Room temperature large-area nanoimprinting for broadband biomimetic antireflection surfaces

Ordered arrays of subwavelength hydrogen silsesquioxane (HSQ) nanorods on glass substrates are fabricated using room temperature nanoimprint lithography and anodized aluminum oxide membranes. Moth-eye type nanorod arrays exhibited superior omnidirectional antireflection characteristics in visible wavelengths. The ellipsometric measurements revealed that average specular reflection is remaining below 1% up to 55° incidence angles. Transmission measurements at normal incidence resulted in significant increase in transmitted light intensity with respect to plain glass. Simulations showed that up to 99% transmission could be obtained from double sided tapered HSQ nanorod arrays on HSQ thin film and glass substrates. Achieving large-area, broadband and omnidirectional antireflective surfaces on glass pave the way for applications including photovoltaics.