Design and preparation of broadband antireflective coatings with excellent mechanical properties

Abstract

Double antireflective coatings with broadband, high-transmittance and scratch-resistance properties were prepared in this research by sol-gel method. The bottom layer was the mixture of silica nanoparticles and linear silicate polymers (SiO2 NPs-LPs) obtained from base/acid two-step catalyzed tetraethyl orthosilicate (TEOS), while the top layer was the mixture of hollow silica nanoparticles and linear silicate polymers (HSiO2 NPs-LPs). By optimizing the refractive index and the thickness of the double coatings, the optical performance of the double coatings was generally consistent with the results of theoretical design. The average transmittance in the wavelength range of 400-1200 nm reached 99.1%.Besides, through applying hydroxyl modification on the surfaces of silica particles and hollow spheres, the antireflective coatings exhibited excellent mechanical properties, with its pencil hardness reaching 5 H and critical load for scratch being 28.9 N. All these good features have made this coating promising in harsh outdoor conditions.

Hollow Rodlike MgF2 with an Ultralow Refractive Index for the Preparation of Multifunctional Antireflective Coatings

“…The hollow-structured material can reduce the refractive index of the body material by wrapping the air with a refractive index of 1, so it is one of the most effective means for preparing the low-refractive-index coatings. Commonly, hollow-structure SiO 2 is adopted to prepare the antireflective coating with a low refractive index. , Because MgF 2 has the lowest refractive index among the existing numerous inorganic materials (with a refractive index of 1.38), it is of great advantage to prepare the coating with an ultralow refractive index by MgF 2 . , However, the synthesis of MgF 2 nanoparticles with a hollow structure has not been reported so far. By using the hollow-structured MgF 2 , it is possible to prepare a coating with an ultralow refractive index.…”

“…12,13 Because MgF 2 has the lowest refractive index among the existing numerous inorganic materials (with a refractive index of 1.38), it is of great advantage to prepare the coating with an ultralow refractive index by MgF 2 . 14,15 However, the synthesis of MgF 2 nanoparticles with a hollow structure has not been reported so far. By using the hollowstructured MgF 2 , it is possible to prepare a coating with an ultralow refractive index.…”

Toward Sustainable, Colorless, and Transparent Photovoltaics: State of the Art and Perspectives for the Development of Selective Near‐Infrared Dye‐Sensitized Solar Cells

“…As aforementioned, hollow structure are used to prepare low refractive layer [327] and MgF 2 is a very interesting material for ARCs as it presents the lowest refractive index among inorganic materials (n = 1.38). [328,329] Bao et al [313] have achieved an ARC consisting of a bottom layer made of chemically bonded silica nanoparticles and a top layer made of hollow MgF 2 nanorods with a refractive index that can be adjusted from 1.10 to 1.35. Another design of ARCs is "Moth-eye" like texture; able to limit reflection due to the presence of a spatially ordered array of sub-micrometric dots.…”