Effect of Argon to Oxygen Ratio on the Properties of Tungsten Oxide Films Prepared by Direct Current Reactive Magnetron Sputtering

Abstract

In this study, tungsten oxide films were fabricated on ITO-coated glass substrates using DC reactive magnetron sputtering with varying argon to oxygen ratios. The influence of these ratios on the microstructure and electrochromic properties of the resulting WO3 films were examined. The microstructure was characterized using X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy, which allowed for the determination of the percentage of atoms in the film. The surface morphology and roughness were measured using atomic force microscopy, while the film thickness was determined using a profilometer. The electrochromic properties of the tungsten oxide films were evaluated using a combination of ultraviolet-visible spectrophotometer and electrochemical workstation. The findings suggest that the electrochromic properties of the tungsten oxide films can be effectively tuned by manipulating the argon to oxygen ratio. Specifically, the tungsten oxide films exhibited optimal electrochromic performance when sputtered with an argon to oxygen ratio of 50 sccm:10 sccm (flux ratio). This resulted in a large optical modulation amplitude (ΔT = 56.97%), fast switching speed (tc = 5.8 s, tb = 3.4 s), high coloring efficiency (CE = 52.5 cm2/C), and stable ion storage capacity. These results highlight the potential of magnetron sputtering engineering techniques in the development of high-performance electrochromic films.