Intense Luminescence and Good Thermal Stability in a Mn2+- Activated Mg-Based Phosphor with Self-Reduction br

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 beta-KMg(PO3)3:Mn2+, which emitsbright orange-red light when excited by ultraviolet light without theenergy transfer of sensitizer, owing to the strong crystalfield provided by beta-KMg(PO3)3for Mn2+. The self-reduction of Mn4+-> Mn2+and goodthermal stability have been realized in an ambient atmosphere. The defecttypes were verified by X-ray photoelectron spectroscopy, and cationicvacancy plays a significant role in the self-reduction of Mn4+-> Mn2+.Furthermore, the properties of the trap energy levels were studied bythermoluminescence. The recombination luminescence of the detrappedcarriers released from the deep trap levels at high temperatures suppressesthe luminescence loss of thermal quenching. Moreover, the trap energylevels play an important role in the mechanoluminescence of beta-KMg(PO3)3:Mn2+. This work emphasizes the significance of thedefects in the luminescent characteristics and opens up a new approach for the development of advanced optical functional materials