Tuning photoluminescence properties of ZnO nanorods via surface modification

Zinc oxide (ZnO) is a versatile material that has been used in photocatalysis, solar cells, chemical sensors, and piezoelectric transducers. All these are directly related to its surface properties. Here ZnO nanorod arrays were successfully synthesized by electrochemical deposition method, the surface of which was modified by dopamine, a robust anchor. Compared with pristine ZnO sample, the surface modification can greatly enhance the ultraviolet and visible-light photoluminescence. This is due to the formation of polydopamine on the nanorod surface, which may act as a dye that can be photoexcited. The resultant photogenerated electrons can inject into the conduction band of ZnO and take part in the luminescent process. These results may provide a foundation for real applications of ZnO nanomaterials in optoelectronic devices and, especially, for the applications in biological field as both the dopamine and ZnO are biocompatible materials. -- Highlights: ► ZnO nanorod arrays are prepared via a simple electrochemical deposition method. ► Photoluminescence of ZnO nanorods can be greatly enhanced via dopamine treatment. ► Dye-like polydopamine can be formed on the nanorod surface upon dopamine treatment. ► Photogenerated electrons in polydopamine can inject into conduction band of ZnO. ► Enhanced photoluminescence is because more electrons can contribute to it.