Preparation and optical characterization of Eu3+-doped CaTiO3 perovskite powders

Abstract

CaTiO3 perovskite powders doped with 1.0, 1.5, 2.0, 2.5, 3.0, and 5.0mol% Eu3+ were prepared by sol–gel technique followed by annealing at high temperatures. The powders were characterized by X-ray diffraction, scanning electron microscopy, Raman scattering, absorption, and photoluminescence spectroscopy. The obtained powders possessed orthorhombic crystal structure. Raman spectra of the CaTiO3:Eu3+ powders exhibited seven new peaks at 798, 1048, 1188, 1371, 1441, 1601, and 1644cm−1 which were assigned to the localized vibrational modes related to the complexes containing Eu3+. It was found that the band edge of the material shifted to the higher-energy side with increasing Eu3+-impurity content. The photoluminescence of Eu3+ ions results from the radiative intra-configurational f–f transitions that happen between the 5DJ (J=0, 1–3) exited states and the 7FJ (J=0,1–4) ground states; the photoluminescence excitation of Eu3+ ions takes place from the 7F0 ground state to the 5DJ (J=1–4), 5L6, and 5G2,6 exited states.