire synthesis and its application in a highly transparent, conductive and flexible metal electrode touch panel.  

PubMed

The future electronics will be soft, flexible and even stretchable to be more human friendly in the form of wearable computers. However, conventional electronic materials are usually brittle. Recently, carbon based materials are intensively investigated as a good candidate for flexible electronics but with limited mechanical and electrical performances. Metal is still the best material for electronics with great electrical properties but with poor transparency and mechanical performance. Here we present a simple approach to develop a synthesis method for very long metallic nanowires and apply them as new types of high performance flexible and transparent metal conductors as an alternative to carbon nanotubes, graphene and short nanowire based flexible transparent conductors and indium tin oxide based brittle transparent conductors. We found that very long metallic nanowire network conductors combined with a low temperature laser nano-welding process enabled superior transparent flexible conductors with high transmittance and high electrical conductivity. Further, we demonstrated highly flexible metal conductor LED circuits and transparent touch panels. The highly flexible and transparent metal conductors can be mounted on any non-planar surfaces and applied for various opto-electronics and ultimately for future wearable electronics. PMID:22952107

Lee, Jinhwan; Lee, Phillip; Lee, Hyungman; Lee, Dongjin; Lee, Seung Seob; Ko, Seung Hwan

2012-10-21

284

Improved photovoltaic effects in InGaN-based multiple quantum well solar cell with graphene on indium tin oxide nanodot nodes for transparent and current spreading electrode  

NASA Astrophysics Data System (ADS)

We implemented graphene network on indium tin oxide (ITO) nanodots to a transparent and current-spreading electrode in InGaN-based solar cell to improve power conversion efficiency. The external quantum efficiency and short circuit current density (Jsc) of solar cells with graphene network on ITO nanodots were enhanced compared to those of solar cells with ITO and bare graphene film. The increase of the power conversion efficiency is attributed to the high transmittance, internal light-scattering effect, and effective carrier absorption of ITO nanodots.

Hoon Seo, Tae; Shim, Jae-Phil; Jin Chae, Seung; Shin, GangU; Kyoung Kim, Bo; Lee, Dong-Seon; Hee Lee, Young; Suh, Eun-Kyung

2013-01-01

285

Indium-free transparent organic light emitting diodes with Al doped ZnO electrodes grown by atomic layer and pulsed laser deposition  

NASA Astrophysics Data System (ADS)

We present highly efficient transparent organic light emitting diodes (OLEDs) with Al doped ZnO (AZO) electrodes prepared by atomic layer deposition and pulsed laser deposition (PLD). The power and current efficiencies exceed 27 lm/W and 44 cd/A at a brightness level of 100 cd/m2, respectively. At the same time, the transmissivity of the devices is above 73% in the visible part of the spectrum. Owing to an efficient WO3 buffer layer and an optimized PLD process for the deposition of the top AZO electrode, the OLEDs show leakage current densities as low as 3×10-5 mA/cm2 at a reverse bias of 6 V. Therefore, our study paves the way for indium-free, see-through OLED displays.

Meyer, J.; Görrn, P.; Hamwi, S.; Johannes, H.-H.; Riedl, T.; Kowalsky, W.

2008-08-01

286

Laser welding of nanoparticulate TiO2 and transparent conducting oxide electrodes for highly efficient dye-sensitized solar cell  

NASA Astrophysics Data System (ADS)

Poor interfacial contact is often encountered in nanoparticulate film-based devices. The dye-sensitized solar cell (DSSC) is a representative case in which a nanoporous TiO2 electrode needs to be prepared on the transparent conducting oxide (TCO)-coated glass substrate. In this study, we demonstrate that the inter-electrode contact resistance accounts for a considerable portion of the total resistance of a DSSC and its efficiency can be greatly enhanced by welding the interface with a laser. TiO2 films formed on the TCO-coated glass substrate were irradiated with a pulsed ultraviolet laser beam at 355 nm this transmits through the TCO and glass but is strongly absorbed by TiO2. Electron microscopy analysis and impedance measurements showed that a thin continuous TiO2 layer is formed at the interface as a result of the local melting of TiO2 nanoparticles and this layer completely bridges the gap between the two electrodes, improving the current flow with a reduced contact resistance. We were able to improve the efficiency by 35-65% with this process. DSSCs fabricated using a homemade TiO2 paste revealed an efficiency improvement from ? = 3.3% to 5.4%, and an increase from 8.2% to 11.2% was achieved with the TiO2 electrodes made from a commercial paste.

Kim, Jinsoo; Kim, Jonghyun; Lee, Myeongkyu

2010-08-01

287

2D Graphene Oxide Nanosheets as an Adhesive Over-Coating Layer for Flexible Transparent Conductive Electrodes  

PubMed Central

In recent, highly transparent and flexible, two-dimensional (2D) graphene oxide (GO) nanosheet has been paid attention for various applications. Due to an existence of a large amount of oxygen functional groups, the single 2D GO nanosheet has an insulating, transparent, highly dispersible in the eco-friendly water, and hydrophilic property that has strong adhesion to the hydrophilic surface, which will be the best candidate for the use of an over-coating layer (OCL) and protecting layer for a conductive nanowire based indium-free transparent conductive film (TCF). The ultrathin 2D adhesive GO OCL nanosheet is expected to tightly hold silver nanowires (AgNWs), reduce sheet resistance and produce uniform TCF, providing complete solution that simultaneously solves a high haze, low transparency with a conventional OCL and mechanical instability in cases without a thick OCL. Our novel 2D insulating and hydrophilic GO OCL successfully provided a large-area, flexible, and highly transparent AgNW TCF.

Moon, In Kyu; Kim, Jae Il; Lee, Hanleem; Hur, Kangheon; Kim, Woon Chun; Lee, Hyoyoung

2013-01-01

288

Synthesis and characterization of highly stable optically passive CeO 2–ZrO 2 counter electrode  

Microsoft Academic Search

Transparent and adherent CeO2–ZrO2 thin films having film thicknesses ?543–598nm were spray deposited onto the conducting (fluorine doped tin oxide coated glass) substrates from a blend of equimolar concentrations of cerium nitrate hexahydrate and zirconium nitrate having different volumetric proportions (0–6vol.% of Zr) in methanol. CeO2–ZrO2 films were polycrystalline with cubic fluorite crystal structure and the crystallinity was improved with

A. K. Bhosale; P. S. Shinde; N. L. Tarwal; R. C. Pawar; P. M. Kadam; P. S. Patil

2010-01-01

289

Platinum/titanium bilayer deposited on polymer film as efficient counter electrodes for plastic dye-sensitized solar cells  

SciTech Connect

A surface-rich platinum/titanium bilayer was deposited on poly(ethylene naphthalate) film by vacuum sputtering as counterelectrode for plastic dye-sensitized solar cells (DSSCs). Compared to the electrodes made of pure Pt layer, this electrode maintained similar electrochemical catalytic effect at relative low Pt usage. Current-voltage characteristics of the plastic DSSC at this stage stand at 0.69 V on V{sub OC}, 9.97 mA/cm{sup 2} on I{sub SC}, 0.69 on fill factor, and 4.31% cell efficiency under AM1.5, 100 mW/cm{sup 2} illumination.

Ikegami, M.; Miyoshi, K.; Miyasaka, T.; Teshima, K.; Wei, T. C.; Wan, C. C.; Wang, Y. Y. [Graduate School of Engineering, Toin University of Yokohama, Yokohama, Kanagawa 225-8502 (Japan); Peccell Technologies, Inc., Yokohama, Kanagawa 225-8502 (Japan); Department of Chemical Engineering, National Tsing-Hua University, Hsin-Chu, Taiwan 30013 (China)

2007-04-09

290

Large-scale synthesis of Cu2SnS3 and Cu1.8S hierarchical microspheres as efficient counter electrode materials for quantum dot sensitized solar cells  

NASA Astrophysics Data System (ADS)

Exploration of new catalytic semiconductors with novel structures as counter electrode materials is a promising approach to improve performances of quantum dot sensitized solar cells (QDSSCs). In this work, nearly mono-disperse tetragonal Cu2SnS3 (CTS) and rhombohedral Cu1.8S hierarchical microspheres with nanometer-to-micrometer dimensions have been synthesized respectively via a simple solvothermal approach. These microspheres are also demonstrated as efficient counter electrode materials in solar cells using ZnO/ZnSe/CdSe nanocables as photoanode and polysulfide (Sn2-/S2-) solution as electrolyte. While copper sulfide is regarded as one of the most effective counter electrode materials in QDSSCs, we demonstrate the CTS microspheres to show higher electrocatalytic activity for the reduction of polysulfide electrolyte than the Cu1.8S microspheres. This contributes to obvious enhancement of photocurrent density (JSC) and fill factor (FF). Power conversion efficiency (PCE) is significantly enhanced from 0.25% for the cell using a pure FTO (SnO2:F) glass as counter electrode, to 3.65 and 4.06% for the cells using counter electrodes of FTO glasses coated respectively with Cu1.8S and CTS microspheres.Exploration of new catalytic semiconductors with novel structures as counter electrode materials is a promising approach to improve performances of quantum dot sensitized solar cells (QDSSCs). In this work, nearly mono-disperse tetragonal Cu2SnS3 (CTS) and rhombohedral Cu1.8S hierarchical microspheres with nanometer-to-micrometer dimensions have been synthesized respectively via a simple solvothermal approach. These microspheres are also demonstrated as efficient counter electrode materials in solar cells using ZnO/ZnSe/CdSe nanocables as photoanode and polysulfide (Sn2-/S2-) solution as electrolyte. While copper sulfide is regarded as one of the most effective counter electrode materials in QDSSCs, we demonstrate the CTS microspheres to show higher electrocatalytic activity for the reduction of polysulfide electrolyte than the Cu1.8S microspheres. This contributes to obvious enhancement of photocurrent density (JSC) and fill factor (FF). Power conversion efficiency (PCE) is significantly enhanced from 0.25% for the cell using a pure FTO (SnO2:F) glass as counter electrode, to 3.65 and 4.06% for the cells using counter electrodes of FTO glasses coated respectively with Cu1.8S and CTS microspheres. Electronic supplementary information (ESI) available: SEM images of ZnO/ZnSe/CdSe nanocables and Nyquist plots of real solar cells containing various counter electrodes and the same photoanode of ZnO/ZnSe/CdSe nanocables. See DOI: 10.1039/c2nr31724a

Xu, Jun; Yang, Xia; Wong, Tai-Lun; Lee, Chun-Sing

2012-09-01

291

Photoresist-Free Patterning by Mechanical Abrasion of Water-Soluble Lift-Off Resists and Bare Substrates: Toward Green Fabrication of Transparent Electrodes  

PubMed Central

This paper describes the fabrication of transparent electrodes based on grids of copper microwires using a non-photolithographic process. The process—“abrasion lithography”—takes two forms. In the first implementation (Method I), a water-soluble commodity polymer film is abraded with a sharp tool, coated with a conductive film, and developed by immersion in water. Water dissolves the polymer film and lifts off the conductive film in the unabraded areas. In the second implementation (Method II), the substrate is abraded directly by scratching with a sharp tool (i.e., no polymer film necessary). The abraded regions of the substrate are recessed and roughened. Following deposition of a conductive film, the lower profile and roughened topography in the abraded regions prevents mechanical exfoliation of the conductive film using adhesive tape, and thus the conductive film remains only where the substrate is scratched. As an application, conductive grids exhibit average sheet resistances of 17 ? sq–1 and transparencies of 86% are fabricated and used as the anode in organic photovoltaic cells in concert with the conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). Compared to devices in which PEDOT:PSS alone serves as an anode, devices comprising grids of copper/nickel microwires and PEDOT:PSS exhibit lowered series resistance, which manifests in greater fill factor and power conversion efficiency. This simple method of forming micropatterns could find use in applications where cost and environmental impact should be minimized, especially as a potential replacement for the transparent electrode indium tin oxide (ITO) in thin-film electronics over large areas (i.e., solar cells) or as a method of rapid prototyping for laboratory-scale devices.

Printz, Adam D.; Chan, Esther; Liong, Celine; Martinez, Rene S.; Lipomi, Darren J.

2013-01-01

292

Podlike N-Doped Carbon Nanotubes Encapsulating FeNi Alloy Nanoparticles: High-Performance Counter Electrode Materials for Dye-Sensitized Solar Cells.  

PubMed

Podlike nitrogen-doped carbon nanotubes encapsulating FeNi alloy nanoparticles (Pod(N)-FeNi) were prepared by the direct pyrolysis of organometallic precursors. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel polarization measurements revealed their excellent electrocatalytic activities in the I(-) /I3 (-) redox reaction of dye-sensitized solar cells (DSSCs). This is suggested to arise from the modification of the surface electronic properties of the carbon by the encapsulated metal alloy nanoparticles (NPs). Sequential scanning with EIS and CV further showed the high electrochemical stability of the Pod(N)-FeNi composite. DSSCs with Pod(N)-FeNi as the counter electrode (CE) presented a power conversion efficiency of 8.82?%, which is superior to that of the control device with sputtered Pt as the CE. The Pod(N)-FeNi composite thus shows promise as an environmentally friendly, low-cost, and highly efficient CE material for DSSCs. PMID:24800923

Zheng, Xiaojia; Deng, Jiao; Wang, Nan; Deng, Dehui; Zhang, Wen-Hua; Bao, Xinhe; Li, Can

2014-07-01

293

Universal Low-Temperature MWCNT-COOH-Based Counter Electrode and a New Thiolate/Disulfide Electrolyte System for Dye-Sensitized Solar Cells.  

PubMed

A new thiolate/disulfide organic-based electrolyte system composed of the tetrabutylammonium salt of 2-methyl-5-trifluoromethyl-2H-[1,2,4]triazole-3-thiol (S(-)) and its oxidized form 3,3'-dithiobis(2-methyl-5-trifluoromethyl-2H-[1,2,4]triazole) (DS) has been formulated and used in dye-sensitized solar cells (DSSCs). The electrocatalytic activity of different counter electrodes (CEs) has been evaluated by means of measuring J-V curves, cyclic voltammetry, Tafel plots, and electrochemical impedance spectroscopy. A stable and low-temperature CE based on acid-functionalized multiwalled carbon nanotubes (MWCNT-COOH) was investigated with our S(-)/DS, I(-)/I3(-), T(-)/T2, and Co(II/III)-based electrolyte systems. The proposed CE showed superb electrocatalytic activity toward the regeneration of the different electrolytes. In addition, good stability of solar cell devices based on the reported electrolyte and CE was shown. PMID:24819923

Hilmi, Abdulla; Shoker, Tharallah A; Ghaddar, Tarek H

2014-06-11

294

Surfactant-free CuInS2 nanocrystals: an alternative counter-electrode material for dye-sensitized solar cells.  

PubMed

Surfactant-free CuInS2 (CIS) nanocrystals (NCs) were synthesized by replacing organic capping ligands with inorganic ions S(2-). The efficacy of ligand exchange was probed by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-vis spectroscopy, and Fourier-transform infrared (FTIR). The surfactant-free CIS NCs films were obtained by drop-casting onto the clean FTO glass. The electrical conductivity and electrocatalytic activity of CIS NCs films were sharply increased due to the improved interparticle coupling after ligand exchange. When the surfactant-free CIS films were used as counter electrode (CE) in dye-sensitized solar cells (DSSCs), a conversion efficiency of ? = 5.77% was achieved without sintering. PMID:23532636

Yao, Rong-Yue; Zhou, Zheng-Ji; Hou, Ze-Liang; Wang, Xia; Zhou, Wen-Hui; Wu, Si-Xin

2013-04-24

295

Printed transparent electrodes containing carbon nanotubes for elastic circuits applications with enhanced electrical durability under severe conditions  

Microsoft Academic Search

Organic composites filled with nanostructures are new group of materials with unique physical properties. Carbon nanotubes (CNTs) are demonstrating good electrical and mechanical properties. This enables to produce conductive polymer–CNT thick films optically transparent, which are highly useful in production of printed electronic paper. Currently used indium tin oxide (ITO) and antimony tin oxide (ATO) films exhibit high optical transmittance

Ma?gorzata Jakubowska; Marcin S?oma; Anna M?o?niak

2011-01-01

296

Semi-transparent metal electrode of Cu–Ni as a replacement of an ITO in organic photovoltaic cells  

Microsoft Academic Search

We demonstrate an indium-free organic photovoltaic cell that incorporates an ultrathin metal film as a semitransparent anode. In the proposed device structure, the indium tin oxide electrode is replaced by an ultrathin Cu–Ni bilayer. When an NiO is used as the hole transporting layer, the characteristic photovoltaic parameters of the cell fabricated with the metal electrode are similar to those

D. S. Ghosh; R. Betancur; T. L. Chen; V. Pruneri; Jordi Martorell

2011-01-01

297

Impurity-doped ZnO Thin Films Prepared by Physical Deposition Methods Appropriate for Transparent Electrode Applications in Thin-film Solar Cells  

NASA Astrophysics Data System (ADS)

This paper describes the development of transparent conducting impurity-doped ZnO thin films that would be appropriate for applications as transparent electrodes in thin-film solar cells. Transparent conducting Al-, B- and Ga-doped ZnO (AZO, BZO and GZO) thin films were prepared in a thickness range from 500 to 2000 nm on glass substrates at 200°C using various physical deposition methods: BZO films with vacuum arc plasma evaporation, AZO and GZO films with different types of magnetron sputtering depositions (MSDs) and all films with pulsed laser deposition (PLD). The suitability and stability of the electrical properties and, in addition, the suitability of the light scattering characteristics and surface texture formation were investigated in the prepared thin films. In particular, the suitability and stability evaluation was focused on the use of AZO, BZO and GZO thin films prepared by doping each impurity at an appropriate content to attain the lowest resistivity. The higher Hall mobility obtained in impurity-doped ZnO thin films with a resistivity on the order of 10-4 ?cm was related more to the content, i.e., the obtained carrier concentration, rather than the kind of impurity doped into the films. The stability of resistivity of the BZO thin films in long-term moisture-resistance tests (in air at 85% relative humidity and 85°C) was found to be lower than that of the AZO and GZO thin films. The surface texture formation was carried out by wet-chemical etching (in a 0.1% HCl solution at 25°C) conducted either before or after being heat-treated either with rapid thermal annealing (RTA) or without RTA. The suitability of the light scattering characteristics and the surface texture formation obtainable by wet-chemical etching (for use in transparent electrode applications) was considerably dependent on the deposition method used as well as whether the wet-chemical etching was conducted with or without RTA. A significant improvement of both transmittance and haze value at wavelengths up to about 1200 nm in the near-infrared region was attained in surface-textured AZO films that were prepared by r.f. power superimposed d.c. MSD as well as etched after being heat treated with RTA at 500°C for 5 min in air. The obtained suitability and stability in impurity-doped ZnO thin films were related more to the content rather than the kind of impurity doped into the films as well as to the deposition method used.

