Cu doped ZnO nanorods with controllable Cu content by using single metal organic precursors and their photocatalytic and luminescence properties

Controlled doping into nanomaterials is an enabling technology for functional nanodevices, but still challenging. We report the accomplishment of a facial growth method of controlling Cu doping concentration into ZnO nanorod arrays systematically as an example by faith transfer of Cu content in single hybrid bimetallic organic precursors, zinc copper acetylacetonate, to the end ZnO nanorod arrays using solution method. The incorporation of Cu content is demonstrated to vary from 0 at.% to 10 at.% with a step of 2 at.%, where the control over the accuracy of Cu content can be better. The as-synthesized nanorods of around 150 nm in diameter are characterized by single crystallinity. The systematic Cu incorporation is proved by energy dispersive spectroscopy and X-ray diffraction. Photoelectron spectroscopy shows that the ratio of Cu+2 to Cu+1 varies accordingly, an increasing trend with total Cu doping concentration. The optical and photocatalytic properties of the Cu-doped ZnO nanorods are thus studied. The results reveal that the photodegradation of methyl orange is facilitated with Cu doping and the role of multi-valences of Cu ions on surface is proposed. Several unique features in photoluminescence also accompany with Cu doping, including the UV peak shift toward longer wavelength, the decrease of UV/visible intensity ratio, the increase of visible light emission and the shift of visible light emission from green to orange.