Ca(2)PO(4)Cl : Eu(2+): an intense near-ultraviolet converting blue phosphor for white light-emitting diodes

Abstract

A blue phosphor Ca(2)PO(4)Cl : Eu(2+) was synthesized by solid state reaction and evaluated as a candidate for white LEDs. The luminescent intensity of Ca(2)PO(4)Cl : Eu(2+) was found to be 128% under excitation at 380 nm, 149% under 400 nm, and 247% under 420 nm, as high as that of BaMgAl(10)O(17) : Eu(2+). Furthermore, Ca(2)PO(4)Cl : Eu(2+) reveals high quantum efficiency and excellent thermal stability. By utilizing a mixture of blue-emitting Ca(2)PO(4)Cl : Eu(2+), green-emitting (Ba, Sr)(2)SiO(4) : Eu(2+) and redemitting CaAlSiN(3) : Eu(2+) as light converters, an intense white GaN-based n-UV-LED (400 nm) was fabricated to exhibit an excellent color-rendering index R(a) of 93.4 at a correlated color temperature of 4590 K. Based on the results, we are currently evaluating the potential application of Ca(2)PO(4)Cl : Eu(2+) as a blue-emitting near-UV convertible phosphor.