• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1090-1094
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• 2004

Studies on porous oxide electrode, dye and electrolyte for dye-sensitized solar cells have been intensively carried out until now. However, counter electrode have not been much studied so far. Accordingly, it is needed to investigate new counter electrode materials with superior catalyst property and to substitute for Pt electrode. In this case, carbon nano-tubes (CNTs) are one of alternatives for counter electrodes as following merits: low resistivity, excellent electron emission property, large surface area and low cost due to development of mass production technique. Such advantages gave us to select multiwalled CNTs (MWCNT) as counter electrode for dye-sensitized solar cell. Also, cyclic voltammetry and impedance spectroscopy were used to investigate electrochemical properties of both CNT electrode and Pt electrode. It was found that sheet resistance of CNT electrode was similar to that of Pt electrode, also, electrochemical properties of CNT electrode was superior to that of Pt electrode on the basis on the measurement of CV and impedance spectrum. It was found that CNT is likely to be a very promising electrode material for dye solar cells.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.147-148
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• 2007

Dye-sensitized solar cell using conversion of solar energy to electrical energy appeared that which solves a environmental matter. The dye-sensitized solar cell uses nano-crystalline oxide semiconductor for absorbing dye. The $TiO_2$ is used most plentifully. The efficiency of the dye-sensitized solar cell changes consequently in the particle size, morphology, crystallization and surface state of the $TiO_2$. In this paper, we report The effect of titania$(TiO_2)$ thickness on the performance of dye-sensitized solar cells. Using doctor blade method, It produced the thickness of the $TiO_2$ with $7\;{\mu}m,\;10\;{\mu}m,\;13\;{\mu}m$. The efficiency was the best from $10{\mu}m$. It had relatively low efficiency on the thickness from $7\;{\mu}m\;to\;13\;{\mu}m$. The reason why it presents low efficiency on $7\;{\mu}m$ thickness is that excited electrons can not be delivered enough due to thin thickness of $7\;{\mu}m\;TiO_2$. And The reason why it presents low efficiency on $13\;{\mu}m$ thickness is that thick $13\;{\mu}m\;TiO_2$ can not penetrate the sunlight enough.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.354-355
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• 2006

We manufactured photoelectrode of dye-sensitized solar cells (DSC) by using three methods such as squeeze method, spray method, and combination method (squeeze method first, spray method second). We examined how the morphology of an electrode's surface, the pore between particles, and condensation have an effect on an open-circuit voltage, photocurrent, fill factor, and energy conversion efficiency. Open-circuit voltage of dye-sensitized solar cells manufactured by using three methods is about 0.66V when the photoelectrode of the three DSCs is about $5{\mu}m$ thick. Photocurrent and fill factor and conversion efficiency of DSC manufactured by using squeeze method is 18.5 and 34 and 7.8, respectively. Photocurrent and fill factor and conversion efficiency of DSC manufactured by using spray method is 3.62 and 62 and 2.8, respectively. Photocurrent and fill factor and conversion efficiency of DSC manufactured by using combination method is 10.7 and 46 and 5.9, respectively. In conclusion, we find that the combination method is better than the other two methods in such respects as energy conversion efficiency and fill factor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.3
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• pp.175-179
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• 2015

In this study, we propose Ti hole pattern structure on the transparent conductive oxide (TCO) less dye-sensitized solar cells (DSSCs) using the lift-off process to improve the low light transmittance and low efficiency caused by opaque Ti electrode. The formation of Ti hole patterns make it possible to move the dye adsorption and electrolyte. The DSSCs with Ti hole patterns showed a higher photoelectric conversion efficiency (PCE) than those with general structure by 11.1%. As a result, The Ti hole pattern structure can be improved to increase the light absorption of the dyes and PCE of the TCO-less DSSCs is also increased.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.483.2-483.2
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• 2014

