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1

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

SciTech Connect

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

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

2012-12-15

2

Transparent metal selenide alloy counter electrodes for high-efficiency bifacial dye-sensitized solar cells.  

PubMed

The exploration of cost-effective and transparent counter electrodes (CEs) is a persistent objective in the development of bifacial dye-sensitized solar cells (DSSCs). Transparent counter electrodes based on binary-alloy metal selenides (M-Se; M=Co, Ni, Cu, Fe, Ru) are now obtained by a mild, solution-based method and employed in efficient bifacial DSSCs. Owing to superior charge-transfer ability for the I(-) /I3 (-) redox couple, electrocatalytic activity toward I3 (-) reduction, and optical transparency, the bifacial DSSCs with CEs consisting of a metal selenide alloy yield front and rear efficiencies of 8.30?% and 4.63?% for Co0.85 Se, 7.85?% and 4.37?% for Ni0.85 Se, 6.43?% and 4.24?% for Cu0.50 Se, 7.64?% and 5.05?% for FeSe, and 9.22?% and 5.90?% for Ru0.33 Se in comparison with 6.18?% and 3.56?% for a cell with an electrode based on pristine platinum, respectively. Moreover, fast activity onset, high multiple start/stop capability, and relatively good stability demonstrate that these new electrodes should find applications in solar panels. PMID:25358619

Duan, Yanyan; Tang, Qunwei; Liu, Juan; He, Benlin; Yu, Liangmin

2014-12-22

3

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

PubMed

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

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

2012-01-11

4

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

NASA Astrophysics Data System (ADS)

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

Ku, Zhiliang; Rong, Yaoguang; Han, Hongwei

2013-10-01

5

Transparent graphene\\/PEDOTPSS composite films as counter electrodes of dye-sensitized solar cells  

Microsoft Academic Search

Composite films of graphene and polystyreneslufonate doped poly(3,4-ethylenedioxythiophene) (graphene\\/PEDOTPSS) were deposited on indium tin oxide (ITO) substrates by spin coating at room temperature and applied as counter electrodes of dye-sensitized solar cells (DSSCs). A 60nm thick composite film (contained 1wt% graphene) coated ITO electrode exhibited high transmittance (>80%) at visible wavelengths and high electrocatalytic activity. The energy conversion efficiency of

Wenjing Hong; Yuxi Xu; Gewu Lu; Chun Li; Gaoquan Shi

2008-01-01

6

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

7

Cost-effective bifacial dye-sensitized solar cells with transparent iron selenide counter electrodes. An avenue of enhancing rear-side electricity generation capability  

NASA Astrophysics Data System (ADS)

Alloy materials have established themselves as alternative electrocatalysts for electrochemical devices because of their cost-effectiveness, high conductivity, good electrocatalytic activity, and reasonable stability. Aiming at reducing fabrication cost without sacrificing power conversion efficiency of dye-sensitized solar cells (DSSCs), we report the feasibility of designing transparent and cost-effective Fe-Se alloy counter electrodes for bifacial DSSCs. Due to the rapid charge transfer ability and electrocatalytic activity, maximum front and rear efficiencies of 7.64% and 4.95% are measured for the DSSC with FeSe alloy electrode in comparison with 6.97% and 3.56% from Pt-based solar cell. The impressive results along with simple synthesis highlight the potential application of Fe-Se alloys in robust bifacial DSSCs.

Liu, Juan; Tang, Qunwei; He, Benlin; Yu, Liangmin

2015-02-01

8

Electrochromic counter electrode  

DOEpatents

The present invention discloses an amorphous material comprising nickel oxide doped with tantalum that is an anodically coloring electrochromic material. The material of the present invention is prepared in the form of an electrode (200) having a thin film (202) of an electrochromic material of the present invention residing on a transparent conductive film (203). The material of the present invention is also incorporated into an electrochromic device (100) as a thin film (102) in conjunction with a cathodically coloring prior art electrochromic material layer (104) such that the devices contain both anodically coloring (102) and cathodically coloring (104) layers. The materials of the electrochromic layers in these devices exhibit broadband optical complimentary behavior, ionic species complimentary behavior, and coloration efficiency complimentary behavior in their operation.

Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland; Jorgensen, Gary J.

2005-02-22

9

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

10

A facile synthesis of bimetallic AuPt nanoparticles as a new transparent counter electrode for quantum-dot-sensitized solar cells  

NASA Astrophysics Data System (ADS)

This study first reports the synthesis of AuPt bimetallic nanoparticles (AuPt-BNPs) on an FTO glass substrate using dry plasma reduction (DPR) and its application as an alternative transparent counter electrode (CE) for quantum-dot-sensitized solar cells (QDSCs) operated under bi-side illumination. DPR is an economically feasible and ecologically sustainable method. The formation of ultrafine crystalline AuPt-BNPs on an FTO substrate is confirmed through TEM, HRTEM with HAADF-STEM and HAADF-STEM-EDS analyses. The mechanism for controlling the size, mono-dispersity, and areal number density of nanoparticles on the substrate surface is suggested. The CE fabricated with AuPt-BNPs exhibits a high electro-catalytic activity without losing the optical transmittance of the FTO substrate. The QDSC employing the AuPt-BNP electrode reaches efficiencies of 2.4% under front-side illumination and 2.2% under back-side illumination. Bi-side illumination yields an efficiency of 3.4%, which is comparable to an efficiency of 3.7% obtained for the QDSC with the state-of-the-art CE.

Dao, Van-Duong; Choi, Youngwoo; Yong, Kijung; Larina, Liudmila L.; Shevaleevskiy, Oleg; Choi, Ho-Suk

2015-01-01

11

Transparent electrode for optical switch  

DOEpatents

A low pressure gas electrode utilizing ionized gas in a glow discharge regime forms a transparent electrode for electro-optical switches. The transparent electrode comprises a low pressure gas region on both sides of the crystal. When the gas is ionized, e.g., by a glow discharge in the low pressure gas, the plasma formed is a good conductor. The gas electrode acts as a highly uniform conducting electrode. Since the plasma is transparent to a high energy laser beam passing through the crystal, the electrode is a transparent electrode. A crystal exposed from two sides to such a plasma can be charged up uniformly to any desired voltage. The plasma can be created either by the main high voltage pulser used to charge up the crystal or by auxiliary discharges or external sources of ionization. A typical configuration utilizes 10 torr argon in the discharge region adjacent to each crystal face.

Goldhar, Julius (San Ramon, CA); Henesian, Mark A. (Livermore, CA)

1986-01-01

12

Transparent conducting oxide semiconductors for transparent electrodes  

Microsoft Academic Search

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

Tadatsugu Minami

2005-01-01

13

Optical and structural properties of sol gel made Ce/Ti/Zr mixed oxide thin films as transparent counter electrode for electrochromic devices  

NASA Astrophysics Data System (ADS)

Ce/Ti/Zr mixed oxide thin films were prepared using sol-gel process with mole ratios from 45/5 to 5/45 of Ti/Zr and 50 of Ce and deposited by dip coating technique. Optical, electrochromic, and structural properties of such films were investigated. The thickness, refractive index, and extinction coefficient of the films were calculated through transmission and reflection measurement by an nkd spectrophotometer. The surface morphology and structural behaviors of the films were characterized by atomic force microscopy and X-ray diffraction. Cyclic voltammetry measurements also were used to study electrochromic properties of these films. The best counter electrode Ce/Ti/Zr oxide thin film is achieved for the sample with a mole ratio of 40/10 of Ti/Zr. The ratio between anodic and cathodic charge is about 0.95 for this sample with a surface roughness of 1.8 nm.

Ghodsi, F. E.; Tepehan, F. Z.; Tepehan, G. G.

2008-09-01

14

3?D single-walled carbon nanotube/graphene aerogels as pt-free transparent counter electrodes for high efficiency dye-sensitized solar cells.  

PubMed

3D single-walled carbon nanotube (SWCNT)/graphene aerogel (NGS) was synthesized and used as an alternative to platinized fluorine-doped tin oxide (FTO) in dye-sensitized solar cells (DSSCs). An island-like structure formed on the FTO using the spin-coating method, leading to a transmittance (49.86?% at 671?nm). The resulting NGS-based counter electrodes (CEs) exhibited excellent power conversion efficiency (PCE) (8.31?%) compared to Pt (7.56?%). Surprisingly, PCE increased to 9.64?% under assisted by a mirror; The excellent performance of DSSCs can be attributed to the high electrical conductivity and good electrocatalytic activity induced by the SWCNTs and the excellent catalytic properties of graphene, coupled with the 3D structure with a larger surface area and good surface hydrophilicity for increased electrolyte-electrode interactions and electrolyte/reactant diffusion. Hence, our results demonstrate that 3D-NGS materials have considerable potential for DSSC-related applications and merit further investigation. PMID:25351578

Ma, Jie; Li, Cheng; Yu, Fei; Chen, Junhong

2014-12-01

15

Optical impedance transformer for transparent conducting electrodes.  

PubMed

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

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

2014-05-14

16

Metal nanowire-graphene composite transparent electrodes  

NASA Astrophysics Data System (ADS)

Silver nanowires with 40 nm diameter and copper nanowires with 150 nm diameter were synthesized using low-temperature routes, and deposited in combination with ultrathin graphene sheets for use as transparent conductors. A systematic and detailed analysis involving nature of capping agent for the metal nanowires, annealing of deposited films, and pre-treatment of substrates revealed critical conditions necessary for preparing high performance transparent conducting electrodes. The best electrodes show ~90% optical transmissivity and sheet resistance of ~10 ?/?, already comparable to the best available transparent electrodes. The metal nanowire-graphene composite electrodes are therefore well suited for fabrication of opto-electronic and electronic devices.

Mankowski, Trent; Zhu, Zhaozhao; Balakrishnan, Kaushik; Shikoh, Ali Sehpar; Touati, Farid; Benammar, Mohieddine; Mansuripur, Masud; Falco, Charlies M.

2014-10-01

17

Nanopatterned Metallic Films for Use As Transparent Conductive Electrodes in  

E-print Network

Nanopatterned Metallic Films for Use As Transparent Conductive Electrodes in Optoelectronic Devices metallic films as transparent conductive electrodes in optoelectronic devices. We find that the physics to two-dimensional patterns. KEYWORDS Transparent conductive electrodes, nanopatterned metal films, sheet

Fan, Shanhui

18

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

19

Manipulating nanowire assembly for flexible transparent electrodes.  

PubMed

Manipulating nanowire assembly could help the design of hierarchical structures with unique functionalities. Herein, we first report a facile solution-based process under ambient conditions for co-assembling two kinds of nanowires which have suitable composition and functionalities, such as Ag and Te nanowires, for the fabrication of flexible transparent electrodes. Then Te nanowires can be etched away easily, leaving Ag nanowire networks with controllable pitch. By manipulating the assembly of Ag and Te nanowires, we can precisely tailor and balance the optical transmittance and the conductivity of the resulting flexible transparent electrodes. The network of Ag nanowires which have tunable pitch forms a flexible transparent conducting electrode with an averaged transmission of up to 97.3?% and sheet resistances as low as 2.7??/sq under optimized conditions. The work provides a new way for tailoring the properties of nanowire-based devices. PMID:25283948

Liu, Jian-Wei; Wang, Jin-Long; Wang, Zhi-Hua; Huang, Wei-Ran; Yu, Shu-Hong

2014-12-01

20

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

21

Copper Nanowires as Fully Transparent Conductive Electrodes  

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

22

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 and fabricate a new kind of transparent conducting electrode that exhibits both superior optoelectronic suitability of our transparent conducting electrode by fabricating a flexible touch-screen device

Cui, Yi

23

Transparent metallic fractal electrodes for semiconductor devices.  

PubMed

Nanostructured metallic films have the potential to replace metal oxide films as transparent electrodes in optoelectronic devices. An ideal transparent electrode should possess a high, broadband, and polarization-independent transmittance. Conventional metallic gratings and grids with wavelength-scale periodicities, however, do not have all of these qualities. Furthermore, the transmission properties of a nanostructured electrode need to be assessed in the actual dielectric environment provided by a device, where a high-index semiconductor layer can reflect a substantial fraction of the incident light. Here we propose nanostructured aluminum electrodes with space-filling fractal geometries as alternatives to gratings and grids and experimentally demonstrate their superior optoelectronic performance through integration with Si photodetectors. As shown by polarization and spectrally resolved photocurrent measurements, devices with fractal electrodes exhibit both a broadband transmission and a flat polarization response that outperforms both square grids and linear gratings. Finally, we show the benefits of adding a thin silicon nitride film to the nanostructured electrodes to further reduce reflection. PMID:25140611

Afshinmanesh, Farzaneh; Curto, Alberto G; Milaninia, Kaveh M; van Hulst, Niek F; Brongersma, Mark L

2014-09-10

24

Transparent electrode materials for solar cells  

Microsoft Academic Search

Alternatives for replacing the expensive ITO are explored and Poly(ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS) is introduced as one possibility. We present the first small-molecule organic solar cells employing only PEDOT:PSS as transparent electrode. Solar cells on glass and on flexible plastic foil were prepared, using a p-doped hole transporting material, zinc phthalocyanine (ZnPc) and C60 as donor-acceptor heterojunction, and an exciton

Jan Meiss; Christian L. Uhrich; Karsten Fehse; Steffen Pfuetzner; Moritz K. Riede; Karl Leo

2008-01-01

25

Electrolessly deposited electrospun metal nanowire transparent electrodes.  

PubMed

Metal nanowire (MNW) transparent electrodes have been widely developed for their promising sheet resistance (R(s))-transmittance (T) performance, excellent mechanical flexibility, and facile synthesis. How to lower the junction resistance without compromising optical transmittance has become the key issue in enhancing their performance. Here we combine electrospinning and electroless deposition to synthesize interconnected, ultralong MNW networks. For both silver and copper nanowire networks, the R(s) and T values reach around 10 ?/sq and 90%, respectively. This process is scalable and takes place at ambient temperature and pressure, which opens new opportunities for flexible electronics and roll-to-roll large-scale manufacturing. PMID:25019606

Hsu, Po-Chun; Kong, Desheng; Wang, Shuang; Wang, Haotian; Welch, Alex J; Wu, Hui; Cui, Yi

2014-07-30

26

Transparent electrode materials for solar cells  

NASA Astrophysics Data System (ADS)

Alternatives for replacing the expensive ITO are explored and Poly(ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS) is introduced as one possibility. We present the first small-molecule organic solar cells employing only PEDOT:PSS as transparent electrode. Solar cells on glass and on flexible plastic foil were prepared, using a p-doped hole transporting material, zinc phthalocyanine (ZnPc) and C60 as donor-acceptor heterojunction, and an exciton blocking layer. Different methods to structure the PEDOT:PSS electrodes were investigated and are presented. As proof of principle, non-optimized prototype cells with efficiencies of over 0.7% on glass and 0.9% on flexible plastic foil substrate were obtained.

Meiss, Jan; Uhrich, Christian L.; Fehse, Karsten; Pfuetzner, Steffen; Riede, Moritz K.; Leo, Karl

2008-04-01

27

Electrowetting devices with transparent single-walled carbon nanotube electrodes  

E-print Network

- parent to be seen or observed, requiring transparent and elec- trically conducting substrates. Indium tin. Transparent and conducting films made of randomly dis- tributed single-walled carbon nanotubes SWCNTs haveElectrowetting devices with transparent single-walled carbon nanotube electrodes Liangbing Hu

Gruner, George

28

Graphene Transparent Conductive Electrodes for Next- Generation Microshutter Arrays  

NASA Technical Reports Server (NTRS)

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

Li, Mary; Sultana, Mahmooda; Hess, Larry

2012-01-01

29

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

30

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

31

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

32

Transparent nanoporous tin-oxide film electrode fabricated by anodization  

Microsoft Academic Search

A transparent nanoporous tin oxide film electrode was fabricated by anodizing a tin film on a fluorine-doped tin oxide (FTO) film electrode. The resulting anodized nanoporous tin oxide (ANPTO) film has columnar-type pore channels with around 50nm in diameter and is optically transparent. Electrochemical measurements with Fe(CN)63? as a redox probe clearly revealed that the ANPTO film could be used

Akira Yamaguchi; Teruhiko Iimura; Kazuhiro Hotta; Norio Teramae

2011-01-01

33

Graphene-based transparent electrodes for hybrid solar cells  

NASA Astrophysics Data System (ADS)

The graphene-based transparent and conductive films were demonstrated to be cost-effective electrodes working in organic-inorganic hybrid Schottky solar cells. Large area graphene films were produced by chemical vapor deposition (CVD) on copper foils and transferred onto glass as transparent electrodes. The hybrid solar cell devices consist of solution processed poly (3, 4-ethlenedioxythiophene): poly (styrenesulfonate) (PEDOT: PSS) which is sandwiched between silicon wafer and graphene electrode. The solar cells based on graphene electrodes, especially those doped with HNO3, has comparable performance to the reference devices using commercial indium tin oxide (ITO). Our work suggests that graphene-based transparent electrode is a promising candidate to replace ITO.

Li, Pengfei; Chen, Caiyun; Zhang, Jie; Li, Shaojuan; Sun, Baoquan; Bao, Qiaoliang

2014-11-01

34

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

35

Single-Wall Carbon Nanotubes as Transparent Electrodes for Photovoltaics  

SciTech Connect

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

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

2006-01-01

36

Single-Wall Carbon Nanotubes as Transparent Electrodes for Photovoltaics  

Microsoft Academic Search

Transparent and electrically conductive coatings and films have a variety of uses in the fast-growing field of optoelectronic applications. Transparent electrodes typically include semiconductive metal oxides such as indium tin oxide (ITO), and conducting polymers such as poly(3,4-ethylenedioxythiophene), doped and stabilized with poly(styrenesulfonate) (PEDOT\\/PSS). In recent years, Eikos, Inc. has conceived and developed technologies to deliver novel alternatives using single-wall

Jorma Peltola; Igor Levitsky; Paul Glatkowski; Jao van de Lagemaat; Garry Rumbles; Teresa Barnes; Tim Coutts

2006-01-01

37

Polymer-metal hybrid transparent electrodes for flexible electronics.  

PubMed

Despite nearly two decades of research, the absence of ideal flexible and transparent electrodes has been the largest obstacle in realizing flexible and printable electronics for future technologies. Here we report the fabrication of 'polymer-metal hybrid electrodes' with high-performance properties, including a bending radius <1?mm, a visible-range transmittance>95% and a sheet resistance <10???sq(-1). These features arise from a surface modification of the plastic substrates using an amine-containing nonconjugated polyelectrolyte, which provides ideal metal-nucleation sites with a surface-density on the atomic scale, in combination with the successive deposition of a facile anti-reflective coating using a conducting polymer. The hybrid electrodes are fully functional as universal electrodes for high-end flexible electronic applications, such as polymer solar cells that exhibit a high power conversion efficiency of 10% and polymer light-emitting diodes that can outperform those based on transparent conducting oxides. PMID:25790133

Kang, Hongkyu; Jung, Suhyun; Jeong, Soyeong; Kim, Geunjin; Lee, Kwanghee

2015-01-01

38

Polymer-metal hybrid transparent electrodes for flexible electronics  

PubMed Central

Despite nearly two decades of research, the absence of ideal flexible and transparent electrodes has been the largest obstacle in realizing flexible and printable electronics for future technologies. Here we report the fabrication of polymer-metal hybrid electrodes with high-performance properties, including a bending radius <1?mm, a visible-range transmittance>95% and a sheet resistance <10???sq?1. These features arise from a surface modification of the plastic substrates using an amine-containing nonconjugated polyelectrolyte, which provides ideal metal-nucleation sites with a surface-density on the atomic scale, in combination with the successive deposition of a facile anti-reflective coating using a conducting polymer. The hybrid electrodes are fully functional as universal electrodes for high-end flexible electronic applications, such as polymer solar cells that exhibit a high power conversion efficiency of 10% and polymer light-emitting diodes that can outperform those based on transparent conducting oxides. PMID:25790133

Kang, Hongkyu; Jung, Suhyun; Jeong, Soyeong; Kim, Geunjin; Lee, Kwanghee

2015-01-01

39

Electrospun Metal Nanofiber Webs as High-Performance Transparent Electrode  

E-print Network

-processed networks of nanostructures such as carbon nanotubes (CNTs), graphene, and silver nanowires have attracted, and silver is relatively expensive. Here, we show high-performance transparent electrodes with copper nanofiber networks by a low-cost and scalable electrospinning process. Copper nanofibers have ultrahigh

Cui, Yi

40

Transparent conductive electrodes for electrochromic devices: A review  

Microsoft Academic Search

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

C. G. Granqvist

1993-01-01

41

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

42

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

43

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

44

Photovoltachromic device with a micropatterned bifunctional counter electrode.  

PubMed

A photovoltachromic window can potentially act as a smart glass skin which generates electric energy as a common dye-sensitized solar cell and, at the same time, control the incoming energy flux by reacting to even small modifications in the solar radiation intensity. We report here the successful implementation of a novel architecture of a photovoltachromic cell based on an engineered bifunctional counter electrode consisting of two physically separated platinum and tungsten oxide regions, which are arranged to form complementary comb-like patterns. Solar light is partially harvested by a dye-sensitized photoelectrode made on the front glass of the cell which fully overlaps a bifunctional counter electrode made on the back glass. When the cell is illuminated, the photovoltage drives electrons into the electrochromic stripes through the photoelectrochromic circuit and promotes the Li(+) diffusion towards the WO3 film, which thus turns into its colored state: a photocoloration efficiency of 17 cm(2) min(-1) W(-1) at a wavelength of 650 nm under 1.0 sun was reported along with fast response (coloration time <2 s and bleaching time <5 s). A fairly efficient photovoltaic functionality was also retained due to the copresence of the independently switchable micropatterned platinum electrode. PMID:24460118

Cannavale, Alessandro; Manca, Michele; De Marco, Luisa; Grisorio, Roberto; Carallo, Sonia; Suranna, Gian Paolo; Gigli, Giuseppe

2014-02-26

45

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

46

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

47

Two-dimensional metamaterial transparent metal electrodes for infrared optoelectronics.  

PubMed

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

Clark, Samuel M; Han, Sang Eon

2014-06-15

48

Carbon microspheres via microwave-assisted synthesis as counter electrodes of dye-sensitized solar cells.  

PubMed

Carbon microspheres (CSs) were successfully fabricated and used as counter electrodes of dye-sensitized solar cells (DSSCs). CSs were obtained through a fast microwave-assisted approach using sucrose as the precursor in a microwave system and subsequent thermal treatment at 600, 800 and 1000C. A maximum photovoltaic conversion efficiency of 5.5% is achieved for DSSCs based on the CSs counter electrodes, which is comparable to the cell based on conventional Pt counter electrode at one sun (AM 1.5G, 100mWcm(-2)). The results suggest the CSs to be a potential candidate for counter electrodes of DSSCs. PMID:25643959

Sun, Hengchao; Chen, Taiqiang; Liu, Yong; Hou, Xian; Zhang, Li; Zhu, Guang; Sun, Zhuo; Pan, Likun

2015-05-01

49

Angle-specific transparent conducting electrodes with metallic gratings  

SciTech Connect

Transparent conducting electrodes, which are not made from indium tin oxide, and which display a strong angular dependence are useful for various technologies. Here, we introduce a tilted silver grating that combines a large conductance with a strong and angle-specific transmittance. When the light incidence angle matches the tilt angle of the grating, transmittance is close to the maximum along a very broadband range. We explain the behavior through simulations that show in detail the plasmonic and interference effects at play.

Rivolta, N. X. A., E-mail: nicolas.rivolta@umons.ac.be; Maes, B. [Micro- and Nanophotonic Materials Group, Faculty of Science, University of Mons, Avenue Maistriau 19, B-7000 Mons (Belgium)

2014-08-07

50

Substitution of transparent conducting oxide thin films for indium tin oxide transparent electrode applications  

Microsoft Academic Search

The present status and prospects for further development of reduced or indium-free transparent conducting oxide (TCO) materials for use in practical thin-film transparent electrode applications such as liquid crystal displays are presented in this paper: reduced-indium TCO materials such as ZnO-In2O3, In2O3-SnO2 and Zn-In-Sn-O multicomponent oxides and indium-free materials such as Al- and Ga-doped ZnO (AZO and GZO). In particular,

Tadatsugu Minami

2008-01-01

51

Flexible and transparent metallic grid electrodes prepared by evaporative assembly.  

PubMed

We propose a novel approach to fabricating flexible transparent metallic grid electrodes via evaporative deposition involving flow-coating. A transparent flexible metal grid electrode was fabricated through four essential steps including: (i) polymer line pattern formation on the thermally evaporated metal layer onto a plastic substrate; (ii) rotation of the stage by 90 and the formation of the second polymer line pattern; (iii) etching of the unprotected metal region; and (iv) removal of the residual polymer from the metal grid pattern. Both the metal grid width and the spacing were systematically controlled by varying the concentration of the polymer solution and the moving distance between intermittent stop times of the polymer blade. The optimized Au grid electrodes exhibited an optical transmittance of 92% at 550 nm and a sheet resistance of 97 ?/sq. The resulting metallic grid electrodes were successfully applied to various organic electronic devices, such as organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs), and organic solar cells (OSCs). PMID:24999517

Park, Jae Hoon; Lee, Dong Yun; Kim, Young-Hoon; Kim, Jung Kyu; Lee, Jung Heon; Park, Jong Hyeok; Lee, Tae-Woo; Cho, Jeong Ho

2014-08-13

52

Low Reflectivity and High Flexibility of Tin-Doped Indium Oxide Nanofiber Transparent Electrodes  

E-print Network

in the sheet resistance. Transparent conducting oxides (TCOs) are of fundamental interest for the modernLow Reflectivity and High Flexibility of Tin-Doped Indium Oxide Nanofiber Transparent Electrodes, displays, and touch screens as a transparent electrode; however, two major problems with ITO remain: high

Cui, Yi

53

Large-scale pattern growth of graphene films for stretchable transparent electrodes  

E-print Network

of these highly conducting and transparent electrodes in flexible, stretchable, foldable electronics8,9 . GrapheneLETTERS Large-scale pattern growth of graphene films for stretchable transparent electrodes Keun transparency. At low temperatures, the monolayers transferred to silicon dioxide substrates show electron

Kim, Philip

54

Electroluminescent Device Comprising a Transparent Structured Electrode Layer Made From a Conductive Polymer  

Microsoft Academic Search

An electroluminescent (EL) device is (1) composed of polymeric LEDs comprising an active layer (7) of a conjugated polymer and a transparent polymeric electrode layer (5) having electroconductive areas (51) as electrodes. Like the active layer (7), the electrode layer (5) can be manufactured in a simple manner by spin coating. The electrode layer (5) is structured into conductive electrodes

Aemilianus G. J. Staring; David Braun

1998-01-01

55

Dye-sensitized solar cell counter electrodes based on carbon nanotubes.  

PubMed

Dye-sensitized solar cells (DSSCs) have received significant attention from the scientific community since their discovery in 1991. However, the high cost and scarcity of platinum has motivated researchers to seek other suitable materials for the counter electrode of DSSCs. Owing to their exceptional properties such as high conductivity, good electrochemical activity, and low cost, carbon nanotubes (CNTs) have been considered as promising alternatives to expensive platinum (Pt) in the counter electrode of DSSCs. Herein, we provide a Minireview of the CNTs use in the counter electrode of DSSCs. A brief overview of Pt-based counter electrodes is also discussed. Particular attention is given to the recent advances of counter electrodes with CNT-based composite structures. PMID:25367083

Hwang, Seunghwa; Batmunkh, Munkhbayar; Nine, Md J; Chung, Hanshik; Jeong, Hyomin

2015-01-12

56

Electrospray deposition of silver nanowire films for transparent electrodes.  

PubMed

Silver nanowire (AgNWs) films were fabricated as transparent electrodes by electrostatic spray deposition (ESD) at atmospheric pressure and room temperature. The effects of solution concentration, spray flow rate, applied high voltage, and annealing temperature were characterized to obtain uniform films. AgNWs thin film was produced with ca. 20 ?/[square] sheet resistance and 83% transparency in the visible range. Morphologies, optical and electrical properties, and stabilities of the films were investigated in this work. A maximum ratio of DC to optical conductivity of 288 was achieved in a 120 nm thick AgNW thin film. Chemical stability was evaluated in various solvents and we found that solvents had little effect on conductivity. PMID:22966693

Li, Jie; Cho, Sung Min; Chae, Heeyeop

2012-07-01

57

Fissile material transparency technology demonstration : neutron multiplicity counter /  

SciTech Connect

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

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

2001-01-01

58

Uniformly embedded silver nanomesh as highly bendable transparent conducting electrode  

NASA Astrophysics Data System (ADS)

Ag-nanomesh-based highly bendable conducting electrodes are developed using a combination of metal nanotransfer printing and embossing for the 6-inch wafer scale. Two Ag nanomeshes, including pitch sizes of 7.5 and 10 ?m, are used to obtain highly transparent (approximately 85% transmittance at a wavelength of 550 nm) and electrically conducting properties (below 10 ? sq?1). The Ag nanomeshes are also distinguished according to the fabrication process, which is called transferred or embedded Ag nanomesh on polyethylene terephthalate (PET) substrate, in order to compare their stability against bending stress. Then the enhancement of bending stability when the Ag nanomesh is embedded in the PET substrate is confirmed.

Choi, Hak-Jong; Choo, Soyoung; Jung, Pil-Hoon; Shin, Ju-Hyeon; Kim, Yang-Doo; Lee, Heon

2015-02-01

59

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

60

Electroluminescent Device Comprising a Transparent Structured Electrode Layer Made From a Conductive Polymer  

Microsoft Academic Search

A description is given of an electroluminescent (EL) device (1) composed of polymeric LEDs comprising an active layer (7) of a conjugated polymer and a transparent polymeric electrode layer (5) having electroconductive areas (51) as electrodes. Like the active layer (7), the electrode layer (5) can be manufactured in a simple manner by spin coating. The electrode layer (5) is

Aemilianus G. J. Staring; David Braun

1999-01-01

61

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

PubMed Central

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. PMID:20672135

2010-01-01

62

Effects of counter electrodes on photovoltaic performance of all-solid-state TiO2-based dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

In order to analyse the effects of counter electrodes on photovoltaic performance of dye-sensitized solar cells (DSSCs), different electrodes were used as the counter electrodes for all-solid-state TiO2-based DSSCs. An inorganic solid-state electrolyte, CsSnI2.95F0.05, was selected to couple with N719 dye-sensitized TiO2 nanorod arrays to fabricate the DSSCs. Fluorine doped tin oxide transparent conducting glass (FTO), platinum coated FTO (Pt/FTO), graphite coated FTO (graphite/FTO), and graphite coated common glass (graphite/glass) were investigated as the counter electrodes, and the cells composed of the corresponding electrodes above have power-conversion efficiencies of 2.17%, 9.84%, 7.62%, and 3.45%, respectively. Our findings indicate that due to its unique catalytic and conducting properties, graphite can replace both Pt and FTO as a counter electrode to reduce the fabrication cost of all-solid-state TiO2-based DSSCs.

