Improving the quality of red light emitting from Eu3+ by Co-doping Tb3+ in LuBa3(BO3)3

The red light emitting from phosphors activated with Eu3+ is of great significance for optimizing the comprehensive performances of white light-emitting diodes (WLEDs) for solid-state lighting. Herein, LuBa3(BO3)3:Eu3+ and LuBa3(BO3)3:Tb3+,Eu3+ phosphors are synthesized via the high temperature solid-state reaction to investigate the effects of the doping concentration of Eu3+ and the co-doping of Tb3+ on the quality of red emission from Eu3+ in the host. Under the excitation of 392 nm light, the dominant emission peak of LuBa3(BO3)3:xEu3+ gradually shifts from 593 nm to 610 nm when the doping concentration of Eu3+ is increased from 0.02 to 0.10, and the quality of red light emitting from Eu3+ in the host is found to be further improved with increasing the co-doping concentration of Tb3+, both of which are explained with the Judd-Ofelt theory. The calculated results indicate that the enhancement of red emission is attributed to the decrease of the environment symmetry of Eu3+ by increasing the concentration of Eu3+ in LuBa3(BO3)3:Eu3+ or co-doping Tb3+ ions. The color purity of the emission from LuBa3(BO3)3:0.10 Tb3+,0.10Eu3+ is 94.11%, and the luminescent intensity of the phosphor at 425 K is 69% of that at room temperature. Moreover, a WLED device with the high color rendering index of 91.1 is obtained by fabricating LuBa3(BO3)3:0.10 Tb3+,0.10Eu3+ and other phosphors with a 365 nm LED chip. The good comprehensive performances suggest that LuBa3(BO3)3:Tb3+,Eu3+ has a great application prospect as a red phosphor in the field of high-quality solid lighting. •The quality of red light emitting from Eu3+ in LuBa3(BO3)3 can be improved by increasing the concentration of Eu3+ or co-doping Tb3+.•The calculation results based on the Judd-Ofelt theory indicate that the symmetry of Eu3+ surroundings can be decreased by co-doping Tb3+ into LuBa3(BO3)3:Eu3+.•The Ra value of the WLED fabricated with LuBa3(BO3)3:0.10 Tb3+,0.10Eu3+ is as high as 91.1.