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1

Transparent nickel selenide alloy counter electrodes for bifacial dye-sensitized solar cells exceeding 10% efficiency  

NASA Astrophysics Data System (ADS)

In the current work, we report a series of bifacial dye-sensitized solar cells (DSSCs) that provide power conversion efficiencies of more than 10% from bifacial irradiation. The device comprises an N719-sensitized TiO2 anode, a transparent nickel selenide (Ni-Se) alloy counter electrode (CE), and liquid electrolyte containing I-/I3- redox couples. Because of the high optical transparency, electron conduction ability, electrocatalytic activity of Ni-Se CEs, as well as dye illumination, electron excitation and power conversion efficiency have been remarkably enhanced. Results indicate that incident light from a transparent CE has a compensation effect to the light from the anode. The impressive efficiency along with simple preparation of the cost-effective Ni-Se alloy CEs highlights the potential application of bifacial illumination technique in robust DSSCs.In the current work, we report a series of bifacial dye-sensitized solar cells (DSSCs) that provide power conversion efficiencies of more than 10% from bifacial irradiation. The device comprises an N719-sensitized TiO2 anode, a transparent nickel selenide (Ni-Se) alloy counter electrode (CE), and liquid electrolyte containing I-/I3- redox couples. Because of the high optical transparency, electron conduction ability, electrocatalytic activity of Ni-Se CEs, as well as dye illumination, electron excitation and power conversion efficiency have been remarkably enhanced. Results indicate that incident light from a transparent CE has a compensation effect to the light from the anode. The impressive efficiency along with simple preparation of the cost-effective Ni-Se alloy CEs highlights the potential application of bifacial illumination technique in robust DSSCs. Electronic supplementary information (ESI) available: Schematic diagram, repeated J-V curves, CV curves of Ni0.85Se electrode at various scan rates, relationship between peak current density and square root of scan rates. See DOI: 10.1039/c4nr03900a

Duan, Yanyan; Tang, Qunwei; He, Benlin; Li, Ru; Yu, Liangmin

2014-10-01

2

Transparent nickel selenide alloy counter electrodes for bifacial dye-sensitized solar cells exceeding 10% efficiency.  

PubMed

In the current work, we report a series of bifacial dye-sensitized solar cells (DSSCs) that provide power conversion efficiencies of more than 10% from bifacial irradiation. The device comprises an N719-sensitized TiO2 anode, a transparent nickel selenide (Ni-Se) alloy counter electrode (CE), and liquid electrolyte containing I(-)/I3(-) redox couples. Because of the high optical transparency, electron conduction ability, electrocatalytic activity of Ni-Se CEs, as well as dye illumination, electron excitation and power conversion efficiency have been remarkably enhanced. Results indicate that incident light from a transparent CE has a compensation effect to the light from the anode. The impressive efficiency along with simple preparation of the cost-effective Ni-Se alloy CEs highlights the potential application of bifacial illumination technique in robust DSSCs. PMID:25185939

Duan, Yanyan; Tang, Qunwei; He, Benlin; Li, Ru; Yu, Liangmin

2014-10-01

3

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

4

transparent electrode  

NASA Astrophysics Data System (ADS)

We report a new semitransparent inverted polymer solar cell (PSC) with a structure of glass/FTO/nc-TiO2/P3HT:PCBM/MoO3/Ag/MoO3. Because high-temperature annealing which decreased the conductivity of indium tin oxide (ITO) must be handled in the process of preparation of nanocrystalline titanium oxide (nc-TiO2), we replace glass/ITO with a glass/fluorine-doped tin oxide (FTO) substrate to improve the device performance. The experimental results show that the replacing FTO substrate enhances light transmittance between 400 and 600 nm and does not change sheet resistance after annealing treatment. The dependence of device performances on resistivity, light transmittance, and thickness of the MoO3/Ag/MoO3 film was investigated. High power conversion efficiency (PCE) was achieved for FTO substrate inverted PSCs, which showed about 75% increase compared to our previously reported ITO substrate device at different thicknesses of the MoO3/Ag/MoO3 transparent electrode films illuminated from the FTO side (bottom side) and about 150% increase illuminated from the MoO3/Ag/MoO3 side (top side).

Li, Fumin; Chen, Chong; Tan, Furui; Li, Chunxi; Yue, Gentian; Shen, Liang; Zhang, Weifeng

2014-10-01

5

An efficient and transparent copper sulfide nanosheet film counter electrode for bifacial quantum dot-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Copper sulfide (CuS) with nanosheet structure has been synthesized at a low temperature in situ on copper (Cu) film coated fluorine-doped tin oxide glass and bifacial quantum dot-sensitized solar cells (QDSSCs) were herein developed by using these CuS as counter electrodes (CEs). CuS is an environmental compatible and low toxic material. The obtained two-dimensional CuS nanosheet film presents high carrier mobility and exhibits highly catalytic performance for the polysulfide-based electrolyte. The QDSSC based on a CuS CE presents a power conversion efficiency (PCE) of 3.65% by optimizing the thickness of the Cu film under front illumination. The QDSSC based on a CuS CE prepared with a 200nm thick Cu film shows a very close PCE under front and rear illuminations in which the values are as high as 2.70% and 2.40%, respectively. All the PCEs of the CuS CEs are much higher than that of the Pt CE (1.34%).

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

2014-02-01

6

Fully solution-processed transparent conducting oxide-free counter electrodes for dye-sensitized solar cells: spray-coated single-wall carbon nanotube thin films loaded with chemically-reduced platinum nanoparticles.  

PubMed

We report fully solution-processed fabrication of transparent conducting oxide-free counter electrodes (CEs) for dye-sensitized solar cells (DSSCs) by combining spray-coating of single-wall carbon nanotubes (SWCNTs) and chemical reduction of chloroplatinic acid precursor to platinum nanoparticles (Pt NPs) with formic acid. The power conversion efficiency of a semitransparent DSSC with such SWCNT-based CE loaded with Pt NPs is comparable to that of a control device with a conventional CE. Quantification of Pt loading shows that network morphology of entangled SWCNTs is efficient in forming and retaining chemically reduced Pt NPs. Moreover, electron microscopy and electrochemical impedance spectroscopy results show that mainly Pt NPs, which are tens of nanometers in diameter and reside at the surface of SWCNT CEs, contribute to electrocatalytic activity for triiodide reduction, to which we attribute strong correlation between power conversion efficiency of DSSCs and time constant deduced from equivalent-circuit analysis of impedance spectra. PMID:25122074

Kim, Sang Yong; Kim, Yesel; Lee, Kyung Moon; Yoon, Woo Sug; Lee, Ho Seok; Lee, Jong Tae; Kim, Seung-Joo; Ahn, Yeong Hwan; Park, Ji-Yong; Lee, Tai Kyu; Lee, Soonil

2014-08-27

7

Optical impedance transformer for transparent conducting electrodes  

NASA Astrophysics Data System (ADS)

We present a practical and robust concept to bypass the typical trade-off between optical transparency and electrical conductivity of transparent conducting electrodes. A transparent conducting electrode serves to transmit photons and conduct electrons, and the frequencies of the corresponding optical and dc electric fields differ by at least 12 orders of magnitude. Therefore, we could engineer the optical electric field to influence the optical property, which is not intrinsic, of the transparent electrode without sacrificing its electrical performance. For a given light power input, the optical impedance transformer reduces the loss in a transparent electrode by raising the refractive index of its surrounding medium. The concept of optical impedance transformer can be realized by nanocone arrays, and we use it to design nanophotonic structures that provide broadband and omnidirectional reduction of optical loss in an ultrathin graphene electrode. In addition, the concept applies to thicker or nanostructured transparent electrodes. The results are verified against first-principles full-field electromagnetic simulations.

Wang, Ken X.; Piper, Jessica R.; Fan, Shanhui

2014-09-01

8

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

9

Performance dependence of Si quantum dot-sensitized solar cells on counter electrode  

NASA Astrophysics Data System (ADS)

Au counter electrode is generally used with polysulfide electrolyte for quantum dot-sensitized solar cells (QDSCs) due to degradation of QD by iodine electrolyte and strong interaction between Pt counter electrode and S2- ions in polysulfide electrolyte. In this work, the effects of the thickness and morphology of Au counter electrode on the performance of Si QDSC were investigated. Au film thickness was linearly controlled from 5 to 500 nm by deposition time. Cyclic voltammetry and impedance analysis clarified the catalytic activity of counter electrode, surface resistance of transparent conductive oxide (TCO), and the charge transportation at the counter electrode. The increase of Au film thickness reduced the surface resistance of TCO with increased conductivity. No significant difference in the redox reaction from electrolyte to Si QDs was observed for Au film thickness from 20 to 500 nm. Catalytic reaction of counter electrode was activated with the increase of Au film thickness up to 200 nm. The impedance of charge transportation at the counter electrode was also decreased with Au deposition. Their surface resistance, catalytic activity and internal resistance were reflected in overall performance. Consequently, Si QDSC with 200-nm-thick Au counter electrode had the best performance.

Seo, Hyunwoong; Ichida, Daiki; Uchida, Giichiro; Itagaki, Naho; Koga, Kazunori; Shiratani, Masaharu

2014-01-01

10

Photopatternable transparent conducting oxide nanoparticles for transparent electrodes.  

PubMed

We report a method to fabricate tailored transparent electrodes using photopatternable transparent conducting oxide nanoparticles (TCO NPs). We demonstrate solution-processed micropatterns by a conventional photolithography technique. We have synthesized indium tin oxide (ITO) NPs and functionalized them with a photolabile group, such as t-butoxycarbonyl (t-BOC), which can be deprotected by a chemical amplification reaction in the solid state film. The chemical amplification reaction leads to a shortening of the ligand that changes the solubility of the resulting ITO films. This ligand shortening process also contributes to a reduction of the sheet resistance in the resulting photopatterned ITO films. Furthermore, we have demonstrated the general viability and strength of this approach by also photopatterning zinc oxide (ZnO) NPs. PMID:23339987

Kim, Won Jin; Kim, Sung Jin; Cartwright, Alexander N; Prasad, Paras N

2013-02-15

11

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 180and 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. PMID:23900572

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

12

A transparent electrode based on a metal nanotrough network  

E-print Network

and Yi Cui1,4 * Transparent conducting electrodes are essential components for numerous flexible suitability of our transparent conducting electrode by fabricating a flexible touch-screen device polymers6 , carbon nanotubes7­9 and graphene10­12 . However, although flexibility is greatly improved

Cui, Yi

13

CdSe quantum dot-sensitized solar cell employing TiO2 nanotube working-electrode and Cu2S counter-electrode  

NASA Astrophysics Data System (ADS)

We proposed a CdSe quantum dot (QD)-sensitized solar cell (QDSSC), which is constructed with a CdSe QD adsorbed TiO2 nanotube working electrode on a Ti substrate, a ring shaped Cu2S counter electrode, prepared on a brass substrate having a glass window, and polysulfide electrolyte. The light was incident from the counter electrode. An incident photon to current conversion efficiency as high as 65% and a photovoltaic conversion efficiency as high as 1.8% under one sun have been achieved. We have demonstrated less costly QDSSC, without the requirement for both a transparent conductive electrode or a platinum film.

Shen, Qing; Yamada, Akari; Tamura, Satoru; Toyoda, Taro

2010-09-01

14

Nitrogen Doped Multi-Walled Carbon Nanotubes as Counter Electrodes in Dye Sensitized Solar Cells  

NASA Astrophysics Data System (ADS)

Dye-sensitized solar cells (DSSC) are an electrochemical solar cell based upon an iodide/triiodide redox couple mediating between a photosensitive electrode of a high bandgap semiconductor material stained with a photosensitive dye and a catalytic counter electrode. The standard counter electrode used in these dye solar cells has a function of reducing the triiodide back to iodide, and is composed of thermally decomposed platinum upon a transparent conductive oxide surface, generally Indium Tin Oxide (ITO) or Fluorinated Tin Oxide (FTO). While the highest performances found for DSSCs all use this platinum counter electrode, it is an undesirable material to use for scale production. The most common substitute materials are all based around carbon based materials. Carbon nanotubes have been applied to the DSSC counter electrode, with good success, where the defect sites of the carbon nanotubes offering sites for reduction of the triiodide. In this work, we investigated the use of nitrogen doped carbon noantubes, where the carbon atoms next to the nitrogen doping atoms have a higher positive charge density counter balancing the electron affinity of the nitrogen act as reduction sites as well, with electrochemical characterization describing the reduction in the charge transfer resistance from this doping scheme.

Velten, Josef; Lepro-Chavez, Xavier; Kuanyshbekova, Zharkynay; Bykova, Julia; Zakhidov, Anvar

2012-02-01

15

Copper nanowire arrays for transparent electrodes  

NASA Astrophysics Data System (ADS)

Metallic nanowires have demonstrated high optical transmission and electrical conductivity with potential for application as transparent electrodes that may be used in flexible devices. In this paper, we systematically investigated the electrical and optical properties of 1D and 2D copper nanowire (Cu NW) arrays as a function of diameter and pitch and compared their performance to that of Cu thin films and our recent results on silver (Ag) NW arrays. Cu NWs exhibit enhanced transmission over thin films due to propagating resonance modes between NWs. For the same geometry, the transmission of Cu NW arrays is about the same as that of Ag NW arrays since the dispersion relation of propagating modes in metal nanowire arrays are independent of the metal permittivity. The sheet resistance is also comparable since the conductivity of Cu is about the same as that of Ag. Just as in Ag NWs, larger Cu NW diameters and pitches are favored for achieving higher solar transmission at a particular sheet resistance. Cu NW arrays may achieve solar transmission >90% with sheet resistances <10 ?/sq and figure of merit ?DC/?op>1000. One of the primary concerns with the use of Cu is oxidation and we also investigated the impact of a nickel (Ni) coating, which can serve as an anti-oxidation layer, on the electrical and optical properties.

Gao, Tongchuan; Leu, Paul W.

2013-08-01

16

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

17

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. PMID:23680014

2013-01-01

18

Failure of silver nanowire transparent electrodes under current flow.  

PubMed

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. PMID:23680014

Khaligh, Hadi Hosseinzadeh; Goldthorpe, Irene A

2013-01-01

19

A transparent electrode based on a metal nanotrough network  

NASA Astrophysics Data System (ADS)

Transparent conducting electrodes are essential components for numerous flexible optoelectronic devices, including touch screens and interactive electronics. Thin films of indium tin oxide--the prototypical transparent electrode material--demonstrate excellent electronic performances, but film brittleness, low infrared transmittance and low abundance limit suitability for certain industrial applications. Alternatives to indium tin oxide have recently been reported and include conducting polymers, carbon nanotubes and graphene. However, although flexibility is greatly improved, the optoelectronic performance of these carbon-based materials is limited by low conductivity. Other examples include metal nanowire-based electrodes, which can achieve sheet resistances of less than 10? ?-1 at 90% transmission because of the high conductivity of the metals. To achieve these performances, however, metal nanowires must be defect-free, have conductivities close to their values in bulk, be as long as possible to minimize the number of wire-to-wire junctions, and exhibit small junction resistance. Here, we present a facile fabrication process that allows us to satisfy all these requirements and fabricate a new kind of transparent conducting electrode that exhibits both superior optoelectronic performances (sheet resistance of ~2? ?-1 at 90% transmission) and remarkable mechanical flexibility under both stretching and bending stresses. The electrode is composed of a free-standing metallic nanotrough network and is produced with a process involving electrospinning and metal deposition. We demonstrate the practical suitability of our transparent conducting electrode by fabricating a flexible touch-screen device and a transparent conducting tape.

Wu, Hui; Kong, Desheng; Ruan, Zhichao; Hsu, Po-Chun; Wang, Shuang; Yu, Zongfu; Carney, Thomas J.; Hu, Liangbing; Fan, Shanhui; Cui, Yi

2013-06-01

20

A transparent electrode based on a metal nanotrough network.  

PubMed

Transparent conducting electrodes are essential components for numerous flexible optoelectronic devices, including touch screens and interactive electronics. Thin films of indium tin oxide-the prototypical transparent electrode material-demonstrate excellent electronic performances, but film brittleness, low infrared transmittance and low abundance limit suitability for certain industrial applications. Alternatives to indium tin oxide have recently been reported and include conducting polymers, carbon nanotubes and graphene. However, although flexibility is greatly improved, the optoelectronic performance of these carbon-based materials is limited by low conductivity. Other examples include metal nanowire-based electrodes, which can achieve sheet resistances of less than 10? ?(-1) at 90% transmission because of the high conductivity of the metals. To achieve these performances, however, metal nanowires must be defect-free, have conductivities close to their values in bulk, be as long as possible to minimize the number of wire-to-wire junctions, and exhibit small junction resistance. Here, we present a facile fabrication process that allows us to satisfy all these requirements and fabricate a new kind of transparent conducting electrode that exhibits both superior optoelectronic performances (sheet resistance of ~2? ?(-1) at 90% transmission) and remarkable mechanical flexibility under both stretching and bending stresses. The electrode is composed of a free-standing metallic nanotrough network and is produced with a process involving electrospinning and metal deposition. We demonstrate the practical suitability of our transparent conducting electrode by fabricating a flexible touch-screen device and a transparent conducting tape. PMID:23685985

Wu, Hui; Kong, Desheng; Ruan, Zhichao; Hsu, Po-Chun; Wang, Shuang; Yu, Zongfu; Carney, Thomas J; Hu, Liangbing; Fan, Shanhui; Cui, Yi

2013-06-01

21

High-performance carbon counter electrode for dye-sensitized solar cells  

Microsoft Academic Search

Here, we reported that a new carbon electrode prepared with an activated carbon was superior to a Pt sputtered electrode as the counter electrode of dye-sensitized solar cells. The photovoltaic performance was largely influenced by the roughness factor of carbon electrode. The open-circuit voltage increased by about 60mV using the carbon counter electrode compared to the Pt counter electrode because

Kiyoaki Imoto; Kohshin Takahashi; Takahiro Yamaguchi; Teruhisa Komura; Jun-ichi Nakamura; Kazuhiko Murata

2003-01-01

22

Surface-plasmon enhanced transparent electrodes in organic photovoltaics  

NASA Astrophysics Data System (ADS)

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 92nm 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, Thomas H.; van de Lagemaat, Jao; Tenent, Robert C.; Morfa, Anthony J.; Rowlen, Kathy L.

2008-06-01

23

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

24

CZTS thin films on transparent conducting electrodes by electrochemical technique  

Microsoft Academic Search

We have fabricated single phase Cu2ZnSnS4 (CZTS) films using a specially designed 3-stage electrochemical system. Sequential electrodepositon of constituent metallic layers was carried out on SnO2\\/F coated glass substrates using a platinum counter electrode and a saturated calomel reference electrode. Unique bath compositions were formulated for each of these constituents. Sequentially deposited tri-layer stacks were annealed in sulfur environment to

Prashant K. Sarswat; Michael Snure; Michael L. Free; Ashutosh Tiwari

25

Catoptric electrodes: transparent metal electrodes using shaped surfaces.  

PubMed

An optical electrode design is presented that theoretically allows 100% optical transmission through an interdigitated metallic electrode at 50% metal areal coverage. This is achieved by redirection of light incident on embedded metal electrode lines to an angle beyond that required for total internal reflection. Full-field electromagnetic simulations using realistic material parameters demonstrate 84% frequency-averaged transmission for unpolarized illumination across the entire visible spectral range using a silver interdigitated electrode at 50% areal coverage. The redirection is achieved through specular reflection, making it nonresonant and arbitrarily broadband, provided the electrode width exceeds the optical wavelength. These findings could significantly improve the performance of photovoltaic devices and optical detectors that require high-conductivity top contacts. PMID:25166087

Kik, Pieter G

2014-09-01

26

TCO/Ag/TCO transparent electrodes for solar cells application  

NASA Astrophysics Data System (ADS)

Among transparent electrodes, transparent conductive oxides (TCO)/metal/TCO structures can achieve optical and electrical performances comparable to, or better than, single TCO layers and very thin metallic films. In this work, we report on thin multilayers based on aluminum zinc oxide (AZO), indium tin oxide (ITO) and Ag deposited by RF magnetron sputtering on soda lime glass at room temperature. The TCO/Ag/TCO structures with thicknesses of about 50/10/50 nm were deposited with all combinations of AZO and ITO as top and bottom layers. While the electrical conductivity is dominated by the Ag intralayer irrespective of the TCO nature, the optical transmissions show a dependence on the nature of the top and bottom TCOs, mainly due to the change in the reflectivity of the multilayers. Structural, electrical and optical properties are studied to optimize the structure for very thin transparent electrodes suitable for photovoltaic applications.

Boscarino, S.; Crupi, I.; Mirabella, S.; Simone, F.; Terrasi, A.

2014-09-01

27

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 7nm and the maximum peak-to-valley value is 30nm, 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. PMID:24994963

2014-01-01

28

Improved thermal oxidation stability of solution-processable silver nanowire transparent electrode by reduced graphene oxide.  

PubMed

Solution-processable silver nanowire-reduced graphene oxide (AgNW-rGO) hybrid transparent electrode was prepared in order to replace conventional ITO transparent electrode. AgNW-rGO hybrid transparent electrode exhibited high optical transmittance and low sheet resistance, which is comparable to ITO transparent electrode. In addition, it was found that AgNW-rGO hybrid transparent electrode exhibited highly enhanced thermal oxidation and chemical stabilities due to excellent gas-barrier property of rGO passivation layer onto AgNW film. Furthermore, the organic solar cells with AgNW-rGO hybrid transparent electrode showed good photovoltaic behavior as much as solar cells with AgNW transparent electrode. It is expected that AgNW-rGO hybrid transparent electrode can be used as a key component in various optoelectronic application such as display panels, touch screen panels, and solar cells. PMID:23206541

Ahn, Yumi; Jeong, Youngjun; Lee, Youngu

2012-12-01

29

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

30

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

31

Topological insulator nanostructures for near-infrared transparent flexible electrodes.  

PubMed

Topological insulators are an intriguing class of materials with an insulating bulk state and gapless Dirac-type edge/surface states. Recent theoretical work predicts that few-layer topological insulators are promising candidates for broadband and high-performance optoelectronic devices due to their spin-momentum-locked massless Dirac edge/surface states, which are topologically protected against all time-reversal-invariant perturbations. Here, we present the first experimental demonstration of near-infrared transparent flexible electrodes based on few-layer topological-insulator Bi(2)Se(3) nanostructures epitaxially grown on mica substrates by means of van der Waals epitaxy. The large, continuous, Bi(2)Se(3)-nanosheet transparent electrodes have single Dirac cone surface states, and exhibit sheet resistances as low as ~330 ? per square, with a transparency of more than 70% over a wide range of wavelengths. Furthermore, Bi(2)Se(3)-nanosheet transparent electrodes show high chemical and thermal stabilities as well as excellent mechanical durability, which may lead to novel optoelectronic devices with unique properties. PMID:22437712

Peng, Hailin; Dang, Wenhui; Cao, Jie; Chen, Yulin; Wu, Di; Zheng, Wenshan; Li, Hui; Shen, Zhi-Xun; Liu, Zhongfan

2012-04-01

32

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

33

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

34

Surface-plasmon enhanced transparent electrodes in organic photovoltaics  

Microsoft Academic Search

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

Thomas H. Reilly; Jao van de Lagemaat; Robert C. Tenent; Anthony J. Morfa; Kathy L. Rowlen

2008-01-01

35

Double-layer CVD graphene as stretchable transparent electrodes  

NASA Astrophysics Data System (ADS)

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.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. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00265b

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

2014-05-01

36

Electrically modulated attachment and detachment of animal cells cultured on an optically transparent patterning electrode.  

PubMed

The purpose of this study was to develop the modulation methods for the attachment and detachment of specifically positioned adhesive animal cells cultured on an electrode surface with the application of a weak electrical potential. A patterned indium tin oxide (ITO) optically transparent working electrode was placed on the bottom of a chamber slide with a counter-(Pt) and reference (Ag/AgCl) electrode. The ITO patterning was formed by a reticulate ITO region and arrayed square glass regions of varying size. Using the 3-electrode culture system, the author succeeded in modulation of the attachment and detachment of animal cells on the working electrode surface. Animal cells suspended in serum or sera containing medium were drawn to and attached on a reticulate ITO electrode region to which a +0.4-V vs. Ag/AgCl-positive potential was applied. Meanwhile, the cells were successfully placed on the square glass regions by -0.3-V vs. Ag/AgCl-negative potential application. Animal cells were detached not only from the ITO electrode but also from the square glass regions after the application of a 10-mV vs. Ag/AgCl, 9-MHz [corrected] rectangular wave potential in PBS(-) for 30-60 min. Rectangular wave potential-induced cell detachment is almost completely noncytotoxic, and no statistical differences between trypsinization and the high frequency wave potential application were observed in HeLa cell growth. The electrical modulation of the specifically positioned cell attachment and detachment techniques holds potential for novel optical microscopic cell sorting analysis in lab-on-chip devices. PMID:21277827

Koyama, Sumihiro

2011-05-01

37

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

38

Rational screening low-cost counter electrodes for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Dye-sensitized solar cells have attracted intense research attention owing to their ease of fabrication, cost-effectiveness and high efficiency in converting solar energy. Noble platinum is generally used as catalytic counter electrode for redox mediators in electrolyte solution. Unfortunately, platinum is expensive and non-sustainable for long-term applications. Therefore, researchers are facing with the challenge of developing low-cost and earth-abundant alternatives. So far, rational screening of non-platinum counter electrodes has been hamstrung by the lack of understanding about the electrocatalytic process of redox mediators on various counter electrodes. Here, using first-principle quantum chemical calculations, we studied the electrocatalytic process of redox mediators and predicted electrocatalytic activity of potential semiconductor counter electrodes. On the basis of theoretical predictions, we successfully used rust (?-Fe2O3) as a new counter electrode catalyst, which demonstrates promising electrocatalytic activity towards triiodide reduction at a rate comparable to platinum.

Hou, Yu; Wang, Dong; Yang, Xiao Hua; Fang, Wen Qi; Zhang, Bo; Wang, Hai Feng; Lu, Guan Zhong; Hu, P.; Zhao, Hui Jun; Yang, Hua Gui

2013-03-01

39

Organic electro-optic modulator using transparent conducting oxides as electrodes  

E-print Network

Organic electro-optic modulator using transparent conducting oxides as electrodes Guoyang Xu, Zhifu: A novel organic electro-optic (EO) modulator using transparent conducting oxides (ZnO and In2O3 using ion- beam assisted deposition. The top electrode is directly deposited on the guest-host organic

Ho, Seng-Tiong

40

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

41

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. PMID:24763248

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

42

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

PubMed

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. PMID:24763248

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

43

Fabrication of high performance Pt counter electrodes on conductive plastic substrate for flexible dye-sensitized solar cells  

Microsoft Academic Search

Pt counter electrodes (CEs) with different platinum loading have been prepared using chemical reduced method on flexible indium-doped tin oxide coated polyethylene naphthalate (ITO-PEN) for dye-sensitized solar cells (DSSCs). H2PtCl66H2O terpineol solutions were screen printed on the transparent ITO-PEN substrates. After drying, H2PtCl6 was reduced by treating it in NaBH4 solution followed by the hydrothermal treatment at 100C. The obtained

Lili Chen; Weiwei Tan; Jingbo Zhang; Xiaowen Zhou; Xiaoling Zhang; Yuan Lin

2010-01-01

44

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

PubMed Central

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. PMID:22650906

2012-01-01

45

Low-Cost Flexible Nano-Sulfide/Carbon Composite Counter Electrode for Quantum-Dot-Sensitized Solar Cell  

NASA Astrophysics Data System (ADS)

Cu2S nanocrystal particles were in situ deposited on graphite paper to prepare nano-sulfide/carbon composite counter electrode for CdS/CdSe quantum-dot-sensitized solar cell (QDSC). By optimization of deposition time, photovoltaic conversion efficiency up to 3.08% was obtained. In the meantime, this composite counter electrode was superior to the commonly used Pt, Au and carbon counter electrodes. Electrochemical impedance spectra further confirmed that low charge transfer resistance at counter electrode/electrolyte interface was responsible for this, implied the potential application of this composite counter electrode in high-efficiency QDSC.

Deng, Minghui; Zhang, Quanxin; Huang, Shuqing; Li, Dongmei; Luo, Yanhong; Shen, Qing; Toyoda, Taro; Meng, Qingbo

2010-06-01

46

Polymer-assisted direct deposition of uniform carbon nanotube bundle networks for high performance transparent electrodes.  

PubMed

Flexible transparent electrodes are crucial for touch screen, flat panel display, and solar cell technologies. While carbon nanotube network electrodes show promise, characteristically poor dispersion properties have limited their practicality. We report that addition of small amounts of conjugated polymer to nanotube dispersions enables straightforward fabrication of uniform network electrodes by spin-coating and simultaneous tuning of parameters such as bundle size and density. After treatment in thionyl chloride, electrodes have sheet resistances competitive with other reported carbon nanotube based transparent electrodes to date. PMID:19422197

Hellstrom, Sondra L; Lee, Hang Woo; Bao, Zhenan

2009-06-23

47

Past achievements and future challenges in the development of optically transparent electrodes  

NASA Astrophysics Data System (ADS)

Transparent conductive electrodes play important roles in information and energy technologies. These materials, particularly transparent conductive oxides, are widely used as transparent electrodes across technical fields such as low-emissivity coatings, flat-panel displays, thin-film solar cells and organic light-emitting diodes. This Review begins by summarizing the properties and applications of transparent conductive oxides such as In2O3, SnO2, ZnO and TiO2. Owing to the increasing demand for raw materials -- especially indium -- scientists are currently searching for alternatives to indium tin oxide. Carbon nanotube and metal nanowire networks, as well as regular metal grids, have been investigated for use as transparent conductive electrodes. This Review compares these materials and the recently 'rediscovered' graphene with today's established transparent conductive oxides.

Ellmer, Klaus

2012-12-01

48

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

49

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

50

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

2014-05-01

51

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

52

Synthesis of mono-to-multi-layer graphene for transparent electrode applications  

E-print Network

In this thesis, mono-to-multilayer graphene for transparent electrode applications was synthesized by Atmospheric Pressure Chemical Vapor Deposition (APCVD) and the key factors that determine the electrical and optical ...

Choi, Minseok

2012-01-01

53

Preparation and properties of low-cost graphene counter electrodes for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

With the advantages of excellent electrical properties, high catalytic activity and low-cost preparation, Graphene is one of the most expected carbon materials to replace the expensive Pt as counter electrodes for dye-sensitized solar cells (DSSCs). In this paper, graphene counter electrodes were obtained by simple doctor-blade coating method on fluorine tin oxides (FTOs). The samples were investigated by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscope (SEM). Then the low-cost graphene electrodes were applied in typical sandwich-type DSSCs with TiO2 or ZnO as photoanodes, and their photoelectric conversion efficiency (?) were about 4.34% and 2.28%, respectively, which were a little lower than those of Pt electrodes but much higher than those of graphite electrodes. This law was consistent with the test results of electrochemical impedance spectroscopy (EIS). Low-cost graphene electrodes can be applied in DSSCs by process optimization.

Wu, Qishuang; Shen, Yue; Wang, Qiandi; Gu, Feng; Cao, Meng; Wang, Linjun

2013-12-01

54

Vapor phase polymerization of poly (3,4-ethylenedioxythiophene) on flexible substrates for enhanced transparent electrodes  

Microsoft Academic Search

Recently, conducting polymer thin films have been investigated as transparent electrodes in photovoltaic devices and organic light emitting diodes. Due to its relatively high conductivity and excellent transmission in the visible region, poly (3, 4-ethyelenedioxythiophene) (PEDOT) has been shown to be a viable option for such applications. Herein described is a method for the vapor phase polymerization (VPP) of transparent

Christopher M. Madl; Peter N. Kariuki; Jessica Gendron; Louis F. J. Piper; Wayne E. Jones

2011-01-01

55

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

56

Dye-sensitized solar cell with a titanium-oxide-modified carbon nanotube transparent electrode  

E-print Network

reaction limits their application as a working electrode in a liquid-type dye-sensitized solar cell (DSSC that facilitates the unidirectional flow of electrons in the cell without sacrificing the electrical and opticalDye-sensitized solar cell with a titanium-oxide-modified carbon nanotube transparent electrode A. K

Demir, Hilmi Volkan

57

Metal-mesh based transparent electrode on a 3-D curved surface by electrohydrodynamic jet printing  

NASA Astrophysics Data System (ADS)

Invisible Ag mesh transparent electrodes (TEs), with a width of 7??m, were prepared on a curved glass surface by electrohydrodynamic (EHD) jet printing. With a 100??m pitch, the EHD jet printed the Ag mesh on the convex glass which had a sheet resistance of 1.49??/?. The printing speed was 30?cm?s-1 using Ag ink, which had a 10?000 cPs viscosity and a 70?wt% Ag nanoparticle concentration. We further showed the performance of a 3-D transparent heater using the Ag mesh transparent electrode. The EHD jet printed an invisible Ag grid transparent electrode with good electrical and optical properties with promising applications on printed optoelectronic devices.

Seong, Baekhoon; Yoo, Hyunwoong; Dat Nguyen, Vu; Jang, Yonghee; Ryu, Changkook; Byun, Doyoung

2014-09-01

58

Impact of transparent electrode on photoresponse of ZnO-based phototransistor  

SciTech Connect

ZnO-based photo-thin film transistors with enhanced photoresponse were developed using transparent conductive oxide contacts. Changing the electrode from opaque Mo to transparent In-Zn-O increases the photocurrent by five orders of magnitude. By changing the opacity of each source and drain electrode, we could observe how the photoresponse is affected. We deduce that the photocurrent generation mechanism is based on an energy band change due to the photon irradiation. More importantly, we reveal that the photocurrent is determined by the energy barrier of injected electrons at the interface between the source electrode and the active layer.

Lee, Seunghyup; Ahn, Seung-Eon, E-mail: seungeon.ahn@samsung.com; Jeon, Yongwoo; Ahn, Ji-Hoon; Song, Ihun; Kim, Jungwoo; Choi, Hyung; Chung, U-in; Park, Jaechul [Advanced Device Laboratory, Samsung Advanced Institute of Technology, Samsung Electronics Corporation, Yongin-Si, Gyeonggi-Do 446-712 (Korea, Republic of)] [Advanced Device Laboratory, Samsung Advanced Institute of Technology, Samsung Electronics Corporation, Yongin-Si, Gyeonggi-Do 446-712 (Korea, Republic of); Jeon, Sanghun [Department of Display and Semiconductor Physics and Department of Applied Physics, Korea University, 2511, Sejongro, Sejong, 339700 (Korea, Republic of)] [Department of Display and Semiconductor Physics and Department of Applied Physics, Korea University, 2511, Sejongro, Sejong, 339700 (Korea, Republic of); Yun, Dong-Jin [Analytical Science Group, Samsung Advanced Institute of Technology, Samsung Electronics Corporation, Yongin-Si, Gyeonggi-Do 446-712 (Korea, Republic of)] [Analytical Science Group, Samsung Advanced Institute of Technology, Samsung Electronics Corporation, Yongin-Si, Gyeonggi-Do 446-712 (Korea, Republic of)

2013-12-16

59

Dye-sensitized solar cell with a titanium-oxide-modified carbon nanotube transparent electrode  

NASA Astrophysics Data System (ADS)

Transparent and conductive carbon-based materials are promising for window electrodes in solid-state optoelectronic devices. However, the catalytic activity to redox reaction limits their application as a working electrode in a liquid-type dye-sensitized solar cell (DSSC). In this letter, we propose and demonstrate a transparent carbon nanotubes (CNTs) film as the working electrode in a DSSC containing iodide/triiodide redox couples. This implementation is realized by inhibiting the charge-transfer kinetics at CNT/redox solution interface with an aid of thin titanium oxide film that facilitates the unidirectional flow of electrons in the cell without sacrificing the electrical and optical properties of CNT.

Kyaw, A. K. K.; Tantang, H.; Wu, T.; Ke, L.; Peh, C.; Huang, Z. H.; Zeng, X. T.; Demir, H. V.; Zhang, Q.; Sun, X. W.

2011-07-01

60

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. PMID:22221501

2012-01-01

61

Versatile Multilayer Transparent Electrodes for ITO-Free and Flexible Organic Solar Cells  

Microsoft Academic Search

Multilayer transparent electrodes based on a dielectric-metal-dielectric structure are explored as an effective alternative to indium tin oxide (ITO) electrodes that can lead to ITO-free or highly flexible organic photovoltaic (OPV) cells with a performance comparable to conventional cells. The role of each layer in multilayer electrodes is discussed with an emphasis on the potential role of inner dielectric layer

Seungchan Han; Sooyeon Lim; Hoyeon Kim; Hyunsu Cho; Seunghyup Yoo

2010-01-01

62

Rare-metal-free flexible counter electrodes for dye-sensitized solar-cells produced using wet processes only.  

PubMed

Dye-sensitized solar-cells (DSCs) are cheap because they are produced using low-cost materials and simple manufacturing processes. However, the substrates of DSC counter electrodes are sputtered with a transparent conductive oxide and platinum. This involves vacuum manufacturing processes and high-cost (rare-metal) materials, and increases the costs of DSCs. In this study, we used non-rare-metal low-cost materials and simple wet processes, using combined poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) and Ag network (Ag NW) substrates. To solve the problem of Ag NW corrosion by the iodine electrolyte, we hot-pressed the Ag NW substrate and covered with a PEDOT/PSS layer as a barrier against iodine. The PEDOT/PSS layer acted as a catalyst and cells using an Ag NW covered with PEDOT/PSS generated electricity with illumination from both sides. The cell performance was improved by using a PEDOT/PSS layer containing 20 wt % TiO2 nanoparticles (NPs). The performance of the DSSC cell with an Ag NW substrate covered with a PEDOT/PSS layer containing TiO2 NPs (5.13%) was higher than that of a cell using an indium tin oxide substrate covered with the same layer (4.91%). These values are very similar to those of cells using a platinum counter electrode (5.36%). This research showed the possibility of replacing conventional high-cost counter electrodes with low-cost materials, and using only simple wet processes. PMID:23566351

Okada, Issei; Shiratori, Seimei

2013-05-22

63

Transparent and flexible low noise graphene electrodes for simultaneous electrophysiology and neuroimaging.  