Minami, Tadatsugu; Miyata, Toshihiro; Nomoto, Jun-ichi

2012-04-01

298

Effect of electropolymerization time on the performance of poly(3,4-ethylenedioxythiophene) counter electrode for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Poly (3,4-ethylenedioxythiophene) (PEDOT) films were synthesized onto the fluorinated tin oxide (FTO) substrates as counter electrodes (CEs) for dye-sensitized solar cells (DSSCs) through an aqueous galvanostatic polymerization technique. Polymerization time was employed to control the surface morphologies and performances of the PEDOT films. The PEDOT electrodes showed faster reaction rate and higher electrocatalytic activity for I3- reduction as the polymerization time increased, which contributed to the increase of the open circuit voltage (VOC) for the DSSCs. The electrochemical impedance spectroscopy (EIS) indicated that charge transfer resistance (Rct) at CE/electrolyte interface decreased and then rebounded with the increasing polymerization time. Thus the short circuit photocurrent density (JSC) and fill factor (FF) of the DSSCs changed with the same trend. The energy conversion efficiency of the DSSC based on PEDOT CE up to 6.46% was achieved, which was higher than that based on Pt CE (6.33%). Therefore, the PEDOT film can be considered as a promising alternative CE for Pt-free DSSCs.

Gao, Mingqi; Xu, Youlong; Bai, Yang; Jin, Shaohua

2014-01-01

299

Dye sensitized solar cells (DSSCs) based on modified iron phthalocyanine nanostructured TiO 2 electrode and PEDOT:PSS counter electrode  

Microsoft Academic Search

An iron phthalocyanine with tetra-sulphonated substituents (FeTsPc) was used as photosentizer for the development of dye sensitized nanostructured TiO2 solar cells. The influence of surface modification (TiO2 film treated with HCl and HNO3) and thermal annealing of TiO2 photo-electrode on the performance of dye sensitized solar cell (DSSC) having structure FTO\\/TiO2–FeTsPc\\/electrolyte\\/PEDOT:PSS (carbon added)\\/FTO was investigated through the analysis of current–voltage

P. Balraju; Manish Kumar; M. S. Roy; G. D. Sharma

2009-01-01

300

Optimization of transparent and reflecting electrodes for amorphous silicon solar cells. Annual technical report, April 1, 1995--March 31, 1996  

SciTech Connect

The general objective is to develop methods to deposit materials which can be used to make more efficient solar cells. The work is organized into three general tasks: Task 1. Develop improved methods for depositing and using transparent conductors of fluorine-doped zinc oxide in amorphous silicon solar cells Task 2. Deposit and evaluate titanium oxide as a reflection-enhancing diffusion barrier between amorphous silicon and an aluminum or silver back-reflector. Task 3. Deposit and evaluate electrically conductive titanium oxide as a transparent conducting layer on which more efficient and more stable superstrate cells can be deposited. About one-third of the current project resources are allocated to each of these three objectives.

Gordon, R.G.; Sato, H.; Liang, H.; Liu, X.; Thornton, J. [Harvard Univ., Cambridge, MA (United States)

1996-08-01

301

A practical approach to the development of inkjet printable functional ionogels-bendable, foldable, transparent, and conductive electrode materials.  

PubMed

Ionic liquid gels, or ionogels, are semi-conductive, flexible materials, offering a host of tunable physical properties, gaining an increasing level of scientific interest. One of the challenges of this emerging category of materials is that the structure-process-property relationships are still empirically driven. In this study, a simple, practical approach is laid out to prepare standardized libraries of these materials, for the purpose of selecting transparent, flexible conductive formulations that can be dispensed using inkjet printing. The net result of this was the optimization of a PEG-DMA ionogel formulation exhibiting an optical transparency that was greater than 94% from near-UV to near-IR from a 150?µm thick films, and a resistivity of 12.4???·?m. PMID:21567620

Delaney, Joseph T; Liberski, Albert R; Perelaer, Jolke; Schubert, Ulrich S

2010-11-15

302

Metal\\/graphene sheets as p-type transparent conducting electrodes in GaN light emitting diodes  

Microsoft Academic Search

We demonstrate the use of graphene based transparent sheets as a p-type current spreading layer in GaN light emitting diodes (LEDs). Very thin Ni\\/Au was inserted between graphene and p-type GaN to reduce contact resistance, which reduced contact resistance from ~5.5 to ~0.6Omega\\/cm2, with no critical optical loss. As a result, LEDs with metal-graphene provided current spreading and injection into

Jung Min Lee; Hae Yong Jeong; Kyoung Jin Choi; Won Il Park

2011-01-01

303

Metal\\/graphene sheets as p-type transparent conducting electrodes in GaN light emitting diodes  

Microsoft Academic Search

We demonstrate the use of graphene based transparent sheets as a p-type current spreading layer in GaN light emitting diodes (LEDs). Very thin Ni\\/Au was inserted between graphene and p-type GaN to reduce contact resistance, which reduced contact resistance from ?5.5 to ?0.6?\\/cm2, with no critical optical loss. As a result, LEDs with metal-graphene provided current spreading and injection into

Jung Min Lee; Hae Yong Jeong; Kyoung Jin Choi; Won Il Park

2011-01-01

304

Voltammetric Membrane Chlorine Dioxide Electrode.  

National Technical Information Service (NTIS)

A voltammetric membrane electrode system has been modified and applied to the in situ measurement of chlorine dioxide. The electrode system consisted of a gold cathode, a silver/silver chloride reference electrode, and a gold counter electrode. Different ...

R. Dormond-Herrera K. H. Mancy

1980-01-01

305

Enhanced Light Output Power of Near-Ultraviolet Light-Emitting Diodes with Au-Doped Graphene for Transparent and Current-Spreading Electrode  

NASA Astrophysics Data System (ADS)

We report the implementation of Au-doped graphene film as a transparent and current-spreading electrode (TCSE) in GaN-based near-ultraviolet (UV) light-emitting diode (LED) to achieve good UV emission efficiency. The TCSE effects of Au-doped graphene film were clearly seen in both the electroluminescence (EL) and current--voltage (I--V) characteristics. The EL output power of 380-nm wavelength UV-LEDs with Au-doped graphene film was enhanced by about 20% at an injection current of 20 mA compared with that of conventional UV-LEDs. The increase of the light output power is attributed to the high UV transmittance of graphene, effective current spreading, and injection.

Seo, Tae Hoon; Chae, Seung Jin; Kim, Bo Kyoung; Shin, GangU; Lee, Young Hee; Suh, Eun-Kyung

2012-11-01

306

Ga-doped ZnO transparent electrodes with TiO2 blocking layer/nanoparticles for dye-sensitized solar cells  

PubMed Central

Ga-doped ZnO [GZO] thin films were employed for the transparent electrodes in dye-sensitized solar cells [DSSCs]. The electrical property of the deposited GZO films was as good as that of commercially used fluorine-doped tin oxide [FTO]. In order to protect the GZO and enhance the photovoltaic properties, a TiO2 blocking layer was deposited on the GZO surface. Then, TiO2 nanoparticles were coated on the blocking layer, and dye was attached for the fabrication of DSSCs. The fabricated DSSCs with the GZO/TiO2 glasses showed an enhanced conversion efficiency of 4.02% compared to the devices with the normal GZO glasses (3.36%). Furthermore, they showed better characteristics even than those using the FTO glasses, which can be attributed to the reduced charge recombination and series resistance.

2012-01-01

307

Highly transparent organic light-emitting diodes with a metallic top electrode: the dual role of a Cs2CO3 layer.  

PubMed

Highly transparent organic light-emitting diodes (TrOLEDs) are demonstrated using damage-free top cathodes of Cs2CO3/ Ag capped with ZnS layers. The presence of ultrathin Cs2CO3 layers not only improves the electron injection properties but also makes Ag thin films more continuous and uniform, resulting in ideal top electrodes with low sheet resistance and high transmittance. The combination of the uniform Ag morphology enabled by Cs2CO3 and the optimized thickness of ZnS capping layers results in TrOLEDs that have a peak transmittance as large as 80% with a luminous transmittance of 76.4%. These TrOLEDs exhibit a low turn-on voltage of 2.6V due to injection improvement by the Cs2CO3 layers. PMID:21263651

Cho, Hyunsu; Choi, Jung-Min; Yoo, Seunghyup

2011-01-17

308

Transparent cosputtered ITO-ZnO electrode ohmic contact to n-type ZnO for ZnO/GaN heterojunction light-emitting diode  

NASA Astrophysics Data System (ADS)

A transparent cosputtered ITO-ZnO film was used as an ohmic contact electrode to the n-type ZnO layer. The contact resistance of the ITO-ZnO/n-ZnO contact system was optimized by a rapid thermal annealing (RTA) treatment. Through x-ray diffraction and Auger electron spectroscopy depth profile measurements, the achievement on the ohmic contact of the ITO-ZnO/n-ZnO contact system was attributed to the outdiffusion of the oxygen atoms at the n-type ZnO layer surface, which was favourable for the increase of the electron carriers. By contrast, the mechanism responsible for the degradation of the contact resistance was due to the significant outdiffusion of the zinc atoms at the n-type ZnO layer surface, which also resulted in the marked peak shift of the Zn2In2O5 phase. The resulting n-ZnO/p-GaN heterojunction light-emitting diode fabrication, which used the transparent ITO-ZnO/n-ZnO ohmic contact system, exhibited rectifying behaviour and emitted a near-ultraviolet radiation at approximately 410 nm.

Ho, Chia-Cheng; Lai, Li-Wei; Lee, Ching-Ting; Yang, Kai-Chao; Lai, Bo-Ting; Liu, Day-Shan

2013-08-01

309

Low-temperature processing method of preparing for transparent graphene oxide electrode film with better electrical properties.  

PubMed

Graphene oxide films were prepared by a facile ball milling process. The milling time and the amount of the acryl type polymer dispersion agent were controlled to obtain well dispersed graphene oxide solution in ethanol. Consequently, the transparent and conducting graphene oxide film which had 69% transmittance and 1.5 x 10(6) ohm/sq surface resistance was produced by bar coating the solution on a PET substrate. The electrical property of the graphene oxide film could be further improved to 2.1 x 10(5) ohm/sq by hydrazine vapor reduction. PMID:22852393

Kim, Jin Ho; Jung, Jae Mok; Kwak, Jun Young; Hong, Seung-Soo; Gal, Yeong-Soon; Lim, Kwon Taek

2012-05-01

310

Workfunction-tunable, N-doped reduced graphene transparent electrodes for high-performance polymer light-emitting diodes.  

PubMed

Graphene is a promising candidate to complement brittle and expensive transparent conducting oxides. Nevertheless, previous research efforts have paid little attention to reduced graphene, which can be of great benefit due to low-cost solution processing without substrate transfer. Here we demonstrate workfunction-tunable, highly conductive, N-doped reduced graphene film, which is obtainable from the spin-casting of graphene oxide dispersion and can be successfully employed as a transparent cathode for high-performance polymer light-emitting diodes (PLEDs) as an alternative to fluorine-doped tin oxide (FTO). The sheet resistance of N-doped reduced graphene attained 300 ?/? at 80% transmittance, one of the lowest values ever reported from the reduction of graphene oxide films. The optimal doping of quaternary nitrogen and the effective removal of oxygen functionalities via sequential hydrazine treatment and thermal reduction accomplished the low resistance. The PLEDs employing N-doped reduced graphene cathodes exhibited a maximum electroluminescence efficiency higher than those of FTO-based devices (4.0 cd/A for FTO and 7.0 cd/A for N-doped graphene at 17,000 cd/m(2)). The reduced barrier for electron injection from a workfunction-tunable, N-doped reduced graphene cathode offered this remarkable device performance. PMID:22148918

Hwang, Jin Ok; Park, Ji Sun; Choi, Dong Sung; Kim, Ju Young; Lee, Sun Hwa; Lee, Kyung Eun; Kim, Yong-Hyun; Song, Myoung Hoon; Yoo, Seunghyup; Kim, Sang Ouk

2012-01-24

311

Efficient Organic Excitonic Solar Cells with Carbon Nanotubes Replacing In2O3:Sn as the Transparent Electrode (Presentation)  

SciTech Connect

The conclusions of this report are that: (1) organic solar cells with efficiencies of up to 1.43% conversion efficiency that use no ITO and no PEDOT:PSS, are demonstrated; (2) a cell without ITO, but with PEDOT:PSS gave 2.6% conversion efficiency; (3) due to porous nature of SWCNT substrates, optimization of the active layer is essential; and (4) SWCNT electrodes bring one step closer the goal of a fully printable, organic solar cell.

van de Lagemaat, J.; Barnes, T.; Rumbles, G.; Shaheen, S.; Coutts, T. J.; Weeks, C.; Glatkowski, P.; Levitsky, I.; Peltola, J.

2006-05-01

312

Metal/graphene sheets as p-type transparent conducting electrodes in GaN light emitting diodes  

NASA Astrophysics Data System (ADS)

We demonstrate the use of graphene based transparent sheets as a p-type current spreading layer in GaN light emitting diodes (LEDs). Very thin Ni/Au was inserted between graphene and p-type GaN to reduce contact resistance, which reduced contact resistance from ~5.5 to ~0.6?/cm2, with no critical optical loss. As a result, LEDs with metal-graphene provided current spreading and injection into the p-type GaN layer, enabling three times enhanced electroluminescent intensity compared with those with graphene alone. We confirmed very strong blue light emission in a large area of the metal-graphene layer by analyzing image brightness.

Min Lee, Jung; Yong Jeong, Hae; Jin Choi, Kyoung; Il Park, Won

2011-07-01

313

Catalytic, conductive, and transparent platinum nanofiber webs for FTO-free dye-sensitized solar cells.  

PubMed

We report a multifunctional platinium nanofiber (PtNF) web that can act as a catalyst layer in dye-sensitized solar cell (DSSC) to simultaneously function as a transparent counter electrode (CE), i.e., without the presence of an indium-doped tin oxide (ITO) or fluorine-doped tin oxide (FTO) glass. This PtNF web can be easily produced by electrospinning, which is highly cost-effective and suitable for large-area industrial-scale production. Electrospun PtNFs are straight and have a length of a few micrometers, with a common diameter of 40-70 nm. Each nanofiber is composed of compact, crystalline Pt grains and they are well-fused and highly interconnected, which should be helpful to provide an efficient conductive network for free electron transport and a large surface area for electrocatalytic behavior. A PtNF web is served as a counter electrode in DSSC and the photovoltaic performance increases up to a power efficiency of 6.0%. It reaches up to 83% of that in a conventional DSSC using a Pt-coated FTO glass as a counter electrode. Newly designed DSSCs containing PtNF webs display highly stable photoelectric conversion efficiencies, and excellent catalytic, conductive, and transparent properties, as well as long-term stability. Also, while the DSSC function is retained, the fabrication cost is reduced by eliminating the transparent conducting layer on the counter electrode. The presented method of fabricating DSSCs based on a PtNF web can be extended to other electrocatalytic optoelectronic devices that combine superior catalytic activity with high conductivity and transparency. PMID:23517275

Kim, Jongwook; Kang, Jonghyun; Jeong, Uiyoung; Kim, Heesuk; Lee, Hyunjung

2013-04-24

314

Transparent and conductive electrodes combining AZO and ATO thin films for enhanced light scattering and electrical performance  

NASA Astrophysics Data System (ADS)

Al:ZnO (AZO) and Sb:SnO2 (ATO) thin films have been deposited by DC sputtering on soda lime glass (SLG) substrates. The preparation conditions were adjusted to obtain transparent films with high conductivity for AZO and high texture for ATO. Then, the combination of AZO and ATO thin films has been tested to enhance the optical scattering and the electrical performance. The structure, morphology, optical, and electrical properties have been analyzed for SLG/AZO, SLG/ATO and SLG/ATO/AZO samples. The surface texture has been characterized optically by the haze parameters for transmittance and reflectance (HT and HR), which have been related to the root mean square roughness for each sample. Some increase of the electrical resistance is obtained for the AZO films deposited on rough ATO underlayers as compared with analogous AZO grown directly on the smooth SLG substrate. Nevertheless, ATO/AZO bilayers have allowed to achieve better electrical conductivity than ATO and greater optical scattering than isolated ATO or AZO films. In this way, average haze values of HT = 30% and HR = 72%, together with sheet resistance of 20 ?/sq. have been obtained by combining 150 nm-thick ATO and 800 nm-thick AZO films.

