Isolated Coordination Polyhedron Confinement in ABP₂O₇:Mn²⁺ (A = Ba/Sr; B = Mg/Zn)

Many research efforts have focused on designing new inorganic phosphors to meet different application requirements. The structure-photoluminescence relationship between activator ions and the matrix lattice plays an irreparable role in designing target phosphors. Herein, a series of ABP₂O₇:Mn²⁺ (A = Ba/Sr; B = Mg/Zn) phosphors are prepared for a detailed study on the relationship between the luminescence performance and spatial structure and symmetry of the doping site of Mn²⁺. Due to the weak interaction between nearest B-B pairs, [BO₅] is defined as an isolated coordination polyhedron whose structure and symmetry directly influence the photoluminescence of Mn²⁺. The emission wavelength of Mn²⁺ is ∼620 nm when it occupies the triangular bipyramid [MgO₅] in BaMgP₂O₇. When Mn²⁺ occupies the quadrangular pyramid-typed [MgO₅] or [ZnO₅] in SrMgP₂O₇, SrZnP₂O₇, and BaZnP₂O₇, the emission wavelengths peak at ∼670 nm. We propose a conception of isolated coordination polyhedral confinement to clarify the luminescence performance of Mn²⁺ in the fivefold coordination configuration with different geometries, which has great theoretical research significance for designing inorganic phosphors.