• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.187-191
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• 2006

Sputter deposition followed by surface treatment was studied using reactive RF plasma as a method for preparing titanium oxide $(TiO_2)$ films on the FTO $(SnO_2: F)$ substrate for dye-sensitized solar cells (DSCs). Anatase structure $TiO_2$ films deposited by reactive RF magnetron sputtering under the conditions of $Ar/O_2(5%)$ mixtures, RF power of 600W and substrate temperature of $400^{\circ}C$ were surface-treated by inductive coupled plasma (ICP) with $Ar/O_2$ mixtures at substrate temperature of $400^{\circ}C$, and thus the films were applied to the DSCs. We have chosen a solar cell width as a variable of a large-scaled DSCs and confirmed electric characteristics of an individual cell. As a result, the higher the internal resistance of DSC becomes, the wider the width gets. Internal resistance makes it difficult to collect photoelectron generated from dye. Ultimately up sizing DSC causes the increase of internal resistance and then has a bad effect on the cell characteristics.

• Steel and Composite Structures
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• v.27 no.1
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• pp.123-133
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• 2018

Steel-concrete-steel (SCS) sandwich composite structure with corrugated-strip connectors (CSC) has the potential to be used in buildings and offshore structures. In this structure, CSCs are used to bond steel face plates and concrete. To overcome executive problems, in the proposed system by the authors, shear connectors are one end welded as double skin composites. Hence, this system double skin with corrugated-strip connectors (DSCS) is named. In this paper, finite element model (FEM) of push-out test was presented for the basic component of DSCS. ABAQUS/Explicit solver in ABAQUS was used due to the geometrical complexity of the model, especially in the interaction of the shear connectors with concrete. In order that the explicit analysis has a quasi-static behavior with a proper approximation, the kinetic energy (ALLKE) did not exceed 5% to 10% of the internal energy (ALLIE) using mass-scaling. The FE analysis (FEA) was validated against those from the push-out tests in the previous work of the authors published in this journal. By comparing load-slip curves and failure modes, FEMs with suitable analysis speed were consistent with test results.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1485-1486
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• 2011

A layer of $TiO_2$ thin film less than ~500nm in thickness, as a blocking layer, was coated by sol-gel method directly onto the anode electrode to be isolated from the electrolyte in dye-sensitized solar cells (DSCs). This is to prevent the electrons from back-transferring from the electrode to the electrolyte (I-/I3-). The effects of heat treatment conditions of the gel and as-coated film on the thickness and consolidation to substrate were studied. The flexible DSCs were fabricated with working electrode of Ti thin foil coated with blocking $TiO_2$ layer, dye-attached mesoporous $TiO_2$ film, gel electrolyte and counter electrode of Pt-deposited indium doped tin oxide/polyethylene naphthalate (ITO/PEN). The photo-current conversion efficiency of the cell was 5.3% ($V_{oc}=0.678V$, $J_{sc}=12.181mA/cm^2$, ff=0.634) under AM1.5, 100 mW/$cm^2$ illumination.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1430-1431
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• 2011

To develope the transparent conducting oxide(TCO) films is one of the essential technologies to improve various properties of electro-optical devices such as dye-sensitized solar cells(DSCs). ITiO thin film is considered one of the candidates as TCO electrodes of DSCs because it shows many advantages such as the high transparency in long wavelength range above 700nm and excellent properties of electrical necking between nanoporous TiO2 and ITiO transparent electrode. This paper presents the effect of sputtering processes on the structural, electrical and optical properties of ITiO thin film deposited by r.f. magnetron sputtering. The effect of doping concentration of Ti on the chemical compounds and C axis-orientation properties of were mainly studied experimentally. The morphology and electrical properties were greatly influenced by deposition processes, especially by the doping concentration of Ti. The $3.8{\times}10^{-4}{\Omega}{\cdot}cm$ of minimum volume resistivity were obtained under the experimental conditions of gas pressure 7mTorr, substrate temperature $300^{\circ}C$, and 2.5% of Ti doping concentration.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.177-179
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• 2009

