Cation substitution strategy realizing controllable spectral shape and multiple applications in a novel blue-cyan emitting KBaScSi2O7:Bi3+ phosphor

Controlling the emission spectrum shape and the site occupancy tendency are of great significance for designing full-visible-spectrum phosphors in pc-wLEDs application. Herein, a novel blue-cyan emitting KBaScSi₂O₇ (KBSS):Bi³⁺ phosphor is reported. Under excitation at 331 nm UV light, the KBSS:0.04Bi³⁺ exhibits a broadband blue-cyan emission, including a primary peak at 409 nm and a shoulder peak at 493 nm. The two emission peaks exhibit different thermal quenching behaviors because of the existence of defects. The implementation of Y³⁺, Lu³⁺ and Cs⁺ substitutions has successfully enhanced the luminescence intensity of the samples by factors of 1.4, 2, and 2.3, respectively, and the goal of controlling the spectral shape and site occupancy tendency is achieved. Their applications in luminescence thermometers and wLEDs are evaluated. The S_r (relative sensitivity) and S_a (absolute sensitivity) of phosphor are 0.37 % K^-1 and 0.20 % K^-1, respectively and the as-fabricated white LED device shows superior luminescence performance (CCT = 5311 K, Ra = 90).