Enhanced thermal stability and energy transfer in Mn2+ co-doped MgAl2O4:Cr3+ for potential applications

Deep-red light emitting phosphors have become a research hotspot due to their pivotal roles in plant growth and high color rendering full-spectrum white lighting fields. Herein, Mn²⁺ and Cr³⁺ doped MgAl₂O₄ phosphors were prepared by a high-temperature solid-state method in a thermal carbon reducing atmosphere, the green (Mn²⁺) and deep-red (Cr³⁺) luminescence properties were investigated, respectively. The concentration-dependent and temperature-dependent luminescence properties were discussed in detail. Energy transfer from Mn²⁺ to Cr³⁺ was demonstrated in Mn²⁺ and Cr³⁺ co-doped samples. Enhanced thermal stability and dual-excitation wavelength response of MgAl₂O₄:Cr³⁺ were achieved via co-doping with Mn²⁺. At 425 K, the integrated emission intensity of Cr³⁺ maintains 95.5 % in comparison with that at 300 K for MgAl₂O₄:0.03Mn²⁺,0.005Cr³⁺ under 400 nm excitation. Thanks to the superior deep-red luminescence properties of MgAl₂O₄:Mn²⁺,Cr³⁺, the potential applications in plant-growth lighting and high-quality warm white illumination were demonstrated.