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Robust operation of mesoporous antireflective coatings under variable ambient conditions

preprint
submitted on 04.12.2017 and posted on 05.12.2017 by Barry Reid, Yinong Chen, Benjamin Schmidt-Hansberg, Stefan Guldin
Antireflective coatings (ARCs) are important components in optical applications due to their ability to reduce reflection and maximize transmission of light across interfaces. Generating mesoporous films with adequate film thickness and refractive index is a common method to achieve amplitude and phase matching in low-cost single- layer interference-based ARCs. For high surface energy materials, pores on the 2 - 50 nm, i.e. the sub-wavelength scale, are subject to capillary condensation, and pore filling by surrounding gas phase water molecules at size-characteristic humidity values hampers their functioning. In this work, we examine the effect of relative humidity on mesoporous ARCs and present a simple method for the preparation of ARCs with robust operation under variable conditions. The materials route is based on the generation of well-defined porous aluminosilicate networks by block copolymer co- assembly with poly(isobutylene)block-poly(ethylene oxide) and post-synthesis grafting of trichloro(octyl)silane molecules to the pore walls. The functionalized films exhibited a maximum transmittance value of 99.8% with an average transmittance of 99.1% in the visible wavelength range from 400 nm to 700 nm. Crucially, the AR performance was maintained at high humidity values with an average transmittance decrease of only 0.2% and maximum values maintained at 99.7 %, which compared to maximum and average losses of 3.6% and 2.7 %, respectively, for non-functionalized reference samples. The ARCs were shown to withstand at least 50 humidity cycles, indicating long-term stability against fluctuating environmental conditions.

Funding

EPSRC Industrial Case Award (EP/M506448/1)

History

Topic

  • Coating Materials

Email Address of Submitting Author

s.guldin@ucl.ac.uk

Institution

University College London

Country

United Kingdom

ORCID For Submitting Author

0000-0002-4413-5527

Declaration of Conflict of Interest

There are no conflicts to declare.

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in ACS Applied Materials & Interfaces

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