PubMed

Calcium imaging is a versatile experimental approach capable of resolving single neurons with single-cell spatial resolution in the brain. Electrophysiological recordings provide high temporal, but limited spatial resolution, because of the geometrical inaccessibility of the brain. An approach that integrates the advantages of both techniques could provide new insights into functions of neural circuits. Here, we report a transparent, flexible neural electrode technology based on graphene, which enables simultaneous optical imaging and electrophysiological recording. We demonstrate that hippocampal slices can be imaged through transparent graphene electrodes by both confocal and two-photon microscopy without causing any light-induced artefacts in the electrical recordings. Graphene electrodes record high-frequency bursting activity and slow synaptic potentials that are hard to resolve by multicellular calcium imaging. This transparent electrode technology may pave the way for high spatio-temporal resolution electro-optic mapping of the dynamic neuronal activity. PMID:25327632

Kuzum, Duygu; Takano, Hajime; Shim, Euijae; Reed, Jason C; Juul, Halvor; Richardson, Andrew G; de Vries, Julius; Bink, Hank; Dichter, Marc A; Lucas, Timothy H; Coulter, Douglas A; Cubukcu, Ertugrul; Litt, Brian

2014-01-01

64

Efficient dye-sensitized solar cells with catalytic multiwall carbon nanotube counter electrodes.  

PubMed

We report the successful application of multiwall carbon nanotubes (CNTs) as electrocatalysts for triiodide reduction in a dye-sensitized solar cell (DSSC). Defect-rich edge planes of bamboolike-structure multiwall CNTs facilitate the electron-transfer kinetics at the counter electrode-electrolyte interface, resulting in low charge-transfer resistance and an improved fill factor. In combination with a dye-sensitized TiO2 photoanode and an organic liquid electrolyte, a multiwall CNT counter-electrode DSSC shows 7.7% energy conversion efficiency under 1 sun illumination (100 mW/cm(2), air mass 1.5 G). The short-term stability test at moderate conditions confirms the robustness of CNT counter-electrode DSSCs. PMID:20355903

Lee, Won Jae; Ramasamy, Easwaramoorthi; Lee, Dong Yoon; Song, Jae Sung

2009-06-01

65

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

66

Investigation of chemically synthesized graphene as counter electrode for dye sensitized solar cells  

NASA Astrophysics Data System (ADS)

Graphene was synthesized and used as a counter electrode in place of platinum in dye sensitized solar cells. This study reveals that the graphene synthesized by reduction of graphene oxide still contains functional groups even after reduction. The synthesized graphene counter electrodes were prepared by screen printing fabrication techniques. The influence of temperature variation on the films morphology, crystallinity, and its interfacial adhesiveness to the fluorine doped tin oxide coated glass were studied. Screen printing technique has shown uniform surface, decreased agglomeration of nanoparticles and high film adhesiveness. The screen printed film annealed at 400C reveals best surface morphology.

Prakash, Shejale Kiran; Sharma, Rakesh K.; Roy, Mahesh S.; Kumar, Mahesh

2014-10-01

67

Carbon coated stainless steel as counter electrode for dye sensitized solar cells  

NASA Astrophysics Data System (ADS)

A new type of counter electrode for dye sensitized solar cells has been fabricated using a stainless steel sheet as substrate and graphite, graphene and multiwall carbon nanotubes as the catalytic material which applied by screen printing technique. The sheet resistances of the substrates and there influence on the dye sensitized solar cells has been studied. The fabricated counter electrodes i.e. SS-graphite, SS-graphene SS-MWCNT and SS-platinum were tested for their photovoltaic response in the form of dye sensitized solar cells.

Prakash, Shejale Kiran; Sharma, Rakesh K.; Roy, Mahesh S.; Kumar, Mahesh

2014-10-01

68

Increase in the DSSC efficiency when using metal-coated carbon nanowall counter electrodes  

NASA Astrophysics Data System (ADS)

This research was conducted to improve the efficiency of dye-sensitized solar cells (DSSCs) using metal-layer-coated carbon nanowalls (CNWs) as counter electrodes. The CNWs were synthesized on a fluorine-doped tin-oxide (FTO) glass substrate in a microwave plasma-enhanced chemical vapor deposition (PECVD) system using methane (CH4), and the CNWS were sputter-coated with metal films several times by using an RF magnetron sputtering system and four-inch metal targets (Cu, W and Ni, separately). Then, the metal-layer-coated CNWs were used as counter electrodes for manufacturing the DSCCs. The vertical and the surface conditions of the metal-coated CNWs used as the DSCC electrodes were characterized by their electrical variations through field-emission scanning electron microscopy (FE-SEM) and Hall measurements. Their optical characteristics were analyzed using UV-Vis equipment, and the energy conversion efficiencies of the DSSCs manufactured using the metal-layer-coated CNWs as the counter electrodes were measured. The results confirmed that the efficiency improved when the W-coated CNW was used as the counter electrode.

Lee, Sangjoon; Choi, Won Seok; Lim, Dong-Gun; Choi, Eun Chang; Hong, Byungyou

2014-08-01

69

Carbon nanotube/graphene nanocomposite as efficient counter electrodes in dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

We demonstrated the replacement of the Pt catalyst normally used in the counter electrode of a dye-sensitized solar cell (DSSC) by a nanocomposite of dry spun carbon multi-walled nanotube (MWNT) sheets with graphene flakes (Gr-F). The effectiveness of this counter electrode on the reduction of the triiodide in the iodide/triiodide redox (I-/I3-) redox reaction was studied in parallel with the use of the dry spun carbon MWNT sheets alone and graphene flakes used independent of each other. This nanocomposite deposited onto fluorinated tin-oxide-coated glass showed improved catalytic behavior and power conversion efficiency (7.55%) beyond the use of the MWNTs alone (6.62%) or graphene alone (4.65%) for the triiodide reduction reaction in DSSC. We also compare the use of the carbon MWNT/Gr-F composite counter electrode with a DSSC using the standard Pt counter electrode (8.8%). The details of increased performance of graphene/MWNT composite electrodes as studied are discussed in terms of increased catalytic activity permitted by sharp atomic edges that arise from the structure of graphene flakes or the defect sites in the carbon MWNT and increased electrical conductivity between the carbon MWNT bundles by the graphene flakes.

Velten, Josef; Mozer, Attila J.; Li, Dan; Officer, David; Wallace, Gordon; Baughman, Ray; Zakhidov, Anvar

2012-03-01

70

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 0.0007 s(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 10 mA [42.8 mA cm(-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

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

2014-11-15

71

Molecular-Beam Epitaxial Growth of a Far-Infrared Transparent Electrode for Extrinsic Germanium Photoconductors  

NASA Astrophysics Data System (ADS)

We have evaluated the optical and electrical properties of a far-infrared (IR) transparent electrode for extrinsic germanium (Ge) photoconductors at 4 K, which was fabricated by molecular beam epitaxy (MBE). As a far-IR transparent electrode, an aluminum (Al)-doped Ge layer is formed at well-optimized doping concentration and layer thickness in terms of the three requirements: high far-IR transmittance, low-resistivity, and excellent ohmic contact. The Al-doped Ge layer has the far-IR transmittance of >95% within the wavelength range of 40--200 ?m, while low-resistivity (5 ? cm) and ohmic contact are ensured at 4 K. We demonstrate the applicability of the MBE technology in fabricating the far-IR transparent electrode satisfying the above requirements.

Suzuki, Toyoaki; Wada, Takehiko; Hirose, Kazuyuki; Makitsubo, Hironobu; Kaneda, Hidehiro

2012-08-01

72

High-Performance NiO/Ag/NiO Transparent Electrodes for Flexible Organic Photovoltaic Cells.  

PubMed

Transparent electrodes with a dielectric-metal-dielectric (DMD) structure can be implemented in a simple manufacturing process and have good optical and electrical properties. In this study, nickel oxide (NiO) is introduced into the DMD structure as a more appropriate dielectric material that has a high conduction band for electron blocking and a low valence band for efficient hole transport. The indium-free NiO/Ag/NiO (NAN) transparent electrode exhibits an adjustable high transmittance of ?82% combined with a low sheet resistance of ?7.6 ?sq(-1) and a work function of 5.3 eV after UVO treatment. The NAN electrode shows excellent surface morphology and good thermal, humidity, and environmental stabilities. Only a small change in sheet resistance can be found after NAN electrode is preserved in air for 1 year. The power conversion efficiencies of organic photovoltaic cells with NAN electrodes deposited on glass and polyethylene terephthalate (PET) substrates are 6.07 and 5.55%, respectively, which are competitive with those of indium tin oxide (ITO)-based devices. Good photoelectric properties, the low-cost material, and the room-temperature deposition process imply that NAN electrode is a striking candidate for low-cost and flexible transparent electrode for efficient flexible optoelectronic devices. PMID:25148532

Xue, Zhichao; Liu, Xingyuan; Zhang, Nan; Chen, Hong; Zheng, Xuanming; Wang, Haiyu; Guo, Xiaoyang

2014-09-24

73

Sub-micrometer-sized graphite as a conducting and catalytic counter electrode for dye-sensitized solar cells.  

PubMed

Sub-micrometer-sized colloidal graphite (CG) was tested as a conducting electrode to replace transparent conducting oxide (TCO) electrodes and as a catalytic material to replace platinum (Pt) for I(3)(-) reduction in dye-sensitized solar cell (DSSC). CG paste was used to make a film via the doctor-blade process. The 9 ?m thick CG film showed a lower resistivity (7 ?/?) than the widely used fluorine-doped tin oxide TCO (8-15 ?/?). The catalytic activity of this graphite film was measured and compared with the corresponding properties of Pt. Cyclic voltammetry and electrochemical impedance spectroscopy studies clearly showed a decrease in the charge transfer resistance with the increase in the thickness of the graphite layer from 3 to 9 ?m. Under 1 sun illumination (100 mW cm(-2), AM 1.5), DSSCs with submicrometer-sized graphite as a catalyst on fluorine-doped tin oxide TCO showed an energy conversion efficiency greater than 6.0%, comparable to the conversion efficiency of Pt. DSSCs with a graphite counter electrode (CE) on TCO-free bare glass showed an energy conversion efficiency greater than 5.0%, which demonstrated that the graphite layer could be used both as a conducting layer and as a catalytic layer. PMID:21351744

Veerappan, Ganapathy; Bojan, Karunagaran; Rhee, Shi-Woo

2011-03-01

74

Functionalized Graphene as a Catalytic Counter Electrode in Dye-Sensitized  

E-print Network

, since platinum is a precious metal, much incentive exists to develop DSSC counter electrodes using but typically requires a platinum catalyst in DSSC operation.3 5 Platinum has high catalytic activity toward I3 as potential catalysts for DSSC cathodes, due to graphene's exceptional surface area and conductivity.21 23

Aksay, Ilhan A.

75

Thermally exfoliated graphene based counter electrode for low cost dye sensitized solar cells  

SciTech Connect

Graphene obtained from thermal exfoliation of graphite oxide are highly wrinkled and have large surface area. Their wrinkled nature is expected to give them excellent catalytic activity. Herein, we demonstrate the use of thermally exfoliated graphene (TEG) as cost effective electrocatalyst for the tri-iodide reduction in dye sensitized solar cells (DSSCs). X-ray diffraction, Raman and Infra red spectroscopy and electron microscopy studies confirm the defective and wrinkled nature of TEG. BET surface area measurement show a large surface area of {approx} 470 m{sup 2}/g. The counter electrode was fabricated by drop casting a slurry of TEG dispersed in a Nafion:Ethanol solution on fluorine doped tin oxide (FTO) substrates. The use of Nafion prevented film ''peel off,'' thus ensuring a good substrate adhesion. Electrochemical impedance spectroscopy reveals that TEG had a catalytic performance comparable to that of Pt, suggesting its use as counter electrode material. As expected, the DSSC fabricated with Nafion solubilized TEG/FTO as counter electrode shows an efficiency of about 2.8%, comparable to Pt counter electrode based DSSC which has an efficiency of about 3.4%.

Kaniyoor, Adarsh; Ramaprabhu, Sundara [Alternative Energy and Nanotechnology Laboratory, Nano Functional Materials Technology Centre, Department of Physics, Indian Institute of Technology Madras, Chennai (India)

2011-06-15

76

Thermally exfoliated graphene based counter electrode for low cost dye sensitized solar cells  

NASA Astrophysics Data System (ADS)

Graphene obtained from thermal exfoliation of graphite oxide are highly wrinkled and have large surface area. Their wrinkled nature is expected to give them excellent catalytic activity. Herein, we demonstrate the use of thermally exfoliated graphene (TEG) as cost effective electrocatalyst for the tri-iodide reduction in dye sensitized solar cells (DSSCs). X-ray diffraction, Raman and Infra red spectroscopy and electron microscopy studies confirm the defective and wrinkled nature of TEG. BET surface area measurement show a large surface area of 470 m2/g. The counter electrode was fabricated by drop casting a slurry of TEG dispersed in a Nafion:Ethanol solution on fluorine doped tin oxide (FTO) substrates. The use of Nafion prevented film "peel off," thus ensuring a good substrate adhesion. Electrochemical impedance spectroscopy reveals that TEG had a catalytic performance comparable to that of Pt, suggesting its use as counter electrode material. As expected, the DSSC fabricated with Nafion solubilized TEG/FTO as counter electrode shows an efficiency of about 2.8%, comparable to Pt counter electrode based DSSC which has an efficiency of about 3.4%.

Kaniyoor, Adarsh; Ramaprabhu, Sundara

2011-06-01

77

CdSe quantum dot-sensitized solar cell employing TiO2 nanotube working-electrode and Cu2S counter-electrode  

Microsoft Academic Search

We proposed a CdSe quantum dot (QD)-sensitized solar cell (QDSSC), which is constructed with a CdSe QD adsorbed TiO2 nanotube working electrode on a Ti substrate, a ring shaped Cu2S counter electrode, prepared on a brass substrate having a glass window, and polysulfide electrolyte. The light was incident from the counter electrode. An incident photon to current conversion efficiency as

Qing Shen; Akari Yamada; Satoru Tamura; Taro Toyoda

2010-01-01

78

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

79

Au@MnO2 Core-Shell Nanomesh Electrodes for Transparent Flexible Supercapacitors.  

PubMed

A novel Au@MnO2 supercapacitor is presented. The sophisticated core-shell architecture combining an Au nanomesh core with a MnO2 shell on a flexible polymeric substrate is demonstrated as an electrode for high performance transparent flexible supercapacitors (TFSCs). Due to their unique structure, high areal/gravimetric capacitance and rate capability for TFSCs are achieved. PMID:24976434

Qiu, Tengfei; Luo, Bin; Giersig, Michael; Akinoglu, Eser Metin; Hao, Long; Wang, Xiangjun; Shi, Lin; Jin, Meihua; Zhi, Linjie

2014-10-01

80

Transparent conductive oxide electrode dependence of photocurrent characteristics in bacteriorhodopsin photocells  

NASA Astrophysics Data System (ADS)

We investigated the photocurrent characteristics in photocells using bacteriorhodopsin (bR) thin films deposited on various kinds of transparent conductive oxide (TCO) electrodes. The photocurrent depends largely on the species of TCO and partly on the surface morphology. The photocell using a bR thin film deposited on a fluorine-doped tin oxide electrode with a textured structure showed the largest photocurrent. Our results indicate that the variation of capacitance near the interface induced by the bR's light-driven proton pump function affects the transient photocurrent, while the capacitance near the interface is produced by the TCO electrode, bR thin film, and electrolyte solution.

Yamada, Toshiki; Haruyama, Yoshihiro; Kasai, Katsuyuki; Kaji, Takahiro; Tominari, Yukihiro; Tanaka, Shukichi; Otomo, Akira

2014-11-01

81

Flexible organic light-emitting devices with a smooth and transparent silver nanowire electrode  

NASA Astrophysics Data System (ADS)

We demonstrate a flexible organic light-emitting device (OLED) by using silver nanowire (AgNW) transparent electrode. A template stripping process has been employed to fabricate the AgNW electrode on a photopolymer substrate. From this approach, a random AgNW network electrode can be transferred to the flexible substrate and its roughness has been successfully decreased. As a result, the devices obtained by this method exhibit high efficiency. In addition, the flexible OLEDs keep good performance under a small bending radius.

Cui, Hai-Feng; Zhang, Yi-Fan; Li, Chuan-Nan

2014-07-01

82

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

83

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 (1217 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. PMID:22708072

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

2012-01-01

84

Graphene as an anti-permeation and protective layer for indium-free transparent electrodes.  

PubMed

We show that graphene can be used as a protective layer for transparent electrodes made of materials which would otherwise deteriorate when exposed to the environment. In particular, we investigate aluminum-doped zinc oxides and ultrathin copper films capped with a one-atom graphene layer in damp heat (95% relative humidity and 95 C) and high temperature (up to 180 C) conditions. The results clearly indicate that a graphene layer can strongly reduce degradation of the electrodes' electrical, optical properties and surface morphology, thus preserving the functionality of the transparent electrodes. The proposed technique is particularly suitable for flexible optoelectronic devices thanks to the mechanical strength of graphene when subjected to bending. PMID:22972183

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

2012-10-01

85

Indium Free Transparent Electrodes with a Tungsten Oxide Hole Blocking Layer for Organic Photovoltaic Devices  

NASA Astrophysics Data System (ADS)

Indium Tin Oxide (ITO), the standard transparent electrode used in organic photovoltaic (OPV) devices, is expensive and cannot be deposited well on flexible plastic substrates due to its high temperature post deposition annealing. As a replacement for ITO, we used a sputtered Al-ZnO/Ag/WOx film as the transparent electrode. The work function of this electrode was found using a Kelvin Probe to be between 5 and 5.4 eV, depending on thickness. We tested several OPV materials of varying LUMO and HOMO levels on the WOx layer and found that a difference of greater than 0.2 eV between the HOMO of the donor and the conduction band of the WOx resulted in poor device performance. We further investigated the alteration of the WOx work function through doping and altering the thickness. Device analysis and cross sectional transmission electron microscope (TEM) pictures using a focused ion beam were performed.

Murray, Roy; Reinecke, Patrick; Rujisamphan, Nopporn; Wrfel, Uli; Shah, S. Ismat

2013-03-01

86

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

87

High-performance plastic platinized counter electrode via photoplatinization technique for flexible dye-sensitized solar cells.  

PubMed

A photoplatinization technique was proposed to deposit Pt on a thin TiO(2) layer modified indium tin oxide-coated polyethylene naphthalate (ITO/PEN) substrate at low temperature (about 50 C after 1 h of UV irradiation) for the first time. The fabrication process includes coating and hydrolyzing the tetra-n-butyl titanate to form a TiO(2)-modified layer and the photoplatinization of the modified substrate in H(2)PtCl(6)/2-propanol precursor solution under UV irradiation. The obtained platinized electrodes were used as counter electrodes (CE) for flexible dye-sensitized solar cells (FDSCs). The well-optimized platinized electrode showed high optical transmittance, up to 76.5% between 400 and 800 nm (T(av)), and the charge transfer resistance (R(ct)) was as low as 0.66 ? cm(2). A series of characterizations also demonstrated the outstanding chemical/electrochemical durability and mechanical stability of the platinized electrode. The FDSCs with TiO(2)/Ti photoanodes and the obtained CEs achieved a power conversion efficiency (PCE) up to 8.12% under rear-side irradiation (AM 1.5 illumination, 100 mW cm(-2)). The obtained CEs were also employed in all-plastic bifacial DSCs. When irradiated from the rear side, the bifacial FDSC yielded a PCE of 6.26%, which approached 90% that of front-side irradiation (6.97%). Our study revealed that, apart from serving as a functional layer for deposition of Pt, the thin TiO(2) layer modification on ITO/PEN substrates also played an important role in improving the transparency and the mechanical properties of the CE. The effect of the thickness of the TiO(2) layer for Pt coating on the performance of the CE was also investigated. PMID:23039879

Fu, Nian-Qing; Fang, Yan-Yan; Duan, Yan-Dong; Zhou, Xiao-Wen; Xiao, Xu-Rui; Lin, Yuan

2012-11-27

88

Properties of an Au/Pt bilayered counter electrode in dye sensitized solar cells  

NASA Astrophysics Data System (ADS)

A 0.45 cm2 dye-sensitized solar cell (DSSC) device with glass/FTO/blocking layer/TiO2/dye/electrolyte/50 nm Pt/50 nm Au/glass was prepared to improve the energy conversion efficiency by applying an Au/Pt bilayer to the flat glass substrate of the counter electrode (CE). For comparison, Au and Pt CEs, 100 nm in thickness, on flat glass substrates were also prepared using the same method. The photovoltaic properties, such as the short circuit current density ( J sc ), open circuit voltage ( V oc ), fill factor ( FF) and energy conversion efficiency (ECE), were checked using a solar simulator and potentiostat. The strain of a Pt thin film was examined by x-ray diffraction. The sheet resistance and interface resistance were examined using a four point probe and impedance measurements. The measured energy conversion efficiencies of the dye-sensitized solar cell devices with Pt only and Au/Pt bilayer counter electrodes were 4.60% and 5.28%, respectively. The Au/Pt bilayer was confirmed by XRD, which also revealed a large compressive strain of -6.66 10-3 in the Pt layer. The interface resistance at the interface between the counter electrode and electrolyte decreased when an Au/Pt bilayered thin film was applied. The increase in efficiency at the Au/Pt bilayered counter electrode was attributed to the effect of a compressive strain field formed at the Pt layer and the low resistive Au layer used.

Noh, Yunyoung; Song, Ohsung

2014-09-01

89

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

90

Printable highly catalytic Pt- and TCO-free counter electrode for dye-sensitized solar cells.  

PubMed

Here we show that a counter electrode based on carbon network supported Cu2ZnSnS4 nanodots on Mo-coated soda-lime glass for dye-sensitized solar cells can outperform the conventional best electrode with Pt nanoparticles on the fluorine-doped SnO2 conducting glass. In the as-developed electrode, all of the elements are of high abundance ratios with low materials cost. The fabrication is scalable because it is conducted by a screen-printing based approach. Therefore, this research lays a solid ground for the large area fabrication of high-performance dye-sensitized solar cell at reduced material cost. PMID:24467193

He, Jian; Lee, Lawrence Tien Lin; Yang, Shihang; Li, Quan; Xiao, Xudong; Chen, Tao

2014-02-26

91

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

92

Nickel incorporated carbon nanotube/nanofiber composites as counter electrodes for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

A nickel incorporated carbon nanotube/nanofiber composite (Ni-CNT-CNF) was used as a low cost alternative to Pt as counter electrode (CE) for dye-sensitized solar cells (DSCs). Measurements based on energy dispersive X-rays spectroscopy (EDX) showed that the majority of the composite CE was carbon at 88.49 wt%, while the amount of Ni nanoparticles was about 11.51 wt%. Measurements based on electrochemical impedance spectroscopy (EIS) showed that the charge transfer resistance (Rct) of the Ni-CNT-CNF composite electrode was 0.71 ? cm2, much lower than that of the Pt electrode (1.81 ? cm2). Such a low value of Rct indicated that the Ni-CNT-CNF composite carried a higher catalytic activity than the traditional Pt CE. By mixing with CNTs and Ni nanoparticles, series resistance (Rs) of the Ni-CNT-CNF electrode was measured as 5.96 ? cm2, which was close to the Rs of 5.77 ? cm2 of the Pt electrode, despite the significant difference in their thicknesses: ~22 ?m for Ni-CNT-CNF composite, while ~40 nm for Pt film. This indicated that use of a thick layer (tens of microns) of Ni-CNT-CNF counter electrode does not add a significant amount of resistance to the total series resistance (Rs-tot) in DSCs. The DSCs based on the Ni-CNT-CNF composite CEs yielded an efficiency of 7.96% with a short circuit current density (Jsc) of 15.83 mA cm-2, open circuit voltage (Voc) of 0.80 V, and fill factor (FF) of 0.63, which was comparable to the device based on Pt, that exhibited an efficiency of 8.32% with Jsc of 15.01 mA cm-2, Voc of 0.83, and FF of 0.67.

Joshi, Prakash; Zhou, Zhengping; Poudel, Prashant; Thapa, Amit; Wu, Xiang-Fa; Qiao, Qiquan

2012-08-01

93

Hierarchical nanostructured spherical carbon with hollow core\\/mesoporous shell as a highly efficient counter electrode in CdSe quantum-dot-sensitized solar cells  

Microsoft Academic Search

Hierarchical nanostructured spherical carbon with hollow core\\/mesoporous shell (HCMS) was explored as a counter electrode in CdSe quantum-dot-sensitized solar cells. Compared with conventional Pt electrodes and commercially available activated carbon, the HCMS carbon counter electrode exhibits a much larger fill factor due to the considerably decreased charge transfer resistance at the interface of the counter electrode\\/polysulfide electrolyte. Furthermore, a solar

Sheng-Qiang Fan; Baizeng Fang; Jung Ho Kim; Jeum-Jong Kim; Jong-Sung Yu; Jaejung Ko

2010-01-01

94

Design of red, green, blue transparent electrodes for flexible optical devices.  

PubMed

Controlling the wavelength of electrodes within a desirable region is important in most optoelectronic devices for enhancing their efficiencies. Here, we investigated a full-color flexible transparent electrode using a wavelength matching layer (WML). The WMLs were able to adjust the optical-phase thickness of the entire electrode by controlling refractive indices and were capable of producing desirable colors in the visible band from 470 to 610 nm. Electrodes with tungsten oxide (WO3) having a refractive index of 1.9 showed high transmittance (T = 90.5%) at 460 nm and low sheet resistance (Rs = 11.08 ?/sq), comparable with those of indium tin oxide (ITO, T = 86.4%, Rs = 12 ?/sq). The optimum structure of electrodes determined by optical simulation based on the characteristic matrix method agrees well with that based on the experimental method. Replacing the ITO electrode with the WO3 electrode, the luminance of blue organic light-emitting diodes (? = 460 nm) at 222 mA/cm2 increased from 7020 to 7200 cd/m2. PMID:25322180

Kim, Sungjun; Cho, Hyung Won; Hong, Kihyon; Son, Jun Ho; Kim, Kisoo; Koo, Bonhyeong; Kim, Sungjoo; Lee, Jong-Lam

2014-08-25

95

Hierarchical nanostructured spherical carbon with hollow core/mesoporous shell as a highly efficient counter electrode in CdSe quantum-dot-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Hierarchical nanostructured spherical carbon with hollow core/mesoporous shell (HCMS) was explored as a counter electrode in CdSe quantum-dot-sensitized solar cells. Compared with conventional Pt electrodes and commercially available activated carbon, the HCMS carbon counter electrode exhibits a much larger fill factor due to the considerably decreased charge transfer resistance at the interface of the counter electrode/polysulfide electrolyte. Furthermore, a solar cell with the HCMS carbon counter electrode presents a high power conversion efficiency of up to 3.90% as well as an incident photon-to-current conversion efficiency peak of 80%.

Fan, Sheng-Qiang; Fang, Baizeng; Kim, Jung Ho; Kim, Jeum-Jong; Yu, Jong-Sung; Ko, Jaejung

2010-02-01

96

Two carboxyethyltin functionalized polyoxometalates for assembly on carbon nanotubes as efficient counter electrode materials in dye-sensitized solar cells.  

PubMed

Two novel open-chain carboxyethyltin decorated sandwich-type germanotungstates have been successfully synthesized. They could markedly increase the electrocatalytic activity of single-walled carbon nanotubes toward triiodide reduction when assembled into composite electrodes, which have shown a conversion efficiency of 6.32% that is comparable to that of Pt electrodes (6.29%) when used as counter electrodes in dye-sensitized solar cells. PMID:25317838

Sang, Xiao-Jing; Li, Jian-Sheng; Zhang, Lan-Cui; Zhu, Zai-Ming; Chen, Wei-Lin; Li, Yang-Guang; Su, Zhong-Min; Wang, En-Bo

2014-10-28

97

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

98

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

99

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

100

Efficient iron sulfide counter electrode for quantum dots-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Iron sulfide is explored as the counter electrode (CE) in quantum dots-sensitized solar cells (QDSCs), which is prepared by simply immersing carbon steel in Na2S solution. The photoelectrochemical performance and the electrocatalytic property of iron sulfide are much higher than those of Pt and are very close to those of Cu2S. Since the preparation method of iron sulfide CE is simple, carbon steel substrate is stable in polysulfide electrolyte, the storage of Fe element in earth is very abundant and iron ions are environmentally friendly, iron sulfide shows much prospect as the efficient, stable, lost-cost and environmentally friendly CE of QDSCs.

Chen, Haining; Zhu, Liqun; Liu, Huicong; Li, Weiping

2014-01-01

101

Graphene-silver nanowire hybrid structure as a transparent and current spreading electrode in ultraviolet light emitting diodes  

NASA Astrophysics Data System (ADS)

We report a device that combines graphene film and Ag nanowires (AgNWs) as transparent and current spreading electrodes for ultra-violet (UV) light emitting diode (LED) with interesting characteristics for the potential use in the deep UV region. The current-voltage characteristics and electroluminescence (EL) performance show that graphene network on AgNWs well-operates as a transparent and current spreading electrode in UV LED devices. In addition, scanning electron microscopy and EL images exhibit that graphene film act as the protection layer of AgNWs layer as well as a transparent conducting network, by bridging AgNWs.

Hoon Seo, Tae; Kyoung Kim, Bo; Shin, GangU; Lee, Changhyup; Jong Kim, Myung; Kim, Hyunsoo; Suh, Eun-Kyung

2013-07-01

102

Stretchable and Transparent Electrodes using Hybrid Structures of Graphene-Metal Nanotrough Networks with High Performances and Ultimate Uniformity.  

PubMed

Transparent electrodes that can maintain their electrical and optical properties stably against large mechanical deformations are essential in numerous applications of flexible and wearable electronics. In this paper, we report a comprehensive analysis of the electrical, optical, and mechanical properties of hybrid nanostructures based on graphene and metal nanotrough networks as stretchable and transparent electrodes. Compared to the single material of graphene or the nanotrough, the formation of this hybrid can improve the uniformity of sheet resistance significantly, that is, a very low sheet resistance (1 ?/sq) with a standard deviation of less than 0.1 ?/sq, high transparency (91% in the visible light regime), and superb stretchability (80% in tensile strain). The successful demonstration of skin-attachable, flexible, and transparent arrays of oxide semiconductor transistors fabricated using hybrid electrodes suggests substantial promise for the next generation of electronic devices. PMID:25299634

An, Byeong Wan; Hyun, Byung Gwan; Kim, So-Yun; Kim, Minji; Lee, Mi-Sun; Lee, Kyongsoo; Koo, Jae Bon; Chu, Hye Yong; Bae, Byeong-Soo; Park, Jang-Ung

2014-11-12

103

High-durable AgNi nanomesh film for a transparent conducting electrode.  

PubMed

Uniform metal nanomesh structures are promising candidates that may replace of indium-tin oxide (ITO) in transparent conducting electrodes (TCEs). However, the durability of the uniform metal mesh has not yet been studied. For this reason, a comparative analysis of the durability of TCEs based on pure Ag and AgNi nanomesh, which are fabricated by using simple transfer printing, is performed. The AgNi nanomesh shows high long-term stability to oxidation, heat, and chemicals compared with that of pure Ag nanomesh. This is because of nickel in the AgNi nanomesh. Furthermore, the AgNi nanomesh shows strong adhesion to a transparent substrate and good stability after repeated bending. PMID:24840606

Kim, Han-Jung; Lee, Su-Han; Lee, Jihye; Lee, Eung-Sug; Choi, Jun-Hyuk; Jung, Jun-Ho; Jung, Joo-Yun; Choi, Dae-Geun

2014-09-24

104

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

105

Nickel incorporated carbon nanotube/nanofiber composites as counter electrodes for dye-sensitized solar cells.  

PubMed

A nickel incorporated carbon nanotube/nanofiber composite (Ni-CNT-CNF) was used as a low cost alternative to Pt as counter electrode (CE) for dye-sensitized solar cells (DSCs). Measurements based on energy dispersive X-rays spectroscopy (EDX) showed that the majority of the composite CE was carbon at 88.49 wt%, while the amount of Ni nanoparticles was about 11.51 wt%. Measurements based on electrochemical impedance spectroscopy (EIS) showed that the charge transfer resistance (R(ct)) of the Ni-CNT-CNF composite electrode was 0.71 ? cm(2), much lower than that of the Pt electrode (1.81 ? cm(2)). Such a low value of R(ct) indicated that the Ni-CNT-CNF composite carried a higher catalytic activity than the traditional Pt CE. By mixing with CNTs and Ni nanoparticles, series resistance (R(s)) of the Ni-CNT-CNF electrode was measured as 5.96 ? cm(2), which was close to the R(s) of 5.77 ? cm(2) of the Pt electrode, despite the significant difference in their thicknesses: ?22 ?m for Ni-CNT-CNF composite, while ?40 nm for Pt film. This indicated that use of a thick layer (tens of microns) of Ni-CNT-CNF counter electrode does not add a significant amount of resistance to the total series resistance (R(s-tot)) in DSCs. The DSCs based on the Ni-CNT-CNF composite CEs yielded an efficiency of 7.96% with a short circuit current density (J(sc)) of 15.83 mA cm(-2), open circuit voltage (V(oc)) of 0.80 V, and fill factor (FF) of 0.63, which was comparable to the device based on Pt, that exhibited an efficiency of 8.32% with J(sc) of 15.01 mA cm(-2), V(oc) of 0.83, and FF of 0.67. PMID:22868278

Joshi, Prakash; Zhou, Zhengping; Poudel, Prashant; Thapa, Amit; Wu, Xiang-Fa; Qiao, Qiquan

2012-09-21

106

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

107

Transferable self-welding silver nanowire network as high performance transparent flexible electrode  

NASA Astrophysics Data System (ADS)

High performance transparent electrodes (TEs) with figures-of-merit as high as 471 were assembled using ultralong silver nanowires (Ag NWs). A room-temperature plasma was employed to enhance the conductivity of the Ag NW TEs by simultaneously removing the insulating PVP layer coating on the NWs and welding the junctions tightly. Furthermore, we developed a general way to fabricate TEs regardless of substrate limitations by transferring the as-fabricated Ag NW network onto various substrates directly, and the transmittance can remain as high as 91% with a sheet resistivity of 13 ?/sq. The highly robust and stable flexible TEs will have broad applications in flexible optoelectronic and electronic devices.

Zhu, Siwei; Gao, Yuan; Hu, Bin; Li, Jia; Su, Jun; Fan, Zhiyong; Zhou, Jun

2013-08-01

108

Highly flexible, hybrid-structured indium tin oxides for transparent electrodes on polymer substrates  

SciTech Connect

We developed highly flexible, hybrid-structured crystalline indium tin oxide (ITO) for use as transparent electrodes on polymer substrates by embedding Ag nanoparticles (AgNPs) into the substrate. The hybrid ITO consists of domains in one orientation grown on the AgNPs and a matrix of the other orientation. The domains are stronger than the matrix and function as barriers to crack propagation. As a result, both the critical bending radius (r{sub c}) (under which the resistivity change ({Delta}{rho}) is less than a given value) and the change in {Delta}{rho} with decreasing r significantly decreased in the hybrid ITO compared with homogenous ITO.

Triambulo, Ross E.; Kim, Jung-Hoon; Park, Jin-Woo [Department of Materials Science and Engineering, Yonsei University, Seoul (Korea, Republic of)] [Department of Materials Science and Engineering, Yonsei University, Seoul (Korea, Republic of); Na, Min-Young; Chang, Hye-Jung [Advanced Analysis Center, Korea Institute of Science and Technology (KIST), Seoul (Korea, Republic of)] [Advanced Analysis Center, Korea Institute of Science and Technology (KIST), Seoul (Korea, Republic of)

2013-06-17

109

Highly flexible, hybrid-structured indium tin oxides for transparent electrodes on polymer substrates  

NASA Astrophysics Data System (ADS)

We developed highly flexible, hybrid-structured crystalline indium tin oxide (ITO) for use as transparent electrodes on polymer substrates by embedding Ag nanoparticles (AgNPs) into the substrate. The hybrid ITO consists of domains in one orientation grown on the AgNPs and a matrix of the other orientation. The domains are stronger than the matrix and function as barriers to crack propagation. As a result, both the critical bending radius (rc) (under which the resistivity change (??) is less than a given value) and the change in ?? with decreasing r significantly decreased in the hybrid ITO compared with homogenous ITO.

Triambulo, Ross E.; Kim, Jung-Hoon; Na, Min-Young; Chang, Hye-Jung; Park, Jin-Woo

2013-06-01

110

Modelling of optical transport behavior of organic photovoltaic devices with nano-pillar transparent conducting electrodes  

NASA Astrophysics Data System (ADS)

Optical transport behavior of organic photo-voltaic devices with nano-pillar transparent electrodes is investigated in this paper in order to understand possible enhancement of their charge-collection efficiency. Modeling and simulations of optical transport due to this architecture show an interesting regime of length-scale dependent optical characteristics. An electromagnetic wave propagation model is employed with simulation objectives toward understanding the mechanism of optical scattering and waveguide effects due to the nano-pillars and effective transmission through the active layer. Partial filling of gaps between the nano-pillars due to the nano-fabrication process is taken into consideration. Observations made in this paper will facilitate appropriate design rules for nano-pillar electrodes.

Jagdish, A. K.; Ramamurthy, Praveen C.; Mahapatra, D. Roy; Hegde, Gopalkrishna

2014-08-01

111

Large-scale graphene-based composite films for flexible transparent electrodes fabricated by electrospray deposition  

NASA Astrophysics Data System (ADS)

Large-scale transparent conducting electrodes were fabricated using the electrospray method on a glass wafer and polyethylene terephthalate film using chemically reduced graphene oxide and poly (3,4-ethylenedioxythiophene) (PEDOT). Graphene oxide (GO) is prepared by the modified Hummers method, and reduced GO (RG) is prepared at low temperature. By varying the concentration of RG and PEDOT of the composite material on the substrate, the electrical conductivity and transmittance of the electrode was controlled. The optical transmittance values of the graphene-based electrode at a wavelength of 550 nm were between 81 and 95% and had sheet resistances from 370 to 5400 ? sq?1. After 1000 cycles of a bending test, the sheet resistances of the graphene-based composite films were unchanged. Different types of graphene and graphene-based electrodes were characterized by field-emission scanning electron microscopy, high-resolution transmission electron microscopy, high-resolution Raman spectroscopy, x-ray photoelectron spectroscopy, x-ray diffraction, transmittance, and electrical conductivity measurements.

Kim, Woo Sik; Moon, Sook Young; Kim, Hui Jin; Park, Sungjin; Koyanagi, Jun; Huh, Hoon

2014-12-01

112

On-chip amperometric measurement of quantal catecholamine release using transparent indium tin oxide electrodes.  

