Ba₃Lu(BO₃)₃:Ce³⁺,Tb³⁺/Mn²⁺: Dual-Functional Material for WLEDs and Optical Pressure Sensing

Ba₃Lu(BO₃)₃(BLB):Ce³⁺,Tb³⁺/Mn²⁺ phosphors were designed to explore effective and multifunctional applications. Under the excitation of near-ultraviolet (n-UV) light, the BLB:Ce³⁺ phosphor showed broad-band blue emission. After codoping with Mn²⁺ ions, the single-phase white light phosphor is achieved through the energy transfer (ET) between Ce³⁺ and Mn²⁺. In addition, thermal stability is significantly enhanced by the addition of Tb³⁺ (BLB:0.02Ce³⁺,0.20Tb³⁺) compared to that codoped with Mn²⁺ (BLB:0.02Ce³⁺,0.10Mn²⁺). The light-emitting diode (LED) device with warm white light emission is fabricated with UV-chip-coated BLB:0.02Ce³⁺,0.05Tb³⁺ and Sr₂Si₅N₈:Eu²⁺ phosphors, showing a good potential application value for LEDs. Additionally, the spectral properties of borate-based phosphors (BLB:0.02Ce³⁺) under high pressure were studied for the first time. Surprisingly, the change of pressure enabled the emission peak of BLB:0.02Ce³⁺ to be tuned from 485 to 552 nm, and dλ/dP is 3.51 nm GPa^-1. The color changes from blue to yellow with an increase of pressure. Compared with the reported data, the pressure-sensing sensitivity based on the central peak shift in this work is the highest in all Ce³⁺ single-doped samples. In addition, the emitting color and intensity were gradually regained after decompression. The intensity can reach 80% of the initial intensity. All data demonstrate that the BLB:0.02Ce³⁺ phosphor has the potential to be utilized as an optical pressure sensor due to the high-pressure sensitivity and visible color tuning.