First-principles DFT investigation of the electronic and optical properties of Br doped rutile TiO2 for application in photovoltaic Panels’ coatings and Self-Cleaning

Abstract

Development of novel self-cleaning technologies that withstand dirtying of photovoltaic panels and maintain a tolerable cleanliness over time is of great importance. TiO2 is one of the most promising materials used in this field due to its ability to oxidize organic and inorganic substances through photocatalytic redox processes. TiO2, however, only absorbs ultraviolet (UV) light from the entire broad solar spectrum due to its large band gap energy. Doping is an effective way of modifying the band gap and broadening the solar spectrum range for the photocatalytic activity of TiO2. Thus in this study, we carry out first-principles density functional theory (DFT) calculations in order to investigate the influence of bromine doping, with Br at a Ti site, on the structure and the band gap of rutile TiO2. Optical properties such as transmittance and reflectance have also been evaluated from the calculated complex dielectric function of the doped system in order to check its suitability as self-cleaning coating on photovoltaic panels.