• Journal of the Korean institute of surface engineering
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• v.52 no.1
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• pp.1-5
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• 2019

Anodic oxidized $TiO_2$ nanotube arrays are promising materials for application in photoelectrochemical solar cells as the photoanode, because of their attractive properties including slow electron recombination rate, superior light scattering, and smooth electrolyte diffusion. However, because of the opacity of these nanotube electrodes, the back-side illumination is inevitable for the application in solar cells. Therefore, for the fabrication of solar cells with the anodic oxidized nanotube electrodes, it is required to develop efficient and transparent counter electrodes. Here, we demonstrate quantum dot-sensitized solar cells (QDSCs) based on the nanotube photoanode and transparent counter electrodes. The transparent counter electrodes based on Pt electrocatalysts were prepared by a simple thermal decomposition methods. The photovoltaic performances of QDSCs with nanotube photoanode were tested and optimized depending on the concentration of Pt precursor solutions for the preparation of counter electrodes.

• Transactions on Electrical and Electronic Materials
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• v.6 no.4
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• pp.140-143
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• 2005

Carbon Nanotube(CNTs) counter electrode is a promising alternative to Platinum counter electrode for dye sensitized solar cells (DSSCs). In this study, CNT counter electrodes having different visible light transmittance were prepared on fluorine-doped tin oxide (FTO) glass surface by spray coating method. Microstructural images show that there are CNT-tangled region coated on FTO glass counter electrodes. Using such CNT counter electrodes and screen printed $TiO_2$ electrodes, DSSCs were assembled and its I-V characteristics have been studied and compared. Light energy conversion efficiency of DSSCs increased with decreasing in light transmittance of CNT counter electrode. Efficiency of DSSCs having CNT counter electrode is compatible to that of Pt counter electrode.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1579-1583
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• 2008

We proposed the new structure of ac plasma display panel(PDP) to improve the luminous efficacy and driving voltage characteristics. Through two-dimensional numerical simulations, we analyzed the effects of new counter discharge type, which consists of counter sustain electrodes and auxiliary electrodes. Generally, an advantage of AC PDP with the counter sustain electrodes has been known for the driving characteristics of the low voltage. In this work, the new counter structure using the ignition discharge by the auxiliary pulse applied to the address electrode showed the result of the increased luminous efficacy. The short gap discharge between two auxiliary electrodes on the front plate could intensity the long gap discharge between counter electrodes. The reliability of simulation result could be confirmed by the experimental result in the test panel.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.234-234
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• 2013

The counter electrodes in dye-sensitized solar cells (DSSCs) play roles in not only collecting electrons from external circuit but also reducing I3- to I- in electrolytes. Generally, conventional counter electrodes for DSSCs are prepared from the high temperature treatment of the H2PtCl6 precursor solution at $400^{\circ}C$ However, the more simplified fabrication process of counter electrodes is required for the commercialization of DSSCs. In this work, we developed novel fabrication process of counter electrodes using nano-second pulsed laser. DSSCs employing counter electrodes prepared by laser process showed conversion efficiency of 6.75% with short-circuit current of 12.73 mA/cm2, open-circuit voltage of 0.74 V and fill factor of 0.72. Closer investigating of photovoltaic properties will be reported.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.1
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• pp.63-69
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• 2017

In this work, two different platinum (Pt) counter electrodes have been prepared by spin coating a Pt solution and screen printing a Pt paste on fluorine doped tin oxide (FTO) glass substrate followed by sintering at $380^{\circ}C$ for 30 min. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) analyses of the Pt electrodes showed that the spin coated electrode was catalytically more active than the screen printed electrode. The above result agrees well with the surface morphology of the electrodes studied by atomic force microscopy (AFM) and the photovoltaic performance of the dye-sensitized solar cells (DSSCs) fabricated with the Pt electrodes. Moreover, calculation of current density-voltage (j-V) curves according to diode model with the parameters obtained from the experimental j-V curves and the EIS data of the DSSCs provided a quantitative insight about how the catalytic activity of the counter electrodes affected the photovoltaic performance of the cells. Even though the experimental situations involved in this work are trivial, the method of analyses outlined here gives a strong insight about how the catalytic activity of a counter electrode affects the photovoltaic performance of a DSSC. This work, also, demonstrates how the photovoltaic performance of DSSCs can be improved by tuning the performance of counter electrode materials.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.227-228
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• 2012

