Synthesis of Zn/TiO2 Thin Films for Self-Cleaning Applications

Titanium dioxide (TiO2) thin film has been widely used in semiconductor applications. The surface modification on TiO2 has been done by adding zinc (Zn) in order to improve surface wettability and enhance the photocatalysis efficiency for solar cell applications. Self-cleaning technology is very important to sustain the efficiency of the solar cell and reduce the cost of the maintenance of the solar cell. In this work, the sol-gel method was used due to the economic factor and its best efficiency. The sol-gel method is a wet chemical technique involving several steps, such as hydrolysis and polycondensation, gelation, aging, drying, densification, and crystallization. The X-Ray diffraction pattern shows that anatase and rutile phases were detected at 2 theta = 36.3864 degrees. It was clearly seen at 4% Zn-doped TiO2 annealed at 400 degrees C that due to the increment of Zn concentration, the phase transformed from the anatase phase to the rutile phase at high temperature. The scanning electron microscope micrograph shows that Zn concentration affects grain size. The water contact angle produced when 4% Zn-doped TiO(2 )was annealed at 300 degrees C, was 18 degrees higher than in the sample of 4% Zn-doped TiO(2 )annealed at 400 degrees C. These results clearly showed that the dopant concentration and the annealing temperature influence the properties of TiO2 for a self-cleaning application.