Shang, Mingwei; Liu, Benjamin; Dong, Zhenhua; Dong, Zhenyu; Dong, Lifeng

2015-03-01

63

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

64

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

65

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

E-print Network

Dye-sensitized solar cell with a titanium-oxide-modified carbon nanotube transparent electrode A. K 2011; published online 15 July 2011) Transparent and conductive carbon-based materials are promising reaction limits their application as a working electrode in a liquid-type dye-sensitized solar cell (DSSC

Demir, Hilmi Volkan

66

Uniformly embedded silver nanomesh as highly bendable transparent conducting electrode.  

PubMed

Ag-nanomesh-based highly bendable conducting electrodes are developed using a combination of metal nanotransfer printing and embossing for the 6-inch wafer scale. Two Ag nanomeshes, including pitch sizes of 7.5 and 10 ?m, are used to obtain highly transparent (approximately 85% transmittance at a wavelength of 550 nm) and electrically conducting properties (below 10 ? sq(-1)). The Ag nanomeshes are also distinguished according to the fabrication process, which is called transferred or embedded Ag nanomesh on polyethylene terephthalate (PET) substrate, in order to compare their stability against bending stress. Then the enhancement of bending stability when the Ag nanomesh is embedded in the PET substrate is confirmed. PMID:25590555

Choi, Hak-Jong; Choo, Soyoung; Jung, Pil-Hoon; Shin, Ju-Hyeon; Kim, Yang-Doo; Lee, Heon

2015-02-01

67

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

68

Graphene nanosheet counter-electrodes for dye-sensitized solar cells  

Microsoft Academic Search

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

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

2010-01-01

69

Polycarbazole nanocomposites with conducting metal oxides for transparent electrode applications.  

PubMed

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

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

2010-02-01

70

Quasi-solid-state dye-sensitized solar cells: Pt and PEDOT:PSS counter electrodes applied to gel electrolyte assemblies  

Microsoft Academic Search

In this paper we present an attempt to substitute liquid electrolyte (LC) dye-sensitized solar cells (DSSCs) by quasi-solid-state constructions (SC) for semi-transparency application adopting organic\\/inorganic gels in combination with standard (Pt based) and alternative (PEDOT:PSS based) counter electrodes. Gel polymer electrolytes are prepared by incorporating a liquid electrolyte into a polymer matrix such as polymethyl-methacrylate (PMMA) using propylene carbonate (PC)

Matteo Biancardo; Keld West; Frederik C. Krebs

2007-01-01

71

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

72

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

73

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

74

Conducting polymers based counter electrodes for dye-sensitized solar cells  

SciTech Connect

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

Veerender, P., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Saxena, Vibha, E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Gusain, Abhay, E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Jha, P., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Koiry, S. P., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Chauhan, A. K., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Aswal, D. K., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Gupta, S. K., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai - 400085 (India)

2014-04-24

75

Conducting polymers based counter electrodes for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

76

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

77

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

78

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

NASA Astrophysics Data System (ADS)

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

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

1991-03-01

79

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

80

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

81

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

PubMed

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

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

2012-01-01

82

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

PubMed Central

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

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

2013-01-01

83

Transparent Aluminum Nanomesh Electrode Fabricated by Nanopatterning Using Self-Assembled Nanoparticles  

Microsoft Academic Search

A novel transparent aluminum nanomesh electrode with nanoapartures smaller than the wavelength of the light was proposed. Unlike conventional conducting oxides such as indium tin oxide, it has the potential to realize a rare-metal-free and low-resistivity transparent electrode. It was fabricated by nanopatterning with our embedded particle monolayer method, which enables the formation of a self-assembled particle monolayer over a

Tsutomu Nakanishi; Eishi Tsutsumi; Kumi Masunaga; Akira Fujimoto; Koji Asakawa

2011-01-01

84

Transparent flexible organic thin-film transistors that use printed single-walled carbon nanotube electrodes  

E-print Network

Transparent flexible organic thin-film transistors that use printed single-walled carbon nanotube; published online 15 March 2006 Electrodes based on printed networks of single-walled carbon nanotubes SWNTs are integrated with ultrathin layers of the organic semiconductor pentacene to produce bendable, transparent thin

Rogers, John A.

85

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

86

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

87

A novel carbon-PEDOT composite counter electrode for monolithic dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

The development of a new counter electrode structure for monolithic dye-sensitized solar cells (DSCs) is reported. A conducting polymer, PEDOT, is selectively electrodeposited throughout the carbon layer of the counter electrode, as confirmed by SEM. The formation of this composite allows reduced electrical resistivity, thus improving the fill factor and efficiency of devices. The improved mechanical stability of the carbon/conducting polymer composite layers makes these more suitable for use with flexible substrates, which is advantageous for the development of monolithic DSCs on plastic substrates that can be produced using roll-to-roll processes.

Thompson, Simon J.; Pringle, Jennifer M.; Li Zhang, Xiao; Cheng, Yi-Bing

2013-01-01

88

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

89

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

90

Bifacial dye-sensitized solar cells from covalent-bonded polyaniline-multiwalled carbon nanotube complex counter electrodes  

NASA Astrophysics Data System (ADS)

Exploration of cost-effective counter electrodes (CEs) and enhancement of power conversion efficiency have been two persistent objectives for dye-sensitized solar cells (DSSCs). In the current work, polyaniline-multiwalled carbon nanotube (PANi-MWCNT) complexes are synthesized by a reflux method and employed as CE materials for bifacial DSSCs. Owing to the high optical transparency of PANi-MWCNT complex CE, the incident light from rear side can compensate for the incident light from TiO2 anode. The charge-transfer ability and electrochemical behaviors demonstrate the potential utilization of PANi-MWCNT complex CEs in robust bifacial DSSCs. The electrochemical properties as well as photovoltaic performances are optimized by adjusting MWCNT dosages. A maximum power conversion efficiency of 9.24% is recorded from the bifacial DSSC employing PANi-8wt MWCNT complex CE for both irradiation, which is better than 8.08% from pure PANi CE.

Zhang, Huihui; He, Benlin; Tang, Qunwei; Yu, Liangmin

2015-02-01

91

Improved durability of dye-sensitized solar cell with H2-reduced carbon counter electrode  

NASA Astrophysics Data System (ADS)

Carbon counter electrodes for dye-sensitized solar cells (DSSCs) have attracted strong attention due to their low material cost and practically high power conversion efficiency (PCE). However, there were issues in PCE stability observed during durability tests. In this study, H2-reduced carbon counter electrode for low cost DSSCs is introduced and demonstrated improved durability over the conventional carbon electrodes, with the absolute PCE value of 7.7%. It was found that carbon resistance decay ratio improved compared to those without H2-reduction process. These cells after the durability test were disassembled, and surface adsorptions on the carbon counter electrodes were analyzed. The adsorption of compounds originated from the dye and co-adsorbents on the H2-reduced carbon electrode was largely reduced, due to the cleaning of surface functional groups that can adsorb large molecules. These results suggest that H2-reduction process proposed in this work effectively reduces surface adsorptions on carbon electrode, and as a result improves the durability of DSSCs.

Takada, Harumi; Obana, Yoshiaki; Sasaki, Ryo; Kuribayashi, Miki; Kanno, Masato; Zhu, Cheng; Bessho, Takeru; Takagi, Yuto; Hinokuma, Koichiro; Noda, Kazuhiro

2015-01-01

92

Dye sensitized solar cells with a plastic counter electrode of poly(3,4-ethylene dioxythiophene)-poly(styrenesulfonate)  

Microsoft Academic Search

We report on dye sensitized solar cells with PEDOT-PSS coated directly on flexible polyester substrate as counter electrode. The behavior of such plastic counter electrode in the presence of I - \\/I3 redox electrolyte has been investigated with X-ray photoelectron spectroscopy. We have found that some of iodine species are \\

Anna Kanciurzewska; Ewa Dobruchowska; Amir Baranzahi; Elin Carlegrim; Ana Fahlman; Mats Fahlman; Mihai A. Grtu

2007-01-01

93

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

94

Transparent, Flexible, Low Noise Graphene Electrodes for Simultaneous Electrophysiology and Neuroimaging  

PubMed Central

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, due to 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 artifacts in the electrical recordings. Graphene electrodes record high frequency bursting activity and slow synaptic potentials that are hard to resolve by multi-cellular calcium imaging. This transparent electrode technology may pave the way for high spatio-temporal resolution electrooptic 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

95

Reference and Counter Electrode Positions Affect Electrochemical Characterization of Bioanodes in  

E-print Network

characterization using CVs and EIS due to negligible ohmic resistances (0.4 V). It is therefore concludedReference and Counter Electrode Positions Affect Electrochemical Characterization of Bioanodes spectra (EIS) also changed with RE distances, resulting in a calculated increase in anode resistance

96

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

97

Inverse opal carbons for counter electrode of dye-sensitized solar cells.  

PubMed

We investigated the fabrication of inverse opal carbon counter electrodes using a colloidal templating method for DSSCs. Specifically, bare inverse opal carbon, mesopore-incoporated inverse opal carbon, and graphitized inverse opal carbon were synthesized and stably dispersed in ethanol solution for spray coating on a FTO substrate. The thickness of the electrode was controlled by the number of coatings, and the average relative thickness was evaluated by measuring the transmittance spectrum. The effect of the counter electrode thickness on the photovoltaic performance of the DSSCs was investigated and analyzed by interfacial charge transfer resistance (R(CT)) under EIS measurement. The effect of the surface area and conductivity of the inverse opal was also investigated by considering the increase in surface area due to the mesopore in the inverse opal carbon and conductivity by graphitization of the carbon matrix. The results showed that the FF and thereby the efficiency of DSSCs were increased as the electrode thickness increased. Consequently, the larger FF and thereby the greater efficiency of the DSSCs were achieved for mIOC and gIOC compared to IOC, which was attributed to the lower R(CT). Finally, compared to a conventional Pt counter electrode, the inverse opal-based carbon showed a comparable efficiency upon application to DSSCs. PMID:22475456

Kang, Da-Young; Lee, Youngshin; Cho, Chang-Yeol; Moon, Jun Hyuk

2012-05-01

98

Large-scale plasma patterning of transparent graphene electrode on flexible substrates.  

PubMed

Graphene, a two-dimensional carbon material, has attracted significant interest for applications in flexible electronics as an alternative transparent electrode to indium tin oxide. However, it still remains a challenge to develop a simple, reproducible, and controllable fabrication technique for producing homogeneous large-scale graphene films and creating uniform patterns with desired shapes at defined positions. Here, we present a simple route to scalable fabrication of flexible transparent graphene electrodes using an oxygen plasma etching technique in a capacitively coupled plasma (CCP) system. Ascorbic acid-assisted chemical reduction enables the large-scale production of graphene with solution-based processability. Oxygen plasma in the CCP system facilitates the reproducible patterning of graphene electrodes, which allows controllable feature sizes and shapes on flexible plastic substrates. The resulting graphene electrode exhibits a high conductivity of 80 S cm(-1) and a transparency of 76% and retains excellent flexibility upon hard bending at an angle of 175 and after repeated bending cycles. A simple LED circuit integrated on the patterned graphene film demonstrates the feasibility of graphene electrodes for use in flexible transparent electrodes. PMID:25692852

Kim, Ji Hye; Ko, Euna; Hwang, Joonki; Pham, Xuan-Hung; Lee, Joo Heon; Lee, Sung Hwan; Tran, Van-Khue; Kim, Jong-Ho; Park, Jin-Goo; Choo, Jaebum; Han, Kwi Nam; Seong, Gi Hun

2015-03-10

99

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

100

Transparent and transferrable organic optoelectronic devices based on WO3/Ag/WO3 electrodes  

NASA Astrophysics Data System (ADS)

With a thin metal film inserted between two oxide layers, the WO3/Ag/WO3 (WAW) multilayer structure owns both high transmittance and high conductivity. By carefully optimizing Ag film thickness, WAW shows high average transmittance of 82.5% in 400-750 nm range and low sheet resistance of 20 ?/sq. Employing such WAW electrodes, transparent organic photodetectors are fabricated, and with help of a polyacrylonitrile protective layer, the devices can be smartly separated and transferred onto other substrates while maintaining their performances well. Moreover, transferrable organic solar cells are also realized with such transparent WAW electrodes.

Qi, Zhe; Cao, Jiamin; Ding, Liming; Wang, Jizheng

2015-02-01

101

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

DOEpatents

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

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

2008-01-08

102

ZnO:H indium-free transparent conductive electrodes for active-matrix display applications  

NASA Astrophysics Data System (ADS)

Transparent conductive electrodes based on hydrogen (H)-doped zinc oxide (ZnO) have been proposed for active-matrix (AM) display applications. When fabricated with optimal H plasma power and optimal plasma treatment time, the resulting ZnO:H films exhibit low sheet resistance of 200 ?/? and high average transmission of 85% at a film thickness of 150 nm. The demonstrated transparent conductive ZnO:H films can potentially replace indium-tin-oxide and serve as pixel electrodes for organic light-emitting diodes as well as source/drain electrodes for ZnO-based thin-film transistors. Use of the proposed ZnO:H electrodes means that two photomask stages can be removed from the fabrication process flow for ZnO-based AM backplanes.

Chen, Shuming; Wang, Sisi

2014-12-01

103

Transparent conducting electrodes based on thin, ultra-long copper nanowires and graphene nano-composites  

NASA Astrophysics Data System (ADS)

High aspect-ratio ultra-long (> 70 ?m) and thin (< 50 nm) copper nanowires (Cu-NW) were synthesized in large quantities using a solution-based approach. The nanowires, along with reduced graphene-oxide sheets, were coated onto glass as well as plastic substrates, thus producing transparent conducting electrodes. Our fabricated transparent electrodes achieved high optical transmittance and low sheet resistance, comparable to those of existing Indium Tin Oxide (ITO) electrodes. Furthermore, our electrodes show no notable loss of performance under high temperature and high humidity conditions. Adaptations of such nano-materials into smooth and ultrathin films lead to potential alternatives for the conventional tin-doped indium oxide, with applications in a wide range of solar cells, flexible displays, and other opto-electronic devices.

Zhu, Zhaozhao; Mankowski, Trent S.; Balakrishnan, Kaushik; Shikoh, Ali Sehpar; Touati, Farid; Benammar, Mohieddine A.; Mansuripur, Masud; Falco, Charles M.

2014-10-01

104

Screen printed, transparent, and flexible electrodes based on graphene nanoplatelet pastes  

NASA Astrophysics Data System (ADS)

Transparent, flexible and conducting graphene films were produced by screen printing method using printing pastes based on graphene nanoplatelets in polymer matrix. The transparency of received layers and the mechanical resistivity in several bending cycles were measured. Subsequently percolation threshold was investigated. Graphene layers were printed on diverse substrates (glass, Al2O3, PET) and afterwards for samples printed on glass different firing atmospheres (N2, H2, air) were studied. Best firing results (resistance decrease) were obtained for treatment in 250 C in atmosphere of air. Finally investigation results were used to produce a transparent and elastic electrode for an electroluminescent display, showing the application potential of our graphene nanocomposite pastes.

Wrblewski, Grzegorz; Janczak, Daniel

105

Scalable low-cost SnS(2) nanosheets as counter electrode building blocks for dye-sensitized solar cells.  

PubMed

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

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

2014-07-01

106

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

107

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

108

Transparent electrode requirements for thin film solar cell modules Michael W. Rowell and Michael D. McGehee*  

E-print Network

transparent conducting oxides (TCO),2 such as indium tin oxide (ITO) or doped zinc oxide (ZnO), are used owingTransparent electrode requirements for thin film solar cell modules Michael W. Rowell and Michael D The transparent conductor (TC) layer in thin film solar cell modules has a significant impact on the power

McGehee, Michael

109

Single-layer graphene as a stable and transparent electrode for nonaqueous radical annihilation electrogenerated chemiluminescence.  

PubMed

We explored the use of single-layer graphene (SLG) obtained by chemical vapor deposition, and transferred to a glass substrate, as a transparent electrode material for use in coupled electrochemical and spectroscopic experiments in nonaqueous media through electrogenerated chemiluminescence (ECL). SLG was used with classical ECL luminophores, rubrene and 9,10-diphenylanthracene, in an inert environment to generate stable electrochemical responses and measure light emission through it. As an electrode material, SLG displayed excellent stability during electrochemical potential stepping and voltammetry in a window that spanned at least from ca. -2.4 to +1.8 V versus SCE in acetonitrile and acetonitrile/benzene. Although the peak splitting between forward and reverse sweeps in voltammetry was larger in comparison to metal electrodes due to in-plane resistance, SLG displayed sufficiently facile electron transfer properties to yield stable voltammetric cycling and ECL. SLG electrodes patterned with poly tetrafluoroethylene permitted the stable generation of radical ions on an SLG microelectrode to be studied through scanning electrochemical microscopy in the generation/collection mode. SLG was able to stably collect radical ions produced by a 50 ?m gold tip with up to 96% collection efficiency. The transparency of graphene was used to obtain accurate spectral responses in ECL. While inner filter effects are known to cause a shift in peak emission wavelength of spectroelectrochemical studies, the use of SLG electrodes with detection through the graphene window reduced apparent peak shifts by up to 10 nm in peak wavelength. This work introduces SLG as a virtually transparent, electrochemically active, and chemically stable platform for studying ECL in the radical annihilation mode, where large electrode polarizations could compromise the chemical stability of other existing transparent electrodes. PMID:25780938

Cristarella, Teresa C; Chinderle, Adam J; Hui, Jingshu; Rodrguez-Lpez, Joaqun

2015-04-01

110

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

Microsoft Academic Search

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

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

2010-01-01

111

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

112

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

113

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

114

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

PubMed

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

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

2012-09-01

115

Electrochemical sensor having suspended element counter electrode and deflection method for current sensing  

DOEpatents

An electrochemical suspended element-based sensor system includes a solution cell for holding an electrolyte comprising solution including at least one electrochemically reducible or oxidizable species. A working electrode (WE), reference electrode (RE) and a counter electrode (CE) are disposed in the solution. The CE includes an asymmetric suspended element, wherein one side of the suspended element includes a metal or a highly doped semiconductor surface. The suspended element bends when current associated with reduction or oxidation of the electrochemically reducible or oxidizable species at the WE passes through the suspended element. At least one measurement system measures the bending of the suspended element or a parameter which is a function of the bending.

Thundat, Thomas G.; Brown, Gilbert M.

2010-05-18

116

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

117

A high-performance counter electrode based on poly(3,4-alkylenedioxythiophene) for dye-sensitized solar cells  

Microsoft Academic Search

A poly(3,3-diethyl-3,4-dihydro-2H-thieno-[3,4-b][1,4]dioxepine) (PProDOT-Et2) counter electrode prepared by electrochemical polymerization on a fluorine-doped tin oxide (FTO) glass substrate was incorporated in a platinum-free dye-sensitized solar cell (DSSC). The surface roughness and I?\\/I3? redox reaction behaviors based on PProDOT-Et2, poly(3,4-propylenedioxythiophene) (PProDOT), poly(3,4-ethylenedioxythiophene) (PEDOT), and sputtered-Pt electrodes were characterized, and their performances as counter electrodes in DSSCs were compared. Cells fabricated with a

Kun-Mu Lee; Po-Yen Chen; Chih-Yu Hsu; Jen-Hsien Huang; Wen-Hsien Ho; Hung-Chang Chen; Kuo-Chuan Ho

2009-01-01

118

Effects of mesoscopic poly(3,4-ethylenedioxythiophene) films as counter electrodes for dye-sensitized solar cells  

Microsoft Academic Search

Counter electrode coated with chemically polymerized poly(3,4-ethylenedioxythiophene) (PEDOT) in a dye-sensitized solar cell (DSSC) was studied. The surface morphology and the nature of I?\\/I3? redox reaction based on PEDOT film were investigated using Atomic Force Microscopy and Cyclic Voltammetry, respectively. The performance of the DSSCs containing the PEDOT coated electrode was compared with sputtered-Pt electrode. We found that the root

Kun-Mu Lee; Wei-Hao Chiu; Hung-Yu Wei; Chih-Wei Hu; Vembu Suryanarayanan; Weng-Feng Hsieh; Kuo-Chuan Ho

2010-01-01

119

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

Microsoft Academic Search

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

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

2010-01-01

120

Planar silver nanowire, carbon nanotube and PEDOT:PSS nanocomposite transparent electrodes  

NASA Astrophysics Data System (ADS)

Highly conductive, transparent and flexible planar electrodes were fabricated using interwoven silver nanowires and single-walled carbon nanotubes (AgNW:SWCNT) in a PEDOT:PSS matrix via an epoxy transfer method from a silicon template. The planar electrodes achieved a sheet resistance of 6.6 0.0 ?/? and an average transmission of 86% between 400 and 800 nm. A high figure of merit of 367 ??1 is reported for the electrodes, which is much higher than that measured for indium tin oxide and reported for other AgNW composites. The AgNW:SWCNT:PEDOT:PSS electrode was used to fabricate low temperature (annealing free) devices demonstrating their potential to function with a range of organic semiconducting polymer:fullerene bulk heterojunction blend systems.

Stapleton, Andrew J.; Yambem, Soniya D.; Johns, Ashley H.; Afre, Rakesh A.; Ellis, Amanda V.; Shapter, Joe G.; Andersson, Gunther G.; Quinton, Jamie S.; Burn, Paul L.; Meredith, Paul; Lewis, David A.

2015-04-01

121

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

122

Inkjet printed silver nanowire network as top electrode for semi-transparent organic photovoltaic devices  

NASA Astrophysics Data System (ADS)

A method for direct inkjet printing of silver nanowire (Ag NW) to form transparent conductive network as the top electrode for inverted semi-transparent organic photovoltaic devices (OPV) was developed. The highest power conversion efficiency of the poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PC61BM) based OPV was achieved to be 2.71% when the top electrode was formed by 7 times of printing. In general, devices with printed Ag NW top electrode had similar open-circuit voltage (VOC, around 0.60 V) but lower fill factor (FF, 0.33-0.54) than that of device with thermally deposited Ag opaque electrode (reference device). Both FF and short-circuit current density (JSC), however, were found to be increasing with the increase of printing times (3, 5, and 7), which could be partially attributed to the improved conductivity of Ag NW network electrodes. The solvent effect on device performances was studied carefully by comparing the current density-voltage (J-V) curves of different devices. The results revealed that solvent treatment on the anode buffer layer during printing led to a decrease of charge injection selectivity and an increase of charge recombination at the anode interface, which was considered to be the reason for the degrading of device performance.

Lu, Hui; Lin, Jian; Wu, Na; Nie, Shuhong; Luo, Qun; Ma, Chang-Qi; Cui, Zheng

2015-03-01

123

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

124

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

SciTech Connect

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, E-mail: imdlhkkim@khu.ac.kr [Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, 1 Seocheon-dong, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of)

2014-02-17

125

Transparent flexible organic thin-film transistors that use printed single-walled carbon nanotube electrodes  

Microsoft Academic Search

Electrodes based on printed networks of single-walled carbon nanotubes (SWNTs) are integrated with ultrathin layers of the organic semiconductor pentacene to produce bendable, transparent thin-film transistors on plastic substrates. The physical and structural properties of the SWNTs lead to the remarkably good electrical contacts with the pentacene. Optical transmittances of ~70%, device mobilities >0.5 cm2 V-1 s-1, ON\\/OFF ratios >105

Qing Cao; Zheng-Tao Zhu; Maxime G. Lemaitre; Ming-Gang Xia; Moonsub Shim; John A. Rogers

2006-01-01

126

Fabrication and characterization of cuprous oxide solar cell with net-shaped counter electrode  

NASA Astrophysics Data System (ADS)

In this work, simple solar cells using cuprous oxide were fabricated and characterized. The solar cells in this experiment used cuprous oxide plate as detecting electrode and copper wires which were woven into a net-shape with a gap size of 2 x 2 cm as a counter electrode. Twenty samples of solar cells were fabricated with oxide layer which were thermally grown in temperature up to 550 oC. Samples with variations in oxidation time (15 minutes, 30 minutes, 40 minutes, and 45 minutes) and distance between electrodes (2 cm, 3 cm, and 4 cm) with an electrolyte solution of NaCl with molarity of 2.188 mol/l were produced. The samples were characterized by measuring their V-I curve. For this purpose, a simple, own-made solar simulator were fabricated and characterized. Using curve fitting technique, parameters such as FF (Fill Factor), efficiency, open circuit voltage, short circuit current, internal resistance, and performance degradation as a function of time of the cells were extracted. The result shows optimum efficiency of 4.573. 10-4%, while optimum oxidation time is 40 minutes and optimum distance between electrodes is 3 cm.

Basuki, Stefanus; Uranus, Henri P.; Pangaribuan, Julinda

2015-01-01

127

Highly transparent Nb-doped indium oxide electrodes for organic solar cells  

SciTech Connect

The authors investigated the characteristics of Nb-doped In{sub 2}O{sub 3} (INbO) films prepared by co-sputtering of Nb{sub 2}O{sub 5} and In{sub 2}O{sub 3} for use in transparent anodes for organic solar cells (OSCs). To optimize the Nb dopant composition in the In{sub 2}O{sub 3} matrix, the effect of the Nb doping power on the resistivity and transparency of the INbO films were examined. The electronic structure and microstructure of the INbO films were also investigated using synchrotron x-ray absorption spectroscopy and x-ray diffraction examinations in detail. At the optimized Nb co-sputtering power of 30?W, the INbO film exhibited a sheet resistance of 15??/sq, and an optical transmittance of 86.04% at 550?nm, which are highly acceptable for the use as transparent electrodes in the fabrication of OSCs. More importantly, the comparable power conversion efficiency (3.34%) of the OSC with an INbO anode with that (3.31%) of an OSC with a commercial ITO anode indicates that INbO films are promising as a transparent electrode for high performance OSCs.

Kim, Jun Ho; Seong, Tae-Yeon [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Na, Seok-In [Professional Graduate School of Flexible and Printable Electronics, Chonbuk National University, 664-14, Deokjin-dong, Jeongju-si, Jellabuk-do 561-756 (Korea, Republic of); Chung, Kwun-Bum [Department of Physics, Dankook University, Mt. 29, Anseo-Dong, Chenan 330-714 (Korea, Republic of); Lee, Hye-Min; Kim, Han-Ki, E-mail: imdlhkkim@khu.ac.kr [Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, 1 Seocheon-dong, Yongin, Gyeonggi-do 446-701 (Korea, Republic of)

2014-03-15

128

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

129

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

130

Mechanical flexibility of transparent PEDOT:PSS electrodes prepared by gravure printing for flexible organic solar cells  

Microsoft Academic Search

The mechanical flexibility of transparent poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films printed onto a flexible PET substrate using a gravure printing method was investigated using a lab-made bending test system. Gravure-printed PEDOT:PSS electrodes with a sheet resistance of 359?\\/square and a transparency of 88.92% showed outstanding flexibility in several types of flexibility tests, including outer\\/inner bending, twisting and stretching. Notably, the PEDOT:PSS electrode

Chung-Ki Cho; Woo-Jin Hwang; Kyoungtae Eun; Sung-Hoon Choa; Seok-In Na; Han-Ki Kim

2011-01-01

131

Indium Tin Oxide-Free Transparent Conductive Electrode for GaN-Based Ultraviolet Light-Emitting Diodes.  

PubMed

Transparent conducting electrodes are important components of highly efficient ultraviolet light-emitting diodes (UV LEDs). Indium tin oxide (ITO) is commonly used to form a current spreading layer, but its UV-range optical transparency is limited with a low sheet resistance. We demonstrate a simple solution-based coating technique to obtain large-area, highly uniform, and conductive silver-nanowire-based electrodes that exhibit UV-range optical transparency better than that of ITO for the same sheet resistance. The UV LEDs fabricated using this current spreading layer showed improved optical power emission as well as improvement in electrical properties. PMID:25830932

Kim, Ja-Yeon; Jeon, Jong-Hyun; Kwon, Min-Ki

2015-04-22

132

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

133

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

NASA Astrophysics Data System (ADS)

The outstanding electrical, mechanical and chemical properties of graphene make it attractive for applications in flexible electronics. However, efforts to make transparent conducting films from graphene have been hampered by the lack of efficient methods for the synthesis, transfer and doping of graphene at the scale and quality required for applications. Here, we report the roll-to-roll production and wet-chemical doping of predominantly monolayer 30-inch graphene films grown by chemical vapour deposition onto flexible copper substrates. The films have sheet resistances as low as ~125 ? ?-1 with 97.4% optical transmittance, and exhibit the half-integer quantum Hall effect, indicating their high quality. We further use layer-by-layer stacking to fabricate a doped four-layer film and measure its sheet resistance at values as low as ~30 ? ?-1 at ~90% transparency, which is superior to commercial transparent electrodes such as indium tin oxides. Graphene electrodes were incorporated into a fully functional touch-screen panel device capable of withstanding high strain.

