Sputter deposited tungsten oxide thin films and nanopillars: Electrochromic perspective

Tungsten oxide (WO3) thin films and nano pillars were grown on FTO and corning substrates by using DC magnetron sputtering. Structural properties, surface morphology, optical properties, and electrochromic properties were systematically characterized by using SEM, XRD, UV–Vis Spectrometer, and Electrochemical Analyser respectively. Increased oxygen partial pressure resulted a rise in the optical transmittance from 72% to 89% at a wavelength of 600 nm. Moreover, coloration efficiency was also found to vary with partial pressures for both planar and glad from 30.48 cm2C-1 to 78.36 cm2C-1. We observe that glad deposited nano pillars showing higher coloration efficiency as compared to the planar thin film. The coloration efficiency found for the planar thin film and nano pillars at optimized partial pressure are 37.04 cm2C-1 and 78.36 cm2C-1 respectively. A strong influence of oxygen partial pressure and surface to volume ratio has been observed on the coloration efficiency, which can play a major role in the electrochromic application. •WO3 thin films were deposited at various Oxygen partial pressures as Planar and Glad using DC magnetron sputtering.•Nanostructed films were observed for Glad deposited films.•XRD analysis shows room temperature deposited samples shows amorphous nature.•The Oxygen partial pressure of 8 × 10−4 mbar and GLAD angle of 75° helps in enhancing the electrochromic attributes of WO3.