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Bilayer SiO 2 Nanorod Arrays as Omnidirectional and Thermally Stable Antireflective Coating
Author(s) -
Khan Sadaf B.,
Wu Hui,
Li Jianghao,
Chen Limin,
Zhang Zhengjun
Publication year - 2018
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201700942
Subject(s) - anti reflective coating , materials science , omnidirectional antenna , bilayer , coating , nanorod , contact angle , optoelectronics , substrate (aquarium) , refractive index , optics , nanostructure , nanotechnology , composite material , telecommunications , oceanography , physics , membrane , biology , geology , computer science , antenna (radio) , genetics
Nature instigates researchers significantly in imitating to engender comparable properties using artificial methods, which unlocks developing trend in material science and engineering progress. Fabricating graded‐index nanostructures is an effective approach to tune and generate similar properties artificially such as the moth's eye antireflectance (AR) or lotus like superhydrophobicity. Herein, Bilayer AR coatings with periodically arranged SiO 2 hierarchical nanostructures resembling moth eyes are fabricated on dense SiO 2 matrix base layer using the versatile route of glancing angle deposition technique (GLAD). The refractive indices of monolayer SiO 2 are tuned from 1.46 to 1.08 by changing the deposition angle ( α ) from 0 to 88°. The fabricated bilayer SiO 2 AR (BSAR) film possess high optical omnidirectional broadband transparency and tunability at a desired wavelength range showing <1% reflectance. The present AR design is flexible and practically applicable to various supporting substrate materials ( η varies from 1.45 to 1.9). Furthermore, the omnidirectional BSAR films show multiple functions including enhanced mechanical strength, the thermal stability (up to 300 °C), and hydrophobic capability with a water contact angle (CA) of 147° to withstand under humid environment. This multipurpose coating provides an intriguing route in optics field for imminent research.