Synthesis and Luminescence Properties of Pr³⁺-Doped BiPO₄ Polycrystals

The results of synthesis, crystal structure characterization and luminescence properties study of the Pr³⁺-doped bismuth orthophosphate, BiPO₄, polycrystals are reported. It was found that doping of bismuth orthophosphate with praseodymium of concentration more than 1% leads to phase transition of BiPO₄ from so-called "high-temperature monoclinic" to "low-temperature monoclinic" structure. At room temperature studied samples revealed intensive red luminescence caused by radiation electronic transitions in the Pr³⁺ ions under their intrinsic f → f excitation at ³H₄→ ³P₁+¹I₆ absorption transition. Influence of phase transformation as well as multi-phonon and cross-relaxation processes on the luminescence of the Pr³⁺-doped BiPO₄ compounds were discussed.