Optical response and luminescence characteristics of Sm 3+ and Tb 3+ /sm 3+ co-doped potassium-fluoro-phosphate glasses for reddish-orange lighting applications

Abstract Potassium-fluoro-phosphate (KFP) glasses singly doped with different concentrations of samarium (0.1, 0.3, 0.5, 1.0, 1.5 and 2.0 mol%) and co-doped with Tb 3+ (0.1, 0.5, 1.0 mol%) were prepared, and their luminescence properties were investigated. Optical transition properties of Sm 3+ ions were evaluated by using Judd–Ofelt theory. Various emission properties were studied from luminescence spectra. Reddish-orange emission of Sm 3+ exhibits mainly by 4 G 5/2 level to 6 H 7/2 located at 600 nm. Concentration quenching and energy transfer were observed from fluorescence spectra and decay curves respectively. The non-exponential decay profiles were analyzed Inokuti–Hirayama model (I–H). From this model, various energy transfer kinetic parameters were also calculated and analyzed. By co-doping with Tb 3+ , energy transfer from Tb 3+ to Sm 3+ takes place and contributes to enhancement in emission intensity and intense reddish-orange emission was obtained. The optimized properties of the Tb 3+ /Sm 3+ co-doped KFP glasses indicate that these glasses can be used as luminescent materials.