Bae, Sukang; Kim, Hyeongkeun; Lee, Youngbin; Xu, Xiangfan; Park, Jae-Sung; Zheng, Yi; Balakrishnan, Jayakumar; Lei, Tian; Ri Kim, Hye; Song, Young Il; Kim, Young-Jin; Kim, Kwang S.; zyilmaz, Barbaros; Ahn, Jong-Hyun; Hong, Byung Hee; Iijima, Sumio

2010-08-01

134

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

NASA Astrophysics Data System (ADS)

The outstanding electrical1, mechanical and chemical properties of graphene make it attractive for applications in flexible electronics. However, efforts to make transparent conducting films from graphene have been hampered by the lack of efficient methods for the synthesis, transfer and doping of graphene at the scale and quality required for applications. Here, we report the roll-to-roll production and wet-chemical doping of predominantly monolayer 30-inch graphene films grown by chemical vapour deposition onto flexible copper substrates. The films have sheet resistances as low as 125 Ohm/sq with 97.4% optical transmittance, and exhibit the half-integer quantum Hall effect, indicating their high quality. We further use layer-by-layer stacking to fabricate a doped four-layer film and measure its sheet resistance at values as low as 30 Ohm/sq at 90% transparency, which is superior to commercial transparent electrodes such as indium tin oxides. Graphene electrodes were incorporated into a fully functional touch-screen panel device capable of withstanding high strain.

Hong, Byung Hee

2011-03-01

135

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

PubMed

The outstanding electrical, mechanical and chemical properties of graphene make it attractive for applications in flexible electronics. However, efforts to make transparent conducting films from graphene have been hampered by the lack of efficient methods for the synthesis, transfer and doping of graphene at the scale and quality required for applications. Here, we report the roll-to-roll production and wet-chemical doping of predominantly monolayer 30-inch graphene films grown by chemical vapour deposition onto flexible copper substrates. The films have sheet resistances as low as approximately 125 ohms square(-1) with 97.4% optical transmittance, and exhibit the half-integer quantum Hall effect, indicating their high quality. We further use layer-by-layer stacking to fabricate a doped four-layer film and measure its sheet resistance at values as low as approximately 30 ohms square(-1) at approximately 90% transparency, which is superior to commercial transparent electrodes such as indium tin oxides. Graphene electrodes were incorporated into a fully functional touch-screen panel device capable of withstanding high strain. PMID:20562870

Bae, Sukang; Kim, Hyeongkeun; Lee, Youngbin; Xu, Xiangfan; Park, Jae-Sung; Zheng, Yi; Balakrishnan, Jayakumar; Lei, Tian; Kim, Hye Ri; Song, Young Il; Kim, Young-Jin; Kim, Kwang S; Ozyilmaz, Barbaros; Ahn, Jong-Hyun; Hong, Byung Hee; Iijima, Sumio

2010-08-01

136

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

137

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

PubMed

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its clean, low-cost, high efficiency, good durability, and easy fabrication. However, enhancing the efficiency of the DSSC still is an important issue. Here we devise a bifacial DSSC based on a transparent polyaniline (PANI) counter electrode (CE). Owing to the sunlight irradiation simultaneously from the front and the rear sides, more dye molecules are excited and more carriers are generated, which results in the enhancement of short-circuit current density and therefore overall conversion efficiency. The photoelectric properties of PANI can be improved by modifying with 4-aminothiophenol (4-ATP). The bifacial DSSC with 4-ATP/PANI CE achieves a light-to-electric energy conversion efficiency of 8.35%, which is increased by ~24.6% compared to the DSSC irradiated from the front only. This new concept along with promising results provides a new approach for enhancing the photovoltaic performances of solar cells. PMID:24504117

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

2014-01-01

138

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

PubMed

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

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

2014-06-21

139

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

140

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

141

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

142

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

PubMed

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

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

2013-09-01

143

Transparent and flexible supercapacitors with single walled carbon nanotube thin film electrodes.  

PubMed

We describe a simple process for the fabrication of transparent and flexible, solid-state supercapacitors. Symmetric electrodes made up of binder-free single walled carbon nanotube (SWCNT) thin films were deposited onto polydimethylsiloxane substrates by vacuum filtration followed by a stamping method, and solid-state supercapacitor devices were assembled using a gel electrolyte. An optical transmittance of 82% was found for 0.02 mg of SWCNTs, and a specific capacitance of 22.2 F/g was obtained. The power density can reach to 41.5 kW kg(-1) and shows good capacity retention (94%) upon cycling over 500 times. Fabricated supercapacitors will be relevant for the realization of transparent and flexible devices with energy storage capabilities, displays and touch screens in particular. PMID:25127070

Yuksel, Recep; Sarioba, Zeynep; Cirpan, Ali; Hiralal, Pritesh; Unalan, Husnu Emrah

2014-09-10

144

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

145

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

146

Dye sensitized solar cells with a plastic counter electrode of poly(3,4-ethylene dioxythiophene)-poly(styrenesulfonate)  

NASA Astrophysics Data System (ADS)

We report on dye sensitized solar cells with PEDOT-PSS coated directly on flexible polyester substrate as counter electrode. The behavior of such plastic counter electrode in the presence of I - /I 3 redox electrolyte has been investigated with X-ray photoelectron spectroscopy. We have found that some of iodine species are "trapped" within the PEDOT-PSS layer. The presence of I 3 - , I II and PEDOT charge transfer complexes with iodine species may block the surface of the electrode. Furthermore, the PEDOT may be further oxidized (p-doped) during cell operation, which in turn may cause over oxidation and loss of conductivity in the PEDOT-PSS film. The interactions between PEDOT and iodine species may be enlarged because of the partial loss of PSS protective counter ion. The result is a decrease of PEDOT-PSS catalytic activity for reduction of I 3 - to I - in the redox electrolyte and worse cell performance than in the case of DSSC with Pt counter electrode.

Kanciurzewska, Anna; Dobruchowska, Ewa; Baranzahi, Amir; Carlegrim, Elin; Fahlman, Ana; Fahlman, Mats; Gr?u, Mihai A.

2007-09-01

147

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

148

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

PubMed Central

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

2014-01-01

149

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

150

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. PMID:24729040

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

2014-10-01

151

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

152

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

153

N-doped graphene nanoribbons as efficient metal-free counter electrodes for disulfide/thiolate redox mediated DSSCs.  

PubMed

Nitrogen-doped graphene nanoribbons (N-GNRs) were prepared by thermal treatment of the as-zipped graphene oxide nanoribbons in NH3 gas. X-ray photoelectron spectroscopy (XPS) measurements revealed a high nitrogen content up to 6.5 atom% for the as-prepared N-GNRs. This, together with the high Brunauer-Emmett-Teller (BET) surface area of about 751 cm(2) g(-1), prompted us to use the N-GNR as the first low-cost, metal-free counter electrode for disulfide/thiolate redox mediated dye-sensitized solar cells (DSSCs). Compared with the widely-used platinum electrode, the newly-developed N-GNR counter electrode showed a dramatically improved power conversion efficiency for DSSCs based on the thiolate/disulfide redox shuttle. The observed superior cell performance was attributed to the enhanced charge transfer capability and electrocatalytic activity induced by N-doping of the graphene nanoribbon. PMID:25611156

Xue, Yuhua; Baek, Janice M; Chen, Hao; Qu, Jia; Dai, Liming

2015-04-01

154

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

155

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

156

High performance ZnO-SnO?:F nanocomposite transparent electrodes for energy applications.  

PubMed

Enhancing the propagation length of light without sacrificing the electro-optical properties of transparent electrodes is of particular interest to solar cells for reaching higher efficiency. This can typically be achieved by nanostructured electrodes but all too often at the expense of complexity and cost-effectiveness. In this work, we demonstrate the simple and low-cost fabrication of a new type of ZnO-SnO2:F nanocomposite thin film by combining spin-coated ZnO nanoparticles on glass with fluorine-doped SnO2 thin films deposited by atmospheric spray pyrolysis. The resulting nanocomposites exhibit a dual surface morphology featuring rough ZnO-SnO2:F nanostructures along with the original smooth SnO2:F thin film. By readily modulating the surface morphology of ZnO-SnO2:F nanocomposite thin films with the initial ZnO NP surface coverage, the scattering efficiency of the incident light can remarkably be controlled over the 400-1100 nm solar spectrum wavelength range. High quality hazy ZnO-SnO2:F thin layers are therefore formed with an averaged haze factor ranging from 0.4 to 64.2% over the 400-1100 nm solar spectrum range while the sheet resistance is kept smaller than 15 ?/sq for an average total optical transmittance close to 80%, substrate absorption and reflection included. Eventually, optical simulations using Fourier transform techniques are performed for computing the obtained haze factors and show good agreement with experimental data in the 400-1100 nm solar spectrum wavelength range. This opens up additional opportunities for further design optimization of nanoengineered transparent electrodes. PMID:25073487

Giusti, Gal; Consonni, Vincent; Puyoo, Etienne; Bellet, Daniel

2014-08-27

157

Morphological and opto-electrical properties of a solution deposited platinum counter electrode for low cost dye sensitized solar cells.  

PubMed

Although platinum (Pt) is a rare and very expensive material, Pt counter electrodes are still very commonly used for reaching high efficiencies in dye-sensitized solar cells (DSCs). The use of alternative cheaper catalyst materials did not yet yield equivalent efficiencies. In this work, we tried to understand how to reduce the amount of deposited Pt-material and simultaneously deliver higher DSC performances. We systematically compared the properties of Pt-counter electrodes prepared by simple solution deposition methods such as spray-coating, dip-coating, brushing with reference to the Pt-electrodes prepared by sputtering onto fluorine doped-tin oxides (FTOs). The morphological and structural characterizations of the deposited Pt-layers were performed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The composition of Pt-material was quantified using SEM electron dispersive X-ray (EDX) mapping measurements which were further compared with optical transmission measurements. Also contact angle and sheet resistance measurements were performed. By taking Pt-layers composition, morphology and structural factors into account, 9.16% efficient N3 dye based DSCs were assembled. The DSCs were subjected to various opto-electrical characterization techniques like current-voltage (I-V), external quantum efficiency (EQE), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and transient photo voltage (TPV) measurements. The obtained experimental data suggest that the Pt counter electrodes prepared by solution deposition methods can also reach high DSC device performances with a consumption of very little amount of Pt material as compared with sputtered Pt-layers. This process also proves that higher DSC performances are not limited to the usage of sputtered Pt-layer as counter electrode. PMID:24146075

Thalluri, Gopala Krishna V V; Dcultot, Marc; Henrist, Catherine; Dewalque, Jennifer; Colson, Pierre; Habraken, Serge; Spoltore, Donato; Manca, Jean; Cloots, Rudi

2013-12-01

158

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

PubMed

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

Boccard, Mathieu; Battaglia, Corsin; Hnni, Simon; Sderstrm, Karin; Escarr, Jordi; Nicolay, Sylvain; Meillaud, Fanny; Despeisse, Matthieu; Ballif, Christophe

2012-03-14

159

Spectroscopic and Electrochemical Characterization of Nanostructured Optically-Transparent Carbon Electrodes  

PubMed Central

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

Benavidez, Tomas E.; Garcia, Carlos D.

2013-01-01

160

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

161

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

162

An organic surface modifier to produce a high work function transparent electrode for high performance polymer solar cells.  

PubMed

Modification of an ITO electrode with small-molecule organic surface modifier, 4-chloro-benzoic acid (CBA), via a simple spin-coating method produces a high-work-function electrode with high transparency and a hydrophobic surface. As an alternative to PEDOT:PSS, CBA modification achieves efficiency enhancement up to 8.5%, which is attributed to enhanced light absorption within the active layer and smooth hole transport from the active layer to the anode. PMID:25515353

Choi, Hyosung; Kim, Hak-Beom; Ko, Seo-Jin; Kim, Jin Young; Heeger, Alan J

2015-02-01

163

Performance improvement of dye-sensitized solar cells by surface patterning of fluorine-doped tin oxide transparent electrodes  

Microsoft Academic Search

The surface modification of fluorine-doped tin oxide (FTO) transparent electrodes was carried out by lithography and inductively coupled plasma etching to improve the conversion efficiency of dye-sensitized solar cells (DSSCs). The concentration of Cl2 gas and dc-bias voltage to the substrate were varied as the main etch parameters. The transmittance and sheet resistance of the FTO electrodes were compared before

Seon Mi Kong; Yubin Xiao; Kyung Ha Kim; Wan In Lee; Chee Won Chung

2011-01-01

164

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

165

Characterization of indium oxide for the use as a counter-electrode in an electrochromic device  

SciTech Connect

Thin films of indium oxide, In{sub 2}O{sub 3} (4000 {Angstrom}), deposited on commercially available In{sub 2}O{sub 3}: Sn (ITO)/glass by rf sputtering, have been examined for potential application as a counter-electrode material in an electrochromic device, based on their chemical, structural, and optical properties. Cyclic voltammetry experiments showed that mobile lithium ions can be inserted (chemical reduction) and removed (chemical oxidation) from the host structure of indium oxide. Coulometric titrations showed that the films exhibited a hysteresis behavior for the injection and removal of lithium ions in Li{sub x}In{sub 2}O{sub 3} (x=0-0.23). Structural investigations of the indium oxide films, utilizing electron diffraction techniques, indicated that they were crystalline with a crystallite size of 175 {Angstrom}, in agreement with x-ray diffraction results. Differences in optical transmission between the lithiated and delithiated thin films were no more than 5% in the visible/near-infrared regions of the spectrum. 6 refs., 5 figs., 1 tab.

Yu, P.C.; Haas, T.E. (Tufts Univ., Medford, MA (USA). Dept. of Chemistry); Goldner, R.B. (Tufts Univ., Medford, MA (USA). Electro-Optics Technology Center); Cogan, S.F. (EIC Labs., Inc., Norwood, MA (USA))

1991-01-01

166

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

PubMed

A composite counter electrode (CE) made of electrospun carbon nanofibers (ECNs) and platinum (Pt) nanoparticles has been demonstrated for the first time to improve the performance of dye-sensitized solar cells (DSCs). The new ECN-Pt composite CE exhibited a more efficient electro-catalytic performance with lower charge transfer resistance (R(ct)), larger surface area, and faster reaction rate than those of conventional Pt. It reduced the overall series resistance (R(se)), decreased dark saturation current density (J(0)) and increased shunt resistance (R(sh)) of the DSCs, thereby leading to a higher fill factor (FF) and larger open circuit voltage (V(oc)). The reduced electron transport resistance (R(s)) and faster charge transfer rate in the CE led to a smaller overall cell series resistance (R(se)) in the ECN-Pt composite based DSCs. The DSCs based on an ECN-Pt CE achieved a ? of ?8%, which was improved over those of pure Pt or ECN based cells. PMID:22743819

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

2012-08-01

167

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

168

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 (R(rms) < 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

169

Co-Electrophoretic Deposition Multiwall Carbon Nanotubes/Pt Counter Electrodes for Dye-Sensitized Solar Cell  

NASA Astrophysics Data System (ADS)

Multiwall carbon nanotubes (MWCNTs) and platinum (Pt) were coated on fluorine doped tin oxide (FTO) coated glass by a direct current electrophoretic method, and were used as dye-sensitized solar cell counter electrodes. Scanning electron microscopy (SEM) detected the deposition of carbon nanotubes on FTO-glass. The deposition of Pt nanoparticles on carbon nanotube surfaces was confirmed by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Cell efficiencies of MWCNTs, Pt and MWCNTs/Pt dye-sensitized solar cells (DSSCs) were 1.41, 8.13, and 8.90%, respectively. The improvement of the composited MWCNTs/Pt cell efficiency is due to the presence of both catalysts (MWCNTs and Pt) enhancing counter electrode catalytic activity as observed by cyclic voltammetry (CV) and reducing charge-transfer resistance as observed by electrochemical impedance spectroscopy (EIS).

Maiaugree, Wasan; Pimanpang, Samuk; Towannang, Madsakorn; Rutphonsan, Phikun; Laupa, Seksan; Jarernboon, Wirat; Amornkitbamrung, Vittaya

2012-10-01

170

The role of propagating modes in silver nanowire arrays for transparent electrodes.  

PubMed

Silver nanowires have been shown to demonstrate enhanced transmission and promising potential for next-generation transparent electrodes. In this paper, we systematically investigated the electrical and optical properties of 1D and 2D silver nanowire arrays as a function of diameter and pitch and compared their performance to that of silver thin films. Silver nanowires were found to exhibit enhanced transmission over thin films due to propagating resonance modes between nanowires. We evaluated the angular dependence and dispersion relation of these propagating modes and demonstrate that larger nanowire diameters and pitches are favored for achieving higher solar transmission at a particular sheet resistance. Silver nanowires may achieve achieve solar transmission > 90% with sheet resistances of a few ?/sq and figure of merit ?dc/?op > 1000. PMID:24104429

Gao, Tongchuan; Leu, Paul W

2013-05-01

171

Transparent Conducting Electrodes based on 1D and 2D Ag Nanogratings for Organic Photovoltaics  

E-print Network

The optical and electrical properties of optically-thin one-dimensional (1D) Ag nanogratings and two-dimensional (2D) Ag nanogrids are studied, and their use as transparent electrodes in organic photovoltaics are explored. A large broadband and polarization-insensitive optical absorption enhancement in the organic light-harvesting layers is theoretically and numerically demonstrated using either single-layer 2D Ag nanogrids or two perpendicular 1D Ag nanogratings, and is attributed to the excitation of surface plasmon resonances and plasmonic cavity modes. Total photon absorption enhancements of 150% and 200% are achieved for the optimized single-layer 2D Ag nanogrids and double (top and bottom) perpendicular 1D Ag nanogratings, respectively.

Zeng, Beibei; Bartoli, Filbert J

2014-01-01

172

Atomic Physics Effects on Convergent, Child-Langmuir Ion Flow between Nearly Transparent Electrodes  

SciTech Connect

Research during this project at the University of Wisconsin Fusion Technology Institute (UW FTI) on ion and neutral flow through an arbitrary, monotonic potential difference created by nearly transparent electrodes accomplished the following: (1) developed and implemented an integral equation approach for atomic physics effects in helium plasmas; (2) extended the analysis to coupled integral equations that treat atomic and molecular deuterium ions and neutrals; (3) implemented the key deuterium and helium atomic and molecular cross sections; (4) added negative ion production and related cross sections; and (5) benchmarked the code against experimental results. The analysis and codes treat the species D0, D20, D+, D2+, D3+, D and, separately at present, He0 and He+. Extensions enhanced the analysis and related computer codes to include He++ ions plus planar and cylindrical geometries.

Santarius, John F. [University of Wisconsin-Madison] [University of Wisconsin-Madison; Emmert, Gilbert A. [University of Wisconsin-Madison] [University of Wisconsin-Madison

2013-11-07

173

Electrostatic spray deposition of highly transparent silver nanowire electrode on flexible substrate.  

PubMed

In this work, a modified polyol synthesis by adding KBr and by replacing the AgCl with NaCl seed was used to obtain high quality silver nanowires with long aspect ratios with an average length of 13.5 ?m in length and 62.5 nm in diameter. The Ag nanowires suspended in methanol solution after removing any unwanted particles using a glass filter system were then deposited on a flexible polycarbonate substrate using an electrostatic spray system. Transmittance of 92.1% at wavelength of 550 nm with sheet resistance of 20 ?/sq and haze of 4.9% were measured for the electrostatic sprayed Ag nanowire transparent electrode. PMID:23277228

Kim, Taegeon; Canlier, Ali; Kim, Geun Hong; Choi, Jaeho; Park, Minkyu; Han, Seung Min

2013-02-01

174

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

175

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

176

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

177

A Method for Efficient Transmittance Spectrum Prediction of Transparent Composite Electrodes  

NASA Astrophysics Data System (ADS)

The interest in indium-free transparent composite electrode (TCE), a thin metal layer embedded between two transparent metal oxide (TMO) layers resulting in TMO/metal/TMO composite structure, has grown recently with the advent of their high figures of merit and its potential application in photovoltaic applications. However, most of the work to date has focused on experimentally producing the best optically transmitting TCE. To better design TCEs and minimize experimental work, it would be useful to develop a model that predicts the optical transmission. In the current work, the transfer-matrix method is employed to calculate the transmittance spectrum of TCE. To validate this approach, the transmittance spectra of TiO2/Au/TiO2 and TiO2/Ag/TiO2 multilayer thin-film TCEs are calculated with use of extracted material parameters. The calculated transmittance spectrum of TiO2/Au/TiO2 matches the measured spectrum quite well. However, the calcualted transmittance of TiO2/Ag/TiO2 is higher than its measured transmittance. The presence of voids in the Ag film is probably responsible for the decreased transmittance of the TiO2/Ag/TiO2 sample, and the continuous Au film in TiO2/Au/TiO2 ensures a good agreement between transmittance prediction and measurement. Our approach is a reliable tool to predict the optical transmittance of TCE with continuous films, and it can efficiently expedite the selection from numerous possible combinations of transparent metal oxides and metals when developing TCEs for future photovoltaic applications. It can also serve as a convenient method to assess the continuity of embedded metal layer.

Zhao, Zhao; Dhar, A.; Alford, T. L.

2015-02-01

178

Pt-free and efficient counter electrode with nanostructured CoNi2S4 for dye-sensitized solar cells.  

PubMed

The counter electrode has a great influence on the performance of the dye-sensitized solar cells (DSSCs). The research and development of Pt-free counter electrode is becoming one of the hot areas in the field of DSSCs. Herein, we successfully synthesized a ternary metal sulfide (CoNi2S4) nanostructure on FTO substrate by hydrothermal method and investigated its application as counter electrode. The as-synthesized sample could exhibit better electrocatalystic property than that of Pt, and corresponding DSSCs have comparable conversion efficiency with typical Pt catalyzed cells. The easy synthesis, low cost and excellent electrocatalytic property may help the CoNi2S4 nanostructure stand out as an alternative counter electrode in DSSCs. PMID:25799125

Shi, Zhiwei; Deng, Kaimo; Li, Liang

2015-01-01

179

Pt-free and efficient counter electrode with nanostructured CoNi2S4 for dye-sensitized solar cells  

PubMed Central

The counter electrode has a great influence on the performance of the dye-sensitized solar cells (DSSCs). The research and development of Pt-free counter electrode is becoming one of the hot areas in the field of DSSCs. Herein, we successfully synthesized a ternary metal sulfide (CoNi2S4) nanostructure on FTO substrate by hydrothermal method and investigated its application as counter electrode. The as-synthesized sample could exhibit better electrocatalystic property than that of Pt, and corresponding DSSCs have comparable conversion efficiency with typical Pt catalyzed cells. The easy synthesis, low cost and excellent electrocatalytic property may help the CoNi2S4 nanostructure stand out as an alternative counter electrode in DSSCs. PMID:25799125

Shi, Zhiwei; Deng, Kaimo; Li, Liang

2015-01-01

180

Potential-Assisted Adsorption of Bovine Serum Albumin onto Optically-Transparent Carbon Electrodes  

PubMed Central

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

Benavidez, Toms E.; Garcia, Carlos D.

2013-01-01

181

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

182

Water-bath assisted convective assembly of aligned silver nanowire films for transparent electrodes.  

PubMed

Manipulating Ag nanowire (AgNW) assembly to tailor the opto-electrical properties and surface morphology could improve the performance of next-generation transparent conductive electrodes. In this paper, we demonstrated a water-bath assisted convective assembly process at the temporary water/alcohol interface for fabricating hierarchical aligned AgNW electrodes. The convection flow plays an important role during the assembly process. The assembled AgNW film fabricated via three times orthogonal dip-coating at a water-bath temperature of 80 C has a sheet resistance of 11.4 ? sq(-1) with 89.9% transmittance at 550 nm. Moreover, the root mean square (RMS) of this assembled AgNW film was only 15.6 nm which is much lower than the spin-coated random AgNW film (37.6 nm) with a similar sheet resistance. This facile assembly route provides a new way for manufacturing and tailoring ordered nanowire-based devices. PMID:25726960

Duan, Sheng-Kai; Niu, Qiao-Li; Wei, Jun-Feng; He, Jie-Bing; Yin, Yi-An; Zhang, Yong

2015-03-11

183

Ag-Pd-Cu alloy inserted transparent indium tin oxide electrodes for organic solar cells  

SciTech Connect

The authors report on the characteristics of Ag-Pd-Cu (APC) alloy-inserted indium tin oxide (ITO) films sputtered on a glass substrate at room temperature for application as transparent anodes in organic solar cells (OSCs). The effect of the APC interlayer thickness on the electrical, optical, structural, and morphological properties of the ITO/APC/ITO multilayer were investigated and compared to those of ITO/Ag/ITO multilayer electrodes. At the optimized APC thickness of 8?nm, the ITO/APC/ITO multilayer exhibited a resistivity of 8.55??10{sup ?5} ? cm, an optical transmittance of 82.63%, and a figure-of-merit value of 13.54??10{sup ?3} ?{sup ?1}, comparable to those of the ITO/Ag/ITO multilayer. Unlike the ITO/Ag/ITO multilayer, agglomeration of the metal interlayer was effectively relieved with APC interlayer due to existence of Pd and Cu elements in the thin region of the APC interlayer. The OSCs fabricated on the ITO/APC/ITO multilayer showed higher power conversion efficiency than that of OSCs prepared on the ITO/Ag/ITO multilayer below 10?nm due to the flatness of the APC layer. The improved performance of the OSCs with ITO/APC/ITO multilayer electrodes indicates that the APC alloy interlayer prevents the agglomeration of the Ag-based metal interlayer and can decrease the thickness of the metal interlayer in the oxide-metal-oxide multilayer of high-performance OSCs.

Kim, Hyo-Joong; Seo, Ki-Won; Kim, Han-Ki, E-mail: imdlhkkim@khu.ac.kr [Department of Advanced Materials Engineering for Information and Electronics, Kyung-Hee University, 1 Seocheon-dong, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of); Noh, Yong-Jin; Na, Seok-In [Graduate School of Flexible and Printable Electronics, Chonbuk National University, 664-14, Deokjin-dong, Jeonju-si, Jeollabuk-do 561-756 (Korea, Republic of)

2014-09-01

184

Large-size, high-uniformity, random silver nanowire networks as transparent electrodes for crystalline silicon wafer solar cells.  

PubMed

Metal nanowire networks are emerging as next generation transparent electrodes for photovoltaic devices. We demonstrate the application of random silver nanowire networks as the top electrode on crystalline silicon wafer solar cells. The dependence of transmittance and sheet resistance on the surface coverage is measured. Superior optical and electrical properties are observed due to the large-size, highly-uniform nature of these networks. When applying the nanowire networks on the solar cells with an optimized two-step annealing process, we achieved as large as 19% enhancement on the energy conversion efficiency. The detailed analysis reveals that the enhancement is mainly caused by the improved electrical properties of the solar cells due to the silver nanowire networks. Our result reveals that this technology is a promising alternative transparent electrode technology for crystalline silicon wafer solar cells. PMID:24104422

Xie, Shouyi; Ouyang, Zi; Jia, Baohua; Gu, Min

2013-05-01

185

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

186

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

187

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

188

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

PubMed

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

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

2013-10-23

189

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

190

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

191

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

192

Electro-optic modulator with exceptional power-size performance enabled by transparent conducting electrodes.  

PubMed

An EO phase modulator having transparent conducting oxide electrodes and an inverted rib waveguide structure is demonstrated. This new modulator geometry employs an EO polymer having an in-device r33 = 60pm/V. The measured half-wave voltage Vpi of these devices ranges from 5.3V to 11.2V for 3.8 and 1.5 mm long devices, respectively. The lowest VpiL figure-of-merit corresponds to 0.6V-cm (7.2mW-cm(2) of power length product) in a dual-drive configuration. The trade-off between Vpi, insertion loss and modulation bandwidth is systematically analyzed. An optimized high-speed structure is proposed, with numerical simulation showing that this new structure and an in-device r33 = 150pm/V, can achieve Vpi = 0.5V in a 5mm long active length with dual drive operation. The insertion loss is targeted at 6dB, and a 3dB optical modulation bandwidth can reach > 40GHz. PMID:20389698

Yi, Fei; Ou, Fang; Liu, Boyang; Huang, Yingyan; Ho, Seng-Tiong; Wang, Yiliang; Liu, Jun; Marks, Tobin J; Huang, Su; Luo, Jingdong; Jen, Alex K-Y; Dinu, Raluca; Jin, Dan

2010-03-29

193

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

194

Copper nanowire-graphene core-shell nanostructure for highly stable transparent conducting electrodes.  

PubMed

A copper nanowire-graphene (CuNW-G) core-shell nanostructure was successfully synthesized using a low-temperature plasma-enhanced chemical vapor deposition process at temperatures as low as 400 C for the first time. The CuNW-G core-shell nanostructure was systematically characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman, and X-ray photoelectron spectroscopy measurements. A transparent conducting electrode (TCE) based on the CuNW-G core-shell nanostructure exhibited excellent optical and electrical properties compared to a conventional indium tin oxide TCE. Moreover, it showed remarkable thermal oxidation and chemical stability because of the tight encapsulation of the CuNW with gas-impermeable graphene shells. The potential suitability of CuNW-G TCE was demonstrated by fabricating bulk heterojunction polymer solar cells. We anticipate that the CuNW-G core-shell nanostructure can be used as an alternative to conventional TCE materials for emerging optoelectronic devices such as flexible solar cells, displays, and touch panels. PMID:25712446

Ahn, Yumi; Jeong, Youngjun; Lee, Donghwa; Lee, Youngu

2015-03-24

195

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

196

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

SciTech Connect

Transparent and reflecting electrodes are important parts of the structure of amorphous silicon solar cells. We report improved methods for depositing zinc oxide, deposition of tin nitride as a potential reflection-enhancing diffusion barrier between the a-Si and back metal electrodes. Highly conductive and transparent fluorine-doped zinc oxide was successfully produced on small areas by atmospheric pressure CVD from a less hazardous zinc precursor, zinc acetylacetonate. The optical properties measured for tin nitride showed that the back-reflection would be decreased if tin nitride were used instead of zinc oxide as a barrier layer over silver on aluminum. Niobium-doped titanium dioxide was produced with high enough electrical conductivity so that normal voltages and fill factors were obtained for a-Si cells made on it.

Gordon, R.G. [Harvard Univ., Cambridge, MA (United States)

1995-10-01

197

Enhanced efficiency of the dye-sensitized solar cells by excimer laser irradiated carbon nanotube network counter electrode  

SciTech Connect

The carbon nanotube network decorated with Pt nanoparticles (PtCNT) irradiated by excimer laser as counter electrode (CE) of dye-sensitized solar cells (DSSCs) has been systematically demonstrated. The conversion efficiency would be improved from 7.12% to 9.28% with respect to conventional Pt-film one. It was attributed to the enhanced catalytic surface from Pt nanoparticles and the improved conductivity due to the adjoining phenomenon of PtCNTs irradiated by laser. Moreover, the laser annealing could also promote the interface contact between CE and conductive glass. Therefore, such a simple laser-irradiated PtCNT network is promising for the future flexible DSSCs applications.