In this study, we describe a simple selective etching method that produces noncurling, freestanding, large-area, aligned $TiO_2$ nanotube (NT) with doubly ends opened. The novel selective etching process only removed the thin 2nd bottom layer from the physically and chemically stable thick amorphous 1st top layer under thermal treatment at $250^{\circ}C$, yielding ordered doubly open-ended NT (DNT) that could be easily transferred to an FTO substrate for the fabrication of front-illuminated dye sensitized solar cells (DSCs). The DNT-DSCs yielded a higher PCE (8.6%) than was observed from $TiO_2$ nanoparticle (TNP)-based DSCs (7.3%), for comparable film thicknesses of $16{\mu}m$, despite of 20% decreased amount of dye. Intensity-modulated photocurrent and photovoltage spectroscopy (IMPS and IMVS, respectively) revealed that the DNT-DSCs exhibited electron lifetimes that were 10 times longer than those of TNP-DSCs, which contributed to high device performances.

• Transactions on Electrical and Electronic Materials
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• v.14 no.2
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• pp.86-89
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• 2013

Dye-sensitized solar cells have a FTO/$TiO_2$/Dye/Electrode/Pt counter electrode structure, yet more than a 10% electron loss occurs at each interface. A passivating layer between the $TiO_2$/FTO glass interface can prevent this loss of electrons. In theory, ZnO has excellent electron collecting capabilities and a 3.4 eV band gap, which suppresses electron mobility. FTO glass was coated with ZnO thin films by RF-magnetron sputtering; each film was deposited under different $O_2$:Ar ratios and RF-gun power. The optical transmittance of the ZnO thin film depends on the thickness and morphology of ZnO. The conversion efficiency was measured with the maximum value of 5.22% at an Ar:$O_2$ ratio of 1:1 and RF-gun power of 80 W, due to effective prevention of the electron recombination into electrolytes.

• Journal of Electrochemical Science and Technology
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• v.10 no.2
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• pp.214-222
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• 2019

Dye-sensitized solar cells (DSSCs) have been receiving growing attentions as a potential alternative to order photovoltaic devices due to their high efficiency and low manufacturing cost. DSSCs are composed of a photosensitizing dye adsorbed on a mesoporous film of nanocrystalline $TiO_2$ as a photoelectrode, an electrolyte containing triiodide/iodide redox couple, and a platinized counter electrode. To improve photovoltaic properties of DSSCs, new dicationic salts based on ionic liquids were synthesized. Quite comparable efficiencies were obtained from electrolytes with new dicationic iodide salts. The best cell performance of 7.96% was obtained with dicationic salt of PBDMIDI.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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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.

• Current Photovoltaic Research
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• v.4 no.2
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• pp.42-47
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• 2016

Increasing the efficiency of dye-sensitized solar cells (DSSCs) by the fabrication of new photoelectrodes (PEs) is an important challenge. This study examined the photovoltaic parameters of DSSCs composed of a $TiO_2$ PE with $WO_3$ nanoparticles (NPs). A number of PEs with the same thickness but different concentrations of $WO_3$ NPs in the $TiO_2PE$ were prepared. The morphology and structural properties of the prepared PEs were examined by field-emission scanning electron microscopy and X-ray diffraction, respectively. The effects of the $WO_3$ NPs mixing concentration on the efficiency of DSSCs were investigated under simulated solar light irradiation.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4382-4386
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• 2011

$TiO_2$ hollow spheres were fabricated by using $SiO_2$ as an inorganic template. Spherical $SiO_2$ particles were coated by $TiO_2$ through the nucleation process, and then the core $SiO_2$ part was eliminated by using HF solution. Finally, $TiO_2$ hollow spheres were obtained. The size of the $TiO_2$ hollow spheres was about 300-400 nm and the thickness of the hollow wall was about 20-30 nm. The hollow has several holes whose diameters were within 100-200 nm. Dye-sensitized solar cells fabricated by using the $TiO_2$ hollow spheres were characterized. The solar conversion efficiency of the cell was 8.45% when $TiO_2$ hollow spheres were used as a scattering material, while it was 4.59% when $TiO_2$ hollow spheres were used as a normal electrode material.