The coupled effect of oxygen vacancies and Pt on the photoelectric response of tungsten trioxide films

Abstract

In this paper, four kinds of WO₃ films, namely, Pt-loaded hydrogenated WO₃, Pt-loaded WO₃, and hydrogen-treated and untreated WO₃ films were synthesized and their photoelectric properties were investigated at room temperature. The quantitative results showed that the gas-sensitized WO₃ film in formaldehyde exhibited much higher photocurrent than that in air. In addition, the sensitivity of Pt-loaded hydrogenated WO₃ to formaldehyde reached 15.8 which was nearly 15 times higher than that of the others. Moreover, Pt-loaded hydrogenated WO₃ shows excellent electrical response towards formaldehyde in the dark. The intriguing performance of the Pt-loaded hydrogenated WO₃ film indicates an efficient coupled effect of oxygen vacancies and Pt. The results provide the potential for improving the efficiency of photoelectric sensing devices by coupling two modification mechanisms. To explain the response characteristics of the four kinds of WO₃ films, a schematic diagram of the band bending and spill over model are proposed.