• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2553-2559
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• 2011

Two novel quinacridone (QNC) dyes with thiophene or benzene-conjugated bridge and cyanoacrylic acid acceptor were first designed and synthesized for use in dye-sensitized solar cells (DSSCs). The absorption spectra, electrochemical and photovoltaic properties of these dyes were investigated. Under simulated AM 1.5G irradiation conditions, the solar cell based on the quinacridone dye containing thiophene as a bridge unit had a short-circuit photocurrent density of 8.51 $mA{\cdot}cm^{-2}$, an open-circuit voltage of 643.6 mV, and a fill factor of 0.70, corresponding to an overall conversion efficiency of 3.86%.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.119.2-119.2
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• 2011

Dye-sensitized solar cells (DSSC) are currently attracting wide spread academic and commercial interest for the conversion of sunlight into electricity because of their easy manufacturing process and high efficiency. The solar energy conversion efficiencies of DSSC are strongly dependent on dye molecules adsorbed on the TiO2 surface which used for photosensitization of sun light, since an excited state of dye could inject an electron into the conduction band of semiconductor. We have developed novel organic dyes which have phenothiazine moieties as an electron donor in their charge-transfer chromophore for application of DSSCs. We had synthesized a series of phenothiazine derivatives which have different wave length absorbing chromophore in the molecule with high molar extinction coefficient. The photovoltaic performance of DSSC composed of organic chromophores with broad wavelength absorption property were measured and evaluated by comparison with that of pristine ruthenium dye.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.239.1-239.1
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• 2011

Dye sensitized solar cells (DSC) are promising devices for inexpensive, nontoxic, transparent, and large-scale solar energy conversion. Generally thick $TiO_2$ nanoporous films act as efficient photoanodes with their large surface area for absorbing light. However, electron transport through nanoparticle networks causes the slowdown and the loss of electron transport because of a number of interparticle boundaries inside the conduction path. We have studied DSCs with precisely dimension-controlled $TiO_2$ nanotubes array as photoanode. $TiO_2$ nanotubes array is prepared by template-directed fabrication method with atomic layer deposition. Well-ordered nanotubes array provides not only large surface area for light absorbing but also direct pathway for electrons with minimalized grain boundaries. Large enlongated anatase grains in the nanotubes could enhance the conductivity of electrons, but also suppress the recombination with holes through defect sites during diffusion into the electrode. To study the effect of grain boundaries, we fabricated two kinds of nanotubes which have different grain sizes by controlling deposition conditions. And we studied electron conduction through two kinds of nanotubes with different grain structures. The solar cell performance was studied as a function of thickness and grain structures. And overall solar-to-electric energy conversion efficiencies of up to 7% were obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.134-134
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• 2009

We studied electrochemical properties of $TiO_2$ photoelectrode based graphene for dye-sensitized solar cells(DSSC). Gaphene has good electric conductivity and it is very good transparent when this is coated on monolayer. we prepared photoelectrode by squeeze methode and researched photoelectrical properties of $TiO_2$ electrode base gaphene. DSSC based on graphene was obtained conversion efficiency of 5.4% under irradiation of AM 1.5(100 $mWcm^2$).

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.419-421
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• 2008

Sputter deposition on a Pt counter electrode was studied using RF plasma as the improvement of conversion efficiency for dye-sensitized solar cells (DSC). The effects of the sputtering thickness and incident angle on a Pt counter electrode for DSC was scrutinized. We conducted the experiment to get the optimal sputtering time for the performance of the DSC. Under the sputtering time condition of 120 seconds, we varied the incident angles of substrate from $0^{\circ}$ to $60^{\circ}$. Under standard test condition (AM 1.5, 100mW/$cm^2$), we obtained the maximum efficiency of 4.61% at the incident angle of $40^{\circ}$ with an active cell area of $1cm^2$.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1074_1075
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• 2009

A new type of dye-sensitized solar cells(DSCs) based on Ti-mesh electrode without using TCO layer is fabricated for high-efficient low-cost solar cell application. The TCO-less DSCs sample is composed of a [glass/ dye sensitized $TiO_2$ layer/ Ti-mesh electrode/ electrolyte/ metal counter electrode]. The Ti-mesh electrode with high conductivity can collect electrons from the $TiO_2$ layer and allows the ionic diffusion of $I^-/I_3^-$ through the mesh hole. Thin Ti-mesh ($\sim40{\mu}m$ in thickness) electrode material is processed using rapid prototype method. Electrical performance of as-fabricated DSCs is presented and discussed in detail.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.160-160
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• 2013

Dye-sensitized solar cells (DSSCs) have attracted much attention because of their moderate light-to-electricity conversion efficiency, easy fabrication, and low cost. At present, platinum (Pt) is used as a counter electrode in DSSCs. However, it is found that Pt dissolves in iodide electrolyte solutions and creates chemical compound such as PtI4 and H2PtI6. Carbon based materials are one of candidates for a counter electrode of DSSCs. We prepare two types of graphite oxides by different chemical treatments; original graphite oxide, hydrazine treated graphite oxide. Each graphite oxide and magnesium nitrate dispersed in deionized water are prepared as solutions for electrophoretic deposition (EPD). Each graphite oxide electrode is deposited on fluorine-doped tin oxide (FTO) substrate by EPD method. Structural and electrochemical properties of each electrode are investigated by field-emission scanning electron microscopy and electrochemical impedance spectroscopy, respectively.

• 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.

• 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.

• Journal of Integrative Natural Science
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• v.2 no.4
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• pp.237-242
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• 2009

As semitransparent dye-sensitized solar cells (DSSCs) have advanced to large-scale applications from lab-level research, the large-scale performance has attracted much attention. Modules of DSSCs have been investigated to optimize the efficiency as a $TiO_2$ systhesis temperature and a surface treatment of $TiCl_4$ aqueous solution. Essentially, these semitransparent modules have an extended structure with lab-scale works with the exception of the dimensions and methods for the series connection. The $5cm{\times}6.5cm$ modules have shown an efficiency of about 6% without a scattering layer. While the fill factors of modules depend on the width of each $TiO_2$ unit cell, they are much less dependent on the lengths of the unit cells.