Effect of phase structure on the photoluminescence properties of Er3+-doped CaWO4 mineral materials

Abstract

The incorporation of rare earth elements into the mineral materials of natural phosphors is beneficial for effectively regulating the photoluminescence (PL) properties of minerals and improving the utilization rate of mineral materials. Er³⁺-doped CaWO₄ ceramics are prepared by applying a high-temperature solid-state reaction method, and the average grain size of the doped ceramics is greatly reduced. The PL properties of the ceramics are closely related to their crystal phase structure and symmetry. When the doping concentration is 0.2 mol%, the phase structure and microstructure of the ceramics are significantly changed and lattice symmetry is minimal; therefore, the PL intensity reaches the maximum value with a relative change of 225.8% in the PL intensity. When the temperature increases to 180 °C, all the ceramics have good fluorescence thermal stability. The CIE color coordinate of CaWO₄:0.2%Er³⁺ ceramic is found to fall in the green region of the visible spectrum and has the longest fluorescence lifetime of up to 52.3 μs. This study shows that the excellent PL properties of CaWO₄:0.2%Er³⁺ ceramics lay a foundation for the research on mineral fluorescent ceramics in the fields of optical temperature measurement, LEDs, optical imaging and display, thus expanding the application of scheelite ceramics in the optical field.