| AVS 64th International Symposium & Exhibition | |
| Thin Films Division | Thursday Sessions |
| Session TF-ThP |
| Session: | Thin Films Poster Session |
| Presenter: | Taishi Segawa, Kogakuin University, Japan |
| Authors: | T. Segawa, Kogakuin University, Japan I. Takano, Kogakuin University, Japan |
| Correspondent: | Click to Email |
In recent years, titanium oxide has attracted attention for its various properties and has been studied in a wide application field such as solar cells or medical instruments. Particularly the photocatalytic effect of TiO2 produces antifouling, antibacterial action or decomposing environmental pollutants such as nitrogen oxide because the photocatalytic reaction of TiO2 generates the active species of superoxide anion or hydroxyl radical by using the energy of ultraviolet rays. One of the reasons why TiO2 is the superior material as a photocatalyst is that the photo-excited state is very stable and does not cause autolysis. Therefore TiO2 irradiated with ultraviolet rays can make the electrolysis of water stably proceed. On the other hand, the weak point of TiO2 is that the absorption wavelength is limited to the ultraviolet region under 380 nm. Therefore, many researchers have studied to improve the efficiency of the light reaction of TiO2. The distinctive point of our study is the energy supply of electricity during the light irradiation.
In this study, the glass substrates of 15×9 mm cleaned by an ultrasonic cleaner with acetone for 5 minutes were used. The TiO2/Ni films were prepared by the multi-process coating apparatus with magnetron sputtering sources. The TiO2 thin film preparation was carried out by sputtering a Ti target introducing an Ar and an O2 gas. An Ar gas and an O2 gas flow rate were set to 1.5 sccm and 20 sccm, respectively. The glass substrates were heated to 200 degrees by an infrared heater. The film thicknesses of TiO2 and Ni were changed with 0 - 100 nm to investigate the suitable condition.
The crystal structure of each thin film was analyzed by X-ray diffraction. Optical properties were measured using a UV-Visible spectrophotometer. The photocatalytic properties were measured by the methylene-blue immersion test under irradiation of the artificial sunlight (visible light) and the sterilizing lamp. The change of the methylene-blue transmittance was measured with a spectrophotometer at leaguer intervals.
In the case of the artificial sunlight irradiation, the methylene-blue transmittance of the TiO2/Ni (100/50 nm) film without the electric field application was 7 %, while that with the electric field application showed 45 %. Also in the case of irradiation with sterilizing lamp, the transmittance of the sample with the electric field application was 1.6 times as compared with that without the electric field application. The photocatalytic effect was improved by the electric field application during the light irradiation. The mechanism of effects by the electric field application to the sample will be examined in future.