Reducing soiling issues on photovoltaic panels using hydrophobic self-cleaning coating

Abstract

Surfaces that simultaneously exhibit hydrophobicity, high contact angle, and high transmission of visible light are of interest for many applications such as optical devices, photovoltaic (PV) panels, and self-cleaning windows. The fabrication of such surfaces is challenging due to the competing goals of hydrophobicity and transmittance in terms of the required degree of surface roughness. In this study, the sol–gel method was used to create rough surface hydrophobic coating to reduce soiling issues on PV panels. A solution was prepared using three different materials including vinyltriethoxysilane (VTES), tetraethoxysilane (TEOS), and tetrabutoxytitanate (TTBU) called VTT (VTES–TEOS–TTBU) sol as the organic–inorganic hybrid sol. Then, this sol was applied onto glass substrates using the spin-coating method for laboratory-scale working samples. Coated samples were produced into two sets with different composition of titanium alkoxide using post-addition of water to titanium alkoxide (PWTA) and chemically modified titanium alkoxide (CMTA). The samples were then undergone surface morphological and transmission analysis. The effects of different composition were examined with respect to the contact angle, surface roughness, and optical transmittance. Based on the results obtained, CMTA sample with the highest post-bake thermal treatment (150 °C) possessed the best characteristics for hydrophobic sol–gel-based self-cleaning coating compared to the PWTA sample. This sample shown the highest contact angle (110.01°), surface roughness (0.452 nm), and transmission percentage (96% centered at 571 nm of wavelength). All coating samples were prepared in ambient condition with promising performance, eliminating the need for controlled condition based on previous researches to suit the varied temperature and humidity for different coating preparation.