Photoluminescence properties of Pr doped and Tb–Mg codoped CaSnO3 with perovskite structure

In the survey of photoluminescence properties of rare-earth doped alkaline-earth stannates, CaSnO3 was found to show intense white luminescence by Pr doping and green luminescence by Tb–Mg codoping. Pr doped CaSnO3 showed not only a red emission line originating from the f–f transition from 1D2 to 3H4 state, which is observed in Pr doped CaTiO3 or SrTiO3, but also an intense blue–green line assignable to the f–f transition from 3P0 to 3H4 state in Pr3+ ions. Because of the mixture of the red and blue–green luminescence, the Pr doped CaSnO3 was seen in white under uv excitation. Tb–Mg codoped CaSnO3 showed a sharp green emission line derived from the f–f transition of from 5D4 to 7F5 state in Tb3+ ions along with other small emission lines. Tb–Mg codoping effectively enhanced the green luminescence of Tb3+ ions probably due to the local lattice distortion around Tb ions induced by the small Mg ions at Ca sites. The photoluminescence properties of Pr doped and Tb–Mg codoped ASnO3 (A = Sr, Ba) and CaMO3 (M = Ti, Zr) with perovskite structures were also examined and compared to understand the luminescence mechanisms in these materials.