Chien, Yun-San, E-mail: u930347@oz.nthu.edu.tw; Fu, Wei-En [Center for Measurement Standards, Industrial Technology Research Institute, Hsinchu, Taiwan (China); Yang, Po-Yu [Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan (China); Lee, I-Che; Chu, Chih-Chieh; Chou, Chia-Hsin; Cheng, Huang-Chung [Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu, Taiwan (China)

2014-02-03

198

Highly efficient telluride electrocatalysts for use as Pt-free counter electrodes in dye-sensitized solar cells.  

PubMed

Two transition metal tellurides, CoTe and NiTe2, were synthesized and for the first time employed as the counter electrodes (CEs) with high catalytic activity for reduction of I3(-) in dye-sensitized solar cells (DSCs). Using CoTe and NiTe2-based CEs, photoelectric conversion efficiencies (PCEs) of 6.92% and 7.21% were achieved for DSCs, respectively, comparable to that of 7.04% achieved when using a Pt-based CE. The results indicated that, serving as a CE in DSCs, telluride could be a cost-effective and efficient alternative to the noble metal Pt. PMID:24048371

Guo, Jiahao; Shi, Yantao; Chu, Yuting; Ma, Tingli

2013-10-01

199

Voltage-controlled liquid-crystal terahertz phase shifter with indium-tin-oxide nanowhiskers as transparent electrodes.  

PubMed

Indium-tin-oxide nanowhiskers were employed as transparent electrodes in a liquid-crystal terahertz phase shifter. Transmittance of the device was as high as ?75%. Phase shift exceeding ?/2 at 1.0THz is achieved in a ?500???m-thick cell. The driving voltage required for the device operating as a quarter-wave plate was as low as 17.68V (rms), an improvement of nearly an order of magnitude over previous work. PMID:24979031

Yang, Chan-Shan; Tang, Tsung-Ta; Chen, Po-Han; Pan, Ru-Pin; Yu, Peichen; Pan, Ci-Ling

2014-04-15

200

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

201

Highly transparent front electrodes with metal fingers for p-i-n thin-film silicon solar cells  

NASA Astrophysics Data System (ADS)

The optical and electrical properties of transparent conductive oxides (TCOs), traditionally used in thin-film silicon (TF-Si) solar cells as front-electrode materials, are interlinked, such that an increase in TCO transparency is generally achieved at the cost of reduced lateral conductance. Combining a highly transparent TCO front electrode of moderate conductance with metal fingers to support charge collection is a well-established technique in wafer-based technologies or for TF-Si solar cells in the substrate (n-i-p) configuration. Here, we extend this concept to TF-Si solar cells in the superstrate (p-i-n) configuration. The metal fingers are used in conjunction with a millimeter-scale textured foil, attached to the glass superstrate, which provides an antireflective and retroreflective effect; the latter effect mitigates the shadowing losses induced by the metal fingers. As a result, a substantial increase in power conversion efficiency, from 8.7% to 9.1%, is achieved for 1-?m-thick microcrystalline silicon solar cells deposited on a highly transparent thermally treated aluminum-doped zinc oxide layer combined with silver fingers, compared to cells deposited on a state-of-the-art zinc oxide layer.

Moulin, Etienne; Mller, Thomas Christian Mathias; Warzechac, Marek; Hoffmann, Andre; Paetzold, Ulrich Wilhelm; Aeberhard, Urs

2015-03-01

202

Optically transparent thin-film transistors based on 2D multilayer MoS2 and indium zinc oxide electrodes  

NASA Astrophysics Data System (ADS)

We report on optically transparent thin film transistors (TFTs) fabricated using multilayered molybdenum disulfide (MoS2) as the active channel, indium tin oxide (ITO) for the back-gated electrode and indium zinc oxide (IZO) for the source/drain electrodes, respectively, which showed more than 81% transmittance in the visible wavelength. In spite of a relatively large Schottky barrier between MoS2 and IZO, the n-type behavior with a field-effect mobility (?eff) of 1.4 cm2 V?1 s?1 was observed in as-fabricated transparent MoS2 TFT. In order to enhance the performances of transparent MoS2 TFTs, a picosecond pulsed laser was selectively irradiated onto the contact region of the IZO electrodes. Following laser annealing, ?eff increased to 4.5 cm2 V?1 s?1, and the on-off current ratio (Ion/Ioff) increased to 104, which were attributed to the reduction of the contact resistance between MoS2 and IZO.

Kwon, Junyeon; Hong, Young Ki; Kwon, Hyuk-Jun; Park, Yu Jin; Yoo, Byungwook; Kim, Jiwan; Grigoropoulos, Costas P.; Oh, Min Suk; Kim, Sunkook

2015-01-01

203

Optically transparent thin-film transistors based on 2D multilayer MoS? and indium zinc oxide electrodes.  

PubMed

We report on optically transparent thin film transistors (TFTs) fabricated using multilayered molybdenum disulfide (MoS2) as the active channel, indium tin oxide (ITO) for the back-gated electrode and indium zinc oxide (IZO) for the source/drain electrodes, respectively, which showed more than 81% transmittance in the visible wavelength. In spite of a relatively large Schottky barrier between MoS2 and IZO, the n-type behavior with a field-effect mobility (?(eff)) of 1.4 cm(2) V(-1) s(-1) was observed in as-fabricated transparent MoS2 TFT. In order to enhance the performances of transparent MoS2 TFTs, a picosecond pulsed laser was selectively irradiated onto the contact region of the IZO electrodes. Following laser annealing, ?(eff) increased to 4.5 cm(2) V(-1) s(-1), and the on-off current ratio (I(on)/I(off)) increased to 10(4), which were attributed to the reduction of the contact resistance between MoS2 and IZO. PMID:25548952

Kwon, Junyeon; Hong, Young Ki; Kwon, Hyuk-Jun; Park, Yu Jin; Yoo, Byungwook; Kim, Jiwan; Grigoropoulos, Costas P; Oh, Min Suk; Kim, Sunkook

2015-01-21

204

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

PubMed Central

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

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

2014-01-01

205

Highly electrocatalytic Cu?ZnSn(S?-xSex)? counter electrodes for quantum-dot-sensitized solar cells.  

PubMed

Traditional Pt counter electrode in quantum-dot-sensitized solar cells suffers from a low electrocatalytic activity and instability due to irreversible surface adsorption of sulfur species incurred while regenerating polysulfide (S(n)(2-)/S(2-)) electrolytes. To overcome such constraints, chemically synthesized Cu(2)ZnSn(S(1-x)Se(x))(4) nanocrystals were evaluated as an alternative to Pt. The resulting chalcogenides exhibited remarkable electrocatalytic activities for reduction of polysulfide (S(n)(2-)) to sulfide (S(2-)), which were dictated by the ratios of S/Se. In this study, a quantum dot sensitized solar cell constructed with Cu(2)ZnSn(S(0.5)Se(0.5))(4) as a counter electrode showed the highest energy conversion efficiency of 3.01%, which was even higher than that using Pt (1.24%). The compositional variations in between Cu(2)ZnSnS(4) (x = 0) and Cu(2)ZnSnSe(4) (x = 1) revealed that the solar cell performances were closely related to a difference in electrocatalytic activities for polysulfide reduction governed by the S/Se ratios. PMID:23298364

Cao, Yuebin; Xiao, Yanjun; Jung, Jin-Young; Um, Han-Don; Jee, Sang-Won; Choi, Hye Mi; Bang, Jin Ho; Lee, Jung-Ho

2013-02-01

206

p-Type mesoscopic NiO as an active interfacial layer for carbon counter electrode based perovskite solar cells.  

PubMed

Replacement of the ZrO2 insulator layer in the state-of-the-art TiO2/ZrO2/carbon structure by mesoscopic p-type NiO particles led to 39% increase of energy conversion efficiency of hole-conductor-free organometallic perovskite heterojunction solar cells with carbon counter electrodes. In these cells, the light absorber, CH3NH3PbI3, formed instantly inside the pores of the entire TiO2/NiO/carbon layer upon sequential deposition of PbI2 and CH3NH3I. Photoluminescence, impedance spectroscopy and transient photovoltage decay measurements have revealed that introduction of NiO extended the electron lifetime and augmented the hole extraction of the counter electrode. As a result, the photocurrent and open-circuit voltage both increased, resulting in a cell with impressive energy conversion efficiency of 11.4% under AM1.5G conditions. PMID:25406840

Liu, Zonghao; Zhang, Meng; Xu, Xiaobao; Bu, Lingling; Zhang, Wenjun; Li, Wenhui; Zhao, Zhixin; Wang, Mingkui; Cheng, Yi-Bing; He, Hongshan

2015-02-17

207

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

208

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

209

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

210

Ultra-thin and smooth transparent electrode for flexible and leakage-free organic light-emitting diodes.  

PubMed

A smooth, ultra-flexible, and transparent electrode was developed from silver nanowires (AgNWs) embedded in a colorless polyimide (cPI) by utilizing an inverted film-processing method. The resulting AgNW-cPI composite electrode had a transparency of >80%, a low sheet resistance of 8 ?/?, and ultra-smooth surfaces comparable to glass. Leveraging the robust mechanical properties and flexibility of cPI, the thickness of the composite film was reduced to less than 10??m, which is conducive to extreme flexibility. This film exhibited mechanical durability, for both outward and inward bending tests, up to a bending radius of 30??m, while maintaining its electrical performance under cyclic bending (bending radius: 500??m) for 100,000 iterations. Phosphorescent, blue organic light-emitting diodes (OLEDs) were fabricated using these composites as bottom electrodes (anodes). Hole-injection was poor, because AgNWs were largely buried beneath the composite's surface. Thus, we used a simple plasma treatment to remove the thin cPI layer overlaying the nanowires without introducing other conductive materials. As a result, we were able to finely control the flexible OLEDs' electroluminescent properties using the enlarged conductive pathways. The fabricated flexible devices showed only slight performance reductions of <3% even after repeated foldings with a 30??m bending radius. PMID:25824143

Ok, Ki-Hun; Kim, Jiwan; Park, So-Ra; Kim, Youngmin; Lee, Chan-Jae; Hong, Sung-Jei; Kwak, Min-Gi; Kim, Namsu; Han, Chul Jong; Kim, Jong-Woong

2015-01-01

211

Ultra-thin and smooth transparent electrode for flexible and leakage-free organic light-emitting diodes  

PubMed Central

A smooth, ultra-flexible, and transparent electrode was developed from silver nanowires (AgNWs) embedded in a colorless polyimide (cPI) by utilizing an inverted film-processing method. The resulting AgNW-cPI composite electrode had a transparency of >80%, a low sheet resistance of 8 ?/?, and ultra-smooth surfaces comparable to glass. Leveraging the robust mechanical properties and flexibility of cPI, the thickness of the composite film was reduced to less than 10??m, which is conducive to extreme flexibility. This film exhibited mechanical durability, for both outward and inward bending tests, up to a bending radius of 30??m, while maintaining its electrical performance under cyclic bending (bending radius: 500??m) for 100,000 iterations. Phosphorescent, blue organic light-emitting diodes (OLEDs) were fabricated using these composites as bottom electrodes (anodes). Hole-injection was poor, because AgNWs were largely buried beneath the composite's surface. Thus, we used a simple plasma treatment to remove the thin cPI layer overlaying the nanowires without introducing other conductive materials. As a result, we were able to finely control the flexible OLEDs' electroluminescent properties using the enlarged conductive pathways. The fabricated flexible devices showed only slight performance reductions of <3% even after repeated foldings with a 30??m bending radius. PMID:25824143

Ok, Ki-Hun; Kim, Jiwan; Park, So-Ra; Kim, Youngmin; Lee, Chan-Jae; Hong, Sung-Jei; Kwak, Min-Gi; Kim, Namsu; Han, Chul Jong; Kim, Jong-Woong

2015-01-01

212

Highly catalytic counter electrodes for organic redox couple of thiolate/disulfide in dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

We synthesized a low-cost, highly catalytic tungsten carbide that was embedded in ordered mesoporous carbon (WC-OMC). This was used as a counter electrode (CE) in dye-sensitized solar cells (DSCs). For comparison, we also evaluated the catalytic activity of bare WC, and several normal carbon materials for the organic redox couple of thiolate/disulfide (T-/T2). The DSCs showed highly photovoltaic conversion efficiencies, ranging from 4.75% to 5.34%. The efficiency of the DSC composed of WC-OMC was 45% higher than that of Pt. Based on kinetic studies, the increased efficiency was caused by the increased exchange current density and decreased charge transfer resistance.

Wang, Liang; Wu, Mingxing; Gao, Yurong; Ma, Tingli

2011-05-01

213

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

214

Preparation of polypyrrole thin film counter electrode with pre-stored iodine and resultant influence on its performance  

NASA Astrophysics Data System (ADS)

The performance of DSSCs can be improved if iodine species can be pre-stored in the polymer counter electrodes (CEs) since the I-/I3- redox couple is usually used as the mediator in electrolyte for DSSCs. In this work, such porous polypyrrole (PPy) CEs have been successfully synthesized by electrochemical method. Detailed mechanism about the electro-polymerization and film growth has been investigated both experimentally and theoretically. The influence of iodine species pre-stored in the film during polymerization on the properties of resultant PPy CEs (such as porous structure, doping state, and electrocatalytic activity) and, thereby, the device performance has been studied thoroughly. We envision that the results may help to facilitate the research and development of the polymer-based CEs used in DSSCs.

Lu, Shan; Zhang, Xuehua; Feng, Ting; Han, Ruobing; Liu, Dongsheng; He, Tao

2015-01-01

215

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

216

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

SciTech Connect

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

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

2013-11-25

217

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

NASA Astrophysics Data System (ADS)

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

Kitamura, Koji; Shiratori, Seimei

2011-05-01

218

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

PubMed

A thin film of poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonic acid) (PEDOT-PSS), which is an alternative cathodic catalyst for Pt in dye-sensitized solar cells, was prepared using the layer-by-layer self-assembly method (LbL). The film is highly adhesive to the substrate and has a controllable thickness. Therefore, the PEDOT-PSS film prepared using LbL is expected have high performance and durability as a counter electrode. Moreover, when carbon black was added to the PEDOT-PSS solution, highly mesoporous PEDOT-PSS and carbon black hybrid films were obtained. These films showed high cathodic activity. In this study, we investigated the change in morphology in the obtained film with increasing carbon black content, and the influence of the porosity and thickness on the performance of the cells. In this study, a Pt-free counter electrode with performance similar to that of Pt-based counter electrodes was successfully fabricated. The achieved efficiency of 4.71% was only a factor of 8% lower than that of the cell using conventional thermally deposited Pt on fluorine-doped tin oxide glass counter electrodes. PMID:21430326

Kitamura, Koji; Shiratori, Seimei

2011-05-13

219

The facile preparation of a cobalt disulfide-reduced graphene oxide composite film as an efficient counter electrode for dye-sensitized solar cells.  

PubMed

Cobalt disulfide (CoS2)-reduced graphene oxide (RGO) composite (CSG) films, which are prepared by combining the layer by layer assembly method and thermal treatment process, are used as counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The DSSC with CSG CE exhibits comparable efficiency to the cell with the Pt CE. PMID:25525643

Sun, Lijuan; Bai, Yu; Zhang, Naiqing; Sun, Kening

2015-02-01

220

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

221

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

222

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

223

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

SciTech Connect

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

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

1998-05-01

224

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

225

Application of High Surface Area Tin-Doped Indium Oxide Nanoparticle Films as Transparent Conducting Electrodes  

SciTech Connect

Metal complex derivatized, optically transparent nanoparticle films of Sn(IV)-doped In2O3 (nanoITO) undergo facile interfacial electron transfer allowing for rapid, potential controlled color changes, direct spectral (rather than current) monitoring of voltammograms, and multilayer catalysis of water oxidation.

Hoertz, Paul G.; Chen, Zuofeng; Kent, Caleb A.; Meyer, Thomas J.

2010-01-01

226

Tungsten trioxide nanoplate array supported platinum as a highly efficient counter electrode for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

A tungsten trioxide (WO3) nanoplate array is fabricated directly on the FTO/glass substrate and used as a platinum (Pt) nanoscale supporter for a highly efficient and low Pt-consumption counter electrode (CE) in dye-sensitized solar cells (DSCs). A Pt/WO3 composite structure, with Pt nanoparticles having a diameter of 2-3 nm, increases the electrochemical catalytic activity in catalyzing the reduction of triiodide. Accordingly, the power conversion efficiency is increased from less than 1% for WO3 CE and 8.1% for Pt CE, respectively, to 8.9% for Pt/WO3 CE. Moreover, the use of Pt/WO3 CE can dramatically reduce the consumption of scarce Pt material, with a relatively low Pt-loading of ~2 ?g cm-2, while maintaining a much better performance. The excellent performance of Pt/WO3 CE is attributed to the efficient electron injection and transport via WO3 supporters, as well as the nanostructure array morphology of WO3 for deposition of fine Pt nanoparticles. This work provides an approach for developing highly catalytic and low-cost Pt based CEs, which also has implications for the development of Pt/WO3 nanoplate arrays for other applications.A tungsten trioxide (WO3) nanoplate array is fabricated directly on the FTO/glass substrate and used as a platinum (Pt) nanoscale supporter for a highly efficient and low Pt-consumption counter electrode (CE) in dye-sensitized solar cells (DSCs). A Pt/WO3 composite structure, with Pt nanoparticles having a diameter of 2-3 nm, increases the electrochemical catalytic activity in catalyzing the reduction of triiodide. Accordingly, the power conversion efficiency is increased from less than 1% for WO3 CE and 8.1% for Pt CE, respectively, to 8.9% for Pt/WO3 CE. Moreover, the use of Pt/WO3 CE can dramatically reduce the consumption of scarce Pt material, with a relatively low Pt-loading of ~2 ?g cm-2, while maintaining a much better performance. The excellent performance of Pt/WO3 CE is attributed to the efficient electron injection and transport via WO3 supporters, as well as the nanostructure array morphology of WO3 for deposition of fine Pt nanoparticles. This work provides an approach for developing highly catalytic and low-cost Pt based CEs, which also has implications for the development of Pt/WO3 nanoplate arrays for other applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr06787h

Song, Dandan; Cui, Peng; Zhao, Xing; Li, Meicheng; Chu, Lihua; Wang, Tianyue; Jiang, Bing

2015-03-01

227

A dye-sensitized solar cell based on natural photosensitizers and a PEDOT:PSS/TiO2 film as a counter electrode  

NASA Astrophysics Data System (ADS)

Poly(3, 4-ethylendioxythiophene)-poly(styrene sulfonate) mixed with TiO2 nanoparticles (PEDOT:PSS/TiO2) was used as a catalyst for tri-iodide reduction in dye-sensitized solar cells based on natural photosensitizers. A PEDOT:PSS/TiO2 film was coated on a conductive glass substrate by the spin coating method. The solar cells were fabricated, having the PEDOT:PSS/TiO2 film as a counter electrode and Pomegranate juice dye-sensitized TiO2 as an anode. The morphology of PEDOT:PSS/TiO2 films was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM) images. Cyclic voltammetry (CV) was employed to characterize the catalytic activity of the PEDOT:PSS/TiO2 film. Based on the analysis of CV, the enhancements for the electrochemical and photochemical performance of the PEDOT:PSS/TiO2 electrode are attributed to the fact that the dispersed TiO2 nanoparticles in the PEDOT:PSS matrix provide an improved catalytic activity and a facilitated diffusion for tri-iodide ions. The energy conversion efficiency is significantly improved after TiO2 nanoparticle incorporation. This improvement might be attributed to an increase in the counter electrode catalytic activity. The highest efficiency of 0.73% was obtained by using 100 nm TiO2 nanoparticles in the counter electrode.

Jafari, Fatemeh; Behjat, Abbas; Khoshroo, Ali R.; Ghoshani, Maral

2015-02-01

228

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

Microsoft Academic Search

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

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

1995-01-01

229

High-conductivity large-area semi-transparent electrodes for polymer photovoltaics by silk screen printing and vapour-phase deposition  

Microsoft Academic Search

Transparent electrodes based on PEDOT were prepared using a variety of techniques suitable for large area applications from 3,4-ethylenedioxythiophene (EDT) and Fe(III)-tosylate. High conductivities were obtained (?20??1) with moderate transmission in the UV-visible range 350600nm. We subsequently demonstrate the application of PEDOT electrodes to flexible polyethyleneterphthalate plastic substrates (PET) prepared by this procedure for polymer photovoltaic devices with active areas

Bjrn Winther-Jensen; Frederik C. Krebs

2006-01-01

230

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

Microsoft Academic Search

Poor interfacial contact is often encountered in nanoparticulate film-based devices. The dye-sensitized solar cell (DSSC) is a representative case in which a nanoporous TiO2 electrode needs to be prepared on the transparent conducting oxide (TCO)-coated glass substrate. In this study, we demonstrate that the inter-electrode contact resistance accounts for a considerable portion of the total resistance of a DSSC and

Jinsoo Kim; Jonghyun Kim; Myeongkyu Lee

2010-01-01

231

Transparent low-work-function indium tin oxide electrode obtained by molecular scale interface engineering  

NASA Astrophysics Data System (ADS)

A redox reaction between a monolayer of electron-donor molecules, tetrakis(dimethylamino)ethylene, and the indium tin oxide (ITO) surface results in a decrease of the ITO work function down to 3.7eV. The modified ITO surface may be used as electron injecting electrode in polymer light-emitting devices. Photoelectron spectroscopy measurements show that the low-work-function of the modified electrode remains upon exposure to air or gentle annealing; thus, making it a good candidate for inexpensive fabrication of organic/polymeric (opto)electronic devices.

Osikowicz, W.; Crispin, X.; Tengstedt, C.; Lindell, L.; Kugler, T.; Salaneck, W. R.

2004-08-01

232

Enhancement of the efficiency of dye-sensitized solar cell with multi-wall carbon nanotubes/polypyrrole composite counter electrodes prepared by electrophoresis/electrochemical polymerization  

SciTech Connect

Graphical abstract: The overall energy conversion efficiency of the DSSC employing the MWCNT/PPy CE reached 3.78%. Compared with a reference DSSC using single MWCNT film CE with efficiency of 2.68%, the energy conversion efficiency was increased by 41.04%. Highlights: ? MWCNT/PPy composite film prepared by electrodeposition layer by layer was used as counter electrode in DSSC. ? The overall energy conversion efficiency of the DSSC was 3.78% by employing the composite film. ? The energy conversion efficiency increased by 41.04% compared with efficiency of 2.68% by using the single MWCNT film. ? We analyzed the mechanism and influence factor of electron transfer in the composite electrode by EIS. - Abstract: For the purpose of replacing the precious Pt counter electrode in dye-sensitized solar cells (DSSCs) with higher energy conversion efficiency, multi-wall carbon nanotube (MWCNT)/polypyrrole (PPy) double layers film counter electrode (CE) was fabricated by electrophoresis and cyclic voltammetry (CV) layer by layer. Atom force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscope (TEM) demonstrated the morphologies of the composite electrode and Raman spectroscopy verified the PPy had come into being. The overall energy conversion efficiency of the DSSC employing the MWCNT/PPy CE reached 3.78%. Compared with a reference DSSC using single MWCNT film CE with efficiency of 2.68%, the energy conversion efficiency was increased by 41.04%. The result of impedance showed that the charge transfer resistance R{sub ct} of the MWCNT/PPy CE had the lowest value compared to that of MWCNT or PPy electrode. These results indicate that the composite film with high conductivity, high active surface area, and good catalytic properties for I{sub 3}{sup ?} reduction can potentially be used as the CE in a high-performance DSSC.

Luo, Jun; Niu, Hai-jun; Wen, Hai-lin [Key Laboratory of Functional Inorganic Material Chemistry (Heilongjiang University), Ministry of Education, Department of Macromolecular Material and Engineering, Heilongjiang University, Harbin 150086 (China); Wu, Wen-jun; Zhao, Ping [Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237 (China); Wang, Cheng; Bai, Xu-duo [Key Laboratory of Functional Inorganic Material Chemistry (Heilongjiang University), Ministry of Education, Department of Macromolecular Material and Engineering, Heilongjiang University, Harbin 150086 (China); Wang, Wen, E-mail: haijunniu@hotmail.com [School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150080 (China)

2013-03-15

233

Tungsten trioxide nanoplate array supported platinum as a highly efficient counter electrode for dye-sensitized solar cells.  

PubMed

A tungsten trioxide (WO3) nanoplate array is fabricated directly on the FTO/glass substrate and used as a platinum (Pt) nanoscale supporter for a highly efficient and low Pt-consumption counter electrode (CE) in dye-sensitized solar cells (DSCs). A Pt/WO3 composite structure, with Pt nanoparticles having a diameter of 2-3 nm, increases the electrochemical catalytic activity in catalyzing the reduction of triiodide. Accordingly, the power conversion efficiency is increased from less than 1% for WO3 CE and 8.1% for Pt CE, respectively, to 8.9% for Pt/WO3 CE. Moreover, the use of Pt/WO3 CE can dramatically reduce the consumption of scarce Pt material, with a relatively low Pt-loading of ?2 ?g cm(-2), while maintaining a much better performance. The excellent performance of Pt/WO3 CE is attributed to the efficient electron injection and transport via WO3 supporters, as well as the nanostructure array morphology of WO3 for deposition of fine Pt nanoparticles. This work provides an approach for developing highly catalytic and low-cost Pt based CEs, which also has implications for the development of Pt/WO3 nanoplate arrays for other applications. PMID:25743611

Song, Dandan; Cui, Peng; Zhao, Xing; Li, Meicheng; Chu, Lihua; Wang, Tianyue; Jiang, Bing

2015-03-19

234

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

235

Highly effective nickel sulfide counter electrode catalyst prepared by optimal hydrothermal treatment for quantum dot-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Nickel sulfide (NiS) thin film has been deposited on a fluorine-doped tin oxide substrate by a hydrothermal method using 3-mercaptopropionic acid and used as an efficient counter electrode (CE) for polysulfide redox reactions in quantum dot-sensitized solar cells (QDSSCs). NiS has low toxicity and environmental compatibility. In the present study, the size of the NiS nanoparticle increases with the hydrothermal deposition time. The performance of the QDSSCs is examined in detail using polysulfide electrolyte with the NiS CE. A TiO2/CdS/CdSe/ZnS-based QDSSC using the NiS CE shows enhanced photovoltaic performance with a power conversion efficiency (PCE) of 3.03%, which is superior to that of a cell with Pt CE (PCE 2.20%) under one sun illumination (AM 1.5, 100mWcm-2). The improved photovoltaic performance of the NiS-based QDSSC may be attributed to a low charge transfer resistance (5.08?) for the reduction of polysulfide on the CE, indicating greater electrocatalytic activity of the NiS. Electrochemical impedance spectroscopy, cyclic voltammetry, and Tafel-polarization measurements were used to investigate the electrocatalytic activity of the NiS and Pt CEs.

Gopi, Chandu V. V. M.; Srinivasa Rao, S.; Kim, Soo-Kyoung; Punnoose, Dinah; Kim, Hee-Je

2015-02-01

236

NH3-treated WO3 as low-cost and efficient counter electrode for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

A novel low-cost and efficient counter electrode (CE) was obtained by treating catalytic inert tungsten trioxide (WO3) nanomaterial in NH3 atmosphere at elevated temperatures. The formation of tungsten oxynitride from WO3 after NH3 treatment, as evidenced by X-ray photoelectron spectroscopy and X-ray diffraction, increases the catalytic activity of the CE. Correspondingly, the power conversion efficiency (PCE) of the DSC is significantly increased from 0.9% for pristine WO3 CE to 5.9% for NH3-treated WO3 CE. The photovoltaic performance of DSC using NH3-treated WO3 CE is comparable to that of DSC using standard Pt CE (with a PCE of 6.0%). In addition, it is also shown that NH3 treatment is more efficient than H2 or N2 treatment in enhancing the catalytic performance of WO3 CE. This work highlights the potential of NH3-treated WO3 for the application in DSCs and provides a facile method to get highly efficient and low-cost CEs from catalytic inert metal oxides.

Song, Dandan; Chen, Zhao; Cui, Peng; Li, Meicheng; Zhao, Xing; Li, Yaoyao; Chu, Lihua

2015-01-01

237

Dually functional, N-doped porous graphene foams as counter electrodes for dye-sensitized solar cells.  

PubMed

A series of nitrogen-doped porous graphene foams (NPGFs) have been prepared by hydrothermally treating a mixed solution of graphite oxide (GO) and ammonia. The NPGFs are used as the counter electrode (CE) material for dye-sensitized solar cells (DSCs) in conjunction with the conventional iodide-based electrolyte and the recently developed sulfide-based electrolyte. Tafel-polarization tests and electrochemical impedance spectroscopic (EIS) measurements confirmed that the NPGFs work efficiently in both electrolyte systems, and under air mass (AM) 1.5G 100 mW cm(-2) light illumination, optimal efficiencies of 4.5% and 2.1% were obtained for the iodide-based electrolyte and sulfide-based electrolyte, respectively. To the best of our knowledge, this is the first study on N-doped graphene CEs in conjunction with sulfide-based electrolytes and therefore, the current results are deemed to provide new insights into developing novel low-cost and metal-free CEs for DSCs. PMID:25199841

Song, Long; Luo, Qiang; Zhao, Fei; Li, Yang; Lin, Hong; Qu, Liangti; Zhang, Zhipan

2014-10-21

238

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

239

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

240

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

Microsoft Academic Search

A thin film of poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonic acid) (PEDOT-PSS), which is an alternative cathodic catalyst for Pt in dye-sensitized solar cells, was prepared using the layer-by-layer self-assembly method (LbL). The film is highly adhesive to the substrate and has a controllable thickness. Therefore, the PEDOT-PSS film prepared using LbL is expected have high performance and durability as a counter electrode. Moreover, when

Koji Kitamura; Seimei Shiratori

2011-01-01

241

Electropolymerization of a poly(3,4-ethylenedioxythiophene) and functionalized, multi-walled, carbon nanotubes counter electrode for dye-sensitized solar cells and characterization of its performance  

Microsoft Academic Search

Composite films of poly(3,4-ethylenedioxythiophene) and functionalized, multi-walled, carbon nanotubes (PEDOTMWCNT) were fabricated by a simple oxidative electropolymerization method. These films were formed on fluorine-doped, tin oxide, glass substrates as counter electrodes (CEs) of platinum-free, dye-sensitized solar cells (DSSCs). The surface morphology, formation mechanism and electrochemical nature of PEDOTMWCNT films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM),

Jun Zhang; Xiaoxue Li; Wei Guo; Tubshin Hreid; Jinfeng Hou; Haiquan Su; Zhuobin Yuan

2011-01-01

242

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

2014-11-28

243

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

244

Aluminum-doped zinc oxide films as transparent conductive electrode for organic light-emitting devices  

Microsoft Academic Search

Highly transparent conductive, aluminum-doped zinc oxide (ZnO:Al) films were deposited on glass substrates by midfrequency magnetron sputtering of metallic aluminum-doped zinc target. ZnO:Al films with surface work functions between 3.7 and 4.4 eV were obtained by varying the sputtering conditions. Organic light-emitting diodes (OLEDs) were fabricated on these ZnO:Al films. A current efficiency of higher than 3.7 cd\\/A, was achieved.

