• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.484.2-484.2
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• 2014

There are many efforts to improving the power conversion efficiencies (PCEs) of dye-sensitized solar cells (DSCs). Although DSCs have a low production cost, their low PCE and low thermal stability have limited commercial applications. This study describes the preparation of a novel multifunctional polymer gel electrolyte in which a cross-linking polymerization reaction is used to encapsulate $TiO_2$ nanoparticles toward improving the power conversion efficiency and long-term stability of a quasi-solid state DSC. A series of liquid junction dye-sensitized solar cells (DSCs) was fabricated based on polymer membrane encapsulated dye-sensitized $TiO_2$ nanoparticles, prepared using a surface-induced cross-linking polymerization reaction, to investigate the dependence of the solar cell performance on the encapsulating membrane layer thickness. The ion conductivity decreased as the membrane thickness increased; however, the long term-stability of the devices improved with increasing membrane thickness. Nanoparticles encapsulated in a thick membrane (ca. 37 nm), obtained using a 90 min polymerization time, exhibited excellent pore filling among $TiO_2$ particles. This nanoparticle layer was used to fabricate a thin-layered, quasi-solid state DSC. The thick membrane prevented short-circuit paths from forming between the counter and the $TiO_2$ electrode, thereby reducing the minimum necessary electrode separation distance. The quasi-solid state DSC yielded a high power conversion efficiency (7.6/8.1%) and excellent stability during heating at $65^{\circ}C$ over 30 days. These performance characteristics were superior to those obtained from a conventional DSC (7.5/3.5%) prepared using a $TiO_2$ active layer with the same thickness. The reduced electrode separation distance shortened the charge transport pathways, which compensated for the reduced ion conductivity in the polymer gel electrolyte. Excellent pore filling on the $TiO_2$ particles minimized the exposure of the dye to the liquid and reduced dye detachment.

• 전기전자학회논문지
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• 제23권2호
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• pp.538-542
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• 2019

광 전환 효율에 관여하는 $TiO_2$와 같은 반도체 산화물은 염료 감응 태양전지(Dye-sensitized solar cell, DSSC)의 주요 요소이며, 효율을 개선하기 위해 서로 다른 반도체 산화물을 혼합하여 Pastes를 제조해 사용하는 연구가 이루어지고 있다. 본 연구에서는 $TiO_2-Nb_2O_5$ 혼합 반도체 산화물을 제조하여 염료 감응 태양전지의 특성을 분석하였다. 혼합 반도체 산화물이 광 전환 효율에 미치는 전기적인 특성을 분석하기 위해서 $Nb_2O_5$을 서로 다른 비율로 첨가하여 태양전지를 제작하였다. 이에 $Nb_2O_5$가 첨가됨에 따라 전해질과의 접촉에 의한 재결합 현상보다 전도성이 겅화되어 태양전지의 단락 전류, 개방전압, 변환 효율 등이 개선되는 것을 확인하였다.

• Rapid Communication in Photoscience
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• 제4권4호
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• pp.82-85
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• 2015

Photoelectrochemical cell (PEC) is one of the attractive ways to produce clean and renewable energy. However, solar to hydrogen production via PEC system generally requires high external bias, because of material's innate electronic band potential relative to hydrogen reduction potential and/or charge separation issue. For spontaneous photo-water splitting, here, we design dye-sensitized solar cell (DSSC) and their monolithic tandem cell incorporated with a $BiVO_4$ photoanode. $BiVO_4$ has high conduction band edge potential and suitable band gap (2.4eV) to absorb visible light. To achieve efficient $BiVO_4$ photoanode system, electron and hole mobility should be improved, and we demonstrate a tandem cell in which $BiVO_4/WO_3$ film is connected to cobalt complex based DSSC.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.425-427
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• 2008

Active area of dye-sensitized solar cell (DSSC) has an effect on the efficiency of DSSC. As the active area increases, the efficiency goes down in a general way. This is caused by the increase of internal resistance in DSSC. The internal resistances are related to various resistant elements. The charge transfer processes at Pt counter electrode and the sheet resistance of TCO are two of these resistant elements. In this study, we try to divide the active area into several small sections in a large sized cell to reduce these two internal resistant elements. As a result, we find out that the fill factor is increased and then the conversion efficiency is improved as the number of dividing active area into several small sections is increased.

