Combinatorial approach to the development of a single mass YVO₄: Bi³⁺,Eu³⁺ Phosphor with red and green dual colors for high color rendering white light-emitting diodes

Instead of developing a novel red phosphor individually, this work proposes the production of white light by combining a near-ultraviolet/ultraviolet diode chip with blue and special yellow phosphors: the yellow phosphor includes the red and green components with high color saturation. The availability of this scheme is demonstrated by preparing a white light-emitting diode (WLED) with color rendering index (Ra) up to 90.3. The desired single-mass yellow phosphor is successfully screened out from the YVO₄:Bi³⁺,Eu ³⁺ system by using a combinatorial chemistry approach. When the emission color and luminous efficiency are both considered, the best composition for producing white light is (Y_1-s-tBi_sEu _t)VO₄ with 0.040 ≤ s ≤ 0.050 and 0 < t ≤ 0.015. The red component that is required for a high-Ra WLED is obtained through sensitizing luminescence of Eu³⁺ by Bi³⁺ in a YVO ₄ host; meanwhile, both Bi³⁺ and Eu³⁺ emission are improved by keeping the Bi³⁺ and Eu³⁺ contents close to the critical concentration.