Preparation,crystal structure and luminescence properties of red-emitting Lu3Al5O12: Mn4+ ceramic phosphor

A series of red-emitting Mn⁴⁺ doped Lu₃Al₅O₁₂ (LuAG) ceramic phosphors were successfully prepared by a simple solid-state reaction method in a high-temperature muffle. MgO was co-doped as sintering aids and Mg²⁺ ions helped to realize the charge balance. The relations between the luminescence properties, crystal structures and the microstructures were well established. Results indicated that MgO promoted the densification of the ceramics as the specimens’ relative densities were up to 99%. Moreover, the substitution of Al³⁺ with Mg²⁺ have changed crystal structures and further affected the luminescent properties. Overall, the obtained ceramic phosphors showed strong red-light emission under excitation of ultraviolet and blue light. By optimizing the Mg²⁺ and Mn⁴⁺ concentration, a quantum efficiency (QE) as high as 47.8% can be achieved under the excitation of 460 nm light, indicating that the LuAG: Mn⁴⁺ ceramic phosphors are promising candidates for WLEDs applications.