A novel process including electrodeposition at the low temperature of ca. 70 °C has been developed to prepare zinc oxide thin film with a micro-flower structure (MF-ZnO). Dye-sensitized solar cells (DSSCs) using the resulting MF-ZnO-electrode show high performance attributable to its improved electron diffusion coefficient and length. The cell had 14.12 mA/cm2 of short-circuit current, 0.694 V open-circuit voltage, a 0.61 fill factor, and 6.0 % conversion efficiency.
Inorganic nanoparticle films (TiO2, ITO, ZnO, Al2O3, and SiO2) were prepared using the micelle disruption method by which a nonionic surfactant with an azobenzen group (AZPEG) was reduced electrochemically. The surfactant, which adsorbed onto the inorganic nanoparticles to disperse them in aqueous solution, was desorbed from nanoparticles by electrolysis of the surfactant micelles. Particle films are formed if the nanoparticles had sufficient hydrophobicity to attach to the electrode. The inorganic nanoparticles were treated with silane-coupling agents to impart hydrophobicity, and silane-coupling agents of the type affected the particle film formation because the particle hydrophobicity was changed with the silane-coupling agents of the type. The AZPEG concentration in particle dispersions played an important role in forming particle films: optimal AZPEG concentration to form particle films was present. The optimal AZPEG concentration increased continuously with increasing specific surface area of the inorganic nanoparticles. After the nanoparticles had covered the electrode surface, nanoparticle film growth proceeded because AZPEG diffused through spaces in nanoparticle films. It was then reduced on the electrode.
In this study, a non-cyanide electropolishing solution was prepared for low-grade gold alloy containing palladium (Pd). Electropolishing conducted with an existing non-cyanide electropolishing solution prepared for 18-karat gold produced a rough and not mirror-finished 10-karat white gold (K10WG) surface. However, an electropolishing solution containing sodium sulfate and thiourea produced a smooth polished surface that exhibited some protrusions with a high Pd concentration. These protrusions decreased numerically when ethylene diamine tetraacetic acid tetrasodium (EDTA-4Na) was introduced into the sodium sulfate and thiourea solution to chelate noble metal such as Au and Pd. Electropolishing of K10WG using the solution containing thiourea, sodium sulfate, and EDTA-4Na produce a well-polished surface exhibiting high specular gloss.
Electroplating of nickel films was achieved by using foam electrolyte in place of the conventional liquid electrolyte. The Watt bath, to which was added 0.5 wt% of sulfuric acid monododecyl ester sodium salt (SDS), was bubbled with nitrogen gas to generate a stable foam electrolyte. Nickel films were electroplated on brass cathodes immersed in the foam. The cathodes were rotated in the foam to generate a flow of the foam on the surface during the electroplating process. The films deposited in the foam electrolyte showed higher corrosion resistance compared with films deposited in a liquid electrolyte. The corrosion resistance was improved at increasing cathode rotation speeds during the electroplating process.