Bright green fluorescence from Tb3+ activated lithium zinc borate glasses for solid-state laser and w-LEDs applications

Abstract

Lithium zinc borate glasses (LBZ) composed of Li2CO3-LiF-H3BO3-ZnO activated with distinct concentrations (0.1–1.0 mol%) of Tb3+ ions were synthesized and explored their structural and optical characteristics. The functional groups and non-crystalline behavior of glasses were validated from the RAMAN and X-ray diffraction analysis, respectively. The optical bandgap was found to be 3.203 eV for (0.5 mol%) Tb3+ contained glass. The excitation spectrum of the same glass discloses a sharp peak at 376 nm (7F6→5D3). Under 376 nm excitation, luminescence spectra of Tb3+ ions incorporated glasses displayed the prominent emission transitions noticed at 5D4 → 7F6–3 with a strong green luminescence centered at 543 nm (5D4 → 7F5). The optimized concentration of Tb3+ for efficient green color emitting display devices was found to be 0.5 mol%. Lifetime decay analysis was carried out which is well fitted in single exponential function and it was found to be 1.032 ms. CIE color coordinates were estimated for all the procured glasses from their emission spectra and they are reside in the strong green color zone. The obtained green color coordinate values of the optimized glass were closer to the SMPTE and EBU coordinates (0.290, 0.600) for the green illumination appreciably. CCT values of the optimized Tb3+ incorporated glass were lie in the cool green region with high color purity of 82%. From these strong green emission features of the studied glasses, 0.5 mol% Tb3+: LBZ glassy matrix could be suggested as a potential candidate for the application of green laser and display device applications.