• Elastomers and Composites
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• v.47 no.1
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• pp.2-8
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• 2012

In this study, in order to develop renewable bio-based nanocomposites, multi-functional nanocomposites from soybean resins (AESO, MAESO) and nanoclay were prepared. Photoelectrodes for environmental friendly dye-sensitized solar cell using soybean resin were also prepared. Organo-modified nanoclay was directly dispersed in functionalized soybean resins after mixing with styrene as a comonomer and radical initiator was used to copolymerize the nanocomposites. The observed morphology was a mixture of intercalated/exfoliated structure and the physical properties were improved by adding nanoclay. A nanocomposite using MAESO, which added COOH functional group to the soybean resin, showed better dispersibility than AESO composites. Ultrasonic treatment of the nanocomposites also improved the physical properties. Nanoporous $TiO_2$ photoelectrode was also prepared using soybean resins as a binder, after acid-treatment of $TiO_2$ surface using nitric acid. Dye-sensitized solar cells were prepared after adsorbing dye molecules on it. The $TiO_2$ photoelectrode prepared using soybean binder had high current density because of increased surface area by improved dispersibility. The photoelectrochemical properties and conversion efficiency of the solar cell were significantly improved using the soybean binder.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.677-679
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• 2005

최근 나노입자를 이용하는 광전 화학전지(PEC, Photoelectrochemical)인 염료감응형 태양전지(DSC)의 효율이 증가함에 따라 DSC 태양광 발전 시스템의 성능 개선 또한 요구되어진다. 본 연구에서는 Fly-Back DC-DC 컨버터(변화비율1:10)를 이용하여 DSC셀의 전압을 DC 300V로 승압시켰다. 또한 풀브릿지 인버터를 사용하여 AC 220V, 60Hz의 출력전압을 얻었다. 연구에서 제안한 회로는 높은 효율의 동작특성과 간단한 제작, 낮은 제조비용, 그리고 안정성을 추구한다. 또 다른 주요점은 부하단에서 Feed back을 받아 동작을 컨트롤하는 것이다. 부하단의 출력 전압과 전류를 Feed back 받아서 DSP320LF2406을 A/D기능을 사용하여 실시간으로 부하의 변화에 대처하여 컨버터와 인버터의 동작을 제어한다.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.57.2-57.2
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• 2011

Dye-sensitized solar cells (DSSC) have recently been developed as a cost-effective photovoltaic system due to their low-cost materials and facile processing. The production of DSSC involves chemical and thermal processes but no vacuum is involved. Therefore, DSSC can be fabricated without using expensive equipment. The use of dyes and nanocrystalline $TiO_2$ is one of the most promising approaches to realize both high performance and low cost. The efficiency of the DSSC changes consequently in the particle size, morphology, crystallization and surface state of the $TiO_2$. Nanocrystalline $TiO_2$ materials have been widely used as a photo catalyst and an electron collector in DSSC. Front electrode in DSSC are required to have an extremely high porosity and surface area such that the dyes can be sufficiently adsorbed and be electronically interconnected, resulting in the efficient generation of photocurrent within cells. In this study, DSSC were fabricated by an screen printing for the $TiO_2$ thin film. $TiO_2$ nanoparticles characterized by X-ray diffractometer (XRD) and scanning electron microscope (SEM) and scanning auger microscopy (SAM) and zeta potential and electrochemical impedance spectroscopy(EIS).In addition, DSSC module was modeled and simulated using the SILVACO TCAD software program. Improve the efficiency of DSSC, the effect of $TiO_2$ thin film thickness and $TiO_2$ nanoparticle size was investigated by SILVACO TCAD software program.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.381-386
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• 2011

Chemically functionalized plant oils, namely maleinized acrylated epoxidized soybean oil(MAESO), were used as a new bio based binders for photoelectrodes of dye-sensitized solar cells. The photocatalysts were characterized by field emission scanning electron microscope(FE-SEM), energy dispersive X-ray spectrometer(EDS), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and nitrogen adsorption analyses. The surface area and number of appropriate pores were increased in the $TiO_{2}$ particles prepared using the plant oil binders in comparison with the P-25 photocatalyst, due to the larger number of functionalities. The functional groups of OH on the surface of the $TiO_{2}$ particles increased from 9.9% to 16.62%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.4013-4018
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• 2014

A 0.45 $cm^2$ DSSC device with a glass/FTO/blocking layer/$TiO_2$/N719(dye)/electrolyte/50 nm-Pt/50 nm-Au/FTO/glass was prepared to examine the stability of the Au/Pt bilayered counter electrode (CE) with electrolyte and the energy conversion efficiency (ECE) of dye-sensitized solar cells (DSSCs). For comparison, a 100 nm-thick Pt only CE DSSC was also prepared using the same method. The photovoltaic properties, such as the short circuit current density ($J_{sc}$), open circuit voltage ($V_{oc}$), fill factor (FF), and ECE, were checked using a solar simulator and potentiostat with time after assembling the DSSC. The microstructure of the Au/Pt bilayer was examined by optical microscopy after 0~25 minutes. The ECE of the Pt only CE-employed DSSC was 4.60 %, which did not show time dependence. On the other hand, for the Au/Pt CE DSSC, the ECEs after 0, 5 and 15 minutes were 5.28 %, 3.64 % and 2.09 %, respectively. The corrosion areas of the Au/Pt CE determined by optical microscopy after 0, 5, and 25 minutes were 0, 21.92 and 34.06 %. These results confirmed that the ECE and catalytic activity of Au/Pt CE decreased drastically with time. Therefore, a Au/Pt CE-employed DSSC may be superior to the Pt only CE-employed one immediately after integration of the device, but it would degrade drastically with time.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.199-201
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• 2006

