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

Abstract

A blue phosphor Ca(2)PO(4)Cl:Eu(2+) (CAP:Eu(2+)) was synthesized by solid state reaction. The Ca(2)PO(4)Cl:Eu(2+) exhibited high quantum efficiency and excellent thermal stability. 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+). The optimal doping concentration was observed to 11 mol.% of CAP:Eu(2+). The energy transfer between Eu(2+) ions in CAP were occurred via electric multipolar interaction, and the critical transfer distance was estimated to be 1.26 nm. A mixture of blue-emitting Ca(2)PO(4)Cl:Eu(2+), green-emitting (Ba,Sr)(2)SiO(4):Eu(2+) and red-emitting CaAlSiN(3):Eu(2+) phosphors were selected in conjunction with 400 nm chip to fabricate white LED devices. The average color-rendering index R(a) and correlated color temperature (T(c)) of the white LEDs were found to be 93.4 and 4590 K, respectively. The results indicated that it was a promising candidate as a blue-emitting phosphor for the near-UV white light-emitting diodes.