10:15 〜 10:30
▲ [7a-A202-4] Improvement of adhesion and rigidity of TiO2 thin film by laser radiation
キーワード：Semiconductor, Laser, Photovoltaics
Titanium dioxide (TiO2) is a wide band gap metal oxide semiconductor with numerous applications in science and technology. The main fields are photovoltaics and photocatalytic water purification. Most studied TiO2 polymorph phases are anatase, rutile and brookite. In recent years, researchers started to focus on development of flexible dye sensitized and perovskite solar cells. In this study, the effects of laser radiation were investigated on the TiO2 thin film adhesion to the substrate. TiO2 thin films were prepared by the spray pyrolysis technique on glass substrates from TiO2 nanoparticles. The spray solution was prepared from 0.3 g of TiO2 Degussa P-25 powder, 20 ml ethyl alcohol (C2H5OH and 5 drops of Triton-X. After the heat treatment in furnace at 500°C for 3 h, samples were modified by a direct laser write technique. In this study we have used 1064 nm pulsed nanosecond Nd:YAG laser with pulse duration of 6 ns. Adhesion to the glass substrate was tested by sonication with 120 W power at 38 kHz in water for 1, 3 and 5 min. Raman spectroscopy was used to determine a polymorph phase change. Confocal microscope was used to characterize the morphology. Raman spectroscopy results showed that the pristine TiO2 thin film consists of anatase and the crystalline phase does not change after irradiation by the laser. Laser irradiation leads to the sintering of TiO2 nanoparticles without a change of the polymorph phase according to the Raman spectroscopy results. Moreover, during sonication, the sintered TiO2 thin film is more rigid and has higher adhesion to the substrate than the pristine TiO2 thin film. The improved adhesion of the TiO2 can be utilized in flexible solar cells to increase durability and lifetime. This will also contribute to the photovoltaic efficiency because of reduced micro-cracking and exfoliation of the TiO2.