Synergistic enhancing photoelectrochemical response of Bi10O6S9 with WO3 optical heterojunction in wide wavelength range

Abstract Owing to the previously reported giant incident photon-to-current conversion efficiency of a bismuth oxysulfide nanofilm, an improved composite electrode is further developed in this work by in situ growing the bismuth oxysulfide nanosheets upon tungsten trioxide nanoplate, based on a simple chemical bath deposition method. A facile synergistic optical heterojunction structure is formed by coupling the multi-dimensional interlaced heterojunctions with light-trapping structure. It is observed that the interfacial charge transfer in device is accelerated and the light absorption is enhanced even in long-wavelength range, improving the separation and transfer efficiency of photo-excited electron/hole pares. The photocurrent response of 1.16 mA cm−2 at −0.1 V (vs. saturated calomel electrode) is achieved, which is 21 times and 1.8 times higher than those of pure tungsten trioxide electrode and pure bismuth oxysulfide electrode, respectively. This unique optical heterojunction is effective and provides a potential application in general photoelectrochemical sensors.