Guillén, C.; Montero, J.; Herrero, J.

2013-01-01

315

The Preparation and Properties of Al-Doped ZnO Thin Films as Transparent Electrodes for Solar Cell  

NASA Astrophysics Data System (ADS)

Transparent conductive oxides based on ZnO are promising materials for application in thin-film solar photovoltaic cells. Al-doped ZnO thin films with a large area of 1 m × 1.5 m were prepared by magnetic sputtering on glass substrate using a ceramic target (98 wt. % ZnO, 2 wt. % Al2O3) in different Ar+H2 ambient at different substrate temperature. SiO2 layer with a thickness of 20 nm was deposited as a resistant layer. To investigate the influence of H2-flow on the properties of AZO films, H2-flow rate was changed during the growth process with a fixed Ar-flow rate. The effect of the substrate temperature and the H2-flow rate on the structure, electrical and optical properties was studied. In order to enhance light scattering and absorption inside the cell, suitable surface texture is needed. The influence of wet chemical etching on surface roughness and haze of AZO were also investigated.

Ding, J. N.; Tan, C. B.; Yuan, N. Y.; Feng, X. W.; Chang, X. Y.; Ye, F.

316

Comparative studies of “all sol–gel” electrochromic devices with optically passive counter-electrode films, ormolyte Li + ion-conductor and WO 3 or Nb 2O 5 electrochromic films  

Microsoft Academic Search

Laminated electrochromic (EC) devices are becoming increasingly important for making “smart” windows and switchable displays. Mostly, polymeric Li+ ionic conductors in combination with vacuum deposited active electrochromic and counter-electrode films are used. In this paper we report on the development of all sol–gel EC devices, that is, those where all three internal layers are prepared via the sol–gel route, including

B. Orel; U. Opara Krašovec; M. Ma?ek; F. Švegl; U. Lavren?i? Štangar

1999-01-01

317

Transparent lithium-ion batteries.  

PubMed

Transparent devices have recently attracted substantial attention. Various applications have been demonstrated, including displays, touch screens, and solar cells; however, transparent batteries, a key component in fully integrated transparent devices, have not yet been reported. As battery electrode materials are not transparent and have to be thick enough to store energy, the traditional approach of using thin films for transparent devices is not suitable. Here we demonstrate a grid-structured electrode to solve this dilemma, which is fabricated by a microfluidics-assisted method. The feature dimension in the electrode is below the resolution limit of human eyes, and, thus, the electrode appears transparent. Moreover, by aligning multiple electrodes together, the amount of energy stored increases readily without sacrificing the transparency. This results in a battery with energy density of 10 Wh/L at a transparency of 60%. The device is also flexible, further broadening their potential applications. The transparent device configuration also allows in situ Raman study of fundamental electrochemical reactions in batteries. PMID:21788483

Yang, Yuan; Jeong, Sangmoo; Hu, Liangbing; Wu, Hui; Lee, Seok Woo; Cui, Yi

2011-08-01

318

Low-temperature synthesis of indium tin oxide nanowires as the transparent electrodes for organic light emitting devices.  

PubMed

Low-temperature growth of indium tin oxide (ITO) nanowires (NWs) was obtained on catalyst-free amorphous glass substrates at 250?°C by Nd:YAG pulsed-laser deposition. These ITO NWs have branching morphology as grown in Ar ambient. As suggested by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), our ITO NWs have the tendency to grow vertically outward from the substrate surface, with the (400) plane parallel to the longitudinal axis of the nanowires. These NWs are low in electrical resistivity (1.6×10?? ? cm) and high in visible transmittance (~90–96%), and were tested as the electrode for organic light emitting devices (OLEDs). An enhanced current density of ~30 mA cm?² was detected at bias voltages of ~19–21 V with uniform and bright emission. We found that the Hall mobility of these NWs is 2.2–2.7 times higher than that of ITO film, which can be explained by the reduction of Coulomb scattering loss. These results suggested that ITO nanowires are promising for applications in optoelectronic devices including OLED, touch screen displays, and photovoltaic solar cells. PMID:22166812

Kee, Yeh Yee; Tan, Sek Sean; Yong, Thian Khok; Nee, Chen Hon; Yap, Seong Shan; Tou, Teck Yong; Sáfrán, György; Horváth, Zsolt Endre; Moscatello, Jason P; Yap, Yoke Khin

2012-01-20

319

Optical-to-optical interface device. [consisting of two transparent electrodes on glass substrates that enclose thin film photoconductor and thin layer of nematic liquid crystal  

NASA Technical Reports Server (NTRS)

Studies were conducted on the performance of a photoactivated dc liquid crystal light valve. The dc light valve is a thin film device that consists of two transparent electrodes, deposited on glass substrates, that enclose a thin film photoconductor (cadmium sulfide) and a thin layer of a nematic liquid crystal that operates in the dynamic scattering mode. The work was directed toward application of the light valve to high resolution non-coherent light to coherent light image conversion. The goal of these studies was to improve the performance and quality of the already existing dc light valve device and to evaluate quantitatively the properties and performance of the device as they relate to the coherent optical data processing application. As a result of these efforts, device sensitivity was improved by a factor of ten, device resolution was improved by a factor of three, device lifetime was improved by two-orders of magnitude, undesirable secondary liquid crystal scattering effects were eliminated, the scattering characteristics of the liquid crystal were thoroughly documented, the cosmetic quality of the devices was dramatically improved, and the performance of the device was fully documented.

Jacobson, A. D.

1973-01-01

320

Design and fabrication of nanometric ZnS/Ag/MoO3 transparent conductive electrode and investigating the effect of annealing process on its characteristics  

NASA Astrophysics Data System (ADS)

In this paper, a ZnS/Ag/MoO3 (ZAM) nano-multilayer structure is designed theoretically and optimum thicknesses of each layer are calculated. ZnS/Ag/MoO3 multilayer films with optimized thicknesses have also been fabricated on glass substrates by thermal evaporation method at room temperature. The structural, electrical and optical properties of ZnS/Ag/MoO3 multilayer are investigated with respect to the variation of annealing temperature. X-ray diffraction patterns show that increase in annealing temperature increases the crystallinity of the structures. High-quality multilayer films with the sheet resistance of 4.5 ?/sq and the maximum optical transmittance of 85% at 100 °C annealing temperature are obtained. The allowed direct band gap for annealing at different temperatures is estimated to be in the range of 3.37-3.79 eV. The performance of the ZAM multilayer films are evaluated using a predefined figure of merit. These multilayer films can be used as transparent conductive electrodes in optoelectronic devices such as solar cells and organic light emitting diodes.

Kermani, Hamideh; Fallah, Hamid Reza; Hajimahmoodzadeh, Morteza

2013-01-01

321

Vertically aligned ZnO@CuS@PEDOT core@shell nanorod arrays decorated with MnO? nanoparticles for a high-performance and semi-transparent supercapacitor electrode.  

PubMed

Hybrid nano-architectures with high electrochemical performance for supercapacitors have been designed by growing hierarchical ZnO NRs@CuS@PEDOT@MnO2 core@shell heterostructured nanorod arrays on ITO/glass substrates. This hybrid nano-structured electrode exhibits excellent electrochemical performance, with a high specific areal capacitance of 19.85 mF cm(-2), good rate capability, cycling stability and diffused coloured transparency. PMID:24756158

Rodríguez-Moreno, Jorge; Navarrete-Astorga, Elena; Dalchiele, Enrique A; Schrebler, Ricardo; Ramos-Barrado, José R; Martín, Francisco

2014-05-30

322

Counting Counters  

NSDL National Science Digital Library

This problem gives children an opportunity to explore an increasing pattern and then generalize the results with a rule. Students begin with a single counter, surround it by a ring of other counters and then each new ring is surrounded with more counters. Solvers record results as they replicate the pattern and make predictions about many counters there will be in any given ring. The Teachers' Notes page offers suggestions for implementation, key discussion questions, ideas for extension and support.

2003-03-01

323

Effect of deposition temperature on the properties of Al-doped ZnO films prepared by pulsed DC magnetron sputtering for transparent electrodes in thin-film solar cells  

NASA Astrophysics Data System (ADS)

A simple but scalable approach to the production of surface-textured Al-doped ZnO(AZO) films for low-cost transparent electrode applications in thin-film solar cells is introduced in this study by combining pulsed dc magnetron sputtering (PDMS) with wet etching in sequence. First, structural, electrical, and optical properties of the AZO films prepared by a PDMS were investigated as functions of deposition temperature to obtain transparent electrode films that can be used as indium-free alternative to ITO electrodes. Increase in the deposition temperature to 230 °C accompanied the improvement in crystalline quality and doping efficiency, which enabled the lowest electrical resistivity of 4.16 × 10-4 ? cm with the carrier concentration of 1.65 × 1021 cm-3 and Hall mobility of 11.3 cm2/V s. The wet etching of the films in a diluted HCl solution resulted in surface roughening via the formation of crater-like structures without significant degradation in the electrical properties, which is responsible for the enhanced light scattering capability required for anti-reflective electrodes in thin film solar cells.

Kim, Doo-Soo; Park, Ji-Hyeon; Shin, Beom-Ki; Moon, Kyeong-Ju; Son, Myoungwoo; Ham, Moon-Ho; Lee, Woong; Myoung, Jae-Min

2012-10-01

324

Optimization of transparent and reflecting electrodes for amorphous-silicon solar cells. Final subcontract report, 1 May 1991--30 April 1994.  

National Technical Information Service (NTIS)

Fluorine-doped zinc oxide was shown to have the lowest absorption loss of any of the known transparent conductors. An apparatus was constructed to deposit textured, transparent, conductive, fluorine-doped zinc oxide layers with uniform thickness over a 10...

R. G. Gordon J. Hu D. Lacks J. Musher J. Thornton

1994-01-01

325

Factors determining the photovoltaic performance of a CdSe quantum dot sensitized solar cell: the role of the linker molecule and of the counter electrode  

NASA Astrophysics Data System (ADS)

Colloidal CdSe quantum dots (QDs) of different sizes, prepared by a solvothermal route, have been employed as sensitizers of nanostructured TiO2 electrode based solar cells. Three different bifunctional linker molecules have been used to attach colloidal QDs to the TiO2 surface: mercaptopropionic acid (MPA), thioglycolic acid (TGA), and cysteine. The linker molecule plays a determinant role in the solar cell performance, as illustrated by the fact that the incident photon to charge carrier generation efficiency (IPCE) could be improved by a factor of 5-6 by using cysteine with respect to MPA. The photovoltaic properties of QD sensitized electrodes have been characterized for both three-electrode and closed two-electrode solar cell configurations. For three-electrode measurement a maximum power conversion efficiency near 1% can be deduced, but this efficiency is halved in the closed cell configuration mainly due to the decrease of the fill factor (FF).

Mora-Seró, Iván; Giménez, Sixto; Moehl, Thomas; Fabregat-Santiago, Francisco; Lana-Villareal, Teresa; Gómez, Roberto; Bisquert, Juan

2008-10-01

326

Monitoring of morphology and physical properties of cultured cells using a micro camera and a quartz crystal with transparent indium tin oxide electrodes after injections of glutaraldehyde and trypsin.  

PubMed

For investigating the effects of chemical stimulation to cultured cells, we have developed a quartz crystal sensor system with a micro charge-coupled device (CCD) camera that enables microphotograph imaging simultaneously with quartz crystal measurement. Human hepatoma cell line (HepG2) cells were cultured on the quartz crystal through a collagen film. The electrode of the quartz crystal was made of indium tin oxide (ITO) transparent electrodes that enable to obtain a transparent mode photograph. Glutaraldehyde and trypsin were injected to the chamber of the cells, respectively. The response of the quartz crystal was monitored and microphotographs were recorded, and the resonance frequency and resonance resistance were analyzed with an F-R diagram that plotted the resonance frequency and resonance resistance. In the case of the glutaraldehyde injection, the cells responded in two steps that included the fast response of the cross-linking reaction and the successive internal change in the cells. In the case of the trypsin injection, the responses included two processes. In the first step, cell adhesion factors were cleaved and the cell structure became round, and in the next step, the cells were deposited on the quartz crystal surface and the surface of the cells was directly in contact with the quartz crystal surface. PMID:18706321

Kang, Hyen-Wook; Ida, Kazumi; Yamamoto, Yuji; Muramatsu, Hiroshi

2008-08-22

327

Optimization of transparent and reflecting electrodes for amorphous-silicon solar cells. Final subcontract report, 1 May 1991--30 April 1994  

SciTech Connect

Fluorine-doped zinc oxide was shown to have the lowest absorption loss of any of the known transparent conductors. An apparatus was constructed to deposit textured, transparent, conductive, fluorine-doped zinc oxide layers with uniform thickness over a 10 cm by 10 cm area, using inexpensive, high-productivity atmospheric pressure chemical vapor deposition. Amorphous silicon solar cells grown on these textured films show very high peak quantum efficiencies (over 90%). However, a significant contact resistance develops at the interface between the amorphous silicon and the zinc oxide. Transparent, conductive gallium-doped zinc oxide films were grown by APCVD at a low enough temperature (260{degree}C) to be deposited on amorphous silicon as a final conductive back contact to solar cells. A quantum-mechanical theory of bonding was developed and applied to some metal oxides; it forms a basis for understanding TCO structures and the stability of their interfaces with silicon.

Gordon, R.G.; Hu, J.; Lacks, D.; Musher, J.; Thornton, J.; Liang, H. [Harvard Univ., Cambridge, MA (United States)

1994-07-01

328

One-step preparation of mirror-like NiS nanosheets on ITO for the efficient counter electrode of dye-sensitized solar cells.  

PubMed

NiS nanosheets on ITO substrates were synthesized with in situ growth via a one-step hydrothermal route, and exhibited an efficiency of 7.08% which was comparable to the solar cell based on the Pt electrode (7.01%) under the similar conditions. PMID:25025947

Sun, Xun; Dou, Jie; Xie, Fengyan; Li, Yafeng; Wei, Mingdeng

2014-07-31

329

Two wireless imaging proportional counters  

NASA Astrophysics Data System (ADS)

Two wireless position-sensitive X-ray proportional counters that are being developed at the Danish Space Research Institute are described: the microstrip proportional counter (MSPC) and the parallel gas proportional counter (PGPC). The MSPC employs very narrowly spaced conducting strips deposited on an isolating substrate, thus avoiding the use of fragile wires. This detector is built like a normal axial ionization chamber with the electric field parallel to the direction of the incident radiation. The PGPC employs a uniform electric field between two parallel electrodes. The parallel gap is formed between an etched Ni mesh cathode and a segmented anode; the X-ray photon energy is derived from the mesh electrode, while the position information is obtained from the anode. Both detectors display energy signals of a very high rise-time and background rejection based on pulse shape analysis, and are, therefore, very efficient.

Budtz-Jorgensen, C.; Madsen, M. M.; Jonasson, P.; Westergaard, N. J.; Bahnsen, A.

1989-11-01

330

Counter Square  

NSDL National Science Digital Library

This interactive 100 grid has a variety of open-ended uses. Users can "make" as many counters as they choose from among three different kinds, and then drag them onto the grid, allowing any number to be covered by up to 3 different markers at one time. An Ideas page offers possible tasks and games suited to the applet.

2000-01-01

331

Calorie Counter  

MedlinePLUS

... articles window. My Saved Articles » My ACS » + - Text Size American Cancer Society Calorie Counter How many calories do you need to eat to maintain your current weight? This tool will give you an estimate. If you're trying to lose weight, see ...

332

Conductive and transparent multilayer films for low-temperature TiO2/Ag/SiO2 electrodes by E-beam evaporation with IAD.  

