A near UV-excited abnormal broad yellow emission phosphor Ba2CaB2Si4O14:Eu2+ for white-light LEDs

Highlights: • Ba₂CaB₂Si₄O₁₄:Eu²⁺ has a wide coverage and is in the abnormal red light region. • In combination with blue phosphor, it improves the quality of synthetic white light to a certain extent. • It has great potential in the preparation of near UV excited white LEDs. -- Abstract: Phosphor-converted white LEDs are realized by combining blue InGaN chips with yellow and red emitting materials. Due to the lack of efficient red phosphor materials, we can design a broadband yellow phosphor material containing as many red components as possible. We found an abnormal broadband yellow-emitting Ba₂CaB₂Si₄O₁₄:Eu²⁺ borosilicate phosphor inspired by natural minerals, which has been synthesized by traditional high temperature solid-state method. The structural information and photoluminescence characteristics of Ba₂CaB₂Si₄O₁₄:Eu²⁺ were characterized in detail, and applied to the fabrication of white LED devices. Excited by near ultraviolet light at 365 nm, it displays a wide emission band from 400 to 800 nm centered on the 595 nm peak. White LED devices were fabricated by physically mixing the yellow phosphor Ba₂CaB₂Si₄O₁₄:Eu²⁺ and synthesized blue phosphor BaMgAl₁₀O₁₇:Eu²⁺ with 365 nm UV chip as excitation. The correlation color temperature (CCT) value and the chromaticity coordinates of the fabricated WLED devices were found to be 5522 K and (0.3293, 0.3036) respectively. In conclusion, Ba₂CaB₂Si₄O₁₄:Eu²⁺ has great potential in the preparation of near UV excited white LEDs.