Surface oxygen vacancies of ZnO: A facile fabrication method and their contribution to the photoluminescence

We develop a novel approach to create oxygen vacancies on the surface of ZnO particles and investigate their role in the photoluminescence of the ZnO. In this approach, the commercial ZnO powder is coated with a thin carbon layer using ball-milling technique, forming ZnO@C core@shell particles. By annealing the as-milled ZnO@C at a relatively low temperature (i.e., up to 600 degrees C) in oxygen, the surface oxygen vacancies are formed, which is confirmed by X-ray photoelectron spectroscopy analyses. The annealed powders show red photoluminescence, which largely covers the far-red region, and by varying the annealing temperature, the emission range of the ZnO can be tailored. We found that the far-red emission is associated with the surface oxygen vacancies of ZnO. (C) 2019 Elsevier B.V. All rights reserved.