A broadband yellow-green emitting mixed orthoborate–pyroborate phosphor, Ba2Sc2B4O11:Ce3+, for white light emitting diodes

Abstract

The development of yellow-green phosphors for high quality white light emitting diodes (WLEDs) is critical. Herein, we successfully synthesized a mixed orthoborate–pyroborate phosphor, Ba₂Sc₂B₄O₁₁:Ce³⁺, using a high-temperature solid-state method, which exhibits bright yellow-green emission with a peak located at 540 nm and a full width at half maximum (FWHM) of 130 nm under 410 nm light excitation. In addition, the crystal structure, morphology, and thermal quenching properties of Ba₂Sc₂B₄O₁₁:Ce³⁺ were investigated in detail. The quantum yield of the optimal sample was found to be 53.3%. The concentration quenching occurred through the energy transition between the nearest-neighbor Ce³⁺ ions. A WLED with a low correlated color temperature (CCT = 3906 K) and a high color rendering index (R_a = 89) was prepared by coating the mixture of the phosphor Ba₂Sc₂B₄O₁₁:Ce³⁺, the commercial blue phosphor BaMgAl₁₀O₁₇:Eu²⁺ and the red phosphor CaAlSiN₃:Eu²⁺ on a 395 nm n-UV LED chip. The results show that the yellow-green phosphor Ba₂Sc₂B₄O₁₁:Ce³⁺ could be an excellent candidate for WLEDs.