Structural Confinement toward Giant Enhancement of Red Emission in Mn2+-Based Phosphors

Structural confinement effect on a pair of Eu2+ and Mn2+ optical centers is developed to realize the greatly enhanced red emission attributed to the T-4(1)((4)G)-(6)A(1)(S-6) transition of Mn2+ ions. Sr9Mn1.26(2)Li0.24(2)(PO4-delta)(7) , when it is doped with Eu2+, emerges as a new red-emitting phosphor, and the intensity dependence of such a red emission on the trace amounts of Eu2+ doping is quantitatively analyzed with a combined experimental and theoretical methods. The modeling result confirms the validity of this proposed design strategy, and the intrinsic high-efficient Eu2+-Mn2+ energy transfer process can be elucidated by the structural confinement effect featured as some Sr (Eu) close to Mn atoms. The results can initiate the exploration of Mn2+-based red phosphors for pc-white light-emitting diodes applications, and such a strategy can be easily expanded to other systems, thus opening a new perspective for the development of luminescence materials.