Novel-type nanostructured SiO₂ antireflection coatings and their application in Cu(In,Ga)Se₂ solar cells

Broadband antireflection coatings (ARCs) are a considerable way to sufficiently harvest more solar light into the solar cells due to dramatically reducing the reflection losses at the surface of substrate. Novel structures consisting of continuous SiO₂ film and monodispersed SiO₂ nanospeheres (NSs) array are proposed to fabricate ARCs according to mimicking the moth-eye-like nanostructure with a periodic sub-wavelength protuberance. Three distinct architectures of coatings based on SiO₂ film and SiO₂ NSs were successfully obtained by sol-gel dip-coating and electrostatic self-assembly technique, and the structural, morphological and optical properties of the coatings were investigated. Antireflection functionality of the coatings is achieved over the solar spectrum, and the solar transmittance of the substrate in visible region is increased by 7.02% on average with maximum of 8.21% by introducing coating of SiO₂ NSs/SiO₂ film. The power conversion efficiency of Cu(In,Ga)Se₂ solar cells is clearly increased from 11.66% to 12.59% by using with as-prepared ARCs. The novel-type nanostructured ARCs are promising materials in both optical and photovoltaic applications.