Enhanced photocatalytic performance in atomic layer deposition grown TiO2 thin films via hydrogen plasma treatment

Abstract

The authors report the effect of hydrogen plasma treatment on TiO2 thin films grown by atomic layer deposition as an effective approach for modifying the photoanode materials in order to enhance their photoelectrochemical performance. Hydrogen plasma treated TiO2 thin films showed an improved absorption in the visible spectrum probably due to surface reduction. XPS analysis confirmed the formation of Ti3+ states upon plasma treatment. Hydrogen plasma treatment of TiO2 films enhanced the measured photocurrent densities by a factor of 8 (1 mA/cm2 at 0.8 V versus normal hydrogen electrode) when compared to untreated TiO2 (0.12 mA/cm2). The enhancement in photocurrent is attributed to the formation of localized electronic states in mid band-gap region, which facilitate efficient separation and transportation of photo excited charge carriers in the UV region of electromagnetic spectrum.