Rational Design and Construction of Well-Organized Macro-Mesoporous SiO₂/TiO₂ Nanostructure toward Robust High-Performance Self-Cleaning Antireflective Thin Films

Abstract

Antireflection (AR) thin films on optical substrates are of great significance in high-performance optoelectronic devices. Here, we present a rational design and construction of well-organized macro-mesoporous nanostructure toward robust high-performance self-cleaning antireflective thin films on the basis of effective medium theory and finite difference time domain (FDTD) simulations that combine the optical design principle. A hierarchical macro-mesoporous SiO thin film with very high porosity and gradient refractive indexes works as a λ/4-wavelength AR layer and significantly suppresses the reflection in the range from 350 to 1200 nm. Even after dip-coating a layer of high refractive index TiO nanocrystals, the nanostructured thin film still exhibits broadband AR properties which are much superior to conventional flat SiO/TiO thin films, especially in the range of 350-500 nm. In addition, the obtained thin film exhibits photocatalytic self-cleaning and durable superhydrophilicity. The advantages brought by the well-organized macro-mesoporous structure are also testified through comparing to the solely mesoporous SiO/TiO film counterpart. Moreover, the pencil hardness test and sandpaper abrasion test show favorable robustness and functional durability of the thin film, which make it extremely attractive for practical applications in optical devices, display devices, and photovoltaic cells.

Fabrication of silver nanoparticles/gelatin hydrogel system for bone regeneration and fracture treatment

“…The amount of calcium in MC3T3-E1 cells after culturing for five days in AgNPs/Gel Gel was shown in Figure-7B. Owing the higher mineralization, the calcium deposition content in AgNPs/Gel hydrogel was recorded to be 4.3 mg. Gel hydrogels alone were observed with low calcium content deposition (Jin et al., 2017 ).…”

Robust Operation of Mesoporous Antireflective Coatings under Variable Ambient Conditions

“…This has been achieved via integration of preformed nanocrystals, 20 ultrathin crystalline, 22 or mesoporous titania layers. 23 A practical problem of mesoporous ARCs, in particular, when made of high-surface-energy inorganic materials, is that pores on the subwavelength scale are susceptible to filling with ambient gas phase water molecules via capillary condensation, 24 thus resulting in a reduction of the AR effect. Hydrophobicity to suppress capillary condensation may be conferred by incorporating nonpolar functional groups during synthesis via co-condensation methods or by postsynthetic grafting.…”

A Mini Review: Antireflective Coatings Processing Techniques, Applications and Future Perspective

“…To fulfil the destructive interference, the thickness of each layer in a bilayer coating is equivalent to half (λ/2)or quarter (λ/4) of the wavelength. Different research groups fabricate bilayer AR coatings following this principle, SiN and SiO 2 [34] deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD) for solar cell applications, MgF/SiNx for crystalline solar cells [35] , SiO 2 /TiO 2 self-cleaning AR coatings are few examples of bilayer coatings [36][37][38] .…”