Indium–Tin–Oxide Nanowire Array Based CdSe/CdS/TiO2 One-Dimensional Heterojunction Photoelectrode for Enhanced Solar Hydrogen Production

For photoelectrochemical (PEC) hydrogen production, low charge transport efficiency of a photoelectrode is one of the key factors that largely limit PEC performance enhancement. Here, we report a tin-doped indium oxide (In2O3:Sn, ITO) nanowire array (NWs) based CdSe/CdS/TiO2 multishelled heterojunction photoelectrode. This multishelled one-dimensional (1D) heterojunction photoelectrode shows superior charge transport efficiency due to the negligible carrier recombination in ITO NWs, leading to a greatly improved photocurrent density (∼16.2 mA/cm2 at 1.0 V vs RHE). The ITO NWs with an average thickness of ∼12 μm are first grown on commercial ITO/glass substrate by a vapor–liquid–solid method. Subsequently, the TiO2 and CdSe/CdS shell layers are deposited by an atomic layer deposition (ALD) and a chemical bath deposition method, respectively. The resultant CdSe/CdS/TiO2/ITO NWs photoelectrode, compared to a planar structure with the same configuration, shows improved light absorption and much faster charge ...