Antireflection, superhydrophilic nano-porous SiO2 coating based on aerosol impact spray deposition technique for solar PV module

Abstract

In this research, silica nano-particles are deposited over the borosilicate glass and silicon wafer substrates by indigenously developed Aerosol impact deposition assembly using SiH4, oxygen, and helium as precursors. The coating process involves deionization of gases leading towards nucleation sites for silica in the presence of plasma, while tuning the pressure difference between reaction and deposition chamber controls the coating thickness, porosity, and refractive index. The deposited coating layer on the substrate enhanced the transmittance to 99.6% at 600 nm wavelength. The induced porous nature and the graded index of the coated layer as observed from the AFM and SEM resulted in superhydrophilic behavior with a water contact angle of near to 0°. The super-hydrophilicity of the coating contains self-cleaning properties, suggesting an improvement of the performance of solar PV modules as well.