PubMed

Carbon-fiber amperometry has been extensively used to monitor the time course of catecholamine release from cells as individual secretory granules discharge their contents during the process of quantal exocytosis, but microfabricated devices offer the promise of higher throughput. Here we report development of a microchip device that uses transparent indium tin oxide (ITO) electrodes to measure quantal exocytosis from cells in microfluidic channels. ITO films on a glass substrate were patterned as 20-mum-wide stripes using photolithography and wet etching and then coated with polylysine to facilitate cell adherence. Microfluidic channels (100 mum wide by 100 mum deep) were formed by molding poly(dimethylsiloxane) (PDMS) on photoresist and then reversibly sealing the PDMS slab to the ITO-glass substrate. Bovine adrenal chromaffin cells were loaded into the microfluidic channel and adhered to the ITO electrodes. Cells were stimulated to secrete by perfusing a depolarizing "high-K" solution while monitoring oxidation of catecholamines on the ITO electrode beneath the cell using amperometry. Amperometric spikes with charges ranging from 0.1 to 1.5 pC were recorded with a signal-to-noise ratio comparable to that of carbon-fiber electrodes. Further development of this approach will enable high-throughput measurement of quantal catecholamine release simultaneously with optical cell measurements such as fluorescence. PMID:16615759

Sun, Xiuhua; Gillis, Kevin D

2006-04-15

113

Solid-state dye-sensitized solar cells using polymerized ionic liquid electrolyte with platinum-free counter electrode.  

PubMed

A polymerized ionic liquid electrolyte and platinum-free counter electrode are employed for solid-state DSSCs. We are able to prepare a thin polymer electrolyte layer on nanocrystalline TiO(2) in order to reduce the cell resistance. In addition, an electron conductive polymer (PEDOT/PSS) or a single-wall carbon nanotube gel is used with the cell as an inexpensive counter electrode instead of platinum. The overall photon-to-current conversion efficiency was 3.7% in this study. PMID:20145859

Kawano, Ryuji; Katakabe, Toru; Shimosawa, Hironobu; Nazeeruddin, Md Khaja; Grtzel, Michael; Matsui, Hiroshi; Kitamura, Takayuki; Tanabe, Nobuo; Watanabe, Masayoshi

2010-02-28

114

Functionalized graphene sheets in dye-sensitized solar cell counter electrodes  

NASA Astrophysics Data System (ADS)

The use of thermally exfoliated graphite oxide, commonly referred to as functionalized graphene sheets (FGSs), was investigated as a catalytic counter electrode material in dye-sensitized solar cells to substitute for platinum nanoparticles traditionally used in devices. A catalyst's activity depends both on the material's intrinsic activity as well as on its surface area accessible for reaction. Thus, this work aimed i) to determine the intrinsic activity of FGSs with various chemical compositions and structures, and ii) to create high surface area networks of FGSs to use as catalytic electrodes in dye-sensitized solar cells. Monolayers of FGSs were fabricated and electrochemically tested to determine the intrinsic catalytic activity for a common dye-sensitized solar cell redox mediator, cobalt bipyridine. It was found that lattice defect rich, oxygen-site poor FGSs catalyze the reduction of the cobalt complex as well as platinum does, exhibiting a rate constant of ~ 6 x 10-3 cm/s. This rate is an order of magnitude faster than exhibited with oxygen-site rich graphene oxide, and over two orders of magnitude faster than found with the basal plane of graphite (as a surrogate for pristine graphene). FGSs are less catalytic towards the iodide/triiodide redox mediator, thus larger surface areas must be used for effective catalysis. In this work, conductive, high surface area networks of FGSs were produced by first tape casting surfactant-stabilized aqueous suspensions of FGSs and then thermolyzing the surfactant materials. Iodide/triiodide mediated dye-sensitized solar cells using these FGS electrodes exhibited power conversion efficiencies within 10% of devices using platinum nanoparticles. Furthermore, to interpret the catalytic activity of FGSs towards the reduction of triiodide, a new electrochemical impedance spectroscopy equivalent circuit was proposed that matches the observed spectra features to the appropriate phenomena. Lastly, improved catalytic performance was achieved through better control of electrode morphology. By using ethyl cellulose as a sacrificial binder, and partially thermolyzing it, electrodes were created which exhibited lower effective charge transfer resistance (< 1 ?cm 2) than the traditional platinum electrodes for the iodide/triiodide, the cobalt bipyridine, and a sulfur-based redox couple. Dye-sensitized solar cells using these FGS electrodes had power conversion efficiencies equal to or greater than those using platinum nanoparticles with each of the three major redox mediators.

Roy-Mayhew, Joseph Dominic

115

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

116

Low temperature preparation of a high performance Pt\\/SWCNT counter electrode for flexible dye-sensitized solar cells  

Microsoft Academic Search

A platinum\\/single-wall carbon nanotube (Pt\\/SWCNT) film was sprayed onto a flexible indium-doped tin oxide coated polyethylene naphthalate (ITO\\/PEN) substrate to form a counter electrode for use in a flexible dye-sensitized solar cell using a vacuum thermal decomposition method at low temperature (120C). The obtained Pt\\/SWCNT electrode showed good chemical stability and light transmittance and had lower charge transfer resistance and

Yaoming Xiao; Jihuai Wu; Gentian Yue; Jianmin Lin; Miaoliang Huang; Zhang Lan

2011-01-01

117

Counter electrodes from binary ruthenium selenide alloys for 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, cost-effectiveness, relatively high efficiency, and easy fabrication. However, the reduction of fabrication cost without sacrifice of power conversion efficiencies of the DSSCs is a golden rule for their commercialization. Here we design a new binary ruthenium selenide (Ru-Se) alloy counter electrodes (CEs) by a low-temperature hydrothermal reduction method. The electrochemical behaviors are evaluated by cyclic voltammogram, electrochemical impedance, and Tafel measurements, giving an optimized Ru/Se molar ratio of 1:1. The DSSC device with RuSe alloy CE achieves a power conversion efficiency of 7.15%, which is higher than 5.79% from Pt-only CE based DSSC. The new concept, easy process along with promising results provide a new approach for reducing cost but enhancing photovoltaic performances of DSSCs.

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

2014-12-01

118

A flexible polypyrrole-coated fabric counter electrode for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

The current dye-sensitized solar cell (DSSC) technology is mostly based on fluorine doped tin oxide (FTO) coated glass substrate. The main problem with the FTO glass substrate is its rigidity, heavyweight and high cost. DSSCs with a fabric as substrate not only offer the advantages of flexibility, stretchability and light mass, but also provide the opportunities for easy implantation to wearable electronics. Herein, a novel fabric counter electrode (CE) for DSSCs has been reported employing a daily-used cotton fabric as substrate and polypyrrole (PPy) as catalytic material. Nickel (Ni) is deposited on the cotton fabric as metal contact by a simple electroless plating method to replace the expensive FTO. PPy is synthesized by in situ polymerization of pyrrole monomer on the Ni-coated fabric. The fabric CE shows sufficient catalytic activity towards the reduction of I3-. The DSSC fabricated using the fabric CE exhibits power conversion efficiency of ?3.30% under AM 1.5.

Xu, Jie; Li, Meixia; Wu, Lei; Sun, Yongyuan; Zhu, Ligen; Gu, Shaojin; Liu, Li; Bai, Zikui; Fang, Dong; Xu, Weilin

2014-07-01

119

Correlation between microstructure and property of electroless deposited Pt counter electrodes on plastic substrate for dye-sensitized solar cells  

Microsoft Academic Search

Flexible Pt counter electrodes (CEs) were prepared on indium-doped tin oxide coated polyethylene naphthalate (ITO-PEN) substrate by electroless deposition. The correlation between the microstructure and the property of the Pt CEs was investigated. Results showed that isolated Pt nanoparticles were uniformly distributed on the ITO surface at a short deposition duration, and then grew with the deposition duration, leading to

Xue-Long He; Mei Liu; Guan-Jun Yang; Sheng-Qiang Fan; Chang-Jiu Li

120

Impedance analysis of nanocarbon DSSC electrodes  

NASA Astrophysics Data System (ADS)

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 low charge transfer resistance promising an improved fill factor (and efficiency) in DSSCs assembled with such materials as counter electrodes.

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

2009-07-01

121

Pt-free counter electrode for dye-sensitized solar cells with high efficiency.  

PubMed

Dye-sensitized solar cells (DSSCs) have attracted widespread attention in recent years as potential cost-effective alternatives to silicon-based and thin-film solar cells. Within typical DSSCs, the counter electrode (CE) is vital to collect electrons from the external circuit and catalyze the I3 (-) reduction in the electrolyte. Careful design of the CEs can improve the catalytic activity and chemical stability associated with the liquid redox electrolyte used in most cells. In this Progress Report, advances made by our groups in the development of CEs for DSSCs are reviewed, highlighting important contributions that promise low-cost, efficient, and robust DSSC systems. Specifically, we focus on the design of novel Pt-free CE catalytic materials, including design ideas, fabrication approaches, characterization techniques, first-principle density functional theory (DFT) calculations, ab-initio Car-Parrinello molecular dynamics (CPMD) simulations, and stability evaluations, that serve as practical alternatives to conventional noble metal Pt electrodes. We stress the merits and demerits of well-designed Pt-free CEs, such as carbon materials, conductive polymers, transition metal compounds (TMCs) and their corresponding hybrids. Also, the prospects and challenges of alternative Pt catalysts for their applications in new-type DSSCs and other catalytic fields are discussed. PMID:25080873

Yun, Sining; Hagfeldt, Anders; Ma, Tingli

2014-09-01

122

Transparency  

ERIC Educational Resources Information Center

Citizens now expect access to information, particularly from public institutions like local school districts. They demand input and accountability. Cultural and technological changes, such as the Internet, make it possible for districts to comply. Yet transparency--the easily seen and understood actions of a school district and the thinking behind

LaFee, Scott

2009-01-01

123

Counter-ion Dependent, Longitudinal Unzipping of Multi-Walled Carbon Nanotubes to Highly Conductive and Transparent Graphene Nanoribbons  

PubMed Central

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+, SO42? 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

124

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

125

Counter-ion Dependent, Longitudinal Unzipping of Multi-Walled Carbon Nanotubes to Highly Conductive and Transparent Graphene Nanoribbons  

NASA Astrophysics Data System (ADS)

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+, SO42- 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.

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

2014-03-01

126

Transparent TiO2 nanotube electrodes via thin layer anodization: fabrication and use in electrochromic devices.  

PubMed

In the present work, we describe an anodization process that is able to fully transform a thin Ti metal layer on a conductive glass into a TiO(2) nanotubular array. Under optimized conditions, nanotube electrodes can be obtained that are completely transparent and defect-free and allow electrochromic switching. These electrochromic electrodes show remarkable properties and can be directly integrated into devices. PMID:19397345

Berger, S; Ghicov, A; Nah, Y-C; Schmuki, P

2009-05-01

127

Reference and counter electrode positions affect electrochemical characterization of bioanodes in different bioelectrochemical systems.  

PubMed

The placement of the reference electrode (RE) in various bioelectrochemical systems is often varied to accommodate different reactor configurations. While the effect of the RE placement is well understood from a strictly electrochemistry perspective, there are impacts on exoelectrogenic biofilms in engineered systems that have not been adequately addressed. Varying distances between the working electrode (WE) and the RE, or the RE and the counter electrode (CE) in microbial fuel cells (MFCs) can alter bioanode characteristics. With well-spaced anode and cathode distances in an MFC, increasing the distance between the RE and anode (WE) altered bioanode cyclic voltammograms (CVs) due to the uncompensated ohmic drop. Electrochemical impedance spectra (EIS) also changed with RE distances, resulting in a calculated increase in anode resistance that varied between 17 and 31?? (-0.2?V). While WE potentials could be corrected with ohmic drop compensation during the CV tests, they could not be automatically corrected by the potentiostat in the EIS tests. The electrochemical characteristics of bioanodes were altered by their acclimation to different anode potentials that resulted from varying the distance between the RE and the CE (cathode). These differences were true changes in biofilm characteristics because the CVs were electrochemically independent of conditions resulting from changing CE to RE distances. Placing the RE outside of the current path enabled accurate bioanode characterization using CVs and EIS due to negligible ohmic resistances (0.4??). It is therefore concluded for bioelectrochemical systems that when possible, the RE should be placed outside the current path and near the WE, as this will result in more accurate representation of bioanode characteristics. Biotechnol. Bioeng. 2014;111: 1931-1939. 2014 Wiley Periodicals, Inc. PMID:24729040

Zhang, Fang; Liu, Jia; Ivanov, Ivan; Hatzell, Marta C; Yang, Wulin; Ahn, Yongtae; Logan, Bruce E

2014-10-01

128

Monolithic quasi-solid-state dye-sensitized solar cells based on graphene-modified mesoscopic carbon-counter electrodes  

NASA Astrophysics Data System (ADS)

A monolithic quasi-solid-state dye-sensitized solar cell (DSSC) based on graphene-modified mesoscopic carbon-counter electrode is developed. A TiO2-working electrode layer, ZrO2 spacer layer, and carbon counter electrode layer were constructed on a single conducting glass substrate by screen printing. The quasi-solid-state polymer gel electrolyte employed a polymer composite as the gelator, and effectively infiltrated the porous layers. Fabricated with normal carbon-counter electrode (NC-CE) containing graphite and carbon black, the DSSC had a power conversion efficiency (PCE) of 5.09% with the fill factor of 0.63 at 100 mW cm-2 AM1.5 illumination. When the NC-CE was modified with graphene sheets, the PCE and fill factor were enhanced to 6.27% and 0.71, respectively. This improvement indicates excellent conductivity and high electrocatalytic activity of the graphene sheets, which have been considered as a promising platinum-free electrode material for DSSCs.

Rong, Yaoguang; Han, Hongwei

2013-01-01

129

Monolithic quasi-solid-state dye-sensitized solar cells based on graphene modified mesoscopic carbon counter electrodes  

NASA Astrophysics Data System (ADS)

We have developed a monolithic quasi-solid-state dye-sensitized solar cell (DSSC) based on graphene modified mesoscopic carbon counter electrode (GC-CE), which offers a promising prospect for commercial applications. Based on the design of a triple layer structure, the TiO2 working electrode layer, ZrO2 spacer layer and carbon counter electrode (CE) layer are constructed on a single conducting glass substrate by screen-printing. The quasi-solid-state polymer gel electrolyte employs a polymer composite as the gelator and could effectively infiltrate into the porous layers. Fabricated with normal carbon counter electrode (NC-CE) containing graphite and carbon black, the device shows a power conversion efficiency (PCE) of 5.09% with the fill factor (FF) of 0.63 at 100 mW cm-2 AM1.5 illumination. When the NC-CE is modified with graphene sheets, the PCE and FF could be enhanced to 6.27% and 0.71, respectively. This improvement indicates excellent conductivity and high electrocatalytic activity of the graphene sheets, which have been considered as a promising platinum-free electrode material for DSSCs.

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

2013-03-01

130

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. PMID:23672498

2013-01-01

131

A dye-sensitized solar cell based on platinum nanotube counter electrode with efficiency of 9.05%  

NASA Astrophysics Data System (ADS)

Platinum nanotubes (PNTs) are directly grown on fluorine-doped tin oxide substrates by a facile polycarbonate template method. Morphology observation and electrochemical measurements indicate that the PNTs show a one-dimensional structure, lower charge-transfer resistance, larger exchange current density and higher electrocatalytic activity for iodide/triiodide redox reaction. Using the PNT as counter electrode and MgO as block layer on TiO2 film, the fabricated dye-sensitized solar cell achieves a light-to-electric energy conversion efficiency of 9.05% under a simulated solar light irradiation of 100mWcm-2, the efficiency is increased by 25.5% compared to that of DSSC based on conventional Pt counter electrode. Higher efficiency for the PNT electrode is due its one-dimensional nanostructure, large surface area and good electrochemical activity to iodide/triiodide couple.

Wu, Jihuai; Tang, Ziying; Huang, Yunfang; Huang, Miaoliang; Yu, Haijun; Lin, Jianming

2014-07-01

132

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

NASA Astrophysics Data System (ADS)

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.

Lim, Jeongmin; Ryu, Sang Yeoul; Kim, Jeonghun; Jun, Yongseok

2013-05-01

133

Ag@Ni core-shell nanowire network for robust transparent electrodes against oxidation and sulfurization.  

PubMed

Silver nanowire (Ag NW) based transparent electrodes are inherently unstable to moist and chemically reactive environment. A remarkable stability improvement of the Ag NW network film against oxidizing and sulfurizing environment by local electrodeposition of Ni along Ag NWs is reported. The optical transmittance and electrical resistance of the Ni deposited Ag NW network film can be easily controlled by adjusting the morphology and thickness of the Ni shell layer. The electrical conductivity of the Ag NW network film is increased by the Ni coating via welding between Ag NWs as well as additional conductive area for the electron transport by electrodeposited Ni layer. Moreover, the chemical resistance of Ag NWs against oxidation and sulfurization can be dramatically enhanced by the Ni shell layer electrodeposited along the Ag NWs, which provides the physical barrier against chemical reaction and diffusion as well as the cathodic protection from galvanic corrosion. PMID:24961495

Eom, Hyeonjin; Lee, Jaemin; Pichitpajongkit, Aekachan; Amjadi, Morteza; Jeong, Jun-Ho; Lee, Eungsug; Lee, Jung-Yong; Park, Inkyu

2014-10-01

134

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

135

Flexible transparent conducting hybrid film using a surface-embedded copper nanowire network: a highly oxidation-resistant copper nanowire electrode for flexible optoelectronics.  

PubMed

We report a flexible high-performance conducting film using an embedded copper nanowire transparent conducting electrode; this material can be used as a transparent electrode platform for typical flexible optoelectronic devices. The monolithic composite structure of our transparent conducting film enables simultaneously an outstanding oxidation stability of the copper nanowire network (14 d at 80 C), an exceptionally smooth surface topography (Rrms < 2 nm), and an excellent opto-electrical performances (Rsh = 25 ? sq(-1) and T = 82%). A flexible organic light emitting diode device is fabricated on the transparent conducting film to demonstrate its potential as a flexible copper nanowire electrode platform. PMID:25211125

Im, Hyeon-Gyun; Jung, Soo-Ho; Jin, Jungho; Lee, Dasom; Lee, Jaemin; Lee, Daewon; Lee, Jung-Yong; Kim, Il-Doo; Bae, Byeong-Soo

2014-10-28

136

Effective indium-doped zinc oxide buffer layer on silver nanowires for electrically highly stable, flexible, transparent, and conductive composite electrodes.  

PubMed

We demonstrate a flexible, transparent, and conductive composite electrode comprising silver nanowires (Ag NWs), and indium-doped zinc oxide (IZO) layers. IZO is sputtered onto an Ag NW layer, with the unique structural features of the resulting composite suitable as a flexible, transparent, conductive electrode. The IZO buffer layer prohibits surface oxidation of the Ag NW, and is thereby effective in preventing undesirable changes in electrical properties. The newly designed composite electrode is a promising alternative to conventional ITO films for the production of flexible and transparent electrodes to be applied in next-generation flexible electronic devices. PMID:24088674

Lee, Hyun Jun; Hwang, Ju Hyun; Choi, Kyung Bok; Jung, Sun-Gyu; Kim, Kyu Nyun; Shim, Yong Sub; Park, Cheol Hwee; Park, Young Wook; Ju, Byeong-Kwon

2013-11-13

137

Fabrication of a flexible Ag-grid transparent electrode using ac based electrohydrodynamic Jet printing  

NASA Astrophysics Data System (ADS)

In the dc voltage-applied electrohydrodynamic (EHD) jet printing of metal nanoparticles, the residual charge of droplets deposited on a substrate changes the electrostatic field distribution and interrupts the subsequent printing behaviour, especially for insulating substrates that have slow charge decay rates. In this paper, a sinusoidal ac voltage was used in the EHD jet printing process to switch the charge polarity of droplets containing Ag nanoparticles, thereby neutralizing the charge on a polyethylene terephthalate (PET) substrate. Printed Ag lines with a width of 10 m were invisible to the naked eye. After sintering lines with 500 m of line pitch at 180 C, a grid-type transparent electrode (TE) with a sheet resistance of 7 ? sq-1 and a dc to optical conductivity ratio of 300 at 84.2% optical transmittance was obtained, values that were superior to previously reported results. In order to evaluate the durability of the TE under bending stresses, the sheet resistance was measured as the number of bending cycles was increased. The sheet resistance of the Ag grid electrode increased only slightly, by less than 20% from its original value, even after 500 cycles. To the best of our knowledge, this is the first time that Ag (invisible) grid TEs have been fabricated on PET substrates by ac voltage applied EHD jet printing.

Park, Jaehong; Hwang, Jungho

2014-10-01

138

Silver nanowire composite thin films as transparent electrodes for Cu(In,Ga)Se?/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)Se? (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

139

CuInS? nanocrystals/PEDOT:PSS composite counter electrode for dye-sensitized solar cells.  

PubMed

An inorganic/organic nanocomposite comprised of CuInS(2) nanocrystals and poly(styrenesulfonate)-doped poly(3,4-ethylenedioxythiophene) (CIS/PEDOT:PSS) was explored as a promising candidate for the counter electrode (CE) in dye-sensitized solar cells (DSCs). Cyclic voltammetry measurements confirmed that this composite electrode exhibited better catalytic activity compared with pristine CuInS? or PEDOT:PSS electrode. Electrochemical impedance spectroscopy revealed that the composite film constitutes a three-dimensional catalytic network. The DSC using this composite CE can yield 6.50% photoelectric conversion efficiency, which is comparable to that of the conventional platinum CE (6.51%) and better than that of the pristine CuInS? (5.45%) or PEDOT:PSS (3.22%) electrode. PMID:23075280

Zhang, Zhongyi; Zhang, Xiaoying; Xu, Hongxia; Liu, Zhihong; Pang, Shuping; Zhou, Xinhong; Dong, Shanmu; Chen, Xiao; Cui, Guanglei

2012-11-01

140

Two-dimensional acoustic particle focusing enables sheathless chip Coulter counter with planar electrode configuration.  

PubMed

The field of cytometry has grown in scope and importance ever since the early 20th century with leaps in technology introducing the Coulter counter and the flow cytometer. Cytometry methods have brought about a revolution for the medical and biotechnology industry by providing fast and accurate analysis of cell and particle suspensions. Recent developments in the field aim at improving current cytometers and to provide miniaturized low-cost cytometry systems for point-of-care clinical diagnostics or research. In an attempt to address the need for particle positioning which is important for both impedance and optically based cytometers we present a microfluidic system which precisely positions cells and particles, using acoustic forces and subsequently performs measurements using an integrated and simple planar electrode Coulter-type impedance cytometer without the need for sheath flows. Data is presented to show how the acoustic method improves the accuracy of the impedance cytometer when prefocusing is employed to particles and cells (diluted whole blood). Confocal imaging and simulations support the findings and provide the basis for further improvements. The acoustophoretic prefocusing technique opens a path towards small, low cost cytometers while also providing an easy way to improve current systems. PMID:25300357

Grenvall, Carl; Antfolk, Christian; Bisgaard, Christer Zoffmann; Laurell, Thomas

2014-12-21

141

Surfactant-free synthesis of graphene-functionalized carbon nanotube film as a catalytic counter electrode in dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

We use graphene oxide (GO) as a surfactant to obtain stable colloidal dispersion of carbon nanotubes (CNTs). CNT films are subsequently synthesized successfully without the addition of any traditional surfactants. Dye-sensitized solar cells assembled using the resulting CNT film as a counter electrode deliver a power conversion efficiency up to 5.29%. More importantly, the additional reduced graphene oxide significantly increases the electrical conductivity and the catalytic activity of the CNT film. The cell performance using a CNT film counter electrode (5.29%) reaches 68.70% of that of cells prepared using a platinum film counter electrode (7.70%).

Ma, Jie; Zhou, Lu; Li, Cheng; Yang, Jinhu; Meng, Tao; Zhou, Huiming; Yang, Mingxuan; Yu, Fei; Chen, Junhong

2014-02-01

142

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

143

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

144

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

PubMed Central

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

2013-01-01

145

Conducting polymer-based counter electrode for a quantum-dot-sensitized solar cell (QDSSC) with a polysulfide electrolyte  

Microsoft Academic Search

Conducting polymer materials, i.e., polythiophene (PT), polypyrrole (PPy), and poly(3,4-ethylenedioxythiophene) (PEDOT) were used to prepare counter electrodes (CEs) for quantum-dot-sensitized solar cells (QDSSCs). The QDSSC with PEDOT-CE exhibited the highest solar-to-electricity conversion efficiency (?) of 1.35%, which is remarkably higher than those of the cells with PT-CE (0.09%) and PPy-CE (0.41%) and very slightly higher than that of the cell

Min-Hsin Yeh; Chuan-Pei Lee; Chen-Yu Chou; Lu-Yin Lin; Hung-Yu Wei; Chih-Wei Chu; R. Vittal; Kuo-Chuan Ho

146

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

147

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

SciTech Connect

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 (R{sub s} = 10 ohms/square ({Omega}#2;/?)) for electrical conduction. However, ITO is costly due to limited indium reserves, and it is brittle. These disadvantages have motivated the search for other conducting electrodes with similar or better properties. There has been research on a variety of electrode structures involving carbon nanotube networks, graphene films, nanowire and nanopatterned meshes and grids. Due to their novel characteristics in light manipulation and collection, photonic crystal structures show promise for further improvement. Here, we report on a new architecture consisting of nanoscale high aspect ratio metallic photonic structures as transparent electrodes fabricated via a combination of processes. For (Au) and silver (Ag) structures, the visible light transmission can reach as high as 80%, and the sheet resistance of the structure can be as low as 3.2{Omega}#2;/?. The optical transparency of the high aspect ratio metal structures at visible wavelength range is comparable to that of ITO glass, while their sheet resistance is more than 3 times lower, which indicates a much higher electrical conductivity of the metal structures. Furthermore, the high aspect ratio metal structures have very high infrared (IR) reflection (90%) for the transverse magnetic (TM) mode, which can lead to the development of fabrication of metallic structures as IR filters for heat control applications. Investigations of interdigitated structures based on the high aspect ratio metal electrodes are ongoing to study the feasibility in smart window applications in light transmission modulation.

Kuang, Ping

2011-05-15

148

Highly reliable ag nanowire flexible transparent electrode with mechanically welded junctions.  

PubMed

Deformation behavior of the Ag nanowire flexible transparent electrode under bending strain is studied and results in a novel approach for highly reliable Ag nanowire network with mechanically welded junctions. Bending fatigue tests up to 500 000 cycles are used to evaluate the in situ resistance change while imposing fixed, uniform bending strain. In the initial stages of bending cycles, the thermally annealed Ag nanowire networks show a reduction in fractional resistance followed by a transient and steady-state increase at later stages of cycling. SEM analysis reveals that the initial reduction in resistance is caused by mechanical welding as a result of applied bending strain, and the increase in resistance at later stages of cycling is determined to be due to the failure at the thermally locked-in junctions. Based on the observations from this study, a new methodology for highly reliable Ag nanowire network is proposed: formation of Ag nanowire networks with no prior thermal annealing but localized junction formation through simple application of mechanical bending strain. The non-annealed, mechanically welded Ag nanowire network shows significantly enhanced cyclic reliability with essentially 0% increase in resistance due to effective formation of localized wire-to-wire contact. PMID:24789010

Hwang, Byungil; Shin, Hae-A-Seul; Kim, Taegeon; Joo, Young-Chang; Han, Seung Min

2014-08-01

149

Control of thickness uniformity and grain size in graphene films for transparent conductive electrodes  

NASA Astrophysics Data System (ADS)

Large-scale and transferable graphene films grown on metal substrates by chemical vapor deposition (CVD) still hold great promise for future nanotechnology. To realize the promise, one of the key issues is to further improve the quality of graphene, e.g., uniform thickness, large grain size, and low defects. Here we grow graphene films on Cu foils by CVD at ambient pressure, and study the graphene nucleation and growth processes under different concentrations of carbon precursor. On the basis of the results, we develop a two-step ambient pressure CVD process to synthesize continuous single-layer graphene films with large grain size (up to hundreds of square micrometers). Scanning electron microscopy and Raman spectroscopy characterizations confirm the film thickness and uniformity. The transferred graphene films on cover glass slips show high electrical conductivity and high optical transmittance that make them suitable as transparent conductive electrodes. The growth mechanism of CVD graphene on Cu is also discussed, and a growth model has been proposed. Our results provide important guidance toward the synthesis of high quality uniform graphene films, and could offer a great driving force for graphene based applications.

Wu, Wei; Yu, Qingkai; Peng, Peng; Liu, Zhihong; Bao, Jiming; Pei, Shin-Shem

2012-01-01

150

Selective growth and integration of silver nanoparticles on silver nanowires at room conditions for transparent nano-network electrode.  

PubMed

Recently, metal nanowires have received great research interests due to their potential as next-generation flexible transparent electrodes. While great efforts have been devoted to develop enabling nanowire electrodes, reduced contact resistance of the metal nanowires and improved electrical stability under continuous bias operation are key issues for practical applications. Here, we propose and demonstrate an approach through a low-cost, robust, room temperature and room atmosphere process to fabricate a conductive silver nano-network comprising silver nanowires and silver nanoparticles. To be more specific, silver nanoparticles are selectively grown and chemically integrated in situ at the junction where silver nanowires meet. The site-selective growth of silver nanoparticles is achieved by a plasmon-induced chemical reaction using a simple light source at very low optical power density. Compared to silver nanowire electrodes without chemical treatment, we observe tremendous conductivity improvement in our silver nano-networks, while the loss in optical transmission is negligible. Furthermore, the silver nano-networks exhibit superior electrical stability under continuous bias operation compared to silver nanowire electrodes formed by thermal annealing. Interestingly, our silver nano-network is readily peeled off in water, which can be easily transferred to other substrates and devices for versatile applications. We demonstrate the feasibly transferrable silver conductive nano-network as the top electrode in organic solar cells. Consequently, the transparent and conductive silver nano-networks formed by our approach would be an excellent candidate for various applications in optoelectronics and electronics. PMID:25285984

Lu, Haifei; Zhang, Di; Ren, Xingang; Liu, Jian; Choy, Wallace C H

2014-10-28

151

Ag-nanowire films coated with ZnO nanoparticles as a transparent electrode for solar cells  

NASA Astrophysics Data System (ADS)

We demonstrate that solution-processible silver-nanowire films coated with zinc-oxide-nanoparticles (ZnO-NPs) can be used as transparent electrodes in organic photovoltaic devices. The ZnO-NP coating acts as electron extraction layer and as encapsulating agent, protecting the wires from oxidation and improving their mechanical stability. Scanning photocurrent microscopy showed photocurrent generation to be more efficient at the active material surrounding the wires. Ultra-violet illumination as present in the solar spectrum was found to enhance photocurrent by improving the ZnO in-layer conductivity through the photoconductive effect. Inverted polythiophene:fullerene devices using ZnO-NP coated silver-nanowires or indium-tin-oxide as transparent electrode reached power conversion efficiencies of 2.4%.

Morgenstern, Frederik S. F.; Kabra, Dinesh; Massip, Sylvain; Brenner, Thomas J. K.; Lyons, Philip E.; Coleman, Jonathan N.; Friend, Richard H.

2011-10-01

152

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

153

High-performance dye-sensitized solar cells with gel-coated binder-free carbon nanotube films as counter electrode  

NASA Astrophysics Data System (ADS)

High-performance dye-sensitized solar cells (DSCs) with binder-free films of carbon nanotubes (CNTs), including single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs), as the counter electrode are reported. The CNT films were fabricated by coating gels, which were prepared by dispersing CNTs in low-molecular-weight poly(ethylene glycol) (PEG) through mechanical grinding and subsequent ultrasonication, on fluorine tin oxide (FTO) glass. PEG was removed from the CNT films through heating. These binder-free CNT films were rough and exhibited good adhesion to substrates. They were used as the counter electrode of DSCs. The DSCs with SWCNT or MWCNT counter electrodes exhibited a light-to-electricity conversion efficiency comparable with that with the conventional platinum (Pt) counter electrode, when the devices were tested immediately after device fabrication. The DSCs with an SWCNT counter electrode exhibited good stability in photovoltaic performance. The efficiency did not decrease after four weeks. On the other hand, DSCs with the MWCNT or Pt counter electrode exhibited a remarkable decrease in the photovoltaic efficiency after four weeks. The high photovoltaic performance of these DSCs is related to the excellent electrochemical catalysis of CNTs on the redox of the iodide/triiodide pair, as revealed by the cyclic voltammetry and ac impedance spectroscopy.

Mei, Xiaoguang; Cho, Swee Jen; Fan, Benhu; Ouyang, Jianyong

2010-10-01

154

Glucose aided preparation of tungsten sulfide/multi-wall carbon nanotube hybrid and use as counter electrode in dye-sensitized solar cells.  

PubMed

The tungsten sulfide/multi-wall carbon nanotube (WS(2)/MWCNT) hybrid was prepared in the presence of glucose by the hydrothermal route. The hybrid materials were used as counter electrode in the dye-sensitized solar cell (DSSC). The results of cyclic voltammetry measurement and electrochemical impedance spectroscopy indicated that the glucose aided prepared (G-A) WS(2)/MWCNT electrode had low charge-transfer resistance (R(ct)) and high electrocatalytic activity for triiodide reduction. The excellent electrochemical properties for (G-A) WS(2)/MWCNT electrode is due to the synergistic effects of WS(2) and MWCNTs, as well as amorphous carbon introduced by glucose. The DSSC based on the G-A WS(2)/MWCNT counter electrode achieved a high power conversion efficiency of 7.36%, which is comparable with the performance of the DSSC using Pt counter electrode (7.54%). PMID:23182023

Wu, Jihuai; Yue, Gentian; Xiao, Yaoming; Huang, Miaoliang; Lin, Jianming; Fan, Leqing; Lan, Zhang; Lin, Jeng-Yu

2012-12-01

155

Ag-nanowire films coated with ZnO nanoparticles as a transparent electrode for solar cells  

Microsoft Academic Search

We demonstrate that solution-processible silver-nanowire films coated with zinc-oxide-nanoparticles (ZnO-NPs) can be used as transparent electrodes in organic photovoltaic devices. The ZnO-NP coating acts as electron extraction layer and as encapsulating agent, protecting the wires from oxidation and improving their mechanical stability. Scanning photocurrent microscopy showed photocurrent generation to be more efficient at the active material surrounding the wires. Ultra-violet

Frederik S. F. Morgenstern; Dinesh Kabra; Sylvain Massip; Thomas J. K. Brenner; Philip E. Lyons; Jonathan N. Coleman; Richard H. Friend

2011-01-01

156

Post-plasma treatment of a carbon nanowall for use as a counter electrode in a dye-sensitized solar cell  

NASA Astrophysics Data System (ADS)

This research investigates plasma-treated carbon nanowalls (CNW) for use as counter electrodes in dye-sensitized solar cells (DSSCs). The CNWs were synthesized on a fluorine-tin-oxide (FTO) glass substrate via microwave plasma-enhanced chemical vapor-deposition (PECVD) using CH4 gas. Then, post-plasma treatments were performed on the CNWs in different plasma environments (using O2, H2 and N2 gas) under the same conditions, after which DSSCs were fabricated using the plasma-treated CNWs as counter electrodes. Scanning electron microscopy (SEM) was performed to obtain cross-sectional and planar images of the CNWs, and Raman spectroscopy was used to analyze the structural characteristics of the post-plasma-treated synthesized CNWs. The energy conversion efficiency was then used to analyze the effect of using the plasma-treated CNWs as counter electrodes in the DSSCs. The DSSC for which the as-deposited CNW was used as a counter electrode showed an energy conversion efficiency of 1.64%, and the DSSC with the H2 postplasma-treated CNW counter electrode showed an energy conversion efficiency of 2.23%. Thus, the DSSC with the H2-treated electrode presented a 36% higher efficiency than the DSSC with the as-deposited CNW electrode.

Jung, Yong Ho; Choi, Won Seok; Hong, Byungyou

2014-08-01

157

Optimization of transparent and reflecting electrodes for amorphous silicon solar cells. Final technical report  

SciTech Connect

Transparent conducting fluorine doped zinc oxide was deposited as thin films on soda lime glass substrates by atmospheric pressure chemical vapor deposition (CVD) at substrate temperatures of 460 to 500 degrees C. The precursors diethylzinc, tetramethylethylenediamine and benzoyl fluoride were dissolved in xylene. This solution was nebulized ultrasonically and then flash vaporized by a carrier gas of nitrogen preheated to 150 degrees C. Ethanol was vaporized separately, and these vapors were then mixed to form a homogeneous vapor mixture. Good reproducibility was achieved using this new CVD method. Uniform thicknesses were obtained by moving the heated glass substrates through the deposition zone. The best electrically and optical properties were obtained when the precursor solution was aged for more than a week before use. The films were polycrystalline and highly oriented with the c-axis perpendicular to the substrate. More than 90% of the incorporated fluorine atoms were electrically active as n-type dopants. The electrical resistivity of the films was as low as 5 x 10/sup -4/ Omega cm. The mobility was about 45 cm /Vs. The electron concentration was up to 3 x 10 %sup20;/cm. The optical absorption of the films was about 3-4% at a sheet resistance of 7 ohms/square. The diffuse transmittance was about 10% at a wavelength of 650 nm. Amorphous ilicon solar cells were deposited using the textured fluorine doped zinc oxide films as a front electrode. The short circuit current was increased over similar cells made with fluorine doped tin oxide, but the open circuit voltages and fill factors were reduced. The voltage was restored by overcoating the fluorine-doped zinc oxide with a thin layer of fluorine-doped tin oxide.

Gordon, R.G.; Kramer, K.; Liang, H.; Liu, X.; Pang, D.; Teff, D.

1998-09-01

158

Improvement of luminous efficacy in plasma display panels by a counter-type electrode configuration with a large gap  

SciTech Connect

The discharge characteristics of plasma display panel with coplanar and counter-type electrode configurations are compared using the numerical modeling and experiment with respect to real and macrocells, respectively. Numerical analysis shows that the ultraviolet (UV) efficiency and driving voltage of counter type at a gap distance of 230 {mu}m are located at similar levels to those of coplanar type at a gap distance of 60 {mu}m. The UV efficiency for counter type is enhanced with the rise of xenon fraction and gap distance, between which the large gap operation is more advantageous to high UV efficiency. The measured temporal evolution of infrared emission reveals that the cathode layer plays an important role in forming the discharge current after the gas breakdown. It is found from the time-averaged visible and infrared emissions for the counter type that as the gap distance becomes larger, the positive column region increases but the sheath regime remains almost unchanged. On the other hand, the variation of gap distance gives a little influence on the average discharge current at the same applied voltage. The UV efficiency is thus greatly improved with the gap distance. When the gap becomes double, the UV efficiency is improved by 75%, which is well agreed with the results predicted in the numerical modeling.

