Investigating the Influence of Synthetic Environments on the Electronic Structure and Luminescence of Cr-doped Zinc Gallate
Abstract
Cr doped ZnGa2O4 (Cr-ZGO) has shown potential in the field of bioimaging. To achieve the nano-size suiting for bioimaging, Cr-ZGO is normally synthesized using a hydrothermal method. There are few studies on how the hydrothermal conditions influence the structure and optical properties of the Cr-ZGO. The first two parts of this thesis study how different hydrothermal temperatures and pH environments will affect the optical properties of Cr-ZGO by photoluminescence spectroscopy. By combining the electronic structure information extracted from X-ray absorption near-edge structures (XANES) and extended X-ray absorption fine structure (EXAFS), a relationship among hydrothermal conditions, optical properties and electronic structure is built. The last part studies how the surface functionalization will affect the optical properties of Cr-ZGO synthesized under different hydrothermal conditions. It turns out oxygen vacancies around Zn will improve the emission intensity, Cr-ZGO synthesized at a low pH environment shows the strongest emission after functionalization.