Enhanced light absorption and charge separation of In‐doped ZnO nanorod arrays for photoelectrochemical water‐splitting application

Abstract

Elemental doping promises an efficient strategy to modify and optimize the performance of metal oxide photoanodes. Herein, we introduce a simple hydrothermal method to fabricate In-doped ZnO thin films on the fluorine-doped tin oxide (FTO) to use as a photoanode for water splitting application. The effects of In-doping on the structural, optical, morphological, and electrical properties of ZnO nanorods were studied. PEC results indicate that the 5% In doped ZnO photoanode determined an outstanding photocurrent density reached 0.42 mA/cm2 at 0.64 VAg/AgCl, which is four times higher than the undoped ZnO sample (0.1 mA/cm2). Furthermore, Ultraviolet-visible spectroscopy (UV-Vis) and photoluminescence spectroscopy (PL) studies showed a red-shift in the band edge of doped samples compared to the pure samples, which indicate that the light absorption is enhanced. We find that the optimal doping of In (5%) leads to smaller charge transfer resistance and higher electron transfer rate as confirmed from EIS analysis. Therefore, fabricated In-doped ZnO could be a favorable and potential photoelectrode for light-harvesting and water splitting application.