Hur, Min; Kim, Jae Rok; Yi, Jeong Doo; Cho, Yoon Hyoung; Song, Su Bin; Park, Jun Yong; Lee, Han Yong [Display 2 Team, Corporate R and D Center, Samsung SDI Co., Ltd. 428-5, Gongse-ri, Giheung-eup, Yongin-si, Gyeonggi-do 449-577 (Korea, Republic of); CAE Team, Corporate R and D Center, Samsung SDI Co., Ltd. 428-5, Gongse-ri, Giheung-eup, Yongin-si, Gyeonggi-do 449-577 (Korea, Republic of)

2006-06-01

159

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

Microsoft Academic Search

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 200C using various physical deposition methods: BZO

Tadatsugu Minami; Toshihiro Miyata; Jun-ichi Nomoto

2012-01-01

160

Efficient CdS quantum dot sensitized solar cells made using novel Cu2S counter electrode  

NASA Astrophysics Data System (ADS)

A novel Cu2S counter electrode (CE), which is prepared through simple electroplating method, is used to fabricate CdS quantum dot sensitized solar cells. The cells applying our novel CE show high power conversion efficiency in its class, reaching 2.6% under standard AM1.5 illumination, which is higher than those with Platinum CE (1.1%) and brass based Cu2S CE (1.85%). This is due to the novel CE showing superior photoelectrochemical performance and electrocatalytic property indicated by current density-voltage (J-V), the incident photon to current efficiency (IPCE) and the electrochemical impedance spectroscopy (EIS) curves.

Meng, Ke; Surolia, Praveen K.; Byrne, Owen; Thampi, K. Ravindranathan

2014-02-01

161

A new in-situ preparation method to FeS counter electrode for quantum dots-sensitized solar cells  

NASA Astrophysics Data System (ADS)

FeS counter electrode (CE) with the structure of three-dimensional nanospheres for quantum dots-sensitized solar cells (QDSCs) is first fabricated by alternating current (AC) etching the A3 carbon steel and characterized with scanning electron microscope (SEM), Transmission electron microscope (TEM), current-voltage and impedance spectroscopy. The device applying FeS CE achieves a power conversion efficiency of 3.34%, which are much higher than that of using Pt (1.01%) and conventional Cu2S (1.54%). These results indicated that AC provides an efficient, simple and cost-effective method to fabricate CE for QDSCs.

Quan, Linlin; Li, Weiping; Zhu, Liqun; Geng, Huifang; Chang, Xiaowen; Liu, Huicong

2014-12-01

162

Efficiency enhancement for dye-sensitized solar cells with a porous NiO/Pt counter electrode  

NASA Astrophysics Data System (ADS)

Bi-layer counter electrodes made of platinum films (Pt) coated on porous nickel oxide nanosheets (PNO) were investigated for a dye sensitized solar cell (DSSC). The PNO and Pt films were deposited using a chemical bath deposition and a DC sputtering technique, respectively. Connected networks of sputtered Pt on PNO nanosheets significantly enhanced electrocatalytic activities due to the increase in the electroactive areas. The solar conversion efficiency of the FTO/PNO/Pt DSSC was 8.17% in comparison to 7.23% for the FTO/Pt DSSC.

Maiaugree, Wasan; Kongprakaiwoot, Natcharee; Tangtrakarn, Apishok; Saekow, Samarn; Pimanpang, Samuk; Amornkitbamrung, Vittaya

2014-01-01

163

Ordered multimodal porous carbon as highly efficient counter electrodes in dye-sensitized and quantum-dot solar cells.  

PubMed

Ordered multimodal porous carbon (OMPC) was explored as a counter electrode in ruthenium complex dye-sensitized solar cells (DSSCs) and CdSe quantum-dot solar cells (QDSCs). The unique structural characteristics such as large surface area and well-developed three-dimensional (3-D) interconnected ordered macropore framework with open mesopores embedded in the macropore walls make the OMPC electrodes have high catalytic activities and fast mass transfer kinetics toward both triiodide/iodide and polysulfide electrolytes. The efficiency (ca. 8.67%) of the OMPC based DSSC is close to that (ca. 9.34%) of the Pt based one. Most importantly, the QDSC employing OMPC material presents a high efficiency of up to 4.36%, which is significantly higher than those of Pt- and activated carbon based solar cells, ca. 2.29% and 3.30%, respectively. PMID:20695615

Fan, Sheng-Qiang; Fang, Baizeng; Kim, Jung Ho; Jeong, Banseok; Kim, Chulwoo; Yu, Jong-Sung; Ko, Jaejung

2010-08-17

164

Enhanced performance of supported HfO2 counter electrodes for redox couples used in dye-sensitized solar cells.  

PubMed

Mesoporous-graphitic-carbon-supported HfO2 (HfO2 -MGC) nanohybrids were synthesized by using a soft-template route. Characterization and a systematic investigation of the catalytic properties, stability, and catalytic mechanism were performed for HfO2 -MGC counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). The new HfO2 -MGC as a CE in DSSCs showed a surprisingly high efficiency of 7.75 % for the triiodide/iodide redox couple and 3.69 % for the disulfide/thiolate redox couple, greater than the Pt electrode in the corresponding electrolyte system, which opens up a possibility for its practical application. PMID:24399514

Yun, Sining; Pu, Haihui; Chen, Junhong; Hagfeldt, Anders; Ma, Tingli

2014-02-01

165

Low-cost electrospun highly crystalline kesterite Cu2ZnSnS4 nanofiber counter electrodes for efficient dye-sensitized solar cells.  

PubMed

In the present investigation, kesterite Cu2ZnSnS4 (CZTS) nanofibers were obtained by electrospinning process using polyvinylpyrrolidone (PVP) and cellulose acetate (CA) solvent separately. The synthesized CZTS nanofibers were characterized using thermogravimetric analysis (TGA), optical absorption, X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM), micro-Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). Our results showed that the PVP synthesized CZTS nanofibers are a single crystalline while CA assisted CZTS nanofibers are polycrystalline in nature. The optical properties demonstrated that the prepared nanofibers have strong absorption in 300-550 nm range with band gap energy of 1.5 eV. The X-ray and micro-Raman analysis revealed that synthesised nanofibers showing pure phase kesterite CZTS. Further the synthesized CZTS nanofibers were used as counter electrodes for dye-sensitized solar cells (DSSCs). Our results indicate that, PVP-CZTS and CA-CZTS counter electrode based DSSC shows 3.10% and 3.90% respectively. The detailed interfaces of these counter electrodes and DSSCs were analyzed by electrochemical impedance spectroscopic (EIS) measurements for analysis of such high power conversion efficiency. The present study will be helpful for alternative counter electrode for Pt counter electrodes in DSSCs application. We believe that our synthetic method will be helpful for low-cost and efficient thin film photovoltaic technology. PMID:24383575

Mali, Sawanta S; Patil, Pramod S; Hong, Chang Kook

2014-02-12

166

Enhancement of the efficiency of dye-sensitized solar cell with multi-wall carbon nanotubes/polythiophene composite counter electrodes prepared by electrodeposition  

NASA Astrophysics Data System (ADS)

For the purpose of increasing the energy conversion efficiency of dye-sensitized solar cells (DSSCs), multi-wall carbon nanotube (MWCNT)/polythiophene (PTh) composite film counter electrode has been fabricated by electrophoresis and cyclic voltammetry (CV) in sequence. The morphology and chemical structure have been characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), and Raman spectroscopy respectively. The overall energy conversion efficiency of the DSSC employing the MWCNT/PTh composite film has reached 4.72%, which is close to that of the DSSC with a platinum (Pt) counter electrode (5.68%). Compared with a standard DSSC with MWCNT counter electrode whose efficiency is 2.68%, the energy conversion efficiency has been increased by 76.12% for the DSSC with MWCNT/PTh counter electrode. These results indicate that the composite film with high conductivity, high active surface area, and good catalytic properties for I 3- reduction can potentially be used as the counter electrode in a high-performance DSSC.

Luo, Jun; Niu, Hai-jun; Wu, Wen-jun; Wang, Cheng; Bai, Xu-duo; Wang, Wen

2012-01-01

167

Fabrication of transparent conductive oxide-less dye-sensitized solar cells consisting of Ti electrodes by electron-beam evaporation process  

Microsoft Academic Search

In this paper, we report a fabrication process of transparent conductive oxide (TCO)-less dye-sensitized solar cell. In the proposed cell fabrication process, TCO electrode is replaced with Ti electrode. Ti layer is deposited by electron beam evaporation method on the backside of the printed TiO2 layer. Due to the relatively rough surface of TiO2 printing layer, deposited Ti electrode has

Yun-Gi Kim; Choung-Hwan Shim; Dong-Hyun Kim; Hae June Lee; Ho-Jun Lee

168

Understanding interfacial charge transfer between metallic PEDOT counter electrodes and a cobalt redox shuttle in dye-sensitized solar cells.  

PubMed

Conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) doped with iron(III) tris-p-toluenesulfonate (PEDOT:Tos) having metallic conductivity was coated onto fluorine-doped tin oxide (FTO) glass and plain glass substrates and used as a counter electrode (CE) in a dye-sensitized solar cell (DSC) with a [Co(bpy)3](3+/2+) complex redox shuttle. DSCs with PEDOT:Tos/glass CE yielded power conversion efficiencies (PCE) of 6.3%, similar to that of DSCs with platinized FTO glass CE (6.1%). The PEDOT:Tos-based counter electrodes had 5 to 10 times lower charge-transfer resistance than the Pt/FTO CE in DSCs, as analyzed by impedance spectroscopy. More detailed studies in symmetrical CE-CE cells showed that the PEDOT:Tos layers are nanoporous. Not all internal area can be used catalytically under solar cell conditions and effective charge-transfer resistance was similar to that of Pt/FTO. PMID:24410094

Park, Byung-wook; Pazoki, Meysam; Aitola, Kerttu; Jeong, Seunghee; Johansson, Erik M J; Hagfeldt, Anders; Boschloo, Gerrit

2014-02-12

169

Influence of Cu Vacancy on Knit Coir Mat Structured CuS as Counter Electrode for Quantum Dot Sensitized Solar Cells.  

PubMed

Knit-coir-mat-like structured CuS thin films prepared by chemical bath deposition with different time duration were used as counter electrode in qunatum dot sensitized solar cells. The film deposited at 4 h exhibited better electrochemical and photovoltaic performance with JSC, VOC, and FF values of 14.584 mA cm(-2), 0.566 V, and 54.57% and efficiency of 4.53%. From the UV-vis absorption spectra, it is observed that CuS thin film exhibits free carrier intraband absorption in the longer wavelengh region. The enhanced performance of CuS counter electrodes is due to Cu vacancies with increased S composition, and the quasi-Fermi energy level in semiconductors with respect to electrolyte redox potential is one of the causes that affects the electrocatalytic activity of counter electrodes. PMID:25341851

Savariraj, A Dennyson; Viswanathan, Kodakkal Kannan; Prabakar, Kandasamy

2014-11-26

170

N-Doped graphene nanoplatelets as superior metal-free counter electrodes for organic dye-sensitized solar cells.  

PubMed

Highly efficient counter electrodes (CEs) for dye-sensitized solar cells (DSSCs) were developed using thin films of scalable and high-quality, nitrogen-doped graphene nanoplatelets (NGnP), which was synthesized by a simple two-step reaction sequence. The resultant NGnP was deposited on fluorine-doped SnO2 (FTO)/glass substrates by using electrospray (e-spray) coating, and their electrocatalytic activities were systematically evaluated for Co(bpy)3(3+/2+) redox couple in DSSCs with an organic sensitizer. The e-sprayed NGnP thin films exhibited outstanding performances as CEs for DSSCs. The optimized NGnP electrode showed better electrochemical stability under prolonged cycling potential, and its Rct at the interface of the CE/electrolyte decreased down to 1.73 ? cm(2), a value much lower than that of the Pt electrode (3.15 ? cm(2)). The DSSC with the optimized NGnP-CE had a higher fill factor (FF, 74.2%) and a cell efficiency (9.05%), whereas those of the DSSC using Pt-CE were only 70.6% and 8.43%, respectively. To the best of our knowledge, the extraordinarily better current-voltage characteristics of the DSSC-NGnP outperforming the DSSC-Pt for the Co(bpy)3(3+/2+) redox couple (in paticular, FF and short circuit current, Jsc) is highlighted for the first time. PMID:23656316

Ju, Myung Jong; Kim, Jae Cheon; Choi, Hyun-Jung; Choi, In Taek; Kim, Sang Gyun; Lim, Kimin; Ko, Jaejung; Lee, Jae-Joon; Jeon, In-Yup; Baek, Jong-Beom; Kim, Hwan Kyu

2013-06-25

171

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

172

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

173

Effect of purity on the electro-optical properties of single wall nanotube-based transparent conductive electrodes  

SciTech Connect

We present a detailed assessment of centrifugation technique for purification of single wall carbon nanotubes (SWCNTs) for application as transparent conductive electrodes. As- grown and highly-purified SWCNTs were dispersed in surfactants by ultrasonication, and then centrifuged to selectively remove carbonaceous and metal impurities. The centrifuged supernatant suspensions were made into thin films by transferring filtrated nanotube coat- ings onto glass slides. The absorbance and resistance of nanotube coatings were measured, and their optical purity level estimated from a comparison of the area of the near-infrared S22 SWCNT optical absorption band relative to the area of the background. The single-step centrifugation process is shown to purify laser-vaporization grown SWCNTs from an initial optical purity of 0.10 to an averaged purity of 0.23, with an 8.8% yield, which is comparable to other purification techniques. The quality of transparent conductive electrodes esti- mated as a ratio of visible-spectrum absorbance to sheet conductivity is improved by a fac- tor of 12 upon purification.

Garrett, Matthew P [ORNL; Ivanov, Ilia N [ORNL; Geohegan, David B [ORNL; Hu, Bin [ORNL

2013-01-01

174

Vertically aligned single-walled carbon nanotubes as low-cost and high electrocatalytic counter electrode for dye-sensitized solar cells.  

PubMed

A novel dye-sensitized solar cell (DSSC) structure using vertically aligned single-walled carbon nanotubes (VASWCNTs) as the counter electrode has been developed. In this design, the VASWCNTs serve as a stable high surface area and highly active electrocatalytic counter-electrode that could be a promising alternative to the conventional Pt analogue. Utilizing a scalable dry transfer approach to form a VASWCNTs conductive electrode, the DSSCs with various lengths of VASWCNTs were studied. VASWCNTs-DSSC with 34 ?m original length was found to be the optimal choice in the present study. The highest conversion efficiencies of VASWCNTs-DSSC achieved 5.5%, which rivals that of the reference Pt DSSC. From the electrochemical impedance spectroscopy analysis, it shows that the new DSSC offers lower interface resistance between the electrolyte and the counter electrode. This reproducible work emphasizes the promise of VASWCNTs as efficient and stable counter electrode materials in DSSC device design, especially taking into account the low-cost merit of this promising material. PMID:21770421

Dong, Pei; Pint, Cary L; Hainey, Mel; Mirri, Francesca; Zhan, Yongjie; Zhang, Jing; Pasquali, Matteo; Hauge, Robert H; Verduzco, Rafael; Jiang, Mian; Lin, Hong; Lou, Jun

2011-08-01

175

Time resolved optical emission images of an atmospheric pressure plasma jet with transparent electrodes  

SciTech Connect

We study development of plasma packages in atmospheric pressure plasma jet from their formation as a discharge close to the instantaneous cathode, following their motion between and inside the electrodes up to their emergence at the edge of the glass tube and formation of a plasma bullet. Inside both electrodes, plasma is concentrated close to the walls and is bright, while outside it is located at the axis. This paper opens issues of the geometry of electrodes, fields, and atomic processes, allowing some predictions to be made about pertinent mechanisms.

Puac, N.; Maletic, D.; Lazovic, S.; Malovic, G.; Petrovic, Z. Lj. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Dordevic, A. [School of Electrical Engineering, University of Belgrade, Bul. kralja Aleksandra 73, 11000 Belgrade (Serbia)

2012-07-09

176

Liquid crystal devices incorporating transparent Zn, Sn co-doped In2O3 electrodes prepared by direct inkjet-printing of nanosized particles  

NASA Astrophysics Data System (ADS)

We demonstrate inkjet-printed transparent Zn, Sn co-doped In2O3 (IZTO) films using nanosized IZTO ink as a transparent electrode for liquid crystal (LC) devices. By adjusting the IZTO droplet pitch and line pitch, we can produce directly patterned IZTO electrodes without using a conventional photolithography process. Effective connections between IZTO nanoparticles created by a rapid thermal annealing process resulted in a sheet resistance of 200 ?/square and an optical transmittance of 89.45%, which is acceptable for LC cell fabrication. Stable and reliable electro-optical performance of the twisted nematic LC cells fabricated on the inkjet-printed IZTO films indicates that a directly patterned IZTO film formed by inkjet printing is a promising option for creating printable transparent electrodes for cost-efficient LC cells.

Park, Kyung-Won; Kang, Sin-Bi; Jeong, Jin-A.; Choi, Suk-Won; Kim, Jihoon; You, In-Kyu; Yang, Yong Suk; Kim, Han-Ki

2013-04-01

177

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

178

A dual function of high performance counter-electrode for stable quasi-solid-state dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

A dual function polymer hybrid material poly(3,4-ethylenedioxythiophene) (PEDOT)-poly(acrylic acid) (PAA)-poly(styrenesulfonate) (PSS) was fabricated both as a counter electrode (CE) for I3- reduction and for storage of the liquid electrolyte in quasi-solid-state dye-sensitized solar cells (QS-DSSCs). To enhance the electrocatalytic activity of the nano-PEDOT CE and to improve the ionic conductivity of the three-dimensional (3D) PAA-PSS network, the columnar PEDOT was electropolymerized through the 3D PAA-PSS network. The QS-DSSC showed a high photovoltaic conversion efficiency of 6.35% under full sunlight illumination (100 mW cm-2, AM1.5 G), which reduced to 6.03% after 100 days, indicating this QS-DSSC had a relatively good long-term stability.

Xiao, Yaoming; Wu, Jihuai; Lin, Jeng-Yu; Yue, Gentian; Lin, Jianming; Huang, Miaoliang; Lan, Zhang; Fan, Leqing

2013-11-01

179

Platinum-free binary co-ni alloy counter electrodes for efficient dye-sensitized solar cells.  

PubMed

Dye-sensitized solar cells (DSSCs) have attracted growing interest because of their application in renewable energy technologies in developing modern low-carbon economies. However, the commercial application of DSSCs has been hindered by the high expenses of platinum (Pt) counter electrodes (CEs). Here we use Pt-free binary Co-Ni alloys synthesized by a mild hydrothermal strategy as CE materials in efficient DSSCs. As a result of the rapid charge transfer, good electrical conduction, and reasonable electrocatalysis, the power conversion efficiencies of Co-Ni-based DSSCs are higher than those of Pt-only CEs, and the fabrication expense is markedly reduced. The DSSCs based on a CoNi0.25 alloy CE displays an impressive power conversion efficiency of 8.39?%, fast start-up, multiple start/stop cycling, and good stability under extended irradiation. PMID:25146894

Chen, Xiaoxu; Tang, Qunwei; He, Benlin; Lin, Lin; Yu, Liangmin

2014-09-26

180

Indium tin oxide-free semi-transparent inverted polymer solar cells using conducting polymer as both bottom and top electrodes  

Microsoft Academic Search

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is investigated as a transparent cathode to replace indium tin oxide (ITO) in inverted polymer solar cells. Increasing the thickness of the PEDOT:PSS electrode leads to a reduction in transparency and sheet resistance which lowers the photocurrent but increases the fill factor of the solar cells. The offset of photocurrent and fill factor as the thickness is increased

Steven K. Hau; Hin-Lap Yip; Jingyu Zou; Alex K.-Y. Jen

2009-01-01

181

Inverted semi-transparent organic solar cells with spray coated, surfactant free polymer top-electrodes  

Microsoft Academic Search

Depositing a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) buffer layer or top-electrode from aqueous solution on a non-polar active layer in inverted organic solar cells is commonly considered a very challenging task. In this work we utilize spray deposited PEDOT:PSS seeds to effectively reduce the surface free energy atop the active layer in poly-hexylthiophene polymer solar cells before applying a PEDOT:PSS top-electrode. Though aqueous

Alexander Colsmann; Manuel Reinhard; Tae-Hyuk Kwon; Christian Kayser; Felix Nickel; Jens Czolk; Uli Lemmer; Noel Clark; Jacek Jasieniak; Andrew B. Holmes; David Jones

182

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

183

Reduced graphene oxide-TaON composite as a high-performance counter electrode for Co(bpy)3(3+/2+)-mediated dye-sensitized solar cells.  

PubMed

We report herein the investigation of TaON nanoparticles incorporating a reduced graphene oxide (RGO) nanocomposite as a counter electrode for application in Co(bpy)3(3+/2+) (bpy = 2,2'-bipyridine)-mediated dye-sensitized solar cells (DSSCs). The RGO-TaON nanocomposite has been prepared by mixing graphene oxide (GO) and presynthesized TaON nanoparticles in ethanol/water followed by the facile hydrazine hydrate reduction of GO to RGO. Compared with RGO or TaON alone, the RGO-TaON nanocomposite shows a much higher electrocatalytic activity for the reduction of Co(bpy)3(3+) species owing to synergistic effects, resulting in significantly improved solar-cell performance when it is applied as the counter electrode in DSSCs. An efficiency of 7.65% for the DSSC with the RGO-TaON counter electrode is obtained, competing with the efficiency produced by the Pt counter electrode; additionally, the former exhibits a much better electrochemical stability than the latter in a Co(bpy)3(3+/2+) acetonitrile solution. PMID:23855746

Li, Yan; Wang, Hong; Feng, Quanyou; Zhou, Gang; Wang, Zhong-Sheng

2013-08-28

184

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

185

A Three-Dimensional Transparent Electrode Structure With Al-Doped ZnO Nanorods  

Microsoft Academic Search

ZnO nanorod arrays on a transparent indium tin ox- ide\\/glass substrate were synthesized using a hydrothermal method. The tip diameters of the fabricated ZnO nanorods varied between 20 and 30 nm with lengths of 1 ?m. Addition of Al 3+ ions to the reaction solution produced Al-doped ZnO nanorods. The morphol- ogy and crystallinity of Al-doped ZnO nanorods were investigated

Nam-Hyo Kim; Seung-Ho Jung; Jong Hwan Park; Kun-Hong Lee; Kilwon Cho

2011-01-01

186

Vertical Type Organic Device Using Thin-Film ZnO Transparent Electrode  

Microsoft Academic Search

We propose a double heterojunction type organic light emitting diodes (OLED) using zinc oxide (ZnO) films, which works as a transparent and electron injection layer. The crystal structure of the ZnO films as a function of Ar\\/O2 flow ratio and the basic characteristics of the OLED depending on the ZnO sputtering conditions are investigated. Excellent characteristics of novel OLED were

Hiroyuki Iechi; Takeshi Okawara; Masatoshi Sakai; Masakazu Nakanura; Kazuhiro Kudo

2004-01-01

187

FTO-free counter electrodes for dye-sensitized solar cells using carbon nanosheets synthesised from a polymeric carbon source.  

PubMed

Highly conductive carbon nanosheets (CNSs) are fabricated using a polymeric carbon source and subsequently applied as the counter electrodes (CNS-CEs) for dye-sensitized solar cells (DSSCs). The CNSs have a similar structure to multilayered graphene, and their high electrical conductivity and electrocatalytic activity enable them to have a dual-function as both CEs and charge supporting electrodes. CNSs form a unique CE material that functions successfully while being metal- and fluorine doped tin oxide (FTO)-free and allowing DSSCs to achieve ?5% power conversion efficiency. The chemical structure, electrical properties, electrocatalytic activity, and work function of the CNS-CEs prepared under various conditions of carbonization are investigated, and their effects on the performance of the corresponding DSSCs are discussed. Carbonization temperature is shown to have influenced the size of graphitic domains and the presence of heteroatoms and functional groups in CNS-CEs. The change in the graphitic domain size has a marginal influence on the work function of the CNS-CEs and the overpotential for the reduction of the redox couples (I(-)/I3(-)). However, the electrical conductivity of CNS-CEs and the charge transfer resistance at CE/electrolyte interfaces in the DSSCs are considerably influenced by the carbonization condition. Our study shows that CNSs serve as efficient, FTO-free CE materials for DSSCs, and they are appropriate materials with which the effects of the chemical/physical properties of graphene-based materials on the electrode performance of various electrochemical devices may be studied. PMID:25026395

Akbar, Zico Alaia; Lee, Jae-Seon; Kang, Jinhyeon; Joh, Han-Ik; Lee, Sungho; Jang, Sung-Yeon

2014-09-01

188

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

189

Diffused transmission and texture-induced defect with transparent conducting oxide front electrode of amorphous silicon solar cell  

NASA Astrophysics Data System (ADS)

Highly textured transparent conducting front electrode (TFE) can enhance light trapping; however, we observed an improved performance of a solar cell by nanometer level modification of surface texture. A 40 nm thick aluminum doped zinc oxide was sputter deposited at an oblique flux on the textured fluorine doped tin oxide TFE, and a TFE double layer was used for the front electrode of solar cells. The cells fabricated on these modified TFEs exhibited an increased open circuit voltage, enhancement in short circuit current density and an increase in fill factor that reached up to 74% because of reduced series resistance of the cell. The surface texture of the TFE was modified with various angular fluxes of the zinc oxide sputter particle, which shows lower texture-induced-surface defect, higher work function. These are thought to have helped in improving the performance of the thin-film solar cells. However, at a near normal angular flux of the zinc oxide sputter particle, light trapping was observed to have reduced significantly, leading to a significant reduction in current density of the cell.

Park, Hyeongsik; Iftiquar, S. M.; Kim, Hee Won; Lee, Jaehyeong; Le, Anh Huy Tuan; Yi, Junsin

2013-11-01

190

Laser direct imaging of transparent indium tin oxide electrodes using high speed stitching techniques  

NASA Astrophysics Data System (ADS)

To accomplish an electrode patterning in large area, we present a high speed stitching technique used in an ultraviolet laser processing system and investigate the interaction between laser beams and indium tin oxide (ITO) thin films deposited on glass substrates. After optimizing the process parameters of the laser direct imaging (LDI) for the large-area electrode patterning, the ablated lines looked like regularly fish-scale marks of about a 40 ?m diameter and a 120 nm depth around the processing path. The parameters includes the laser power of 1W, the scanning speed of galvanometers of 800 mm/s, and the laser pulse repetition frequency of 50 kHz. Moreover, the resistance value of the ablated ITO thin film is larger than 200M? that is electrically insulated from the other regions of electrode structure. LDI technology with UV laser beam has great potential applications in patterning on wafer or sapphire substrates and patterning a conductive layer deposited on the touch panels for semiconductor and optoelectric industries, respectively.

Cheng, Pi-Ying; Hsiao, Wen-Tse; Chung, Chien-Kai; Tseng, Shih-Feng; Liao, Ien-Chang

2014-09-01

191

Generation of transparent conductive electrodes by laser consolidation of LIFT printed ITO nanoparticle layers  

NASA Astrophysics Data System (ADS)

Indium tin oxide (ITO) is one of the few materials available that display a high transparency in the visible wavelength region and at the same time can conduct electrical currents. Thus it is widespread in many optoelectronic applications such as displays or solar cells. Layers of this material are commonly deposited by vacuum deposition methods which are not compatible with inexpensive production methods such as roll-to-roll processing or printed electronics in general. In this work, we demonstrate the generation of arbitrarily shaped ITO layers by laser induced forward transfer of ITO nanoparticles. The transferred particle ink volumes range in the sub picoliter regime. Feature sizes as small as 20 ?m are produced without any outward flow or "coffee-stain" effects. Furthermore, the feasibility of excimer laser consolidation of these nanoparticulate layers in ambient air for the generation of dense ITO films is shown. Conductivities of over 4000 ?-1 m-1 were achieved. The presented methods are a promising alternative for the generation of transparent conducting layers for the inexpensive production of optoelectronics.

Baum, M.; Kim, H.; Alexeev, I.; Piqu, A.; Schmidt, M.

2013-06-01

192

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

193

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

2014-01-01

194

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

195

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

196

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

197

Correlation between microstructure and property of electroless deposited Pt counter electrodes on plastic substrate for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Flexible Pt counter electrodes (CEs) were prepared on indium-doped tin oxide coated polyethylene naphthalate (ITO-PEN) substrate by electroless deposition. The correlation between the microstructure and the property of the Pt CEs was investigated. Results showed that isolated Pt nanoparticles were uniformly distributed on the ITO surface at a short deposition duration, and then grew with the deposition duration, leading to the interconnection of adjacent Pt nanoparticles. The interconnection of Pt nanoparticles was beneficial to the electrical property of the Pt CEs, while it was unfavorable to the electrocatalytic property of the Pt CEs. A microstructure model was proposed to explain the correlation between the microstructure and the property of the Pt CEs. In addition, the Pt CEs showed low charge transfer resistance (1.66-0.58 ? cm 2), which was comparable to that (1.16 ? cm 2) of the conventional sputtered Pt CE. The high electrocatalytic property of the electroless deposited Pt CEs makes the assembled DSCs present comparable energy conversion efficiency of the DSCs using sputtered Pt CE.

He, Xue-Long; Liu, Mei; Yang, Guan-Jun; Fan, Sheng-Qiang; Li, Chang-Jiu

2011-12-01

198

Dye-sensitized solar cell with a pair of carbon-based electrodes  

NASA Astrophysics Data System (ADS)

We have fabricated a dye-sensitized solar cell (DSSC) with a pair of carbon-based electrodes using a transparent, conductive carbon nanotubes (CNTs) film modified with ultra-thin titanium-sub-oxide (TiOx) as the working electrode and a bilayer of conductive CNTs and carbon black as the counter electrode. Without TiOx modification, the DSSC is almost nonfunctional whereas the power conversion efficiency (PCE) increases significantly when the working electrode is modified with TiOx. The performance of the cell could be further improved when the carbon black film was added on the counter electrode. The improved efficiency can be attributed to the inhibition of the mass recombination at the working electrode/electrolyte interface by TiOx and the acceleration of the electron transfer kinetics at the counter electrode by carbon black. The DSSC with a pair of carbon-based electrodes gives the PCE of 1.37%.

Kyaw, Aung Ko Ko; Tantang, Hosea; Wu, Tao; Ke, Lin; Wei, Jun; Demir, Hilmi Volkan; Zhang, Qichun; Sun, Xiao Wei

2012-04-01

199

Full Printable Processed Mesoscopic CH3NH3PbI3/TiO2 Heterojunction Solar Cells with Carbon Counter Electrode  

NASA Astrophysics Data System (ADS)

A mesoscopic methylammonium lead iodide (CH3NH3PbI3) perovskite/TiO2 heterojunction solar cell is developed with low-cost carbon counter electrode (CE) and full printable process. With carbon black/spheroidal graphite CE, this mesoscopic heterojunction solar cell presents high stability and power conversion efficiency of 6.64%, which is higher than that of the flaky graphite based device and comparable to the conventional Au version.

Ku, Zhiliang; Rong, Yaoguang; Xu, Mi; Liu, Tongfa; Han, Hongwei

2013-11-01

200

Facile fabrication of polypyrrole\\/functionalized multiwalled carbon nanotubes composite as counter electrodes in low-cost dye-sensitized solar cells  

Microsoft Academic Search

This paper reports facile fabrication of polypyrrole (Ppy)\\/functionalized multiwalled carbon nanotube (f-MWCNT) nanocomposite films on rigid fluorine-doped tin oxide (FTO) and flexible ITO-coated polyethylene naphthalate (PEN) substrates by a drop casting method, and their application as counter electrodes in dye-sensitized solar cells (DSSCs). The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements of this solution processed Ppy\\/f-MWCNT nanocomposite film

Shengjie Peng; Yongzhi Wu; Peining Zhu; Velmurugan Thavasi; Subodh G. Mhaisalkar; Seeram Ramakrishna

2011-01-01

201

Full Printable Processed Mesoscopic CH3NH3PbI3/TiO2 Heterojunction Solar Cells with Carbon Counter Electrode  

PubMed Central

A mesoscopic methylammonium lead iodide (CH3NH3PbI3) perovskite/TiO2 heterojunction solar cell is developed with low-cost carbon counter electrode (CE) and full printable process. With carbon black/spheroidal graphite CE, this mesoscopic heterojunction solar cell presents high stability and power conversion efficiency of 6.64%, which is higher than that of the flaky graphite based device and comparable to the conventional Au version. PMID:24185501

Ku, Zhiliang; Rong, Yaoguang; Xu, Mi; Liu, Tongfa; Han, Hongwei

2013-01-01

202

Porous, single crystalline titanium nitride nanoplates grown on carbon fibers: excellent counter electrodes for low-cost, high performance, fiber-shaped dye-sensitized solar cells.  

PubMed

An excellent, platinum free fiber counter electrode (CE) was successfully fabricated, consisting of porous, single crystalline titanium nitride (TiN) nanoplates grown on carbon fibers (CF). The fiber-shaped dye-sensitized solar cells (FDSSCs) based on the TiN-CF CE show a high conversion efficiency of 7.20%, comparable or even superior to that of the Pt wire (6.23%). PMID:25068835

Chen, Liang; Dai, Hui; Zhou, Yong; Hu, Yingjie; Yu, Tao; Liu, Jianguo; Zou, Zhigang

2014-10-23

203

Optimization of transparent and reflecting electrodes for amorphous silicon solar cells  

SciTech Connect

The specific objectives of this research are to: (1) Deposit and characterize textured zinc oxide with improved conductivities (less than 8 ohms/square sheet resistance) and optical transmission (greater than 85% for 450 to 700 nm), for use as front and back contacts in hydrogenated amorphous silicon p-i-n devices. Study the surface morphology of zinc oxide films deposited by chemical vapor deposition at atmospheric pressure (APCVD), their crystallite sizes, shapes and orientations, and their nucleation (early growth) as a function of chemical precursors and reaction conditions. Optimize the growth process to produce structures that provide good light trapping in an amorphous silicon film deposited on the zinc oxide film. The films must have good adhesion to glass substrates. (2) Study the deposition rate of zinc oxide films as a function of temperature, and concentration and types of reactants. Maximize the growth rate, subject to the conditions of maintaining satisfactory film properties, including high transparency (85%), high conductivity (8 ohm/square sheet resistance), and good light trapping. (3) Develop techniques for deposition of fluorinated zinc oxide films by APCVD on amorphous silicon films in the temperature range of 250-280C for use as back contacts. (4) Deposit titanium nitride films at a temperature of about 250C by APCVD on amorphous silicon as diffusion barrier, and then deposit highly reflective metals such as aluminum or silver. Anneal samples and test for metal diffusion through the TiN into the silicon. Optimize the TiN film for minimum diffusion consistent with maintaining desirable TiN film properties. (5) Incorporate the front and back contacts including the TiN barrier layer developed under this research into amorphous silicon p-i-n devices and determine the film parameters that provide the greatest improvement in the device solar energy conversion efficiency. 23 refs., 18 figs., 2 tabs.

Gordon, R.G.; Hu, Jianhua; Musher, J.; Giunta, C. (Harvard Univ., Cambridge, MA (USA). Dept. of Chemistry)

1991-02-01

204

Development of bifacial inverted polymer solar cells using a conductivity-controlled transparent PEDOT:PSS and a striped Au electrode on the hole collection side  

NASA Astrophysics Data System (ADS)

An inverted bifacial polymer solar cell was developed using a conductivity-controlled transparent poly(3,4-ethylenedioxylenethiophene):poly(4-styrene sulfonic acid) (PEDOT:PSS) as a hole collection layer and a striped Au electrode with a large open aperture ratio (Rap) as a hole collection electrode. We investigated the performance of the device by varying the interelectrode distance of the striped Au electrode and the sheet resistance of the PEDOT:PSS film. The device using untreated Clevios P (PEDOT:PSS) showed a maximum electric output (Pw) in the Rap range of 50 to 65%. When alcohol-treated Clevios P (Clevios P+) with a lower electrical resistance was used, the maximum Pw increased by 40% compared with that of the device using Clevios P. The maximum Pw was obtained in the Rap range of 84% as the hole collection efficiency of the striped Au electrode improved with the decreased sheet resistance of the PEDOT:PSS.

Kuwabara, Takayuki; Katori, Shinji; Arima, Kazuhiro; Omura, Yoshihiro; Yamaguchi, Takahiro; Taima, Tetsuya; Takahashi, Kohshin

2014-02-01

205

Solution-Processable Transparent Conductive Hole Injection Electrode for OLED SSL  

SciTech Connect

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 10ohms/sq with a transmission (including the glass substrate) of higher than 85%. The first phase of the project focused on the implementation of this nanowire layer with a hole-injection-layer (HIL) which has been developed at Plextronics and has been shown to provide good stability and efficiency in conventional OLED devices. We modified the HIL solution such that it coated reasonably well with suitable surface morphology so that actual devices can be manufactured. During the second phase we investigated the hole-injection and stability of hole-onlydevices. We determined that the use of the nanowire network as anode does not introduce an additional degradation mechanism since the observed device characteristics did not differ from those made with ITO anode. We then proceeded to make actual OLED devices with this nanowire / HIL stack and achieved device characteristics similar state-of-the-art OLED devices with a single junction. In order to gain traction with potential OLED manufacturers, we decided to contract Novaled to prepare large-area demonstrators for us. For these devices, we used an allevaporated stack, i.e. we did use Novaled??s HIL material instead of Plextronics??. We successfully fabricated demonstrators with an area of 25cm2 with a double or triple junction stack. Minor stack optimizations were necessary to achieve efficacies and lifetime equivalent with ITO devices made with the same devices stack. Due to the reduced microcavity effect, the color of the emitted light is significantly more stable with respect to the viewing angle compared to ITO devices. This fact in conjunction with the promise of lower production cost due to the elimination of the ITO sputtering process and the direct patterning of the anode layer are the obvious advantages of this technology. The project has shown that this nanowire technology is a viable option to achieve OLED devices with good lifetime and efficiency and we are currently working with manufacturers to utilize this technology in a production setting.

