• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.68.2-68.2
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• 2010

Dye-sensitized solar cells (DSSC) show great promise as an inexpensive alternative to conventional p-n junction solar cells. Investigations into the various factors influencing the photovoltaic efficiency have recently been intensified. The conventional absorber electrode in DSSC is composed of compacted or sintered $TiO_2$ nanopowder that carries an anchored organic dye. The absorbance of incident light in the DSC is realized by specifically engineered dye molecules placed on the semiconductor electrode surface ($TiO_2$). The dye absorbs light at wavelengths up to about 920nm, the energy of the exited state of the molecule should be about 1.35eV above the electronic ground state corresponding to the ideal band gap of a single band gap solar cell. The dye molecules ar adhered onto the nanostrutured $TiO_2$ electrode by immersing the sintered electrode into a dye solution, typically 3mM in alcohol, for a long enough period to fully impregnate the electrode. However, the concentrations of the dye is slightly changed due to the evaporation of the alcohol. The dye is more expensive than other materials in DSSC and related to the efficiency of DSSC. Therefore, the concentrations of the dye should be carefully measured. In this study, we investigated to the dye loading on fired $TiO_2$ powder as a function of temperature by the TG-DTA and the dye solution by UV-visible spectroscopy after the impregnation process. The dye loading is related to the porosity of the nanostructured $TiO_2$ electrode.

• Journal of Electrochemical Science and Technology
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• 제7권3호
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• pp.218-227
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• 2016

The light harvesting efficiency is counted as an important factor in the power conversion efficiency of DSSCs. There are two measures to improve this parameter, including enhancing the dye-loading capacity and increasing the light trapping in the photoanode structure. In this paper, these tasks are addressed by introducing a macro-porous silicon (PSi) substrate as photoanode. The effects of the novel photoanode structure on the DSSC performance have been investigated by using energy dispersive X-ray spectroscopy, photocurrent-voltage, UV-visible spectroscopy, reflectance spectroscopy, and electrochemical impedance spectroscopy measurements. The results indicated that bigger porosity percentage of the PSi structure improved the both anti-reflective/light-trapping and dye-loading capacity properties. PSi based DSSCs own higher power conversion efficiency due to its remarkable higher photocurrent, open circuit voltage, and fill factor. Percent porosity of 64%, PSi(III), resulted in nearly 50 percent increment in power conversion efficiency compared with conventional DSSC. This paper showed that PSi can be a good candidate for the improvement of light harvesting efficiency in DSSCs. Furthermore, this study can be considered a valuable reference for more investigations in the design of multifunctional devices which will profit from integrated on-chip solar power.

• 한국염색가공학회지
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• 제11권2호
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• pp.19-26
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• 1999

Strains degrading and decolorizing acid dyes, Nylosan red E-BL 150%. were isolated from natural system, was named as ARK3. The optimal culture conditions of temperature and pH were $35^\circ{C}$, 7.0, respectively. Growth rate of cells in conditions of aerobic shaking more than standing culture conspicuously increased, and optical density of those to strain ARK3 were found as 1.38 and 0.25 after 42 hrs. Decolorization efficiency in batch culture which used as immobilization media to natural zeolite was 15% after 6 hrs, while suspension culture was 5%, also its of immobilization and suspension culture were 90% and 85% after 48 hrs, respectively. Decolorization efficiency of air-lift bioreactor was more than 90% to a dilution rate of $0.038hr^{-1}$, but that was decreased as 70%, when the dilution rate was $0.05hr^{-1}$. Even though at maximum dilution rate of this study, there was not appeared "wash out" phenomienon of biomass. Decolorization efficiency was 97.7% at a dilution rate of $0.025hr^{-1}$, when influent dye concentration was $100mg/\ell$. But if influent dye concentration increased as $150mg/\ell$, even though MLVSS increased, that of treatment water decreased as 93%. Also, when influent dye concentration increased as $200mg/\ell$ and $300mg/\ell$, decolorization efficiencies of treatment water abruptly decreased as 85% and 63%, respectively. Decolorization efficiency was more than 92% to the limit volumetric loading rate of $3.75mg/\ell\cdot{hr}$hr, without regard to variation of influent dye concentration or hydraulic retention time. if volumetric loading rate was more than $3.80mg/\ell\cdot{hr}$, at same condition, decolorization efficiency was lower decrease of retention time than increase of influent dye concentration.entration.

• 한국환경과학회지
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• 제11권6호
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• pp.569-576
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• 2002

Anaerobic/aerobic reactor system was used to treat a synthetic wastewater with glucose as carbon sources(0.38~2.29 kg COD/m3.day) and Acid Red 14(1.05 "24.00 g Acid Red 141m3.day, color degree of 570 ~ 1710). COD removal efficiency by the anaerobic stage in operation period were above 90 % organic loading rate of 0.38 ~ 2.29 kg COD/m3.day(except, adaptation period) and the removal efficiency of the whole system were above 96 %. The decolorization of the Acid Red 14 was through the alteration of the dye structure(or cleavage of the Azo bond) during the anaerobic treatment. In the A/A system, the anaerobic stage played an essential role in removing both color and COD. In addition it also improves biodegradability of dye f3r further aerobic treatment. After operation, average MLSS concentration of anaerobic sludge reactor, anaerobic fixed-bed reactor and aerobic fixed-bed reactor were 17100mg/L, 20000mg/L, and 10000mg/L, respectively.

