Multifunctional transition metal doped Sb2O3 thin film with high near-IR transmittance, anti-reflectance and UV blocking features

Abstract

We present optically modified Sb2O3 thin film as a multi-functional layer that can be used as UV blocking, Near Infrared (NIR) transmitting and anti-reflecting layer suited for solar energy harvesting. Optical modifications are achieved by transition metal (Mn, Ni and Cu) doping through vacuum evaporation and solid state grinding which introduces new sidewise outgrowths emerging on the previously reported thorn structure of the film. The new structures are found growing along [110] direction, reducing the growth of thorns along [111] direction. Though the UV absorbance and wavelength range of absorbance are larger for transition metal doped Sb2O3 thin films, their UV reflectance is very low compared to the undoped films. However, they all show very good absorption in UVB and UVC regions and partial absorption in UVA region like undoped Sb2O3 thin films. Ultraviolet Protection Factor of all the films lie in the range 25–50 showing their competent UV blocking ability. NIR transmittances of Sb2O3 thin film increases with Ni and Mn doping, making them appropriate for NIR transmitting layers in cover glass of IR sensors and solar thermal energy collectors. Considering the multi-functionality, the overall performance of transition metal doped Sb2O3 thin films are more efficient than undoped film.