Enhancing Emission Property of Red Phosphor Sr2MgGe2O7:Mn4+ Via Ba2+ Doping

A series of non-rare-earth red-emitting phosphors, Sr2−xBaxMgGe2O7:Mn4+, are prepared. Compared to the parent phosphor of Sr2MgGe2O7:Mn4+, the Ba2+-doped phosphors show unchanged crystal structure with slightly lattice distortion, which results in very similar excitation/emission spectra and thermal stability in emission, accompanying with increased luminescence and longer emission lifetime. The optimized phosphor exhibits emission quantum yield of 88%, decay lifetime of 3.59 ms and emission peak of 664 nm originating from the 2E → 4A2 spin- and parity-forbidden transition of Mn4+. At high temperature of 423 K, the emission intensity is still 94.3% of that at room temperature, showing excellent thermal stability of emission.