Fabrication of mechanically robust, self-cleaning and optically high-performance hybrid thin films by SiO₂&TiO₂double-shelled hollow nanospheres

Abstract

Low-cost antireflection (AR) thin films on large-area optical surfaces are important for high-performance optical devices, display devices and photovoltaic cells. In the current work, SiO2&TiO2 double-shell hollow nanospheres (DSHNs) were designed, synthesized and utilized as building blocks for fabricating multifunctional AR thin films. By optimizing the porosity of SiO2&TiO2 DSHN and thin film structure, substrates with DSHN thin films attained transmittance as high as 99.4% and average transmittance up to 98.5% in the visible region. The nano-composite SiO2-TiO2 films exhibited intrinsic superhydrophilicity, anti-fogging and high photocatalytic activity. Tape peeling test, sponge washing test, and high temperature and moisture proof test showed favorable robustness and functional durability of the thin films, which make them extremely attractive for applications in lenses, photovoltaic cells and windows of high-rise buildings.

Three‐Layered Hollow Nanospheres Based Coatings with Ultrahigh‐Performance of Energy‐Saving, Antireflection, and Self‐Cleaning for Smart Windows

“…Inspired by our previous studies, SiO 2 /TiO 2 /VO 2 TLHNs with unique architecture design were prepared by a facile solution‐based method. In the synthesis protocol ( Figure a), polyacrylic acid (PAA) was used as a template and enclosed by the precursors of SiO 2 , TiO 2 , and VO 2 in succession.…”

Water drop-surface interactions as the basis for the design of anti-fogging surfaces: Theory, practice, and applications trends

“…Coatings with anti-fogging activity can also be prepared by immobilizing inorganic nanoparticles (typically SiO2 and TiO2) either in a network of hydrophilic polymers on the substrate (e,g., PVA, PVP, and PEGMA [135], glycidoxypropyltrimethoxysilane [136] or a catecholconjugated polymer [137]) or on the substrate by direct deposition using sol-gel [138] or aqueous solutions [139]. The use of mesoporous silica nanoparticles (MPSNPs) [140,141], hollow silica nanospheres (HSNs) [142], double-shell hollow nanospheres of SiO2/TiO2 (DSHNs) [143], and solid silica nanoparticles (SSNPs) [144], among others, as building blocks allows for the fabrication of anti-fogging films with hierarchical roughness featuring spreading mechanism (high specific surface). Coatings made up of SSNPs deposited on La(OH)3 nanorods prepared by You and colleagues [145] have proven remarkable capacity to alleviate surface fog (WCA ≈ 0°) and minimize light reflection under sun exposure.…”

Closed-Surface Multifunctional Antireflective Coating Made from SiO2 with TiO2 Nanocomposites

“…Tao et al [18] reported a broadband TiO 2 -SiO 2 stack coating via an LBL technique; a maximum transmittance of 96.0% was achieved, and the film surface showed excellent superhydrophilicity (water contact angle ≈ 3.0 • ) and antifogging properties. Yao et al [19] prepared an AR sol-gel with SiO 2 -TiO 2 double-shell HNs in which a TiO 2 shell layer was grown on the silica HNs. It displayed a maximum transmittance of 99.4%, with an average transmittance of 98.5% in the visible region.…”