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

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.