PubMed

Conductive and transparent multilayer thin films consisting of three alternating layers (TiO2/Ag/SiO2, TAS) have been fabricated for applications as transparent conducting oxides. Metal oxide and metal layers were prepared by electron-beam evaporation with ion-assisted deposition, and the optical and electrical properties of the resulting films as well as their energy bounding characteristics and microstructures were carefully investigated. The optical properties of the obtained TAS material were compared with those of well-known transparent metal oxide glasses such as ZnO/Ag/ZnO, TiO2/Ag/TiO2, ZnO/Cu/ZnO, and ZnO/Al/ZnO. The weathering resistance of the TAS film was improved by using a protective SiO2 film as the uppermost layer. The transmittance spectra and sheet resistance of the material were carefully measured and analyzed as a function of the layer thickness. By properly adjusting the thickness of the metal and dielectric films, a low sheet resistance of 6.5 ohm/sq and a high average transmittance of over 89% in the 400 to 700 nm wavelength regions were achieved. We found that the Ag layer played a significant role in determining the optical and electrical properties of this film. PMID:24433437

Chiu, Po-Kai; Lee, Chao-Te; Chiang, Donyau; Cho, Wen-Hao; Hsiao, Chien-Nan; Chen, Yi-Yan; Huang, Bo-Ming; Yang, Jer-Ren

2014-01-01

333

Perceptual transparency  

NASA Astrophysics Data System (ADS)

We suggest that color constancy and perceptual transparency might be explained by the same underlying mechanism. For color constancy, Foster and Nascimento (1994) found that cone-excitation ratios between surfaces seen under one illuminant and cone-excitation ratios between the same surfaces seen under a different illuminant were almost constant. In the case of perceptual transparency we also found that cone-excitation ratios between surfaces illuminated directly and cone-excitation ratios between the same surfaces seen through a transparent filter were almost invariant (Westland and Ripamonti, 2000). We compare the ability of the cone-excitation-ratio invariance model to predict perceptual transparency with an alternative model based on convergence in color space (D'Zmura et al., 1997). Psychophysical data are reported from experiments where by subjects were asked to select which of two stimuli represented a Mondrian image partially covered by a homogeneous transparent filter. One of the stimuli was generated from the convergence model and the other was a modified version of the first stimulus such that the cone- excitation ratios were perfectly invariant. Subjects consistently selected the invariant stimulus confirming our hypothesis that perception of transparency is predicted by the degree of deviation frm an invariant ratio for the cone excitations.

Ripamonti, Caterina; Westland, Stephen

2002-06-01

334

One-step synthesis of carbon nanosheets converted from a polycyclic compound and their direct use as transparent electrodes of ITO-free organic solar cells.  

PubMed

Through a catalyst- and transfer-free process, we fabricated indium tin oxide (ITO)-free organic solar cells (OSCs) using a carbon nanosheet (CNS) with properties similar to graphene. The morphological and electrical properties of the CNS derived from a polymer of intrinsic microporosity-1 (PIM-1), which is mainly composed of several aromatic hydrocarbons and cycloalkanes, can be easily controlled by adjusting the polymer concentration. The CNSs, which are prepared by simple spin-coating and heat-treatment on a quartz substrate, are directly used as the electrodes of ITO-free OSCs, showing a high efficiency of approximately 1.922% under 100 mW cm(-2) illumination and air mass 1.5 G conditions. This catalyst- and transfer-free approach is highly desirable for electrodes in organic electronics. PMID:24162657

Son, Su-Young; Noh, Yong-Jin; Bok, Changsuk; Lee, Sungho; Kim, Byoung Gak; Na, Seok-In; Joh, Han-Ik

2014-01-21

335

One-step synthesis of carbon nanosheets converted from a polycyclic compound and their direct use as transparent electrodes of ITO-free organic solar cells  

NASA Astrophysics Data System (ADS)

Through a catalyst- and transfer-free process, we fabricated indium tin oxide (ITO)-free organic solar cells (OSCs) using a carbon nanosheet (CNS) with properties similar to graphene. The morphological and electrical properties of the CNS derived from a polymer of intrinsic microporosity-1 (PIM-1), which is mainly composed of several aromatic hydrocarbons and cycloalkanes, can be easily controlled by adjusting the polymer concentration. The CNSs, which are prepared by simple spin-coating and heat-treatment on a quartz substrate, are directly used as the electrodes of ITO-free OSCs, showing a high efficiency of approximately 1.922% under 100 mW cm-2 illumination and air mass 1.5 G conditions. This catalyst- and transfer-free approach is highly desirable for electrodes in organic electronics.Through a catalyst- and transfer-free process, we fabricated indium tin oxide (ITO)-free organic solar cells (OSCs) using a carbon nanosheet (CNS) with properties similar to graphene. The morphological and electrical properties of the CNS derived from a polymer of intrinsic microporosity-1 (PIM-1), which is mainly composed of several aromatic hydrocarbons and cycloalkanes, can be easily controlled by adjusting the polymer concentration. The CNSs, which are prepared by simple spin-coating and heat-treatment on a quartz substrate, are directly used as the electrodes of ITO-free OSCs, showing a high efficiency of approximately 1.922% under 100 mW cm-2 illumination and air mass 1.5 G conditions. This catalyst- and transfer-free approach is highly desirable for electrodes in organic electronics. Electronic supplementary information (ESI) available: Detailed experimental methods; chemical structure and 1H NMR spectra; AFM images; TGA spectra; shunt and series resistances; Raman spectra and optical images; atomic contents of the CNSs. See DOI: 10.1039/c3nr04828d

Son, Su-Young; Noh, Yong-Jin; Bok, Changsuk; Lee, Sungho; Kim, Byoung Gak; Na, Seok-In; Joh, Han-Ik

2013-12-01

336

Spray deposition of water-soluble multiwall carbon nanotube and Cu2ZnSnSe4 nanoparticle composites as highly efficient counter electrodes in a quantum dot-sensitized solar cell system.  

PubMed

In this paper, low-cost counter electrodes (CEs) based on water-soluble multiwall carbon nanotube (MWCNT) and Cu2ZnSnSe4 nanoparticle (CZTSe NP) composites have been successfully introduced into a quantum dot-sensitized solar cell (QDSC) system. Suitable surface modification allows the MWCNTs and CZTSe NPs to be homogeneously dispersed in water, facilitating the subsequent low-temperature spray deposition of high quality composite films with different composite ratios. The electrochemical catalytic activity of the composite CEs has been critically compared by electrochemical impedance spectroscopy and Tafel-polarization analysis. It is found that the composite CE at the MWCNT : CZTSe ratio of 0.1 offers the best performance, leading to an optimal solar cell efficiency of 4.60%, which is 50.8% higher than that of the Pt reference CE. The as-demonstrated higher catalytic activity of the composite CEs compared to their single components could be ascribed to the combination of the fast electron transport of the MWCNTs and the high catalytic activity of CZTSe NPs. PMID:23800939

Zeng, Xianwei; Xiong, Dehua; Zhang, Wenjun; Ming, Liqun; Xu, Zhen; Huang, Zhanfeng; Wang, Mingkui; Chen, Wei; Cheng, Yi-Bing

2013-08-01

337

Transparent Research.  

ERIC Educational Resources Information Center

Defines transparent research as a strategy in which the subjects of the research are fully involved in the entire process. Presents case studies of the emergency medical department of a medium-sized hospital and of a congregational development project developed in partnership with an Episcopal diocese. (JOW)

Milofsky, Carl

2000-01-01

338

Welcoming Transparency  

PubMed Central

In this column, the editor of The Journal of Perinatal Education (JPE) discusses why there is a need for transparency to improve maternity care. The editor also describes the contents of this JPE issue, which offer a broad range of resources, research, and inspiration for childbirth educators in their efforts to promote normal birth.

Budin, Wendy C.

2009-01-01

339

Transparent Electronically Controlled DNA Chips 1  

Microsoft Academic Search

A new electronically controlled DNA chip that consists of a glass substrate and indium tin oxide electrodes (ITO) has been developed. The glass substrate with ITO electrodes makes the chip transparent and enables detection of hybridization from below the surface of the chip via a CCD array which allows simplified detection optics and, possibly, improved sensitivity. ITO, however, is not

Gregory A. Miller; Yuri Y. Belosludtsev; Tiffany H. Murphy; Harold R. Garner

2000-01-01

340

Optimization of transparent and reflecting electrodes for amorphous silicon solar cells. Annual subcontract report, 1 May 1991--30 April 1992  

SciTech Connect

This report describes work to improve the performance of solar cells by improving the electrical and optical properties of their transparent conducting oxides (TCO) layers. Boron-doped zinc-oxide films were deposited by atmospheric pressure chemical vapor deposition in a laminar-flow reactor from diethyl zinc, tert-butanol, and diborane in the temperature range between 300{degrees}C and 420{degrees}C. When the deposition temperature was above 320{degrees}C, both doped and undoped films have highly oriented crystallites with their c-axes perpendicular to the substrate plane. Films deposited from 0.07% diethyl zinc and 2.4% tert-butanol have electron densities between 3.5 {times} 10{sup 20} cm{sup {minus}3} and 5.5 {times} 10{sup 20} cm{sup {minus}3}, conductivities between 250 {Omega}{sup {minus}1} and 2500 {Omega}{sup {minus}1} and mobilities between 2.5 cm{sup 2}/V-s and 35.0 cm{sup 2}/V-s, depending on dopant concentration, film thickness, and deposition temperature. Optical measurements show that the maximum infrared reflectance of the doped films is close to 90%, compared to about 20% for undoped films. Film visible absorption and film conductivity were found to increase with film thickness. The ratio of conductivity to visible absorption coefficient for doped films was between 0.1 {Omega} and 1.1 {Omega}{sup {minus}1}. The band gap of the film changes from 3.3 eV to 3.7 eV when the film is doped with 0.012% diborane.

Gordon, R.G. [Harvard Univ., Cambridge, MA (United States). Dept. of Chemistry

1993-04-01

341

Transparency International  

NSDL National Science Digital Library

Transparency International (TI) is a non-governmental organization concerned with "increasing governmental accountability and curbing both international and national corruption." Best known for its Corruption Perceptions Index (see the February 26, 1998 Scout Report for Business and Economics), Transparency International also offers a host of other corruption-related resources, including the TI Bribers's Pay Survey and TI Bribers's Pay Index, two resources on bribe-paying in international trade; an anti-corruption directory which serves as a reference guide to efforts in central and eastern European countries to support anti-corruption programs; working papers; and other publications. Also worthy of note is TI's ten-point program directed at pressuring the World Bank Organization to help strengthen its anti-corruption programs. The layout of the TI Website is somewhat confusing, but most of the organization's research efforts can be found in the Info Centre.

342

Composite Films Based on Poly(3,4-ethylene dioxythiophene):Poly(styrene sulfonate) Conducting Polymer and TiC Nanoparticles as the Counter Electrodes for Flexible Dye-Sensitized Solar Cells  

NASA Astrophysics Data System (ADS)

A composite film of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and titanium carbide nanoparticles (TiC-NPs) was deposited on an indium doped tin oxide--poly(ethylene naphthalate) (ITO--PEN) conducting plastic substrate by a doctor blade technique. This ITO--PEN substrate with the composite film was used as the flexible counter electrode (CE) for a plastic dye-sensitized solar cell (DSSC). Performances of the plastic DSSC with the platinum-free CEs containing PEDOT:PSS/TiC-NPs composite was investigated. A solar-to-electricity conversion efficiency (?) of 6.50% was achieved for the pertinent DSSC with PEDOT:PSS/TiC-NPs composite, using commercial N719 dye, which exhibited comparable performance to that of a cell with a sputtered-Pt film on its CE (6.84%). The homogeneous nature of the composite film PEDOT:PSS/TiC-NPs, the uniform distribution of TiC-NPs in its PEDOT:PSS matrix, and the large electrochemical surface area of the composite film are seen to be the factors for the best performance of the pertinent DSSC. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to characterize the TiC-NPs. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy dispersive X-ray spectroscopy (EDX) were used to characterize the films. The high efficiency of the cell with PEDOT:PSS/TiC-NPs is explained by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and incident photon-to-current conversion efficiency (IPCE) curves.

Yeh, Min-Hsin; Lin, Lu-Yin; Li, Yu-Yan; Chang, Jeffrey; Chen, Ping-Wei; Lee, Chuan-Pei; Ho, Kuo-Chuan

2012-10-01

343

Metal substrate based electrodes for flexible dye-sensitized solar cells: fabrication methods, progress and challenges.  

PubMed

A step towards commercialization of dye-sensitized solar cells (DSSCs) requires more attention to engineering aspects, such as flexibility, the roll to roll fabrication process, the use of cost effective materials, etc. In this aspect, advantages of flexible DSSCs attracted many researchers to contemplate the transparent conducting oxide coated flexible plastic substrates and the thin metallic foils. In this feature article, the pros and cons of these two kinds of substrates are compared. The flexible dye-sensitized solar cells fabricated using metal substrates are briefly discussed. The working electrodes of DSSCs fabricated on various metal substrates, their fabrication methods, the effect of high temperature calcination and drawbacks of back illumination are reviewed in detail. A few reports on the flexible metal substrate based counter electrodes that could be combined with the plastic substrate based working electrodes are also covered at the end. PMID:24196211

Balasingam, Suresh Kannan; Kang, Man Gu; Jun, Yongseok

2013-12-21

344

Electrowetting on flexible, transparent and conducting single-layer graphene  

Microsoft Academic Search

This paper reports the results of using graphene as a novel electrode material in the experiment of electrowetting on dielectric (EWOD). The device has a Teflon layer coated CVD graphene electrode which is patterned on transparent and flexible substrates such as PET films. By applying a potential difference between a liquid droplet and a graphene electrode, we observed a change

X. B. Tan; J. Yang; P. Zeng; E. G. R. Kim; C. Huard; M. M. C. Cheng

2012-01-01

345

Distributed performance counters  

DOEpatents

A plurality of first performance counter modules is coupled to a plurality of processing cores. The plurality of first performance counter modules is operable to collect performance data associated with the plurality of processing cores respectively. A plurality of second performance counter modules are coupled to a plurality of L2 cache units, and the plurality of second performance counter modules are operable to collect performance data associated with the plurality of L2 cache units respectively. A central performance counter module may be operable to coordinate counter data from the plurality of first performance counter modules and the plurality of second performance modules, the a central performance counter module, the plurality of first performance counter modules, and the plurality of second performance counter modules connected by a daisy chain connection.

Davis, Kristan D; Evans, Kahn C; Gara, Alan; Satterfield, David L

2013-11-26

346

Optimization of Nb{sub 2}O{sub 5}/Ag/Nb{sub 2}O{sub 5} multilayers as transparent composite electrode on flexible substrate with high figure of merit  

SciTech Connect

Different multilayer structures of Nb{sub 2}O{sub 5}/Ag/Nb{sub 2}O{sub 5} have been deposited onto flexible substrates by sputtering at room temperature to develop an indium free transparent composite electrode. The effect of Ag thickness on the electrical and optical properties of the multilayer stack has been studied in accordance with the Ag morphology. The critical thickness of Ag to form a continuous conducting layer is found to be 9.5 nm. A new conduction mechanism has been proposed to describe the conduction before and after the critical thickness. The effective Hall resistivity of the optimized films is as low as 6.44 Multiplication-Sign 10{sup -5} Ohm-Sign -cm with a carrier concentration and mobility of 7.4 Multiplication-Sign 10{sup 21} cm{sup -3} and 13.1 cm{sup 2} /V-s, respectively, at the critical Ag layer thickness. The multilayer stack has been optimized to obtain a sheet resistance of 7.2 Ohm-Sign /sq and an average optical transmittance of 86% at 550 nm without any substrate heating or post-annealing process. The Haacke figure of merit (FOM) has been calculated for the films, and the multilayer with a 9.5 nm thick Ag layer has the highest FOM at 31.5 Multiplication-Sign 10-3 {Omega}{sup -1}, which is one of the highest FOM values reported for TCE deposited at room temperature on a flexible substrate.

Dhar, Aritra [Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287 (United States); Alford, T. L. [School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287 (United States)

2012-11-15

347

Neutron Detection by Corrugated-Plate Spark Counters  

Microsoft Academic Search

Corrugated plates as spark counter electrodes provide well-defined discharge gaps with low operating voltages, analogous to the conditions more usually obtained in multiwire arrays. By inserting boric acid or a hydrogenous material into the grooves, sensitivity to thermal or fast neutrons may be obtained. For a more sensitive counter geometry, plastic strips have been mounted between the grooves of adjoining

G. G. Eichholz; W. M. Templeton

1966-01-01

348

Time resolution of a large area planar spark counter  

Microsoft Academic Search

A planar spark counter of size 1.0 m × 0.1 m has been developed and tested. The constituent elements are a semiconductive glass anode and a window float-cast glass cathode coated by vacuum-deposited copper. The distance between electrodes is 200 mum. A single counter time resolution of 61 ps was achieved with cosmic rays.

