Fluorescence decay dynamics and anneal effect on praseodymium ions doped in lead tungstate single crystal

Fluorescence decay dynamics of main emission manifolds of trivalent praseodymium ions doped in the as-grown and annealed PbWO4 crystals were analyzed in detail. The fluorescence lifetimes of the 3P0 and 1D2 manifolds were obtained from the fluorescence decay curves measured at room temperature. The main mechanism of fluorescence quenching of the 3P0 manifold is the non-radiative relaxation to the defect centers coming into being during crystal growth. The dominant non-radiative relaxation for the 1D2 manifold is the cross-relaxation energy transfer involving the 1G4 and 3F4 manifolds. The Inokuti–Hirayama model was used to analyze the decay dynamics of the 1D2 manifold, and the fluorescence lifetime τ0 of the as-grown and annealed Pr3+:PbWO4 crystals in absence of cross-relaxation energy transfer are derived as 35.2 μs and 37.9 μs, respectively. The annealing treatment can eliminate most defect centers except for those related to the lead vacancies.