Refractive Index Tunable Nanoporous SiO2 Thin Film and Its Application to Mechanically Robust Broadband Anti-Reflection

Abstract

In this study, we demonstrate refractive index tunable nanoporous SiO2 thin film and it applied to moth-eye patterned substrate to improve the mechanical properties. Here, we successfully developed a simple fabrication method for the nanoporous SiO2 thin-film with ZnO-SiO2 nanoparticles mixed solution coating and ZnO wet-etching process which has a value lower than 1.35. In addition, a moth-eye structure was easily fabricated using a direct printing method, which has some merits for simplicity, cost-effectiveness and mass production. Then, we combined the nanoporous SiO2 thin film on the moth-eye-structured glass to achieve mechanical robustness and broadband anti-reflection, with the film having a transmittance of over 95% and a pencil hardness of 8H.