Study on low-refractive-index sol-gel SiO2 antireflective coatings
Bin Shen*, Haiyuan Li, Huai Xiong, Xu Zhang, and Yongxing Tang
- Key Laboratory of High Power and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
A study on low-refractive-index antireflective (AR) coatings by a sol-gel method is reported. Variations in the properties of the coatings are related to the molar ratios of ammonia to deionized water being changed in the process of preparing the sols. From the performance test results, the optimal ratio of the reactants necessary to prepare low-refractive-index AR coatings is determined. Of all the AR coatings, the lowest recorded refractive index is 1.16 at a wavelength of 700 nm. The largest water contact angle is 121.2°, and the peak transmittance is 99.95% at a wavelength of 908 nm. Furthermore, the sol used to deposit the film with the lowest refractive index is stable because of the narrow size distribution of its constituent particles.