• Membrane Journal
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• v.20 no.1
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• pp.21-28
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• 2010

Organic/inorganic composite electrolyte membranes were prepared for dye sensitized solar cell (DSSC). Poly (ethylene glycol) (PEG)s with various molecular weight (600, 1,500, 2,000 and 3,400) were ethoxysilated to fabricate organic/inorganic composite materials through sol-gel processes. The electrolyte membranes were produced by doping the composite materials with KI and $I_2$, and their ionic conducting behaviors were investigated. The ionic conductivity of the composite membrane was highly affected by PEG molecular weight. The highest conductivity was shown by the composite membrane prepared with PEG with the molecular weight of 2,000. The composite electrolyte membranes showed considerable improvement of ionic conductivity. Compared to PEO electrolyte membranes, the composite electrolyte membrane by PEG, MW 2,000 showed much higher ionic conductivity.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.64.1-64.1
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• 2010

The morphology of mesoporous $TiO_2$ films plays an important role in the operation of a DSSC. For example, the energy conversion efficiency of DSSCs with well-organized mesoporous $TiO_2$ films is much higher than those with traditional films possessing a random morphology. In previous research, well-organized mesoporous $TiO_2$ films have mainly been synthesized using an amphiphilic block copolymer, e.g., a poly(ethylene oxide) (PEO)-based template. A graft copolymer is more attractive than a block copolymer due to its low cost and the ease with which it can be synthesized. In this work, we provide the first report on the successful synthesis of well-organized mesoporous $TiO_2$ films templated by an organized graft copolymer as a structure directing agent. Well-organized mesoporous $TiO_2$ films with excellent channel connectivities were developed via the sol gel processusing an organized PVC-g-POEM graft copolymer synthesized by one-pot ATRP. The careful adjustment of copolymer composition and solvent affinity using a THF/$H_2O$/HCl mixture was used to systematically vary the material structure. The influence of the material structure on solar cell performance was then investigated. A solid-state DSSC employing both the graft copolymer templated organized 700 nm-thick $TiO_2$ films and graft copolymer electrolytes exhibited a solar conversion efficiency of 2.2% at 100 $mW/cm^2$. This value was approximately two-fold higher than that attained from a DSSC employing a random mesoporous $TiO_2$ film. The solar cell performance was maximized at 4.6% when the film thickness was increased to $2.5{\mu}m$. We believe that this graft copolymer-directed approach introduces a new and simple route toward the synthesis of well-organized metal oxide films as an alternative to a conventional block copolymer-based template.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.241-241
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• 2010

Recently high and persistent spontaneous buildup of a surface potential (SP) upon vacuum deposition of tris (8-hydroxyquinolinato) aluminum (III) ($Alq_3$), which is widely used for organic light emitting devices. The removal of the giant surface potential by visible light irradiation has also been reported. In this study, we coated $Alq_3$ on the FTO substrate and raise the capacity for absorbing sun light. The $Alq_3$ which is green light emitting diode emits light at wavelengths between 500 and 550nm. If we apply one's FTO/$Alq_3$ substrate in one's DSSC, we could get higher energy conversion efficiency because the N719 dye that we used for fabricating the DSSC emits light just at near 540nm. The energy conversion efficiency of approximately 4.8 % at the condition of irradiation of AM 1.5 (100 mW/$cm^2$) simulated sunlight, and the $J_{sc}$ is 12.0 mA/$cm^2$, $V_{oc}$ is 0.71 V, FF is 0.56, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.6
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• pp.571-575
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• 2005

In order to improve the efficiency of dye-sensitized solar cell (DSSC), $TiO_2$ electrode screen-printed on transparent conducting oxide (TCO) substrate was sintered in variation with different temperature$(350\;to\;550^{\circ}C)$. $TiO_2$ electrode on fluorine doped tin oxide (FTO) glass was assembled with Pt counter electrode on FTO glass. I-V properties of DSSCs were measured under solar simulator. Also, effect of sintering temperature on surface morphology of $TiO_2$ films was investigated to understand correlation between its surface morphology and sintering temperature. Such surface morphology was observed by atomic force microscopy (AFM). Below sintering temperature of $500^{\circ}C$, efficiency of DSSCs was relatively lower due to lower open circuit voltage. Oppositely, above sintering temperature of $500^{\circ}C$, efficiency of DSSCs was relatively higher due to higher open circuit voltage. In both cases, lower fill factor (FF) was observed. However, at sintering temperature of $500^{\circ}C$, both efficiency and fill factor of DSSCs were mutually complementary, enhancing highest fill factor and efficiency. Such results can be explained in comparison of surface morphology with schematic diagram of energy states on the $TiO_2$ electrode surface. Consequently, it was considered that optimum sintering temperature of a-terpinol included $TiO_2$ paste is at $500^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.52 no.2
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• pp.114-118
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• 2015

