• Membrane Journal
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• v.21 no.2
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• pp.193-200
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• 2011

An amphiphilic graft copolymer comprising a poly(vinyl chloride) (PVC) backbone and poly (styrene sulfonic acid) (PSSA) side chains (PVC-g-PSSA) was synthesized via atom transfer radical polymerization (ATRP). Mesoporous titanium dioxide $(TiO_2)$ films with crystalline anatase phase were synthesized via a sol-gel process by templating PVC-g-PSSA graft copolymer. Titanium isopropoxide (TTIP), a $TiO_2$ precursor was selectively incorporated into the hydrophilic PSSA domains of the graft copolymer and grew to form mesoporous $TiO_2$ films, as confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The performances of dye-sensitized solar cell (DSSC) were systematically investigated by varying spin coating times and the amounts of P25 nanoparticies. The energy conversion efficiency reached up to 2.7% at 100 mW/$cm^2$ upon using quasi-solid-state polymer electrolyte.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.177-181
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• 2012

Dye-sensitized solar cells(DSSCs) based on $TiO_2$ film photo anode incorporated with different amount of grapheme nanosheet(GNS) are fabricated and their photovoltaic performance are investigated. The $TiO_2$-GNS composite electrode has been prepared by a direct mixing method. The DSSC performance of this composite electrode was measured using N3 dye as a sensitizer. The performance of DSSCs using the $TiO_2$-GNS composite electrodes is dependent on the GNS loading in the electrodes. The results show that the DSSCs incorporating 0.01 wt% GNS in $TiO_2$photo anode demonstrates a maximum power conversion efficiency of 5.73%, 26% higher than that without GNS. The performance improvement is ascribed to increased N3 dye adsorption, the reduction of electron recombination and back transport reaction as well as enhancement of electron transport with the introduction of GNS. The presence of both $TiO_2$(anatase) and GNS has been confirmed by FieldEmission Scanning Electron Microscopy(FE-SEM). The decrease in recombination due to GNS in DSSCs has been investigated by the Electrochemical Impedance Spectroscopy.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.92-97
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• 2009

It is more necessary to consider the various factors for developmenting visible PV module of alternative window than traditional PV module. It must have sufficient performance which is Tvis, daylighting, daylight factor, glare index. so that more needs to consider suitable plan and total evaluated technology. Under the this background. For using commonly a combination BIPV module system and Daylinghting that can alternative architectural window, our goal on this study is drawing proper window area ratio as the window by analyzing lighting performance and glare index depending on transmittance of DSSC. On this study, we drew the result about window area ratio that can apply in the building when applying DSSC in the window. In situation that window is alternated as curtain wall in atrium that has big Widow area, if applying red 15.8% DSSC of low transmittance, it is expect to proper because it is suitable illumination standard and doesn't occur a discomfort glare. In case of office, we propose to apply red 33.2% or blue 35.2% DSSC of high transmittance for no affecting lighting load. we expect to contribute to select proper and effective window when applying the window in the building by drawing the window area ratio that can apply in thee building depending on transmittance of DSSC and offering the glare index data.

• Membrane Journal
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• v.20 no.1
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• pp.13-20
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• 2010

Using poly(ethylene oxide) (PEO) as a polymer host, poly(ethylene glycol) (PEG) as a plasticizer, potassium iodide and iodine as sources of $I^-/{I_3}^-$ PEO-PEG-KI/$I_2$ polymer gel electrolytes were prepared. Based on the polymer gel electrolytes, solid-state dye-sensitized solar cell(DSSC)s were fabricated. The content of PEG in the electrolyte was changed from 0 to 85%. The electrolyte showed self-supporting form through whole range of the PEG content. As the PEG content increased, the ionic conductivity and ${I_3}^-$ diffusivity increased and the light-to electrical energy conversion efficiency increased under irradiation of 100 $mWcm^{-2}$ simulated sunlight.

• Analytical Science and Technology
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• v.27 no.6
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• pp.308-313
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• 2014

The effect of electrochemical characteristics of dye-sensitized solar cells (DSSC) upon employing multi-wall carbon nanotube (MWCNT) on both working electrode and counter electrode were examined with using EIS, J-V curves and UV-Vis absorption spectrometry. When 0.1 wt% of MWCNT was employed in the $TiO_2$-MWCNT composit on working electrode, the energy conversion efficiency increased about 12.5% compared to the $TiO_2$ only working electrode. The higher light conversion efficiency may attribut to the high electrical conductivity of MWCNT in $TiO_2$-MWCNT composite which improves the electron transport in the working electrode. However, higher amount of MWCNT than 0.1 wt% in the $TiO_2$-MWCNT composite decreases the light conversion efficiency, which is mainly ascribed to the decreased transmittance of light by MWCNT and to the decreased adsorption of dye onto $TiO_2$. The MWCNT employed counter electrode exhibited much lower light conversion efficiency of DSSC than the Pt-counter electrode, while the MWCNT-Pt counter electrode showed similar in light conversion efficiency to that of Pt-counter electrode.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.75-75
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• 2011