Noboru Fujiwara; Naoko Iida; Seishi Noguchi; Ryuhei Sugahara; Tsuyoshi Suwada; Taro Ohama; Kasuke Takahashi

1988-01-01

349

Transparent screens.  

PubMed

There is a kind of transitional phenomenon found among certain borderline patients which is quite distinct from Winnicott's transitional object. These are patients who are preoccupied with maintaining proper physical distance from their objects, in order to regulate anxieties about isolation on the one hand, and identity-annihilating closeness on the other. Since they believe the activity of looking to be intrusive and devouring, hence dangerous, transparent screens are interposed between self and other, and serve as protective barriers. These screens function intrapsychically as well, to split off or hide those aspects of the self felt to be unacceptable. The analyst may witness the failure of the screen in several ways: it may create too great a distance, isolating the individual and keeping him from life; it may become contaminated by projections and turn into a persecutor, or trap the individual, a state of intolerable claustrophobia; most dramatically, it may suddenly shatter. The latter is associated with psychosis and death, and its appearance may be a harbinger of suicide. PMID:3403907

Rosenthal, R J

1988-01-01

350

Transparent switchboard  

NASA Technical Reports Server (NTRS)

A tin oxide coating is formed on a plate of glass and the coating is then etched away from the glass in thin lines to form separate electrical conductors which extend to one end of the plate and connect to either a vertical (column) or horizontal (row) position sensing SCR circuit. A thin transparent insulating coating is formed over the oxide layer except at selected touch points which are positioned in a matrix pattern of vertical columns and horizontal rows. Touching one of these points with a finger bridges the thin line between adjacent conductors to activate trigger circuits in the particular row and column sensing circuits associated with the point touched. The row and column sensing circuits are similar and are powered with a low frequency, ac voltage source. The source for the row circuits is 180 out of phase with the source for the column circuits so that one circuit acts as ground for the other during half of the supply voltage cycle. The signals from the sensing circuits are input to a logic circuit which determines the presence of a valid touch, stores a binary matrix number associated with the touched point, signals a computer of the presence of a stored number and prevents storage of a new number before receiving an enable signal from the computer.

Rasmussen, H. P. (inventor)

1973-01-01

351

Zinc-indium-oxide: A high conductivity transparent conducting oxide  

Microsoft Academic Search

We report the fabrication and characterization of zinc-indium-oxide films with similar electrical conductivity and better transparency in both the visible and infrared compared with indium–tin–oxide, a widely used transparent conductor in many technological applications. Dramatically superior transmission properties in the 1–1.5 ?m range in particular make zinc–indium–oxide attractive for use in infrared devices, where transparent electrodes are required. Resisitivities as

Julia M. Phillips; R. J. Cava; G. A. Thomas; S. A. Carter; J. Kwo; T. Siegrist; J. J. Krajewski; J. H. Marshall; W. F. Peck Jr.; D. H. Rapkine

1995-01-01

352

Optically transparent piezoelectric transducer for ultrasonic particle manipulation.  

PubMed

We report an optically transparent ultrasonic device, consisting of indium-tin-oxide-coated lithium niobate (LNO), for use in particle manipulation. This device shows good transparency in the visible and near-infrared wavelengths and, acoustically, compares favorably with conventional prototype devices with silver electrodes. PMID:24569243

Brodie, Graham W J; Qiu, Yongqiang; Cochran, Sandy; Spalding, Gabriel C; MacDonald, Michael P

2014-03-01

353

Doped graphene electrodes for organic solar cells  

Microsoft Academic Search

In this work graphene sheets grown by chemical vapor deposition (CVD) with controlled numbers of layers were used as transparent electrodes in organic photovoltaic (OPV) devices. It was found that for devices with pristine graphene electrodes, the power conversion efficiency (PCE) is comparable to their counterparts with indium tin oxide (ITO) electrodes. Nevertheless, the chances for failure in OPVs with

Jill A. Rowehl; Ki Kang Kim; Vladimir Bulovic; Jing Kong

2010-01-01

354

The parallel plate avalanche counter: a simple, rugged, imaging X-ray counter  

Microsoft Academic Search

A two-dimensional parallel gap proportional counter has been developed at the Danish Space Research Institute. Imaging over the 120 mm diameter active area is obtained using the positive ion component of the avalanche signals as recorded by a system of wedge- and strip-electrodes. An electronically simple, but very effective background rejection is obtained by using the fast electron component of

K. D. Joensen; C. Budtz-Jørgensen; A. Bahnsen; M. M. Madsen; C. Olesen; H. W. Schnopper

1995-01-01

355

Transparent flexible resistive random access memory fabricated at room temperature  

NASA Astrophysics Data System (ADS)

We report the room temperature fabrication of highly transparent and flexible resistive random access memory devices based on an ITO (indium tin oxide)/ZnO (zinc oxide)/ITO/Ag/ITO capacitor structure on a polyethersulfone flexible substrate. The ITO/Ag/ITO multilayered bottom electrode provides superior flexibility as well as high transparency compared to devices with ITO single bottom electrode during repetitive bending tests. The devices exhibit a high transmittance and the excellent reliability of data retention. Moreover, they show consistent memory performance, even under thermal stress. The results of this study provide a breakthrough solution for the era of transparent and flexible electronic systems in the near future.

Won Seo, Jung; Park, Jae-Woo; Lim, Keong Su; Kang, Sang Jung; Hong, Yun Ho; Yang, Ji Hwan; Fang, Liang; Sung, Gun Yong; Kim, Han-Ki

2009-09-01

356

TickCounter  

NSDL National Science Digital Library

Would you like to countdown? Or count up? Well then TickCounter might be worth checking out. TickCounter lets users create their own countdown clock so that they can keep tabs on important events and dates. Visitors can customize the clock for the time zone of their choice, and they can also give each event or date a name for easy reference. TickCounter is compatible with all operating systems.

2011-01-01

357

Growth and characterization of transparent conducting nanostructured zinc indium oxide thin films  

Microsoft Academic Search

Transparent conductive oxide (TCO) films have been widely used in various applications, such as for transparent electrodes in flat-panel displays, and in solar cells, optoelectronic devices, touch panels and IR reflectors. Among these, tin doped zinc oxide (ZTO) and indium doped zinc oxide (ZIO) have attracted considerable attention. Particularly, IZO thin film is the best candidate for high-quality transparent conducting

Vipin Kumar Jain; Praveen Kumar; Deepika Bhandari; Y. K. Vijay

2010-01-01

358

Electromagnetically Induced Transparency.  

National Technical Information Service (NTIS)

We report the first observation of electromagnetically induced transparency in optically thick medium. The transparency results from a destructive interference of two dressed states which are created by applying a temporally smooth coupling laser between ...

A. Imamoglu K. J. Boiler S. E. Harris

1992-01-01

359

Superhard Transparent Coatings.  

National Technical Information Service (NTIS)

The purpose of this work is to develop and provide a superhard coating (Moh hardness > 5) which is transparent and which will adhere to various polymeric sheet substrates. This coating is to protect helicopter transparencies from scratching and objectiona...

A. M. Marks

1975-01-01

360

An Improved Electron Multiplier Particle Counter  

Microsoft Academic Search

The design and construction of a 13-stage electron multiplier tube are discussed. Electrodes formed from BeCu alloy sheet are used and the method of activating these surfaces is described. The over-all multiplication of this type of tube is about 107. The efficiency of the tube as an electron counter is 100 percent for electrons of 500 ev and decreases to

James S. Allen

1947-01-01

361

The Opacity of Transparency  

Microsoft Academic Search

The normative concept of transparency, along with the open government laws that purport to create a transparent public system of governance promise the world—a democratic and accountable state above all, and a peaceful, prosperous, and efficient one as well. But transparency, in its role as the theoretical justification for a set of legal commands, frustrates all parties affected by its

Mark Fenster

2005-01-01

362

The Opacity of Transparency  

Microsoft Academic Search

The normative concept of transparency, along with the open government laws that purport to create a transparent public system of governance, promises the moon -- a democratic and accountable state above all, and a peaceful, prosperous, and efficient one as well. But transparency, in its role as the theoretical justification for a set of legal commands, frustrates all parties affected

Mark Fenster

2006-01-01

363

Transparent, flexible supercapacitors from nano-engineered carbon films  

PubMed Central

Here we construct mechanically flexible and optically transparent thin film solid state supercapacitors by assembling nano-engineered carbon electrodes, prepared in porous templates, with morphology of interconnected arrays of complex shapes and porosity. The highly textured graphitic films act as electrode and current collector and integrated with solid polymer electrolyte, function as thin film supercapacitors. The nanostructured electrode morphology and the conformal electrolyte packaging provide enough energy and power density for the devices in addition to excellent mechanical flexibility and optical transparency, making it a unique design in various power delivery applications.

Jung, Hyun Young; Karimi, Majid B.; Hahm, Myung Gwan; Ajayan, Pulickel M.; Jung, Yung Joon

2012-01-01

364

An Inexpensive Radiation Counter.  

ERIC Educational Resources Information Center

Describes a radiation counter comparable to commercial units which costs less than $100. It consists of six sections: Geiger-Mueller tube and holder; high voltage supply; low voltage supply; pulse shaping circuit; "start/stop counts" gating circuit; and counter/display. List of materials needed and schematic diagrams are included. (JN)

Holton, Brian; Balla, Zsolt

1985-01-01

365

Pyrochemical multiplicity counter development  

SciTech Connect

Impure plutonium-bearing materials from pyrochemical processes often display both significant self-multiplication and variable ({alpha},n) reaction rates. Standard neutron coincidence counting techniques usually fail to accurately measure these materials. Neutron multiplicity counters measure the third moment of the neutron multiplicity distribution and thus make it possible to deduce the fertile plutonium mass of a sample even when both the self-multiplication and the ({alpha},n) reaction rate are unknown. A multiplicity counter suitable for measuring pyrochemical materials has been designed and built. This paper describes the results of characterization studies for the new counter. The counter consists of 126 helium-3 tubes arranged in 4 concentric rings in a polyethylene moderator; the average spacing between the tubes is 1.59 cm. The end plugs for the counter are made of graphite, and the 24.1- by 37.5-cm sample cavity is cadmium lined. The counter consists of two distinct halves from which the neutron counts are summed. The counter is capable of operation in either a freestanding mode with the two halves coupled together by an external cabinet or in a glove-box mode with the two halves placed around a glovebox well and then mated. For a {sup 252}Cf source centered in the sample cavity, the measured efficiency of the new multiplicity counter is 57.7% and its die-away time is 47.2{mu}s. 8 refs., 9 figs.

Langner, D.G.; Dytlewski, N.; Krick, M.S.

1991-01-01

366

Slow-light dispersion by transparent waveguide plasmon polaritons  

NASA Astrophysics Data System (ADS)

We propose a classical analogue of electromagnetically induced transparency for a two-level ensemble interacting with two orthogonal optical modes. We show that a single localized plasmon resonance of a metal nanoparticle ensemble coupled to counter-propagating modes of a dielectric waveguide generates a slow transparent waveguide-plasmon polariton. Dispersion is controllable by tuning the coupling strengths of localized plasmon and waveguide modes, while maintaining extremely low loss at the system's transparency. Strong coupling in such plasmonic hybrid systems leads to large group index-bandwidth products.

Ishikawa, Atsushi; Oulton, Rupert F.; Zentgraf, Thomas; Zhang, Xiang

2012-04-01

367

Terahertz transparency of optically opaque metallic films  

NASA Astrophysics Data System (ADS)

Here we present an alternative approach to design a freestanding transparent conducting device for wide-angle and polarization-insensitive incidence of electromagnetic waves at terahertz frequencies. It is realized by depositing periodic metallic patches on top and bottom of the subwavelength metallic mesh. Based on the numerical computations, the deposited metallic patches can suppress the reflection and enhance the transmission. The high transmission of the designed system is attributed to the impedance matching to the vacuum. This design of a transparent conducting device can be useful in applications, such as optoelectronic electrodes and micro-electronic displays, where both high electrical conductivity and high optical transmittance are desirable.

Song, Zhengyong; Gao, Zhen; Zhang, Youming; Zhang, Baile

2014-04-01

368

Thickness-self-controlled synthesis of porous transparent polyaniline-reduced graphene oxide composites towards advanced bifacial dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

A powerful synthesis strategy is proposed for fabricating porous polyaniline-reduced graphene oxide (PANI-RGO) composites with transparency up to 80% and thickness from 300 to 1000 nm for the counter electrode (CE) of bifacial dye-sensitizing solar cells (DSSCs). The first step is to combine the in-situ positive charge transformation of graphene oxide (GO) through aniline (ANI) prepolymerization and the electrostatic adsorption of ANI oligomer-GO to effectively control the thickness of ultrathin PANI-GO films by adjusting pH of the polymerization media. In the second step, PANI-GO films are reduced with hydroiodic acid to simultaneously enhance the apparent redox activity for the I3-/I- couple and their electronic conductivity. Incorporating the RGO increases the transparency of PANI and facilitates the light-harvesting from the rear side. A DSSC assembled with such a transparent PANI-RGO CE exhibits an excellent efficiency of 7.84%, comparable to 8.19% for a semi-transparent Pt-based DSSC. The high light-harvesting ability of PANI-RGO enhances the efficiency retention between rear- and front-illumination modes to 76.7%, compared with 69.1% for a PANI-based DSSC. The higher retention reduces the power-to-weight ratio and the total cost of bifacial DSSCs, which is also promising in other applications, such as windows, power generators, and panel screens.

Wang, Yu-Sheng; Li, Shin-Ming; Hsiao, Sheng-Tsung; Liao, Wei-Hao; Yang, Shin-Yi; Tien, Hsi-Wen; Ma, Chen-Chi M.; Hu, Chi-Chang

369

Development of a High-Rate Ionization Counter  

NASA Astrophysics Data System (ADS)

Ionization counters are useful for the determination of beam composition and beam normalization in many nuclear physics experiments. At the Holifield Radioactive Ion Beam Facility (HRIBF), we have developed and are currently testing a new ionization counter that will count and accurately identify particles at rates up to 10^6 pps. The new ion counter is based on the tilted electrode gas ion chamber (TEGIC) model developed at RIKEN [1] and consists of alternating anodes and cathodes, effectively creating a stack of ion chambers. Design and results from preliminary testing will be presented. [4pt] [1] Kimura et al., Nucl. Instr. And Methods A 538 608 (2005).

Strauss, Sabrina; Bardayan, D. W.; Chae, K. Y.; Cizewski, J. A.; Peters, W. A.; Schmitt, K. T.; Smith, M. S.

2010-11-01

370

Portable multiplicity counter  

DOEpatents

A portable multiplicity counter has signal input circuitry, processing circuitry and a user/computer interface disposed in a housing. The processing circuitry, which can comprise a microcontroller integrated circuit operably coupled to shift register circuitry implemented in a field programmable gate array, is configured to be operable via the user/computer interface to count input signal pluses receivable at said signal input circuitry and record time correlations thereof in a total counting mode, coincidence counting mode and/or a multiplicity counting mode. The user/computer interface can be for example an LCD display/keypad and/or a USB interface. The counter can include a battery pack for powering the counter and low/high voltage power supplies for biasing external detectors so that the counter can be configured as a hand-held device for counting neutron events.

Newell, Matthew R. (Los Alamos, NM) [Los Alamos, NM; Jones, David Carl (Los Alamos, NM) [Los Alamos, NM

2009-09-01

371

Neutron multiplicity counter development  

SciTech Connect

We have designed and built two multiplicity counters to test the usefulness of multiplicity counting for the safeguards assay of plutonium-bearing materials. The first prototype counter has been characterized and a variety of plutonium-bearing materials have been measured with it. Assays accurate to {approximately}0.7% have been obtained for both pure and impure plutonium oxide samples in reasonable measurement times. Assays accurate to {approximately}5% have been obtained for metal samples. A second multiplicity counter has been designed using experience gained from the first as well as Monte Carlo simulations. The second counter was designed to be more suitable for in-plant measurement of pyrochemical process materials. This paper presents the results of characterization studies of the two instruments. 10 refs., 9 figs., 2 tabs.

Langner, D.G.; Krick, M.S.; Ensslin, N.; Bosler, G.E.; Dytlewski, N.

1991-01-01

372

Conditions for perceptual transparency  

NASA Astrophysics Data System (ADS)

We review the conditions that are necessary for the perception of transparency and describe the spatiochromatic constraints for achromatic and chromatic transparent displays. These constraints can be represented by the convergence model and are supported by psychophysical data. We present an alternative representation of the constraints necessary for transparency perception that is based on an analogy with a model of colour constancy and the invariance of cone-excitation ratios. Recent psychophysical experiments are described that suggest that displays where the cone-excitation ratios are invariant produce a stronger impression of transparency than displays where the cone excitations are convergent. We argue that the spatial relations in an image are preserved when a Mondrian-like surface is partially covered by a transparent filter and therefore show an intriguing link between transparency perception and colour constancy. Finally, we describe experiments to relate the strength of the transparency percept with the number of unique patches in the image display. We find that the greater the number of surfaces in the display that are partially covered by a transparent filter the stronger the impression of transparency.