In interfaces between carbon black or Pt and FTO glass in dye-sensitized solar cell counter electrodes, a marginal resistant channel for electrons, we tried to improve the connection by modifying the sintering process. A stepwise sintering process for carbon black and Pt counter electrodes was applied and its effect on power conversion efficiency was studied. Power conversion efficiencies of built-in DSSC made by a one-step sintering process with carbon black and Pt counter electrodes were about 5.01% and 5.02%, respectively. Cells made with the stepwise sintering process were 5.96% and 6.21%, respectively, indicating an 20% improvement. Fill factor (FF) increased, and it was them main reason for the power conversion efficiency improvement. Step wise sintering increased the adhesion of the interface and reduced the film thickness and surface roughness. As a result, the resistivity of the counter electrode and EIS impedance of DSSCs decreased.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.4
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• pp.337-341
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• 2007

In this paper, we studied counter electrodes that carbon materials is used for dye-sensitized solar cells. Carbon electrodes characterized by changing of CMC wt. %. We investigated a porous structure of electrodes and a specific resistance of carbon electrodes for identification of electric conductivity. The specific resistance of carton electrodes increased by an increase of CMC wt. % and this result affected an efficiency of the cells.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.154-157
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• 2006

The counter electrode widely used in DSCs (Dye-sensitized Solar Cells) is constructed of conducting glass substrates coated with Pt films, where the platium acts as a catalyst. Pt counter electrodes in DSCs are one important component. It is expected that characteristics of Pt electrodes strongly depend on fabrication process and its surface condition. In this study, Pt counter electrode surface of DSC is deposited by reactive RF magnetron sputtering under the conditions of Ar 5mtorr, RF power of 120w and substrate temperature of $100^{\circ}C$. Surface morphology of Pt electrodes was investigated by FE-SEM and AFM. And this paper shows our recent results and technology to fabricate the new designed cell with Pt electrodes deposited by sputtering method. We have achieved fill factor 65% and photoelectric conversion efficiency around 2.6% as the best results of new designed DSCs structure.

• Transactions on Electrical and Electronic Materials
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• v.6 no.5
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• pp.238-242
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• 2005

The Pt counter electrode of a dye-sensitized solar cell (DSSC) plays a role in helping redox reaction of iodine ions in electrolyte, also, transferring electrons into electrolyte. In this case, it is expected that characteristics of Pt electrodes strongly depend on fabrication process and its surface condition. In this study, Pt electrodes were prepared by a electro-deposition and a RF magnetron sputtering. Electrochemical behavior of Pt electrodes was compared using cyclic-voltammetry and impedance spectroscopy. Surface morphology of Pt electrodes was investigated by FE-SEM and AFM. I-V characteristics of DSSC were measured and discussed in association with the surface properties of counter electrode. As a result, electrochemical properties of electro-deposited Pt electrode were superior to that of sputtered Pt electrode. This is likely that enlarged area of surface in electro-deposited Pt electrode in comparison with the case of sputtered Pt electrode playa role in enhancing such electrochemical properties.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.615-616
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• 2005

Carbon Nanotubes (CNT) on flexible indium tin oxide (ITO) PET films were prepared for dye-sensitized solar cell (DSSC). These CNTs were prepared by spray coating method for various amount of light transparency. Also, Pt counter electrode was prepared by electro deposition method. All $TiO_2$ electrodes were deposited on ITO-PET films by spray coating method. Micro structural images show that CNT counter electrodes prepared by spray-coating have more dense structure with increasing spraying time (0 to 60 seconds). DSSC consisting of $TiO_2$ electrode and CNT counter electrode was fabricated with various amount of light absorption. DSSC have higher light energy conversion efficiency with increasing the thickness of CNT counter electrode. CNT counter electrode is at least compatible to that of CNT counter electrode.