Abstract: Addressing the urgent demand for high color rendering index and low color temperature single-phase phosphor for near-ultraviolet-excited white light emitting diode （WLED）， this study proposed a novel color-tunable phosphor system based on MgY₂Si₃O₁₀ host co-doped with Bi³⁺and Eu³⁺. A series of MgY₂Si₃O₁₀∶0.02Bi³⁺， mEu³⁺ （m=0~0.22） samples were successfully synthesized via the high-temperature solid-state method. Their phase structure and luminescence properties were systematically characterized. The results indicate that Bi³⁺ occupies two distinct crystallographic sites in the host lattice， exhibiting a dual-peak broad-band emission under 344 nm excitation， while Eu³⁺ displays characteristic red emission. Through spectral overlap analysis and fluorescence lifetime test， it is confirmed that there is efficient energy transfer （ET） from Bi³⁺ to Eu³⁺， with its efficiency increasing with Eu³⁺ doping concentration and reaching a maximum of approximately 65%. The critical energy transfer distance （R_C） is calculated to be about 13.2 ? based on the concentration quenching model and the primary ET mechanism is electric dipole-electric quadrupole （d-q） interaction. By adjusting the Eu³⁺ doping concentration， continuous tuning of the emission color is successfully achieved， ranging from blue through white to red. The white emission exhibits chromaticity coordinates of （0.333，0.306）， a correlated color temperature （CCT） of 5 419 K， a general color rendering index （R_a） of approximately 85.6， as well as good thermal stability. This study provides systematic experimental and theoretical foundations for the development of high-performance， color-tunable phosphor materials for WLED applications.

Key words: WLED; Bi³⁺ and Eu³⁺ co-doping; high-temperature solid-state method; energy transfer; color tunability; thermal stability