Photoresponse and stability improvement of ZnO nanorod array thin film as a single layer of photoelectrode for photoelectrochemical water splitting

ZnO nanorod array thin film with Al-doping and hydrogen treatment was developed as a photoelectrode combining the functions of transparent conducting oxide thin film and photoactive 1-dimensional nanostructured semiconductor into a single layer for photoelectrochemical water splitting. It was demonstrated that hydrogen treatment and Al-doping enhanced the dark currents, photocurrents, and hydrogen generation efficiencies largely and the enhancement by hydrogen treatment was more significant. The maximum photoinduced hydrogen generation efficiency was about 0.020%. Furthermore, hydrogen treatment also improved the photosensitivity and the stability under illumination significantly. The minimum decay time constant and rise time constant were 1.71 and 1.22 s, respectively. And after current–voltage scanning upon illumination for 50 cycles, the 1-dimensional morphology still remained unchanged but those without Al-doping and/or hydrogen treatment were altered seriously. The good photoresponse and stability made the Al-doped ZnO nanorod array thin film with hydrogen treatment have wide applications in the photoelectrochemical field.

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► ZnO nanorod array thin films were developed as an ITO/FTO-free photoelectrode.
► TCO thin film and photoactive semiconductor were combined into a single layer.
► Hydrogen treatment and Al-doping improved photoresponse and stability significantly.
► A photoelectrode for photoelectrochemical water splitting was developed.
► A new strategy of photoelectrode fabrication was proposed.