X. Jiang; F. L. Wong; M. K. Fung; S. T. Lee

2003-01-01

245

Transparent conductive electrodes from graphene/PEDOT:PSS hybrid inks for ultrathin organic photodetectors.  

PubMed

A novel solution fabrication of large-area, highly conductive graphene films by spray-coating of a hybrid ink of exfoliated graphene (EG)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (PH1000) is demonstrated. The fabricated graphene films exhibit excellent mechanical properties, thus enabling their application as bottom electrodes in ultrathin organic photodetector devices with performance comparable to that of the state-of-the-art Si-based inorganic photodetectors. PMID:25448315

Liu, Zhaoyang; Parvez, Khaled; Li, Rongjin; Dong, Renhao; Feng, Xinliang; Mllen, Klaus

2015-01-27

246

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

247

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

248

Flexible and transparent organic film speaker by using highly conducting PEDOT\\/PSS as electrode  

Microsoft Academic Search

Flexible organic film speaker (FOFS) was fabricated with ion-assisted-reaction (IAR) treated poly(vinylidene fluoide) (PVDF) as active layer and poly(3,4-ethylenedioxythiophene)\\/poly(4-styrenesulfonate) (PEDOT\\/PSS), indium tin oxide (ITO), or copper (Cu) as electrode. The PEDOT\\/PSS materials were screen printed on the PVDF surface. The dc conductivity (?dc) of pristine PEDOT\\/PSS increases from 0.8 to ?80S\\/cm by adding various organic solvents. The sound pressure level

C. S. Lee; J. Y. Kim; D. E. Lee; J. Joo; B. G. Wagh; S. Han; Y. W. Beag; S. K. Koh

2003-01-01

249

Tuning the electrical and optical properties of graphene by ozone treatment for patterning monolithic transparent electrodes.  

PubMed

Tunable electrical and optical properties of graphene are vital to promote its use as film electrodes in a variety of devices. We developed an etching-free ozone treatment method to continuously tune the electrical resistance and optical transmittance of graphene films by simply varying the time and temperature of graphene exposure to ozone. Initially, ozone exposure dramatically decreases the electrical resistance of graphene films by p-doping, but this is followed by increases in the resistance and optical transmittance as a result of surface oxidation. The rate of resistance increase can be significantly increased by raising the treatment temperature. The ozone-oxidized graphene is not removed but is gradually transformed to graphene oxide (GO). On the basis of such effects of ozone treatment, we demonstrate a well-defined graphene pattern by using ozone photolithography, in which the ozone-treated graphene electrodes are monolithic but separated by insulating GO regions. Such a monolithic graphene pattern shows low optical contrast, a clean and more hydrophilic surface, indicating the promising use of ozone treatment to achieve high-performance graphene-based optoelectronic devices. PMID:23578259

Yuan, Jiangtan; Ma, Lai-Peng; Pei, Songfeng; Du, Jinhong; Su, Yang; Ren, Wencai; Cheng, Hui-Ming

2013-05-28

250

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

PubMed

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

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

2013-03-01

251

Silver nanowires for transparent conductive electrode to GaN-based light-emitting diodes  

NASA Astrophysics Data System (ADS)

Transparent, conductive, and uniform Ag nanowires (NWs) were introduced to improve the optical performance of GaN-based light-emitting diodes (LEDs) by a spin-coating technique. The Ag NWs acted as a current spreading layer, exhibiting high transmittance and low sheet resistance, and ultimately leading to high performance GaN-based LEDs with an ultra large size of 5 5 mm2. Compared to the transmittance of conventional LEDs without Ag NWs, the relative transmittance of LEDs with Ag NWs was approximately 90% of the overall wavelength region. However, the electroluminescence (EL) intensity of LED with Ag NWs was much higher than that of conventional LEDs without Ag NWs for injection current above 45 mA. In addition, the EL full width at half maximum of LEDs with Ag NWs was much lower than that of conventional LEDs without Ag NWs. Based on these results, we believe that the enhanced optical performance of ultra large LEDs was due to an increase in the current spreading effect.

Jeong, Gyu-Jae; Lee, Jae-Hwan; Han, Sang-Hyun; Jin, Won-Yong; Kang, Jae-Wook; Lee, Sung-Nam

2015-01-01

252

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

253

TiN nanoparticles on CNT-graphene hybrid support as noble-metal-free counter electrode for quantum-dot-sensitized solar cells.  

PubMed

The development of an efficient noble-metal-free counter electrode is crucial for possible applications of quantum-dot-sensitized solar cells (QDSSCs). Herein, we present TiN nanoparticles on a carbon nanotube (CNT)-graphene hybrid support as a noble-metal-free counter electrode for QDSSCs employing a polysulfide electrolyte. The resulting TiN/CNT-graphene possesses an extremely high surface roughness, a good metal-support interaction, and less aggregation relative to unsupported TiN; it also has superior solar power conversion efficiency (4.13 %) when applying a metal mask, which is much higher than that of the state-of-the-art Au electrode (3.35 %). Based on electrochemical impedance spectroscopy measurements, the enhancement is ascribed to a synergistic effect between TiN nanoparticles and the CNT-graphene hybrid, the roles of which are to provide active sites for the reduction of polysulfide ions and electron pathways to TiN nanoparticles, respectively. The combination of graphene and CNTs leads to a favorable morphology that prevents stacking of graphene or bundling of CNTs, which maximizes the contact of the support with TiN nanoparticles and improves electron-transfer capability relative to either carbon material alone. PMID:23303691

Youn, Duck Hyun; Seol, Minsu; Kim, Jae Young; Jang, Ji-Wook; Choi, Youngwoo; Yong, Kijung; Lee, Jae Sung

2013-02-01

254

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

255

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

256

Zinc Oxide and Iron Phthalocyanine(FePc) based Hybrid Inorganic-Organic p-n Junction Diode Using Heavily Doped Zinc Oxide Transparent Conducting Electrode  

Microsoft Academic Search

We report on the fabrication of FePc\\/ZnO hybrid p-n junction device using Aluminum doped zinc oxide (AZO) as the transparent conducting electrode. The structure of such devices consist of ZnO and an organic molecular semiconductors, in which ZnO and Organic thin films served as n and p-type component respectively. We have obtained a rectification factor greater than ~102 and current

Budhi Singh; Subhasis Ghosh

2011-01-01

257

Gravure printed hydrophobic templates onto PET films for guiding the assembly of nanowires: Towards the ultralow-cost transparent conductive electrodes  

Microsoft Academic Search

We present our work of fabricating silver nanowires (Ag NWs) network with regularity and homogeneity as the transparent conductive electrodes for optoelectronic applications. Though patterning hydrophobic materials (e.g. PDMS) onto the substrate (polyethylene terephthalate (PET)) surface, we are able to adjust the surface energy level between the patterned and un-patterned area, which is crucial to the wetting\\/dewetting of the solution

Wayman N. M. Wong; Cheng Yang; Matthew M. F. Yuen

2011-01-01

258

An ultrathin, smooth, and low-loss Al-doped Ag film and its application as a transparent electrode in organic photovoltaics.  

PubMed

An ultrathin, smooth, and low-loss Ag film without a wetting layer is achieved by co-depositing a small amount of Al into Ag. The film can be as thin as 6 nm, with a roughness below 1 nm and excellent mechanical flexibility. Organic photovoltaics that use these thin films as transparent electrode show superior efficiency to their indium tin oxide (ITO) counterparts because of improved photon management. PMID:24943876

Zhang, Cheng; Zhao, Dewei; Gu, Deen; Kim, Hyunsoo; Ling, Tao; Wu, Yi-Kuei Ryan; Guo, L Jay

2014-08-27

259

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

Microsoft Academic Search

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

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

2011-01-01

260

Comparison of the dye-sensitized solar cells performances based on transparent conductive ITO and FTO  

Microsoft Academic Search

We investigated dye-sensitized solar cell (DSSC) performances with regard to transparent conducting oxide substrates: indium-doped tin oxide (ITO) and fluorine-doped tin oxide (FTO). The DSSCs were in a standard configuration: a photoelectrode of TiO2 nanoparticles (9nm size, anatase phase) deposited on transparent and electrically conductive substrates, counter electrodes of Pt-coated glass, ruthenium 535 dye, and AN50 iodolyte electrolyte (Solaronix). The

Cornelia Sima; Constantin Grigoriu; Stefan Antohe

2010-01-01

261

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

SciTech Connect

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, E-mail: wucc@ntu.edu.tw [Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, Graduate Institute of Electronics Engineering, and Innovative Photonics Advanced Research Center (i-PARC), National Taiwan University, Taipei 10617, Taiwan (China)

2014-05-05

262

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

263

Using modified poly(3,4-ethylene dioxythiophene): Poly(styrene sulfonate) film as a counter electrode in dye-sensitized solar cells  

Microsoft Academic Search

Dye-sensitized solar cells (DSSCs), assembling with nano-crystalline TiO2 adsorbed cis-Ru(dcb)2(NCS)2 dye (known as N3) using polar solvent-treated poly(3,4-ethylene dioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) coating on a conductive glass (fluorine-doped tin oxide, FTO) as a counter electrode, were studied. The conductivity of a bare PEDOT:PSS film was only 20.05S\\/cm. However, the conductivities of PEDOT:PSS films treated with dimethyl sulfoxide (DMSO), N,N-dimethyl acetamide

Jian-Ging Chen; Hung-Yu Wei; Kuo-Chuan Ho

2007-01-01

264

The Role of Mott-Schottky Heterojunctions in Ag-Ag8 SnS6 as Counter Electrodes in Dye-Sensitized Solar Cells.  

PubMed

Well-defined uniform pyramidal Ag-Ag8 SnS6 heterodimers are prepared via a one-pot method. A plausible formation mechanism for the unique structures based on a seed-growth process and an etching effect due to oleylamine is proposed. The formed metal-semiconductor Mott-Schottky heterojunction promotes electron transfer from semiconducting Ag8 SnS6 to metallic Ag, which catalyzes the reduction of I3 (-) to I(-) . When used as counter electrode in dye-sensitized solar cells, the heterodimers show comparable performance to platinum. PMID:25619568

He, Qingquan; Huang, Shoushuang; Wang, Cheng; Qiao, Qiquan; Liang, Na; Xu, Miao; Chen, Wenlong; Zai, Jiantao; Qian, Xuefeng

2015-03-01

265

Large-scale synthesis of Cu2SnS3 and Cu(1.8)S hierarchical microspheres as efficient counter electrode materials for quantum dot sensitized solar cells.  

PubMed

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 Cu(2)SnS(3) (CTS) and rhombohedral Cu(1.8)S 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 (S(n)(2-)/S(2-)) 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 Cu(1.8)S microspheres. This contributes to obvious enhancement of photocurrent density (J(SC)) and fill factor (FF). Power conversion efficiency (PCE) is significantly enhanced from 0.25% for the cell using a pure FTO (SnO(2):F) glass as counter electrode, to 3.65 and 4.06% for the cells using counter electrodes of FTO glasses coated respectively with Cu(1.8)S and CTS microspheres. PMID:22968176

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

2012-10-21

266

Well-dispersed CoS nanoparticles on a functionalized graphene nanosheet surface: a counter electrode of dye-sensitized solar cells.  

PubMed

With a facile electrophoretic deposition and chemical bath process, CoS nanoparticles have been uniformly dispersed on the surface of the functionalized graphene nanosheets (FGNS). The composite was employed as a counter electrode of dye-sensitized solar cells (DSSCs), which yielded a power conversion efficiency of 5.54?%. It is found that this efficiency is higher than those of DSSCs based on the non-uniform CoS nanoparticles on FGNS (4.45?%) and built on the naked CoS nanoparticles (4.79?%). The achieved efficiency of our cost-effective DSSC is also comparable to that of noble metal Pt-based DSSC (5.90?%). Our studies have revealed that both the exceptional electrical conductivity of the FGNS and the excellent catalytic activity of the CoS nanoparticles improve the conversion efficiency of the uniformly FGNS-CoS composite counter electrode. The electrochemical impedance spectra, cyclic voltammetry, and Tafel polarization have evidenced the best catalytic activity and the fastest electron transport. Additionally, the dispersion condition of CoS nanoparticles on FGNS plays an important role for catalytic reduction of I3 (-) . PMID:24307511

Miao, Xiaohuan; Pan, Kai; Wang, Guofeng; Liao, Yongping; Wang, Lei; Zhou, Wei; Jiang, Baojiang; Pan, Qingjiang; Tian, Guohui

2014-01-01

267

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

268

Rapid charge-transfer in polypyrrole-single wall carbon nanotube complex counter electrodes: Improved photovoltaic performances of 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 clean, high efficiency, good durability, and easy fabrication. However, enhancement of power conversion efficiency and high cost of Pt counter electrode are still significant issues in commercial application of DSSCs. Herein, pyrrole-single wall nanotube (pyrrole-SWCNT) complexes are pioneerly synthesized by a reflux technique and subsequently in-situ polymerized and employed as counter electrodes (CEs) for DSSCs. Different from traditional polypyrrole/SWCNT (PPy/SWCNT) composites, the resultant PPy-SWCNT complexes are expected to fulfill the good electrical-conduction of SWCNT and electrocatalytic behaviors of PPy in accelerating electrochemical activity and charge transfer owing to the covalent bond between PPy (N atoms) and SWCNT (C atoms). The DSSCs employing PPy-SWCNT complex CEs exhibit significantly enhanced photovoltaic performances, in which a promising power conversion efficiency of 8.30% is obtained from PPy-2wt SWCNT complex CE in comparison with 6.31% from PPy-only CE. The high conversion efficiency, rapid charge-transfer in combination with simple preparation, relatively low cost, and scalability demonstrates the potential use of PPy-SWCNT complexes in robust DSSCs.

He, Benlin; Tang, Qunwei; Luo, Jinghuan; Li, Qinghua; Chen, Xiaoxu; Cai, Hongyuan

2014-06-01

269

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

270

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

271

Indium tin oxide-free transparent and conductive electrode based on SnOx | Ag | SnOx for organic solar cells  

NASA Astrophysics Data System (ADS)

A SnOx | Ag | SnOx multilayer deposited by E-beam evaporation is proposed as transparent anode for a (poly-3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk heterojunction based Organic Solar Cell (OSC). Such multilayers are studied and manufactured with the objective to give to the electrode its best conductivity and transparency in the visible spectral range. A transfer matrix method numerical optimization of the thicknesses of each layer of the electrode is developed to limit the number of test samples which would have been manufactured whether an empirical method was chosen. Optical characterization of the deposited SnOx and Ag thin films is performed to determine the dispersion of the complex refractive indices which are used as input parameters in the model. A satisfying agreement between numerical and experimental optical properties is found. The bare tri-layer electrodes show low sheet resistance (as low as 6.7 ?/?) and the whole Glass | SnOx | Ag | SnOx structure presents a mean transparency on 400-700 nm spectral band as high as 67%. The multilayer is then numerically studied as anode for a P3HT:PCBM bulk heterojunction based OSC. Intrinsic absorption inside the sole active layer is calculated giving the possibility to perform optical optimization on the intrinsic absorption efficiency inside the active area by considering the media embedding the electrodes. An additional study using the morphology of the silver inserted between both oxide layers as input data is performed with a finite difference time domain 3D-method to improve the accordance between optical measurements and numerical results.

Bou, A.; Torchio, Ph.; Barakel, D.; Thierry, F.; Sangar, A.; Thoulon, P.-Y.; Ricci, M.

2014-07-01

272

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

273

Healable capacitive touch screen sensors based on transparent composite electrodes comprising silver nanowires and a furan/maleimide diels-alder cycloaddition polymer.  

PubMed

A healable transparent capacitive touch screen sensor has been fabricated based on a healable silver nanowire-polymer composite electrode. The composite electrode features a layer of silver nanowire percolation network embedded into the surface layer of a polymer substrate comprising an ultrathin soldering polymer layer to confine the nanowires to the surface of a healable Diels-Alder cycloaddition copolymer and to attain low contact resistance between the nanowires. The composite electrode has a figure-of-merit sheet resistance of 18 ?/sq with 80% transmittance at 550 nm. A surface crack cut on the conductive surface with 18 ? is healed by heating at 100 C, and the sheet resistance recovers to 21 ? in 6 min. A healable touch screen sensor with an array of 88 capacitive sensing points is prepared by stacking two composite films patterned with 8 rows and 8 columns of coupling electrodes at 90 angle. After deliberate damage, the coupling electrodes recover touch sensing function upon heating at 80 C for 30 s. A capacitive touch screen based on Arduino is demonstrated capable of performing quick recovery from malfunction caused by a razor blade cutting. After four cycles of cutting and healing, the sensor array remains functional. PMID:25486240

Li, Junpeng; Liang, Jiajie; Li, Lu; Ren, Fengbo; Hu, Wei; Li, Juan; Qi, Shuhua; Pei, Qibing

2014-12-23

274

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

275

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

PubMed

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 ? cm(2), while those of a NiO-NP-immobilized electrode and a GO-coated electrode were 44.39 ? cm(2) and 12.19 ? cm(2), respectively, due to a synergistic effect. PMID:24217311

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

2014-01-01

276

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

277

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

278

In situ synthesis of a NiS/Ni3S2 nanorod composite array on Ni foil as a FTO-free counter electrode for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

A NiS/Ni3S2 nanorod composite array that directly grows on Ni foil has been used as a counter electrode for dye-sensitized solar cells; these nickel sulfide nanorods exhibit excellent photo-electrical conversion efficiency when compared with conventional noble-metal Pt electrodes.A NiS/Ni3S2 nanorod composite array that directly grows on Ni foil has been used as a counter electrode for dye-sensitized solar cells; these nickel sulfide nanorods exhibit excellent photo-electrical conversion efficiency when compared with conventional noble-metal Pt electrodes. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr06534d

Liao, Yongping; Pan, Kai; Pan, Qingjiang; Wang, Guofeng; Zhou, Wei; Fu, Honggang

2015-01-01

279

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

280

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

281

Notable catalytic activity of oxygen-vacancy-rich WO(2.72) nanorod bundles as counter electrodes for dye-sensitized solar cells.  

PubMed

For the first time, nonstoichiometric WO2.72 was used as a counter electrode (CE) in dye-sensitized solar cells (DSSCs). Oxygen-vacancy-rich WO2.72 nanorod bundles with notable catalytic activity for triiodide and thiolate reduction were prepared in this study. The photovoltaic parameters of dye-sensitized solar cells (DSSCs) with WO2.72 nanorod bundles as CEs are superior compared with those of the WO3-based cells, and nearly the same as those of the precious metal Pt-based cells. In a non-corrosive organic redox couple, the performance of WO2.72 CEs is better than that of Pt and WO3 CEs in DSSCs. PMID:23872931

Zhou, Huawei; Shi, Yantao; Wang, Liang; Zhang, Hong; Zhao, Chunyu; Hagfeldt, Anders; Ma, Tingli

2013-09-01

282

Photovoltaic performance of multi-wall carbon nanotube/PEDOT:PSS composite on the counter electrode of a dye-sensitized solar cell  

NASA Astrophysics Data System (ADS)

A composite of poly(3,4-ethylendioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and multi-walled carbon nanotubes (MWCNTs) was cyclovoltametrically electropolymerized on a fluorine-doped tin oxide (FTO) substrate and used as a counter electrode for a dye-sensitized solar cell. The PEDOT:PSS-MWCNT composite film was investigated using scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The CV diagrams showed that the PEDOT:PSS-MWCNT composite film has better electro-catalytic activity for the I-/I3- redox reaction than the conventional platinized FTO. The best energy conversion efficiency was observed in EIS data with an MWCNT content of 0.002 wt %.

Rhee, Yonghoon; Ko, Minjae; Jin, Hwayoung; Jin, Joon-Hyung; Min, Nam Ki

2014-08-01

283

The maximum limiting performance improved counter electrode based on a porous fluorine doped tin oxide conductive framework for dye-sensitized solar cells.  

PubMed

A novel porous fluorine doped tin oxide (PFTO) conductive framework was introduced to counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). When modified by platinum (Pt) or carbon (C), the PFTO conductive framework displays high catalytic activity to I(-)/I3(-) redox couples. Power conversion efficiencies of 6.09% and 5.81% were obtained in the DSSCs based on Pt and C modified PFTO CEs respectively, which were close to that of DSSCs with Pt coated FTO glass (6.05%) and Pt sheet (6.26%) CEs. Maximum limiting performances of the CEs were obtained from the polarization curves. The CE based on PFTO showed higher maximum limiting power conversion efficiency (~20%) compared with the planar FTO substrate Pt CE (~18%), with the increase of its surface area and electrocatalytic activity. PMID:23632829

Bao, Chunxiong; Huang, Huan; Yang, Jie; Gao, Hao; Yu, Tao; Liu, Jianguo; Zhou, Yong; Li, Zhaosheng; Zou, Zhigang

2013-06-01

284

Novel two-step synthesis of NiS nanoplatelet arrays as efficient counter electrodes for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Platinum-free (Pt-free) counter electrodes (CEs) can reduce the cost of dye-sensitized solar cells (DSCs). In this study, a general strategy is proposed to construct Pt-free CEs, namely direct growth of electrocatalytic active nanostructures (metal sulfide, etc.) on conductive substrates via low temperature solution routes. As an implementation, nickel sulfide (NiS) nanoarray film composed of interconnected nanoplatelets is successfully fabricated by a two-step solution route. The as-grown NiS nanoarray film follows the sulfurization process in a thiourea aqueous solution from the precursor of hydrothermally deposited Ni(OH)2 nanoplatelet arrays on FTO substrates. When applied as a Pt-free CE in DSCs, a maximum power conversion efficiency of 7.10% is achieved, comparable to that of Pt CE (7.35%).

Zhao, Wei; Zhu, Xiaolong; Bi, Hui; Cui, Houlei; Sun, Shengrui; Huang, Fuqiang

2013-11-01

285

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

PubMed

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

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

2013-04-24

286

Self-assembled free-standing polypyrrole nanotube membrane as an efficient FTO- and Pt-free counter electrode for dye-sensitized solar cells.  

PubMed

The construction of nanoporous conductive polymer membranes has potential applications in catalysts and energy-conversion devices. In this letter, we present a facile method to prepare free-standing polypyrrole (PPy) nanotube films by simply heating pulp-like homogeneous suspensions at a low temperature, which can be employed as a novel counter electrode (CE) to substitute for the expensive fluorine-doped tin oxide (FTO) glass and Pt used in dye-sensitized solar cells (DSSCs). The DSSCs assembled with these paper-like PPy membranes show an impressive conversion efficiency of 5.27%, which is about 84% of the cell with a conventional Pt/FTO CE (6.25%). PMID:24341831

Peng, Tao; Sun, Weiwei; Huang, Chengliang; Yu, Wenjing; Sebo, Bobby; Dai, Zhigao; Guo, Shishang; Zhao, Xing-Zhong

2014-01-01

287

Composite counter electrode based on nanoparticulate PbS and carbon black: towards quantum dot-sensitized solar cells with both high efficiency and stability.  

PubMed

PbS/carbon black (CB) composite counter electrode (CE) has been fabricated by a low cost and low temperature processable method using the wet chemistry synthesized PbS nanoparticles. The nanosized PbS in the composite CE provides a large area of catalytic sites, and the chain-type CB framework acts as an excellent electrical tunnel for fast electron transport from an external circuit to highly catalytic PbS nanoparticles. The optimized PbS/CB composite CE shows a charge transfer resistance (R(CT)) as low as 10.28 ? cm, which is an order of magnitude lower than the value obtained in the previous study on pure PbS CE. The CdS/CdSe quantum dot-sensitized solar cells with the PbS/CB composite CE achieve a photovoltaic conversion efficiency of 3.91% and no degradation of the efficiency over 1000 h under room conditions. PMID:23075399

Yang, Yueyong; Zhu, Lifeng; Sun, Huicheng; Huang, Xiaoming; Luo, Yanhong; Li, Dongmei; Meng, Qingbo

2012-11-01

288

Cost-effective dye-sensitized solar cells consisting of two metal foils instead of transparent conductive oxide glass.  

PubMed

A cost-effective structure for dye-sensitized solar cells (DSSCs) without using transparent conductive oxide (TCO) is reported. Instead of high-cost F/SnO(2) glass (FTO-glass) or woven metal mesh, a Ti foil and a perforation-patterned stainless steel (StSt) foil are introduced as the substrates for a counter-electrode and a photo-electrode, respectively. PMID:22466304

Yun, Ho-Gyeong; Kim, Myoung; Kang, Man Gu; Lee, In-Hwan

2012-05-14

289

A spray-coating process for highly conductive silver nanowire networks as the transparent top-electrode for small molecule organic photovoltaics  

NASA Astrophysics Data System (ADS)

We present a novel top-electrode spray-coating process for the solution-based deposition of silver nanowires (AgNWs) onto vacuum-processed small molecule organic electronic solar cells. The process is compatible with organic light emitting diodes (OLEDs) and organic light emitting thin film transistors (OLETs) as well. By modifying commonly synthesized AgNWs with a perfluorinated methacrylate, we are able to disperse these wires in a highly fluorinated solvent. This solvent does not dissolve most organic materials, enabling a top spray-coating process for sensitive small molecule and polymer-based devices. The optimized preparation of the novel AgNW dispersion and spray-coating at only 30 C leads to high performance electrodes directly after the deposition, exhibiting a sheet resistance of 10.0 ? ?-1 at 87.4% transparency (80.0% with substrate). By spraying our novel AgNW dispersion in air onto the vacuum-processed organic p-i-n type solar cells, we obtain working solar cells with a power conversion efficiency (PCE) of 1.23%, compared to the air exposed reference devices employing thermally evaporated thin metal layers as the top-electrode.We present a novel top-electrode spray-coating process for the solution-based deposition of silver nanowires (AgNWs) onto vacuum-processed small molecule organic electronic solar cells. The process is compatible with organic light emitting diodes (OLEDs) and organic light emitting thin film transistors (OLETs) as well. By modifying commonly synthesized AgNWs with a perfluorinated methacrylate, we are able to disperse these wires in a highly fluorinated solvent. This solvent does not dissolve most organic materials, enabling a top spray-coating process for sensitive small molecule and polymer-based devices. The optimized preparation of the novel AgNW dispersion and spray-coating at only 30 C leads to high performance electrodes directly after the deposition, exhibiting a sheet resistance of 10.0 ? ?-1 at 87.4% transparency (80.0% with substrate). By spraying our novel AgNW dispersion in air onto the vacuum-processed organic p-i-n type solar cells, we obtain working solar cells with a power conversion efficiency (PCE) of 1.23%, compared to the air exposed reference devices employing thermally evaporated thin metal layers as the top-electrode. Electronic supplementary information (ESI) available: XPS and SEM data clarifying the crucial role of the amount of stabilizer on sheet resistance; j-V-data of the annealed air cell enabling a deeper understanding of the influence of air exposure. See DOI: 10.1039/c4nr06502f.

Selzer, Franz; Wei, Nelli; Kneppe, David; Bormann, Ludwig; Sachse, Christoph; Gaponik, Nikolai; Eychmller, Alexander; Leo, Karl; Mller-Meskamp, Lars

2015-01-01

290

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

291

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

292

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

PubMed Central

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

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

2013-01-01

293

Development of Carbon Based optically Transparent Electrodes from Pyrolyzed Photoresist for the Investigation of Phenomena at Electrified Carbon-Solution Interfaces  

SciTech Connect

The work presented herein describes a fundamental investigations of carbon as electrode material by using the pyrolysis of photoresist to create an optically transparent material. The development of these carbon-based optically transparent electrodes (C-OTEs) enables investigations of molecular interactions within the electrical double layer, processes that are central to a wide range of important phenomena, including the impact of changes in the surface charge density on adsorption. The electrochemical importance of carbon cannot be understated, having relevance to separations and detection by providing a wide potential window and low background current in addition to being low cost and light weight. The interactions that govern the processes at the carbon electrode surface has been studied extensively. A variety of publications from the laboratories of McCreery and Kinoshita provide in depth summaries about carbon and its many applications in electrochemistry. These studies reveal that defects, impurities, oxidation, and a variety of functional groups create adsorption sites on carbon surfaces with different characteristics. The interest in C-OTEs was sparked by the desire to study and understand the behavior of individual molecules at electrified interfaces. It draws on the earlier development of Electrochemically Modulated Liquid Chromatography (EMLC), which uses carbon as the stationary phase. EMLC takes advantage of changing the applied potential to the carbon electrode to influence the retention behavior of analytes. However, perspectives gained from, for example, chromatographic measurements reflect the integrated response of a large ensemble of potentially diverse interactions between the adsorbates and the carbon electrode. Considering the chemically and physically heterogeneous surface of electrode materials such as glassy carbon, the integrated response provides little insight into the interactions at a single molecule level. To investigate individual processes, they have developed C-OTEs in order to couple electrochemistry with single molecule spectroscopy (SMS). Like EMLC, the novel merger of SMS with electrochemistry is a prime example of how a hybrid method can open new and intriguing avenues that are of both fundamental and technological importance. They show that by taking the benefits of total internal reflection fluorescence microscopy (TIRFM) and incorporating carbon as electrode material observations central to the interactions between single DNA molecules and an electrified carbon surface can be delineated. Using TIRFM while applying a positive potential to the electrode, individual molecules can be observed as they reversibly and irreversibly adsorb to the carbon surface. The positive potential attracts the negatively charged DNA molecules to the electrode surface. Dye labels on the DNA within the evanescent wave are excited and their fluorescence is captured by an intensified charge coupled device (ICCD) camera. Results are therefore presented regarding the interactions of {lambda}-DNA, 48,502 base pairs (48.5 kbp), HPV-16, 7.9 kbp, and 1 kbp fraction of pBR322 DNA. In addition to the influence of molecular size on adsorption, the fabrication, characterization, and more conventional spectroelectrochemical applications of these novel C-OTEs are presented.

