Fabrication of silica nanoparticle double layers on glass substrate and their antireflective properties

Silica nanoparticles (SNPs) of smaller diameter and mesoporous silica nanoparticles (MSNPs) of larger diameter were synthesized using a typical Stöber method and a surfactant self-assembly template method, respectively. The SNPs were used to form a thin film with a high refractive index on a glass substrate. The SNPs were surface-modified with 3-trimethoxysilylpropylacrylate (MSA), their dispersion solution was then spin-coated on a glass wafer under optimized conditions, and the coating was finally UV-cured. The MSNPs were employed to fabricate a thin film of single layer or multilayers with a low refractive index on the top of the SNP film. The MSNP films were coated by a typical layer-by-layer (LbL) technique utilizing cationic and anionic polymer solutions properly. The double layers of high and low refractive index films fabricated on the glass substrate were subjected to measurement of antireflective properties such as transmittance and reflectance. The results indicated that they were quite effective in reducing light reflection and enhancing light transmission.