Disorder Engineering of Spinel Structure Synergistically Enhances Luminescence and Afterglow Emission of Mn2+ for Multifunctional Optoelectronic Applications.

Long-afterglow phosphors have garnered significant attention in optical storage due to their persistent luminescence arising from intrinsic atomic defects. However, introducing additional defect states to enhance afterglow intensity while maintaining satisfactory luminescence emission remains a major challenge, let alone understanding the correlation between structural defects and luminescence/afterglow performance. This study successfully demonstrates that Mg2+ doping effectively induces structural disorder in LiGa5O8:Mn2+ (LGO:Mn2+) spinel, simultaneously enhancing its photoluminescence and long afterglow emission performances. The experimental and theoretical calculation results indicate that a higher Mg2+ doping ratio promotes spinel structural disorder and local lattice distortion. Specifically, the hybridization between Mg2+ (3s/3p) and O2- (2p) orbitals enhances energy transfer efficiency to Mn2+ activators while suppressing concentration quenching effects. Furthermore, the local lattice distortion accelerates oxygen vacancy formation, introducing more active sites capable of capturing electrons and increasing the "charge capacity." Demonstrating remarkable luminescence and afterglow emission properties, the synthesized LGO:Mn2+, Mg2+ phosphor successfully extends its application to optical information storage and magnesium-bearing ore detection. The disorder engineering strategy proposed herein provides profound insights into the structure-optical property relationship of spinel phosphors, offering novel concepts and approaches for designing advanced luminescent materials suitable for multifunctional optoelectronic applications.