A dual effect of surface roughness and photocatalysis of crystalline TiO2-thin film for self-cleaning application on a photovoltaic covering glass

Abstract

A high level of transparency and rich self-cleaning thin film of TiO2 on glass substrates were synthesized using the dip-coating method. The preferred orientation (1 0 1) and (2 0 0) peaks corresponding to 2θ value of 25° and 48° respectively, confirm the anatase phase of TiO2. Surface roughness value of 9 nm has been found using atomic force microscope (AFM), which effectively prevents dust accumulation on TiO2 coated surface. Moreover, to understand soiling effect of film, TiO2 coated and uncoated substrates were investigated and compared after one week of soiling in the coal dust region. Interestingly, the TiO2-coated substrates showed 8% more transmittance than the uncoated films. Furthermore, four adhesion forces between dust particles and film surfaces were calculated. The smaller adhesion forces were inspected for the TiO2 coated thin films compared to the bare glass substrate, which designates lower dust accumulation on the substrate. In addition, the photocatalytic activity of TiO2 film showed 39.40% and 53.06% methylene blue (MB) dye degradation efficiency under sunlight and UV light exposure respectively, that helps in cleaning the surface by reacting with dirt. Our study suggests that TiO2 coated thin film is a potential candidate for self-cleaning in solar cell applications due to its high transparency, smaller particle size, lower adhesion forces and better photocatalytic activity.