Westland, Stephen; da Pos, Osvaldo; Ripamonti, Caterina

2002-06-01

373

Optomechanically induced transparency.  

PubMed

Electromagnetically induced transparency is a quantum interference effect observed in atoms and molecules, in which the optical response of an atomic medium is controlled by an electromagnetic field. We demonstrated a form of induced transparency enabled by radiation-pressure coupling of an optical and a mechanical mode. A control optical beam tuned to a sideband transition of a micro-optomechanical system leads to destructive interference for the excitation of an intracavity probe field, inducing a tunable transparency window for the probe beam. Optomechanically induced transparency may be used for slowing and on-chip storage of light pulses via microfabricated optomechanical arrays. PMID:21071628

Weis, Stefan; Rivière, Rémi; Deléglise, Samuel; Gavartin, Emanuel; Arcizet, Olivier; Schliesser, Albert; Kippenberg, Tobias J

2010-12-10

374

Silver nanowire-based transparent, flexible, and conductive thin film  

PubMed Central

The fabrication of transparent, conductive, and uniform silver nanowire films using the scalable rod-coating technique is described in this study. Properties of the transparent conductive thin films are investigated, as well as the approaches to improve the performance of transparent silver nanowire electrodes. It is found that silver nanowires are oxidized during the coating process. Incubation in hydrogen chloride (HCl) vapor can eliminate oxidized surface, and consequently, reduce largely the resistivity of silver nanowire thin films. After HCl treatment, 175 ?/sq and approximately 75% transmittance are achieved. The sheet resistivity drops remarkably with the rise of the film thickness or with the decrease of transparency. The thin film electrodes also demonstrated excellent flexible stability, showing < 2% resistance change after over 100 bending cycles.

2011-01-01

375

Control of edge effects of oxidant electrode  

DOEpatents

Described is an electrode assembly comprising; a. a porous electrode having a first and second exterior face with a cavity formed in the interior between said exterior faces thereby having first and second interior faces positioned opposite the first and second exterior faces; b. a counter electrode positioned facing each of the first and second exterior faces of the porous electrode; c. means for passing an oxidant through said porous electrode; and d. screening means for blocking the interior face of the porous electrode a greater amount than the blocking of the respective exterior face of the porous electrode, thereby maintaining a differential of oxidant electrode surface between the interior face and the exterior face. The electrode assembly is useful in a metal, halogen, halogen hydrate electrical energy storage device.

Carr, Peter (Utica, MI); Chi, Chen H. (Sterling Heights, MI)

1981-09-08

376

Zinc Oxide Transparent Thin Films For Optoelectronics  

NASA Astrophysics Data System (ADS)

The object of this body of work is to study the properties and suitability of zinc oxide thin films with a view to engineering them for optoelectronics applications, making them a cheap and effective alternative to indium tin oxide (ITO), the most used transparent conducting oxides in the industry. Initially, a study was undertaken to examine the behavior of silver contacts to ZnO and ITO during thermal processing, a step frequently used in materials processing in optoelectronics. The second study involved an attempt to improve the conductivity of ZnO films by inserting a thin copper layer between two ZnO layers. The Hall resistivity of the films was as low as 6.9x10 -5 O-cm with a carrier concentration of 1.2x10 22 cm-3 at the optimum copper layer thickness. The physics of conduction in the films has been examined. In order to improve the average visible transmittance, we replaced the copper layer with gold. The films were then found to undergo a seven orders of magnitude drop in effective resistivity from 200 O-cm to 5.2x10-5 O-cm The films have an average transmittance between 75% and 85% depending upon the gold thickness, and a peak transmittance of up to 93%. The best Haacke figure of merit was 15.1x10-3 O-1. Finally, to test the multilayer transparent electrodes on a device, ZnO/Au/ZnO (ZAZ) electrodes were evaluated as transparent electrodes for organic light-emitting devices (OLEDs). The electrodes exhibited substantially enhanced conductivity (about 8x10-5 O-cm) over conventional indium tin oxide (ITO) electrodes (about 3.2x10-5 O-cm). OLEDs fabricated with the ZAZ electrodes showed reduced leakage compared to control OLEDs on ITO and reduced ohmic losses at high current densities. At a luminance of 25000 cd/m2, the lum/W efficiency of the ZAZ electrode based device improved by 5% compared to the device on ITO. A normalized intensity graph of the colour output from the green OLEDs shows that ZAZ electrodes allow for a broader spectral output in the green wavelength region of peak photopic sensitivity compared to ITO. The results have implications for electrode choice in display technology.

Sivaramakrishnan, Karthik

377

Flexible and optically transparent silver nano-islands film  

NASA Astrophysics Data System (ADS)

We report a cost effective and facile way to synthesize flexible, transparent conductor using oblique angle deposition (OAD). A flexible Ag islands film with transmittance of 28.02 % at 550 nm is obtained with only one step on Polydimethylsiloxane (PDMS) substrate before stretching. The transperacy of the film increased upto 35.29 % at 550 nm under tensile strain of 40 %. As an application, these stretchable, transparent conductive films can be used as electrodes, capacitive pressure sensors for mechanically compliant optoelectronic devices.

Goel, Pratibha; Kumar, Samir; Singh, J. P.

2014-04-01

378

Transparencies and Reflections.  

ERIC Educational Resources Information Center

Discusses the use of perspective, or showing things as the human eye sees them, when creating reflections and transparencies in works of art. Provides examples of artwork using transparency, reflection, and refraction by M. C. Escher, Richard Estes, and Janet Fish to give students an opportunity to learn about these three art techniques. (CMK)

Hubbard, Guy

1999-01-01

379

Towards colorless transparent organic transistors: potential of benzothieno[3,2-b]benzothiophene-based wide-gap semiconductors.  

PubMed

Colorless, highly transparent organic thin-film transistors (TOTFTs) with high performance are realized based on benzothieno[3,2-b]benzothiophene (BTBT) derivatives that simultaneously exhibit a wide energy gap and high transport properties. Multilayer transparent source/drain electrodes maintain the transparency, and ultrathin fluoropolymer dielectric layers enable stable, low-voltage operation of the proposed TOTFTs. PMID:24496927

Moon, Hanul; Cho, Hyunsu; Kim, Mincheol; Takimiya, Kazuo; Yoo, Seunghyup

2014-05-21

380

Flexible and Transparent Memory: Non-Volatile Memory Based on Graphene Channel Transistor for Flexible and Transparent Electronics Applications  

Microsoft Academic Search

A Flexible and Transparent charge trap Memory (FTM) based on a single-layer graphene (SLG) channel with a ITO gate electrode was fabricated on a flexible and transparent poly-ethylene naphtalate (PEN) substrate. Triple high-k dielectric stacks Al2O3- AlOx-Al2O3 (AAA) were used as a data storage layer. The FTM shows memory characteristics with a memory window larger than 7V while maintaining ~80%

Sung Min Kim; Emil B. Song; Sejoon Lee; Jinfeng Zhou; Sunae Seo; David H. Seo; Kang L. Wang

2012-01-01

381

Application of microstrip proportional counters at the Danish Space Research Institute  

Microsoft Academic Search

The low energy proportional counter LEPC (0.2-8 keV) and the high energy proportional counter HEPC (2-25 keV) for the Danish-Russian X-ray telescopes XSPECT\\/SODART are presently being tested at DSRI. The sensor principle of these detectors is based on the novel microstrip proportional counter (MSPC) where the strip electrodes are deposited by photolithography onto a rigid substrate. The MSPC offers many

C. Budtz-Jørgensen; A. Bahnsen; M. Møhl Madsen; C. Olesen; P. Jonasson; H. W. Schnopper

1994-01-01

382

High-Energy\\/Low-Energy Proportional Counter (HEPC\\/LEPC) detector systems on the SRG  

Microsoft Academic Search

The low energy proportional counter LEPC (0.2 - 8 keV) and the high energy proportional counter HEPC (2 - 25 keV) for the Danish-Russian X-ray telescopes XSPECT\\/SODART are presently being tested at DSRI. The sensor principle of these detectors is based on the novel micro strip gas counter (MSGC) where the strip electrodes are deposited by photolithography onto a rigid

Carl C. Budtz-Joergensen; Axel Bahnsen; M. M. Madsen; C. Olesen; P. Jonasson; Herbert W. Schnopper

1994-01-01

383

Microstrip proportional counters for X-ray astronomy  

Microsoft Academic Search

Four position sensitive proportional counters will be delivered by the Danish Space Research Institute as focal plane instruments for the Soviet Danish Röntgen Telescope (SODART). These detectors will incorporate the novel microstrip electrode design. This design has been tested with xenon gas and an 55Fe X-ray source. The energy resolution is better than 14% FWHM up to gas gains of

Carl Budtz-Jørgensen; A. Bahnsen; C. Olesen; M. M. Madsen; P. Jonasson; H. W. Schnopper; A. Oed

1991-01-01

384

Compressor surge counter  

DOEpatents

A surge counter for a rotating compressor is provided which detects surging by monitoring the vibration signal from an accelerometer mounted on the shaft bearing of the compressor. The circuit detects a rapid increase in the amplitude envelope of the vibration signal, e.g., 4 dB or greater in less than one second, which is associated with a surge onset and increments a counter. The circuit is rendered non-responsive for a period of about 5 seconds following the detection which corresponds to the duration of the surge condition. This prevents multiple registration of counts during the surge period due to rapid swings in vibration amplitude during the period.

Castleberry, Kimberly N. (Harriman, TN)

1983-01-01

385

Monitoring of morphology and physical properties of cultured cells using a micro camera and a quartz crystal with transparent indium tin oxide electrodes after injections of glutaraldehyde and trypsin  

Microsoft Academic Search

For investigating the effects of chemical stimulation to cultured cells, we have developed a quartz crystal sensor system with a micro charge-coupled device (CCD) camera that enables microphotograph imaging simultaneously with quartz crystal measurement. Human hepatoma cell line (HepG2) cells were cultured on the quartz crystal through a collagen film. The electrode of the quartz crystal was made of indium

Hyen-Wook Kang; Kazumi Ida; Yuji Yamamoto; Hiroshi Muramatsu

2008-01-01

386

A Dictionary for Transparency  

SciTech Connect

There are many terms that are used in association with the U.S. Defense Threat Reduction Agency (DTRA) Transparency Project associated with the Mayak Fissile Materials Storage Facility. This is a collection of proposed definitions of these terms.

Kouzes, Richard T.

2001-11-15

387

Air-ion counter and mobility spectrometer  

NASA Astrophysics Data System (ADS)

Mono-electrode self "zeroing" air-ion counter and mobility (size) scanning spectrometer (CDI-011) based on the Gerdien aspirated condenser principle has been developed. Instrument is intended for short- and long-term indoor and outdoor air-ion concentration measurements and scanning of air-ions by mobility. Measuring small currents (typically 10-14 A) generated by the air-ions in outdoor conditions is demanding and causes many problems related to change of temperature, relative humidity, wind and electromagnetic noise. Also, measuring of both ion polarities with mono electrode detector require alternate changes of the polarizing voltage sign which produces capacitive current spikes. Various techniques, including "zeroing" method, have been applied to successfully overcome most of these measuring interferences.

Kolarž, Predrag; Miljkovi?, Budimir; ?urguz, Zoran

2012-05-01

388

California Science Explorer Transparencies  

NSDL National Science Digital Library

This collection of transparencies features materials for life science, earth science, and physical sciences. The transparencies are downloadable and printable, or can be viewed on-screen. Earth Science topics include plate tectonics and the Earth's structure; landforms and weathering; water, hydrology, and weather; and ecosystems and food webs. Life science topics include, among others, evolution and the Earth's history, and structure and function in living things. Physical science topics include motion, forces, and energy; sound and light; and electricity and magnetism.

389

FLEXIBLE GEIGER COUNTERS. Final Report  

Microsoft Academic Search

Long flexible Geiger counters were constructed from materials such as ; certain vacuum cleaner hoses. The anode is maintained in an axial position ; during coiling of the counter by ndeans of polystyrene or polyethylene spacer ; disks. The cathode is a wire spiraled on the outside of the counter. Pulse ; heights are smaller than those from a comparable

H. G. Richter; A. S. Jr. Gillespie

1961-01-01

390

Countering rumors about contraceptives.  

PubMed

Rumors are among the serious problems of the National Population Program today. The principles related to the origin of rumors, who starts rumors pertaining to family planning, and how they spread are outlined. The basic approach in countering rumors for the pill and IUD is diagrammed so that each potential rumor is countered by a medical or nonmedical/technical explanation. Strategies used by information-education-communication programs to prevent rumors such as the small group discussion, selection and training of motivators, and use of mass media are discussed. Rumors about family planning are counteracted not with the use of elaborate techniques but with clear and fairly simple reassurances supported by medical evidence and case histories. PMID:12308274

Del Rosario, M L

1976-01-01

391

Fully transparent thin-film transistors based on aligned single-walled carbon nanotube arrays  

Microsoft Academic Search

The work describes the first demonstration of fully transparent thin-film-transistors (TFTs) based on well-aligned single-walled carbon nanotube (SWNT) arrays with indium tin oxide (ITO) source\\/drain\\/gate electrodes. The fully transparent SWNT-TFTs could be attractive candidates for future flexible\\/ or transparent electronics. The transistors provide suitable current levels to drive OLED pixels (e.g. for high resolution displays), and operated at relatively low

Sunkook Kim; Sanghyun Ju; David B Janes; Saeed Mohammadi

2008-01-01

392

Simple Coulter Counter  

NSDL National Science Digital Library

Students build and use a very basic Coulter electric sensing zone particle counter to count an unknown number of particles in a sample of "paint" to determine if enough particles per ml of "paint" exist to meet a quality standard. In a lab experiment, student teams each build an apparatus and circuit, set up data acquisition equipment, make a salt-soap solution, test liquid flow in the apparatus, take data, and make graphs to count particles.

Nsf Career Award And Ret Program

393

Semi-transparent inverted organic solar cells  

NASA Astrophysics Data System (ADS)

We will present efficient semi-transparent bulk-heterojunction [regioregular of poly(3-hexylthiophene): (6,6)-phenyl C61 butyric acid methyl ester] solar cells with an inverted device architecture. Highly transparent ZnO and TiO2 films prepared by Atomic Layer Deposition are used as cathode interlayers on top of ITO. The topanode consists of a RF-sputtered ITO layer. To avoid damage due to the plasma deposition of this layer, a sputtering buffer layer of MoO3 is used as protection. This concept allows for devices with a transmissivity higher than 60 % for wavelengths 650 nm. The thickness of the MoO3 buffer has been varied in order to study its effect on the electrical properties of the solar cell and its ability to prevent possible damage to the organic active layers upon ITO deposition. Without this buffer or for thin buffers it has been found that device performance is very poor concerning the leakage current, the fill factor, the short circuit current and the power conversion efficiencies. As a reference inverted solar cells with a metal electrode (Al) instead of the ITO-top contact are used. The variation between the PCE of top versus conventional illumination of the semi-transparent cells was also examined and will be interpreted in view of the results of the optical simulation of the dielectric device stack with and without reflection top electrode. Power conversion efficiencies of 2-3 % for the opaque inverted solar cells and 1.5-2.5 % for the semi-transparent devices were obtained under an AM1.5G illumination.

Schmidt, H.; Winkler, T.; Tilgner, M.; Flügge, H.; Schmale, S.; Bülow, T.; Meyer, J.; Johannes, H.-H.; Riedl, T.; Kowalsky, W.

2009-08-01

394

Zinc oxyfluoride transparent conductor  

DOEpatents

Transparent, electrically conductive and infrared-reflective films of zinc oxyfluoride are produced by chemical vapor deposition from vapor mixtures of zinc, oxygen and fluorine-containing compounds. The substitution of fluorine for some of the oxygen in zinc oxide results in dramatic increases in the electrical conductivity. For example, diethyl zinc, ethyl alcohol and hexafluoropropene vapors are reacted over a glass surface at 400.degree. C. to form a visibly transparent, electrically conductive, infrared reflective and ultraviolet absorptive film of zinc oxyfluoride. Such films are useful in liquid crystal display devices, solar cells, electrochromic absorbers and reflectors, energy-conserving heat mirrors, and antistatic coatings.

Gordon, Roy G. (Cambridge, MA)

1991-02-05

395

Electrode compositions  

DOEpatents

An electrode composition for use as an electrode in a non-aqueous battery system. The electrode composition contains an electrically active powder in a solid polymer and, as a dispersant, a C.sub.8 -C.sub.15 alkyl capped oligomer of a hexanoic acid that is electrochemically inert at 2.5-4.5 volts.

Block, Jacob (Rockville, MD); Fan, Xiyun (Orange, TX)

1998-01-01

396

Electrode compositions  

DOEpatents

An electrode composition is described for use as an electrode in a non-aqueous battery system. The electrode composition contains an electrically active powder in a solid polymer and, as a dispersant, a C{sub 8}-C{sub 15} alkyl capped oligomer of a hexanoic acid that is electrochemically inert at 2.5--4.5 volts.

