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 ⁴T₁(⁴G)–⁶A₁(⁶S) transition of Mn²⁺ ions. Sr₉Mn_1.26(2)Li_0.24(2)(PO_4−δ)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.