A novel borate phosphor Lu 5 Ba 6 B 9 O 27 :Ce 3+ codoped with Sr 2+ /Tb 3+ for NUV-white light emitting diode application.

At present, there are still challenges in developing highly efficient and thermally stable phosphors for ultraviolet/near ultraviolet-white light emitting diodes (UV/NUV-WLEDs). Herein, we use traditional high-temperature solid-state reactions to prepare blue-emitting phosphors Lu 5- x Ba 6 B 9 O 27 : x Ce 3+ (0.1% ≤ x ≤ 3.0%) and Lu 4.975 Ba 6- y Sr y B 9 O 27 :0.5%Ce 3+ (0% ≤ y ≤ 20%), and green-emitting phosphors Lu 4.975- z Ba 6 B 9 O 27 :0.5%Ce 3+ , z Tb 3+ (0% ≤ z ≤ 16%), abbreviated as LBB: x Ce 3+ , LBB:0.5%Ce 3+ , y Sr 2+ and LBB:0.5%Ce 3+ , z Tb 3+ , respectively. Upon 340 nm excitation, LBB:Ce 3+ exhibits an asymmetric blue emission ranging from 360 nm to 480 nm. Furthermore, the emission intensity of LBB:0.5%Ce 3+ increased 4.8-fold without a spectral shift through the partial substitution of Sr 2+ for Ba 2+ . Through constructing the Ce 3+ → Tb 3+ energy transfer in the LBB structure, the temperature-dependent integral emission intensity at 483 K improved from only 25% to 68% of the intensity at 303 K due to the existence of fast energy transfer from Ce 3+ to Tb 3+ . The related results indicate that LBB: x Ce 3+ , LBB:0.5%Ce 3+ , y Sr 2+ and LBB:0.5%Ce 3+ , z Tb 3+ phosphors can be used for UV/NUV-WLEDs.