Block, J.; Fan, X.

1998-10-27

397

Boron-lined proportional counters with improved neutron sensitivity  

NASA Astrophysics Data System (ADS)

Boron-lined proportional counters with higher neutron sensitivity have been developed by introducing baffle structures within the sensitive volume. the results are compared to devices developed with multiple cathode assemblies in a single enclosure. in either case, the increase in the boron-coated surface area results in higher neutron sensitivity. one of these counters has 51 annular baffles coated with natural boron with 10 mm hole for the anode wire to pass through. filled with p-10 gas at 20 cm hg, it has an overall diameter of 30 and 300 mm length. multiple dip coating method was employed for better uniformity in boron thickness. the neutron sensitivity of this counter is 1.6 cps/nv, which is 2.5 times that of a counter with standard electrode geometry. another counter was developed with three cathode assemblies (30 mm ID×300 mm) coated with 92% 10B while the third has seven assemblies coated with natural boron (16 mm ID×750 mm length). the neutron sensitivity is 10 and 5.5 cps/nv, respectively. the change in neutron sensitivity in 8 R/h gamma background was 12%, 18% and 22% in the case of the counter with baffles, 3 and 7 cathode assemblies.

Dighe, P. M.; Prasad, D. N.; Prasad, K. R.; Kataria, S. K.; Athavale, S. N.; Pappachan, A. L.; Grover, A. K.

2003-01-01

398

Organic solar cells with carbon nanotube network electrodes  

Microsoft Academic Search

We fabricated flexible transparent conducting electrodes by printing films of single-walled carbon nanotube (SWNT) networks on plastic and have demonstrated their use as transparent electrodes for efficient, flexible polymer-fullerene bulk-heterojunction solar cells. The printing method produces relatively smooth, homogeneous films with a transmittance of 85% at 550 nm and a sheet resistance (Rs) of 200 Omega\\/□. Cells were fabricated on

Michael W. Rowell; Mark A. Topinka; Michael D. McGehee; Hans-Jürgen Prall; Gilles Dennler; Niyazi Serdar Sariciftci; Liangbing Hu; George Gruner

2006-01-01

399

Transparent spinel development  

NASA Astrophysics Data System (ADS)

The optical and mechanical properties of polycrystalline MgAl2O4 spinel make this material of interest for transparent armor and for window and dome applications in the 0.3 micrometers to 5.5 micrometers range. Spinel was briefly produced commercially, and qualified for a range of dome and window applications in the early 1990's. Since 1993 however, there has been no commercial producer and consequently the interest in the application of spinel has waned. This paper summarizes development efforts by Technology Assessment and Transfer (TA&T) to fabricate transparent spinel with high optical quality for both transparent armor, and a selection of window and dome applications. A cooperative research and development agreement between TA&T and the US Army Research Laboratory is focused at optimizing processing parameters to maximize strength and transparency while minimizing the costs for fabrication by the hot-press/HIP approach. Present interest is in fabricating large armor panels of spinel up to 15 inches square and 0.5 inches thick, and in the fabrication of thinner windows and domes with the view to establishing TA&T as a commercial supplier of spinel in the near future.

Patterson, Mark; Caiazza, Jenni E.; Roy, Donald W.

2000-10-01

400

The Limits of Transparency  

Microsoft Academic Search

This paper probes the limits of transparency in monetary policymaking along two dimensions: feasibility and desirability. It argues that, due to limited knowledge about the economy, even central banks (CBs) that are considered champions of openness are not very clear about their measurement of the output gap and about their beliefs regarding the effect of policy on inflationary expectations. Consequently,

Alex Cukierman

2007-01-01

401

Capitalism and transparency  

Microsoft Academic Search

Purpose – The purpose of this paper is to critically examine the international NGO Transparency International's (TI) role in combating corruption, focusing particularly on TI's response to the global financial crisis of 2008. Design\\/methodology\\/approach – The paper is based on a review of scholarly articles, newspaper reports, and TI publications. Findings – The paper concludes that TI's uncritical approach to

Jonathan Murphy

2011-01-01

402

Working Electrodes  

NASA Astrophysics Data System (ADS)

In electrochemistry an electrode is an electronic conductor in contact with an ionic conductor. The electronic conductor can be a metal, or a semiconductor, or a mixed electronic and ionic conductor. The ionic conductor is usually an electrolyte solution; however, solid electrolytes and ionic melts can be used as well. The term "electrode" is also used in a technical sense, meaning the electronic conductor only. If not specified otherwise, this meaning of the term "electrode" is the subject of the present chapter. In the simplest case the electrode is a metallic conductor immersed in an electrolyte solution. At the surface of the electrode, dissolved electroactive ions change their charges by exchanging one or more electrons with the conductor. In this electrochemical reaction both the reduced and oxidized ions remain in solution, while the conductor is chemically inert and serves only as a source and sink of electrons. The technical term "electrode" usually also includes all mechanical parts supporting the conductor (e.g., a rotating disk electrode or a static mercury drop electrode). Furthermore, it includes all chemical and physical modifications of the conductor, or its surface (e.g., a mercury film electrode, an enzyme electrode, and a carbon paste electrode). However, this term does not cover the electrolyte solution and the ionic part of a double layer at the electrode/solution interface. Ion-selective electrodes, which are used in potentiometry, will not be considered in this chapter. Theoretical and practical aspects of electrodes are covered in various books and reviews [1-9].

Komorsky-Lovri?, Šebojka

403

Low latency counter event indication  

DOEpatents

A hybrid counter array device for counting events with interrupt indication includes a first counter portion comprising N counter devices, each for counting signals representing event occurrences and providing a first count value representing lower order bits. An overflow bit device associated with each respective counter device is additionally set in response to an overflow condition. The hybrid counter array includes a second counter portion comprising a memory array device having N addressable memory locations in correspondence with the N counter devices, each addressable memory location for storing a second count value representing higher order bits. An operatively coupled control device monitors each associated overflow bit device and initiates incrementing a second count value stored at a corresponding memory location in response to a respective overflow bit being set. The incremented second count value is compared to an interrupt threshold value stored in a threshold register, and, when the second counter value is equal to the interrupt threshold value, a corresponding "interrupt arm" bit is set to enable a fast interrupt indication. On a subsequent roll-over of the lower bits of that counter, the interrupt will be fired.

Gara, Alan G. (Mount Kisco, NY); Salapura, Valentina (Chappaqua, NY)

2010-08-24

404

Low latency counter event indication  

DOEpatents

A hybrid counter array device for counting events with interrupt indication includes a first counter portion comprising N counter devices, each for counting signals representing event occurrences and providing a first count value representing lower order bits. An overflow bit device associated with each respective counter device is additionally set in response to an overflow condition. The hybrid counter array includes a second counter portion comprising a memory array device having N addressable memory locations in correspondence with the N counter devices, each addressable memory location for storing a second count value representing higher order bits. An operatively coupled control device monitors each associated overflow bit device and initiates incrementing a second count value stored at a corresponding memory location in response to a respective overflow bit being set. The incremented second count value is compared to an interrupt threshold value stored in a threshold register, and, when the second counter value is equal to the interrupt threshold value, a corresponding "interrupt arm" bit is set to enable a fast interrupt indication. On a subsequent roll-over of the lower bits of that counter, the interrupt will be fired.

Gara, Alan G. (Mount Kisco, NY) [Mount Kisco, NY; Salapura, Valentina (Chappaqua, NY) [Chappaqua, NY

2008-09-16

405

Magnetron cathodes in plasma electrode Pockels cells  

DOEpatents

Magnetron cathodes, which produce high current discharges, form greatly improved plasma electrodes on each side of an electro-optic crystal. The plasma electrode has a low pressure gas region on both sides of the crystal. When the gas is ionized, e.g., by a glow discharge in the low pressure gas, the plasma formed is a good conductor. The gas electrode acts as a highly uniform conducting electrode. Since the plasma is transparent to a high energy laser beam passing through the crystal, the plasma is transparent. A crystal exposed from two sides to such a plasma can be charged up uniformly to any desired voltage. A typical configuration utilizes helium at 50 millitorr operating pressure and 2 kA discharge current. The magnetron cathode produces a more uniform plasma and allows a reduced operating pressure which leads to lower plasma resistivity and a more uniform charge on the crystal. 5 figs.

Rhodes, M.A.

1995-04-25

406

Transparent conductive thin film of ultra large reduced graphene oxide monolayers  

NASA Astrophysics Data System (ADS)

There is a great interest in the use of graphene sheets in transparent electrodes with low cost and high transparency and conductivity. Here, the production of transparent conductive thin film of ultra large reduced graphene oxide monolayers was investigated. Graphene oxide monolayers were produced using a modified Hummers method. Then, the ultralarge monolayers of graphene oxide to about 70 ?m as liquid crystalline dispersion were used for production of thin films; which were reduced by hydriodic acid. The produced low cost thin films had high transparency up to 70%, electrical resistance as low as 200 ?/sq and high mechanical properties as 4.6 GPa in Young's modulus. The improved properties suggest that the produced thin films could successfully be used as transparent electrodes for different applications.

Nekahi, A.; Marashi, P. H.; Haghshenas, D.

2014-03-01

407

On-Chip Integration of Microfluid and Cell Detector for Micro Cell Counter  

Microsoft Academic Search

This paper describes on-chip integration of microfluid and cell detector for a micro cell counter. The device consists of a microchannel, a microwindow, a boron diffused resistor (BDR). It utilizes photoconductive property of the BDR, for detection, which shows the resistance change up to 10 % when illuminated. The microchannel is made by transparent PDMS and the microwindow is made

Sang Uk Son; Yo Han Choi; Seung Seok Lee

2004-01-01

408

Note: Microelectromechanical systems Coulter counter for cell monitoring and counting  

NASA Astrophysics Data System (ADS)

This note describes the design, fabrication, and testing of a novel microelectromechanical systems Coulter counter. The Coulter counter will be used to detect and monitor impedance changes of cells as a function of time in response to different experimental extracellular environments. The device consists of SU-8 (negative photoresist) microchannels, vertical electroplated electrodes, polydimethylsiloxane cover, and is divided into a passive mixing region, a focusing region using negative dielectrophoretic forces, and a measuring region defined by multiple electroplated electrode pairs. The devices were tested using both microbeads in saline water and fibroblast cells in phosphate buffered saline solution. The results show that the proposed microsystem is capable of monitoring impedance of cells at different positions along the Coulter microchannel.

Wu, Yifan; Benson, James D.; Critser, John K.; Almasri, Mahmoud

2010-07-01

409

VLSI binary updown counter  

NASA Technical Reports Server (NTRS)

A pipeline binary updown counter is comprised of simple stages that may be readily replicated. Each stage is defined by the Boolean logic equation: A(sub n)(t) = A(sub n)(t - 1) exclusive OR (U AND P(sub n)) inclusive OR (D AND Q(sub n)), where A(sub n)(t) denotes the value of the nth bit at time t. The input to the counter has three values represented by two binary signals U and D such that if both are zero, the input is zero, if U = 0 and D = 1, the input is -1 and if U = 1 and D = 0, the input is +1. P(sub n) represents a product of A(sub k)'s for 1 is less than or equal to k is less than or equal to -1, while Q(sub n) represents the product of bar A's for 1 is less than or equal to K is less than or equal to n - 1, where bar A(sub k) is the complement of A(sub k) and P(sub n) and Q(sub n) are expressed as the following two equations: P(sub n) = A(sub n - 1) A(sub n - 2)...A(sub 1) and Q(sub n) = bar A(sub n - 1) bar A(sub n - 2)...bar A(sub 1), which can be written in recursive form as P(sub n) = P(sub n - 1) AND bar A(sub n - 1) and Q(sub n) = Q(sub n - 1) AND bar A(sub n - 1) with the initial values P(sub 1) = 1 and Q(sub 1) = 1.

Truong, Trieu-Kie (inventor); Hsu, In-Shek (inventor); Reed, Irving S. (inventor)

1989-01-01

410

Space and power efficient hybrid counters array  

DOEpatents

A hybrid counter array device for counting events. The hybrid counter array includes a first counter portion comprising N counter devices, each counter device for receiving signals representing occurrences of events from an event source and providing a first count value corresponding to a lower order bits of the hybrid counter array. The hybrid counter array includes a second counter portion comprising a memory array device having N addressable memory locations in correspondence with the N counter devices, each addressable memory location for storing a second count value representing higher order bits of the hybrid counter array. A control device monitors each of the N counter devices of the first counter portion and initiates updating a value of a corresponding second count value stored at the corresponding addressable memory location in the second counter portion. Thus, a combination of the first and second count values provide an instantaneous measure of number of events received.

Gara, Alan G. (Mount Kisco, NY); Salapura, Valentina (Chappaqua, NY)

2010-03-30

411

Space and power efficient hybrid counters array  

DOEpatents

A hybrid counter array device for counting events. The hybrid counter array includes a first counter portion comprising N counter devices, each counter device for receiving signals representing occurrences of events from an event source and providing a first count value corresponding to a lower order bits of the hybrid counter array. The hybrid counter array includes a second counter portion comprising a memory array device having N addressable memory locations in correspondence with the N counter devices, each addressable memory location for storing a second count value representing higher order bits of the hybrid counter array. A control device monitors each of the N counter devices of the first counter portion and initiates updating a value of a corresponding second count value stored at the corresponding addressable memory location in the second counter portion. Thus, a combination of the first and second count values provide an instantaneous measure of number of events received.

Gara, Alan G. (Mount Kisco, NY) [Mount Kisco, NY; Salapura, Valentina (Chappaqua, NY) [Chappaqua, NY

2009-05-12

412

Liquid electrode  

DOEpatents

A dropping electrolyte electrode for use in electrochemical analysis of non-polar sample solutions, such as benzene or cyclohexane. The liquid electrode, preferably an aqueous salt solution immiscible in the sample solution, is introduced into the solution in dropwise fashion from a capillary. The electrolyte is introduced at a known rate, thus, the droplets each have the same volume and surface area. The electrode is used in making standard electrochemical measurements in order to determine properties of non-polar sample solutions.

Ekechukwu, Amy A. (Augusta, GA)

1994-01-01

413

Electrode catalyst  

SciTech Connect

An electrode catalyst for a fuel cell comprising at least one boride of molybdenum is disclosed. The electrode catalyst is far more excellent than conventional catalysts such as platinum black in that the resistance to acids is very high, that the polarization is little, that the price is low, etc. It is particularly suitable as an electrode catalyst for a fuel cell employing an acidic electrolyte.

Kudo, T.; Obayashi, H.

1980-12-30

414

Transparent gate silicon photodetectors  

Microsoft Academic Search

Optical and electrical properties of silicon imaging devices with In2O3-SnO2gates are reported. The optically transparent electrically conducting films were sputtered from both glass and metal targets. Quantum efficiencies of such devices are significantly better than photodiodes or polysilicon gate devices. The electrical properties such as dark current and interface state density are as low as conventional aluminum gate devices after

DIETER K. SCHRODER

1978-01-01

415

Transparent Gate Silicon Photodetectors  

Microsoft Academic Search

Optical and electrical properties of silicon imaging devices with In2O3-SnO2 gates are reported. The optically transparent electrically conducting films were sputtered from both glass and metal targets. Quantum efficiencies of such devices are significantly better than photodiodes or polysilicon gate devices. The electrical properties such as dark current and interface state density are as low as conventional aluminum gate devices

DIETER K. SCHRODER

1978-01-01

416

Transparent spinel development  

Microsoft Academic Search

The optical and mechanical properties of polycrystalline MgAl2O4 spinel make this material of interest for transparent armor and for window and dome applications in the 0.3 micrometers to 5.5 micrometers range. Spinel was briefly produced commercially, and qualified for a range of dome and window applications in the early 1990's. Since 1993 however, there has been no commercial producer and

Mark Patterson; Jenni E. Caiazza; Donald W. Roy

2000-01-01

417

Transparency microplates under impact.  

PubMed

Transparency microplates enable biochemical analysis in resource-limited laboratories. During the process of transfer, the analytes tittered into the wells may undergo spillage from one well to another due to lateral impact. Sidelong impact tests conducted found the absence of non-linear effects (e.g., viscoelastic behavior) but high energy loss. Finite element simulations conducted showed that the rectangular plate holding the transparencies could undergo z-axis deflections when a normal component of the force was present despite constraints being used. High speed camera sequences confirmed this and also showed the asymmetrical z-axis deflection to cause the contact line closer to impact to displace first when the advancing condition was exceeded. Capillary waves were found to travel toward the contact line at the opposite end, where if the advancing contact angle condition was exceeded, also resulted in spreading. The presence of surface scribing was found to limit contact line movement better. With water drops dispensed on scribed transparencies, immunity from momentum change of up to 9.07kgm/s on impact was possible for volumes of 40?L. In the case of glycerol drops immunity from momentum change of up to 9.07kgm/s on impact extended to volumes of 90?L. The improved immunity of glycerol was attributed to its heightened dampening characteristics and its higher attenuation of capillary waves. Overall, scribed transparency microplates were able to better withstand spillage from accidental impact. Accidental impact was also found not to cause any detrimental effects on the fluorescence properties of enhanced green fluorescent protein samples tested. PMID:24863765

Lau, Chun Yat; Roslan, Zulhanif; Cheong, Brandon Huey-Ping; Chua, Wei Seong; Liew, Oi Wah; Ng, Tuck Wah

2014-07-15

418

Over-the-Counter Medicines  

MedlinePLUS

Over-the-counter (OTC) medicines are drugs you can buy without a prescription. Some OTC medicines relieve aches, pains and itches. Some prevent or cure ... the Food and Drug Administration decides whether a medicine is safe enough to sell over-the-counter. ...

