ZnO–SiO2 composite coating with anti-reflection and photoluminescence properties for improving the solar cell efficiency

Photoluminescence and anti-reflection both have the potential to improve solar cells efficiency. In order to obtain a coating with photoluminescence and anti-reflection both properties, in this paper, ZnO nanoparticles as photoluminescent materials were added into SiO2 sol to prepare anti-reflection coatings by the dip-coating procedure. Different contents of polyethylene glycol were added to the ZnO–SiO2 composite sol to adjust the refractive index of the ZnO–SiO2 coatings. The peak transmittance of the best coating is up to 98.37% at 615 nm and the average transmittance in the 400–1100 nm band is 95.64%. Our results prove that photoluminescence can further improve the utilization of light in the 300–400 nm band. In general, the ZnO–SiO2 coating can increase the photovoltaic conversion efficiency by 6.25%. Therefore, the results show that the ZnO–SiO2 coatings with anti-reflection and photoluminescence have potential applications in Si solar cells and other photovoltaic systems.