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 (Y1-s-tBisEu 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.
ASJC Scopus subject areas