• 상하수도학회지
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• 제23권4호
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• pp.431-438
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• 2009

The purpose of this study was to evaluate the performances of zero-valent iron (ZVI) combined SBR (Z-SBR) process in decolorization and organic removal of synthetic dye wastewater. The batch test for optimizing the operation parameters of ZVI column showed that the appropriate EBCT was around 11 min and the pH of the dye wastewater was below 7.0. During the step increase of influent color unit from 300 to 1,000cu, about 53 to 79% decolorization efficiency could be achieved in control SBR (C-SBR, without ZVI column), which resulted from destroying azo bond of synthetic dye in anaerobic condition. For the same influent color loading, Z-SBR showed always higher decolorization efficiency than C-SBR with an aid of ZVI reducing power. The TCOD concentration in Z-SBR effluent was 20-30mg/L lower than C-SBR effluent although the TCOD before and after ZVI column was nearly same. It means that breakdown of azo bond by ZVI reducing power could increase biodegradability of synthetic dye wastewater.

• 한국전기전자재료학회논문지
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• 제25권2호
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• pp.153-158
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• 2012

We use UV(ultraviolet)-$O_3$ treatment to increase the surface area and porosity of $TiO_2$ films in dye-sensitized solar cells (DSSCs). After the UV-$O_3$ treatment, surface area and porosity of the $TiO_2$ films were increased, the increased porosity lead to amount of dye loading and solar conversion efficiency was improved. Field emission scanning electron microscopy images clearly showed that the nanocrystalline porosity of films were increased by UV-$O_3$ treatment. The Brunauer, Emmett, and Teller surface area of the $TiO_2$ films were increased from $0.71cm^2/g$ to $1.31cm^2/g$ by using UV-$O_3$ treatment for 20 min. Also, UV-$O_3$ treatment of $TiO_2$ films significantly enhanced their solar conversion efficiency. The efficiency of the films without treatment was 4.9%, and was increased to 5.6% by UV-$O_3$ treatment for 20 min. Therefore the process enhanced the solar conversion efficiency of DSSCs, and can be used to develop high sensitivity DSSCs.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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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 Ginseng Research
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• 제30권2호
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• pp.64-69
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• 2006

Gap junctional channels, allowing rapid intercellular communication and synchronization of coupled cell activities, play crucial roles in many signaling processes, including a variety of cell activities. Consequently, a modulation of the gap junctional intercellular communication (GJIC) should be a potential pharmacological target. In the present, the GJIC of a epithelial-derived rat mammary cells (BICR-M1Rk) was assessed in the presence of ginseng saponin, by using an established method of scrape-loading dye transfer assay. The transfer of Lucifer yellow (diameter: 1.2 nm) among the neighboring BICR-M1Rk cells, in which connexin43 (Cx43) is a major gap junction channel-forming protein, was significantly retarded at a concentration of $10{\mu}g/ml$ ginseng saponin. By using both methods of RT-PCR and Western blotting, it was demonstrated that ginseng saponin modulated neither the mRNA synthesis of Cx43 nor the translational process of Cx43. This ginseng saponin-induced modification of GJIC was a similar phenomenon observed under the $\beta$-glycyrrhetinic acid treatment, a well-known gap junction channel blocker. Taken together, it is reasonable to conclude that the ginseng saponin inhibits GJIC only by modulating the gating property of gap junction channels.

• Rapid Communication in Photoscience
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• 제3권1호
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• pp.16-19
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• 2014

Anodic self-organized titania nanotube (TNT) arrays have a great potential as efficient electron-transport materials for dye-sensitized solar cells (DSSC). Herewith we report the photovoltaic and kinetic investigations for a series of heteroleptic ruthenium complexes (RD16-RD18) sensitized on TNT films for DSSC applications. We found that the RD16 device had an enhanced short-circuit current density ($J_{SC}/mAcm^{-2}=15.0$) and an efficiency of power conversion (${\eta}=7.2%$) greater than that of a N719 device (${\eta}=7.1%$) due to the increasing light-harvesting and the broadened spectral features with thiophene-based ligands. However, the device made of RD17 (adding one more hexyl chain) showed smaller $J_{SC}(14.1mAcm^{-2})$ and poorer ${\eta}(6.8%)$ compare to those of RD16 due to smaller amount of dye-loading and less efficient electron injection for the RD17 device than for the RD16 device. For the RD18 dye (adding one more thiophene unit and one more hexyl chain), we found that the device showed even lower $J_{SC}(13.2mAcm^{-2}) $ that led to a poorest device performance (${\eta}=6.2%$) for the RD18 device. These results are against to those obtained from the same dyes sensitized on $TiO_2$ nanoparticle films and they can be rationalized according to the electron transport kinetics measured using the methods of charge extraction and transient photovoltage decays.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.670-674
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• 2012

The photovoltaic performance of solid-state dye-sensitized solar cells employing hole transport material (HTM), 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenyl-amine)-9,9'-spirobifluorene (spiro-MeOTAD), has been investigated in terms of HTM overlayer thickness. Two important parameters, soak time and spin-coating rate, are varied to control the HTM thickness. Decrease in the period of loading the spiro-MeOTAD solution on $TiO_2$ layer (soak time) leads to decrease in the HTM overlayer thickness, whereas decrease in spin-coating rate increases the HTM overlayer thickness. Photocurrent density and fill factor increase with decreasing the overlayer thickness, whereas open-circuit voltage remains almost unchanged. The improved photocurrent density is mainly ascribed to the enhanced charge transport rate, associated with the improved charge collection efficiency. Among the studied HTM overlayer thicknesses, ca. 230 nm-thick HTM overlayer demonstrates best efficiency of 4.5% at AM 1.5G one sun light intensity.