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

Abstract

Fluorescence decay dynamics of main emission manifolds of trivalent praseodymium ions doped in the as-grown and annealed PbWO 4 crystals were analyzed in detail. The fluorescence lifetimes of the 3P 0 and 1D 2 manifolds were obtained from the fluorescence decay curves measured at room temperature. The main mechanism of fluorescence quenching of the 3P 0 manifold is the non-radiative relaxation to the defect centers coming into being during crystal growth. The dominant non-radiative relaxation for the 1D 2 manifold is the cross-relaxation energy transfer involving the 1G 4 and 3F 4 manifolds. The Inokuti–Hirayama model was used to analyze the decay dynamics of the 1D 2 manifold, and the fluorescence lifetime τ 0 of the as-grown and annealed Pr 3+:PbWO 4 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.