A novel Tb3+ ions doped barium strontium fluorosilicate (Tb3+: BSFS) glasses for green laser emission and white LEDs

A novel Tb3+ ions doped barium strontium fluorosilicate (Tb3+: BSFS) glasses were synthesized with melt-quenching, of which chemical composition was (55-x) SiO2 + 10 BaCO3 + 10 SrCO3 + 15 CaF2 + 10 ZnO + x Tb4O7, x = 0.1, 0.5, 1.0 & 2.0 wt. %. And its structural, physical and optical properties were investigated. X-ray diffraction analysis confirmed that this Tb3+: BSFS was amorphous, a glass in nature. Its UV-vis-NIR absorption spectrum displayed six absorption peaks located at 2210, 1886, 485, 376, 367, and 349 nm, respectively, corresponding to the transitions from F-7(6) ground state to the various excited states. Its Judd-Ofelt parameters Omega(lambda)(lambda = 2, 4 and 6) were determined from the oscillator strength (f(exp)), and were used to evaluate the spectroscopic properties for the emissions of D-5(4)->(7)FJ (J = 3, 4, 5, 6) transitions. Its luminescence property was examined with the excitation spectrum under 543-nm light source and the emission spectrum under 378-nm light source. CIE chromaticity co-ordinates (x, y) and (u, v), correlated color temperature, and color purity were evaluated. Its radiative parameters, such as stimulated emission cross-section (sigma(E)(p)), branching ratios (beta(R)), quantum efficiency (eta) and gain bandwidth (sigma(E)(p) x Delta lambda(eff)), values were also calculated for D-5(4)->(7)FJ transitions. All the decay curves of D-5(4)->(7)FJ transitions exhibited single exponential nature. The resultant parameters were scrutinized and compared with previous reported Tb3+ doped glasses in order to examine the capability of this glass for green laser and visible sources and white emitting diodes (WLEDs) applications.