Electrochromic properties of radio frequency magnetron sputter deposited mixed Nb2O5:MoO3 (95:5) thin films cycled in H+ and Li+ ions

In this paper, we report on rf power induced change in structural, optical, vibrational and electrochromic properties of radio frequency (rf) magnetron sputtered mixed Nb2O5:MoO3 (95:5) films. X-ray diffraction result showed that all the deposited films belong to amorphous nature. The presence of five-valent niobium and six-valent molybdenum in the deposited film was confirmed by the x-ray photoelectron spectroscopic measurement. The maximum average optical transmittance of 76% was observed for the film deposited at 100 W rf power. The decrease in optical energy band gap may be due to the rf power induced effect gives rise to the localized state near the band edges of Nb2O5:MoO3. The longitudinal and transverse optic modes of Nb–O stretching vibrations were observed from the micro-Raman study. The cyclic voltammograms of Li+ and H+ ions clearly show all the films are having better reversibility and reproducibility in their electrochemical analysis. The maximum coloration efficiency of 69.80 cm2/C was obtained for the mixed Nb2O5:MoO3 films.