Site occupancy and phonon sideband of trivalent europium doped calcium aluminosilicate phosphors

A series of Eu3+ doped Ca2Al2SiO7 were synthesized by the solid-state reaction method. Structural and luminescent properties of the obtained samples were investigated through X-ray diffraction, Raman and luminescence spectra. The luminescent characteristic of the 5D0 → 7F0,1 transitions from emission spectra of Eu3+ ions showed that the Eu3+ ions occupy at two different sites in Ca2Al2SiO7 lattice. The Ca2Al2SiO7:Eu3+ red phosphors have three phonon sidebands with energies ~673 cm−1, 848 cm−1 and 1443 cm−1 which have been determined via the excitation spectra of Eu3+ ions in Ca2Al2SiO7 materials. These obtained phonon energies coincided with the vibrational energies observed from Raman spectra. The multiphonon relaxation rates for the excited levels of 5D1, 5D2 and 5D3 of Eu3+ ions in Ca2Al2SiO7 were also calculated.