Self-Templated Fabrication of Robust Moth-Eye-Like Nanostructures with Broadband and Quasi-Omnidirectional Antireflection Properties

Antireflection coatings (ARCs) have been realized by "bottom-up" depositing self-templated moth-eye patterns on glass substrates. The substrates were dip-coated by a layer of silica nanoparticles and further textured into patterns of nanodomes by precursor-derived one-step assembly (POA) of a mesoporous silica layer. Typically, the compact stacked nanodomes were about 260 nm in width and about 90 nm in height, under which was a layer comprising the lower halves of silica nanoparticles and mesoporous silica layer. The protuberant nanodomes with quarter-wavelength thickness and smoothly varying refraction index make significant contributions to the realization of broadband and quasi-omnidirectional antireflection. The mesoporous silica layer grown on the surface of silica nanoparticles and substrate through chemical bonding endows the coating with excellent structural integrity, thus, guaranteeing the high mechanical durability of the coating. The optimized coating reduces the double-sided reflection of glass from 8.75% to 1.88% over the wavelength range of 400-1200 nm. A considerable AR effect was also observed over an angular range as wide as 40. Silicon solar cells covered with this nanostructured glass showed enhancement in conversion efficiency by 4.91% at normal incidence as compared to under blank glass, which went up to 31.90% at an incidence angle of 60 degrees. Tape peeling test, sponge washing test, and pencil hardness test showed favorable robustness and functional durability of the coating, which promises great potential for applications in sunlight harvest, solar energy conversion, and optical devices.