Deposition and characterization of self-cleaning TiO2 thin films for photovoltaic application

Abstract

TiO2 is a self-cleaning material generally employed in engineering today because of its excellent physical and chemical characteristics. However, its self-cleaning behavior on photovoltaic panels has not been sufficiently studied and reported in the literature. This study synthesized, deposited and, characterized titanium dioxide (TiO2) thin film for self-cleaning photovoltaic application. The TiO2 was synthesized using the sol–gel method and spin coating was used for the deposition on glass substrate at optimized parameters. The characterization was done to ascertain the morphology, structural, chemical bond and absorption spectrum, optical properties, photocatalytic, and thin-film durability. The surface morphology shows a snowflakes-like shape and at higher magnification shows they are clustered and pockets of a linked chain. The X-ray diffraction patterns of the TiO2 thin films deposited and annealed at 600 °C displayed mainly anatase phase in its crystal structure with an average particle size of 15.82 nm. The FTIR analysis revealed prominent bands at 2921.4, 1445.5, and 463 cm−1, with high anatase Titania peaking at 463–349 cm−1. The band for TiOTi stretching vibration is observed at 489 cm−1. Water contact angle measurement proved that the thin film has a super hydrophilic tendency. The TiO2 thin film calcined at 600 °C had a thickness of 63 nm and absorbed light in the UV–visible region starting from a wavelength of 500 nm. The obtained surface morphology for the calcined film encourages photocatalytic and self-cleaning activities on the photovoltaic application as oppose to the non-calcined TiO2 thin film. The snowflake shapes bring out well-exposed surfaces that promote the valuable spectrum of sunlight adsorption on the surface per unit area.