• Bulletin of the Korean Chemical Society
• /
• v.34 no.3
• /
• pp.831-836
• /
• 2013

Platinized counter electrode is common in most of the dye sensitized solar cell (DSSC) researches because of its high catalytic activity and corrosion stability against iodine in the electrolyte. Platinum (Pt) film coating on fluorine doped tin oxide (FTO) glass surface by using alcoholic solution of hexachloroplatinic acid ($H_2PtCl_6$), paste containing Pt precursors or sputtering are widely used techniques. This paper presents a novel application of Pt ink containing nanoparticles for making platinized counter electrode for DSSC. The characteristics of Pt films coated on FTO glass surface by different chemical methods were compared along with the performance parameters of the DSSCs made by using the films as counter electrodes. The samples coated with Pt inks were sintered at $300^{\circ}C$ for 30 minutes whereas Pt-film and Pt-paste were sintered at $400^{\circ}C$ for 30 minutes. The Pt ink diluted in n-hexane was found to a promising candidate for the preparation of platinized counter electrode. The ink may also be applicable for DSSC on flexible substrates after optimization its sintering temperature.

• Advances in nano research
• /
• v.2 no.1
• /
• pp.23-56
• /
• 2014

The significant growth of the Si photovoltaic industry has been so far limited due to the high cost of the Si photovoltaic system. In this regard, the most expensive factors are the intrinsic cost of silicon material and the Si solar cell fabrication processes. Conventional Si solar cells have p-n junctions inside for an efficient extraction of light-generated charge carriers. However, the p-n junction is normally formed through very expensive processes requiring very high temperature (${\sim}1000^{\circ}C$). Therefore, several systems are currently under study to form heterojunctions at low temperatures. Among them, carbon nanotube (CNT)/Si hybrid solar cells are very promising, with power conversion efficiency up to 15%. In these cells, the p-type Si layer is replaced by a semitransparent CNT film deposited at room temperature on the n-doped Si wafer, thus giving rise to an overall reduction of the total Si thickness and to the fabrication of a device with cheaper methods at low temperatures. In particular, the CNT film coating the Si wafer acts as a conductive electrode for charge carrier collection and establishes a built-in voltage for separating photocarriers. Moreover, due to the CNT film optical semitransparency, most of the incoming light is absorbed in Si; thus the efficiency of the CNT/Si device is in principle comparable to that of a conventional Si one. In this paper an overview of several factors at the basis of this device operation and of the suggested improvements to its architecture is given. In addition, still open physical/technological issues are also addressed.

• Journal of Electrochemical Science and Technology
• /
• v.2 no.2
• /
• pp.68-75
• /
• 2011

In this review, we have investigated the effect of $TiO_2$-based blocking layers (t-BLs), deposited on a transparent conductive oxide (TCO)-coated glass substrate, on the photovoltaic performance of dye-sensitized solar cells (DSSCs). The t-BL was deposited using spin-coating or sputtering technique, and its thicknesses were varied to study the influence of the thin $TiO_2$ layer in between transparent conducting glass and nanocrystalline $TiO_2$ (nc-$TiO_2$). The DSSC with the t-BL showed the improved adhesion and the suppressed charge recombination at a TCO glass substrate than those without the t-BL, which led to the higher conversion efficiency.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.3
• /
• pp.180-184
• /
• 2015

Stainless steel (SS) mesh was used to fabricate photoelectrode for flexible dye-seisitzed solar cells (DSSCs) in order to evaluate them as replacements for more expensive transparent conductive oxide(TCO). We fabricated the DSSCs with new type of photoelectrode, which consisted of flexible SS mesh coated with 100 nm thickness titanium (Ti) protective layer deposited using electron-beam deposition system. SS mesh DSSCs with protective layer showed higher efficiency than those without a protective layer. The best cell property in the present study showed the open circuit voltage (Voc) of 0.608 V, short-circuit current density (Jsc) of $5.73mA\;cm^{-2}$, fill factor (FF) of 65.13%, and efficiency (${\eta}$) of 2.44%. Compared with SS mesh based on DSSCs (1.66%), solar conversion of SS mesh based on DSSCs with protective layer improved about 47%.

• Clean Technology
• /
• v.23 no.3
• /
• pp.314-324
• /
• 2017

To verify the viability of Co, Ru and Zr-based catalyst for $CO_2$ (dry) reforming reaction, catalysts were fabricated using cordierite, silicon carbide and rota monolithic substrates, and they were compared with the conventional $Co-Ru-Zr/SiO_2$ catalyst in terms of performance and durability. Cordierite monolith was showed high activity with the least amount of active component. In addition, when Cordierite monolith was coated with Co-Ru-Zr in various ways, most excellent performance was showed at a precursor solution coating method. In particular, when 0.9 wt% Co-Ru-Zr/Cordierite was used for reaction, it was observed that 95% $CO_2$ conversion was maintained for 300 h at $900^{\circ}C$.

