Unravelling the process of energy transfer and color tuning from warm to cool white light emission in (Tb3+/Sm3+): lithium borate glasses

A set of individually and co-doped (Tb3+ + Sm3+): lithium borate glasses were synthesized by melt quenching. Photoluminescence properties were analyzed by excitation, emission, and decay dynamics. 1.5 mol% Sm3+ glass displayed an intense orange emission at 603 nm ((4)G(5/2) -> H-6(7/2)) under 403 nm excitation. Interestingly, Sm3+ emission was remarkably embellished by the indusion of Tb3+ ions owing to energy transfer from Tb3+ to Sm3+. Chromaticity coordinates and correlated color temperatures were tuned from a warm orange to a cool white region in Sm3+ and (Tb3+ + Sm3+): glasses, respectively. These studies suggest that (Tb3+ + Sm3+): lithium borate glasses are favorable candidates for white light emitting diode applications. (C) 2019 Optical Society of America