White light emission regulation of Eu2+/Bi3+/Sm3+ Co-doped Ca4MgAl2Si3O14 phosphors under near-ultraviolet excitation

Abstract

For the attainment of healthy and comfortable full-spectrum lighting, it is of great importance to develop white phosphors that can be excited by near-ultraviolet (n-UV) light. Herein, we report a single-matrix white-emitting phosphor, Ca₄MgAl₂Si₃O₁₄: Eu²⁺, Bi³⁺, Sm³⁺ (CMAS: Eu²⁺, Bi³⁺, Sm³⁺). When excited by 300 nm light, the CMAS: Eu²⁺ phosphor emits yellow-green light peaking at 530 nm, while the CMAS: Bi³⁺ phosphor produces blue emission centered at 400 nm. Through energy transfer between Bi³⁺ and Sm³⁺, dual emission bands at blue and red regions are achieved, which complements the emission spectrum of Eu²⁺ and makes it possible for a single CMAS matrix to emit white light. The photoluminescence intensity and thermal stability of CMAS: Eu²⁺ at 423 K are improved via Na⁺ substitution for Ca²⁺ due to the reduction of Eu³⁺ to Eu²⁺ and the elevated activation energy barrier inhibit thermal quenching at elevated temperatures. The white LED lamp, fabricated with a 300 nm LED chip and synthesized CMAS: Eu²⁺, Na⁺, Bi³⁺, Sm³⁺ phosphor, demonstrates good color quality. This indicates its promising potential for applications in healthy solid-state lighting.