Realization of narrow-band blue emission based on structurally engineering-designed Bi3+-doped phosphors

The exploration of efficient narrowband emission phosphors is crucial for white light-emitting diodes (WLEDs) in high-performance backlighting applications. Up to now, the discovery of narrow-band Bi³⁺-doped phosphors for emerging applications remains challenging because Bi³⁺ typically exhibits broadband emission properties. A novel narrow-band blue phosphor (Ca₄SnGe₃O₁₂:Bi³⁺) was successfully synthesized, benefiting from the highly symmetric crystal environment and tightly connected rigid structure of the garnet structure. The phosphor demonstrates broad excitation in the near-ultraviolet (n-UV) region and emits narrowband blue light at 442 nm (FWHM = 36 nm) with a color purity of 94.7 %. In this paper, the assignment of different luminescence centers and the use of Zr/Hf to partially replace Sn to enhance luminescence performance are studied. The reasons for the consequent changes in luminescence behavior are explained in detail. The use of narrowband commercial red K₂SiF₆:Mn⁴⁺, green β-Sialon:Eu²⁺, and synthetic blue luminescent materials as RGB emitters covered 81 % of the National Television System Committee (NTSC) color space, demonstrating great potential for liquid-crystal-display (LCD) backlight use.