Preparation of novel SiO2 protected Ag thin films with high reflectivity by magnetron sputtering for solar front reflectors

The Essential Macleod Program (EMP) has been used to successfully assist in the design of a SiO2 protected Ag thin film. The film is applied through magnetron sputtering onto a glass substrate for use in a solar front reflector. In the following experiments, Ag films were first deposited on glass substrates using direct current (DC) magnetron sputtering, and then SiO2 films were deposited as a protective layer onto the surface of the Ag films using radio frequency (RF) magnetron sputtering. The reflectivity of the obtained samples was calculated and tested under light wavelengths ranging from 250 to 2500 nm with films of Ag and SiO2 of different thicknesses. The solar reflectivity (SR) and the light reflectivity (LR) of the 130 nm Ag film and the 320 nm SiO2 film were found to be up to 96.66% and 98.84%, respectively, which is almost identical to the calculated results based on the designed model. Additionally, the deposited films exhibited high anti-corrosion properties in harsh abrasion and aging resistance tests. More importantly, the films were proven capable of operating in high-temperature systems by testing under different annealing temperatures. The high performance of the films was attributed primarily to the SiO2 layer, which served as a good means of protection without experiencing serious degradation of reflectivity, demonstrating their potential in applications for solar front reflectors. (C) 2012 Elsevier B.V. All rights reserved.