Effects of compositional phase transitions on luminescence of Sr1−xCaxTiO3:Pr3+

The mixed-compound of Sr1−xCaxTiO3 has shown several compositional phase transformations. Photoluminescence and excitation spectra of the samples with different x and doped with 0.2% Pr3+ were investigated. Changes in the emission spectra were observed in different phases. The blue emission at 491 nm from 3P0 state was found quite strong in the tetragonal phase, and was thermally quenched in the orthorhombic phases. The intensity of the red luminescence from 1D2 increases with increasing content of calcium. The strongest red emission is obtained from CaTiO3:Pr3+. The results are discussed based on the configuration coordinate model and interaction of Pr with the charge transfer exciton state of the Ti complex.