Contact: Andreas Schueler
In contrast to anti-reflection coatings on eyeglasses, photographic lenses etc., which need only to be anti-reflected in the visible spectral region (380 nm – 780 nm), a solar collector glazing has to be anti-reflected within the full solar spectrum. For this purpose, thin film materials with a refractive index lower than that of silicon dioxide are desired.
Applying materials with a lower refractive index than silicon dioxide (refractive index approx. 1.46) allows for a larger spectral region of anti-reflection as compared to coatings based on materials with the refractive index equal or higher than that of silicon dioxide.
The low-n antireflection coatings have ot be durable under outdoor conditions for the full lifetime of the solar collectors (typically more than 25 years).
V. Hody-Le Caër, E. De Chambrier, S. Mertin, M. Joly and M. Schaer et al. Optical and morphological characterisation of low refractive index materials for coatings on solar collector glazing, in Renewable Energy, num. 53, p. 27-34, 2013