Geometrical and Electronic Structure Analysis of Mn-Doped CaMO₃ (M = Ti, Zr, and Sn)

The geometrical and electronic structures of Mn-doped CaTiO₃, CaZrO₃, and CaSnO₃ deep-red emission phosphors are investigated both experimentally and theoretically. All the samples are synthesized with solid-state reaction method by changing the concentration of the doped Mn ions. Crystal structures of the fabricated samples are examined with the powder X-ray diffraction technique and valence states of the doped Mn ions are determined by measuring the Mn-L₃ X-ray absorption near-edge structure (XANES) spectra. Diffuse reflectance spectra are observed to study the change in electronic structures due to the Mn doping. First-principles calculations are also carried out to investigate geometrical and electronic structures of Mn-doped CaMO₃, in which different types of electron–electron correlation functionals are employed.