Single-step soft-imprinted large-area nanopatterned anti-reflection coating
We demonstrate an effective nanopatterned antireflection coating on glass that is based On sol gel chemistry and large-area substrate-conformal soft-imprint technology. The printed 120 nm tall silica nanocylinders with a diameter of 245 nm in a square array with 325 nm pitch forth an effective-Index (n = 1.20) antireflection coating that reduces the double-sided reflection from a borosilicate glass slide from 7.35% to 0.57% (averaged Over the visible spectral range) with a minimum reflectance <0.05% at 590 nth. The nanoglass coating is made using a simple process involving only spin, coating and an imprint step, without vacuum technology or annealing required. The refractive index of the nanoglass layers can be tailored over a broad range by controlling the geometry (1.002 < n < 1.44 in theory), covering a wide range that is not achievable with natural materials. We demonstrate that the nanoglass coating effectively eliminates glare from smart-phone display windows and significantly improves the efficiency of glass-encapsulated solar cells. These features, that are achieved over an angular range as wide as +/- 50 degrees, together with strong hydrophobicity and mechanical durability, make nanoglass coatings a promising technology to improve the functionality of optoelectronic devices based on glass encapsulation.
van de Groep, J, Spinelli, P, & Polman, A. (2015). Single-step soft-imprinted large-area nanopatterned anti-reflection coating. Nano Lett., 15(6), 4223–4228. doi:10.1021/acs.nanolett.5b01623