419

High Resolution Time Interval Counter.  

National Technical Information Service (NTIS)

In recent years, we have developed two types of high resolution, multi-channel time interval counters. In the NIST two-way time transfer MODEM application, the counter is designed for operating primarily in the interrupt- driven mode, with 3 start channel...

D. D. Davis M. A. Lombardi V. S. Zhang

1994-01-01

420

Graphene-carbon nanotube hybrid transparent conductive films  

NASA Astrophysics Data System (ADS)

Graphene films grown by chemical vapor deposition of hydrocarbon gases on metal surfaces have been integrated with single-walled carbon nanotube (SWNT) films. Using simple thin film fabrication methods and the sequential deposition of these two components we obtained graphene/SWNT hybrid films with good structural quality. Obtained graphene/SWNT films possess opto-electrical properties better than that of pure graphene or SWNT films, making them promising for transparent conductive film (TCF) applications. The hybrid films have been tested as a transparent electrode in electrochromic (EC) devices to replace indium tin oxide (ITO) TCFs.

Kholmanov, Iskandar N.; Kim, TaeYoung; Domingues, Sergio H.; Kim, Jin-Young; Tan, Cheng; Magnuson, Carl W.; Li, Huifeng; Piner, Richard; Ruoff, Rodney S.

2013-06-01

421

Counters and Scalers Based Upon Continued Fractions.  

National Technical Information Service (NTIS)

A design for binary counters with counting and inhibition inputs is described. The counters are interconnected in such a way that counter i drives counter i+1 and inhibits counter i-1. It is shown that such an arrangement corresponds to a continued fracti...

E. J. Vanlantschoot J. Vandewalle

1972-01-01

422

Reference Electrodes  

NASA Astrophysics Data System (ADS)

In most electrochemical measurements, it is necessary to keep one of the electrodes in an electrochemical cell at a constant potential. This so-called reference electrode allows control of the potential of a working electrode (e.g. in voltammetry) or the measurement of an indicator electrode (e.g. in potentiometry, see Chap. II.9). The standard hydrogen electrode plays the role of a basic reference element in electrochemical devices; however, in practice, it is difficult to handle. Therefore, secondary reference electrodes are preferred in most experiments. A secondary reference electrode must fulfil the following criteria: (i) it should be chemically and electrochemically reversible, i.e. its potential is governed by the Nernst equation and does not change in time; (ii) the potential must remain almost constant when a small current passes through the electrode and reverse to its original value after such small current flow (i.e. a non-polarisable electrode); and (iii) the thermal coefficient of potential should be small.

Kahlert, Heike

423

Doped graphene electrodes for organic solar cells  

NASA Astrophysics Data System (ADS)

In this work graphene sheets grown by chemical vapor deposition (CVD) with controlled numbers of layers were used as transparent electrodes in organic photovoltaic (OPV) devices. It was found that for devices with pristine graphene electrodes, the power conversion efficiency (PCE) is comparable to their counterparts with indium tin oxide (ITO) electrodes. Nevertheless, the chances for failure in OPVs with pristine graphene electrodes are higher than for those with ITO electrodes, due to the surface wetting challenge between the hole-transporting layer and the graphene electrodes. Various alternative routes were investigated and it was found that AuCl3 doping on graphene can alter the graphene surface wetting properties such that a uniform coating of the hole-transporting layer can be achieved and device success rate can be increased. Furthermore, the doping both improves the conductivity and shifts the work function of the graphene electrode, resulting in improved overall PCE performance of the OPV devices. This work brings us one step further toward the future use of graphene transparent electrodes as a replacement for ITO.

Park, Hyesung; Rowehl, Jill A.; Kim, Ki Kang; Bulovic, Vladimir; Kong, Jing

2010-12-01

424

Method for control of edge effects of oxidant electrode  

DOEpatents

Described is an electrode assembly comprising; a. a porous electrode having a first and second exterior face with a cavity formed in the interior between said exterior faces thereby having first and second interior faces positioned opposite the first and second exterior faces; b. a counter electrode positioned facing each of the first and second exterior faces of the porous electrode; c. means for passing an oxidant through said porous electrode; and d. screening means for blocking the interior face of the porous electrode a greater amount than the blocking of the respective exterior face of the porous electrode, thereby maintaining a differential of oxidant electrode surface between the interior face and the exterior face. The electrode assembly is useful in a metal, halogen, halogen hydrate electrical energy storage device.

Carr, Peter (Utica, MI); Chi, Chen H. (Sterling Heights, MI)

1980-12-23

425

Liquid Crystal Addressing by Graphene Electrodes Made from Graphene Oxide  

Microsoft Academic Search

The electrooptic characteristics of the field-induced reorientation of a nematic liquid crystal are studied using graphene layers as transparent conductive electrodes. The covering of a large area with highly conductive graphene was achieved by the thermal reduction of a graphene oxide film. The conductivity of the graphene electrode provides electrooptic properties that are comparable to those of liquid crystal cells

Gaby Nordendorf; Olga Kasdorf; Heinz-S. Kitzerow; Yanyu Liang; Xinliang Feng; Klaus Müllen

2010-01-01

426

Carbon Nanotubes as Counter Electrodes for Gratzel Solar Cells  

Microsoft Academic Search

The role of interfaces is very critical for solar cell devices which use nanostructured materials. Dye Sensitized Solar Cells (DSSC) are devices which parts are interfacial in character and physico --chemical processes occur at the interface of two distinct media. DSSC are of great interest due to combination of their high efficiency and relatively low cost. An effective counterelectrode with

Hasan Shodive; Ali Aliev; Mei Zhang; Sergey Lee; Ray Baughman; Anvar Zakhidov

2006-01-01

427

Highly efficient fully transparent inverted OLEDs  

NASA Astrophysics Data System (ADS)

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

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

2007-10-01

428

Metal Rubber electrodes for active polymer devices  

Microsoft Academic Search

This paper describes the use of Metal Rubber, which is an electrically conductive, low modulus, and optically transparent free-standing nanocomposite, as an electrode for active polymer devices. With its controllable and tailorable properties [such as modulus (from ~ 1 MPa to 100 MPa), electrical conductivity, sensitivity to flex and strain, thickness, transmission, glass transition, and more], Metal Rubber exhibits massive

Andrea B. Hill; Richard O. Claus; Jennifer H. Lalli; Jeffrey B. Mecham; Bradley A. Davis; Richard M. Goff; Sumitra Subrahmanayan

2005-01-01

429

A portable neutron coincidence counter  

SciTech Connect

Pacific Northwest National Laboratory has designed and constructed a prototype portable neutron coincidence counter intended for use in a variety of applications, such as the verification and inspection of weapons components, safety measurements for novel and challenging situations, portable portal deployment to prevent the transportation of fissile materials, uranium enrichment measurements in hard-to-reach locations, waste assays for objects that cannot be measured by existing measurement systems, and decontamination and decommissioning. The counting system weighs less than 40 kg and is composed of parts each weighing no more than 5 kg. In addition, the counter`s design is sufficiently flexible to allow rapid, reliable assembly around containers of nearly arbitrary size and shape. The counter is able to discern the presence of 1 kg of weapons-grade plutonium within an ALR-8 (30-gal drum) in roughly 100 seconds and 10 g in roughly 1000 seconds. The counter`s electronics are also designed for maximum adaptability, allowing operation under a wide variety of circumstances, including exposure to gamma-ray fields of 1 R/h. This report provides a detailed review of the design and construction process. Finally, preliminary experimental measurements that confirm the performance capabilities of this counter are discussed. 6 refs., 18 figs., 3 tabs.

Peurrung, A.J.; Bowyer, S.M.; Craig, R.A.; Dudder, G.B.; Knopf, M.A.; Panisko, M.E.; Reeder, P.L.; Stromswold, D.C.; Sunberg, D.S.

1996-11-01

430

Prospects of graphene electrodes in photovoltaics  

NASA Astrophysics Data System (ADS)

Transparent conductors (TCs) are becoming extremely popular in many different electronic applications such as touch panels, displays, light emitting devices, light sensors and solar cells. The commonly used electrode in these applications is Indium Tin Oxide (ITO). However, the cost of ITO is increasing rapidly due to the limited supply of Indium. Other issues such as lack of flexibility and cost of the deposition process make ITO less favorable in transparent electrode applications. Graphene has been under exploration as an alternative material for TC applications in the recent years. Graphene based TCs have been shown experimentally to exhibit promising electrical and optical properties. In this paper, the prospects of graphene for transparent conductors in photovoltaics are discussed. The recent advancements in this field as well as the theoretical predictions and possible pathways for improvements are presented. In the process section, we discuss methods to synthesize few-layer graphene (FLG) with high quality in a controllable manner.

Khatami, Yasin; Liu, Wei; Kang, Jiahao; Banerjee, Kaustav

2013-09-01

431

High resolution time interval counter  

NASA Technical Reports Server (NTRS)

In recent years, we have developed two types of high resolution, multi-channel time interval counters. In the NIST two-way time transfer MODEM application, the counter is designed for operating primarily in the interrupt-driven mode, with 3 start channels and 3 stop channels. The intended start and stop signals are 1 PPS, although other frequencies can also be applied to start and stop the count. The time interval counters used in the NIST Frequency Measurement and Analysis System are implemented with 7 start channels and 7 stop channels. Four of the 7 start channels are devoted to the frequencies of 1 MHz, 5 MHz or 10 MHz, while triggering signals to all other start and stop channels can range from 1 PPS to 100 kHz. Time interval interpolation plays a key role in achieving the high resolution time interval measurements for both counters. With a 10 MHz time base, both counters demonstrate a single-shot resolution of better than 40 ps, and a stability of better than 5 x 10(exp -12) (sigma(sub chi)(tau)) after self test of 1000 seconds). The maximum rate of time interval measurements (with no dead time) is 1.0 kHz for the counter used in the MODEM application and is 2.0 kHz for the counter used in the Frequency Measurement and Analysis System. The counters are implemented as plug-in units for an AT-compatible personal computer. This configuration provides an efficient way of using a computer not only to control and operate the counters, but also to store and process measured data.

Zhang, Victor S.; Davis, Dick D.; Lombardi, Michael A.

1995-01-01

432

Transparent, Translucent and Opaque  

NSDL National Science Digital Library

In this activity, students examine everyday objects with a flashlight and determine if they are transparent, translucent, or opaque. Common household materials such as wax paper, plastic wrap, aluminum foil, tissue, and food coloring are required. This activity can be used with pre-readers. The resource is part of the teacher's guide accompanying the video, NASA Why Files: The Case of the Mysterious Red Light. Lesson objectives supported by the video, additional resources, teaching tips and an answer sheet are included in the teacher's guide.

433

Multiple channel programmable coincidence counter  

SciTech Connect

A programmable digital coincidence counter having multiple channels and featuring minimal dead time. Neutron detectors supply electrical pulses to a synchronizing circuit which in turn inputs derandomized pulses to an adding circuit. A random access memory circuit connected as a programmable length shift register receives and shifts the sum of the pulses, and outputs to a serializer. A counter is input by the adding circuit and downcounted by the seralizer, one pulse at a time. The decoded contents of the counter after each decrement is output to scalers.

Arnone, Gaetano J. (Los Alamos, NM)

1990-01-01

434

Multiple channel programmable coincidence counter  

SciTech Connect

A programmable digital coincidence counter having multiple channels and featuring minimal dead time. Neutron detectors supply electrical pulses to a synchronizing circuit which in turn inputs derandomized pulses to an adding circuit. A random access memory circuit connected as a programmable length shift register receives and shifts the sum of the pulses, and outputs to a serializer. A counter is input by the adding circuit and downcounted by the serializer, one pulse at a time. The decoded contents of the counter after each decrement is output to scalers.

Arnone, G.J.

1989-02-27

435

Multiple channel programmable coincidence counter  

SciTech Connect

This patent describes a programmable digital coincidence counter having multiple channels and featuring minimal dead time. Neutron detectors supply electrical pulses to a synchronizing circuit which in turn inputs derandomized pulses to an adding circuit. A random access memory circuit connected as a programmable length shift register receives and shifts the sum of the pulses, and outputs to a serializer. A counter is input by the adding circuit and downcounted by the seralizer, one pulse at a time. The decoded contents of the counter after each decrement is output to scalers.

Arnone, G.J.

1990-04-24

436

Wetting transparency of graphene.  

PubMed

We report that graphene coatings do not significantly disrupt the intrinsic wetting behaviour of surfaces for which surface-water interactions are dominated by van der Waals forces. Our contact angle measurements indicate that a graphene monolayer is wetting-transparent to copper, gold or silicon, but not glass, for which the wettability is dominated by short-range chemical bonding. With increasing number of graphene layers, the contact angle of water on copper gradually transitions towards the bulk graphite value, which is reached for ~6 graphene layers. Molecular dynamics simulations and theoretical predictions confirm our measurements and indicate that graphene's wetting transparency is related to its extreme thinness. We also show a 30-40% increase in condensation heat transfer on copper, as a result of the ability of the graphene coating to suppress copper oxidation without disrupting the intrinsic wettability of the surface. Such an ability to independently tune the properties of surfaces without disrupting their wetting response could have important implications in the design of conducting, conformal and impermeable surface coatings. PMID:22266468

Rafiee, Javad; Mi, Xi; Gullapalli, Hemtej; Thomas, Abhay V; Yavari, Fazel; Shi, Yunfeng; Ajayan, Pulickel M; Koratkar, Nikhil A

2012-03-01

437

Wetting transparency of graphene  

NASA Astrophysics Data System (ADS)

We report that graphene coatings do not significantly disrupt the intrinsic wetting behaviour of surfaces for which surface-water interactions are dominated by van der Waals forces. Our contact angle measurements indicate that a graphene monolayer is wetting-transparent to copper, gold or silicon, but not glass, for which the wettability is dominated by short-range chemical bonding. With increasing number of graphene layers, the contact angle of water on copper gradually transitions towards the bulk graphite value, which is reached for ~6 graphene layers. Molecular dynamics simulations and theoretical predictions confirm our measurements and indicate that graphene’s wetting transparency is related to its extreme thinness. We also show a 30-40% increase in condensation heat transfer on copper, as a result of the ability of the graphene coating to suppress copper oxidation without disrupting the intrinsic wettability of the surface. Such an ability to independently tune the properties of surfaces without disrupting their wetting response could have important implications in the design of conducting, conformal and impermeable surface coatings.

Rafiee, Javad; Mi, Xi; Gullapalli, Hemtej; Thomas, Abhay V.; Yavari, Fazel; Shi, Yunfeng; Ajayan, Pulickel M.; Koratkar, Nikhil A.

2012-03-01

438

Liquid electrode  

DOEpatents

A dropping electrolyte electrode is described for use in electrochemical analysis of non-polar sample solutions, such as benzene or cyclohexane. The liquid electrode, preferably an aqueous salt solution immiscible in the sample solution, is introduced into the solution in dropwise fashion from a capillary. The electrolyte is introduced at a known rate, thus, the droplets each have the same volume and surface area. The electrode is used in making standard electrochemical measurements in order to determine properties of non-polar sample solutions. 2 figures.

Ekechukwu, A.A.

1994-07-05

439

Healthcare transparency: opportunity or mirage  

Microsoft Academic Search

Purpose – Healthcare is an ever-growing segment of the American economy. Transparency facilitates better decision-making and better outcomes measures. The purpose of this paper is to present the human and economic results of increasing transparency. Design\\/methodology\\/approach – The ASIMP Working Group on Healthcare Transparency represents a diverse yet conscilient group of practitioners, researchers, regulators, economists, and academics. Given the need

Russell Jaffe; Robert A. Nash; Richard Ash; Norman Schwartz; Robert Corish; Tammy Born; Harold Lazarus

2006-01-01

440

Junctionless in-plane-gate transparent thin-film transistors  

Microsoft Academic Search

Junctionless transparent electric-double-layer thin-film transistors with an in-plane-gate figure are fabricated on glass substrates at room temperature. The unique feature of such junctionless transistors is that the channel and source\\/drain electrodes are the same thin indium-tin-oxide film without any source\\/drain junction. Effective field-effect modulation of drain current can be obtained when the indium-tin-oxide thickness is reduced to 20 nm. Such

Jie Jiang; Jia Sun; Wei Dou; Bin Zhou; Qing Wan

2011-01-01

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