Sebastian Donner

2007-12-01

294

Effect of purity on the electro-optical properties of single wall nanotube-based transparent conductive electrodes 5  

E-print Network

Effect of purity on the electro-optical properties of single wall nanotube-based transparent purification techniques are multi-step pro- cedures, which include a combination of acid reflux, oxida- tion Van der Waals interactions, and hard to disperse without additional surface functionalization

Geohegan, David B.

295

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

SciTech Connect

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

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

1996-08-01

296

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

297

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

NASA Astrophysics Data System (ADS)

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.

Kim, Ji-Hong; Lee, Kyung-Ju; Roh, Ji-Hyung; Song, Sang-Woo; Park, Jae-Ho; Yer, In-Hyung; Moon, Byung-Moo

2012-01-01

298

Characteristic difference between ITO/ZrCu and ITO/Ag bi-layer films as transparent electrodes deposited on PET substrate  

NASA Astrophysics Data System (ADS)

The metallic-glass film of ZrCu layer deposited by co-sputtering was utilized as the metallic layer in the bi-layer structure transparent conductive electrode of ITO/ZrCu (IZC) deposited on the PET substrate using magnetron sputtering at room temperature. In addition, the pure Ag metal layer was applied in the same structure of transparent conductive film, ITO/Ag, in comparison with the IZC film. The ZrCu layer could form a continuous and smooth film in thickness lower than 6 nm, compared with the island structure of pure Ag layer of the same thickness. The 30 nm ITO/3 nm ZrCu films could show the optical transmittance of 73% at 550 nm wavelength. The 30 nm ITO/12 nm ZrCu films could show the better sheet resistance of 20 ?/sq, but it was still worse than that of the ITO/Ag films. It was suggested that an alloy system with lower resistivity and negative mixing heat between atoms might be another way to form a continuous layer in thickness lower than 6 nm for metal film.

Lee, C. J.; Lin, H. K.; Sun, S. Y.; Huang, J. C.

2010-10-01

299

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

300

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

301

One-step synthesis of stoichiometric Cu2ZnSnSe4 as counter electrode for dye-sensitized solar cells.  

PubMed

Cu(2)ZnSnSe(4) (CZTSe) nanoparticles with diameters of 200-300 nm were synthesized by one-step solvothermal method without surfactants or templates. The structure, composition and morphology of CZTSe nanoparticles were characterized by XRD, XPS, Raman spectrum, EDS, FESEM and TEM. The results indicated that the nanoparticles were single phase and nearly stoichiometric composition. CZTSe nanoparticles drop-casted onto FTO substrate were used as counter electrode (CE) in dye-sensitized solar cells (DSSCs) for the first time, which exhibited Pt-like electrocatalytic activity for the reduction of I(3)(-) to I(-) in DSSCs. The J-V results demonstrated that the thickness of the film affected the photocurrent density and fill factor remarkably, which resulted from the difference of electrocatalytic sites and resistance with different thickness films. And a best efficiency of 3.85% was obtained by adjusting the film thickness. The work presents a new approach for developing low-cost, facile fabrication CZTSe nanoparticles, and demonstrates CZTSe can be explored as a low-cost alternative for expensive and scare Pt in DSSCs. PMID:22387625

Du, Yan-Fang; Fan, Jun-Qi; Zhou, Wen-Hui; Zhou, Zheng-Ji; Jiao, Jie; Wu, Si-Xin

2012-03-01

302

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

303

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

PubMed

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

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

2014-01-01

304

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

305

Effect of crystallization of Cu?ZnSnSxSe?-x counter electrode on the performance for efficient dye-sensitized solar cells.  

PubMed

Cu2ZnSnSxSe4-x (CZTSSe) counter electrodes (CEs) in dye-sensitized solar cells (DSSCs) are commonly developed with porous structures, but their high surface area could also retard electron transport processes owing to the abundant grain boundaries. Herein, we employed a convenient solution method and a rapid heating process to prepare well crystalline CZTSSe CEs in DSSCs. The influence of crystallization of CZTSSe film on DSSCs performances was discussed in depth. The thermogravimetric analysis, phase morphology, conductivity, and electrochemical characteristics of CZTSSe films were performed. It is found that the rapid heating process is beneficial to the formation of well crystalline film with large grains. As the porosity and grain boundaries in the bulk film are dramatically reduced with the enhanced crystallization, the charge transport process is gradually improved. Using cyclic voltammogram and electrochemical impedance spectroscopy measurements, we propose that the accelerating charge transport is of great importance to the photovoltaic performances of DSSCs due to their superior electrocatalytic activities. As the highest cell efficiency was achieved, well crystalline CZTSSe is an efficient CE catalytic material. PMID:25382857

Chen, Hongli; Kou, Dongxing; Chang, Zhixian; Zhou, Wenhui; Zhou, Zhengji; Wu, Sixin

2014-12-10

306

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

307

High performance electrocatalyst consisting of CoS nanoparticles on an organized mesoporous SnO2 film: its use as a counter electrode for Pt-free, dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

High energy conversion efficiencies of 6.6% and 7.5% are demonstrated in solid and liquid states, Pt-free, dye-sensitized solar cells (DSSCs), respectively, based on CoS nanoparticles on an organized mesoporous SnO2 (om-SnO2) counter electrode. These results correspond to improvements of 14% and 9%, respectively, compared to a conventional Pt counter electrode and are among the highest values reported for Pt-free DSSCs. The om-SnO2 layer plays a pivotal role as a platform to deposit a large amount of highly electrocatalytically active CoS nanoparticles via a facile solvothermal reaction. The om-SnO2 platform with a high porosity, larger pores, and good interconnectivity is derived from a poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) graft copolymer template, which provides not only improved interaction sites for the formation of CoS nanoparticles but also enhanced electron transport. The structural, morphological, chemical, and electrochemical properties of CoS on the om-SnO2 platform are investigated using field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) measurements. The performance enhancement results from the excellent electron transport at the fluorine-doped tin oxide (FTO)/counter electrode/electrolyte interface, reduced resistance at the FTO/CoS interface, and better catalytic reduction at the counter electrode/electrolyte interface.High energy conversion efficiencies of 6.6% and 7.5% are demonstrated in solid and liquid states, Pt-free, dye-sensitized solar cells (DSSCs), respectively, based on CoS nanoparticles on an organized mesoporous SnO2 (om-SnO2) counter electrode. These results correspond to improvements of 14% and 9%, respectively, compared to a conventional Pt counter electrode and are among the highest values reported for Pt-free DSSCs. The om-SnO2 layer plays a pivotal role as a platform to deposit a large amount of highly electrocatalytically active CoS nanoparticles via a facile solvothermal reaction. The om-SnO2 platform with a high porosity, larger pores, and good interconnectivity is derived from a poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) graft copolymer template, which provides not only improved interaction sites for the formation of CoS nanoparticles but also enhanced electron transport. The structural, morphological, chemical, and electrochemical properties of CoS on the om-SnO2 platform are investigated using field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) measurements. The performance enhancement results from the excellent electron transport at the fluorine-doped tin oxide (FTO)/counter electrode/electrolyte interface, reduced resistance at the FTO/CoS interface, and better catalytic reduction at the counter electrode/electrolyte interface. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05779a

Park, Jung Tae; Lee, Chang Soo; Kim, Jong Hak

2014-12-01

308

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

309

Zinc Oxide Modified with Benzylphosphonic Acids as Transparent Electrodes in Regular and Inverted Organic Solar Cell Structures  

E-print Network

An approach is presented to modify the WF of solution-processed sol-gel derived ZnOover an exceptionally wide range of more than 2.3 eV. This approach relies on the formation of dense and homogeneous self-assembled monolayers based on phosphonic acids with different dipole moments. This allows us to apply ZnO as charge selective bottom electrodes in either regular or inverted solar cell structures, using P3HT:PCBM as the active layer. These devices compete with or even exceed the performance of the reference cell on ITO/PEDOT:PSS. Our finding challenges the current view that bottom electrodes in inverted solar cells need to be electron-blocking for good device performance.

Ilja Lange; Sina Reiter; Juliane Kniepert; Fortunato Piersimoni; Michael Paetzel; Jana Hildebrandt; Thomas Brenner; Stefan Hecht; Dieter Neher

2015-02-05

310

Zinc oxide modified with benzylphosphonic acids as transparent electrodes in regular and inverted organic solar cell structures  

NASA Astrophysics Data System (ADS)

An approach is presented to modify the work function of solution-processed sol-gel derived zinc oxide (ZnO) over an exceptionally wide range of more than 2.3 eV. This approach relies on the formation of dense and homogeneous self-assembled monolayers based on phosphonic acids with different dipole moments. This allows us to apply ZnO as charge selective bottom electrodes in either regular or inverted solar cell structures, using poly(3-hexylthiophene):phenyl-C71-butyric acid methyl ester as the active layer. These devices compete with or even surpass the performance of the reference on indium tin oxide/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate. Our findings highlight the potential of properly modified ZnO as electron or hole extracting electrodes in hybrid optoelectronic devices.

Lange, Ilja; Reiter, Sina; Kniepert, Juliane; Piersimoni, Fortunato; Ptzel, Michael; Hildebrandt, Jana; Brenner, Thomas; Hecht, Stefan; Neher, Dieter

2015-03-01

311

High performance electrocatalyst consisting of CoS nanoparticles on an organized mesoporous SnO2 film: its use as a counter electrode for Pt-free, dye-sensitized solar cells.  

PubMed

High energy conversion efficiencies of 6.6% and 7.5% are demonstrated in solid and liquid states, Pt-free, dye-sensitized solar cells (DSSCs), respectively, based on CoS nanoparticles on an organized mesoporous SnO2 (om-SnO2) counter electrode. These results correspond to improvements of 14% and 9%, respectively, compared to a conventional Pt counter electrode and are among the highest values reported for Pt-free DSSCs. The om-SnO2 layer plays a pivotal role as a platform to deposit a large amount of highly electrocatalytically active CoS nanoparticles via a facile solvothermal reaction. The om-SnO2 platform with a high porosity, larger pores, and good interconnectivity is derived from a poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) graft copolymer template, which provides not only improved interaction sites for the formation of CoS nanoparticles but also enhanced electron transport. The structural, morphological, chemical, and electrochemical properties of CoS on the om-SnO2 platform are investigated using field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) measurements. The performance enhancement results from the excellent electron transport at the fluorine-doped tin oxide (FTO)/counter electrode/electrolyte interface, reduced resistance at the FTO/CoS interface, and better catalytic reduction at the counter electrode/electrolyte interface. PMID:25429695

Park, Jung Tae; Lee, Chang Soo; Kim, Jong Hak

2015-01-14

312

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

2014-11-26

313

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

SciTech Connect

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

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

2006-05-01

314

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

Microsoft Academic Search

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

J. van de Lagemaat; T. Barnes; G. Rumbles; S. Shaheen; T. J. Coutts; P. Glatkowski; I. Levitsky; J. Peltola

2006-01-01

315

Catalytic, conductive, and transparent platinum nanofiber webs for FTO-free dye-sensitized solar cells.  

PubMed

We report a multifunctional platinium nanofiber (PtNF) web that can act as a catalyst layer in dye-sensitized solar cell (DSSC) to simultaneously function as a transparent counter electrode (CE), i.e., without the presence of an indium-doped tin oxide (ITO) or fluorine-doped tin oxide (FTO) glass. This PtNF web can be easily produced by electrospinning, which is highly cost-effective and suitable for large-area industrial-scale production. Electrospun PtNFs are straight and have a length of a few micrometers, with a common diameter of 40-70 nm. Each nanofiber is composed of compact, crystalline Pt grains and they are well-fused and highly interconnected, which should be helpful to provide an efficient conductive network for free electron transport and a large surface area for electrocatalytic behavior. A PtNF web is served as a counter electrode in DSSC and the photovoltaic performance increases up to a power efficiency of 6.0%. It reaches up to 83% of that in a conventional DSSC using a Pt-coated FTO glass as a counter electrode. Newly designed DSSCs containing PtNF webs display highly stable photoelectric conversion efficiencies, and excellent catalytic, conductive, and transparent properties, as well as long-term stability. Also, while the DSSC function is retained, the fabrication cost is reduced by eliminating the transparent conducting layer on the counter electrode. The presented method of fabricating DSSCs based on a PtNF web can be extended to other electrocatalytic optoelectronic devices that combine superior catalytic activity with high conductivity and transparency. PMID:23517275

Kim, Jongwook; Kang, Jonghyun; Jeong, Uiyoung; Kim, Heesuk; Lee, Hyunjung

2013-04-24

316

Efficient p-type dye-sensitized solar cells with all-nano-electrodes: NiCo2S4 mesoporous nanosheet counter electrodes directly converted from NiCo2O4 photocathodes  

PubMed Central

We report the successful growth of NiCo2S4 nanosheet films converted from NiCo2O4 nanosheet films on fluorine-doped tin oxide substrates by a low-temperature solution process. Low-cost NiCo2S4 and NiCo2O4 nanosheet films were directly used for replacing conventional Pt and NiO as counter electrodes and photocathodes, respectively, to construct all-nano p-type dye-sensitized solar cells (p-DSSCs) with high performance. Compared to Pt, NiCo2S4 showed higher catalytic activity towards the I-/I3- redox in electrolyte, resulting in an improved photocurrent density up to 2.989mA/cm2, which is the highest value in reported p-DSSCs. Present p-DSSCs demonstrated a cell efficiency of 0.248% that is also comparable with typical NiO-based p-DSSCs. PMID:25489277

2014-01-01

317

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

318

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

SciTech Connect

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

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

2014-02-17

319

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

NASA Astrophysics Data System (ADS)

We report a highly efficient phosphorescent green inverted top emitting organic light emitting diode with excellent color stability by using the 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile/indium zinc oxide top electrode and bis(2-phenylpyridine)iridium(III) acetylacetonate as the emitter in an exciplex forming co-host system. The device shows a high external quantum efficiency of 23.4% at 1000 cd/m2 corresponding to a current efficiency of 110 cd/A, low efficiency roll-off with 21% at 10 000 cd/m2 and low turn on voltage of 2.4 V. Especially, the device showed very small color change with the variation of ?x = 0.02, ?y = 0.02 in the CIE 1931 coordinates as the viewing angle changes from 0 to 60. The performance of the device is superior to that of the metal/metal cavity structured device.

Kim, Jung-Bum; Lee, Jeong-Hwan; Moon, Chang-Ki; Kim, Jang-Joo

2014-02-01

320

Liquid-phase exfoliation of chemical vapor deposition-grown single layer graphene and its application in solution-processed transparent electrodes for flexible organic light-emitting devices  

NASA Astrophysics Data System (ADS)

Efficient and low-cost methods for obtaining high performance flexible transparent electrodes based on chemical vapor deposition (CVD)-grown graphene are highly desirable. In this work, the graphene grown on copper foil was exfoliated into micron-size sheets through controllable ultrasonication. We developed a clean technique by blending the exfoliated single layer graphene sheets with conducting polymer to form graphene-based composite solution, which can be spin-coated on flexible substrate, forming flexible transparent conducting film with high conductivity (8 ?/?), high transmittance (81% at 550 nm), and excellent mechanical robustness. In addition, CVD-grown-graphene-based polymer light emitting diodes with excellent bendable performances were demonstrated.

Wu, Chaoxing; Li, Fushan; Wu, Wei; Chen, Wei; Guo, Tailiang

2014-12-01

321

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

322

A solution-processed molybdenum oxide treated silver nanowire network: a highly conductive transparent conducting electrode with superior mechanical and hole injection properties.  

PubMed

We demonstrate the fabrication of solution-processed MoOx-treated (s-MoOx) silver nanowire (AgNW) transparent conductive electrodes (TCEs) utilizing low-temperature (sub-100 C) processes. The s-MoOx aggregates around the AgNW and forms gauze-like MoOx thin films between the mesh, which can effectively lower the sheet resistance by more than two orders of magnitude. Notably, these s-MoOx-treated AgNW TCEs exhibit a combination of several promising characteristics, such as a high and broad transmittance across a wavelength range of 400 to 1000 nm, transmission of up to 96.8%, a low sheet resistance of 29.8 ohm sq(-1), a low haze value of 0.90%, better mechanical properties against bending and adhesion tests, and preferable gap states for efficient hole injection in optoelectronic applications. By utilizing these s-MoOx-treated AgNW TCEs as the anode in ITO-free organic light emitting diodes, promising performance of 29.2 lm W(-1) and 10.3% external quantum efficiency are demonstrated. The versatile, multi-functional s-MoOx treatment presented here paves the way for the use of low-temperature, solution-processed MoOx as both a nanowire linker and a hole injection interfacial layer for future flexible optoelectronic devices. PMID:25687969

Chang, Jung-Hao; Chiang, Kai-Ming; Kang, Hao-Wei; Chi, Wei-Jung; Chang, Jung-Hung; Wu, Chih-I; Lin, Hao-Wu

2015-02-26

323

Transparent lithium-ion batteries , Sangmoo Jeongb  

E-print Network

Transparent lithium-ion batteries Yuan Yanga , Sangmoo Jeongb , Liangbing Hua , Hui Wua , Seok Woo, 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 transpar- ent and have to be thick

Cui, Yi

324

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

325

Transparent lithium-ion batteries.  

PubMed

Transparent devices have recently attracted substantial attention. Various applications have been demonstrated, including displays, touch screens, and solar cells; however, transparent batteries, a key component in fully integrated transparent devices, have not yet been reported. As battery electrode materials are not transparent and have to be thick enough to store energy, the traditional approach of using thin films for transparent devices is not suitable. Here we demonstrate a grid-structured electrode to solve this dilemma, which is fabricated by a microfluidics-assisted method. The feature dimension in the electrode is below the resolution limit of human eyes, and, thus, the electrode appears transparent. Moreover, by aligning multiple electrodes together, the amount of energy stored increases readily without sacrificing the transparency. This results in a battery with energy density of 10 Wh/L at a transparency of 60%. The device is also flexible, further broadening their potential applications. The transparent device configuration also allows in situ Raman study of fundamental electrochemical reactions in batteries. PMID:21788483

Yang, Yuan; Jeong, Sangmoo; Hu, Liangbing; Wu, Hui; Lee, Seok Woo; Cui, Yi

2011-08-01

326

Nutrition Counter  

MedlinePLUS

... Counter: A Reference For The Kidney Patient AAKP Nutrition Counter: A Reference For The Kidney Patient Buy ... Harum RD, CSR, LD Certified Specialist in Renal Nutrition, Miami, Florida Reviewed by: 2005 Maria Karalis, MBA, ...

327

Counting Counters  

NSDL National Science Digital Library

This problem gives children an opportunity to explore an increasing pattern and then generalize the results with a rule. Students begin with a single counter, surround it by a ring of other counters and then each new ring is surrounded with more counters. Solvers record results as they replicate the pattern and make predictions about many counters there will be in any given ring. The Teachers' Notes page offers suggestions for implementation, key discussion questions, ideas for extension and support.

328

Effect of deposition temperature on the properties of Al-doped ZnO films prepared by pulsed DC magnetron sputtering for transparent electrodes in thin-film solar cells  

NASA Astrophysics Data System (ADS)

A simple but scalable approach to the production of surface-textured Al-doped ZnO(AZO) films for low-cost transparent electrode applications in thin-film solar cells is introduced in this study by combining pulsed dc magnetron sputtering (PDMS) with wet etching in sequence. First, structural, electrical, and optical properties of the AZO films prepared by a PDMS were investigated as functions of deposition temperature to obtain transparent electrode films that can be used as indium-free alternative to ITO electrodes. Increase in the deposition temperature to 230 C accompanied the improvement in crystalline quality and doping efficiency, which enabled the lowest electrical resistivity of 4.16 10-4 ? cm with the carrier concentration of 1.65 1021 cm-3 and Hall mobility of 11.3 cm2/V s. The wet etching of the films in a diluted HCl solution resulted in surface roughening via the formation of crater-like structures without significant degradation in the electrical properties, which is responsible for the enhanced light scattering capability required for anti-reflective electrodes in thin film solar cells.

Kim, Doo-Soo; Park, Ji-Hyeon; Shin, Beom-Ki; Moon, Kyeong-Ju; Son, Myoungwoo; Ham, Moon-Ho; Lee, Woong; Myoung, Jae-Min

2012-10-01

329

Transparent Conducting Coatings  

Microsoft Academic Search

Optical and electrical transmission\\/absorption (resistance) properties of thin metal films and semiconductor coatings are reviewed, with attention given to thin transparent electrode coatings. Materials known to attain electrical conductivities of 1000\\/ohm\\/cm while retaining good optical transparency are covered in the review. Optical transmission and absorption, electrical conductivity and electrical sheet resistance, and figure of merit formulations are considered for thin

G. Haacke

1977-01-01

330

A solution-processed molybdenum oxide treated silver nanowire network: a highly conductive transparent conducting electrode with superior mechanical and hole injection properties  

NASA Astrophysics Data System (ADS)

We demonstrate the fabrication of solution-processed MoOx-treated (s-MoOx) silver nanowire (AgNW) transparent conductive electrodes (TCEs) utilizing low-temperature (sub-100 C) processes. The s-MoOx aggregates around the AgNW and forms gauze-like MoOx thin films between the mesh, which can effectively lower the sheet resistance by more than two orders of magnitude. Notably, these s-MoOx-treated AgNW TCEs exhibit a combination of several promising characteristics, such as a high and broad transmittance across a wavelength range of 400 to 1000 nm, transmission of up to 96.8%, a low sheet resistance of 29.8 ohm sq-1, a low haze value of 0.90%, better mechanical properties against bending and adhesion tests, and preferable gap states for efficient hole injection in optoelectronic applications. By utilizing these s-MoOx-treated AgNW TCEs as the anode in ITO-free organic light emitting diodes, promising performance of 29.2 lm W-1 and 10.3% external quantum efficiency are demonstrated. The versatile, multi-functional s-MoOx treatment presented here paves the way for the use of low-temperature, solution-processed MoOx as both a nanowire linker and a hole injection interfacial layer for future flexible optoelectronic devices.We demonstrate the fabrication of solution-processed MoOx-treated (s-MoOx) silver nanowire (AgNW) transparent conductive electrodes (TCEs) utilizing low-temperature (sub-100 C) processes. The s-MoOx aggregates around the AgNW and forms gauze-like MoOx thin films between the mesh, which can effectively lower the sheet resistance by more than two orders of magnitude. Notably, these s-MoOx-treated AgNW TCEs exhibit a combination of several promising characteristics, such as a high and broad transmittance across a wavelength range of 400 to 1000 nm, transmission of up to 96.8%, a low sheet resistance of 29.8 ohm sq-1, a low haze value of 0.90%, better mechanical properties against bending and adhesion tests, and preferable gap states for efficient hole injection in optoelectronic applications. By utilizing these s-MoOx-treated AgNW TCEs as the anode in ITO-free organic light emitting diodes, promising performance of 29.2 lm W-1 and 10.3% external quantum efficiency are demonstrated. The versatile, multi-functional s-MoOx treatment presented here paves the way for the use of low-temperature, solution-processed MoOx as both a nanowire linker and a hole injection interfacial layer for future flexible optoelectronic devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr06805j

Chang, Jung-Hao; Chiang, Kai-Ming; Kang, Hao-Wei; Chi, Wei-Jung; Chang, Jung-Hung; Wu, Chih-I.; Lin, Hao-Wu

2015-02-01

331

VOLTAMMETRIC MEMBRANE CHLORINE DIOXIDE ELECTRODE  

EPA Science Inventory

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

332

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 ??focuses on prevention and reforming systems?. With a well-designed and rather elegant homepage, visitors will find much to admire here. The top of the homepage provides access to their ??In Focus? feature, which draws attention to some of TI??s 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 ??Corruption: Learn About it? 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 ??How to Fight Corruption? section, which contains an anti-corruption handbook and a set of business principles for countering bribery.

333

Transparent and Catalytic Carbon Nanotube Films  

E-print Network

. Ozone-treated, defective nanotube films could serve as catalytic, transparent, and conducting electrodes is commonly made from a thin (1­5 nm) layer of platinum catalyst deposited on a transparent conducting oxide not degrade.15 In addition, multiple papers demonstrate the high conductivity and transparency of carbon

Hone, James

334

Room-temperature synthesis of Cu(2-x)E (E = S, Se) nanotubes with hierarchical architecture as high-performance counter electrodes of quantum-dot-sensitized solar cells.  

PubMed

Copper chalcogenide nanostructures (e.g. one-dimensional nanotubes) have been the focus of interest because of their unique properties and great potential in various applications. Their current fabrications mainly rely on high-temperature or complicated processes. Here, with the assistance of theoretical prediction, we prepared Cu(2-x)E (E = S, Se) micro-/nanotubes (NTs) with a hierarchical architecture by using copper nanowires (Cu NWs), stable sulfur and selenium powder as precursors at room temperature. The influence of reaction parameters (e.g. precursor ratio, ligands, ligand ratio, and reaction time) on the formation of nanotubes was comprehensively investigated. The resultant Cu(2-x)E (E = S, Se) NTs were used as counter electrodes (CE) of quantum-dot-sensitized solar cells (QDSSCs) to achieve a conversion efficiency (?) of 5.02 and 6.25%, respectively, much higher than that of QDSSCs made with Au CE (? = 2.94%). PMID:25400022

Chen, Xin Qi; Li, Zhen; Bai, Yang; Sun, Qiao; Wang, Lian Zhou; Dou, Shi Xue

2015-01-12

335

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

336

Electrolessly Deposited Electrospun Metal Nanowire Transparent Po-Chun Hsu,  

E-print Network

-scale manufacturing. Transparent conducting electrodes (TCEs) are indispen- sable components in many optoelectronicElectrolessly Deposited Electrospun Metal Nanowire Transparent Electrodes Po-Chun Hsu, Desheng Kong ABSTRACT: Metal nanowire (MNW) transparent elec- trodes have been widely developed for their promising

Cui, Yi

337

Brick-like N-doped graphene/carbon nanotube structure forming three-dimensional films as high performance metal-free counter electrodes in dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

The "brick-like" N-doped graphene-carbon nanotube (NGC) composites are designed by mechanically grinding the filtration films, which are fabricated to form a three-dimensional structure film as a counter electrode (CE). The N-doped graphene/carbon nanotube films with a three-dimensional "brick-like" structure can provide numerous vertical active edge sites. The excellent electrochemical catalytic activities of CE can be obtained by adjusting the different ratio of graphene to CNTs to control the size and N-doping content of breaking particles. NGC17 CE based dye-sensitized solar cells (DSSC) have reached a high efficiency (6.74%) close to platinum-based cells (6.89%). The excellent efficiency may be attributed to the following factors: a) the ?EP of NGC17 (304 mV) is lower than that of the Pt electrode (389 mV); b) the charge transfer resistance (Rct) at the NGC17-CE/electrolyte interface was 1.78 ? cm-2, which is lower than that of a Pt-CE/electrolyte interface (8.97 ? cm-2).

Ma, Jie; Li, Cheng; Yu, Fei; Chen, Junhong

2015-01-01

338

Improved External Efficiency InGaN-Based Light-Emitting Diodes with Transparent Conductive Ga-Doped ZnO as p-Electrodes  

Microsoft Academic Search

Transparent conductive Ga-doped ZnO (ZnO:Ga) was fabricated to serve as p-contacts of InGaN-based light-emitting diodes (LEDs) using molecular-beam epitaxy. As-grown ZnO:Ga films typically have resistivities of rho=2-4 10-4 Omega\\\\cdotcm, and over 80% transparency in the near UV and visible wavelength ranges. The current-voltage characteristics between as-grown ZnO:Ga contacts and p-GaN layers were ohmic. The brightness of LEDs fabricated with ZnO:Ga

Ken Nakahara; Kentaro Tamura; Mitsuhiko Sakai; Daisuke Nakagawa; Norikazu Ito; Masayuki Sonobe; Hidemi Takasu; Hitoshi Tampo; Paul Fons; Koji Matsubara; Kakuya Iwata; Akimasa Yamada; Shigeru Niki

2004-01-01

339

Measurement of the electro-optic properties of poled polymers at lambda=1.55 mum by means of sandwich structures with zinc oxide transparent electrode  

Microsoft Academic Search

We report on the measurement of the electro-optic properties of poled polymers at lambda=1.55 mum via the Teng and Man technique. Measurements of the electro-optic coefficient obtained for two different sandwich structures, using either indium tin oxide (ITO) or aluminum doped zinc oxide (ZnO:Al) semitransparent electrodes, are compared. The experimental results show that the use of ITO electrodes can lead

F. Michelotti; A. Belardini; M. C. Larciprete; M. Bertolotti; A. Rousseau; A. Ratsimihety; G. Schoer; J. Mueller

2003-01-01

340

A novel system of electrodes transparent to ultrasound for simultaneous detection of myoelectric activity and B-mode ultrasound images of skeletal muscles.  

