Concentration effect on the structural and spectroscopic investigations of Sm3+ ions doped B2O3-Bi2O3-CaF2-Na2O glasses

A new series of Sm3+ ions doped sodium fluoroborate glasses have been synthesized following the melt quenching technique. The structural analyses were made recording XRD and FTIR spectra. The XRD pattern reveals the amorphous nature and the FTIR spectra explore the presence of various functional groups such as B-O asymmetric stretching of trigonal BO3 units, B-O stretching of tetrahedral BO4 units and vibrations of Bi-O- bond in the BiO6 octahedral units. The luminescence properties have been explored through UV-vis-NIR, luminescence and decay spectral measurements. The Judd-Ofelt intensity parameters (Omega(2), Omega(4), Omega(6)) were determined from the absorption spectra to investigate the nature of metal-ligand bond and symmetry around the Sm3+ ion site. In order to elucidate the potential applications of the present Sm3+ ions doped glasses the radiative properties such as transition probability (A), effective band width (Delta lambda(eff)), stimulated emission cross-section (sigma(E)(p)) and branching ratio (beta R) for the (4)G(5/2) -> H-6(5/2), H-6(7/2), H-6(9/2) emission levels were determined and compared with the reported literature. The luminescence quenching for the prominent (4)G(5/2) -> H-6(7/2) emission transition have been observed while increasing the Sm3+ ions concentration beyond 0.5 wt%. The decay rates for the (4)G(5/2) level of the Sm3+ ions exhibit non-exponential behavior for all the prepared glasses except for the 0.05 wt% Sm3+ glass and fitted to Inokuti-Hirayama model to understand the predominant energy transfer mechanism takes place among the Sm3+ ions. It is observed from the determined stimulated emission cross-section and branching ratio values that, of all the studied glasses CNFB0.5S glass can be used as a potential candidate for the development of reddish-orange lasers.