White light-emitting diodes provide
widespread applications in
lighting, electronic equipment, and high-tech displays. However, thermal
quenching effect severely limits their practical application. Here,
we developed an orange-red phosphor β-KMg(PO3)3:Mn2+, which emits bright orange-red light when
excited by ultraviolet light without the energy transfer of sensitizer,
owing to the strong crystal field provided by β-KMg(PO3)3 for Mn2+. The self-reduction of Mn4+ → Mn2+ and good thermal stability have been realized
in an ambient atmosphere. The defect types were verified by X-ray
photoelectron spectroscopy, and cationic vacancy plays a significant
role in the self-reduction of Mn4+ → Mn2+. Furthermore, the properties of the trap energy levels were studied
by thermoluminescence. The recombination luminescence of the detrapped
carriers released from the deep trap levels at high temperatures suppresses
the luminescence loss of thermal quenching. Moreover, the trap energy
levels play an important role in the mechanoluminescence of β-KMg(PO3)3:Mn2+. This work emphasizes the significance
of the defects in the luminescent characteristics and opens up a new
approach for the development of advanced optical functional materials.