Multicolor and white light emitting Tb3+/Sm3+ co-doped zinc phosphate barium titanate glasses via energy transfer for optoelectronic device applications

A series of Tb3+/Sm3+ co-doped ZPBT glasses have been successfully prepared via melt quenching technique and their photoluminescence properties and energy transfer mechanism were investigated. Tb3+ doped glass exhibits dominant emission peak at 544 nm corresponding to 5D4→7F5 transition under 375 nm excitation whereas Sm3+ doped glass exhibits intense emission peak at 599 nm corresponding to 4G5/2 → 6H7/2 under 399 nm excitation. The CIE chromaticity coordinates (0.259, 0.590) and (0.570, 0.428) are located in the pure green and orange region for Tb3+ and Sm3+ doped glasses, respectively. The Tb3+/Sm3+ co-doped glasses under 375 nm excitation emit a combination of blue, green and orange-red light while under 484 nm excitation emits green and red-orange emission light. The energy transfer occurs from Tb3+ to Sm3+ via dipole-dipole interaction, which was confirmed by applying Dexter and Reisfeld's theory and Inokuti Hirayama (I-H) model. Moreover, the energy transfer efficiencies and probabilities were calculated from the decay curves. The color tone of these glasses can be modulated from yellowish-green to warm-white via greenish-yellow by appropriate tuning of Sm3+ concentrations and excitation wavelengths. These results indicate that the prepared glasses can be a potential candidate for white light as well as solid state lighting applications.