Efficient enhancement of solar-water-splitting by modified Z-scheme structural WO3-W-Si photoelectrodes

N-type WO3 and p-type Si can be assembled into a composite structure called Z-scheme, which is a high efficiency model for overall water splitting. However, due to the existence of Schottky barrier, its relatively low photocurrent density is still a great challenge for application. Here, a modified Z-scheme structure by inserting a W interlayer is presented. A great enhancement of photocurrent density over 10 times is achieved, which can be ascribed to the introduction of the ohmic contacts between W interlayer with both WO3 and Si layers and the elimination of Si-O bands at the interface. (C) 2014 AIP Publishing LLC.