Mesoporous sol-gel based SiO2 thin films with ordered pore orientation as antireflective coatings on glass

• Antireflective coatings on glass have increasing applications, on e.g. cover glass of PV modules, display glass, spectacle lenses or window glazing’s. Sol-gel derived mesoporous coatings can be tuned both in terms of porosity and thickness, thus allowing tuning of the refractive index. Additionally, the sol-gel approach is bottom-up, which facilitates easy upscaling. In the current work we present dip-coated mesoporous silica coatings of different pore orientation and film thickness prepared on microscope glass slides and silicon wafers. The silica coatings were derived from TEOS (tetraorthosilicates) mixed with ethanol and diluted HCl. Hexagonal and cubic pore ordering of the thin films with a pore size in the range of 5-10 nm were obtained. The thin films were characterized in terms of non-contact profilometry, stylus profilometry,  nanohardness, scratch resistance, UV-Vis-NIR transmittance and UV-Vis-NIR reflectance. The thicknesses of the studied films varied from 100 nm up to several hundreds of nm without jeopardizing the film homogeneity. All the mesoporous films exhibited higher transmittance than the uncoated glass substrate. The film with hexagonal pore orientation has a somewhat higher nanohardness than the cubic one, however,  no difference was found in the scratch resistance for the films with different pore orientations.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Nanoteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Nano-technology (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

Nyckelord

Anti-reflective coating

mesoporous silica coating

sol-gel coating

ordered pore orientation

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