None

2012-07-15

206

Enhancement of the effectiveness of graphene as a transparent conductive electrode by AgNO3 doping  

NASA Astrophysics Data System (ADS)

Single-layer graphene sheets have been synthesized by using chemical vapor deposition, and subsequently doped with AgNO3 at various doping concentrations (nD) from 5 to 50 mM. Atomic force microscopy and field emission scanning electron microscopy images reveal the formation of 10-100 nm Ag particles on the graphene surface after doping. The type of n doping is confirmed by analyzing the nD-dependent behaviors of Raman scattering and the work function of the doped graphene films. The sheet resistance monotonically decreases to 173 ?/sq with the increase of nD to 50 mM, and the transmittance is reduced by only about 3% for the highest nD. At nD = 10 mM optimized doped graphene layers with a sheet resistance of 202 ?/sq and a transmittance of 96% are obtained, resulting in a maximum DC conductivity/optical conductivity ratio (?DC/?OP) of 45.5, much larger than the minimum industry standard (?DC/?OP = 35) for transparent conductive electrodes.

Shin, Dong Hee; Lee, Kyeong Won; Lee, Jae Sung; Kim, Ju Hwan; Kim, Sung; Choi, Suk-Ho

2014-03-01

207

Improved optoelectronics properties of ITO-based transparent conductive electrodes with the insertion of Ag/Ni under-layer  

NASA Astrophysics Data System (ADS)

ITO-based transparent conductive electrodes (TCE) with Ag/Ni thin metal under-layer were deposited on Si and glass substrates by thermal evaporator and RF magnetron sputtering system. Ceramic ITO with purity of 99.99% and In2O3:SnO2 weight ratio of 90:10 was used as a target at room temperature. Post-deposition annealing was performed on the TCE at moderate temperature of 500 C, 600 C and 700 C under N2 ambient. It was observed that the structural properties, optical transmittance, electrical characteristics and surface morphology were improved significantly after the post-annealing process. Post-annealed ITO/Ag/Ni at 600 C shows the best quality of TCE with figure-of-merit (FOM) of 1.5 10-2 ?-1 and high optical transmittance of 83% at 470 nm as well as very low electrical resistivity of 4.3 10-5 ?-cm. The crystalline quality and surface morphological plays an important role in determining the quality of the TCE multilayer thin films properties.

Ali, Ahmad Hadi; Abu Bakar, Ahmad Shuhaimi; Hassan, Zainuriah

2014-10-01

208

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

209

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

210

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

211

Transparent Zn-Doped In2O3 Electrode Prepared by Radio Frequency Facing Target Sputtering for Flexible Dye-Sensitized Solar Cells  

Microsoft Academic Search

For the application to transparent electrode in flexible dye-sensitized solar cells (DSSCs), Zn-doped In2O3 (In2O3:Zn) thin films have been fabricated on polyethylene naphthalate (PEN) substrate by the radio frequency facing target sputtering method, and their characteristics have been investigated as a function of deposition pressure. X-ray diffraction study reveal that the structure of In2O3:Zn thin films is amorphous nature. The

Young Cheol Choi; Han Jae Shin; Dong Cheul Han; Kwang-Soon Ahn; Jae Hong Kim; Do Kyung Lee

2011-01-01

212

Studies on aluminum-doped ZnO films for transparent electrode and antireflection coating of ?-FeSi 2 optoelectronic devices  

Microsoft Academic Search

?-FeSi2 can be used for various optoelectronic devices owing to its superior material features including high optical absorption coefficient and direct band gap of about 0.8 eV. Due to its high refractive index (>5.6), however, suitable antireflection coating (ARC) is necessary for practical device applications. In order to increase the effective areas of optoelectronic devices, transparent electrodes should be also

Teruhisa Ootsuka; Zhengxin Liu; Masato Osamura; Yasuhiro Fukuzawa; Ryo Kuroda; Yasuhito Suzuki; Naotaka Otogawa; Takahiro Mise; Shinan Wang; Yasushi Hoshino; Yasuhiko Nakayama; Hisao Tanoue; Yunosuke Makita

2005-01-01

213

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

214

Top-illuminated dye-sensitized solar cells with a room-temperature-processed ZnO photoanode on metal substrates and a Pt-coated Ga-doped ZnO counter electrode  

Microsoft Academic Search

We report on top-illuminated, fluorine tin oxide\\/indium tin oxide-free (FTO\\/ITO-free), dye-sensitized solar cells (DSCs) using room-temperature-processed ZnO layers on metal substrates as the working electrodes and Pt-coated Ga-doped ZnO layers (GZO) as the counter electrodes. These top-illuminated DSCs with GZO render comparable efficiency to those employing commercial FTO counter electrodes. Despite a lower current density, the top-illuminated DSCs result in

A. K. K. Kyaw; X. W. Sun; J. L. Zhao; J. X. Wang; D. W. Zhao; X. F. Wei; X. W. Liu; H. V. Demir; T. Wu

2011-01-01

215

NiSe2 as an efficient electrocatalyst for a Pt-free counter electrode of dye-sensitized solar cells.  

PubMed

Nickel diselenide (NiSe(2)) has been synthesized and applied as a counter electrode (CE) of dye-sensitized solar cells (DSSCs) for the first time, which displays remarkable catalytic activity in the reduction of I(3)(-). The DSSC with a NiSe(2) CE produces a higher power conversion efficiency (8.69%) than that (8.04%) of the cell with a Pt CE under the same conditions. A new method for comparing the catalytic activity has also been proposed. PMID:23321537

Gong, Feng; Xu, Xin; Li, Zhuoqun; Zhou, Gang; Wang, Zhong-Sheng

2013-02-18

216

Light Induced Water Oxidation on Cobalt-Phosphate (Co-Pi) Catalyst Modified Semi-Transparent, Porous SiO2-BiVO4 Electrodes  

SciTech Connect

A facile and simple procedure for the synthesis of semi-transparent and porous SiO{sub 2}-BiVO{sub 4} electrodes is reported. The method involves a surfactant assisted metal-organic decomposition at 500 C. An earth abundant oxygen evolution catalyst (OEC), cobalt phosphate (Co-Pi), has been used to modify the SiO{sub 2}-BiVO{sub 4} electrode by electrodeposition (ED) and photoassisted electrodeposition (PED) methods. Modified electrodes by these two methods have been examined for light induced water oxidation and compared to the unmodified SiO{sub 2}-BiVO{sub 4} electrodes by various photoelectrochemical techniques. The PED method was a more effective method of OEC preparation than the ED method as evidenced by an increased photocurrent magnitude during photocurrent-potential (I-V) characterizations. Electrode surfaces catalyzed by PED exhibited a very large cathodic shift (420 mV) in the onset potential for water oxidation. The chopped-light I-V measurements performed at different intervals over 24-hour extended testing under illumination and applied bias conditions show a fair photostability for PED Co-Pi modified SiO{sub 2}-BiVO{sub 4}.

Pilli, S. K.; Deutsch, T. G.; Furtak, T. E.; Turner, J. A.; Brown, L. D.; Herring, A. M.

2012-04-21

217

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

218

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 TiOSO4xH2O 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

219

Platinum-Free Counter Electrode Comprised of Metal-Organic-Framework (MOF)-Derived Cobalt Sulfide Nanoparticles for Efficient Dye-Sensitized Solar Cells (DSSCs)  

PubMed Central

We fabricated a highly efficient (with a solar-to-electricity conversion efficiency (?) of 8.1%) Pt-free dye-sensitized solar cell (DSSC). The counter electrode was made of cobalt sulfide (CoS) nanoparticles synthesized via surfactant-assisted preparation of a metal organic framework, ZIF-67, with controllable particle sizes (50 to 320?nm) and subsequent oxidation and sulfide conversion. In contrast to conventional Pt counter electrodes, the synthesized CoS nanoparticles exhibited higher external surface areas and roughness factors, as evidenced by X-ray diffraction (XRD), scanning electron microscopy (SEM) element mapping, and electrochemical analysis. Incident photon-to-current conversion efficiency (IPCE) results showed an increase in the open circuit voltage (VOC) and a decrease in the short-circuit photocurrent density (Jsc) for CoS-based DSSCs compared to Pt-based DSSCs, resulting in a similar power conversion efficiency. The CoS-based DSSC fabricated in the study show great potential for economically friendly production of Pt-free DSSCs. PMID:25382139

Hsu, Shao-Hui; Li, Chun-Ting; Chien, Heng-Ta; Salunkhe, Rahul R.; Suzuki, Norihiro; Yamauchi, Yusuke; Ho, Kuo-Chuan; Wu, Kevin C.-W.

2014-01-01

220

Mesoporous Bi2S3 nanorods with graphene-assistance as low-cost counter-electrode materials in dye-sensitized solar cells.  

PubMed

In this work, we report the synthesis of mesoporous Bi2S3 nanorods under hydrothermal conditions without additives, and investigated their catalytic activities as the CE in DSCs by I-V curves and tested conversion efficiency. To further improve their power conversion efficiency, we added different amounts of reduced graphene by simple physical mixing. With the addition of 9 wt% reduced graphene (rGO), the short-circuit current density, open-circuit voltage and fill factor were Jsc = 15.33 mA cm(-2), Voc = 0.74 V and FF = 0.609. More importantly, the conversion efficiency reached 6.91%, which is slightly inferior to the commercial Pt counter electrode (7.44%). Compared to the conventional Pt counter electrodes of solar cells, this new material has the advantages of low-cost, facile synthesis and high efficiency with graphene assistance. To the best of our knowledge, this Bi2S3 + 9 wt% rGO system has the best performance ever recorded in all Bi2S3-based CEs in the DSCs system. PMID:25341187

Guo, Sheng-Qi; Jing, Tian-Zeng; Zhang, Xiao; Yang, Xiao-Bing; Yuan, Zhi-Hao; Hu, Fang-Zhong

2014-11-01

221

Platinum-Free Counter Electrode Comprised of Metal-Organic-Framework (MOF)-Derived Cobalt Sulfide Nanoparticles for Efficient Dye-Sensitized Solar Cells (DSSCs).  

PubMed

We fabricated a highly efficient (with a solar-to-electricity conversion efficiency (?) of 8.1%) Pt-free dye-sensitized solar cell (DSSC). The counter electrode was made of cobalt sulfide (CoS) nanoparticles synthesized via surfactant-assisted preparation of a metal organic framework, ZIF-67, with controllable particle sizes (50 to 320?nm) and subsequent oxidation and sulfide conversion. In contrast to conventional Pt counter electrodes, the synthesized CoS nanoparticles exhibited higher external surface areas and roughness factors, as evidenced by X-ray diffraction (XRD), scanning electron microscopy (SEM) element mapping, and electrochemical analysis. Incident photon-to-current conversion efficiency (IPCE) results showed an increase in the open circuit voltage (VOC) and a decrease in the short-circuit photocurrent density (Jsc) for CoS-based DSSCs compared to Pt-based DSSCs, resulting in a similar power conversion efficiency. The CoS-based DSSC fabricated in the study show great potential for economically friendly production of Pt-free DSSCs. PMID:25382139

Hsu, Shao-Hui; Li, Chun-Ting; Chien, Heng-Ta; Salunkhe, Rahul R; Suzuki, Norihiro; Yamauchi, Yusuke; Ho, Kuo-Chuan; Wu, Kevin C-W

2014-01-01

222

Graphene-NiO nanohybrid prepared by dry plasma reduction as a low-cost counter electrode material for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

NiO nanoparticles (NPs) were hybridized on the surface of reduced graphene oxide (RGO) by dry plasma reduction (DPR) at atmospheric pressure without any toxic chemicals and at a low temperature. NiO-NPs of 0.5-3 nm size, with a typical size of 1.5 nm, were uniformly hybridized on the surface of RGO. An XPS analysis and the Raman spectra also revealed the repair of some structural damage on the basal plane of the graphene. The material when applied to the counter electrode (CE) of dye-sensitized solar cells (DSCs) exhibited a power conversion efficiency of 7.42% (+/-0.10%), which is comparable to a conventional Pt-sputtered CE (8.18% (+/-0.08%)). This material outperformed CEs produced using NiO-NPs (1.53% (+/-0.15%)), GO (4.48% (+/-0.12%)) and RGO (5.18% (+/-0.11)) due to its high electrochemical catalytic activity and high conductivity. The charge transfer resistance for NiO-NP-RGO was as low as 1.93 ? cm2, while those of a NiO-NP-immobilized electrode and a GO-coated electrode were 44.39 ? cm2 and 12.19 ? cm2, respectively, due to a synergistic effect.NiO nanoparticles (NPs) were hybridized on the surface of reduced graphene oxide (RGO) by dry plasma reduction (DPR) at atmospheric pressure without any toxic chemicals and at a low temperature. NiO-NPs of 0.5-3 nm size, with a typical size of 1.5 nm, were uniformly hybridized on the surface of RGO. An XPS analysis and the Raman spectra also revealed the repair of some structural damage on the basal plane of the graphene. The material when applied to the counter electrode (CE) of dye-sensitized solar cells (DSCs) exhibited a power conversion efficiency of 7.42% (+/-0.10%), which is comparable to a conventional Pt-sputtered CE (8.18% (+/-0.08%)). This material outperformed CEs produced using NiO-NPs (1.53% (+/-0.15%)), GO (4.48% (+/-0.12%)) and RGO (5.18% (+/-0.11)) due to its high electrochemical catalytic activity and high conductivity. The charge transfer resistance for NiO-NP-RGO was as low as 1.93 ? cm2, while those of a NiO-NP-immobilized electrode and a GO-coated electrode were 44.39 ? cm2 and 12.19 ? cm2, respectively, due to a synergistic effect. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr04871c

Dao, Van-Duong; Larina, Liudmila L.; Jung, Kwang-Deog; Lee, Joong-Kee; Choi, Ho-Suk

2013-12-01

223

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

224

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 310-5 mA/cm2 at a reverse bias of 6 V. Therefore, our study paves the way for indium-free, see-through OLED displays.

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

2008-08-01

225

Large-scale fabrication of a continuous gold network for use as a transparent conductive electrode in photo-electronic devices  

NASA Astrophysics Data System (ADS)

Large-scale periodic gold network electrodes were fabricated using the developed and versatile nanosphere lithography technique. The fabrication processes, structural characterizations and network formation mechanism were described in detail. An enhanced optical transmission peak was observed from the transmission spectrum, which could be assigned to the extraordinary transmission mediated commonly by (a) localized surface plasmon resonance (LSPR) and (b) surface plasmon polaritons. The effects of film thickness, sphere diameter (periodicity) and reactive ion etching time on their optical and electrical properties were also investigated. By controlling these three independent variables, we could tune the SPR peak position and their light transmission distributions flexibly. Our large-scale continuous gold network can serve as a transparent conductive electrode, while possessing the role of a surface plasmonic resonance component can make it very attractive for potential photo-electric device applications in a range from plasmon-enhanced broadband photovoltaics to SPR-based chemo- and biosensors.

Cheng, Ke; Cui, Zhonggang; Li, Qianqian; Wang, Shujie; Du, Zuliang

2012-10-01

226

Large-scale fabrication of a continuous gold network for use as a transparent conductive electrode in photo-electronic devices.  

PubMed

Large-scale periodic gold network electrodes were fabricated using the developed and versatile nanosphere lithography technique. The fabrication processes, structural characterizations and network formation mechanism were described in detail. An enhanced optical transmission peak was observed from the transmission spectrum, which could be assigned to the extraordinary transmission mediated commonly by (a) localized surface plasmon resonance (LSPR) and (b) surface plasmon polaritons. The effects of film thickness, sphere diameter (periodicity) and reactive ion etching time on their optical and electrical properties were also investigated. By controlling these three independent variables, we could tune the SPR peak position and their light transmission distributions flexibly. Our large-scale continuous gold network can serve as a transparent conductive electrode, while possessing the role of a surface plasmonic resonance component can make it very attractive for potential photo-electric device applications in a range from plasmon-enhanced broadband photovoltaics to SPR-based chemo- and biosensors. PMID:23037191

Cheng, Ke; Cui, Zhonggang; Li, Qianqian; Wang, Shujie; Du, Zuliang

2012-10-26

227

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

PubMed

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 TiO(2) 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. TiO(2) 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 TiO(2). Electron microscopy analysis and impedance measurements showed that a thin continuous TiO(2) layer is formed at the interface as a result of the local melting of TiO(2) 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 TiO(2) paste revealed an efficiency improvement from eta = 3.3% to 5.4%, and an increase from 8.2% to 11.2% was achieved with the TiO(2) electrodes made from a commercial paste. PMID:20671364

Kim, Jinsoo; Kim, Jonghyun; Lee, Myeongkyu

2010-08-27

228

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

NASA Astrophysics Data System (ADS)

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

229

Oxygen-assisted low-pressure chemical vapor deposition for the low-temperature direct growth of graphitic nanofibers on fluorine-doped tin oxide glass as a counter electrode for dye-sensitized solar cell  

NASA Astrophysics Data System (ADS)

In this paper, we report an oxygen-assisted low-pressure chemical vapor deposition (LPCVD) method for the direct growth of graphitic nanofibers (GNFs) on a fluorine-doped tin oxide (FTO) glass substrate at a low temperature (550 C). By adding moderate concentrations of oxygen in a gas mixture of argon, ethylene, and hydrogen during LPCVD, an extremely dense GNF forest can be obtained on a nickel-coated FTO glass substrate. Though this process, the graphitic nanofibers are grown homogenously on a large area of FTO glass. It was observed that oxygen-assisted LPCVD leads to the direct growth of high-quality GNFs as a counter electrode for dye-sensitized solar cells (DSSCs). In combination with an N719 dye-sensitized TiO2 working electrode and an iodine-based electrolyte, the DSSC with a GNF counter electrode showed a power conversion efficiency of 5.51% under AM 1.5 (100 mW cm?2) illumination, which approached that of the DSSC with a Pt counter electrode (5.44%). The results demonstrated that our directly grown GNFs could be promising candidates for counter electrodes to achieve high performance in DSSCs.

Chen, Chih-Sheng; Hsieh, Chien-Kuo

2014-11-01

230

Photoresist-free patterning by mechanical abrasion of water-soluble lift-off resists and bare substrates: toward green fabrication of transparent electrodes.  

PubMed

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. PMID:24358321

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

2013-01-01

231

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

232

Enhanced charge transportation in a polypyrrole counter electrode via incorporation of reduced graphene oxide sheets for dye-sensitized solar cells.  

PubMed

In this work, reduced graphene oxide (RGO) sheets are successfully introduced into the conductive polypyrrole (PPy) matrix as conductive channels and co-catalyst, through simple incorporation of graphene oxide (GO) into PPy and subsequent in situ reduction from GO/PPy to RGO/PPy composite film. The RGO/PPy film is fabricated as a counter electrode for dye-sensitized solar cells, and it exhibits excellent catalytic performance for reduction of triiodide. For this reason, the incorporated RGO sheets significantly improve short-circuit photocurrent density from 14.27 to 15.81 mA cm(-2) and power conversion efficiency from 7.11% to 8.14%, which is comparable with that for the cell based on a Pt cathode. PMID:23171993

Gong, Feng; Xu, Xin; Zhou, Gang; Wang, Zhong-Sheng

2013-01-14

233

Synthesis of Honeycomb-like Mesoporous Pyrite FeS2 Microspheres as Efficient Counter Electrode in Quantum Dots Sensitized Solar Cells.  

PubMed

Honeycomb-like mesoporous pyrite FeS2 microspheres, with diameters of 500-800 nm and pore sizes of 25-30 nm, are synthesized by a simple solvothermal approach. The mesoporous FeS2 microspheres are demonstrated to be an outstanding counter electrode (CE) material in quantum dot sensitized solar cells (QDSSCs) for electrocatalyzing polysulfide electrolyte regeneration. The cell using mesoporous FeS2 microspheres as CE shows 86.6% enhancement in power conversion efficiency (PCE) than the cell using traditional noble Pt CE. Furthermore, it also shows 11.4% enhancement in PCE than the cell using solid FeS2 microspheres as CE, due to the mesoporous structure facilitating better contact with polysulfide electrolyte and fast diffusion of redox couple species in electrolyte. PMID:24986216

Xu, Jun; Xue, Hongtao; Yang, Xia; Wei, Huaixin; Li, Wenyue; Li, Zhangpeng; Zhang, Wenjun; Lee, Chun-Sing

2014-11-01

234

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

235

Two-step electrochemical synthesis of polypyrrole/reduced graphene oxide composites as efficient pt-free counter electrode for plastic dye-sensitized solar cells.  

PubMed

Polypyrrole/reduced graphene oxide (PPy/RGO) composites on the rigid and plastic conducting substrates were fabricated via a facile two-step electrochemical process at low temperature. The polypyrrole/graphene oxide (PPy/GO) composites were first prepared on the substrate with electrochemical polymerization method, and the PPy/RGO composites were subsequently obtained by electrochemically reducing the PPy/GO. The resultant PPy/GO and PPy/RGO composites were porous, in contrast to the dense and flat pristine PPy films. The cyclic voltammetry measurement revealed that resultant composites exhibited a superior catalytic performance for triiodide reduction in the order of PPy/RGO > PPy/GO > PPy. The catalytic activity of PPy/RGO was comparable to that of Pt counter electrode (CE). Under the optimal conditions, an energy conversion efficiency of 6.45% was obtained for a rigid PPy/RGO-based dye-sensitized solar cell, which is 90% of that for a thermally deposited Pt-based device (7.14%). A plastic counter electrode was fabricated by depositing PPy/RGO composites on the plastic ITO/PEN substrate, and then an all-plastic device was assembled and exhibited an energy conversion efficiency of 4.25%, comparable to that of the counterpart using a sputtered-Pt CE (4.83%) on a plastic substrate. These results demonstrated that electrochemical synthesis is a facile low-temperature method to fabricate high-performance RGO/polymer composite-based CEs for plastic DSCs. PMID:25162375

Liu, Wantao; Fang, Yanyan; Xu, Peng; Lin, Yuan; Yin, Xiong; Tang, Guangshi; He, Meng

2014-09-24

236

Study of H2SO4 concentration on properties of H2SO4 doped polyaniline counter electrodes for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Nanostructured polyaniline (PANI) counter electrodes (CEs) with different doping levels have been fabricated using in-situ electrochemical polymerization under different doping H2SO4 concentration for applications in dye-sensitized solar cells (DSSCs). The effects of the H2SO4 concentration on properties of the obtained PANI CEs, such as morphology, degree of polymerization, doping level of the SO42- counter anions, oxidization state, and electrochemical activity for I3- reduction, are thoroughly investigated using different techniques, such as scanning electron microscope (SEM), ultraviolet-visible light spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). When using D149 dye-sensitized nanocrystalline TiO2 photoanode, DSSC based on PANI CE polymerized with 0.35 M H2SO4 shows the best photovoltaic performance with a solar-to-energy conversion efficiency up to 5.57%, which is competitive to that of Pt CE-based solar cells (6.00%). This is because PANI CE polymerized under such conditions exhibits high catalytic activity for I-/I3- redox reaction because of the large surface area, high degree of polymerization/oriented structure, high doping level, and high emeraldine base oxidization state. Thus, our results can help to prepare the PANI CEs with a better DSSC performance and, more important, to better understand the operation mechanism of PANI CEs.

Wang, Shasha; Lu, Shan; Li, Xuemin; Zhang, Xuehua; He, Shengtai; He, Tao

2013-11-01

237

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 200C 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 85C) 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 25C) 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 500C 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

238

Synergistically enhanced stability of highly flexible silver nanowire/carbon nanotube hybrid transparent electrodes by plasmonic welding.  

PubMed

Here, we report highly transparent and flexible AgNW/SWCNT hybrid networks on PET substrates combined with plasmonic welding for securing ultrahigh stability in mechanical and electrical properties under severe bending. Plasmonic welding produces local heating and welding at the junction of AgNWs and leads strong adhesion between AgNW and SWCNT as well as between hybrid structure and substrate. The initial sheet resistance of plasmon treated AgNW/SWCNT hybrid film was 26 ? sq(-1), with >90% optical transmittance over the wavelength range 400-2700 nm. Following 200 cycles of convex/concave bending with a bending radius of 5 mm, the sheet resistance changed from 26 to 29 ? sq(-1). This hybrid structure combined with the plasmonic welding process provided excellent stability, low resistance, and high transparency, and is suitable for highly flexible electronics applications, including touch panels, solar cells, and OLEDs. PMID:24972024

Lee, Jongsoo; Woo, Ju Yeon; Kim, Ju Tae; Lee, Byung Yang; Han, Chang-Soo

2014-07-23

239

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

240

In situ observation of structure and electrical property changes of a Ga-doped ZnO/graphene flexible transparent electrode during deformation  

NASA Astrophysics Data System (ADS)

Ga-doped ZnO (GZO)/graphene multilayer film was fabricated on the polyethylene terephthalate substrate at room temperature. The obtained GZO/graphene multilayer showed a transparence of 75% at 550 nm and a sheet resistance of 721 ?/sq. Our findings indicate that the graphene intermediate layer plays a critical role in improving the conductivities of GZO. Under a tensile strain, the sheet resistance of the GZO electrode without graphene exhibited a sharp increase owing to the plenty of cracks formed in the GZO layer. In contrast, the GZO/graphene multilayer displayed a relatively stable and low resistance during the tensile deformation due to the excellent mechanical and electrical stabilities of the graphene.

Zhang, L. Q.; Gao, Z. F.; Tu, Z. Q.; Liu, C.; Qi, Y.; Yang, F.; Yang, W.; Jiang, D. Q.; Guo, Y. P.; Ye, Z. Z.; Lu, J. G.; Hou, X. Y.; Li, Y. F.; Cui, L. S.

2014-06-01

241

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. PMID:22222148

2012-01-01

242

An electrochromic window based on poly( N-methyl-10,10-dimethylphenazasiline) and ITO electrodes  

Microsoft Academic Search

The performance of an electrochromic window with a poly (N-methyl-10,10-dimethylphenazasiline) electrochromic electrode and indium-tin oxide optically passive counter-electrode has been tested both in liquid and solid-state configurations. Preliminary results, based on transmission spectra and electrical and optical responses to repeated potential switches between transparent and dark states, suggest the viability of this device in smart window technology.

M. Mastragostino; A. Zanelli; G. Casalbore-Miceli; A. Geri

1995-01-01

243

A transparent conductive adhesive laminate electrode for high-efficiency organic-inorganic lead halide perovskite solar cells.  

PubMed

A self-adhesive laminate solar-cell electrode is presented based on a metal grid embedded in a polymer film (x-y conduction) and set in contact with the active layer using a pressure-sensitive adhesive containing a very low quantity (1.8%) of organic conductor, which self-organizes to provide z conduction to the grid. This ITO-free material performs in an identical fashion to evaporated gold in high-efficiency perovskite solar cells. PMID:25257313

Bryant, Daniel; Greenwood, Peter; Troughton, Joel; Wijdekop, Maarten; Carnie, Mathew; Davies, Matthew; Wojciechowski, Konrad; Snaith, Henry J; Watson, Trystan; Worsley, David

2014-11-01

244

Electrochemical and structural properties of SnO[sub 2] and Sb:SnO[sub 2] transparent electrodes with mixed electronically conductive and ion-storage characteristics  

SciTech Connect

Doped (F, Sb, Mo) tin(IV) oxide (SnO[sub 2]) films are used as transparent-conductive electrodes in electrochromic devices (ECD), and low-emitting (i.e, heat reflecting) coatings for advanced glazing in solar applications. Thin SnO[sub 2] and Sb-doped SnO[sub 2] films have been prepared from aqueous colloidal solutions containing SnCl[sub 4][center dot]5H[sub 2]O and SbCl[sub 3] precursors by the dip-coating technique. The films are characterized as small grains (40 to 70 [angstrom]) and exhibit the ability to uptake reversibly Li[sup +] and H[sup +] ions from solutions of LiClO[sub 4] (0.1M) in acetonitrile (AN) or water, LiOH (0.1M) and HCIO[sub 4] (0.001 to 0.01 M). It was found that Sb-doped (7 a/o Sb) SnO[sub 2] films thicker than 100 nm exhibit about three times greater (de) inserted charges as compared to the undoped films. With regard to the amount of (de) inserted charge (up to 8 mC/cm[sup 2]), Sb-doped SnO[sub 2] films are suitable for mixed electronically conductive, ion-storage electrodes in electrochromic devices.

Orel, B.; Lavrencic-Stangar, U. (National Inst. of Chemistry, Ljubljana (Slovenia)); Kalcher, K. (Karl-Franzens Univ., Graz (Austria). Inst. of Analytical Chemistry)

1994-09-01

245

Fabrication of wide-bandgap transparent electrodes by using conductive filaments: performance breakthrough in vertical-type GaN LED.  

PubMed

For realizing next-generation solid-state lighting devices, performance breakthroughs must be accomplished for nitride-based light-emitting diodes (LEDs). Highly transparent conductive electrodes (TCEs) may be key to achieving this goal, as they provide uniform current injection and distribution across a large device area, eventually increasing the light output power. However, the trade-off between electrical conductivity and optical transmittance of LEDs must be addressed. Herein, we introduce a novel strategy based on TCEs fabricated using wide-bandgap (WB) materials such as SiNx, incorporated beneath the n-type electrode of vertical-type LEDs, and show the feasibility of this strategy. We employ a novel electrical breakdown (EBD) technique to form conductive filaments (or current paths) between a TCE and n-GaN (GaN: gallium nitride). By employing the EBD process, we obtain both ohmic behavior for SiNx TCE/n-GaN and a current spreading effect across n-GaN. These results demonstrate the tremendous potential of WB-TCEs for use in high-performance optoelectronic devices. PMID:25059757

Kim, Su Jin; Kim, Hee-Dong; Kim, Kyeong Heon; Shin, Hee Woong; Han, Il Ki; Kim, Tae Geun

2014-01-01

246

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

247

Iron pyrite thin film counter electrodes for dye-sensitized solar cells: high efficiency for iodine and cobalt redox electrolyte cells.  

PubMed

Iron pyrite has been the material of interest in the solar community due to its optical properties and abundance. However, the progress is marred due to the lack of control on the surface and intrinsic chemistry of pyrite. In this report, we show iron pyrite as an efficient counter electrode (CE) material alternative to the conventional Pt and poly(3,4-ethylenedioxythiophene (PEDOT) CEs in dye-sensitized solar cells (DSSCs). Pyrite film CEs prepared by spray pyrolysis are utilized in I3(-)/I(-) and Co(III)/Co(II) electrolyte-mediated DSSCs. From cyclic voltammetry and impedance spectroscopy studies, the catalytic activity is found to be comparable with that of Pt and PEDOT in I3(-)/I(-) and Co(III)/Co(II) electrolyte, respectively. With the I3(-)/I(-) electrolyte, photoconversion efficiency is found to be 8.0% for the pyrite CE and 7.5% for Pt, whereas with Co(III)/Co(II) redox DSSCs, efficiency is found to be the same for both pyrite and PEDOT (6.3%). The excellent performance of the pyrite CE in both the systems makes it a distinctive choice among the various CE materials studied. PMID:25241831

Shukla, Sudhanshu; Loc, Nguyen Huu; Boix, Pablo P; Koh, Teck Ming; Prabhakar, Rajiv Ramanujam; Mulmudi, Hemant K; Zhang, Jun; Chen, Shi; Ng, Chin Fan; Huan, Cheng Hon Alfred; Mathews, Nripan; Sritharan, Thirumany; Xiong, Qihua

2014-10-28

248

In situ synthesis of binded, thick and porous carbon nanoparticle dye sensitized solar cell counter electrode with nickel gel as catalyst source  

NASA Astrophysics Data System (ADS)

A TiO2-embedded NiCl2 gel is prepared and used as growth catalyst to in situ synthesize binded, thick and porous carbon nanoparticles (CNPs) on Ti foil substrate with a simple flame synthesis method for dye sensitized solar cell (DSSC) counter electrode (CE) applications. The viscous gel catalyst can hold sufficient NiCl2 coated on substrate to make CNP layer thick. The embedded TiO2 can effectively separate the abundant NiCl2 components to active the Ni catalyst for CNP growth and then make CNP layer become porous. In addition, the TiO2 components can bind the porous CNP products to make them conductive. With an optimized TiO2 fraction, the CE shows high catalytic ability and electrical conductivity. By applying this CNP CE for DSSC, a photovoltaic conversion efficiency of 6.6% is achieved, which exceeds 6.5% of a reference cell using costly platinum as CE. Furthermore, the CNP structure is demonstrated beneficial to carrier transport by a mass transfer model. This easy and effective preparation method may have a potential application in general nanomaterial preparation.

Zeng, Wei; Fang, Guojia; Han, Tianyang; Li, Borui; Liu, Nishuang; Zhao, Dongshan; Liu, Zhiqiang; Wang, Dianyuan; Zhao, Xingzhong; Zou, Dechun

2014-01-01

249

Spray deposited copper zinc tin sulphide (Cu2ZnSnS4) film as a counter electrode in dye sensitized solar cells.  

PubMed

Stoichiometric thin films of Cu2ZnSnS4 (CZTS) were deposited by the spray technique on a FTO coated glass substrate, with post-annealing in a H2S environment to improve the film properties. CZTS films were used as a counter electrode (CE) in Dye-Sensitized Solar Cells (DSCs) with N719 dye and an iodine electrolyte. The DSC of 0.25 cm(2) area using a CE of CZTS film annealed in a H2S environment under AM 1.5G illumination (100 mW cm(-2)) exhibited a short circuit current density (JSC) = 18.63 mA cm(-2), an open circuit voltage (VOC) = 0.65 V and a fill factor (FF) = 0.53, resulting in an overall power conversion efficiency (PCE) = 6.4%. While the DSC using as deposited CZTS film as a CE showed the PCE = 3.7% with JSC = 13.38 mA cm(-2), VOC = 0.57 V and FF = 0.48. Thus, the spray deposited CZTS films can play an important role as a CE in the large area DSC fabrication. PMID:25286339

Swami, Sanjay Kumar; Chaturvedi, Neha; Kumar, Anuj; Chander, Nikhil; Dutta, Viresh; Kumar, D Kishore; Ivaturi, A; Senthilarasu, S; Upadhyaya, Hari M

2014-11-21

250

Water-soluble polyelectrolyte-grafted multiwalled carbon nanotube thin films for efficient counter electrode of dye-sensitized solar cells.  

PubMed

Water-soluble, polyelectrolyte-grafted multiwalled carbon nanotubes (MWCNTs), MWCNT-g-PSSNa, were synthesized using a "grafting to" route. MWCNT-g-PSSNa thin films fabricated by an electrostatic spray (e-spray) technique were used as the counter electrode (CE) for dye-sensitized solar cells (DSSCs). The e-sprayed MWCNT-g-PSSNa thin-film-based CEs (MWCNT-CE) were uniform over a large area, and the well-exfoliated MWCNTs formed highly interconnected network structures. The electrochemical catalytic activity of the MWCNT-CE at different thicknesses was investigated. The MWCNT-g-PSSNa thin film showed high efficiency as a CE in DSSCs. The power conversion efficiency (PCE) of the DSSCs using the MWCNT-g-PSSNa thin-film-based CE (DSSC-MWCNT) was >6% at a CE film thickness of approximately 0.3 microm. The optimum PCE was >7% at a film thickness of approximately 1 microm, which is 20-50 times thinner than conventional carbon-based CE. The charge transfer resistance at the MWCNT-CE/electrolyte interface was 1.52 Omega cm(2) at a MWCNT-CE thickness of 0.31 microm, which is lower than that of a Pt-CE/electrolyte interface, 1.78 Omega cm(2). This highlights the potential for the low-cost CE fabrication of DSSCs using a facile deposition technique from an environmentally "friendly" solution at low temperatures. PMID:20509667

Han, Jinkyu; Kim, Hyunju; Kim, Dong Young; Jo, Seong Mu; Jang, Sung-Yeon

2010-06-22

251

Performances of some low-cost counter electrode materials in CdS and CdSe quantum dot-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Different counter electrode (CE) materials based on carbon and Cu2S were prepared for the application in CdS and CdSe quantum dot-sensitized solar cells (QDSSCs). The CEs were prepared using low-cost and facile methods. Platinum was used as the reference CE material to compare the performances of the other materials. While carbon-based materials produced the best solar cell performance in CdS QDSSCs, platinum and Cu2S were superior in CdSe QDSSCs. Different CE materials have different performance in the two types of QDSSCs employed due to the different type of sensitizers and composition of polysulfide electrolytes used. The poor performance of QDSSCs with some CE materials is largely due to the lower photocurrent density and open-circuit voltage. The electrochemical impedance spectroscopy performed on the cells showed that the poor-performing QDSSCs had higher charge-transfer resistances and CPE values at their CE/electrolyte interfaces.

Jun, Hieng Kiat; Careem, Mohamed Abdul; Arof, Abdul Kariem

2014-02-01

252

Performances of some low-cost counter electrode materials in CdS and CdSe quantum dot-sensitized solar cells  

PubMed Central

Different counter electrode (CE) materials based on carbon and Cu2S were prepared for the application in CdS and CdSe quantum dot-sensitized solar cells (QDSSCs). The CEs were prepared using low-cost and facile methods. Platinum was used as the reference CE material to compare the performances of the other materials. While carbon-based materials produced the best solar cell performance in CdS QDSSCs, platinum and Cu2S were superior in CdSe QDSSCs. Different CE materials have different performance in the two types of QDSSCs employed due to the different type of sensitizers and composition of polysulfide electrolytes used. The poor performance of QDSSCs with some CE materials is largely due to the lower photocurrent density and open-circuit voltage. The electrochemical impedance spectroscopy performed on the cells showed that the poor-performing QDSSCs had higher charge-transfer resistances and CPE values at their CE/electrolyte interfaces. PMID:24512605

2014-01-01

253

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.

254

Alternative methods to fabricate and evaluate copper zinc tin sulfide based absorber layers on transparent conducting electrodes  

NASA Astrophysics Data System (ADS)

This study is focused on fabrication and characterization of Cu 2ZnSnS4 (CZTS) films on transparent conducting substrate. CZTS films were synthesized using solution based methods. A specially designed sequential and single stage electrochemical method as well as spin coating method was used to grow layers of precursors. Deposition of constituent metallic layers was carried out on SnO2/F (Fluorinated tin oxide or FTO) coated glass substrates. The electrodeposited/spin coated layers were annealed in a sulfur environment to obtain CZTS. Structural, morphological and optical characterization experiments were performed using several techniques including x-ray diffraction, Raman and UV-visible spectroscopy, scanning electron microscopy, and atomic force microscopy. All characterization experiments indicated the films are single phase with a measured direct band gap of 1.5 eV. Photocurrent response of CZTS film grown on FTO substrate was measured using alternating front illumination and rear illumination in a Eu 3+/Eu2+ solution environment. The photoelectrochemical response exhibited during rear illumination is comparable to that obtained for front illumination. The promising photocurrent data for CZTS films suggest these films have potential application in a variety of photovoltaic devices. A comparative study revealed that photoelectrochemical response exhibited by the films grown on molybdenum substrate is greater than that obtained for film grown on FTO substrate. A modified form of the Gartner model to explain J-V characteristics for CZTS-electrolyte solution has been proposed. Fundamental information such as energy band gap-temperature relationship and temperature dependent study of Raman 'A' mode for CZTS thin films were also investigated in this research.

