Ca2PO4Cl : Eu2+: an intense near-ultraviolet converting blue phosphor for white light-emitting diodes

Abstract

A blue phosphor Ca2PO4Cl : Eu2+ was synthesized by solid state reaction and evaluated as a candidate for white LEDs. The luminescent intensity of Ca2PO4Cl : Eu2+ was found to be 128% under excitation at 380 nm, 149% under 400 nm, and 247% under 420 nm, as high as that of BaMgAl10O17 : Eu2+. Furthermore, Ca2PO4Cl : Eu2+ reveals high quantum efficiency and excellent thermal stability. By utilizing a mixture of blue-emitting Ca2PO4Cl : Eu2+, green-emitting (Ba,Sr)2SiO4 : Eu2+ and red-emitting CaAlSiN3 : Eu2+ as light converters, an intense white GaN-based n-UV-LED (400 nm) was fabricated to exhibit an excellent color-rendering index Ra of 93.4 at a correlated color temperature of 4590 K. Based on the results, we are currently evaluating the potential application of Ca2PO4Cl : Eu2+ as a blue-emitting near-UV convertible phosphor.