Achieving efficient violet-light-excited blue phosphors by nitridation for violet-chip-based full-spectrum lighting

Abstract

With the pursuit of healthy lighting, full-spectrum white light-emitting diodes (WLEDs) fabricated with violet chips and tri-color phosphors have been put forward. However, the excitation bands of most reported blue phosphors are located in the ultraviolet (UV) region, which hinders the development of full-spectrum lighting. In this work, by partially introducing N³⁻ into a matrix, a series of Ba_0.697Al_10.914O_17.232-3y/2N_y:0.16Eu²⁺ (BAON_y:Eu) blue phosphors with red-shifted photoluminescence excitation (PLE) spectra were synthesized. Under the excitation of 400 nm violet light, the internal/external quantum efficiency (IQE/EQE) values of the optimal sample BAON_1.0:Eu were calculated to be 80%/52%, while the retained integrated emission intensity at 150 °C can be 95% of that at room temperature. The WLED device fabricated by coating BAON_1.0:Eu and other commercial phosphors on a violet chip achieved an ultra-high color rendering index (R_a = 95.4). These results indicate that our synthesized BAON_1.0:Eu can be an excellent candidate blue phosphor for full-spectrum WLED lighting.