• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.293-298
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• 2011

The most widely used method to form an electrode in industrial solar cells are screen printing. Screen printing is characterized by a relatively simple and well-known production sequence with high throughput rates. However the method is difficult to implement a fine line width of high-efficiency solar cells can not be made. The open circuit voltage(Voc) and the short circuit current density(Jsc) and fill factor(FF) need to be further improved to increase the efficiency of silicon solar cells. In this study, gravure offset printing method using the multicrystalline-silicon solar cells were fabricated. Gravure off-set printing method which can print the fine line width of finger electrode can have the ability reduce the shaded area and increase the Jsc. Moreover it can make a high aspect ratio thereby series resistance is reduced and FF is increased. Approximately $50{\mu}m$ line width with $35{\mu}m$ height was achieved. The efficiency of gravure off set was 0.7% higher compare to that of scree printing method.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1311-1316
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• 2007

To develop photo-sensitizers for dye-sensitized solar cells (DSCs) used in harvesting sunlight and transferring solar energy into electricity, we synthesize novel Ru(II) polypyridyl dyes and describe their characterization. We also investigate the photo-electrochemical properties of DSCs using these sensitizers. New dyes contain chromophore unit of dafo (4,5-diazafluoren-9-one) or phen-dione (1,10-phenanthroline-5,6-dione) instead of the nonchromophoric donor unit of thiocyanato ligand in cis-[RuII(dcbpy)2(NCS)2] (dcbpy = 4,4'-dicarboxy- 2,2'-bipyridine) coded as N3 dye. For example, the photovoltaic data of DSCs using [RuII(dcbpy)2(dafo)](CN)2 as a sensitizer show 6.85 mA/cm2, 0.70 V, 0.58 and 2.82% in short-circuit current (Jsc ), open-circuit voltage (Voc), fill factor (FF) and power conversion efficiency (Eff), which can be compared with those of 7.90 mA/ cm2, 0.70 V, 0.53 and 3.03% for N3 dye. With the same chelating ligand directly bonded to the Ru metal in the complex, the CN ligand increases the Jsc value by double, compared to the SCN ligand. The extra binding ability in these new dyes makes them more resistant against ligand loss and photo-induced isomerization within octahedral geometry.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.415-418
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• 2014

Phenyltrimethoxysilane (PTMS) was anchored onto the sensitized $TiO_2$ nanoparticles. This insulating molecular layer effectively inhibited the charge recombination at the interface of $TiO_2$/electrolyte in the dye-sensitized solar cells (DSCs) without sacrificing the dye-loading capacity of the nanocrystalline $TiO_2$. DSCs using PTMS-modified $TiO_2$ exhibited a short-circuit current ($J_{SC}$) of $15.9mA/cm^2$, an open-circuit voltage ($V_{OC}$) of 789 mV, and a fill factor (FF) of 68.2%, yielding an overall conversion efficiency (${\eta}$) of 8.55% under $100mW/cm^2$ illumination. The resulting cell efficiency was improved by ~10% as compared with the reference cell.

• Macromolecular Research
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• v.16 no.5
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• pp.424-428
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• 2008

We prepared an ionic gel polymer electrolyte for dye-sensitized solar cells (DSSCs) without leakage problem. Triiodide compound (BTDI) was synthesized by the reaction of benzene tricarbonyl trichloride with diethylene glycol monotosylate and subsequent substitution of tosylate by iodide using NaI. Bisimidazole was prepared by the reaction of imidazole with the triethylene glycol ditosylate under strongly basic condition provided by NaH. BTDI and bisimidazole dissolved in an ionic liquid were injected into the cells and permeated into the $TiO_2$ nanopores. In situ crosslinking was then carried out by heating to form a network structure of poly(imidazolium iodide), thereby converting the ionic liquid electrolytes to a gel or a quasi-solid state. A monomer (BTDI and bisimidazole) concentration in the electrolytes of as low as 30 wt% was sufficient to form a stable gel type electrolyte. The DSSCs based on the gel polymer electrolytes showed a power conversion efficiency of as high as 1.15% with a short circuit current density of $5.69\;mAcm^{-2}$, an open circuit voltage of 0.525 V, and a fill factor of 0.43.

• Solar Energy
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• v.8 no.1
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• pp.41-48
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• 1988

Heterojunction solar cells of $n-Cd_{1-x}Zn_xS/p-Si$ were fabricated by solution growth technique. The crystal structure, spectral response, surface morphology, and I-V characteristics of the $n-Cd_{1-x}Zn_xS/p-Si$ heterojunction solar cells were studied. The $Cd_{1-x}Zn_xS$ layer deposited on a silicon substrate (111) were found to be a cubic structure with the crystal orientation (111), (220) of the CdS and to be a hexagonal structure with crystal orientation (100) of the ZnS. The open-circuit voltage, short-circuit current, fill factor, and conversion efficiency of $n-Cd_{1-x}Zn_xS/p-Si$ heterojunction solar cell under $100mW/cm^2$ illumination were found to be 0.43V, 38mA. 0.76, and 12.4%, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.192-192
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• 2013

