Enhanced visible light photocatalytic properties of TiO2 thin films on the textured multicrystalline silicon wafers

Abstract

TiO₂ thin films were grown on solar-grade (SoG) multicrystalline silicon (mc-Si) wafers with different multiscale structures by using a liquid phase deposition (LPD) method. It was found that due to the carrier injection from mc-Si wafers, the photocatalytic activity of the TiO₂ films could be expanded from the ultraviolet to the visible light region. In addition, further enhanced visible light photocatalytic properties could be achieved by introducing a nano-texture and p–n junction into the mc-Si wafer, which was ascribed to the excellent light trapping and strong carrier separating properties. Our results suggest that density-graded nanostructures applied to the TiO₂ photocatalyst can enhance optical absorption, benefit carrier separation, and improve photocatalytic activity.