Films Consisting of Innumerable Tapered Nanopillars of Mesoporous Silica for Universal Antireflection Coatings. Issue 10 (14th April 2016)

• Record Type: Journal Article
• Authors: Miyata, Hirokatsu; Kitamura, Shin; Watanabe, Masatoshi; Takahashi, Masahiko
• Is Part Of: Chemistry, an Asian journal. Volume 11:Issue 10(2016)
• Page Start: 1618
• Page End: 1623
• Publication Date: 2016-04-14
• Subjects: mesoporous materials -- nanostructures -- refractive index matching -- silicates -- thin films; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/asia.201600271
• Languages: English
• ISSNs: 1861-4728

Abstract

Abstract: Films with a fine structure consisting of innumerable nanopillars of mesoporous silica (MPS) are formed by a reactive ion etching process with a fluorine‐containing gas. Each nanopillar has a tapered shape with a uniform height, which effectively suppresses reflection by the formation of an ideal graded refractive index structure. The nanopillars are spontaneously formed under low‐pressure conditions, wherein locally deposited Al−F compounds, originating from an alumina plate in the etching chamber, work as a fine etching mask. The high etching rate of the MPS film allows a very high aspect ratio of the nanopillars. The refractive index of the MPS nanopillars can be universally tuned by a controlled incorporation of TiO2 into the mesopores, which results in effective reduction of reflectance on a given substrate. The outstanding antireflection performance is experimentally demonstrated for glass substrates with a wide refractive index range. Abstract : Don't bounce back ! Films with a fine structure consisting of nanopillars of mesoporous silica (MPS) are formed by a reactive ion etching process with a fluorine‐containing gas. These antireflection coatings enable fine‐tuning of the refractive index (see figure).