PubMed

Application of two-dimensional surface electrode arrays can provide a means of mapping motor unit action potentials on the skin surface above a muscle. The resulting muscle tissue displacement can be quantified, in a single plane, using ultrasound (US) imaging. Currently, however, it is not possible to simultaneously map spatio-temporal propagation of activation and resulting tissue strain. In this paper, we developed and tested a material that will enable concurrent measurement of two-dimensional surface electromyograms (EMGs) with US images. Specific protocols were designed to test the compatibility of this new electrode material, both with EMG recording and with US analysis. Key results indicate that, for this new electrode material, 1) the electrode-skin impedance is similar to that of arrays of electrodes reported in literature; 2) the reflection of US at the electrode-skin interface is negligible; 3) the likelihood of observing missing contacts, short-circuits, and artifacts in EMGs is not affected by the US probe; 4) movement of tissues sampled by US can be tracked accurately. We, therefore, conclude this approach will facilitate multimodal imaging of muscle to provide new spatio-temporal information regarding electromechanical function of muscle. This is relevant to basic physiology-biomechanics of active and passive force transmission through and between muscles, of motor unit spatio-temporal activity patterns, of their variation with architecture and task-related function, and of their adaptation with aging, training-exercise-disuse, neurological disease, and injury. PMID:23908313

Botter, A; Vieira, T M M; Loram, I D; Merletti, R; Hodson-Tole, E F

2013-10-15

341

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

342

Effect of Gold Thickness and Annealing on Optical and Electrical Properties of TiO2/Au/TiO2 Multilayers as Transparent Composite Electrode on Flexible Substrate  

NASA Astrophysics Data System (ADS)

Multilayer structures of TiO2/Au/TiO2 have been deposited onto flexible substrates by room temperature sputtering to develop indium-free transparent composite electrodes (TCEs). The effect of Au thicknesses on optical, electrical properties and the mechanism of conduction have been discussed. The electrical conductivity of the TCEs is solely contributed by the middle metal layer. The critical thickness (t c) of the Au mid-layer to form a continuous conducting layer is 10 nm, and the multilayer has been optimized to obtain a sheet resistance of 12.2 ?/sq and an average optical transmittance of 86% at 590 nm. The Haacke figure of merit (FOM) for t c has one of the highest FOM with 18 10-3 ?-1. The samples were annealed in various environments for 24 h up to 150C.

Dhar, Aritra; Zhao, Zhao; Alford, T. L.

2015-03-01

343

Direct transparent electrode patterning on layered GaN substrate by screen printing of indium tin oxide nanoparticle ink for Eu-doped GaN red light-emitting diode  

NASA Astrophysics Data System (ADS)

Transparent electrodes were formed on Eu-doped GaN-based red-light-emitting diode (GaN:Eu LED) substrates by the screen printing of indium tin oxide nanoparticle (ITO np) inks as a wet process. The ITO nps with a mean diameter of 25 nm were synthesized by the controlled thermolysis of a mixture of indium complexes and tin complexes. After the direct screen printing of ITO np inks on GaN:Eu LED substrates and sintering at 850 C for 10 min under atmospheric conditions, the resistivity of the ITO film was 5.2 m? cm. The fabricated LED up to 3 mm square surface emitted red light when the on-voltage was exceeded.

Kashiwagi, Y.; Koizumi, A.; Takemura, Y.; Furuta, S.; Yamamoto, M.; Saitoh, M.; Takahashi, M.; Ohno, T.; Fujiwara, Y.; Murahashi, K.; Ohtsuka, K.; Nakamoto, M.

2014-12-01

344

Spray deposition of water-soluble multiwall carbon nanotube and Cu2ZnSnSe4 nanoparticle composites as highly efficient counter electrodes in a quantum dot-sensitized solar cell system  

NASA Astrophysics Data System (ADS)

In this paper, low-cost counter electrodes (CEs) based on water-soluble multiwall carbon nanotube (MWCNT) and Cu2ZnSnSe4 nanoparticle (CZTSe NP) composites have been successfully introduced into a quantum dot-sensitized solar cell (QDSC) system. Suitable surface modification allows the MWCNTs and CZTSe NPs to be homogeneously dispersed in water, facilitating the subsequent low-temperature spray deposition of high quality composite films with different composite ratios. The electrochemical catalytic activity of the composite CEs has been critically compared by electrochemical impedance spectroscopy and Tafel-polarization analysis. It is found that the composite CE at the MWCNT : CZTSe ratio of 0.1 offers the best performance, leading to an optimal solar cell efficiency of 4.60%, which is 50.8% higher than that of the Pt reference CE. The as-demonstrated higher catalytic activity of the composite CEs compared to their single components could be ascribed to the combination of the fast electron transport of the MWCNTs and the high catalytic activity of CZTSe NPs.In this paper, low-cost counter electrodes (CEs) based on water-soluble multiwall carbon nanotube (MWCNT) and Cu2ZnSnSe4 nanoparticle (CZTSe NP) composites have been successfully introduced into a quantum dot-sensitized solar cell (QDSC) system. Suitable surface modification allows the MWCNTs and CZTSe NPs to be homogeneously dispersed in water, facilitating the subsequent low-temperature spray deposition of high quality composite films with different composite ratios. The electrochemical catalytic activity of the composite CEs has been critically compared by electrochemical impedance spectroscopy and Tafel-polarization analysis. It is found that the composite CE at the MWCNT : CZTSe ratio of 0.1 offers the best performance, leading to an optimal solar cell efficiency of 4.60%, which is 50.8% higher than that of the Pt reference CE. The as-demonstrated higher catalytic activity of the composite CEs compared to their single components could be ascribed to the combination of the fast electron transport of the MWCNTs and the high catalytic activity of CZTSe NPs. Electronic supplementary information (ESI) available: Photographs, SEM, Raman, EDX and EDX-mapping results. See DOI: 10.1039/c3nr01564e

Zeng, Xianwei; Xiong, Dehua; Zhang, Wenjun; Ming, Liqun; Xu, Zhen; Huang, Zhanfeng; Wang, Mingkui; Chen, Wei; Cheng, Yi-Bing

2013-07-01

345

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

346

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

PubMed

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 (?). PMID:24121304

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

2013-12-01

347

Spray deposition of water-soluble multiwall carbon nanotube and Cu2ZnSnSe4 nanoparticle composites as highly efficient counter electrodes in a quantum dot-sensitized solar cell system.  

PubMed

In this paper, low-cost counter electrodes (CEs) based on water-soluble multiwall carbon nanotube (MWCNT) and Cu2ZnSnSe4 nanoparticle (CZTSe NP) composites have been successfully introduced into a quantum dot-sensitized solar cell (QDSC) system. Suitable surface modification allows the MWCNTs and CZTSe NPs to be homogeneously dispersed in water, facilitating the subsequent low-temperature spray deposition of high quality composite films with different composite ratios. The electrochemical catalytic activity of the composite CEs has been critically compared by electrochemical impedance spectroscopy and Tafel-polarization analysis. It is found that the composite CE at the MWCNT : CZTSe ratio of 0.1 offers the best performance, leading to an optimal solar cell efficiency of 4.60%, which is 50.8% higher than that of the Pt reference CE. The as-demonstrated higher catalytic activity of the composite CEs compared to their single components could be ascribed to the combination of the fast electron transport of the MWCNTs and the high catalytic activity of CZTSe NPs. PMID:23800939

Zeng, Xianwei; Xiong, Dehua; Zhang, Wenjun; Ming, Liqun; Xu, Zhen; Huang, Zhanfeng; Wang, Mingkui; Chen, Wei; Cheng, Yi-Bing

2013-08-01

348

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

349

A significant improvement in the electrocatalytic stability of N-doped graphene nanosheets used as a counter electrode for [Co(bpy)3](3+/2+) based porphyrin-sensitized solar cells.  

PubMed

A significant improvement in efficiency is achieved for porphyrin (YD2-o-C8) based dye-sensitized solar cells, coupled with [Co(bpy)3](3+/2+) mediator electrolyte. However, the poison of the counter electrode (CE) by the [Co(bpy)3](3+/2+) mediator remains a significant barrier to producing a reliable high-performance device. In this paper, nitrogen-doped graphene nanosheets (NG) are produced using a low-cost solution-based process and are used as the CE for [Co(bpy)3](3+/2+) based porphyrin-sensitized solar cells. These produce significantly better electrocatalytic activity than the commonly used Pt CE. The superior performance is a result of the increased number of catalytic sites and the wettable surface that is caused by the substitution of pyridinic and pyrrolic N into the carbon-conjugated lattice. To the authors' best knowledge, the significantly improved cycling stability (>1000 times) of NG CE for [Co(bpy)3](3+/2+) redox complexes is demonstrated for the first time. PMID:25556598

Zhai, Peng; Lee, Chih-Chi; Chang, Ya-Huei; Liu, Chang; Wei, Tzu-Chien; Feng, Shien-Ping

2015-01-28

350

Facile synthesis of poly(3,4-ethylenedioxythiophene) film via solid-state polymerization as high-performance Pt-free counter electrodes for plastic dye-sensitized solar cells.  

PubMed

A high-performance Pt-free counter electrode (CE) based on poly(3,4-ethylenedioxythiophene) (PEDOT) film for plastic dye-sensitized solar cells (DSCs) has been developed via a facile solid-state polymerization (SSP) approach. The polymerization was simply initiated by sintering the monomer, 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT), at the temperature of 80 C, which can be applied on the plastic substrate. The cyclic voltammetry measurements revealed that the catalytic activity of the SSP-PEDOT CE for triiodide reduction is comparable with that of the Pt CE. Under optimized conditions, the power conversion efficiency of a DSC with a N719-sensitized TiO2 photoanode and the SSP-PEDOT CE is 7.04% measured under standard 1 sun illumination (100 mW cm(-2), AM 1.5), which is very close to that of the device fabricated under the same conditions with a conventional thermally deposited Pt CE (7.35%). Furthermore, taking advantage of the compatibility of the SSP-PEDOT with the plastic substrates, a full plastic N719-sensitized TiO2 solar cell was demonstrated, and an efficiency of 4.65% was achieved, which is comparable with the performance of a plastic DSC with a sputter-deposited Pt CE (5.38%). These results demonstrated that solid-state polymerization initiated at low temperature is a facile and low-cost method of fabricating the high-performance Pt-free CEs for plastic DSCs. PMID:23927540

Yin, Xiong; Wu, Fan; Fu, Nianqing; Han, Jing; Chen, Dongliang; Xu, Peng; He, Meng; Lin, Yuan

2013-09-11

351

Infrared transparent carbon nanotube thin films  

NASA Astrophysics Data System (ADS)

We have measured the infrared properties of optically transparent and electrically conductive single walled carbon nanotube thin films. We found that nanotube films with sheet resistance values of 200 ?/sq show outstanding transmittance in the infrared range up to at least 22 ?m, with an average transmittance greater than 90% over this range. The infrared properties of various materials were compared and we found that transparent nanotube electrodes and transparent graphene electrodes outperform the others in several key categories. This study opens another important application area for conductive nanotube thin films.

Hu, Liangbing; Hecht, David S.; Grner, George

2009-02-01

352

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

353

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

354

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

E-print Network

Nano 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 as the most important transparent conductive electrode (TCE). This need mainly arises because of the rising

Zhou, Chongwu

355

Distributed performance counters  

DOEpatents

A plurality of first performance counter modules is coupled to a plurality of processing cores. The plurality of first performance counter modules is operable to collect performance data associated with the plurality of processing cores respectively. A plurality of second performance counter modules are coupled to a plurality of L2 cache units, and the plurality of second performance counter modules are operable to collect performance data associated with the plurality of L2 cache units respectively. A central performance counter module may be operable to coordinate counter data from the plurality of first performance counter modules and the plurality of second performance modules, the a central performance counter module, the plurality of first performance counter modules, and the plurality of second performance counter modules connected by a daisy chain connection.

Davis, Kristan D; Evans, Kahn C; Gara, Alan; Satterfield, David L

2013-11-26

356

Electrodynamic Arrays Having Nanomaterial Electrodes  

NASA Technical Reports Server (NTRS)

An electrodynamic array of conductive nanomaterial electrodes and a method of making such an electrodynamic array. In one embodiment, a liquid solution containing nanomaterials is deposited as an array of conductive electrodes on a substrate, including rigid or flexible substrates such as fabrics, and opaque or transparent substrates. The nanomaterial electrodes may also be grown in situ. The nanomaterials may include carbon nanomaterials, other organic or inorganic nanomaterials or mixtures.

Trigwell, Steven (Inventor); Biris, Alexandru S. (Inventor); Calle, Carlos I. (Inventor)

2013-01-01

357

Transparent and Conductive Carbon Nanotube Multilayer Thin Films Suitable as an Indium Tin Oxide Replacement  

E-print Network

Transparent electrodes made from metal oxides suffer from poor flexibility and durability. Highly transparent and electrically conductive thin films based on carbon nanotubes (CNTs) were assembled as a potential indium tin oxide (ITO) replacement...

Park, Yong Tae

2012-07-16

358

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

359

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.

360

Nanoimprint-assisted fabrication of high haze metal mesh electrode for solar cells  

NASA Astrophysics Data System (ADS)

We propose a concept of transparent electrode for solar cells surpassing conventional transparent conductive oxide. Transparent electrode requires low electrical resistivity, high optical transparency, and high optical haze. Although transparent conductive oxide by chemical vapor deposition is widely used as a transparent electrode for solar cells, a breakthrough of the trade-off between electrical and optical properties is required for further improvement of solar cell efficiency. We demonstrate solution-processed electrode fabrication by using nanoimprint technology and metal nanoparticle ink. Silver mesh electrode is self-aligned on nanoimprinted texture with concave pattern as a template for mesh grid. Our electrode concept can realize desired high optical haze by nanoimprinted texture, as well as low electrical resistivity and high optical transparency by metal mesh electrode simultaneously, which boosts solar cell efficiency.

Iwahashi, Takashi; Yang, Rong; Okabe, Noriaki; Sakurai, Junpei; Lin, Jun; Matsunaga, Daisuke

2014-12-01

361

Characterization of new transparent organic electrode materials  

Microsoft Academic Search

We characterize thin films of a new conductive copolymer, sulfonated poly(thiophene-3-[2-(2-methoxyethoxy)ethoxy]-2,5-diyl) (S-P3MEET), with various chemical additives to determine if the films are suitable for use as a hole transport layer in organic electronic devices. Using atomic force microscopy, Kelvin probe, and contact angle measurements, we probe the surface morphology and composition of S-P3MEET thin films. We then use DC conductivity

Scott A. Mauger; Adam J. Moul

2011-01-01

362

Fabrication of tantalum and nitrogen codoped ZnO (Ta, N-ZnO) thin films using the electrospay: twin applications as an excellent transparent electrode and a field emitter.  

PubMed

The realization of stable p-type nitrogen-doped ZnO thin films with durable and controlled growth is important for the fabrication of nanoscale electronic and optoelectronic devices. ZnO thin films codoped with tantalum and nitrogen (Ta, N-ZnO) were fabricated by using the electrospraying method at an atmospheric pressure. X-ray diffraction (XRD) studies demonstrated that all the prepared films were polycrystalline in nature with hexagonal wurtzite structure. In addition, a shift in the XRD patterns was observed, and the crystal orientation was changed at a certain amount of nitrogen (>6 at.%) in the starting solution. Analysis of X-ray diffraction patterns and X-ray photoelectron spectra revealed that nitrogen which was combined with the zinc atom (N-Zn) was successfully doped into the ZnO crystal lattice. It was also observed that 2 at.% tantalum and 6 at.% nitrogen (2 at.% Ta and 6 at.% N) were the optimal dopant amounts to achieve the minimum resistivity of about 9.70 10(-5) ? cm and the maximum transmittance of 98% in the visible region. Consequently, the field-emission characteristics of such a Ta, N-ZnO emitter can exhibit the higher current density of 1.33 mA cm(-2), larger field-enhancement factor (?) of 4706, lower turn-on field of 2.6 V ?m(-1), and lower threshold field of 3.5 V ?m(-1) attributed to the enhanced conductivity and better crystallinity of films. Moreover, the obtained values of resistivity were closest to the lowest resistivity values among the doped ZnO films as well as to the indium tin oxide (ITO) resistivity values that were previously studied. We confirmed that the tantalum and nitrogen atoms substitution in the ZnO lattice induced positive effects in terms of enhancing the free carrier concentration which will further improve the electrical, optical, and field-emission properties. The proposed electrospraying method was well suitable for the fabrication of Ta, N-ZnO thin films at optimum conditions with superior electrical, optical, and field-emission characteristics, implying the potential applications as both a transparent electrode and field-emission (FE) devices. PMID:23547983

Mahmood, Khalid; Park, Seung Bin; Sung, Hyung Jin

2013-05-01

363

Silver nanowires embedded gel electrodes  

NASA Astrophysics Data System (ADS)

The polyelectrolyte of high-strength gels was made to improve the mechanical properties in our previous study. In the field of electronic devices, the demand of polymer electrodes, which have high conductivity, high flexibility and transparence, is increasing. In this study, we attempt to make a transparent polymer electrode by laminating polymer thin film and silver nanowire (AgNW). High transparenct poly(methyl methacrylate) (PMMA) film, which is produced by using solvent cast method is used. AgNW is prepared by reacting Silver chloride (AgCl) with Silver nitrate (AgNO3) based on previous study. The AgNWs taking on different shapes were obtained. Fibrous AgNWs are formed by using high molecular weight polyvinylpyrrolidone (PVP). These results showed a possibility of developing the polymer electrode with high conductivity, high flexibility and transparence.

Abe, Yuta; Gong, Jin; Furukawa, Hidemitsu

2013-04-01

364

Transparent switchboard  

NASA Technical Reports Server (NTRS)

A tin oxide coating is formed on a plate of glass and the coating is then etched away from the glass in thin lines to form separate electrical conductors which extend to one end of the plate and connect to either a vertical (column) or horizontal (row) position sensing SCR circuit. A thin transparent insulating coating is formed over the oxide layer except at selected touch points which are positioned in a matrix pattern of vertical columns and horizontal rows. Touching one of these points with a finger bridges the thin line between adjacent conductors to activate trigger circuits in the particular row and column sensing circuits associated with the point touched. The row and column sensing circuits are similar and are powered with a low frequency, ac voltage source. The source for the row circuits is 180 out of phase with the source for the column circuits so that one circuit acts as ground for the other during half of the supply voltage cycle. The signals from the sensing circuits are input to a logic circuit which determines the presence of a valid touch, stores a binary matrix number associated with the touched point, signals a computer of the presence of a stored number and prevents storage of a new number before receiving an enable signal from the computer.

Rasmussen, H. P. (inventor)

1973-01-01

365

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

366

Visibly transparent polymer solar cells produced by solution processing.  

PubMed

Visibly transparent photovoltaic devices can open photovoltaic applications in many areas, such as building-integrated photovoltaics or integrated photovoltaic chargers for portable electronics. We demonstrate high-performance, visibly transparent polymer solar cells fabricated via solution processing. The photoactive layer of these visibly transparent polymer solar cells harvests solar energy from the near-infrared region while being less sensitive to visible photons. The top transparent electrode employs a highly transparent silver nanowire-metal oxide composite conducting film, which is coated through mild solution processes. With this combination, we have achieved 4% power-conversion efficiency for solution-processed and visibly transparent polymer solar cells. The optimized devices have a maximum transparency of 66% at 550 nm. PMID:22789123

Chen, Chun-Chao; Dou, Letian; Zhu, Rui; Chung, Choong-Heui; Song, Tze-Bin; Zheng, Yue Bing; Hawks, Steve; Li, Gang; Weiss, Paul S; Yang, Yang

2012-08-28

367

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

368

A transparent ?ECoG array for simultaneous recording and optogenetic stimulation  

Microsoft Academic Search

In this paper we report for the first time the design, fabrication and characterization of an optically transparent electrode array for micro-electrocorticography. We present a 49-channel ?ECoG array with an electrode pitch of 800 ?m and a 16-channel linear ?ECoG array with an electrode pitch of 200 ?m. The backing material was Parylene C. Transparent, sputtered indium tin oxide (ITO)

Peter Ledochowitsch; Elisa Olivero; Tim Blanche; Michel M. Maharbiz

2011-01-01

369

Length dependence of the electronic transparence (conductance) of a molecular wire  

Microsoft Academic Search

The electronic transparence of a single molecular wire connecting the two electrodes of a metal-insulating-metal nanojunction decreases exponentially with its length. The transparence attenuation can be quite small depending of the homo-lumo gap of the molecule and of electronic interaction of the wire ends with the electrodes. For a 10 nm long polyene connecting two nano-electrodes, a 100 mV bias

C. Joachim; J. F. Vinuesa

1996-01-01

370

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

371

Transparent polymer cathode for organic photovoltaic devices  

Microsoft Academic Search

We demonstrate a prototype solar cell with a transparent polymer cathode, and indium-tin-oxide (ITO)\\/poly (3, 4-ethylene dioxythiophene)-poly (styrene sulphonate) (PEDOT:PSS) anode. As an active layer, thin film of a bulk heterojunction of polyfluorene copolymer poly[2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4?,7?-di-2thienyl-2?,1?3?-benzothiadiazole)] (APFO-3) and an electron acceptor molecule [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) (1:4wt.) was sandwiched between the two transparent polymer electrodes. The cathode is another form

Abay Gadisa; Kristofer Tvingstedt; Shimelis Admassie; L. Lindell; X. Crispin; Mats R. Andersson; W. R. Salaneck; Olle Ingans

2006-01-01

372

cis-dichloro-bis(4,4'-dicarboxy-2,2-bipyridine)osmium(II)-modified optically transparent electrodes: application as cathodes in stacked dye-sensitized solar cells.  

PubMed

An optically transparent cathode was developed for use in dye-sensitized solar cells. Fluorine-doped tin oxide conducting glass modified with a monolayer of cis-dichloro-bis(4,4'-dicarboxy-2,2'-bipyridine)osmium(II) efficiently reduces the oxidized form of the redox mediator. This transparent cathode transmits light that is not absorbed by the dyed TiO2; consequently, more than one cell can operate in optical tandem (i.e., stacked). Two types of stacked cells are considered: one where both photoanodes are dyed with the same dye and one where the photoanodes are dyed with different, spectrally complementary dyes. Overall behavior of these tandem cells is compared with single-cell analogs. PMID:17975889

Scott, Michael J; Nelson, Jeremy J; Caramori, Stefano; Bignozzi, Carlo A; Elliott, C Michael

2007-11-26

373

Soils. Transparency Masters.  

ERIC Educational Resources Information Center

This document is a collection of 43 overhead transparency masters to be used as teaching aids in a course of study involving soils such as geology, agronomy, hydrology, earth science, or land use study. Some transparencies are in color. Selected titles of transparencies may give the reader a better understanding of the graphic content. Titles are:

Clemson Univ., SC. Vocational Education Media Center.

374

Transparent self-cleaning dust shield  

DOEpatents

A transparent electromagnetic shield to protect solar panels and the like from dust deposition. The shield is a panel of clear non-conducting (dielectric) material with embedded parallel electrodes. The panel is coated with a semiconducting film. Desirably the electrodes are transparent. The electrodes are connected to a single-phase AC signal or to a multi-phase AC signal that produces a travelling electromagnetic wave. The electromagnetic field produced by the electrodes lifts dust particles away from the shield and repels charged particles. Deposited dust particles are removed when the electrodes are activated, regardless of the resistivity of the dust. Electrostatic charges on the panel are discharged by the semiconducting film. When used in conjunction with photovoltaic cells, the power for the device may be obtained from the cells themselves. For other surfaces, such as windshields, optical windows and the like, the power must be derived from an external source. One embodiment of the invention employs monitoring and detection devices to determine when the level of obscuration of the screen by dust has reached a threshold level requiring activation of the dust removal feature.

Mazumder, Malay K.; Sims, Robert A.; Wilson, James D.

2005-06-28

375

Transparent storage layers for H+ and Li+ ions prepared by sol-gel technique  

NASA Astrophysics Data System (ADS)

Thin layers of mixed oxides CeO2 - TiO2 and CeO2 - ZrO2 with molar ratio 1:1 have been prepared by sol-gel process using the dip-coating technique. The precursor sols consist of a mixture of nitrate ammonium cerium salt [Ce(NH4)2 (NO3)6], zirconium propoxide or tetraisopropyl orthotitanate, and ethanol. The thickness of the multilayer films is typically 300 nm after densification at 450 degree(s)C. Their use as transparent H+ and Li+ ions storage electrode (counter electrode) for electrochromic devices is studied by electrochemical voltammetry, impedance, and optical spectroscopies. They typically have an optical transmission of 80% in the visible range, do not color after ions insertion, and show good electrochemical stability. These layers also have been tested in complete, all solid state cell having the configuration glass/ITO/EC/electrolyte/CeO2 - TiO2/ITO/glass. The electrochromic layer (EC) was either WO3 or polytoluidine. The protonic electrolyte was a cellulose-polyacetate polymer and the lithium electrolyte was PEO-LiN(SO2CF3)2. Their electrochemical, optical, and lifetime performances are reported.

Valla, Bruno; Tonazzi, Juan C. L.; Macedo, Marcelo A.; Dall'Antonia, L. H.; Aegerter, Michel A.; Gomes, M. A.; Bulhoes, Luis O.

1991-12-01

376

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

377

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

378

Towards colorless transparent organic transistors: potential of benzothieno[3,2-b]benzothiophene-based wide-gap semiconductors.  

PubMed

Colorless, highly transparent organic thin-film transistors (TOTFTs) with high performance are realized based on benzothieno[3,2-b]benzothiophene (BTBT) derivatives that simultaneously exhibit a wide energy gap and high transport properties. Multilayer transparent source/drain electrodes maintain the transparency, and ultrathin fluoropolymer dielectric layers enable stable, low-voltage operation of the proposed TOTFTs. PMID:24496927

Moon, Hanul; Cho, Hyunsu; Kim, Mincheol; Takimiya, Kazuo; Yoo, Seunghyup

2014-05-21

379

Fully transparent and rollable electronics.  

PubMed

Major obstacles toward the manufacture of transparent and flexible display screens include the difficulty of finding transparent and flexible semiconductors and electrodes, temperature restrictions of flexible plastic substrates, and bulging or warping of the flexible electronics during processing. Here we report the fabrication and performance of fully transparent and rollable thin-film transistor (TFT) circuits for display applications. The TFTs employ an amorphous indium-gallium-zinc oxide semiconductor (with optical band gap of 3.1 eV) and amorphous indium-zinc oxide transparent conductive electrodes, and are built on 15-?m-thick solution-processed colorless polyimide (CPI), resulting in optical transmittance >70% in the visible range. As the CPI supports processing temperatures >300 C, TFT performance on plastic is similar to that on glass, with typical field-effect mobility, turn-on voltage, and subthreshold voltage swing of 12.7 0.5 cm(2)/Vs, -1.7 0.2 V, and 160 29 mV/dec, respectively. There is no significant degradation after rolling the TFTs 100 times on a cylinder with a radius of 4 mm or when shift registers, each consisting of 40 TFTs, are operated while bent to a radius of 2 mm. For handling purposes, carrier glass is used during fabrication, together with a very thin (?1 nm) solution-processed carbon nanotube (CNT)/graphene oxide (GO) backbone that is first spin-coated on the glass to decrease adhesion of the CPI to the glass; peel strength of the CPI from glass decreases from 0.43 to 0.10 N/cm, which eases the process of detachment performed after device fabrication. Given that the CNT/GO remains embedded under the CPI after detachment, it minimizes wrinkling and decreases the substrate's tensile elongation from 8.0% to 4.6%. Device performance is also stable under electrostatic discharge exposures up to 10 kV, as electrostatic charge can be released via the conducting CNTs. PMID:25526282

Mativenga, Mallory; Geng, Di; Kim, Byungsoon; Jang, Jin

2015-01-28

380

Compressor surge counter  

DOEpatents

A surge counter for a rotating compressor is provided which detects surging by monitoring the vibration signal from an accelerometer mounted on the shaft bearing of the compressor. The circuit detects a rapid increase in the amplitude envelope of the vibration signal, e.g., 4 dB or greater in less than one second, which is associated with a surge onset and increments a counter. The circuit is rendered non-responsive for a period of about 5 seconds following the detection which corresponds to the duration of the surge condition. This prevents multiple registration of counts during the surge period due to rapid swings in vibration amplitude during the period.

Castleberry, Kimberly N. (Harriman, TN)

1983-01-01

381

Present status of transparent conducting oxide thin-film development for Indium-Tin-Oxide (ITO) substitutes  

Microsoft Academic Search

This paper describes the present status and prospects for further development of transparent conducting oxide materials for use as Indium-Tin-Oxide (ITO) substitutes in the thin-film transparent electrodes of liquid crystal displays (LCDs), currently the largest use of ITO, and, thus, of indium. The best substitute material for the ITO transparent electrodes used in LCDs is impurity-doped ZnO, e.g., Al- and

Tadatsugu Minami

2008-01-01

382

Patternable transparent carbon nanotube films for electrochromic devices Liangbing Hu and George Grunera  

E-print Network

Patternable transparent carbon nanotube films for electrochromic devices Liangbing Hu and George nanotube films on polyethylene terephthalate as flexible electrodes in electrochromic devices using. Electrochromic devices attract much interest due to their potential use in applications such as smart windows

Gruner, George

383

Magnetron cathodes in plasma electrode pockels cells  

DOEpatents

Magnetron cathodes, which produce high current discharges, form greatly improved plasma electrodes on each side of an electro-optic crystal. The plasma electrode has a low pressure gas region on both sides of the crystal. When the gas is ionized, e.g., by a glow discharge in the low pressure gas, the plasma formed is a good conductor. The gas electrode acts as a highly uniform conducting electrode. Since the plasma is transparent to a high energy laser beam passing through the crystal, the plasma is transparent. A crystal exposed from two sides to such a plasma can be charged up uniformly to any desired voltage. A typical configuration utilizes helium at 50 millitorr operating. pressure and 2 kA discharge current. The magnetron cathode produces a more uniform plasma and allows a reduced operating pressure which leads to lower plasma resistivity and a more uniform charge on the crystal.

Rhodes, Mark A. (Pleasanton, CA)

1995-01-01

384

Magnetron cathodes in plasma electrode Pockels cells  

DOEpatents

Magnetron cathodes, which produce high current discharges, form greatly improved plasma electrodes on each side of an electro-optic crystal. The plasma electrode has a low pressure gas region on both sides of the crystal. When the gas is ionized, e.g., by a glow discharge in the low pressure gas, the plasma formed is a good conductor. The gas electrode acts as a highly uniform conducting electrode. Since the plasma is transparent to a high energy laser beam passing through the crystal, the plasma is transparent. A crystal exposed from two sides to such a plasma can be charged up uniformly to any desired voltage. A typical configuration utilizes helium at 50 millitorr operating pressure and 2 kA discharge current. The magnetron cathode produces a more uniform plasma and allows a reduced operating pressure which leads to lower plasma resistivity and a more uniform charge on the crystal. 5 figs.