Sarswat, Prashant Kumar

255

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

256

Transparent lithium-ion batteries  

PubMed Central

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 10Wh/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

2011-01-01

257

Engineering the Interfaces of ITO@Cu2S Nanowire Arrays toward Efficient and Stable Counter Electrodes for Quantum-Dot-Sensitized Solar Cells.  

PubMed

Among the issues that restrict the power conversion efficiency (PCE) of quantum-dot-sensitized solar cells (QDSSCs), insufficient catalytic activity and stability of counter electrodes (CEs) are critical but challenging ones. The state-of-the-art Cu/Cu2S CEs still suffer from mechanical instability and uncertainty due to the reaction of copper and electrolyte. Herein, ITO@Cu2S core-shell nanowire arrays were developed to fabricate CEs for QDSSCs, which have no such issues in Cu/Cu2S CEs. These nanowire arrays exhibited small charge transfer resistance and sheet resistance, and provided more active catalytic sites and easy accessibility for electrolyte due to the three-dimensional structure upon use as CEs. More interestingly, it was found that the interface of ITO/Cu2S significantly affected the performance of ITO@Cu2S nanowire array CEs. By varying synthetic methods, a series of ITO@Cu2S nanowire arrays were prepared to investigate the influence of ITO/Cu2S interface on their performance. The results showed that ITO@Cu2S nanowire array CEs with a continuous Cu2S nanocrystal shell fabricated via an improved cation exchange route exhibited excellent and thickness-dependent performance. The PCE of corresponding QDSSCs increased by 11.6 and 16.5% compared to that with the discrete Cu2S nanocrystal and the classic Cu/Cu2S CE, respectively, indicating its promising potential as a new type of CE for QDSSCs. PMID:25137502

Jiang, Yan; Zhang, Xing; Ge, Qian-Qing; Yu, Bin-Bin; Zou, Yu-Gang; Jiang, Wen-Jie; Hu, Jin-Song; Song, Wei-Guo; Wan, Li-Jun

2014-09-10

258

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

Rodrguez-Moreno, Jorge; Navarrete-Astorga, Elena; Dalchiele, Enrique A; Schrebler, Ricardo; Ramos-Barrado, Jos R; Martn, Francisco

2014-05-30

259

Transparency International  

NSDL National Science Digital Library

With headquarters in Berlin, Transparency International (TI) is an international non-governmental organization dedicated to combating corruption in its many guises across the world. As their website notes, TI âfocuses on prevention and reforming systemsâ. With a well-designed and rather elegant homepage, visitors will find much to admire here. The top of the homepage provides access to their âIn Focusâ feature, which draws attention to some of TIâs more recent work, such as the Global Corruption Report for 2006. Below this feature, visitors will find links to recent news stories dealing with corruption, such as the recent Kenyan government scandal and anti-corruption initiatives in West Africa. Visitors can also utilize the âCorruption: Learn About itâ area, as it contains FAQs on corruption, and a number of indices, such as the global corruption barometer as well as a number of regional surveys. For pragmatic material, one need to look no further than their âHow to Fight Corruptionâ section, which contains an anti-corruption handbook and a set of business principles for countering bribery.

260

Facile Water-based Spray Pyrolysis of Earth-Abundant Cu2FeSnS4 Thin Films as an Efficient Counter Electrode in Dye-Sensitized Solar Cells.  

PubMed

A novel approach to produce earth-abundant Cu2FeSnS4 (CFTS) thin film using spray pyrolysis of nontoxic aqueous precursors followed by sulfurization is reported. The CFTS phase formation was confirmed by both Raman spectroscopy and X-ray diffraction techniques. Hall measurements of these films reveal p-type conductivity with good charge carrier density and mobilities appropriate for solar harvesting devices. To the best of our knowledge, this is the first report on the electrical properties of solution-processed Cu2FeSnS4 thin films estimated using Hall measurements. Dye-sensitized solar cells (DSSC) fabricated with CFTS thin film as a photocathode in iodine/iodide electrolyte exhibit good power conversion efficiency, 8.03%, indicating that CFTS would be a promising cheaper alternative to replace Pt as a counter electrode in DSSCs. PMID:25255739

Prabhakar, Rajiv Ramanujam; Huu Loc, Nguyen; Kumar, Mulmudi Hemant; Boix, Pablo P; Juan, Sun; John, Rohit Abraham; Batabyal, Sudip K; Wong, Lydia Helena

2014-10-22

261

Effect of doping concentration on the properties of aluminium doped zinc oxide thin films prepared by spray pyrolysis for transparent electrode applications  

Microsoft Academic Search

Zinc oxide possesses many interesting properties, such as modifiable conductivity, wide band gap, high excitonic binding energy, piezo-electric polarisation and cathodoluminiscence. In this study transparent conducting aluminium doped zinc oxide (ZnO:Al) thin films were deposited on float glass substrates by tailor made spray pyrolysis with adaptation for measuring the actual temperature of the substrate surface during deposition. The films were

C. M. Muiva; T. S. Sathiaraj; K. Maabong

2011-01-01

262

Conductive and transparent multilayer films for low-temperature TiO2/Ag/SiO2 electrodes by E-beam evaporation with IAD  

PubMed Central

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 700nm 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

2014-01-01

263

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 700nm 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

264

Vacuum-Free, Maskless Patterning of Ni Electrodes by Laser Reductive Sintering of NiO Nanoparticle Ink and Its Application to Transparent Conductors.  

PubMed

We introduce a method for direct patterning of Ni electrodes through selective laser direct writing (LDW) of NiO nanoparticle (NP) ink. High-resolution Ni patterns are generated from NiO NP thin films by a vacuum-free, lithography-free, and solution-processable route. In particular, a continuous wave laser is used for the LDW reductive sintering of the metal oxide under ambient conditions with the aid of reducing agents in the ink solvent. Thin (?40 nm) Ni electrodes of glossy metallic surfaces with smooth morphology and excellent edge definition can be fabricated. By applying this method, we demonstrate a high transmittance (>87%), electrically conducting panel for a touch screen panel application. The resistivity of the Ni electrode is less than an order of magnitude higher compared to that of the bulk Ni. Mechanical bending test, tape-pull test, and ultrasonic bath test confirm the robust adhesion of the electrodes on glass and polymer substrates. PMID:25130917

Lee, Daeho; Paeng, Dongwoo; Park, Hee K; Grigoropoulos, Costas P

2014-10-28

265

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

266

Effect of surface nanomorphology and interfacial galvanic coupling of PEDOT-titanium counter electrodes on the stability of dye-sensitized solar cell.  

PubMed

The present study demonstrates a novel approach by which titanium foils coated with electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT) in combination with sputtered platinum can be processed into a high-surface area cathodes for dye-sensitized solar cells (DSSCs). A detailed study has been performed to elucidate how surface nanomorphology and I(-)/I(3-) redox reaction behaviors underlying these photocathodes impact the DSSC performances. From the analysis of the relevant electrochemical parameters, an intrinsic correlation between the photovoltaic performances and the cathode surface area has been deduced for such a system and explained on the basis of relative contributions of the galvanic coupling properties of the nanomorphology PEDOT film and platinum. Depending on the type of photocathodes incorporated, it was observed that these PEDOT coated cathodes can exhibit higher stability over a given time range and photo-conversion efficiencies 12-40%, higher than that achievable in absence of the intermediate PEDOT coatings. It has been shown that DSSCs based on such metal-polymer hybrid photo-cathodes allow significant room for improvement in the catalytic performance at the electrode/electrolyte interface. PMID:22962746

Madhavan, Asha Anish; Kalluri, Sujith; Paravannoor, Anjali; Nagarajan, Sivakumar; Subramanian, Kavasseri R V; Nair, Shantikumar; Balakrishnan, Avinash

2012-08-01

267

Electrospun TiC/C nano-felt surface-decorated with Pt nanoparticles as highly efficient and cost-effective counter electrode for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Electrospun nano-felt consisting of overlaid TiC/C composite nanofibers was surface-decorated with Pt nanoparticles (Pt NPs) for use as highly efficient and cost-effective counter electrode (CE) in dye-sensitized solar cells (DSSCs). In the nanofibers, the self-generated TiC crystallites (~70 wt%) with sizes of ~20 nm were randomly embedded in carbon (~30 wt%). Upon surface-decoration, most Pt NPs were distributed on TiC crystallites, leading to substantial enhancement in the electrocatalytic activity/efficiency of Pt due to the strong interaction between Pt and TiC as well as the resulting synergetic effect on electrocatalysis. Electrochemical measurements indicated that the TiC/C-Pt CE exhibited low charge transfer resistance (Rct), large capacitance (C), and fast reaction rate towards the reduction of I3- ions, and the prototype DSSC exhibited a performance comparable to that with conventional Pt CE in terms of short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), and energy conversion efficiency (?).

Zhao, Yong; Thapa, Amit; Feng, Quan; Xi, Min; Qiao, Qiquan; Fong, Hao

2013-11-01

268

Silver nanowire-based transparent, flexible, and conductive thin film  

Microsoft Academic Search

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)

Cai-Hong Liu; Xun Yu

2011-01-01

269

Semitransparent inverted polymer solar cells employing a sol-gel-derived TiO2 electron-selective layer on FTO and MoO3/Ag/MoO3 transparent electrode.  

PubMed

We report a new semitransparent inverted polymer solar cell (PSC) with a structure of glass/FTO/nc-TiO2/P3HT:PCBM/MoO3/Ag/MoO3. Because high-temperature annealing which decreased the conductivity of indium tin oxide (ITO) must be handled in the process of preparation of nanocrystalline titanium oxide (nc-TiO2), we replace glass/ITO with a glass/fluorine-doped tin oxide (FTO) substrate to improve the device performance. The experimental results show that the replacing FTO substrate enhances light transmittance between 400 and 600 nm and does not change sheet resistance after annealing treatment. The dependence of device performances on resistivity, light transmittance, and thickness of the MoO3/Ag/MoO3 film was investigated. High power conversion efficiency (PCE) was achieved for FTO substrate inverted PSCs, which showed about 75% increase compared to our previously reported ITO substrate device at different thicknesses of the MoO3/Ag/MoO3 transparent electrode films illuminated from the FTO side (bottom side) and about 150% increase illuminated from the MoO3/Ag/MoO3 side (top side). PMID:25332693

Li, Fumin; Chen, Chong; Tan, Furui; Li, Chunxi; Yue, Gentian; Shen, Liang; Zhang, Weifeng

2014-01-01

270

Semitransparent inverted polymer solar cells employing a sol-gel-derived TiO2 electron-selective layer on FTO and MoO3/Ag/MoO3 transparent electrode  

PubMed Central

We report a new semitransparent inverted polymer solar cell (PSC) with a structure of glass/FTO/nc-TiO2/P3HT:PCBM/MoO3/Ag/MoO3. Because high-temperature annealing which decreased the conductivity of indium tin oxide (ITO) must be handled in the process of preparation of nanocrystalline titanium oxide (nc-TiO2), we replace glass/ITO with a glass/fluorine-doped tin oxide (FTO) substrate to improve the device performance. The experimental results show that the replacing FTO substrate enhances light transmittance between 400 and 600 nm and does not change sheet resistance after annealing treatment. The dependence of device performances on resistivity, light transmittance, and thickness of the MoO3/Ag/MoO3 film was investigated. High power conversion efficiency (PCE) was achieved for FTO substrate inverted PSCs, which showed about 75% increase compared to our previously reported ITO substrate device at different thicknesses of the MoO3/Ag/MoO3 transparent electrode films illuminated from the FTO side (bottom side) and about 150% increase illuminated from the MoO3/Ag/MoO3 side (top side). PMID:25332693

2014-01-01

271

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.

272

Transparent hearing  

Microsoft Academic Search

This paper describes what we call Transparent Hearing: the use of microphone equipped headphones for augmented audio. It provides a framework for experiments like real-time audio alteration, multi-modal sensory integration and collaborative listening experiences. We attach high-quality microphones to headphones and send the signal through a computer to these headphones. We have built headphones that stop the music if somebody

Florian Mueller; Matthew Karau

2002-01-01

273

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

274

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

275

Use of silica aerogels in Cherenkov counters  

Microsoft Academic Search

Silica aerogel is widely used as a radiator for Cherenkov detectors. It is a highly porous, low-density, and transparent substance\\u000a with refractive index n ranging between the values of n n ? 1.3 for condensed phases. The review is devoted to the consideration of various factors affecting the identification of\\u000a particles in Cherenkov counters: the chromatic aberration, the number of

Yu. N. Kharzheev

2008-01-01

276

Particle Countin' Geiger Counter  

NSDL National Science Digital Library

This simulation demonstrates the detection of radioactivity using a Geiger counter. The source of radiation and counter shielding can be selected. The radioactivity measurement is simulated with both a dial reading and audible clicks.

2004-07-12

277

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

278

Thin film solar cell with free tin on tin oxide transparent conductor  

Microsoft Academic Search

A solar cell is described which consists of: a transparent front face electrode comprising oxides of one or more metals, a layer of free metal on the front face electrode, the free metal layer comprising at least one of the one or more metals, the layer of free metal being substantially transparent to visible light, a thin film photovoltaic device

K. K. Mackamul; D. L. Morel; D. P. Tanner

1986-01-01

279

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. PMID:23105970

Jung, Hyun Young; Karimi, Majid B.; Hahm, Myung Gwan; Ajayan, Pulickel M.; Jung, Yung Joon

2012-01-01

280

Solution-Processed Poly(3,4-ethylenedioxythiophene) Thin Films as Transparent Conductors: Effect of p-Toluenesulfonic Acid in Dimethyl Sulfoxide.  

PubMed

Conductivity enhancement of thin transparent films based on poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) by a solution-processed route involving mixture of an organic acid and organic solvent is reported. The combined effect of p-toluenesulfonic acid and dimethyl sulfoxide on spin-coated films of PEDOT-PSS on glass substrates, prepared from its commercially available aqueous dispersion, was found to increase the conductivity of the PEDOT-PSS film to ?3500 Scm(-1) with a high transparency of at least 94%. Apart from conductivity and transparency measurements, the films were characterized by Raman, infrared, and X-ray photoelectron spectroscopy along with atomic force microscopy and secondary ion mass spectrometry. Combined results showed that the conductivity enhancement was due to doping, rearrangement of PEDOT particles owing to phase separation, and removal of PSS matrix throughout the depth of the film. The temperature dependence of the resistance for the treated films was found to be in accordance with one-dimensional variable range hopping, showing that treatment is effective in reducing energy barrier for interchain and interdomain charge hopping. Moreover, the treatment was found to be compatible with flexible poly(ethylene terephthalate) (PET) substrates as well. Apart from being potential candidates to replace inorganic transparent conducting oxide materials, the films exhibited stand-alone catalytic activity toward I(-)/I3(-) redox couple as well and successfully replaced platinum and fluorinated tin oxide as counter electrode in dye-sensitized solar cells. PMID:25230160

Mukherjee, Smita; Singh, Rekha; Gopinathan, Sreelekha; Murugan, Sengottaiyan; Gawali, Suhas; Saha, Biswajit; Biswas, Jayeeta; Lodha, Saurabh; Kumar, Anil

2014-10-22

281

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

282

The art of transparency  

PubMed Central

Artists throughout the ages have discovered a number of techniques to depict transparency. With only a few exceptions, these techniques follow closely the properties of physical transparency. The two best known properties are X-junctions and the luminance relations described by Metelli. X-junctions are seen where the contours of a transparent material cross contours of the surface behind; Metelli's constraints on the luminance relations between the direct and filtered portions of the surface specify a range of luminance values that are consistent with transparency. These principles have been used by artists since the time of ancient Egypt. However, artists also discovered that stimuli can be seen as transparent even when these physical constraints are not met. Ancient Greek artists, for example, were able to depict transparent materials in simple black-and-white line drawings. Artists also learned how to represent transparency in cases where neither X-junctions nor Metelli's constraints could apply: for example, where no portions of the objects behind the transparent material extend beyond it. Many painters convincingly portrayed transparency in these cases by depicting the effects the transparent medium would have on material or object properties. Here, we show how artists employed these and other techniques revealing their anticipation of current formalizations of perceived transparency, and we suggest new, as-yet-untested principles. PMID:23145252

Sayim, Bilge; Cavanagh, Patrick

2011-01-01

283

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

284

GASEOUS SCINTILLATION COUNTER  

Microsoft Academic Search

A gaseous excitation counter for detecting the presence amd measuring ; the energy of subatomic particles and electromagnetic radiation is described. ; The counter includes a gas-tight chamber filled with an elemental gas capable of ; producing ultra-violet excitation quanta when irradiated with subatomic particles ; and electromagnetic radiation. The gas has less than one in a thousand parts ;

C. Eggler; C. M. Huddleston

1959-01-01

285

Optical microcavities clad by transparent conductive oxides  

Microsoft Academic Search

Transparent conductive oxide (TCO) films are proposed as electrode materials for direct current injection optical microcavity devices. Four types of planar indium-tin-oxide (ITO) clad optical microcavities -1-D photonic crystal nanobeam, 2-D photonic crystal slab, 3-D photonic crystal and microdisk are designed and analyzed both by perturbation theory and 3D finite difference time domain (FDTD) analysis. The quality (Q) factors of

Ozlem Senlik; Lingling Tang; Pantana Tor-Ngern; Tomoyuki Yoshie

2011-01-01

286

Samus Counter Lifting Fixture  

SciTech Connect

A lifting fixture has been designed to handle the Samus counters. These counters are being removed from the D-zero area and will be transported off site for further use at another facility. This fixture is designed specifically for this particular application and will be transferred along with the counters. The future use of these counters may entail installation at a facility without access to a crane and therefore a lift fixture suitable for both crane and/or fork lift usage has been created The counters weigh approximately 3000 lbs. and have threaded rods extended through the counter at the top comers for lifting. When these counters were first handled/installed these rods were used in conjunction with appropriate slings and handled by crane. The rods are secured with nuts tightened against the face of the counter. The rod thread is M16 x 2({approx}.625-inch dia.) and extends 2-inch (on average) from the face of the counter. It is this cantilevered rod that the lift fixture engages with 'C' style plates at the four top comers. The strongback portion of the lift fixture is a steel rectangular tube 8-inch (vertical) x 4-inch x .25-inch wall, 130-inch long. 1.5-inch square bars are welded perpendicular to the long axis of the rectangular tube at the appropriate lift points and the 'C' plates are fastened to these bars with 3/4-10 high strength bolts -grade 8. Two short channel sections are positioned-welded-to the bottom of the rectangular tube on 40 feet centers, which are used as locators for fork lift tines. On the top are lifting eyes for sling/crane usage and are rated at 3500 lbs. safe working load each - vertical lift only.

Stredde, H.; /Fermilab

1998-05-27

287

Manufacturability of lab-on-chip devices : dimensional variation analysis of electrode foils using visual technology  

E-print Network

Electrodes are necessary components for measuring changes in electrical properties in many microfluidic devices. Daktari CD4 Cell Counter system utilizes an interdigitated electrode foil in order to measure the concentration ...

Namvari, Kasra

2011-01-01

288

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. PMID:21711602

2011-01-01

289

Transparent Conductors and Barrier Layers for Thin Film Solar Cells  

Microsoft Academic Search

This report describes the research undertaken to increase the efficiency of thin-film solar cells based on amorphous silicon in the so-called''superstrate structure'' (glass front surface\\/transparent electrically conductive oxide (TCO)\\/pin amorphous silicon\\/metal back electrode). The TCO layer must meet many requirements: high optical transparency in the wavelength region from about 350 to 900 nm, low electrical sheet resistance, stability during handling

R. G. Gordon; R. Broomhall-Dillard; X. Liu; D. Pang; J. Barton

2001-01-01

290

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

291

Transparent Layer Constancy  

Microsoft Academic Search

Perceived transparency was studied as a constancy problem. In the episcotister (E-) model of scission, luminances are partitioned into layer and background components; four luminances determine values of two layer parameters that specify constancy of a transparent layer on different backgrounds. The E-model was tested in an experiment in which 12 Ss matched 24 pairs of four-luminance patterns by adjusting

Walter Gerbino; Casimir I. F. H. J. Stultiens; Jim M. Troost; Charles M. M. de Weert

1990-01-01

292

Cross Polarizing Transparent Organics  

E-print Network

://upload.wikimedia.org/wikipedia/commons/f/f9/Sunglasses-1_retouch.png Slide 3: http://people.rit.edu/andpph/text-figures/polarization/polarizationCross Polarizing Transparent Organics Kenny Harvey Carleton College, Northfield MN Fleischer Group #12;Polarization #12;Advantage of Polarization Detect Residual Stresses in Transparent Plastics

Petta, Jason

293

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

294

Radiation effects on silver and zinc battery electrodes. II. July-October 1965  

Microsoft Academic Search

The study of the effects of radiation on silver and zinc electrodes was continued with specific attention being given to the silver electrode. Cadmium counter electrodes were used with the silver electrodes in the study pending the availability of suitable zinc electrodes. Material losses from irradiated silver electrodes of 3.0 g total weight averaged 60.2, 77.7, and 52.9 mg at

G. R. Argue; H. L. Recht; W. A. McCollum

1965-01-01

295

Deposition of TiO2 Passivation Layer by Plasma Enhanced Chemical Vapor Deposition between the Transparent Conducting Oxide and Mesoporous TiO2 Electrode in Dye Sensitized Solar Cells  

NASA Astrophysics Data System (ADS)

The characteristic of TiO2 passivation layers grown by plasma enhanced chemical vapor deposition as a function of its thickness on F-doped SnO2 (FTO) electrode was investigated. The thickness of TiO2 passivation layer was varied from 30 to 200 nm by controlling the deposition time. The electric resistance of the TiO2 layers was depended on the thickness, so the optimized thickness in enhancing the connection and reducing the recombination of electrons on the surface of FTO electrode was determined. The dye sensitized solar cells fabricated with 40 nm thick TiO2 passivation layer showed the maximum power conversion efficiency of 6.93%. It was due to the effective connection of mesoporous TiO2 and FTO and the prevention of electron recombination from the FTO to electrolyte. The reduced resistance, enlarged electron diffusion length measured by the electrochemical impedance spectroscopy, intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spectroscopy identified the connection and anti-recombination effect.

Lee, Su Young; Kim, Sang Ho

2012-10-01

296

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

297

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

298

Gas threshold Cerenkov counters  

NASA Technical Reports Server (NTRS)

The report describes two designs are reported of gas threshold Cerenkov counters for recording electrons of primary cosmic rays without recording protons. Also presented are design and technological measures which ensure maximum light collection of the Cerenkov radiation originating on the photocathode of the photomultiplier inside the radiator. The dependence of the reflection factor on the length of the light wave for different coatings is shown as well as for the throughput of the different optical materials employed. A range of methods for determining the efficiency of the counters during the recording of cosmic ray nucons and ways of increasing it further are given.

Logachev, V. I.; Sinitsyna, V. G.; Chukin, V. S.

1975-01-01

299

Semitransparent Organic Photovoltaic Cells with Laminated Top Electrode  

E-print Network

Semitransparent Organic Photovoltaic Cells with Laminated Top Electrode Jung-Yong Lee, Steve T demonstrate semitransparent small molecular weight organic photovoltaic cells using a laminated silver metal cathode due to differences in optical absorption. KEYWORDS Organic photovoltaics, transparent

Cui, Yi

300

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?, ebojka

301

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

302

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.

Kolar, Predrag; Miljkovi?, Budimir; ?urguz, Zoran

2012-05-01

303

Transparent Information Dissemination  

Microsoft Academic Search

This paper describes Transparent Replication through Invalidation and Prefetching (TRIP<\\/I>), a self tuning data replication middleware system that enables transparent replication of large-scale information dissemination services. The TRIP middleware is a key building block for constructing information dissemination<\\/I> services, a class of services where updates occur at an origin server and reads occur at a number of replicas; examples information

Amol Nayate; Michael Dahlin; Arun Iyengar

2004-01-01

304

Nano Res (2010) 3: 564573564 Uniform, Highly Conductive, and Patterned Transparent Films  

E-print Network

displays, solar cells, and light emitting diodes [1­3].Doped-metal oxides such as tin-doped indium oxideNano Res (2010) 3: 564­573564 Uniform, Highly Conductive, and Patterned Transparent Films alternatives to tin-doped indium oxide (ITO) films as transparent conductive electrodes. In this paper, we

Zhou, Chongwu

305

Origin of high photoconductive gain in fully transparent heterojunction nanocrystalline oxide image sensors and interconnects.  

PubMed

A technique for invisible image capture using a photosensor array based on transparent conducting oxide semiconductor thin-film transistors and transparent interconnection technologies is presented. A transparent conducting layer is employed for the sensor electrodes as well as interconnection in the array, providing about 80% transmittance at visible-light wavelengths. The phototransistor is a Hf-In-Zn-O/In-Zn-O heterostructure yielding a high quantum-efficiency in the visible range. PMID:25219518

Jeon, Sanghun; Song, Ihun; Lee, Sungsik; Ryu, Byungki; Ahn, Seung-Eon; Lee, Eunha; Kim, Young; Nathan, Arokia; Robertson, John; Chung, U-In

2014-11-01

306

High-Speed Counters and Fluid Forward-Backward Counters.  

National Technical Information Service (NTIS)

The pure fluid forward-backward counter has a first input for receiving fluid signals which cause the counter to count up and a second input for receiving fluid signals which cause the counter to count down. A series of fluid pulse converters are provided...

R. W. Warren

1965-01-01

307

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

308

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.; Flgge, H.; Schmale, S.; Blow, T.; Meyer, J.; Johannes, H.-H.; Riedl, T.; Kowalsky, W.

2009-08-01

309

Development of a Transparent Self Cleaning Dust Shield for Solar Panels  

Microsoft Academic Search

Development of a transparent electrodynamic shield to protect panels from dust deposition is described. The shield contains a clear panel with embed- ded parallel electrodes connected to a single-phase AC supply for producing an electromagnetic wave. The electromagnetic field produced by the electrodes on the surface of the panel repels dust particles that have already deposited on the panel surface,

R. A. Sims; A. S. Biris; J. D. Wilson; C. U. Yurteri; M. K. Mazumder; C. I. Calle; C. R. Buhler

310

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

311

Solution processed zinc oxide nanopyramid/silver nanowire transparent network films with highly tunable light scattering properties.  

PubMed

Metal nanowire transparent networks are promising replacements to indium tin oxide (ITO) transparent electrodes for optoelectronic devices. While the transparency and sheet resistance are key metrics for transparent electrode performance, independent control of the film light scattering properties is important to developing multifunctional electrodes for improved photovoltaic absorption. Here we show that controlled incorporation of ZnO nanopyramids into a metal nanowire network film affords independent, highly tunable control of the scattering properties (haze) with minimal effects on the transparency and sheet resistance. Varying the zinc oxide/silver nanostructure ratios prior to spray deposition results in sheet resistances, transmission (600 nm), and haze (600 nm) of 6-30 ? ?(-1), 68-86%, and 34-66%, respectively. Incorporation of zinc oxide nanopyramid scattering agents into the conducting nanowire mesh has a negligible effect on mesh connectivity, providing a straightforward method of controlling electrode scattering properties. The decoupling of the film scattering power and electrical characteristics makes these films promising candidates for highly scattering transparent electrodes in optoelectronic devices and can be generalized to other metal nanowire films as well as carbon nanotube transparent electrodes. PMID:23575765

Mehra, Saahil; Christoforo, Mark G; Peumans, Peter; Salleo, Alberto

2013-05-21

312

Transparent Animals Snke Johnsen  

E-print Network

(upper left corner) was rumored to be an inspi- ration for the monster in the movie Alien; it is actually stand out. Phronima (upper left corner) was rumored to be an inspi- ration for the monster in the movie--half-indi- vidual, half-colony. The best-known example is the Portuguese man-of-war. Most are transparent, but some

Johnsen, Sönke

313

Product Information Transparent  

E-print Network

Product Information Solar FEATURES · Transparent · Cures to flexible elastomer · Constant cure rate · No solvents or cure byproducts · Repairable · Good dielectric properties · Deep section cure · UL 94 V1, V0 · UL RTI 130°C (266°F) COMPOSITION · Two-part silicone elastomer supplied as flowable liquid

Yoo, S. J. Ben

314

Raising and Transparency.  

ERIC Educational Resources Information Center

An account of the phenomena that transformational syntax handled by means of "raising" is formulated in the context of cognitive grammar. Raising is analyzed as a special case of the metonymy that relational expressions exhibit in regard to their choice of overtly coded arguments. The transparency of these constructions is explained. (83

Langacker, Ronald W.

1995-01-01

315

The most transparent research  

Microsoft Academic Search

Biomedicine would be a breeze if organisms were transparent. With the ability to see through tissues, scientists could spot the development of tumors more easily in study animals. And biologists could study exactly how an animal's organs develop by observing them as they grow. In effect, the secrets of the body would be out there for everyone to see.The thought

Melinda Wenner

2009-01-01

316

Ion-selective electrodes in medicinal drug determination  

NASA Astrophysics Data System (ADS)

Data published in the past 10 years on the use of ion-selective electrodes in direct potentiometry and potentiometric titration for the determination of organic medicinal drugs are analysed. In the vast majority of cases, ion-sensitive membranes contain associates of drug cations or anions with appropriate counter-ions. The theoretical approaches to optimisation of the characteristics of ion-selective electrodes are discussed. The mechanism of electrode response generation for neutral and charged carriers of organic ions is considered.

Kharitonov, Sergei V.

2007-04-01

317

Features of the microstrip proportional counter technology (invited)  

SciTech Connect

The microstrip proportional counter (MSPC) is a new approach in gas-filled detector technology. In contrast with the classical multiwire proportional counter (MWPC) detectors, the electrodes of the MSPC are deposited by photolithographic techniques onto a rigid substrate. The technique offers many important advantages: An optimal energy resolution; The possibility of matching the electrode structure to the expected spatial resolution, i.e., smaller electrode distances than are possible for MWPCs; A much faster signal development than for the MWPC because of the small distance (few 100 {mu}m) between the anode and cathode strips which allows the positive ion cloud created in the avalanche to be collected rapidly with reduced space charge effects and increased counting-rate capability; A rigid electrode structure which is not deformed under the action of an electric field; A relatively simple fabrication technique which allows the rapid replacement of damaged electrode structures. The applications of the MSPC within the fields of x-ray astronomy, neutron diffraction, high energy physics, and synchrotron radiation will be discussed.

Budtz-Jorgensen, C. (Danish Space Research Institute, G1. Lundtoftevej 7, DK-2800 Lyngby (Denmark))

1992-01-01

318

Progress towards cavity induced transparency  

E-print Network

Inspired by electromagnetically induced transparency (EIT), cavity induced transparency (CIT) uses a cavity rather than a laser to couple a ground state with the excited state of a three-level system. In this thesis, I ...

Li, Tracy (Tracy Yang)

2010-01-01

319

Progress in Perturbative Color Transparency  

E-print Network

A brief overview of the status of color transparency experiments is presented. We report on the first complete calculations of color transparency within a perturbative QCD framework. We also comment on the underlying factorization method and assumptions. Detailed calculations show that the slope of the transparency ratio with $Q^2$, and the effective attenuation cross sections extracted from color transparency experiments depend on the $x$ distribuition of wave functions.

John P. Ralston; Pankaj Jain; Bijoy Kundu; Jim Samuelsson

2000-08-18

320

Flexible electrochromic films based on CVD-graphene electrodes  

NASA Astrophysics Data System (ADS)

Graphene synthesized via chemical vapor deposition is a notable candidate for flexible large-area transparent electrodes due to its great physical properties and its 2D activated surface area. Electrochromic devices in optical displays, smart windows, etc are suitable applications for graphene when used as a transparent conductive electrode. In this study, various-layer graphene was synthesized via chemical vapor deposition, and inorganic WOx was deposited on the layers, which have advantageous columnar structures and W6+ and W4+ oxidation states. The characteristics of graphene and WOx were verified using optical transmittance, Raman spectroscopy, x-ray photoelectron spectroscopy and scanning electron microscopy. The optimum transparent conductive electrode condition for controlling graphene layers was investigated based on the optical density and cyclic voltammetry. Electrochromic devices were fabricated using a three-layer graphene electrode, which had the best optical density. The graphene in the flexible electrochromic device demonstrated a potential for replacing ITO in flexible electronics.

Choi, Dong Soo; Han, Seung Ho; Kim, Hyeongkeun; Kang, So Hee; Kim, Yena; Yang, Cheol-Min; Kim, Tae Young; Yoon, Dae Ho; Yang, Woo Seok

2014-09-01

321

Automatic method to manufacture 2D Multiwire Proportional Counter frames  

NASA Astrophysics Data System (ADS)

In this paper, a complete solution to manufacture anodes and cathodes for a Multiwire Proportional Counter (MWPC) is described. The solution consists of a semiautomatic winding machine and a soldering method by radiation. This method allows manufacturing one frame (electrode) in 3 h with a minimum human intervention. The machine can work with several types of frames and a great accuracy in the position and the stress of the wires can be achieved.

Martnez, J. C.; Ramos-Lerate, I.; Fernndez, F.; Beltrn, D.; Bordas, J.

2007-04-01

322

Cl-Doped ZnO Nanowires with Metallic Conductivity and Their Application for High-Performance Photoelectrochemical Electrodes  

E-print Network

conductor, photoelectrochemical cell 1. INTRODUCTION Doping semiconductor nanowires (NWs) with impurityO NWs also see their application in electrodes for flexible transparent electronics where convoluted Zn and abundance. The success of Al-doped ZnO (AZO) films as transparent window electrodes in thin film solar cells

Wang, Xudong

323

Transparent conducting oxide nanotubes.  

PubMed

Thin film or porous membranes made of hollow, transparent, conducting oxide (TCO) nanotubes, with high chemical stability, functionalized surfaces and large surface areas, can provide an excellent platform for a wide variety of nanostructured photovoltaic, photodetector, photoelectrochemical and photocatalytic devices. While large-bandgap oxide semiconductors offer transparency for incident light (below their nominal bandgap), their low carrier concentration and poor conductivity makes them unsuitable for charge conduction. Moreover, materials with high conductivity have nominally low bandgaps and hence poor light transmittance. Here, we demonstrate thin films and membranes made from TiO2 nanotubes heavily-doped with shallow Niobium (Nb) donors (up to 10%, without phase segregation), using a modified electrochemical anodization process, to fabricate transparent conducting hollow nanotubes. Temperature dependent current-voltage characteristics revealed that TiO2 TCO nanotubes, doped with 10% Nb, show metal-like behavior with resistivity decreasing from 6.5נ10(-4) ?cm at T=300 K (compared to 6.5נ10(-1) ?cm for nominally undoped nanotubes) to 2.2נ10(-4) ?cm at T=20 K. Optical properties, studied by reflectance measurements, showed light transmittance up to 90%, within wavelength range 400 nm-1000 nm. Nb doping also improves the field emission properties of TCO nanotubes demonstrating an order of magnitude increase in field-emitter current, compared to undoped samples. PMID:25180635

Alivov, Yahya; Singh, Vivek; Ding, Yuchen; Nagpal, Prashant

2014-09-26

324

Transparent conducting oxide nanotubes  

NASA Astrophysics Data System (ADS)

Thin film or porous membranes made of hollow, transparent, conducting oxide (TCO) nanotubes, with high chemical stability, functionalized surfaces and large surface areas, can provide an excellent platform for a wide variety of nanostructured photovoltaic, photodetector, photoelectrochemical and photocatalytic devices. While large-bandgap oxide semiconductors offer transparency for incident light (below their nominal bandgap), their low carrier concentration and poor conductivity makes them unsuitable for charge conduction. Moreover, materials with high conductivity have nominally low bandgaps and hence poor light transmittance. Here, we demonstrate thin films and membranes made from TiO2 nanotubes heavily-doped with shallow Niobium (Nb) donors (up to 10%, without phase segregation), using a modified electrochemical anodization process, to fabricate transparent conducting hollow nanotubes. Temperature dependent current-voltage characteristics revealed that TiO2 TCO nanotubes, doped with 10% Nb, show metal-like behavior with resistivity decreasing from 6.5 10-4 ?cm at T = 300 K (compared to 6.5 10-1 ?cm for nominally undoped nanotubes) to 2.2 10-4 ?cm at T = 20 K. Optical properties, studied by reflectance measurements, showed light transmittance up to 90%, within wavelength range 400 nm-1000 nm. Nb doping also improves the field emission properties of TCO nanotubes demonstrating an order of magnitude increase in field-emitter current, compared to undoped samples.

Alivov, Yahya; Singh, Vivek; Ding, Yuchen; Nagpal, Prashant

2014-09-01

325

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.; Krger, M.; Grrn, P.; Johannes, H.-H.; Riedl, T.; Lang, E.; Becker, D.; Dobbertin, T.; Kowalsky, W.

2007-09-01

326

Counter-Learning under Oppression  

ERIC Educational Resources Information Center

This qualitative study utilized the method of narrative analysis to explore the counter-learning process of an oppressed Kurdish woman from Turkey. Critical constructivism was utilized to analyze counter-learning; Frankfurt School-based Marcusian critical theory was used to analyze the sociopolitical context and its impact on the oppressed. Key

Kucukaydin, Ilhan

2010-01-01

327

Multi-layer electrode for high contrast electrochromic devices  

DOEpatents

An electrochromic device includes a first substrate spaced from a second substrate. A first transparent conductive electrode is formed over at least a portion of the first substrate. A polymeric anode is formed over at least a portion of the first conductive electrode. A second transparent conductive electrode is formed over at least a portion of the second substrate. In one aspect of the invention, a multi-layer polymeric cathode is formed over at least a portion of the second conductive electrode. In one non-limiting embodiment, the multi-layer cathode includes a first cathodically coloring polymer formed over at least a portion of the second conductive electrode and a second cathodically coloring polymer formed over at least a portion of the first cathodically coloring polymer. An ionic liquid is positioned between the anode and the cathode.

Schwendeman, Irina G. (Wexford, PA); Finley, James J. (Pittsburgh, PA); Polcyn, Adam D. (Pittsburgh, PA); Boykin, Cheri M. (Wexford, PA)

2011-11-01

328

Photoelectrochemical oxidation of water at transparent ferric oxide film electrodes.  

