Synthesis, structure and optical properties of cerium-doped calcium barium phosphate – a novel blue-green phosphor for solid-state lighting

Abstract

A new blue-green phosphor, Ca₆BaP₄O₁₇:Ce³⁺, which can be prepared by conventional solid-state synthesis, is reported as a candidate phosphor for solid-state lighting with near-ultraviolet LEDs. Under excitation at around 400 nm, Ca₆BaP₄O₁₇:Ce³⁺ shows strong blue-green emission with the peak position at 477 nm. Ce³⁺,Si⁴⁺ co-doping is found to enhance the luminous intensity, and the unique emission characteristics of this combination are studied and related to the crystal structure. Ca₆BaP₄O₁₇ is an exceptional host material, which also accommodates Eu²⁺, emitting strong yellow light under 400 nm excitation. A fabricated white LED, combining Ca₆BaP₄O₁₇:Ce³⁺,Si⁴⁺ with Ca₆BaP₄O₁₇:Eu²⁺ and a red CaAlSiN₃:Eu²⁺ phosphor, achieved a luminous efficacy of 45 lm W⁻¹ with a color-rendering index of 93 around the correlated color temperature of 4500 K.