$V_2O_5-P_2O_5-ZnO-Sb_2O_3$ glasses modified with BaO and $Al_2O_3$ are synthesized as a sealing material for large-scale dye-sensitized solar cells (DSSCs). A compositional study is performed in order to determine the glass that can be sintered below $500^{\circ}C$ with a high chemical stability against the electrolyte. The flow size of the glasses after the heat treatment and the glass stability are increased with the addition of $Al_2O_3$ and BaO, while the glass transition temperature is decreased. After the reaction with the electrolyte at $60^{\circ}C$ for 72 h, the addition of 5 mol% of BaO and 2 mol% of $Al_2O_3$ considerably enhances the chemical stability of the glass. X-ray diffraction (XRD) and scanning electron microscope (SEM) are used to examine the reaction between the electrolyte and glasses. The structural contribution of the additives is also investigated and discussed.

• Korean Journal of Materials Research
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• v.29 no.3
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• pp.183-188
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• 2019

Flexible dye-sensitized solar cells using binder free $TiO_2$ paste for low temperature sintering are developed. In this paste a small amount of titanium gel is added to a paste of $TiO_2$ nanoparticle. Analysis of titanium gel paste prepared at $150^{\circ}C$ shows that it has a pure anatase phase in XRD and mesoporous structure in SEM. The formation of the titanium gel 1-2 nm coated layer is confirmed by comparing the TEM image analysis of the titanium gel paste and the pristine paste. This coating layer improves the excited electron transfer and electrical contact between particles. The J-V curves of the organic binder DSSCs fabricated at $150^{\circ}C$ shows a current density of $0.12mA/cm^2$ and an open-circuit voltage of 0.47 V, while the titanium gel DSSCs improves electrical characteristics to $5.04mA/cm^2$ and 0.74 V. As a result, the photoelectric conversion efficiency of the organic binder DSSC prepared at low temperature is as low as 0.02 %, but the titanium gel paste DSSCs has a measured effciency of 2.76 %.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.4
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• pp.419-425
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• 2017

In this study, an efficient dye-sensitive solar cells (DSSC) was developed after post-treatment of ZnO on $TiO_2$ photoelectrode. The $TiO_2$ electrode with ZnO post treatment was prepared with Titanium isoporopoxide in Zinc Nitrate Hexahydrate aqueous solution by incineration for 30 min at $450^{\circ}C$. The ZnO-post treated $TiO_2$ electrode showed strong dispersion force between particles in relation to the control $TiO_2$, referring high specific surface area and dye-adsorption rate. Proper addition of ZnO enhanced electron mobility and reduced internal resistance and electron recombination. Light conversion efficiency of DSSCs containing the ZnO-posttreated $TiO_2$ electrode increased 35.4% when compared to the DSSCs using $TiO_2$ electrode. It is similar to the DSSCs with $TiCl_4$ post treatment $TiO_2$ electrode. Increasing of light conversion efficiency was due to high specific surface area and dispersion force, and low dye-adsorption rate and electron recombination. Taken together, ZnO may be used as posttreatment of photoelectrode and replaced $TiCl_4$ that has high toxicity and causticity.

• Journal of the Korean Electrochemical Society
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• v.13 no.1
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• pp.1-9
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• 2010

We are presenting an overview of a R&D trend on dye-sensitized solar cells and organic polymer solar cells, which are classified into a next-generation solar cell, and the perspective on their hybridization technology. When considering the competition with inorganic material-base solar cells, especially, these next-generation solar cells need a new hybridization technology, even though it is still at the initial stage. The fusion and hybridization of them will be not only attractive in a new application, but also promising to expect significant progresses in the near future for successful R&D.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.381-382
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• 2008

We investigated the properties of DSSC by $TiO_2$-blocking layer formed at several annealing temperatures. At $300^{\circ}C$ and $600^{\circ}C$ anatase and rutile phase of $TiO_2$ were formed, respectively. The characteristics of DSSC was improved by blocking layer annealed at $600^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.24-24
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• 2009

투명전극 (TCO Transparent Conductive Oxide)은 Solar cell, Touch panel, Sensor 등 많은 분야에 이용되어지고 있다. ZnO 그리고 $SnO_2$는 ITO룰 대체하기 위하여 오래전부터 연구가 되어지고 있다. 하지만 ZnO가 가지고 있는 많은 장점에도 불구하고 ITO를 대체하기 위한 전기적 특성이 충분하지 않다. 따라서 ZnO에 Al를 도핑하는 등 다양한 연구가 진행되어왔다. 본 실험은 우수한 광학특성 및 전기적 (10-5) 특성을 확보하기 위하여 AZO/Ag/AZO 다층박막구조 형성하였다. 또한 염료감응 태양전지에 적용하기 위하여 다층박막구조를 이용한 안정성 테스트를 진행하였다.