Scintillator materials based on the Ce-doping are of persistent interest due to tens-of-ns range decay time depending on the crystal host. Doping PrF₃ with Ce³⁺ was shown to be a novel approach to obtain promising scintillators because of efficient energy transfer from the Pr³⁺ subsystem to Ce³⁺-ions via the ¹S₀ level of Pr³⁺ [1]. Successful crystal growth of PrAlO₃ and results of spectroscopic properties characterization were reported recently [2]. Undoped PrAlO₃ hardly ever could be used as a scintillator because of strong concentration quenching of the Pr³⁺ 5d-4f emission. However, it also points to an enhanced energy migration over the Pr³⁺-energy levels. On the other hand, a recent study has demonstrated facilitating energy transfer from the Gd³⁺ sublattice to Ce³⁺ emission centers by formation of the Ce³⁺-distorted centers in YF₃-GdF₃ solid solutions codoped with Me²⁺ ions such as Sr²⁺ [3].

To investigate this phenomenon, Ce (1, 2 and 5 mol%)-doped PrAlO₃, and Ce (5 mol%), Sr (0.1, 0.5 and 1 mol%)-codoped PrAlO₃ single crystals were grown by the micro-pulling-down method. Using the UV and X-ray excitation their luminescence spectra and decay kinetics were investigated. Under X-ray excitation in the undoped PrAlO₃ a weak 5d-4f Pr³⁺ emission occurs within 250-300 nm at room temperature, which is well overlapped with the excitation spectra of Ce³⁺ emission in YAlO₃ host. In such circumstances an efficient energy transfer from the Pr-sublattice to the Ce³⁺ ions might occur in Ce-doped PrAlO₃. Obtained results will be presented and discussed in the light of the (Pr³⁺)_n→Ce³⁺ energy transfer characteristics and potential of such a material to obtain a fast scintillator of elevated density.

[1] M. Nikl et al., phys. stat. sol. (a) 201 (2004) R108.

[2] D.A. Pawlak et al., J. Cryst. Growth 282 (2005) 260.

[3] M. Nikl et al., J. Phys.: Condens. Matter 18 (2006) 3069-3079.