Recently, dye-sensitized solar cell (DSSC) attracts great attention as a promising alternative to conventional silicon solar cells. One of the key components for the DSSC would be the nanocrystalline TiO2 electrode, and the control of interface between TiO2 and TCO is a highly important issue in improving the photovoltaic conversion efficiency. In this work, we applied various interfacial layers, and analyzed their effect in enhancing photovoltaic properties. In overall, introduction of interfacial layers increased both the Voc and Jsc, since the back-reaction of electrons from TCO to electrolyte could be blocked. First, several metal oxides with different band gaps and positions were employed as interfacial layer. SnO2, TiO2, and ZrO2 nanoparticles in the size of 3-5 nm have been synthesized. Among them, the interfacial layer of SnO2, which has lower flat-band potential than that of TiO2, exhibited the best performance in increasing the photovoltaic efficiency of DSSC. Second, long-range ordered cubic mesoporous TiO2 films, prepared by using triblock copolymer-templated sol-gel method via evaporation-induced self-assembly (EISA) process, were utilized as an interfacial layer. Mesoporous TiO2 films seem to be one of the best interfacial layers, due to their additional effect, improving the adhesion to TCO and showing an anti-reflective effect. Third, we handled the issues related to the optimum thickness of interfacial layers. It was also found that in fabricating DSSC at low temperature, the role of interfacial layer turned out to be a lot more important. The self-assembled interfacial layer fabricated at room temperature leads to the efficient transport of photo-injected electrons from TiO2 to TCO, as well as blocking the back-reaction from TCO to I3-. As a result, fill factor (FF) was remarkably increased, as well as increase in Voc and Jsc.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.316-316
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• 2010

Six metal-free organic dyes having thiophene (1), benzene-thiophene (2), thiophene-benzene (3), thiophene-pyridine(4), thiophene-thiophene (5), and pyridine (6) linkers between 9,9-dimethylfluorenyl terminal group and $\alpha$-cyanoacrylic acid anchor were synthesized. Among them, organic dye 5 showed the longest ${\lambda}}max$ value (424 nm) in UV-Vis absorption spectrum, better incident monochromatic photon-to-current conversion efficiency (IPCE), highest short circuit photocurrent density (JSC, 9.33 mA2/cm2), and highest overall conversion efficiency ($\eta$, 3.91%).

• Korean Journal of Materials Research
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• v.27 no.2
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• pp.94-99
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• 2017

Dinickel-silicide $(Ni_2Si)/glass$ was employed as a counter electrode for a dye-sensitized solar cell (DSSC) device. $Ni_2Si$ was formed by rapid thermal annealing (RTA) at $700^{\circ}C$ for 15 seconds of a 50 nm-Ni/50 nm-Si/glass structure. For comparison, $Ni_2Si$ on quartz was also prepared through conventional electric furnace annealing (CEA) at $800^{\circ}C$ for 30 minutes. XRD, XPS, and EDS line scanning of TEM were used to confirm the formation of $Ni_2Si$. TEM and CV were employed to confirm the microstructure and catalytic activity. Photovoltaic properties were examined using a solar simulator and potentiostat. XRD, XPS, and EDS line scanning results showed that both CEA and RTA successfully led to tne formation of nano $thick-Ni_2Si$ phase. The catalytic activity of $CEA-Ni_2Si$ and $RTA-Ni_2Si$ with respect to Pt were 68 % and 56 %. Energy conversion efficiencies (ECEs) of DSSCs with $CEA-Ni_2Si$ and $RTA-Ni_2Si$catalysts were 3.66 % and 3.16 %, respectively. Our results imply that nano-thick $Ni_2Si$ may be used to replace Pt as a reduction catalytic layer for a DSSCs. Moreover, we show that nano-thick $Ni_2Si$ can be made available on a low-cost glass substrate via the RTA process.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.1
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• pp.48-57
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• 2013

This paper presents a power management system of the dye-sensitized solar cell (DSSC) for ubiquitous sensor network (USN) applications. The charge pump with a luminance-controlled oscillator regulates the load impedance of the DSSC to track the maximum power point (MPP) under various light intensities. The low drop-out regulator with a hysteresis comparator supplies intermittent power pulses that are wide enough for USN to communicate with a host transponder even under dim light conditions. With MPP tracking, approximately 50% more power is harvested over a wide range of light intensity. The power management system fabricated using $0.13{\mu}m$ CMOS technology works with DSSC to provide power pulses of $36{\mu}A$. The duration of pulses is almost constant around $80{\mu}s$ (6.5 nJ/pulse), while the pulse spacing is inversely proportional to the light intensity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.1-7
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• 2017

Cobalt silicide was used as a counter electrode in order to confirm its reliability in dye-sensitized solar cell (DSSC) devices. 100 nm-Co/300 nm-Si/quartz was formed by an evaporator and cobalt silicide was formed by vacuum heat treatment at $700^{\circ}C$ for 60 min to form approximately 350 nm-CoSi. This process was followed by etching in $80^{\circ}C$-30% $H_2SO_4$ to remove the cobalt residue on the cobalt silicide surface. Also, for the comparison against Pt, we prepared a 100 nm-Pt/glass counter electrode. Cobalt silicide was used for the counter electrode in order to confirm its reliability in DSSC devices and maintained for 0, 168, 336, 504, 672, and 840 hours at $80^{\circ}C$. The photovoltaic properties of the DSSCs employing cobalt silicide were confirmed by using a simulator and potentiostat. Cyclic-voltammetry, field emission scanning electron microscopy, focused ion beam scanning electron microscopy, and energy dispersive spectrometry analyses were used to confirm the catalytic activity, microstructure, and composition, respectively. The energy conversion efficiency (ECE) as a function of time and ECE of the DSSC with Pt and CoSi counter electrodes were maintained for 504 hours. However, after 672 hours, the ECEs decreased to a half of their initial values. The results of the catalytic activity analysis showed that the catalytic activities of the Pt and CoSi counter electrodes decreased to 64% and 57% of their initial values, respectively(after 840 hours). The microstructure analysis showed that the CoSi layer improved the durability in the electrolyte, but because the stress concentrates on the contact surface between the lower quartz substrate and the CoSi layer, cracks are formed locally and flaking occurs. Thus, deterioration occurs due to the residual stress built up during the silicidation of the CoSi counter electrode, so it is necessary to take measures against these residual stresses, in order to ensure the reliability of the electrode.