Moth-eye-like antireflection coatings based on close-packed solid/hollow silica nanospheres

Broadband antireflection coatings (ARCs) attract increasing attentions due to the effective reduction of reflection between the interface of air and substrates over a broad range of wavelengths. Moth-eye-like array ARCs with high antireflection performance have been successfully fabricated via a facile and low-cost sol–gel method using solid silica nanospheres (SSNSs) and hollow silica nanospheres (HSNSs). The composite of SSNSs and HSNSs was closely arranged on the glass substrate to firstly construct the close-packed solid/hollow silica nanospheres (c-S/HSNSs) array, in which HSNSs were used to regulate the refractive index and many triangular grooves among adjacent nanospheres were formed. Then moth-eye-like array structure was obtained by locating the nanospheres on the groove positions in c-S/HSNSs array. The transmittance of glass substrates with moth-eye-like array structure has been increased from 91.0% to 99.0%, with an average solar transmittance of 97.8%. The reflection of glass substrates with moth-eye-like array structure was prominently reduced in wide-angle incidence, and the minimum reflectance changed from 0.17% to 1.34% within 8 to 60°. The moth-eye-like array structure exhibits the high antireflection performance and excellent thermal stability and is promising in photovoltaic modules, optical lenses, and other outdoor applications.