In order to investigate the possible application of ZnO films as a transparent conducting oxide (TCO) electrode, ZnO:Al films were prepared by RF magnetron sputtering method. The effects of surface treatment and doping concentration on the structural and electrical properties of ZnO films were mainly studied experimentally. Five-inch PDP cells using either a ZnO:Al or indium tin oxide (ITO) electrode were also fabricated separately under the same manufacturing conditions. The luminous properties of both the transparent conducting oxide electrode were measured and compared with each other. By doping the ZnO target with 2 wt% of Al2O3, the film deposited at a chemical surface treatment resulted in the minimum resistivity of 8.5 _ 10_4 U-cm and a transmittance of 91.7%. And DBD surface treatment resulted in the minimum resistivity of 8.5 _ 10_4 U-cm and a transmittance of 91.7%. Although the luminance and luminous efficiency of the transparent conducting oxide electrode using ZnO:AI are lower than those of the cell with the ITO electrode by about 10%, these values are sufficient enough to be considered for the normal operation of TCO.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1423_1424
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• 2009

Dye sensitized solar cells(DSC) have been very economical and easy method to convert solar energy to electricity. DSC can reach low costs in future outdoor power applications. However, to commercialize the DSC, there are still many shortages to overcome such as a low efficiency in a large size DSC. In this study, DSCs were fabricated by an electrospray coating method for the $TiO_2$ thin film. They were compared with DSCs prepared by conventional coating methods. We conducted an experiment to obtain the optimized parameters of voltage, flow rate, incident angle and distance in the electrospray method. After we manufactured $TiO_2$ film using that way, we could analyze the characteristics of DSC through SEM, UV curve, EIS.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1100-1101
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• 2015

In this work, the effect of addition of acetylacetone on microstructure and quality of nanoporous $TiO_2$ photo-electrodes was studied in dye-sensitized solar cells (DSCs) and structure and electrical properties of fabricated cells were investigated. From the results, the DSCs fabricated with acetyl acetone showed highest photovoltaic performances. This behavior may be attributed to paste agglomeration decrease and interconnection and bonding improvement between $TiO_2$ particles. Furthermore, the most favorable dye absorption time results to be 10h: exceeding this time a decrease in efficiency is observed despite the increasing amount of dye absorption. The $TiO_2$ photo-electrode prepared under the conditions of acetylacetone ratio of 15% and dye absorption time of 10hr showed the better photovoltaic performance ($J_{sc}=12.48mA/cm^2$, $V_{oc}=0.69V$, ff=0.68, ${\eta}=5.86%$).

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.53.2-53.2
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• 2011

Dye-sensitized solar cells(DSSCs) have been recognized as an alternative to the conventional p-n junction solar cells because of their simple fabrication process, low production cost, and transparency. A typical DSSC consists of a transparent conductive oxide (TCO) electrode, a dye-sensitized oxide semiconductor nanoparticle layer, liquid redox electrolyte, and a Pt-counter electrode. In dye-sensitized solar cells, charge recombination processes at interfaces between coducting glass, $TiO_2$, dye, and electrolyte play an important role in limiting the photon-to-electron conversion efficiency. A layer of ZTO thin film less than ~200nm in thickness, as a blocking layer, was deposited by DC magnetron sputtering method directly onto the anode electrode to be isolated from the electrolyte in dye-sensitized solar cells(DSCs). This is to prevent the electrons from back-transferring from the electrode to the electrolyte ($I^-/I_3^-$). The presented DSCs were fabricated with working electrode of Ga-doped ZnO glass coated with blocking ZTO layer, dye-attached nanoporous $TiO_2$ layer, gel electrolyte and counter electrode of Pt-deposited GZO glass. The effects of blocking layer were studied with respect to impedance and conversion efficiency of the cells.

• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.168-174
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• 2009

In this paper Gel polymer electrolyte using Poly(Vdf-HFP) was fabricated and compared with liquid type electrolyte. The chemical structure and ingredients of fabricated gel electrolyte was investigated and identified to gel polymer electrolyte by FTIR, gel electrolyte was verified to polymer state by SEM From the experiment result, the better component ratio of Propylene carbonate and Diethyl carbonate for gel type electrolyte was 5 : 5. The conversion efficiency of fabricated DSCs using gel electrolyte was $3{\sim}4[%]$, expected to alternate with liquid type electrolyte.