Green-precursor sol–gel synthesis of transparent hydrophobic silica coatings with improved self-cleaning durability

Abstract

Solar energy has become a prominent source of renewable energy; nevertheless, the dust accumulation on solar glass has been a significant contributing factor in the reduction of light transmission and power output. In this research, a green precursor sol-gel process is proposed for the fabrication of transparent hydrophobic silica coatings with enhanced self-cleaning durability for solar glass. The application of environmentally friendly precursors allowed for the fabrication of a hybrid silica matrix with low-surface-energy functional groups, which exhibited high optical transmittance (>90%) and long-lasting hydrophobicity. The effect of modifying agents such as phenyltriethoxysilane (PTES) and trimethoxyoctylsilane (TMOS) was examined for different molar ratios, as well as the incorporation of silica particles (0.04-0.063 mm). The optimal composition, obtained at a TEOS/TMOS ratio of 1:4 with the incorporation of silica particles, exhibited a water contact angle of 107.54° and a self-cleaning efficiency of 94.45% using the blade-coating technique. The durability test revealed minimal degradation in hydrophobicity after repeated washing cycles, which was attributed to the enhanced cross-linking and surface morphology introduced by the green sol-gel process. When tested on solar panels, the coating demonstrated an enhancement in current and power output of up to 43.75% compared to the uncoated solar panels under dusty conditions. In conclusion, this research work presents a green and efficient sol-gel process for the fabrication of transparent, hydrophobic, and self-cleaning silica coatings for solar glass.