Thermal quenching of Mn⁴⁺ luminescence in SrAl₁₂O₁₉:Mn⁴⁺

Thermal quenching is a common phenomenon hindering commercial applications of phosphors, and the relationship between matrix structure and thermal quenching is not yet clear especially for the red phosphor SrAl₁₂O₁₉:Mn⁴⁺. Here, we determined the energy levels of three types of Mn⁴⁺ sites in SrAl₁₂O₁₉ crystal structure based on the exchange-charge-model crystal field calculations and analyzed the Mn⁴⁺ ions preferential occupation combined with chemical bond covalence. The phosphor suffers from serious thermal quenching when the luminescence monitoring from 8 to 500 K was recorded. The combination of theoretical calculations and experimental verification also reveals that the symmetry and spatial distribution of octahedral sites for Mn⁴⁺ are crucial to better resistance to thermal quenching. This can be helpful to search for novel Mn⁴⁺ doped red phosphor with better resistance to thermal impact in the future.