Energy transfer and color tuning of Dy ³⁺ /Sm ³⁺ co-doped tungsten borates for W-LEDs

Gd3BWO9: Dy3+, Sm3+ phosphors were synthesized via a high-temperature solid-state method and characterized by XRD, SEM, and PL. Under 364 nm excitation, the phosphors exhibited emission peaks at 485, 578, 599, and 645 nm, corresponding to the 4f-4f transitions of Dy3+ and Sm3+. As Sm3+ concentration increased, Dy3+ emission gradually decreased, while Sm3+ emission initially increased, peaked at y = 0.03, then decreased due to concentration quenching, primarily governed by electric quadrupole–quadrupole interactions. The optimal composition, Gd2.89BWO9: 0.08Dy3+, 0.03Sm3+, exhibited excellent thermal stability, retaining 83.38% of its initial intensity at 423 K. When fabricated into LED devices, it produced bright warm white light with a correlated color temperature of 2716 K. These results demonstrate that Gd3BWO9: Dy3+, Sm3+ is a promising luminescent material for warm-white LED applications.