• 전기학회논문지
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• 제56권1호
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• pp.123-127
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• 2007

Up sizing of dye-sensitized solar cell(DSC) is the important technology to bring about commercialization of DSC. Several studies to obtain a stable large area DSC have been investigated in overseas laboratories, but have been hardly done in our country. In this study, up sizing technology of dye sensitized solar cells(DSCs) was investigated. We investigated low dark current materials for the current collecting grid. From the result, a new DSC module with metal grid was designed, and fabricated. For a new interconnection, both working and counter electrodes are alternately coupled on 10[cm]$\times$7[cm] substrate. We have achieved 68% of fill factor and photoelectric conversion efficiency of around 2.6% as the best results of new designed DSC structure.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.220-224
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• 2009

The effect of addition of single and binary additives on the performance of dye-sensitized $TiO_2$ solar cells based on 1,2-dimethyl-3-propylimidazolium iodide (DMPII) in ethylene carbonate (EC) and gamma-butyrolactone (GBL) has been evaluated at different cell temperatures in the $30-120^{\circ}C$ range. The electrolyte containing a single additive, 2-(dimethylamino)-pyridine (DMAP) showed best performance, which showed further enhancement for an electrolyte containing binary additives, DMAP and 5-chloro-1-ethyl-2-methylimidazole (CEMI) in equal molar ratio. The performance of the dye sensitized solar cell (DSC) based on electrolyte containing binary additives were found to be better than an acetonitrile based electrolyte. The dependence of different photovoltaic parameters (Voc, Jsc, ff, n) of the DSC upon temperature has been studied over the $30-120^{\circ}C$ range and only a small decrease in conversion efficiency has been observed. Thus the electrolyte containing binary additives (DMAP, CEMI) in EC/GBL solvent and show better performance in the investigated temperature range ($30-120^{\circ}C$).

• Current Photovoltaic Research
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• 제3권3호
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• pp.91-96
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• 2015

Optical modeling and characterization of transparent dye-sensitized solar cells (DSC) are presented to design and estimate DSC devices numerically. In order to model the inhomogeneous active layer of DSC, the porous structure of titanium oxide ($TiO_2$) and dye mixture, we prepared films consisting of layer by layer of the DSC's basic materials sequentially, and characterized the optical parameters of the films with the effective refractive index, which was extracted from the transmittance and reflectance measurements in ultra violet to near infra-red range. By using the effective refractive index, we made the optical model for DSC, and demonstrated that the optical model based on effective refractive index can be used to design and evaluate the performance of transparent-type DSC modules.

• Journal of Electrochemical Science and Technology
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• 제1권2호
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• pp.69-74
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• 2010

Methodologies to improve photovoltaic performance of dye-sensitized solar cell (DSSC) are reviewed. DSSC is usually composed of a dye-adsorbed $TiO_2$ photoanode, a tri-iodide/iodide redox electrolyte and a Pt counter electrode. Among the photovoltaic parameters of short-circuit photocurrent density, open-circuit voltage and fill factor, short-circuit photocurrent density is the collective measure of light harvesting, charge separation and charge collection efficiencies. Internal quantum efficiency is known to reach almost 100%, which indicates that charge separation occurs without loss by recombination. Thus, light harvesting efficiency plays an important role in improvement of photocurrent. In this paper, technologies to improve light harvesting efficiency, including surface area improvement by nano-dispersion, size-dependent light scattering efficiency, bi-functional nano material, panchromatic absorption by selective positioning of three different dyes and transparent conductive oxide (TCO)-less DSSC, are introduced.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.251-256
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• 2006

To design the effective usage of electric double layer capacitors (EDLCs) used for a storage device of dye sensitized solar cell (DSC) energy, we first investigated the accumulation state of electrical charges and the charge behavior in the EDLCs. Based on the results, the voltage characteristics of EDLCs connected to DSC energy were evaluated. The results showed that the charge accumulation region concentrated on the central part of the carbonaceous electrode in EDLCs and the required times for charging and discharging were almost the same.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
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• pp.673-676
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• 2005

To design the effective usage of electric double layer capacitors (EDLCs) used for a storage device of dye sensitized solar cell(DSC) energy, we first investigated the accumulation state of electrical charges and the charge behavior in the EDLCs. Based on the results. the voltage characteristics of EDLCs connected to DSC energy were evaluated. The results showed that the charge accumulation region concentrated on central part of the carbonaceous electrode in EDLCs and the required times for charging and discharging were almost the same.