PubMed

The fabrication of thin-film Fe(2)O(3) photoanodes from the spray pyrolysis of Fe(III)-containing solutions is reported along with their structural characterization and application to the photoelectrolysis of water. These films combine good performance, measured in terms of photocurrent density, with excellent mechanical stability. A full investigation into the effects that modifications of the spray-pyrolysis method, such as the addition of dopants or structure-directing agents and changes in precursor species or carrier solvent, have on the performance of the photoanodes has been realized. The largest photocurrents were obtained from photoanodes prepared from ferric chloride precursor solutions, simultaneously doped with Ti(4+) (5%) and Al(3+) (1%). Doping with Zn(2+) also shows promise, cathodically shifting the onset potential by approximately 0.22 V. PMID:16852715

Jorand Sartoretti, Chantal; Alexander, Bruce D; Solarska, Renata; Rutkowska, Iwona A; Augustynski, Jan; Cerny, Radovan

2005-07-21

329

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.

330

Acne treatments (over-the-counter) Acupuncture  

E-print Network

treatments Ambulance and emergency health services Anesthesia (for non-cosmetic purposes) Antacid (over-the-counter antacid Over-the-counter antibiotic ointment Over-the-counter aspirin or other pain reliever Over

Bordenstein, Seth

331

EDM electrodes  

Microsoft Academic Search

A precision molded electrical discharge machining electrode is made by shaping a preform from granules of carbon and granules of a refractory material selected from the group consisting of tungsten, molybdenum, carbides thereof, and stoichiometric and hyperstoichiometric carbides of the other elements of the groups IVB, VB, and VIB of the Periodic Table of the Elements, the carbon and refractory

Th. E. Haskett; J. J. Schmitt

1984-01-01

332

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

333

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 vanderWaals 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

334

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

335

Experimental measure mass diffusion transparency  

NASA Astrophysics Data System (ADS)

Based on the concept of electromagnetic wave transparency in electromagnetic material, we proposed the concept of mass diffusion transparency. The mass diffusion transparency means that the trajectory of diffusion matter is not perturbed by neutral inclusion. We formulated different diffusion coefficient concrete by mixing cement, sand and glue, and fabricated the neutral inclusion. According to the mass diffusion transparent conditions, we obtained the size parameters and material parameters of the neutral inclusion. The simulation and experiment results show that the diffusion fluxes are parallel and equal outside the neutral inclusion, the iso-concentration lines are parallel outside the neutral inclusion.

Zeng, Lunwu; Song, Runxia; Zhao, Yanyan; Zhao, Zhigang

2014-05-01

336

APEX heavy-ion counters  

SciTech Connect

A large solid-angle array of low-pressure multi-wire proportional counters (LPMWPC) forms part of the APEX apparatus. Eight three-element trapezoidal counters provide 360{degrees} coverage in {phi} and 20{degrees} - 70{degrees} coverage in {phi}. Angle information is obtained from a transmission-line delay cathode ({phi}) and from the segmentation ({phi}). Time-of-flight information is obtained from the anode signals. These quantities are used to extract the center-of-mass scattering angle, reaction Q value, and masses of the scattered heavy ions. Design and performance of the counters will be discussed.

Mercer, D.J.

1993-10-01

337

Electromagnetically induced transparency in molecular systems and spectroscopic applications  

NASA Astrophysics Data System (ADS)

This work is devoted to the demonstration of electromagnetically induced transparency (EIT) in various types of open three-level molecular systems by application of optical-optical double resonance (OODR) spectroscopy. In particular, EIT has been investigated via fluorescence detection in two inhomogeneously broadened ?-type molecular systems: sodium and lithium dimer vapors. We have experimentally demonstrated the strong dependence of EIT upon the coupling field strength and presented a density matrix analysis to quantitatively account for the observed transparency. A complete study of EIT in a molecular V-type system (Na2) has been performed, for the first time, for both co- and counter-propagating beam geometries. In the latter case we have shown that EIT can be physically observed in open systems even for residual Doppler linewidths greater than the induced Autler-Townes (AT) splitting. Our findings have been complemented by theoretical studies that trace the presence of EIT at the density matrix level. Numerical simulations have been carried out indicating that, in a Doppler broadened environment and for two counter-propagating laser fields of modest Rabi frequencies, it is the openness of the V-type system that is accountable for rendering the medium transparent. These theoretical predictions agree well with the experimental results. Lastly, we have discovered through experiments that, in a cascade molecular system, the wavelength ratio of the applied laser fields can dramatically affect the AT splitting of the upper level. Our data has revealed that, for beams in a counter-propagating geometry with relatively small Rabi frequencies, the lineshape of the upper level fluorescence signal shows AT splitting only when the frequency of the coupling field is larger than that of the probe field. In contrast, observation of the fluorescence of the intermediate level appear to be almost unaffected by the laser frequency ratio.

Lazoudis, Angelos

338

Electrode Architecture  

Microsoft Academic Search

Retinal prosthesis presents a unique design challenge: how to form an electrical stimulation interface to a curved surface?\\u000a The challenge is primarily the lack of fabrication methods to pattern conductive material onto a spherical or curved surface.\\u000a The proximity of the electrodes to the retina is important because increased distance requires increased stimulation charge\\u000a and reduces acuity. Even flexible substrates,

Lee J. Johnson; Dean A. Scribner

339

Two-Color-Counter Toss  

NSDL National Science Digital Library

In this probability lesson plan students explore the concept of probability and learn to use the language of probability to describe outcomes. Students conduct an experiment with a two color counter, making prediction ahead of time, collecting data as the experiment is conducted, and then reporting their results. A similar experiment is then conducted with two two-color counters. A student recording sheet and a worksheet on probability statements are included in PDF format.

2011-01-01

340

[Data transparency - an ethical imperative? Approaching the issues].  

PubMed

Several studies show that the findings of clinical trials are often not published in full, resulting in a biased presentation of results (publication bias). First, this paper discusses the ethical arguments in favour of complete transparency of biomedical research data. There are relevant deontological (like obligations towards study participants and research sponsors) and consequentialist (harm for patients and misallocation of scarce resources) ethical reasons for the full publication of all trial results, which cannot be overridden by counter arguments like freedom of research, data protection or the individual interests of researchers and manufacturers. The article therefore discusses (1) which strategies are appropriate to guarantee data transparency and (2) who bears responsibility for the implementation of these strategies. Finally, open questions and the need for further action will be discussed. PMID:21530911

Marckmann, Georg; Strech, Daniel

2011-01-01

341

Transparent conducting coatings on glass tubes  

NASA Astrophysics Data System (ADS)

The conventional dip coating techinques, as it is used for flat surfaces, cannot be applied to deposit homogeneous coatings in optical quality inside tubes. The resulting coatings exhibit large variations in thickness and roughness over the length of the tube and show a morphology with a network of cracks. The main reason for these problems seem to be a delayed and restricted solvent evaporation due to the impediment of a laminar flow and the progressive saturation of the atmosphere in the tube. A modified dip coating technique was therefore developed to allow forced flow conditions inside the tubes by an additional exhausting tube. By means of this modification transparent conducting coatings of sol-gel SnO2:Sb (antimony-doped tin oxide - ATO) could be deposited on both sides of borosilicate glass tubes (300 mm, inner diamters down to 11 mm) with excellent thickness uniformity and low roughness (Ra~1nm). After a heat treatment at temperatures up to 500C, the prepared ATO coatings are mechanically stable and highly transparent (>85% transmission) with a sheet resistance down to 10 k?. The coatings can be used as electrodes for electronic devices and electrical heaters or to give antistatic properties to the substrate.

Puetz, Joerg; Chalvet, F. N.; Aegerter, Michel A.

2002-10-01

342

Fiscal Transparency and Economic Growth  

Microsoft Academic Search

Following several corporate accounting scandals many opted for greater corporate transparency whereas people almost blindly trusted state authorities and their released information especially on fiscal data. This attitude changed in the aftermath of several crisis in emerging market economies during the second half of the 1990s, which led the IMF to push for greater transparency of countries' fiscal positions. This

Michael Teig

343

TRANSPARENCY IN TRANSLATING FROM ARABIC  

Microsoft Academic Search

In current discourse on translation, and particularly from the perspectives of literary and cultural studies, the term transparency has acquired wide currency, denoting in most, but not all, cases attempts to conceal the translator's intervention from the reader of the target text. In this context the term transparency is used with a view to reappraising the role of the translator

Myriam Salama-Carr

2005-01-01

344

Correlation Effect on Stereo Transparency  

Microsoft Academic Search

AbstractStereo transparency is one of the important phenomena,for the computational study of binocular stere- opsis, because this perception raises a fundamental issue of how binocular disparities are represented in the brain. We investigate the perceptual property of stereo transparency with a specific stereogram generated by overlapping two identical dot patterns in different depths. This stereogram has potential matches leading to

Osamu Watanabe

345

Effect of geometric lattice design on optical/electrical properties of transparent silver grid for organic solar cells.  

PubMed

Silver (Ag) grid transparent electrode is one of the most promising transparent conducting electrodes (TCEs) to replace conventional indium tin oxide (ITO). We systematically investigate an effect of geometric lattice modifications on optical and electrical properties of Ag grid electrode. The reference Ag grid with 5 ?m width and 100 ?m pitch (duty of 0.05) prepared by conventional photo-lithography and lift-off processes shows the sheet resistance of 13.27 ?/sq, transmittance of 81.1%, and resultant figure of merit (FOM) of 129.05. Three different modified Ag grid electrodes with stripe added-mesh (SAM), triangle-added mesh (TAM), and diagonal-added mesh (DAM) are suggested to improve optical and electrical properties. Although all three of SAM, TAM, and DAM Ag grid electrodes exhibit the lower transmittance values of about 72 - 77%, they showed much decreased sheet resistance of 6 - 8 ?/sq. As a result, all of the lattice-modified Ag grid electrodes display significant improvement of FOM and the highest value of 171.14 is obtained from DAM Ag grid, which is comparable to that of conventional ITO electrode (175.46). Also, the feasibility of DAM Ag gird electrode for use in organic solar cell is confirmed by finite difference time domain (FDTD) simulations. Unlike a conventional ITO electrode, DAM Ag grid electrode can induce light scattering and trapping due to the diffuse transmission that compensates for the loss in optical transparency, resulting in comparable light absorption in the photo active layer of poly(3-hexylthiophene) (P3HT): [6,6]-phenyl-C61-butyric acid methyl ester (PC60BM). P3HT:PC60BM based OSCs with the DAM Ag grid electrode were fabricated, which also showed the potential for ITO-free transparent electrode. PMID:25401837

Lim, Ju Won; Lee, Young Tack; Pandey, Rina; Yoo, Tae-Hee; Sang, Byoung-In; Ju, Byeong-Kwon; Hwang, Do Kyung; Choi, Won Kook

2014-11-01

346

Long and Fast Up\\/Down Counters  

Microsoft Academic Search

This paper presents recent advances in the design of constant-time up\\/down counters in the general context of fast counter design. An overview of existing techniques for the design of long and fast counters reveals several methods closely related to the design of fast adders, as well as some techniques that are only valid for counter design. The main idea behind

Mircea R. Stan; Alexandre F. Tenca; Milos D. Ercegovac

1998-01-01

347

Large Collecting Area Sealed Proportional Counter  

Microsoft Academic Search

A large collecting area proportional counter for soft x-ray spectroscopy is described. The counter is a sealed instrument designed for inclusion in a rocket borne instrumentation package. The counter has an 82 cm2 collecting area and is sensitive from 1 to 8 . The energy spread of the counter with an 55Fe source is 34%.

C. Stuart Bowyer

1965-01-01

348

Nanostructured solid oxide fuel cell electrodes  

NASA Astrophysics Data System (ADS)

The ability of Solid Oxide Fuel Cells (SOFC) to directly and efficiently convert the chemical energy in hydrocarbon fuels to electricity places the technology in a unique and exciting position to play a significant role in the clean energy revolution. In order to make SOFC technology cost competitive with existing technologies, the operating temperatures have been decreased to the range where costly ceramic components may be substituted with inexpensive metal components within the cell and stack design. However, a number of issues have arisen due to this decrease in temperature: decreased electrolyte ionic conductivity, cathode reaction rate limitations, and a decrease in anode contaminant tolerance. While the decrease in electrolyte ionic conductivities has been countered by decreasing the electrolyte thickness, the electrode limitations have remained a more difficult problem. Nanostructuring SOFC electrodes addresses the major electrode issues. The infiltration method used in this dissertation to produce nanostructure SOFC electrodes creates a connected network of nanoparticles; since the method allows for the incorporation of the nanoparticles after electrode backbone formation, previously incompatible advanced electrocatalysts can be infiltrated providing electronic conductivity and electrocatalysis within well-formed electrolyte backbones. Furthermore, the method is used to significantly enhance the conventional electrode design by adding secondary electrocatalysts. Performance enhancement and improved anode contamination tolerance are demonstrated in each of the electrodes. Additionally, cell processing and the infiltration method developed in conjunction with this dissertation are reviewed.

Sholklapper, Tal Zvi

349

Nanostructured Solid Oxide Fuel Cell Electrodes  

SciTech Connect

The ability of Solid Oxide Fuel Cells (SOFC) to directly and efficiently convert the chemical energy in hydrocarbon fuels to electricity places the technology in a unique and exciting position to play a significant role in the clean energy revolution. In order to make SOFC technology cost competitive with existing technologies, the operating temperatures have been decreased to the range where costly ceramic components may be substituted with inexpensive metal components within the cell and stack design. However, a number of issues have arisen due to this decrease in temperature: decreased electrolyte ionic conductivity, cathode reaction rate limitations, and a decrease in anode contaminant tolerance. While the decrease in electrolyte ionic conductivities has been countered by decreasing the electrolyte thickness, the electrode limitations have remained a more difficult problem. Nanostructuring SOFC electrodes addresses the major electrode issues. The infiltration method used in this dissertation to produce nanostructure SOFC electrodes creates a connected network of nanoparticles; since the method allows for the incorporation of the nanoparticles after electrode backbone formation, previously incompatible advanced electrocatalysts can be infiltrated providing electronic conductivity and electrocatalysis within well-formed electrolyte backbones. Furthermore, the method is used to significantly enhance the conventional electrode design by adding secondary electrocatalysts. Performance enhancement and improved anode contamination tolerance are demonstrated in each of the electrodes. Additionally, cell processing and the infiltration method developed in conjunction with this dissertation are reviewed.

Sholklapper, Tal Zvi

2007-12-15

350

Size Analysis in the Sub-sieve Range by Electronic Counter  

Microsoft Academic Search

THE electronic apparatus for the rapid measurement of particle content and size distribution, known as the Coulter counter1, is finding increasing application in many fields. A known volume of an extremely dilute suspension of particles in a conducting fluid flows through a standard interchangeable aperture having an immersed electrode on either side. The particles traverse the aperture substantially one at

C. C. Harris; A. JOWETT

1965-01-01

351

ENGINEERED ELECTRODES AND ELECTRODE-ORGANIC INTERFACES FOR HIGH-EFFICIENCY ORGANIC PHOTOVOLTAICS  

SciTech Connect

Organic photovoltaic (OPV) cells offer the ultimate promise of low cost, readily manufacturable, and durable solar power. While recent advances have led to cells with impressive performance levels, OPV cells have yet to break the double-digit efficiency barrier. Further gains in efficiency and durability, to that competitive with high-performance inorganic photovoltaics will require breakthroughs in transparent electrode and interfacial materials science and engineering. This project involved an integrated basic research effort carried out by an experienced and highly collaborative interdisciplinary team to address in unconventional ways, critical electrode-interfacial issues underlying OPV performance--controlling band offsets between transparent electrodes and organics, addressing current loss/leakage problems at interfaces, enhancing adhesion, interfacial stability, and device durability while minimizing cost. It synergistically combined materials and interfacial reagent synthesis, nanostructural and photovoltaic characterization, and high level quantum theory. The research foci were: 1) understanding of/development of superior transparent electrode materials and materials morphologies--i.e., better matched electronically and chemically to organic active layers, 2) understanding-based development of inorganic interfacial current-collecting/charge-blocking layers, and 3) understanding-based development of self-assembled adhesion/current-collecting/charge-blocking/cross-linking layers for high-efficiency OPV interfaces. Pursing the goal of developing the fundamental scientific understanding needed to design, fabricate, prototype and ultimately test high-efficiency OPV cells incorporating these new concepts, we achieved a record power conversion efficiency of 5.2% for an organic bulk-heterjunction solar cell.

Tobin J. Marks; R.P.H. Chang; Tom Mason; Ken Poeppelmeier; Arthur J. Freeman

2008-11-13

352

Transparent volume imaging  

NASA Astrophysics Data System (ADS)

Transparent Volume Imaging began with the stereo xray in 1895 and ended for most investigators when radiation safety concerns eliminated the second view. Today, similiar images can be generated by the computer without safety hazards providing improved perception and new means of image quantification. A volumetric workstation is under development based on an operational prototype. The workstation consists of multiple symbolic and numeric processors, binocular stereo color display generator with large image memory and liquid crystal shutter, voice input and output, a 3D pointer that uses projection lenses so that structures in 3 space can be touched directly, 3D hard copy using vectograph and lenticular printing, and presentation facilities using stereo 35mm slide and stereo video tape projection. Volumetric software includes a volume window manager, Mayo Clinic's Analyze program and our Digital Stereo Microscope (DSM) algorithms. The DSM uses stereo xray-like projections, rapidly oscillating motion and focal depth cues such that detail can be studied in the spatial context of the entire set of data. Focal depth cues are generated with a lens and apeture algorithm that generates a plane of sharp focus, and multiple stereo pairs each with a different plane of sharp focus are generated and stored in the large memory for interactive selection using a physical or symbolic depth selector. More recent work is studying non-linear focussing. Psychophysical studies are underway to understand how people perce ive images on a volumetric display and how accurately 3 dimensional structures can be quantitated from these displays.

Wixson, Steve E.

1990-07-01

353

Synchronized Current Oscillations of Formic Acid Electro-oxidation in a Microchip-based Dual-Electrode Flow Cell  

PubMed Central

We investigate the oscillatory electro-oxidation of formic acid on platinum in a microchip-based dual-electrode cell with microfluidic flow control. The main dynamical features of current oscillations on single Pt electrode that had been observed in macro-cells are reproduced in the microfabricated electrochemical cell. In dual-electrode configuration nearly in-phase synchronized current oscillations occur when the reference/counter electrodes are placed far away from the microelectrodes. The synchronization disappears with close reference/counter electrode placements. We show that the cause for synchronization is weak albeit important, bidirectional electrical coupling between the electrodes; therefore the unidirectional mass transfer interactions are negligible. The experimental design enables the investigation of the dynamical behavior in micro-electrode arrays with well-defined control of flow of the electrolyte in a manner where the size and spacing of the electrodes can be easily varied. PMID:20160883

Kiss, Istvan Z.; Munjal, Neil; Martin, R. Scott

2009-01-01

354

Transparent Polycrystalline Historical Developments and  

E-print Network

;Motivation · Historical perspective of solid-state laser development · Transition from pulsed · New EO and active media #12;Historical Perspective Historically, the first lasers were crystalsTransparent Polycrystalline Materials: Historical Developments and Next Generation Applications

Van Stryland, Eric

355

Development Gateway: Public Sector Transparency  

NSDL National Science Digital Library

This particular site casts an eye on the question of transparency in governmental transactions through interviews with leaders from a broad range of sectors, along with allowing space for individual feedback. The "Points of View" section is a good place to start, as it includes commentary from government officials from Bolivia, Guatemala, and Tanzania about the question of public sector transparency. Other sections on the site address such thorny questions as "What tools help sustain public sector transparency?" and "What practices promote public-private partnerships?" Those visual learners coming to visit the site may appreciate the gallery of charts that offer indicators of levels of governance and transparency for more than 209 countries.

356

Post-CMOS electrode formation and isolation for on-chip temperature-controlled  

E-print Network

-based biomimetic and bio- electronic interfaces on metal electrodes [1] generate an opportunity to form integrated electrochemical sensors that can simultaneously measure multiple analytes for a wide range of molecular analysis isolated and incorporating a resistive heating and sensing element, a gold counter electrode, and an Ag

Mason, Andrew

357

Modiolus-Hugging Intracochlear Electrode Array with Shape Memory Alloy  

PubMed Central

In the cochlear implant system, the distance between spiral ganglia and the electrodes within the volume of the scala tympani cavity significantly affects the efficiency of the electrical stimulation in terms of the threshold current level and spatial selectivity. Because the spiral ganglia are situated inside the modiolus, the central axis of the cochlea, it is desirable that the electrode array hugs the modiolus to minimize the distance between the electrodes and the ganglia. In the present study, we propose a shape-memory-alloy-(SMA-) embedded intracochlear electrode which gives a straight electrode a curved modiolus-hugging shape using the restoration force of the SMA as triggered by resistive heating after insertion into the cochlea. An eight-channel ball-type electrode array is fabricated with an embedded titanium-nickel SMA backbone wire. It is demonstrated that the electrode array changes its shape in a transparent plastic human cochlear model. To verify the safe insertion of the electrode array into the human cochlea, the contact pressures during insertion at the electrode tip and the contact pressures over the electrode length after insertion were calculated using a 3D finite element analysis. The results indicate that the SMA-embedded electrode is functionally and mechanically feasible for clinical applications. PMID:23762181

Min, Kyou Sik; Lim, Yoon Seob; Park, Se-Ik; Kim, Sung June

2013-01-01

358

Transparent ultra-hydrophobic surfaces  

Microsoft Academic Search

Self-cleaning surfaces have received a great deal of attention, both in research studies and commercial applications. Both transparent and non-transparent self-cleaning surfaces are highly desired, as they offer many advantages and their potential applications are endless. As in many other cases, also in the case of self-cleaning surfaces, nature found a solution before man. The Lotus flower is a symbol

P. F. Rios; H. Dodiuk; S. Kenig; S. McCarthy; A. Dotan

2007-01-01

359

Impedance spectroscopy on dye-sensitized solar cells with a poly(ethylenedioxythiophene):poly(styrenesulfonate) counter electrolyte  

NASA Astrophysics Data System (ADS)

We have successfully fabricated the dye-sensitized solar cell (DSSC) devices using ruthenium complex dye, polymer electrolytes, and poly(ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT: PSS) as a counter electrode. The overall power conversion efficiencies of the devices using polyethylene oxide (PEO), polyethylene glycol (PEG), polymethylmethacrylate (PMMA), and polyvinyl acetate (PVAc) as polymer electrolytes were 4.08%, 3.87%, 0.49%, and 0.20%, respectively, while the efficiencies of DSSC devices using Pt counter electrodes showed similar values of 5.7 0.1%. The differences in the efficiencies and the charge transfer resistances (R CT ) of the DSSCs with various polymer electrolytes and counter electrodes were measured by using an electrochemical impedance analyzer (EIS) and are discussed.

Kim, Young-Keun; Park, Sung-Hae; Hwang, Won-Pill; Seo, Min-Hye; Park, Hyun-Woo; Jang, Young-Wook; Kim, Mi-Ra; Lee, Jin-Kook

2012-06-01

360

Environmentally friendly disposable sensors with microfabricated on-chip planar bismuth electrode for in situ heavy metal ions measurement  

Microsoft Academic Search

This paper presents an environmentally friendly disposable heavy metal ion sensor for in situ and online monitoring in the nature and physiological systems. The miniaturized sensor chip consists of a non-toxic microfabricated bismuth (Bi) working electrode that replaces the conventional mercury electrodes, an integrated Ag\\/AgCl reference electrode, a gold counter electrode, and microfluidic channels. In this work, the electrochemical behavior

Zhiwei Zou; Am Jang; Eric MacKnight; Pei-Ming Wu; Paul L. Bishop; Chong H. Ahn

2008-01-01

361

Organic solar cells with carbon nanotube network electrodes Michael W. Rowell,a  

E-print Network

2006 We fabricated flexible transparent conducting electrodes by printing films of single-walled carbon, flexible polymer-fullerene bulk-heterojunction solar cells. The printing method produces relatively smooth/plastic show the SWNT/plastic electrodes to be far more flexible. © 2006 American Institute of Physics. DOI: 10

McGehee, Michael

362

Does mesoporosity enhance thin film properties? A question of electrode material for electrochromism of WO3.  

PubMed

Replacing the commonly used indium tin oxide (ITO) with a thin metal layer as a quasi-transparent electrode leads to enhancement and acceleration of the electrochromic response of WO(3), as otherwise there is an electronic activation barrier at the interface between WO(3) and the ITO electrode, impeding fast electron transfer. PMID:20644848

Ostermann, Rainer; Smarsly, Bernd

2009-11-01

363

Numerical modeling and design of single photon counter 4H-SiC avalanche photodiodes  

Microsoft Academic Search

We report device performance investigation of 4H-SiC avalanche photodiodes (APDs) with or without absorbing AlGaN cap layers, as 4H-SiCspsila potential use in single photon counter APDs have drawn interest. Wide bandgap 4H-SiC photodiodes have low dark current levels at high temperatures and under intense radiation compared to silicon, and the 4H-SiC APDs are ldquosolar blindrdquo - transparent to the sunpsilas

Akin Akturk; Neil Goldsman; Shahid Aslam; John Sigwarth; Fred Herrero

2008-01-01

364

COUNTER-CLOSURE Federico Luzzi  

E-print Network

to Closure, one that expresses a related and prima facie very plausible view: that knowledge obtained by the principle of Counter-Closure, that knowledge-yielding competent deductive inference must issue from known construct as exhibiting a justified, true belief to which none of the usual diagnoses of knowledge failure

Fitelson, Branden

365

ADMISSIONS COUNTER Berkeley, Ground Floor  

E-print Network

Catalogue Hayes Sources for the History of Irish Civilisation Short Loan (Counter Reserve) Collection TCD-938 Geology, Nursing & Midwifery, Business, History of Art, Music, Drama, Languages, Geography, History 940-977 History Non-Dewey Reserve Sequence MULTIMEDIA Area Microfiche/film collection and equipment DVD collection

O'Mahony, Donal E.

366

Counter-Rotating Accretion Discs  

E-print Network

Counter-rotating discs can arise from the accretion of a counter-rotating gas cloud onto the surface of an existing co-rotating disc or from the counter-rotating gas moving radially inward to the outer edge of an existing disc. At the interface, the two components mix to produce gas or plasma with zero net angular momentum which tends to free-fall towards the disc center. We discuss high-resolution axisymmetric hydrodynamic simulations of a viscous counter-rotating disc for cases where the two components are vertically separated and radially separated. The viscosity is described by an isotropic $\\alpha-$viscosity including all terms in the viscous stress tensor. For the vertically separated components a shear layer forms between them. The middle of this layer free-falls to the disk center. The accretion rates are increased by factors $\\sim 10^2-10^4$ over that of a conventional disc rotating in one direction with the same viscosity. The vertical width of the shear layer and the accretion rate are strongly dep...

Dyda, Sergei; Ustyugova, Galina V; Romanova, Marina M; Koldoba, Alexander V

2014-01-01

367

Monolithic Tandem Organic Photovoltaic Cell Utilizing Transparent Carbon Nanotube Interlayer  

NASA Astrophysics Data System (ADS)

We demonstrate an organic photovoltaic multijunction cell in a monolithic parallel tandem structure in which transparent multi and single-walled nanotube sheets are used as an interlayer electrode connecting two cells; polymeric photovoltaic (PPV) cell or organic low molecular PV (OPV). Each cell is characterized independently and the short circuit current density of the tandem is shown to be larger than individual cells for the PPV-MWCNT-OPC tandem*. Overall efficiency is increased attributed to effective use of transparent CNTs and enhanced spectral sensitivity due to differing active layer materials.Computer model circuit simulation is used to analyze the parameters of cells in parallel and series configurations. Advantages of a parallel connection is shown for PV cells with differing photocurrents. The PPV-CNT-PPV and OPV-CNT-OPV cells are also created and described. *S.Tanaka, K Mielczarek, et.al., APL. (submitted 2008, October).

Mielczarek, Kamil; Tanaka, Senku; Ovalle Robles, Raquel; Kuznetsov, Alexander; Wang, Brian; Hsu, Dean; Baughman, Ray; Zakhidov, Anvar

2009-03-01

368

Deposition of transparent conducting oxides for solar cells  

NASA Astrophysics Data System (ADS)

Transparent conductors are needed as the front surface electrodes in all types of solar cells. The electrical and optical performance of a transparent conductor may be rated by a figure of merit defined as the ratio of the electrical conductivity to the optical absorption coefficient of the layer. Fluorine-doped zinc oxide is shown to have the highest figure of merit. ZnO:F films with a sheet resistance of 5 ohms per square can have a visible absorption of less than 3 per cent. This high performance makes zinc oxide a candidate for replacing tin oxide in thin film amorphous silicon solar cells, or for replacing part of the highly-doped silicon layer in crystalline silicon solar cells. A new, cost-effective process is described for the chemical vapor deposition of ZnO:F at atmospheric pressure.

Gordon, Roy G.

1997-02-01

369

Polymer-dispersed liquid crystal devices using highly conducting polymers as electrodes  

NASA Astrophysics Data System (ADS)

Flexible all-organic polymer-dispersed liquid crystal (PDLC) devices were fabricated by using highly transparent and conductive poly(3,4-ethylenedioxy thiophene): p-toluene sulfonate (PEDOT:PTS) films, as electrode layers. These conductive PEDOT:PTS films have a high transparency up to 80%, and possess a very low sheet resistance of 100?sq-1 at 100nm thickness. We report on the fabrication and characterization of a PDLC device using a highly conductive PEDOT:PTS for the electrodes and demonstrate its superior performance relative to that of a similar device using the indium tin oxide layer as the electrodes.

Kim, Jin-Yeol; Woo, Hak-Yong; Baek, Ji-Woong; Kim, Tae-Wook; Song, Eun-Ah; Park, Su-Cheol; Ihm, Dae-Woo

2008-05-01

370

Basic Research Needs for Countering Terrorism  

SciTech Connect

To identify connections between technology needs for countering terrorism and underlying science issues and to recommend investment strategies to increase the impact of basic research on efforts to counter terrorism

Stevens, W.; Michalske, T.; Trewhella, J.; Makowski, L.; Swanson, B.; Colson, S.; Hazen, T.; Roberto, F.; David Franz, D.; Resnick, G.; Jacobson, S.; Valdez, J.; Gourley, P.; Tadros, M.; Sigman, M.; Sailor, M.; Ramsey, M.; Smith, B.; Shea, K.; Hrbek, J.; Rodacy, P.; Tevault, D.; Edelstein, N.; Beitz, J.; Burns, C.; Choppin, G.; Clark, S.; Dietz, M.; Rogers, R.; Traina, S.; Baldwin, D.; Thurnauer, M.; Hall, G.; Newman, L.; Miller, D.; Kung, H.; Parkin, D.; Shuh, D.; Shaw, H.; Terminello, L.; Meisel, D.; Blake, D.; Buchanan, M.; Roberto, J.; Colson, S.; Carling, R.; Samara, G.; Sasaki, D.; Pianetta, P.; Faison, B.; Thomassen, D.; Fryberger, T.; Kiernan, G.; Kreisler, M.; Morgan, L.; Hicks, J.; Dehmer, J.; Kerr, L.; Smith, B.; Mays, J.; Clark, S.

2002-03-01

371

Basic Research Needs for Countering Terrorism  

Microsoft Academic Search

To identify connections between technology needs for countering terrorism and underlying science issues and to recommend investment strategies to increase the impact of basic research on efforts to counter terrorism

W. Stevens; T. Michalske; J. Trewhella; L. Makowski; B. Swanson; S. Colson; T. Hazen; F. Roberto; D. David Franz; G. Resnick; S. Jacobson; J. Valdez; P. Gourley; M. Tadros; M. Sigman; M. Sailor; M. Ramsey; B. Smith; K. Shea; J. Hrbek; P. Rodacy; D. Tevault; N. Edelstein; J. Beitz; C. Burns; G. Choppin; S. Clark; M. Dietz; R. Rogers; S. Traina; D. Baldwin; M. Thurnauer; G. Hall; L. Newman; D. Miller; H. Kung; D. Parkin; D. Shuh; H. Shaw; L. Terminello; D. Meisel; D. Blake; M. Buchanan; J. Roberto; R. Carling; G. Samara; D. Sasaki; P. Pianetta; B. Faison; D. Thomassen; T. Fryberger; G. Kiernan; M. Kreisler; L. Morgan; J. Hicks; J. Dehmer; L. Kerr; J. Mays

2002-01-01

372

Simulation of two counter-propagating helium discharges at atmospheric pressure  

NASA Astrophysics Data System (ADS)

This paper presents 2D simulations showing the dynamics of interaction between two counter-propagating helium discharges at atmospheric pressure. The discharges were generated in two glass tubes separated by a few centimeters in ambient air. First, we applied the same voltage to each electrode wrapped around each discharge tube. Simulation results show that discharges ignite in tubes and then propagate, approaching each other without merging, as observed in experiments. Using the optical emission of discharges, we have determined the minimum distance of approach of counter-propagating discharges. This minimum distance is of the order of the tube diameter, and varies with the tube radius and inversely to the applied voltage. For conditions with different applied voltages on the electrodes, simulation results show a connection of both counter-propagating discharges with an increase in the discharge emission in the interaction region. For conditions with a time delay between the voltage applied on both electrodes, based on the optical emission of discharges, we have observed that counter-propagating discharges approach each other without merging. The minimum distance is of the order of the tube diameter, as in the reference case, without time delay between both applied voltages. However, simulation results show that the electron density in the interaction region between both discharge channels is about one order of magnitude higher than that for the reference case.

Jnsk, Jaroslav; Bourdon, Anne

2014-04-01

373

Indium-Tin Oxide/Al Reflective Electrodes for Ultraviolet Light-Emitting Diodes  

NASA Astrophysics Data System (ADS)

We investigated indium-tin oxide (ITO)/Al reflective electrodes for improving the light extraction efficiency of UV light-emitting diodes (LEDs). The ITO layer showed high transparency in the UV region upon optimization of the thickness and annealing temperature. As a result, the ITO/Al electrode exhibited both high reflectivity in the UV region and good contact characteristics simultaneously. Using this electrode, we succeeded in improving the light output power of a 350 nm UV-A LED.

Takehara, Kosuke; Takeda, Kenichiro; Ito, Shun; Aoshima, Hiroki; Iwaya, Motoaki; Takeuchi, Tetsuya; Kamiyama, Satoshi; Akasaki, Isamu; Amano, Hiroshi

2012-04-01

374

A transparent and stretchable graphene-based actuator for tactile display.  

PubMed

A tactile display is an important tool to help humans interact with machines by using touch. In this paper, we present a transparent and stretchable graphene-based actuator for advanced tactile displays. The proposed actuator is composed of transparent and compliant graphene electrodes and a dielectric elastomer substrate. Since the electrode is coated onto the appointed region of the substrate layer by layer, only the area of the dielectric elastomer substrate with electrodes bumps up in response to the input voltage, which consequently produces actuation. The actuator is proven to be operable while preserving its electrical and mechanical properties even under 25% stretching. Also, the simple fabrication of the proposed actuator is cost-effective and can easily be extended to multiple arrays. The actuator is expected to be applicable to various applications including tactile displays, vari-focal lenses etc. PMID:23511195

Kim, Uikyum; Kang, Junmo; Lee, Choonghan; Kwon, Hyeok Yong; Hwang, Soonhwi; Moon, Hyungpil; Koo, Ja Choon; Nam, Jae-Do; Hong, Byung Hee; Choi, Jae-Boong; Choi, Hyouk Ryeol

2013-04-12

375

Parallel counters for signed binary signals  

Microsoft Academic Search

A parallel counter is a combinational logic circuit that receives a set of binary count signals in parallel and determines the final count after some fixed delay. In this paper, a more general parallel counter is presented whose count inputs have three states (i.e. down, none, and up or, equivalently, -1, 0, and 1). Such parallel upldown counters find applications

Behrooz Parhami

1989-01-01

376

Quality control of liquid scintillation counters  

Microsoft Academic Search

Liquid scintillation counting (LSC) is widely used at LNHB for primary standardization of radionuclides (TDCR method), for secondary calibration and also for source stability studies or radioactive purity measurements. A total of five LSC counters are used for these purposes: two locally developed 3-photodetector counters for the implementation of the TDCR method, two Wallac 1414 counters and one Wallac 1220

F. Jaubert; I. Tarts; P. Cassette

2006-01-01

377

Bioanalysis with Potentiometric Membrane Electrodes.  

ERIC Educational Resources Information Center

Discusses major themes and interrelationships common to bioselective potentiometric membrane electrodes including the nature of bioselective electrodes, applications, and future prospects. Includes tables on traditional ion-selective membrane electrodes, nontraditional electrodes, and typical biocatalytic potentiometric electrodes. (Author/JN)

Rechnitz, G. A.

1982-01-01

378

Flexible Organic Light-Emitting Diodes on a Poly(3,4-ethylenedioxythiophene)/Metal-Grid Hybrid Electrode  

NASA Astrophysics Data System (ADS)

We fabricated flexible organic light-emitting diodes (OLEDs) on a transparent hybrid electrode. The electrode was prepared on a poly(ethylene naphthalate) (PEN) substrate and was composed of a poly(3,4-ethylenedioxythiophene) and aluminum grid. An efficient moisture-barrier structure was deposited underneath the electrode to protect the OLEDs from the moisture outgassed from the PEN substrate. The hybrid electrode showed sheet resistance and optical transmittance of 8.5 ?/square and 74%, respectively. The performance of the flexible OLEDs on a hybrid electrode with a moisture barrier was compared with that on a conventional indium tin oxide electrode with glass and plastic substrates.

Lee, Haksoo; Seo, Seung-Woo; Jung, Eun; Chae, Heeyeop; Cho, Sung Min

2013-04-01

379

Large-area transparent in visible range silicon carbide photodiode  

NASA Astrophysics Data System (ADS)

This paper describes the construction, fabrication and properties of large-area ultra violet detector that is transparent in the visible range. The device was made on n-type 4H SiC substrate with a double epitaxial layer in which aluminum was implanted to form a p-n junction close to the surface, and a SiO2 layer was formed for passivation, without a guard ring. The design of the top and bottom electrodes of 4mm diameter UV sensitive area allows not less than 20% visible range transmission. This transmission was measured across sensitive area of examined devices and was only 5% lower than that of the substrate before implantation and electrodes deposition.

Borecki, M.; Kociubi?ski, A.; Duk, M.; Kwietniewski, N.; Korwin-Pawlowski, M. L.; Doroz, P.; Szmidt, J.

