Structural and optical properties of Mg1−xMnxP2O6(x = 0–1.0) magnesium metaphosphate

Abstract

AbstractStructural and optical properties of Mg1−xMnxP2O6(x = 0–1.0) magnesium metaphosphate were investigated in detail. The complete solid solution of MgP2O6–MnP2O6is confirmed as monoclinic space groupC2/c. The dynamic luminescence was studied by changing the Mn2+content (0–100 mol%) and temperature (10–300 K). There is a good chemical homogeneity in Mg1−xMnxP2O6(x = 0–1.0), which can be supported by the linearly varying cell size and the gradually changing vibration spectrum. However, the optical properties of the solid solution do not show a continuous change trend, that is, an obvious inflection point appeared whenx = 0.5. Mg1−xMnxP2O6(x = 0.1–0.5) shows a dominant O2− → Mn2+charge transfer (CT) absorption in the near UV region and feeble d–d transitions of Mn2+in visible wavelength region. However, Mg1−xMnxP2O6(x = 0.6–1.0) presents a strong d–d absorption transition and nearly disappeared CT band. The changing trend of optical absorption is also maintained in the excitation and emission of the solid solutions. In Mg1−xMnxP2O6(x = 0.1–0.5), (Mn, Mg)O6octahedron has slight distortion, and the effective luminescence only occurs when CT band excitation is used. In contrast, in Mg1−xMnxP2O6(x = 0.6–1.0), (Mn, Mg)O6octahedron is highly distorted, and only excitation at d–d transition produces effective luminescence. This research highlights the critical role of MnO6octahedral distortions in the luminescence properties of Mn2+activators. The research provides a reference for developing optical materials.