Structure, photoluminescence and thermoluminescence study of a composite ZnTa2O6/ZnGa2O4 compound doped with Pr3+

• A persistent Pr3+-doped zinc tantalite/gallate phosphor was prepared at 1200 °C.
• Mixed phases were observed from the XRD corresponding to ZnGa2O4 and ZnTa2O6.
• The material was found to have mixed particle shapes.
• Prominent red emission lines were observed in the PL.
• Persistent luminescence with a decay time of 374 ± 8 s was observed.

The study of persistent luminescence is interesting for applications related to biological imaging, self-lit roads and security signs. Composite Pr-doped samples were prepared in one pot by solid chemical reaction at 1200 °C for 4 h. The X-ray diffraction patterns of the samples showed mixed phases which correspond to ZnGa2O4 and ZnTa2O6 phases. Interestingly, the secondary electron microscopy images showed that the surface morphology is composed of particles with different shapes: irregular, rhombus and rod shapes. The X-ray maps obtained using field emission scanning electron microscopy, confirmed that the irregular particles correspond to ZnTa2O6, and the rods correspond to ZnGa2O4. Red emission was observed from 1D2 → 3H4, 3P0 → 3H6, 3P0 → 3F2 and 1D2 → 3H5 transitions of Pr3+. The lifetime of the persistent luminescence was measured, and the corresponding trapping centres were investigated using thermoluminescence spectroscopy.

Figure optionsDownload high-quality image (273 K)Download as PowerPoint slide