Fluorescence spectroscopy of Sm3+ ions in P2O5–PbO–Nb2O5 glasses

Sm3+-doped lead phosphate-based glasses modified with niobium have been prepared and characterized by optical absorption, emission spectra and decay curve analysis. The peak positions and intensities of the absorption spectrum of 1.0 mol% Sm2O3-doped glass have been analysed by the free-ion Hamiltonian model and Judd–Ofelt analysis, respectively. The predicted radiative properties are comparable with the experimental values. The emission properties and lifetimes of the 4G5/2 level for different Sm3+ ion concentrations have been determined. Lifetime of the 4G5/2 level decreases, with increase of Sm3+ ions concentration, from 2.52 (0.1 mol%) to 0.57 ms (4.0 mol%) due to cross-relaxation energy transfer (ET) between Sm3+ ions. The decay curve for the 4G5/2 level is single exponential for 0.1 mol% Sm2O3 ions concentration and become non-exponential from 0.5 mol%. The non-exponential decay curves are well fitted to the Yokoto–Tanimoto model. From decay curve analyses, ET, donor to acceptor interaction and diffusion parameters have been obtained and their relative variation with concentration of Sm3+ ions has been discussed. The calculated relative donor quantum yield also supports ET between Sm3+ ions.