High-temperature preparation of a new Mn2+ phosphor in the open air with red emitting properties

There is a strong correlation between luminescent performance and Mn oxidation state for Mn-activated phosphors. In this study, Mn2+ doped LiMg3P3O11:Mn2+ (LMP:Mn2+) is synthesized by conventional high-temperature solid state reaction method under air environment in which the Mn dopants lie in low oxidizing degree of Mn2+. Upon excitation at 410 nm, the phosphor exhibited a strong red photoluminescence band centered at 620 nm, suggesting that Mn2+ occupy the six-coordinated Mg sites of LMP lattice. Combining luminescent performance with X-ray photoelectron spectroscopy (XPS) and Electron Paramagnetic Resonance (EPR) analysis, we think that the formation of Mg-vacancy is responsible for the stability of Mn2+ valance state. In addition to providing a new red phosphor, this study also provides new insights into Mn's valence control and luminescence tuning.