Facile preparation of porous SiO2 antireflection film with high transmittance and hardness via self-templating method for perovskite solar cells

An antireflection (AR) film on the surface of the photovoltaic glass can significantly improve the photoelectric conversion efficiency of solar cells. However, AR films prepared by a facile and low-cost sol-gel method usually exhibit poor mechanical properties, which limits their applications. Herein, hexamethoxy methyl melamine resin (CYMEL 303LF) was employed as a pore-forming agent in the sol and sacrificial template to prepare porous SiO2 film on glass by a facile sol-gel method and subsequent heat treatment. The obtained SiO2 film showed a high solar transmittance increase of 3.24% in the wavelength range of 380–1100 nm and a good hardness of H when the dosage of CYMEL 303LF is 10 wt%, the short circuit current density and photoelectric conversion efficiency of the solar cell are increased respectively by 1.44 mA/cm2 and 1.08%, compared with the substrate, which is better than most SiO2 films in the previous works. With increasing the dosage of CYMEL 303LF from 0% to 12%, the solar transmittance gain was increased at first and then decreased, while the film hardness was decreased straightly. This was probably because that the introduction of CYMEL 303LF can facilitate the formation of more pores in the SiO2 film, leading to a decrease in the refractive index and film adhesion. Therefore, this work can provide a facile method to prepare high-performance SiO2 as AR film for solar cells.