A lot of researches and experiments have been performed to make more efficient dye-sensitized solar cell. Among them, insertion of a grid electrode in DSC is one method to increase overall performance as being shortened distance of electrons' movement by diffusion. In this paper, we measured overall characteristics which is included voltage-current characteristic curve, efficiency, fill factor by comparison between DSC without and with grid electrode. As a result, we got maximum 1.8 times increase of efficiency and approximately 1.7 times rise of fill factor. And we experimented 8, 10, 12, 14mm of grid gap and compared their results to optimize grid gap which is able to incite the most effective movement of electrons. Consequently, we got the result that electrons' movement is the most effect ive when grid gap is approximately 12mm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.358-359
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• 2008

Solar cell based on dye-sensitized photoelectric conversion was studied by investigating the effects of the amount of $TiO_2$ nanofiber added to the $TiO_2$ paste, on surface morphology, good electric of the $TiO_2$ films and on the solar cell performance. Energy conversion efficiency was found to increased with $TiO_2$ nanofiber addition up to 7wt% in $TiO_2$ films. Maximum increase upto 15% in the efficiently was observed at 7 wt. % of $TiO_2$ nanofiber in $TiO_2$ electrode.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.308-308
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• 2013

본 연구에 염료감응형 태양전지(Dye Sensitized Solar Cells; DSSCs)의 광전변환효율을 높이기 위해 작업전극에 새로운 구조의 광투과층 및 산란층을 도입하였다. DSSCs 작업전극의 빛을 투과시키는 투과층에 크기가 10 nm 이하의 nanoparticle $TiO_2$를 적용하고, 투과된 빛이 산란되어 많은 전자가 여기 될 수 있도록 기존의 큰 입자 사이즈였던 산란층을 이용하는 대신 $TiO_2$ nanorod 및 nanotube 형태의 구조를 도입하여 기존의 작업전극과 비교하였다. 산란층에서 방향성을 가지는 rutile 상의 $TiO_2$는 저온에서 안정적인 anatase 상의 $TiO_2$보다 화학적으로 안정하며, 높은 산란율을 가지고, 광에 의해 여기된 전자를 직접적으로 집전전극에 전달해 줌으로서 소자의 효율을 증가시킨다고 보고되고 있다. Rutile 상의 $TiO_2$ 층 제작 시 수열합성법을 이용하면 nanorod 모양의 $TiO_2$층을 형성할 수 있고, 이와 같은 방법으로 성장시킨 산란층에 전기영동법의 식각 효과를 사용하면 nanotube 모양의 $TiO_2$층을 성장시킬 수 있어 산란효과의 극대화 및 전극의 표면적을 넓히는 장점이 있다. 각각의 방법을 이용하여 만든 구조 위에 입자 크기 10 nm의 $TiO_2$를 Dr blade 방법으로 도포하여 double layer (산란층+흡수층)로 구성된 작업 전극을 이용한 DSSCs를 제작한 후 I-V curve와 EIS (Electrochemical Impedance Spectroscopy)를 측정하여 효율 및 전기화학적 특성을 분석하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.336-337
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• 2007

The energy conversion characteristics of $TiO_2$ paste of dye-sensitized solar cell (DSSC) was investigated. In the case of DSSC without a binder, the current density increased due to the development of porosity. As for DSSC with a binder, the fill factor increased due to the development of network among the particles. The energy conversion efficiency of 7.2% was obtained due to the porosity and the network as for DSSC with the mixed binder (Vol. 50:50).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.4
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• pp.66-72
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• 2010

In this paper, AZO thin film was deposited on polyethylene terephthalate(PET) substrate by r. f. magnetron sputtering method from a ZnO target mixed with 2[wt%] Al2O3. The flexible film-typed dye sensitized solar cell(F-DSC) was fabricated and photo-electric conversion efficiency was investigated. The results showed that the minimum resistivity and the maximum deposition rate of AZO conducting film were recorded as $1.8{\times}10^{-3}[{\Omega}{\cdot}cm]$ and 25.5[nm/min], respectively at r.f. power of 220[W]. From the analysis of XPS data an improvement of electrical resistivity or an increase in carrier concentration with increasing sputtering power may be related to the generation of lattice imperfections as a result of increasing component ratio of O1s/Zn2p, which generates donor carriers or active growth of crystalline grain. The photo-electric conversion efficiency of F-DSC with AZO conducting electrode was over 2.79[%], which was comparable as that with commercially available ITO electrode.