Rhodes, M.A.

1995-04-25

385

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

386

Pionic Color Transparency  

E-print Network

We use a semi-classical approximation to investigate the effects of color transparency on pion electroproduction reactions. The resulting reduced nuclear interactions produce significant, but not dominating, differences with the results of conventional distorted-wave, Glauber-type treatments at kinematics accessible to Jefferson Laboratory. Nuclear effects that could mimic the influence of color transparency are also discussed.

Arnold Larson; Gerald A. Miller; M. Strikman

2006-04-11

387

Transparency in netchains  

Microsoft Academic Search

The paper defines transparency in agri chains and networks and discusses its preconditions, effects and institutional embedding. International aspects receive special attention. Because the food and agribusiness sector have such obvious links to public health, improving transparency in them is particularly important. The international context is imperative because most of the food we buy in our shops crosses national borders

Gert Jan Hofstede

2002-01-01

388

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

389

Countering the New Terrorism  

NSDL National Science Digital Library

_Countering the New Terrorism_, a new 153-page book published by RAND, has recently been made available online. The book contains four chapters that address the changes, trends, and implications of the new terrorism. The introductory chapter, written by Ian O. Lesser, overviews the changes in terrorism in a changing world. The second chapter, "Terrorism Trends and Prospects," by Bruce Hoffman, looks at trends in international terrorism. Chapter three, "Networks, Netwar, and Information-Age Terrorism," by John Arquilla, David Ronfeldt, and Michele Zanini, examines the special problem of terrorism in the information age. The final chapter, "Countering the New Terrorism: Implications for Strategy," also by Lesser, suggests how to meet terrorist challenges to US interests. The book also includes three figures, one table, an index, and a foreword by Brian Michael Jenkins. Each part of the online book is provided as an individual .pdf file.

Arquilla, John.

390

Bean Counter Accounting Tutorial  

NSDL National Science Digital Library

Frustrated with the lack of free accounting information available on the internet, Dave Marshall, small business owner of Bean Counter accounting services, created a tutorial of his own. Designed for the lay person, the tutorial steps the user through the basics of accounting. The tutorial is split into seven lessons, starting with basic definitions and terminology and then introduces the user to topics such as double entry bookkeeping and property rights.

Marshall, Dave

391

Simple Coulter Counter  

NSDL National Science Digital Library

Students build and use a very basic Coulter electric sensing zone particle counter to count an unknown number of particles in a sample of "paint" to determine if enough particles per ml of "paint" exist to meet a quality standard. In a lab experiment, student teams each build an apparatus and circuit, set up data acquisition equipment, make a salt-soap solution, test liquid flow in the apparatus, take data, and make graphs to count particles.

NSF CAREER Award and RET Program,

392

Transparent conducting silver nanowire networks  

E-print Network

We present a transparent conducting electrode composed of a periodic two-dimensional network of silver nanowires. Networks of Ag nanowires are made with wire diameters of 45-110 nm and pitch of 500, 700 and 1000 nm. Anomalous optical transmission is observed, with an averaged transmission up to 91% for the best transmitting network and sheet resistances as low as 6.5 {\\Omega}/sq for the best conducting network. Our most dilute networks show lower sheet resistance and higher optical transmittance than an 80 nm thick layer of ITO sputtered on glass. By comparing measurements and simulations we identify four distinct physical phenomena that govern the transmission of light through the networks: all related to the excitation of localized surface plasmons and surface plasmon polaritons on the wires. The insights given in this paper provide the key guidelines for designing high-transmittance and low-resistance nanowire electrodes for optoelectronic devices, including thin-film solar cells. For these latter, we disc...

van de Groep, Jorik; Polman, Albert; 10.1021/nl301045a

2013-01-01

393

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

394

DOI: 10.1002/adma.200501740 Highly Bendable, Transparent Thin-Film Transistors That Use  

E-print Network

,16] of individual SWNTs represent alternative classes of transparent semicon- ducting and conducting materialsDOI: 10.1002/adma.200501740 Highly Bendable, Transparent Thin-Film Transistors That Use Carbon of tubes per unit area) for all of the conduct- ing (i.e., source, drain, and gate electrodes

Rogers, John A.

395

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

396

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

397

Silver Nanowires (AgNWs) Embedded Electrodes for Gel Actuator  

NASA Astrophysics Data System (ADS)

In the field of electronic devices, the demand of polymer electrodes, which have high conductivity, high flexibility and transparence, is increasing. The polyelectrolyte of high-strength gels was made to improve the mechanical properties in our previous study [1]. In this study, we attempt to make a transparent polymer electrode by laminating polymer thin film and silver nanowires (AgNWs). High transparence poly(methyl methacrylate) (PMMA) film, which is produced by using solvent cast method. AgNWs are prepared by reacting Silver chloride (AgCl) with Silver nitrate (AgNO3) based on previous study[2]. The AgNWs taking on different shapes are obtained. Particle and fibrous AgNWs are formed by using low and high molecular weight polyvinylpyrrolidone (PVP), respectively (Fig. 1). The possibility of developing the polymer electrode with high conductivity, high flexibility and transparence is shown from these results.

Abe, Yuta; Gong, Jin; Hasnat Kabir, M.; Makino, Masato; Furukawa, Hidemitsu

398

Liquid electrode  

DOEpatents

A dropping electrolyte electrode is described for use in electrochemical analysis of non-polar sample solutions, such as benzene or cyclohexane. The liquid electrode, preferably an aqueous salt solution immiscible in the sample solution, is introduced into the solution in dropwise fashion from a capillary. The electrolyte is introduced at a known rate, thus, the droplets each have the same volume and surface area. The electrode is used in making standard electrochemical measurements in order to determine properties of non-polar sample solutions. 2 figures.

Ekechukwu, A.A.

1994-07-05

399

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

400

Stretchable, transparent, ionic conductors.  

PubMed

Existing stretchable, transparent conductors are mostly electronic conductors. They limit the performance of interconnects, sensors, and actuators as components of stretchable electronics and soft machines. We describe a class of devices enabled by ionic conductors that are highly stretchable, fully transparent to light of all colors, and capable of operation at frequencies beyond 10 kilohertz and voltages above 10 kilovolts. We demonstrate a transparent actuator that can generate large strains and a transparent loudspeaker that produces sound over the entire audible range. The electromechanical transduction is achieved without electrochemical reaction. The ionic conductors have higher resistivity than many electronic conductors; however, when large stretchability and high transmittance are required, the ionic conductors have lower sheet resistance than all existing electronic conductors. PMID:23990555

Keplinger, Christoph; Sun, Jeong-Yun; Foo, Choon Chiang; Rothemund, Philipp; Whitesides, George M; Suo, Zhigang

2013-08-30

401

Supersymmetric transparent optical intersections.  

PubMed

Supersymmetric (SUSY) optical structures provide a versatile platform to manipulate the scattering and localization properties of light, with potential applications to mode conversion, spatial multiplexing, and invisible devices. Here we show that SUSY can be exploited to realize broadband transparent intersections between guiding structures in optical networks for both continuous and discretized light. These include transparent crossing of high-contrast-index waveguides and directional couplers, as well as crossing of guiding channels in coupled resonator lattices. PMID:25680125

Longhi, Stefano

2015-02-15

402

Prospects of graphene electrodes in photovoltaics  

NASA Astrophysics Data System (ADS)

Transparent conductors (TCs) are becoming extremely popular in many different electronic applications such as touch panels, displays, light emitting devices, light sensors and solar cells. The commonly used electrode in these applications is Indium Tin Oxide (ITO). However, the cost of ITO is increasing rapidly due to the limited supply of Indium. Other issues such as lack of flexibility and cost of the deposition process make ITO less favorable in transparent electrode applications. Graphene has been under exploration as an alternative material for TC applications in the recent years. Graphene based TCs have been shown experimentally to exhibit promising electrical and optical properties. In this paper, the prospects of graphene for transparent conductors in photovoltaics are discussed. The recent advancements in this field as well as the theoretical predictions and possible pathways for improvements are presented. In the process section, we discuss methods to synthesize few-layer graphene (FLG) with high quality in a controllable manner.

Khatami, Yasin; Liu, Wei; Kang, Jiahao; Banerjee, Kaustav

2013-09-01

403

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

404

Quantum versus Deterministic Counter Automata  

Microsoft Academic Search

This paper focuses on quantum analogues of various models of counter automata, and almost completely proves the relation between\\u000a the classes of languages recognizable by bounded error quantum ones and classical deterministic ones in every model of counter\\u000a automata. It is proved that (i) under some practically reasonable assumption, quantum ones are strictly stronger than deterministic\\u000a ones in two-way one-counter

Tomohiro Yamasaki; Hirotada Kobayashi; Hiroshi Imai

2002-01-01

405

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

406

Subdural Electrodes  

PubMed Central

Subdural electrodes are frequently used to aid in the neurophysiological assessment of patients with intractable seizures. We review the indications for these, their uses for localizing epileptogenic regions and for localizing cortical regions supporting movement, sensation, and language. PMID:20573543

Lesser, Ronald P.; Crone, Nathan E.; Webber, W.R.S.

2010-01-01

407

Low latency counter event indication  

DOEpatents

A hybrid counter array device for counting events with interrupt indication includes a first counter portion comprising N counter devices, each for counting signals representing event occurrences and providing a first count value representing lower order bits. An overflow bit device associated with each respective counter device is additionally set in response to an overflow condition. The hybrid counter array includes a second counter portion comprising a memory array device having N addressable memory locations in correspondence with the N counter devices, each addressable memory location for storing a second count value representing higher order bits. An operatively coupled control device monitors each associated overflow bit device and initiates incrementing a second count value stored at a corresponding memory location in response to a respective overflow bit being set. The incremented second count value is compared to an interrupt threshold value stored in a threshold register, and, when the second counter value is equal to the interrupt threshold value, a corresponding "interrupt arm" bit is set to enable a fast interrupt indication. On a subsequent roll-over of the lower bits of that counter, the interrupt will be fired.

Gara, Alan G. (Mount Kisco, NY); Salapura, Valentina (Chappaqua, NY)

2008-09-16

408

Low latency counter event indication  

DOEpatents

A hybrid counter array device for counting events with interrupt indication includes a first counter portion comprising N counter devices, each for counting signals representing event occurrences and providing a first count value representing lower order bits. An overflow bit device associated with each respective counter device is additionally set in response to an overflow condition. The hybrid counter array includes a second counter portion comprising a memory array device having N addressable memory locations in correspondence with the N counter devices, each addressable memory location for storing a second count value representing higher order bits. An operatively coupled control device monitors each associated overflow bit device and initiates incrementing a second count value stored at a corresponding memory location in response to a respective overflow bit being set. The incremented second count value is compared to an interrupt threshold value stored in a threshold register, and, when the second counter value is equal to the interrupt threshold value, a corresponding "interrupt arm" bit is set to enable a fast interrupt indication. On a subsequent roll-over of the lower bits of that counter, the interrupt will be fired.

Gara, Alan G. (Mount Kisco, NY); Salapura, Valentina (Chappaqua, NY)

2010-08-24

409

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

410

Fabrication and Characterization of Porous DSC Counter Electrodes  

E-print Network

plots of symmetric cells with Pt CEs on FTO and NTO substrates with different RF. NTO substrates.3. PMMA, RF=13.3. PMMA, RF=17.2. PMMA, RF=17.2. TiO2 , RF=39. TiO2 , RF=39. Figure 4. Photoelectric (I illumination; dash: dark current. The photoelectric characteristics of DSCs based on FTO and NTO substrates

Candea, George

411

VLSI binary updown counter  

NASA Technical Reports Server (NTRS)

A pipeline binary updown counter is comprised of simple stages that may be readily replicated. Each stage is defined by the Boolean logic equation: A(sub n)(t) = A(sub n)(t - 1) exclusive OR (U AND P(sub n)) inclusive OR (D AND Q(sub n)), where A(sub n)(t) denotes the value of the nth bit at time t. The input to the counter has three values represented by two binary signals U and D such that if both are zero, the input is zero, if U = 0 and D = 1, the input is -1 and if U = 1 and D = 0, the input is +1. P(sub n) represents a product of A(sub k)'s for 1 is less than or equal to k is less than or equal to -1, while Q(sub n) represents the product of bar A's for 1 is less than or equal to K is less than or equal to n - 1, where bar A(sub k) is the complement of A(sub k) and P(sub n) and Q(sub n) are expressed as the following two equations: P(sub n) = A(sub n - 1) A(sub n - 2)...A(sub 1) and Q(sub n) = bar A(sub n - 1) bar A(sub n - 2)...bar A(sub 1), which can be written in recursive form as P(sub n) = P(sub n - 1) AND bar A(sub n - 1) and Q(sub n) = Q(sub n - 1) AND bar A(sub n - 1) with the initial values P(sub 1) = 1 and Q(sub 1) = 1.

Truong, Trieu-Kie (inventor); Hsu, In-Shek (inventor); Reed, Irving S. (inventor)

1989-01-01

412

Acne treatments (over-the-counter) Acupuncture  

E-print Network

-the-counter) Antibiotic ointment (over-the-counter) Aspirin or other pain reliever (over-the- counter) Asthma medicines-the- counter) Corneal keratotomy Cough drops & sore throat lozenges (over-the-counter) Cough syrup (over treatment Drugs (prescription) Dyslexia treatment Eye examinations Eye-related equipment/materials Eye

Bordenstein, Seth

413

Transparency and selfhood: Utopia and the informed body.  

PubMed

One aspect of the development of a health-orientated consumer culture is the growth of self-screening and self-diagnosis among the lay public--e.g. over-the-counter diagnostic tests, computerized health assessments. DIY genetic tests. This trend is interpreted as the expression of a distinctively postmodern 'utopian' impulse. Postmodernity's inwardly directed gaze has replaced the communitarian vision of modernity. In the absence of overarching visions, the postmodern utopian telos becomes the attainment of a perfect. imperishable body. Somatopia is the collective expression of these privatized and personalized body projects. The accomplishment and authentication of these body projects necessitates the creation of a 'transparent body'. This 'transparent body' is enabled and constructed by developments in information and medical technologies. The political and health implications of the transparent, 'informed' body are explored. PMID:11824922

Chrysanthou, Marc

2002-02-01

414

RECENT ADVANCES IN SCINTILLATION COUNTERS  

Microsoft Academic Search

Scintillation counters have allowed since the beginning a great variety ; of measurements due to the flexibility of their use. Numerous improvements have ; been made and they have presently a prominent place among radiation detectors. ; It is shown how, by technical improvements, in both laboratory and industry, the ; scintillation counter has become an instrument currently used in

Koechlin

1959-01-01

415

Over-the-Counter Medicines  

MedlinePLUS

Over-the-counter (OTC) medicines are drugs you can buy without a prescription. Some OTC medicines relieve aches, pains and itches. Some prevent or cure ... the Food and Drug Administration decides whether a medicine is safe enough to sell over-the-counter. ...

416

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

417

Permanently calibrated interpolating time counter  

NASA Astrophysics Data System (ADS)

We propose a new architecture of an integrated time interval counter that provides its permanent calibration in the background. Time interval measurement and the calibration procedure are based on the use of a two-stage interpolation method and parallel processing of measurement and calibration data. The parallel processing is achieved by a doubling of two-stage interpolators in measurement channels of the counter, and by an appropriate extension of control logic. Such modification allows the updating of transfer characteristics of interpolators without the need to break a theoretically infinite measurement session. We describe the principle of permanent calibration, its implementation and influence on the quality of the counter. The precision of the presented counter is kept at a constant level (below 20?ps) despite significant changes in the ambient temperature (from ?10 to 60?C), which can cause a sevenfold decrease in the precision of the counter with a traditional calibration procedure.

Jachna, Z.; Szplet, R.; Kwiatkowski, P.; R?yc, K.

2015-01-01

418

Cermet electrode  

DOEpatents

Disclosed is a cermet electrode consisting of metal particles of nickel, cobalt, iron, or alloys or mixtures thereof immobilized by zirconia stabilized in cubic form which contains discrete deposits of about 0.1 to about 5% by weight of praseodymium, dysprosium, terbium, or a mixture thereof. The solid oxide electrode can be made by covering a substrate with particles of nickel, cobalt, iron, or mixtures thereof, growing a stabilized zirconia solid oxide skeleton around the particles thereby immobilizing them, contacting the skeleton with a compound of praseodymium, dysprosium, terbium, or a mixture thereof, and heating the skeleton to a temperature of at least 500.degree. C. The electrode can also be made by preparing a slurry of nickel, cobalt, iron, or mixture and a compound of praseodymium, dysprosium, terbium, or a mixture thereof, depositing the slurry on a substrate, heating the slurry to dryness, and growing a stabilized zirconia skeleton around the metal particles.

Maskalick, Nicholas J. (Pittsburgh, PA)

1988-08-30

419

Photoelectrochemical electrodes  

NASA Technical Reports Server (NTRS)

The surface of a moderate band gap semiconductor such as p-type molybdenum sulfide is modified to contain an adherent film of charge mediating ionene polymer containing an electroactive unit such as bipyridimium. Electron transport between the electrode and the mediator film is favorable and photocorrosion and recombination processes are suppressed. Incorporation of particles of catalyst such as platinum within the film provides a reduction in overvoltage. The polymer film is readily deposited on the electrode surface and can be rendered stable by ionic or addition crosslinking. Catalyst can be predispersed in the polymer film or a salt can be impregnated into the film and reduced therein.

Williams, R. M.; Rembaum, A. (inventors)

1983-01-01

420

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

421

Plasmonic electrodes for bulk-heterojunction organic photovoltaics: a review  

NASA Astrophysics Data System (ADS)

Here, we review recent progress on the integration of plasmonic electrodes into bulk-heterojunction organic photovoltaic devices. Plasmonic electrodes, consisting of thin films of metallic nanostructures, can exhibit a number of optical, electrical, and morphological effects that can be exploited to improve performance parameters of ultrathin photovoltaic active layers. We review the various types of plasmonic electrodes that have been incorporated into organic photovoltaics such as nanohole, nanowire, and nanoparticle arrays and grating electrodes and their impact on various device performance parameters. The use of plasmonic back electrodes can impact device performance in a number of ways because the mechanisms of performance improvements are often a complex combination of optical, electrical, and structural effects. Inverted bulk heterojunction device architectures have been shown to benefit from the multifunctionality of plasmonic back electrodes as they can minimize space-charge effects and reduce hole carrier collection lengths in addition to providing improved light localization in the active layer. The use of semi-transparent plasmonic electrodes can also be beneficial for organic photovoltaics as they can exhibit a variety of optical properties such as light scattering, light localization, extraordinary transmission of light, and absorption-induced transparency, in addition to providing an alternative to metal oxide-based transparent electrodes.

Petoukhoff, Christopher E.; Shen, Zeqing; Jain, Manika; Chang, AiMei; O'Carroll, Deirdre M.

2015-01-01

422

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

423

Subsidiarity and Transparency  

Microsoft Academic Search

Subsidiarity and transparency are entirely different concepts. However different, both concepts are twins in the continuing quest of the Framers of European integration to increase the legitimacy of Community decision-making vis--vis the citizens. Indeed, there always has been, and there still is a very serious problem of lack of legitimacy. Increasing the powers of the European Parliament is

Christian Timmermans

1998-01-01

424

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

425

Wearable solar cells by stacking textile electrodes.  

PubMed

A new and general method to produce flexible, wearable dye-sensitized solar cell (DSC) textiles by the stacking of two textile electrodes has been developed. A metal-textile electrode that was made from micrometer-sized metal wires was used as a working electrode, while the textile counter electrode was woven from highly aligned carbon nanotube fibers with high mechanical strengths and electrical conductivities. The resulting DSC textile exhibited a high energy conversion efficiency that was well maintained under bending. Compared with the woven DSC textiles that are based on wire-shaped devices, this stacked DSC textile unexpectedly exhibited a unique deformation from a rectangle to a parallelogram, which is highly desired in portable electronics. This lightweight and wearable stacked DSC textile is superior to conventional planar DSCs because the energy conversion efficiency of the stacked DSC textile was independent of the angle of incident light. PMID:24789065

Pan, Shaowu; Yang, Zhibin; Chen, Peining; Deng, Jue; Li, Houpu; Peng, Huisheng

2014-06-10

426

Optical properties of metamaterial serpentine metal electrodes  

NASA Astrophysics Data System (ADS)

We develop a model to describe the optical properties of periodic surpentine structures in the metamaterial regime. The structures are essentially transparent to infrared radiation and would be useful for transparent electrodes. The model predictions for the absorptance and the reflectance of the serpentine structures show a good agreement with numerical calculations of Maxwell's equations. Our model reveals that the absorptance of the serpentine structures is determined by the self-inductance and the reflectance is affected by both the self-inductance and the effective conductivity. The effective conductivity is shown to be a dominant effect to reduce reflection.

Han, Sang Eon; Clark, Samuel M.

2014-12-01

427

Introduction Transparent conducting oxides (TCOs)  

E-print Network

Introduction Transparent conducting oxides (TCOs) have been known and employed tech- nologically of transparent conductivity continues to ex- pand and promises a pathway to dramat- ically improved materials and Thin- Film Strategies for New Transparent Conducting Oxides A.J. Freeman, K.R. Poeppelmeier, T.O. Mason

Poeppelmeier, Kenneth R.

428

EDITORIAL: On display with transparent conducting films On display with transparent conducting films  

NASA Astrophysics Data System (ADS)

Transparent conducting films were already featuring in scientific literature over one hundred years ago. In 1894 Aryton and Mather described a conducting varnish for coating the screens of electric apparatus so they would not charge when accidentally brushed by a coat sleeve or other material [1]. Their method began with a similar approach to that used to make savoury jellies; by dissolving gelatine in vinegar, after which less palatable ingredients were incorporated including sulphuric acid and an antisulphuric enamel. While the search for transparent conducting films continued to attract other researchers, the same problem remained: the transparency would be compromised if the film was too thick, and the conductivity would be compromised if the film was too thin. In the early 1950s Gillham and Preston reported that thin gold films sputtered on bismuth oxide and heated resulted in a material that successfully combined the previously mutually exclusive properties of transparency and conductivity [2]. Other oxide films were also found to favourably combine these properties, including tin oxide, as reported by Ishiguro and colleagues in Japan in 1958 [3]. Today tin oxide doped with indium (ITO) has become the industry standard for transparent conducting films in a range of applications including photovoltaic technology and displays. It is perhaps the mounting ubiquity of electronic displays as a result of the increasingly digitised and computerised environment of the modern day world that has begun to underline the main drawback of ITO: expense. In this issue, a collaboration of researchers in Korea present an overview of graphene as a transparent conducting material with the potential to replace ITO in a range of electronic and optoelectronic applications [4]. One of the first innovations in optical microscopy was the use of dyes. This principle first came into practice with the use of ultraviolet light to reveal previously indistinguishable features. As explained by a researcher in the early 1930s, 'It is obvious that if the dyes used for selective staining in ordinary microscopical work are supplemented by substances which cause a particular detail of the structure to fluoresce with a specific colour in ultraviolet light, then many strings will be added to the bow of the practical microscopist' [3]. More recently, emphasis on the role of plasmonscollective oscillations of electrons in nanoscale metal structureshas received considerable research attention. Plasmons enhance the local electromagnetic field and can lead to increased fluorescence rates from nearby fluorophores depending on the efficiency of the counteracting process, non-radiative transfer [4]. Flat ITO films have been used extensively in photovoltaic studies as transparent electrodes [5]. Over the past few years, nanowire structures have recently been used to increase the surface area of the interface between dye and oxide in dye-sensitized solar cells [6]. A collaboration of researchers in China and Australia has recently extended the innovation of the nanowire structure to the ITO electrode [7]. Using cyclic voltammetry the researchers confirmed that using a 3D ITO-nanowire electrode significantly enhanced the reaction current. Despite its attractive properties, alternatives to ITO are now in high demand. The rise in devices requiring flat electronic displays has begun to overwhelm the legitimacy of using such a rare element as indium for transparent conducting films. ITO is also brittle, causing problems for flexible displays. Films of carbon nanotubes have been proposed for transparent conducting films but improvements to the sheet resistance are needed before they can compete with the performance of ITO. The effects of HNO3 treatment on the resistivity of carbon nanotube films has attracted some debate in the community, and stimulated the work of Ji-Beom Yoo and colleagues in Korea [8]. Their results suggest that p-type doping has a larger effect on the sheet resistance of HNO3 treated carbon-nanotube films than the removal of residual N-methylpy

Demming, Anna

2012-03-01

429

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

430

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

431

Transparency microplates under impact.  

PubMed

Transparency microplates enable biochemical analysis in resource-limited laboratories. During the process of transfer, the analytes tittered into the wells may undergo spillage from one well to another due to lateral impact. Sidelong impact tests conducted found the absence of non-linear effects (e.g., viscoelastic behavior) but high energy loss. Finite element simulations conducted showed that the rectangular plate holding the transparencies could undergo z-axis deflections when a normal component of the force was present despite constraints being used. High speed camera sequences confirmed this and also showed the asymmetrical z-axis deflection to cause the contact line closer to impact to displace first when the advancing condition was exceeded. Capillary waves were found to travel toward the contact line at the opposite end, where if the advancing contact angle condition was exceeded, also resulted in spreading. The presence of surface scribing was found to limit contact line movement better. With water drops dispensed on scribed transparencies, immunity from momentum change of up to 9.07 kgm/s on impact was possible for volumes of 40 ?L. In the case of glycerol drops immunity from momentum change of up to 9.07 kgm/s on impact extended to volumes of 90 ?L. The improved immunity of glycerol was attributed to its heightened dampening characteristics and its higher attenuation of capillary waves. Overall, scribed transparency microplates were able to better withstand spillage from accidental impact. Accidental impact was also found not to cause any detrimental effects on the fluorescence properties of enhanced green fluorescent protein samples tested. PMID:24863765

Lau, Chun Yat; Roslan, Zulhanif; Cheong, Brandon Huey-Ping; Chua, Wei Seong; Liew, Oi Wah; Ng, Tuck Wah

2014-07-15

432

Transparent Conducting Oxides  

Microsoft Academic Search

In the interim between the conception of this issue of MRS Bulletin on transpar- ent conducting oxides (TCOs) and its pub- lication, the remarkable applications dependent on these materials have contin- ued to make sweeping strides. These in- clude the advent of larger flat-screen high-definition televisions (HDTVs), larger and higher-resolution screens on portable computers, the increasing importance of low emissivity

David S. Ginley

433

Transparency of Computational Intelligence Models  

NASA Astrophysics Data System (ADS)

This paper introduces the behaviour of transparency of computational intelligence (CI) models. Transparency reveals to end users the underlying reasoning process of the agent embodying CI models. This is of great benefit in applications (e.g. data mining, entertainment and personal robotics) with humans as end users because it increases their trust in the decisions of the agent and their acceptance of its results. Our integrated approach, wherein rules are just one of other transparency factors (TF), differs from previous related efforts which have focused mostly on generation of comprehensible rules as explanations. Other TF include degree of confidence measure and visualization of principal features. The transparency quotient is introduced as a measure of the transparency of models based on these factors. The transparency enabled generalized exemplar model has been developed to demonstrate the TF and transparency concepts introduced in this paper.

Owotoki, Peter; Mayer-Lindenberg, Friedrich

434

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

435

Single-walled carbon nanotube transparent conductive films fabricated by reductive dissolution and spray coating for organic photovoltaics  

NASA Astrophysics Data System (ADS)

Solutions of unbundled and unbroken single-walled carbon nanotubes have been prepared using a reductive dissolution process. Transparent conductive films spray-coated from these solutions show a nearly twofold improvement in the ratio of electrical conductivity to optical absorptivity versus those deposited from conventional aqueous dispersions, due to substantial de-aggregation and sizable nanotube lengths. These transparent electrodes have been utilized to fabricate P3HT-PCBM organic solar cells achieving power conversion efficiencies up to 2.3%, comparable to those of solar cells using indium tin oxide transparent electrodes.

Ostfeld, Aminy E.; Catheline, Amlie; Ligsay, Kathleen; Kim, Kee-Chan; Chen, Zhihua; Facchetti, Antonio; Fogden, Sin; Arias, Ana Claudia

2014-12-01

436

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

437

The most transparent research.  

PubMed

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 of peering into our tissues may sound like science fiction, but one day it could be science. Using ideas from genetics, electrical engineering, chemistry and solid-state physics, a handful of researchers are working on ways to render biological tissues transparent.Some have already succeeded: in 2007, Richard White, a biologist at the Dana Farber Cancer Institute in Boston, used careful breeding techniques to create a transparent adult zebrafish named casper, evoking a reference to the famous cartoon ghost by the same name. Now, more than 100 labs around the world are using these transparent fish to study cancer pathology and development in real time. "The field of in vivo imaging-looking at things that are happening inside an actual organism-is growing rapidly," White says.Researchers are even making strides toward turning human tissue transparent. The primary reason we can't see what's inside of us is that light scatters when it passes through tissue. The body is densely packed with many types of substances, such as bone and fat, and light travels through them at different speeds because they have what physicists refer to as different refractive indices. The result is that light can't pass through biological tissues in a straight line, much as car headlights don't pass through dense fog. To fix this problem, scientists are working on developing ways to stop tissues from scattering light. Indeed, "if you take away the scattering properties of human tissues, we would look more or less like jellyfish," explains Changhuei Yang, an electrical engineer and bioengineer at the California Institute of Technology.Though their approaches (described in the following pages) are diverse, these researchers share the common goal of making it one day possible to see what's going on deep inside of the body-a feat that would provide new insights into our biology and help doctors diagnose and treat disease much more easily. "We're trying to push the limits in terms of what can we uncover," says Bernard Choi, a bioengineer at the University of California-Irvine. PMID:19812559

Wenner, Melinda

2009-10-01

438

Evaluation of Solution-Processed Reduced Graphene Oxide Films as Transparent Conductors  

Microsoft Academic Search

Processable, single-layered graphene oxide (GO) is an intriguing nanomaterial with tremendous potential for electronic applications. We spin-coated GO thin-films on quartz and characterized their sheet resistance and optical transparency using different reduction treatments. A thermal graphitization procedure wasmosteffective,producingfilmswithsheetresistancesaslowas102103\\/squarewith80%transmittance for 550 nm light. Our experiments demonstrate solution-processed GOfilms have potential as transparent electro