2013-10-01

380

Transparent white organic light emitting diodes with improved cathode transparency  

NASA Astrophysics Data System (ADS)

We have fabricated transparent white organic light emitting diode (WOLED) for lighting application based on a hybrid white OLED and a phosphorescence white OLED. For the hybrid WOLED, a blue fluorescence emitting layer (FLEML) and green and red phosphorescence emitting layers (PH-EMLs) have been used in the device structure of ITO/hole transporting layer (HTL)/PH-EMLs/interlayer/FL-EML/ETL/LiF/Al. The balanced emissions from the FLEML and the PH-EMLs have been obtained by using appropriate carrier (hole) trapping effects in the PH-EMLs, which resulted in external and power efficiencies of 15 % and 27 lm/W, respectively, at a luminance of 1000 cd/m2 without any out-coupling enhancement. The Commission Internationale de L'Eclairage (CIE) coordinates of this hybrid WOLED is (0.43,0.44) with color rendering index (CRI) of 80 and correlated color temperature (CCT) of 3200 K, respectively, in the bottom emission structure. Based on this hybrid WOLED, we established highly efficient transparent WOLED by introduction of a transparent cathode, and obtained over 19 lm/W of power efficiency at a total luminance of 1000 cd/m2 as well as over 60 % of transmittance at 550 nm with the conventional glass encapsulation. Moreover, when the phosphorescent white OLED was combined with a transparent cathode, the power efficiency was reached up to 24 lm/W of power efficiency at a total luminance of 1000 cd/m2.

Lee, Jeong-Ik; Lee, Jonghee; Lee, Joowon; Shin, Jae-Heon; Hwang, Chi-Sun; Chu, Hye Yong

2009-08-01

381

HSPES membrane electrode assembly  

NASA Technical Reports Server (NTRS)

An improved fuel cell electrode, as well as fuel cells and membrane electrode assemblies that include such an electrode, in which the electrode includes a backing layer having a sintered layer thereon, and a non-sintered free-catalyst layer. The invention also features a method of forming the electrode by sintering a backing material with a catalyst material and then applying a free-catalyst layer.

Kindler, Andrew (Inventor); Yen, Shiao-Ping (Inventor)

2000-01-01

382

Boron-10 Lined Proportional Counter Wall Effects  

SciTech Connect

The Department of Energy Office of Nuclear Safeguards (NA-241) is supporting the project 'Coincidence Counting With Boron-Based Alternative Neutron Detection Technology' at Pacific Northwest National Laboratory (PNNL) for development of an alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a boron-lined proportional tube based system in the configuration of a coincidence counter. This report provides information about how variations in proportional counter radius and gas pressure in a typical coincident counter design might affect the observed signal from boron-lined tubes. A discussion comparing tubes to parallel plate counters is also included.

Siciliano, Edward R.; Kouzes, Richard T.

2012-05-01

383

Quality control of liquid scintillation counters.  

PubMed

Liquid scintillation counting (LSC) is widely used at LNHB for primary standardization of radionuclides (TDCR method), for secondary calibration and also for source stability studies or radioactive purity measurements. A total of five LSC counters are used for these purposes: two locally developed 3-photodetector counters for the implementation of the TDCR method, two Wallac 1414 counters and one Wallac 1220 Quantulus counter. The quality of the LSC measurements relies on the correct operation of these counters and their traceability to the frequency and time units. PMID:16621583

Jaubert, F; Tarts, I; Cassette, P

2006-01-01

384

Ultrathin oxidized Ti to increase stability and smoothness of Al doped ZnO transparent conductors for high efficiency indium-free polymer solar cells  

NASA Astrophysics Data System (ADS)

We propose a transparent electrode consisting of an aluminum doped zinc oxide (AZO) layer capped with an ultrathin oxidized Ti film for indium-free bulk-heterojunction polymer solar cells (PSCs). The oxidized Ti increases the chemical, environmental, stability and the surface smoothness of AZO while still maintaining its electrical and optical properties. The application potential of the proposed transparent electrode is demonstrated in an inverted PSC, which shows an efficiency of 6.3%, very close to the value (7%) obtained in a similar structure using indium tin oxide. This efficiency is the highest reported to date for PSCs incorporating AZO electrodes.

Formica, N.; Ghosh, D. S.; Martinez-Otero, A.; Chen, T. L.; Martorell, Jordi; Pruneri, V.

2013-10-01

385

Could Transparency Bring Economic Diversity?  

ERIC Educational Resources Information Center

The Spellings Commission report calls for greater access to higher education for low- and moderate-income students, greater transparency in the way higher education works and greater accountability for producing results. These recommendations are all significant in their own right, but the three concepts also converge to provide powerful support

Kahlenberg, Richard D.

2007-01-01

386

Flexible retinal electrode array  

DOEpatents

An electrode array which has applications for neural stimulation and sensing. The electrode array can include a large number of electrodes each of which is flexibly attached to a common substrate using a plurality of springs to allow the electrodes to move independently. The electrode array can be formed from a combination of bulk and surface micromachining, with electrode tips that can include an electroplated metal (e.g. platinum, iridium, gold or titanium) or a metal oxide (e.g. iridium oxide) for biocompatibility. The electrode array can be used to form a part of a neural prosthesis, and is particularly well adapted for use in an implantable retinal prosthesis where the electrodes can be tailored to provide a uniform gentle contact pressure with optional sensing of this contact pressure at one or more of the electrodes.

Okandan, Murat (Albuquerque, NM); Wessendorf, Kurt O. (Albuquerque, NM); Christenson, Todd R. (Albuquerque, NM)

2006-10-24

387

Micromachined electrode array  

DOEpatents

An electrode array is disclosed which has applications for neural stimulation and sensing. The electrode array, in certain embodiments, can include a plurality of electrodes each of which is flexibly attached to a common substrate using a plurality of springs to allow the electrodes to move independently. In other embodiments of the electrode array, the electrodes can be fixed to the substrate. The electrode array can be formed from a combination of bulk and surface micromachining, and can include electrode tips having an electroplated metal (e.g. platinum, iridium, gold or titanium) or a metal oxide (e.g. iridium oxide) for biocompatibility. The electrode array can be used to form a part of a neural prosthesis, and is particularly well adapted for use in an implantable retinal prosthesis.

Okandan, Murat (Edgewood, NM); Wessendorf, Kurt O. (Albuquerque, NM)

2007-12-11

388

High frequency reference electrode  

DOEpatents

A high frequency reference electrode for electrochemical experiments comprises a mercury-calomel or silver-silver chloride reference electrode with a layer of platinum around it and a layer of a chemically and electrically resistant material such as TEFLON around the platinum covering all but a small ring or "halo" at the tip of the reference electrode, adjacent to the active portion of the reference electrode. The voltage output of the platinum layer, which serves as a redox electrode, and that of the reference electrode are coupled by a capacitor or a set of capacitors and the coupled output transmitted to a standard laboratory potentiostat. The platinum may be applied by thermal decomposition to the surface of the reference electrode. The electrode provides superior high-frequency response over conventional electrodes.

Kronberg, James W. (Aiken, SC)

1994-01-01

389

THE FISSILE MATERIAL TRANSPARENCY TECHNOLOGY DEMONSTRATION (FMTTD)  

SciTech Connect

The United States Department of Defense, Defense Threat Reduction Agency Cooperative Threat Reduction program is supporting the construction of a fissile material storage facility at Mayak in the Russian Federation. Up to 34 tons of weapon-grade plutonium will be stored in the facility to await disposition. In order to meet arms control and nonproliferation objectives, the U.S. Congress has requested assurances that the nuclear material stored at the Mayak facility is derived from dismantled nuclear weapons. The usual approach to identify the origin or state of radioactive materials is to measure the intensity and energy of neutron and gamma radiation emitted. However, the Russian Federation considers such details as isotopic composition and mass to be classified. The solution arrived at by a DOE multilaboratory team is to place the radioactive specimen, the gamma and neutron counters, and all the computational equipment behind an information barrier. In the Fissile Materials Transparency Technology Demonstration (FMTD), this equipment was configured and programmed to measure the following six attributes: isotopic ratio, threshold mass, absence of oxide, presence of plutonium, age, and symmetry. On August 16, 2000, at Los Alamos National Laboratory, a delegation of Russian officials observed the successful demonstration of this new technology (called an Attribute Measurement System with Information Barrier, or AMS/IB). The scientists were able to demonstrate without releasing classified information that the nuclear material sample being tested (a nuclear weapon pit) had the declared weapon-grade plutonium characteristics. Once fully developed, AMS/IB technology will protect sensitive information while providing the United States increased confidence that the mandated Russian fissile materials have been stored. Attribute measurement systems can play a role in a number of U.S.-Russian nuclear security regimes such as the Trilateral Initiative, the Plutonium Production Reactor Agreement, and future strategic arms agreements. This paper discusses the details of this new inspection equipment, the August 2000 demonstration, and potential future applications.

L. R. AVENS; J. E. DOYLE; M. F. MULLEN

2001-06-01

390

Transparent Process Migration Sprite Operating System  

E-print Network

Transparent Process Migration in the Sprite Operating System Frederick Douglis Computer Science, California 94720 September 1990 #12; Transparent Process Migration in the Sprite Operating System Copyright c MICRO program. #12; ii Transparent Process Migration in the Sprite Operating System by Frederick Douglis

Douglis, Fred

391

An Implementation of Transparent Migration on  

E-print Network

An Implementation of Transparent Migration on Standard Scheme Eijiro Sumii University of Tokyo #12 Evaluation + Remote Evaluation Transparent Migration gorhost shift (revalrhost o tdpe()()) #12;Outline · What is transparent migration? · What are ­ Delimited continuation ­ Type-directed partial evaluation

Sumii, Eijiro

392

Transparent metals for ultrabroadband electromagnetic waves.  

PubMed

Making metals transparent, which could lead to fascinating applications, has long been pursued. Here we demonstrate that with narrow slit arrays metallic plates become transparent for extremely broad bandwidths; the high transmission efficiency is insensitive to the metal thickness. This work provides a guideline to develop novel devices, including transparent conducting panels, broadband metamaterials, and antireflective solar cells. PMID:22431279

Fan, Ren-Hao; Peng, Ru-Wen; Huang, Xian-Rong; Li, Jia; Liu, Yongmin; Hu, Qing; Wang, Mu; Zhang, Xiang

2012-04-17

393

Large-area graphene on polymer film for flexible and transparent anode in field emission device  

NASA Astrophysics Data System (ADS)

We present the fabrication and electrical characterization of large graphene structure on polyethylene terephthalate (PET) flexible substrate. Graphene film was grown on Cu foil by thermal chemical vapor deposition and transferred to PET by using hot press lamination. The graphene/PET film shows high quality, flexible transparent conductive structure with unique electrical-mechanical properties; 88.80% light transmittance and 1.1742 k?/sq sheet resistance. We demonstrate application of graphene/PET film as flexible and transparent electrode for field emission displays. Our proposed techniques can be tailored for any flexible substrate and large scale production, which could open up exciting device applications in foldable electronics.

Verma, Ved Prakash; Das, Santanu; Lahiri, Indranil; Choi, Wonbong

2010-05-01

394

Are shadows transparent? An investigation on white, shadows and transparency in pictures  

E-print Network

perception and transparency perception appear to use very similar rules, to the point that from: shadow perception; transparency perception; pictorial representation "No black, no white is transparent the visual phenomenon of transparency, for two reasons: rules for shadow perception as close kins of rules

Boyer, Edmond

395

Dry electrodes for electrocardiography.  

PubMed

Patient biopotentials are usually measured with conventional disposable Ag/AgCl electrodes. These electrodes provide excellent signal quality but are irritating for long-term use. Skin preparation is usually required prior to the application of electrodes such as shaving and cleansing with alcohol. To overcome these difficulties, researchers and caregivers seek alternative electrodes that would be acceptable in clinical and research environments. Dry electrodes that operate without gel, adhesive or even skin preparation have been studied for many decades. They are used in research applications, but they have yet to achieve acceptance for medical use. So far, a complete comparison and evaluation of dry electrodes is not well described in the literature. This work compares dry electrodes for biomedical use and physiological research, and reviews some novel systems developed for cardiac monitoring. Lastly, the paper provides suggestions to develop a dry-electrode-based system for mobile and long-term cardiac monitoring applications. PMID:24137716

Meziane, N; Webster, J G; Attari, M; Nimunkar, A J

2013-09-01

396

Corneal-shaping electrode  

SciTech Connect

The disclosure relates to a circulating saline electrode for changing corneal shape in eyes. The electrode comprises a tubular nonconductive electrode housing having an annular expanded base which has a surface substantially matched to a subject corneal surface. A tubular conductive electrode connected to a radiofrequency generating source is disposed within the electrode housing and longitudinally aligned therewith. The electrode has a generally hemispherical head having at least one orifice. Saline solution is circulated through the apparatus and over the cornea to cool the corneal surface while radiofrequency electric current emitted from the electrode flows therefrom through the cornea to a second electrode, on the rear of the head. This current heats the deep corneal stroma and thereby effects corneal reshaping as a biological response to the heat.

Doss, J.D.; Hutson, R.L.

1982-04-27

397

Study of the backside signal of micro-strip gas counters on electronic conducting glass  

Microsoft Academic Search

Microstrip gas counters (MSGC) on electronic conducting glass such as Schott S8900 have a very stable long-time behaviour. However, this glass is available in relatively thick plates only. A thick substrate limits the performances of two-dimensional detectors by attenuating the signal of the backside electrode which carries the second position coordinate. A structure with open cathodes, where the central area

G. Cicognani; D. Feltin; B. Guerard; A. Oed

1998-01-01

398

PTFOS: Flexible and Absorbable Intracranial Electrodes for Magnetic Resonance Imaging  

PubMed Central

Intracranial electrocortical recording and stimulation can provide unique knowledge about functional brain anatomy in patients undergoing brain surgery. This approach is commonly used in the treatment of medically refractory epilepsy. However, it can be very difficult to integrate the results of cortical recordings with other brain mapping modalities, particularly functional magnetic resonance imaging (fMRI). The ability to integrate imaging and electrophysiological information with simultaneous subdural electrocortical recording/stimulation and fMRI could offer significant insight for cognitive and systems neuroscience as well as for clinical neurology, particularly for patients with epilepsy or functional disorders. However, standard subdural electrodes cause significant artifact in MRI images, and concerns about risks such as cortical heating have generally precluded obtaining MRI in patients with implanted electrodes. We propose an electrode set based on polymer thick film organic substrate (PTFOS), an organic absorbable, flexible and stretchable electrode grid for intracranial use. These new types of MRI transparent intracranial electrodes are based on nano-particle ink technology that builds on our earlier development of an EEG/fMRI electrode set for scalp recording. The development of MRI-compatible recording/stimulation electrodes with a very thin profile could allow functional mapping at the individual subject level of the underlying feedback and feed forward networks. The thin flexible substrate would allow the electrodes to optimally contact the convoluted brain surface. Performance properties of the PTFOS were assessed by MRI measurements, finite difference time domain (FDTD) simulations, micro-volt recording, and injecting currents using standard electrocortical stimulation in phantoms. In contrast to the large artifacts exhibited with standard electrode sets, the PTFOS exhibited no artifact due to the reduced amount of metal and conductivity of the electrode/trace ink and had similar electrical properties to a standard subdural electrode set. The enhanced image quality could enable routine MRI exams of patients with intracranial electrode implantation and could also lead to chronic implantation solutions. PMID:22984396

Bonmassar, Giorgio; Fujimoto, Kyoko; Golby, Alexandra J.

2012-01-01

399

Gyromagnetically induced transparency of metasurfaces.  

PubMed

We demonstrate that the presence of a (gyro) magnetic substrate can produce an analog of electromagnetically induced transparency in Fano-resonant metamolecules. The simplest implementation of such gyromagnetically induced transparency (GIT) in a metasurface, comprised of an array of resonant antenna pairs placed on a gyromagnetic substrate and illuminated by a normally incident electromagnetic wave, is analyzed. Time reversal and spatial inversion symmetry breaking introduced by the dc magnetization makes metamolecules bianisotropic. This causes Fano interference between the otherwise uncoupled symmetric and antisymmetric resonances of the metamolecules giving rise to a sharp transmission peak through the otherwise reflective metasurface. We show that, for an oblique wave incidence, one-way GIT can be achieved by the combination of spatial dispersion and gyromagnetic effect. These theoretically predicted phenomena pave the way to nonreciprocal switches and isolators that can be dynamically controlled by electric currents. PMID:24702414

Mousavi, S Hossein; Khanikaev, Alexander B; Allen, Jeffery; Allen, Monica; Shvets, Gennady

2014-03-21

400

Dipole-Induced Electromagnetic Transparency  

NASA Astrophysics Data System (ADS)

We determine the optical response of a thin and dense layer of interacting quantum emitters. We show that, in such a dense system, the Lorentz redshift and the associated interaction broadening can be used to control the transmission and reflection spectra. In the presence of overlapping resonances, a dipole-induced electromagnetic transparency (DIET) regime, similar to electromagnetically induced transparency (EIT), may be achieved. DIET relies on destructive interference between the electromagnetic waves emitted by quantum emitters. Carefully tuning material parameters allows us to achieve narrow transmission windows in, otherwise, completely opaque media. We analyze in detail this coherent and collective effect using a generalized Lorentz model and show how it can be controlled. Several potential applications of the phenomenon, such as slow light, are proposed.

Puthumpally-Joseph, Raiju; Sukharev, Maxim; Atabek, Osman; Charron, Eric

2014-10-01

401

Dipole-induced electromagnetic transparency.  

PubMed

We determine the optical response of a thin and dense layer of interacting quantum emitters. We show that, in such a dense system, the Lorentz redshift and the associated interaction broadening can be used to control the transmission and reflection spectra. In the presence of overlapping resonances, a dipole-induced electromagnetic transparency (DIET) regime, similar to electromagnetically induced transparency (EIT), may be achieved. DIET relies on destructive interference between the electromagnetic waves emitted by quantum emitters. Carefully tuning material parameters allows us to achieve narrow transmission windows in, otherwise, completely opaque media. We analyze in detail this coherent and collective effect using a generalized Lorentz model and show how it can be controlled. Several potential applications of the phenomenon, such as slow light, are proposed. PMID:25361258

Puthumpally-Joseph, Raiju; Sukharev, Maxim; Atabek, Osman; Charron, Eric

2014-10-17

402

Low resistance fuel electrodes  

DOEpatents

An electrode 6 bonded to a solid, ion conducting electrolyte 5 is made, where the electrode 6 comprises a ceramic metal oxide 18, metal particles 17, and heat stable metal fibers 19, where the metal fibers provide a matrix structure for the electrode. The electrolyte 5 can be bonded to an air electrode cathode 4, to provide an electrochemical cell 2, preferably of tubular design.

Maskalick, Nichols J. (Pittsburgh, PA); Folser, George R. (Lower Burrell, PA)

1989-01-01

403

Transparency Homework: C. Scott Ananian  

E-print Network

Transparency Homework: Menomini C. Scott Ananian March 5, 2001 Menomini summary: iterativeId[short­V]. The following tableau shows that [a] is still properly opaque. Id fiId fiId *[high] & /sU:wA:nahki:qsIw/ [+ATR] [low] [short­V] Agree­L[ATR] Ident Ia. sU:wA:nahki:qsIw * b. su:wA:nahki:qsIw * * c. s

Ananian, C. Scott

404

Transparent conductor based on aluminum nanomesh  

NASA Astrophysics Data System (ADS)

We report a transparent conductor based on Al nanomesh, which was fabricated through Al anodization and etching processes. The Al anodization was performed at low temperature condition to slow down the anodization rate to achieve the well-controlled thickness of an Al nanomesh. By careful controlling of the anodization process, we can fabricate Al nanomesh transparent conductors with different sheet resistance and optical transparency in the visible spectrum range. We shall show that Al nanomesh transparent conductor is a strong contender for a transparent conductor dominated by ITO.

Kazarkin, B.; Mohammed, A. S.; Stsiapanau, A.; Zhuk, S.; Satskevich, Y.; Smirnov, A.

2014-10-01

405

Al nanogrid electrode for ultraviolet detectors.  

PubMed

Optical properties of Al nanogrids of different pitches and gaps were investigated both theoretically and experimentally. Three-dimensional finite-difference time-domain simulation predicted that surface plasmons at the air/Al interface would enhance ultraviolet transmission through the subwavelength gaps of the nanogrid, making it an effective electrode on GaN-based photodetectors to compensate for the lack of transparent electrode and high p-type doping. The predicted transmission enhancement was verified by confocal scanning optical microscopy performed at 365 nm. The quality of the nanogrids fabricated by electron-beam lithography was verified by near-field scanning optical microscopy and scanning electron microscopy. Based on the results, the pitch and gap of the nanogrids can be optimized for the best trade-off between electrical conductivity and optical transmission at different wavelengths. Based on different cutoff wavelengths, the nanogrids can also double as a filter to render photodetectors solar-blind. PMID:21931425

Ding, G; Deng, J; Zhou, L; Gan, Q; Hwang, J C M; Dierolf, V; Bartoli, F J; Mazuir, C; Schoenfeld, W V

2011-09-15

406

Near-Electrode Imager  

SciTech Connect

An apparatus, near-electrode imager, for employing nuclear magnetic resonance imaging to provide in situ measurements of electrochemical properties of a sample as a function of distance from a working electrode. The near-electrode imager use the radio frequency field gradient within a cylindrical toroid cavity resonator to provide high-resolution nuclear magnetic resonance spectral information on electrolyte materials.

Rathke, Jerome W.; Klingler, Robert J.; Woelk, Klaus; Gerald, Rex E.,II

1999-05-01

407

Insulated ECG electrodes  

NASA Technical Reports Server (NTRS)

Insulated, capacitively coupled electrode does not require electrolyte paste for attachment. Other features of electrode include wide range of nontoxic material that may be employed for dielectric because of sputtering technique used. Also, electrode size is reduced because there is no need for external compensating networks with FET operational amplifier.

Portnoy, W. M.; David, R. M.

1973-01-01

408

Near-electrode imager  

DOEpatents

An apparatus, near-electrode imager, for employing nuclear magnetic resonance imaging to provide in situ measurements of electrochemical properties of a sample as a function of distance from a working electrode. The near-electrode imager uses the radio frequency field gradient within a cylindrical toroid cavity resonator to provide high-resolution nuclear magnetic resonance spectral information on electrolyte materials.

Rathke, Jerome W. (Lockport, IL); Klingler, Robert J. (Westmont, IL); Woelk, Klaus (Wachtberg, DE); Gerald, II, Rex E. (Brookfield, IL)

2000-01-01

409

Optically transparent/colorless polyimides  

NASA Technical Reports Server (NTRS)

Several series of linear aromatic polyimide films have been synthesized and characterized with the objective of obtaining maximum optical transparency. Two approaches have been used as part of this structure-property relationship study. The first approach is to vary the molecular structure so as to separate chromophoric centers and reduce electronic interactions between polymer chains to lower the intensity of color in the resulting polymer films. A second and concurrent approach is to perform polymerizations with highly purified monomers. Glass transition temperatures of thermally cured polyimide films are obtained by thermomechanical analysis and thermal decomposition temperatures are determined by thermogravimetric analysis. Transmittance UV-visible spectra of the polyimide films are compared to that of a commercial polyimide film. Fully imidized films are tested for solubility in common organic solvents. The more transparent films prepared in this study are evaluated for use on second-surface mirror thermal control coating systems. Lightly colored to colorless films are characterized by UV-visible spectroscopy before and after exposure to 300 equivalent solar hours UV irradiation and varying doses of 1 MeV electron irradiation. The effects of monomer purity, casting solvent and cure atmosphere on polyimide film transparency are also investigated.

Stclair, A. K.; Stclair, T. L.; Slemp, W.; Ezzell, K. S.

1985-01-01

410

Compact fission counter for DANCE  

SciTech Connect

The Detector for Advanced Neutron Capture Experiments (DANCE) consists of 160 BF{sub 2} crystals with equal solid-angle coverage. DANCE is a 4{pi} {gamma}-ray calorimeter and designed to study the neutron-capture reactions on small quantities of radioactive and rare stable nuclei. These reactions are important for the radiochemistry applications and modeling the element production in stars. The recognition of capture event is made by the summed {gamma}-ray energy which is equivalent of the reaction Q-value and unique for a given capture reaction. For a selective group of actinides, where the neutron-induced fission reaction competes favorably with the neutron capture reaction, additional signature is needed to distinguish between fission and capture {gamma} rays for the DANCE measurement. This can be accomplished by introducing a detector system to tag fission fragments and thus establish a unique signature for the fission event. Once this system is implemented, one has the opportunity to study not only the capture but also fission reactions. A parallel-plate avalanche counter (PPAC) has many advantages for the detection of heavy charged particles such as fission fragments. These include fast timing, resistance to radiation damage, and tolerance of high counting rate. A PPAC also can be tuned to be insensitive to {alpha} particles, which is important for experiments with {alpha}-emitting actinides. Therefore, a PPAC is an ideal detector for experiments requiring a fast and clean trigger for fission. A PPAC with an ingenious design was fabricated in 2006 by integrating amplifiers into the target assembly. However, this counter was proved to be unsuitable for this application because of issues related to the stability of amplifiers and the ability to separate fission fragments from {alpha}'s. Therefore, a new design is needed. A LLNL proposal to develop a new PPAC for DANCE was funded by NA22 in FY09. The design goal is to minimize the mass for the proposed counter and still be able to maintain a stable operation under extreme radioactivity and the ability to separate fission fragments from {alpha}'s. In the following sections, the description is given for the design and performance of this new compact PPAC, for studying the neutron-induced reactions on actinides using DANCE at LANL.

Wu, C Y; Chyzh, A; Kwan, E; Henderson, R; Gostic, J; Carter, D; Bredeweg, T; Couture, A; Jandel, M; Ullmann, J

2010-11-06

411

Fabrication and Optoelectronic Properties of a Transparent ZnO Homostructural Light-Emitting Diode  

Microsoft Academic Search

A transparent ZnO homostructural light-emitting diode (LED) with a structure of Au electrode\\/p(i)-ZnO film\\/n-ZnO single crystal\\/In electrode was fabricated using the technique of N2O plasma-enhanced pulsed laser reactive deposition. The contact between the p(i)-ZnO layer and n-ZnO wafer was found to exhibit nonlinear and rectifying current-voltage (I-V) characteristics. A current injection emission with bluish-white light was clearly observed at room

Xin-Li Guo; Jae-Hyoung Choi; Hitoshi Tabata; Tomoji Kawai

2001-01-01

412

Dense Counter Machines and Verification Problems  

Microsoft Academic Search

We generalize the traditional definition of a multicounter machine (where the counters, which can only assume nonnegative integer values, can be incremented\\/decremented by 1 and tested for zero) by allowing the machine the additional ability to increment\\/decrement each counter Ci by a nondeterministi- cally chosen fractional amount ?i between 0 and 1 (?i may be different at each step). Further

Gaoyan Xie; Zhe Dang; Oscar H. Ibarra; Pierluigi San Pietro

2003-01-01

413

Reachability Problems for Dense Counter Machines  

Microsoft Academic Search

We generalize the traditional definition of a multicounter machine (where the counters, which can only assume nonnegative integer values, can be incremented\\/decremented by 1 and tested for zero) by allowing the machine the additional ability to increment\\/decrement the counters by a non- deterministically chosen fractional amount between 0 and 1 (the may be different at each step and need not

Gaoyan Xie; Zhe Dang; Oscar H. Ibarra; Pierluigi San Pietro

2003-01-01

414

Pressurized proportional counters for coincidence measurements  

Microsoft Academic Search

The experimental requirements for absolute measurements by 4 pi BETA ; gamma -coincidence counting with efficiency variation are outlined. In this ; context the use and operating characteristics of a pressurized 4 pi BETA -; proportional counter are considered. Basically, when the counter is pressurized, ; energetic BETA -particles deposit a larger fraction of their energies in the ; sensitive

A. Baerg

1973-01-01

415

Transparent polymer solar cells employing a layered light-trapping architecture  

NASA Astrophysics Data System (ADS)

Organic solar cells have unique properties that make them very attractive as a renewable energy source. Of particular interest are semi-transparent cells, which have the potential to be integrated into building faades yet not completely block light. However, making organic cells transparent limits the metal electrode thickness to a few nanometres, drastically reducing its reflectivity and the device photon-harvesting capacity. Here, we propose and implement an ad hoc path for light-harvesting recovery to bring the photon-to-charge conversion up to almost 80% that of its opaque counterpart. We report semi-transparent PTB7:PC71BM cells that exhibit 30% visible light transmission and 5.6% power conversion efficiency. Non-periodic photonic crystals are used to trap near-infrared and near-ultraviolet photons. By modifying the layer structure it is possible to tune the device colour without significantly altering cell performance.

Betancur, Rafael; Romero-Gomez, Pablo; Martinez-Otero, Alberto; Elias, Xavier; Maym, Marc; Martorell, Jordi

2013-12-01

416

Optical phase modulator utilizing a transparent piezofilm for use with the extrinsic fiber interferometer  

NASA Astrophysics Data System (ADS)

A piezoelectnc polyvinylidene flouride (PVF2) film with transparent indium tin oxide electrode metallization is placed directly in the path of a single mode fiber output, to form an extrinsic optical interferometer. This device can be used concurrently with another extrinsic inteferometer on a fiber directional coupler to generate a carrier phase modulation on which the signal phase shift is superimposed. Experimental results of the induced phase shifting coefficient are presented for two arrangements of the piezofilm differing in their boundary clamping conditions.

Sudarshanam, V. S.; Claus, Richard O.

1993-03-01

417

Over-the-counter Acne Treatments  

PubMed Central

Acne is a common dermatological disorder that most frequently affects adolescents; however, individuals may be affected at all ages. Many people who suffer from acne seek treatment from both prescription and over-the-counter acne medications. Due to convenience, lower cost, and difficulty getting an appointment with a dermatologist, the use of over-the-counter acne treatments is on the rise. As the plethora of over-the-counter acne treatment options can be overwhelming, it is important that dermatologists are well-versed on this subject to provide appropriate information about treatment regimens and potential drug interactions and that their patients see them as well-informed. This article reviews the efficacy of various over-the-counter acne treatments based on the current literature. A thorough literature review revealed there are many types of over-the-counter acne treatments and each are designed to target at least one of the pathogenic pathways that are reported to be involved in the development of acne lesions. Many of the key over-the-counter ingredients are incorporated in different formulations to broaden the spectrum and consumer appeal of available products. Unfortunately, many over-the-counter products are not well-supported by clinical studies, with a conspicuous absence of double-blind or investigator-blind, randomized, vehicle-controlled studies. Most studies that do exist on over-the-counter acne products are often funded by the manufacturer. Use of over-the-counter acne treatments is a mainstay in our society and it is important that dermatologists are knowledgeable about the different options, including potential benefits and limitations. Overall, over-the-counter acne therapies can be classified into the following five major groups: cleansers, leave-on products, mechanical treatments, essential oils, and vitamins. PMID:22808307

Graber, Emmy M.

2012-01-01

418

Thermal property of transparent silver nanowire films  

NASA Astrophysics Data System (ADS)

Through a comparison with transparent polymer composite films, we investigate the thermal property of transparent silver nanowire (AgNW) films that may be employed for heat sink in transparent electronic devices. To fabricate transparent polymer composite films and enhance their thermal property, poly(methyl methacrylate) (PMMA) solution featuring high transparency (?90%) and thermal emissivity (0.9) is mixed with thermal conductive fillers such as aluminum nitride (AlN) and silicon carbide (SiC). It is observed that the thermal emissivity of the AgNW films is decreased as the sheet resistance is reduced. However, we have found that the AgNW film shows the most excellent heat dissipation property (53.7 C) while maintaining relatively higher transparency (77.1% at 520 nm), followed by the PMMA:SiC and then PMMA:AlN films.

Park, J. W.; Shin, D. K.; Ahn, J.; Lee, J. Y.

2014-01-01

419

Electromechanically driven variable-focus lens based on transparent dielectric elastomer.  

PubMed

Dielectric elastomers with low elastic stiffness and high dielectric constant are smart materials that produce large strains (up to 300%) and belong to the group of electroactive polymers. Dielectric elastomer actuators are made from films of dielectric elastomers coated on both sides with compliant electrode material. Poly(3,4-ethylenedioxythiophene) (PEDOT), which is known as a transparent conducting polymer, has been widely used as an interfacial layer or polymer electrode in polymer electronic devices. In this study, we propose the transparent dielectric elastomer as a material of actuator driving variable-focus lens system using PEDOT as a transparent electrode. The variable-focus lens module has light transmittance up to 70% and maximum displacement up to 450. When voltage is applied to the fabricated lens module, optical focal length is changed. We anticipate our research to be a starting point for new model of variable-focus lens system. This system could find applications in portable devices, such as digital cameras, camcorder, and cell phones. PMID:22614602

Son, Sang-ik; Pugal, David; Hwang, Taeseon; Choi, Hyouk Ryeol; Koo, Ja Choon; Lee, Youngkwan; Kim, Kwang; Nam, Jae-Do

2012-05-20

420

21 CFR 864.5200 - Automated cell counter.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Automated cell counter. 864.5200 Section 864.5200...Hematology Devices 864.5200 Automated cell counter. (a) Identification. An automated cell counter is a fully-automated or...

2010-04-01

421

21 CFR 864.5220 - Automated differential cell counter.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Automated differential cell counter. 864.5220 Section 864... 864.5220 Automated differential cell counter. (a) Identification. An automated differential cell counter is a device used to...

2010-04-01

422

21 CFR 864.5200 - Automated cell counter.  

Code of Federal Regulations, 2013 CFR

...false Automated cell counter. 864.5200 Section...5200 Automated cell counter. (a) Identification. An automated cell counter is a fully-automated...These devices may also measure hemoglobin or hematocrit...devices may use either an electronic particle counting...

2013-04-01

423

The Principal and Staff Development: Countering the School Culture.  

ERIC Educational Resources Information Center

After addressing the problems inherent in developing staff improvement programs, the author offers starter planning steps for countering the energy drainage of teachers, countering the weak technology of teaching, and countering the feeling of aloneness of the teacher. (KC)

Martin, Mary; Rogus, Joseph F.

1979-01-01

424

Metamaterial transparency induced by cooperative electromagnetic interactions.  

PubMed

We propose a cooperative asymmetry-induced transparency, CAIT, formed by collective excitations in metamaterial arrays of discrete resonators. CAIT can display a sharp transmission resonance even when the constituent resonators individually exhibit broad resonances. We further show how dynamically reconfiguring the metamaterial allows one to actively control the transparency. While reminiscent of electromagnetically induced transparency, which can be described by independent emitters, CAIT relies on a cooperative response resulting from strong radiative couplings between the resonators. PMID:24138271

Jenkins, Stewart D; Ruostekoski, Janne

2013-10-01

425

Does mesoporosity enhance thin film properties? A question of electrode material for electrochromism of WO3  

NASA Astrophysics Data System (ADS)

Replacing the commonly used indium tin oxide (ITO) with a thin metal layer as a quasi-transparent electrode leads to enhancement and acceleration of the electrochromic response of WO3, as otherwise there is an electronic activation barrier at the interface between WO3 and the ITO electrode, impeding fast electron transfer.Replacing the commonly used indium tin oxide (ITO) with a thin metal layer as a quasi-transparent electrode leads to enhancement and acceleration of the electrochromic response of WO3, as otherwise there is an electronic activation barrier at the interface between WO3 and the ITO electrode, impeding fast electron transfer. Electronic supplementary information (ESI) available: Comparison of the variation of absorbance and charge inserted/extracted for WO3 films on gold and ITO. Electrochromic response of WO3 films of different thickness. See DOI: 10.1039/b9nr00091g

Ostermann, Rainer; Smarsly, Bernd

2009-11-01

426

Transparent communications permit unmanned operations  

SciTech Connect

Not-normally-manned platforms are not a new development. However, their use in harsher environments has until recently, been limited. Development of reliable communications networks capable of handling the large amounts of data required for process control in real time with distributed control systems (DCSs) has been a key factor in making the concept viable for harsher, more remote environments. The article below examines the transparent communications network and DCS installed on Pickerill field, offshore UK, by Fisher-Rosemount Systems and its operational parameters. Pickerill field, some 50 mi off the Lincolnshire coast, comprises two small unmanned platforms producing gas under remote control from Arco`s operations base at Great Yarmouth about 60 mi south. Reliable communication is required both with the two platforms offshore and with Conoco`s gas processing operators at Theddlethorpe. Fundamental to project success was the ability of the process control system to provide entirely secure and transparent communication with equipment offshore and thus enable operators at Great Yarmouth to interact with the process as if it were local to their control center.

NONE

1995-07-01

427

Speed Judgements of Transparent Stimuli  

NASA Technical Reports Server (NTRS)

When two moving patterns are combined additively, observers often perceive two transparent surfaces, even when there are no cues supporting this segmentation in a frozen snapshot. We examined the ability of observers to make quantitative judgments about the speed of one of the patterns under these conditions. The component patterns consisted of band-pass filtered random noise presented in a spatial Gaussian contrast envelope, presented for 250 ms. On each trial a standard pattern appeared on one side of the fixation point, while a test pattern appeared on the other. The test pattern moved in the same direction as the standard, but with a speed which varied from trial to trial using a staircase procedure. The subjects' task was to report the side of the fixation point on which faster motion was seen. In some conditions the test stimulus was made to appear transparent by adding a mask pattern. When the mask was stationary, or moved slowly with respect to the test, no significant biases were introduced and discrimination performance was comparable to the no-mask condition (typically 3%). If the mask moved over the test with similar speed, however, the task became much harder, regardless of whether the mask moved opposite or orthogonal to the test. (Some subjects commented on a perceived directional repulsion between tests and orthogonally moving masks.) These results suggest the use of non-directional temporal channels in the performance of the speed discrimination task.

Mulligan, Jeffrey B.; Null, Cynthia H. (Technical Monitor)

1996-01-01

428

Bifunctional alkaline oxygen electrodes  

NASA Technical Reports Server (NTRS)

The authors describe the identification and testing of electrocatalysts and supports for the positive electrode of moderate-temperature, single-unit, rechargeable alkaline fuel cells. Recent work on Na(x)Pt3O4, a potential bifunctional catalyst, is described, as well as the application of novel approaches to the development of more efficient bifunctional electrode structures. The three dual-character electrodes considered here showed similar superior performance; the Pt/RhO2 and Rh/RhO2 electrodes showed slightly better performance than the Pt/IrO2 electrode. It is concluded that Na(x)Pt3O4 continues to be a promising bifunctional oxygen electrode catalyst but requires further investigation and development.

Swette, L.; Kackley, N.; Mccatty, S. A.

1991-01-01

429