본 연구에서는 RF/DC 마그네트론 스퍼터링 시스템을 이용하여co-sputtering 방법으로 성장시킨 고이동도를 갖는Ge-doped $In_2O_3$In2O3 (IGO) 박막의 전기적, 광학적, 구조적 특성을 평가하고, 이를 유기태양전지와 유기발광다이오드에 적용함으로써 고이동도 IGO 투명전극의 소자 적용가능성을 타진하였다. GeO2 타겟에 인가되는 도핑 Power와 급속열처리 온도가 30 W, $500^{\circ}C$일 때, 최적화 된 IGO 박막으로부터 $2.8{\times}10^{-4}$ Ohm-cm의 낮은 비저항과 86.9% (550 nm)의 높은 투과도를 확보하였다. 뿐만 아니라 Near Infra-red (750~1,200 nm) 영역에서의 IGO투명전극의 광투과율이 결정질의 ITO보다 높은(약15%) 투과도를 보이는 것을 통해 IGO박막의 높은 LAS (Lewis Acid Strength) 값을 가지는 Ge 원소의 도핑이 NIR 영역의 광투과율 향상에 미치는 영향을 확인할 수 있었다. 최적 조건의 IGO 박막을 적용하여 Fill Factor 67.38%, Short circuit current density 8.43 mA/cm2, open circuit voltage 0.60 V, efficiency 3.44%의 유기태양전지 및 19.24%의 외부양자효율을 갖는 유기발광다이오드를 제작함으로써 결정질 ITO 전극(20.05%)을 대체할 수 있는 고투과, 고이동도 IGO 투명 전극 및 이를 이용한 광전소자 적용 가능성을 타진하였다.

• Current Photovoltaic Research
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• v.5 no.4
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• pp.135-139
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• 2017

We fabricated two different transparent conducting oxide thin films of ZnO doped with Ga ($Ga_2O_3$ 0.9 wt%) as well as Al ($Al_2O_3$ 2.1 wt%) (GAZO) and ZnO doped only with Al ($Al_2O_3$ 3 wt%) (AZO). It was investigated how it affects the moisture resistance of the transparent electrode. In addition, $Cu(In,Ga)Se_2$ thin film solar cells with two transparent oxides as front electrodes were fabricated, and the correlation between humidity resistance of transparent electrodes and device performance of solar cells was examined. When both transparent electrodes were exposed to high temperature distilled water, they showed a rapid increase in sheet resistance and a decrease in the fill factor of the solar cell. However, AZO showed a drastic decrease in efficiency at the beginning of exposure, while GAZO showed that the deterioration of efficiency occurred over a long period of time and that the long term moisture resistance of GAZO was better.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.257-261
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• 2007

The electronic properties of quantum dots can be tuned by changing the size of particles without any change in their chemical composition. CdSe quantum dots, the sizes of which were controlled by changing the concentrations of Cd and Se precursors, were adsorbed on $TiO_2$ photoelectrodes and used as sensitizers for photovoltaic cells. For applications of CdSe quantum dot as sensitizers, $CdSe/TiO_2$ films on conducting glass were employed in a sandwich-type cell that incorporated a platinum-coated conductive glass and an electrolyte consisting of an $I^-/I_3^-$ redox. The fill factor (FF) and efficiency for energy conversion ($\c{c}$) of the photovoltaic cell was 62 % and 0.32 %, respectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.114-118
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• 2011

Dye-Sensitized Solar Cells(DSSCs) consist of a titanium dioxide($TiO_2$) nano film of the photo electrode, dye molecules on the surface of the $TiO_2$ film, an electrolyte layer and a counter electrode. But two transparent conductive oxide(TCO) substrates are estimated to be about 60[%] of the total cost of the DSSCs. Currently novel TCO-less structures have been investigated in order to reduce the cost. In this study, we suggested a TCO-less DSSCs which has titanium double layer electrodes. Titanium double layer electrodes are formed by electron-beam evaporation method. Analytical instruments such as electrochemical impedance spectroscopy, scanning electron microscope were used to evaluate the TCO-less DSSCs. As a result, the proposed structure decreases energy conversion efficiency and short-circuit current density compared with the conventional DSSCs structure with FTO glass, while internal series impedance of TCO-less DSSCs using titanium double layer electrodes decreases by 27[%]. Consequently, the fill factor is improved by 28[%] more than that of the conventional structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.2
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• pp.178-181
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• 2008

A solar cell based on dye-sensitized photoelectric conversion was studied by investigating the effects of the amount of polyethylene glycol(PEG), added to the $TiO_2$ paste, on surface morphology of the $TiO_2$ films and on the solar cell performance. Energy conversion efficiency was found to increase with PEG addition up to 20 % by weight of $TiO_2$ and then decrease with further addition due to the aggregation of $TiO_2$ nano particles in the $TiO_2$ film. In this study, the best result of dye-sensitized solar cell was the short circuit current(Isc) of $22.6mAcm^{-2}$, the open circuit voltage (Voc) of 0.73 V, the fill factor (ff) of 0.55 and the overall energy conversion efficiency (${\eta}$) of 9.1 % under illumination with AM 1.5 simulated sunlight.