Achievement of narrow-band blue-emitting phosphors KScSr1−yCaySi2O7:Bi3+ by the migration of luminescence centers

Abstract

In recent years, efforts have been made to develop narrow-band emission phosphors with excellent performance. Herein, a series of KScSr_1−yCa_ySi₂O₇:0.07Bi³⁺ narrow-band phosphors were synthesized by a co-substitution method, and the crystal structure, the occupancy of activated ions and luminescence properties were studied in detail. The substitution of Ca²⁺ for Sr²⁺ ions resulted in the migration of the activated Bi³⁺ from the K site to Sr site, accompanied by the regulation of the emission peak from 410 nm to 455 nm, the peak emission half width from 52 nm to 40 nm, and the color purity from the original 78% to 88%. In addition, a warm white LED with low CCT = 3401 K, CRI = 95.5, and CIE color coordinates of (0.3447, 0.3682) has been obtained through the combination of KSS_0.6C_0.4S:0.07Bi³⁺ with a commercial green and red phosphor on a UV (370 nm) chip. The results not only provided a strategy based on the manipulation of chemical composition and crystal structure to tune spectral distribution, but also broadens the choice of activators of narrow-band blue-emitting phosphors.