• 한국태양에너지학회:학술대회논문집
• /
• 2012.03a
• /
• pp.260-266
• /
• 2012

Syngas and hydrogen from the $CeO_2/ZrO_2$ coated foam devices were investigated under simulated solar radiation. The $CeO_2/ZrO_2$ coated SiC, Ni and Cu foam device were prepared using drop-coating method. Syngas production step was performed at $900^{\circ}C$, and hydrogen production process was performed for ten repeated cycles to compare the CeO2 conversion in syngas production step, $H_2$ yield in hydrogen production step and cycle reproducibility. The produced syngas had the $H_2$/CO ratio of 2, which was suitable for methanol synthesis or Fischer-Tropsch synthesis process. In addition, syngas and hydrogen production process is one of the promising chemical pathway for storage and transportation of solar heat by converting solar energy to chemical energy. After ten cycles of redox reaction, the $CeO_2/ZrO_2$ was analyzed using XRD pattern and SEM image in order to characterize the physical and chemical change of metal oxide at the high temperature.

• Journal of Adhesion and Interface
• /
• v.14 no.4
• /
• pp.167-174
• /
• 2013

In this study, Ultraviolet (UV) curable urethane acrylates for ink binder was prepared by reaction of IPDI, polyether polyol and HEA. The UV curing behavior of compositions with HEA/PETA ratio on UV irradiation time was investigated by FT-IR spectrophotometer, probe tack tester and Photo-DSC. Conversion % and gel content were increased with increasing UV irradiation time, but probe tack was decreased. Storage modulus, tensile strength and decomposition temperature were increased as PETA content increased. In case of HEA/PETA ratio was 30/70, adhesion property of UV-cured composition on PMMA sheet was excellent.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2017.05a
• /
• pp.148-148
• /
• 2017

Surface modification is a type of mechanical manipulation skills to achieve extensive aims including corrosion control, exterior appearance, abrasion resistance, electrical insulation and electrical conductivity of substrate materials by generating a protective surface using electrical, physical and chemical treatment on the surface of parts made from metallic materials. Such surface modification includes plating, anodizing, chemical conversion treatment, painting, lining, coating and surface hardening; this study conducted cavitation experiment to assess improvement of durability using anodizing. In order to observe surface characteristics with applied current density, the electrolyte temperature, concentration was maintained at constant condition. To prevent hindrance of stable growth of oxide layer due to local temperature increase during the experiment, stirring was maintained at constant speed. In addition, using galvanostatic method, it was maintained at processing time of 40minutes for 10 to $30mA/cm^2$. The cavitation experiment was carried out with an ultra sonic vibratory apparatus using piezo-electric effect with modified ASTM-G32. The peak-to-peak amplitude was $30{\mu}m$ and the distance between the horn tip and specimen was 1mm. The specimen after the experiment was cleaned in an ultrasonic bath, dried in a vacuum oven for more than 24 hours, and weighed with an electric balance. The surface damage morphology was observed with 3D analysis microscope. As a result of the study, differences were observed surface hardness and anti-cavitation characteristics depending on the development of oxide film with the anodizing process time.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.376-376
• /
• 2011

I-III-VI2 chalcopyrite compounds, particularly copper, indium, gallium selenide(Cu(InxGa1-x)Se2, CIGS), are effective light-absorbing materials in thin-film solar application. They are direct band-gap semiconductors with correspondingly high optical absorption coefficients. Also they are stable under long-term excitation. CIS (CIGS) solar cell reached conversion efficiencies as high as 19.5%. Several methods to prepare CIS (CIGS) absorber films have been reported, such as co-evaporation, sputtering, selenization, and electrodeposition. Until now, co-evaporation is the most successful technique for the preparation of CIS (CIGS) in terms of solar efficiency, but it seems difficult to scale up. CIS solar cells have been hindered by high costs associated with a fabrication process. Therefore, inorganic colloidal ink suitable for a scalable coating process could be a key step in the development of low-cost solar cells. Here, we will present the preparation of CIS photo absorption layer by a solution process using novel metal precursors. Chalcopyrite copper indium diselenide (CuInSe2) nanocrystals ranging from 5 to 20nm in diameter were synthesized by arrested precipitation in solution. For the fabrication of CIS photo absorption layer, the CuInSe2 colloidal ink was prepared by dispersing in organic solvent and used to drop-casting on molybdenum substrate. We have characterized the nanoparticless and CIS layer by XRD, SEM, TEM, and ICP.

• Journal of Powder Materials
• /
• v.8 no.3
• /
• pp.201-206
• /
• 2001

$>LaMnO_3$$(La, Sr)MO_3$, and $(La, Sr)MO_3/YSZ$ gel films were deposited by spin-coating technique on scandium-doped zirconia (YSZ) substrate using the precursor solution prepared from $La(O-i-C_3H_7)_3$, $Co(CH_3COO)_2$or $Mn(O-i-C_3H_7)_2$,2-methoxyethanol, and polyethylene glycol. By heat-treating the gel films, the electrochemical cells, $(La, Sr)MnO_3{\mid}ScSZ{\mid}Pt$ were fabricated. The effect of polyethylene glycol on the microstructure evolution of $$LaCoO_3and $LaMnO_3$thin films was investigated, and NOx decomposition characteristics of the electrochemical cells were investigated at $500^{\circ}C$ to $600^{\circ}C$. By applying a direct current to the $(La, Sr)MnO_3{\mid}ScSZ{\mid}Pt$ electrochemical cell, good NOx conversion rate could be obtained relatively at low current value even if excess oxygen is included in the reaction gas mixture.