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A blue phosphor Ca2PO4Cl:Eu2+(CAP:Eu2+) was synthesized by solid state reaction.The Ca2PO4Cl:Eu2+ exhibited high quantum efficiency and excellent thermal stability.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+.The optimal doping concentration was observed to 11 mol.% of CAP:Eu2+.The energy transfer between Eu2+ 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 Ca2PO4Cl:Eu2+,green-emitting(Ba,Sr)2SiO4:Eu2+ and red-emitting CaAlSiN3:Eu2+ phosphors were selected in conjunction with 400 nm chip to fabricate white LED devices.The average color-rendering index Ra and correlated color temperature(Tc) 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.
A blue phosphor Ca2PO4Cl: Eu2 + (CAP: Eu2 +) was synthesized by solid state reaction.The Ca2PO4Cl: Eu2 + exhibited high quantum efficiency and excellent thermal stability. The luminescent intensity of Ca2PO4Cl: Eu2 + was found to be 128% under excitation at 380 nm, The optimal doping concentration was observed to 11 mol.% Of CAP: Eu2 +. The energy transfer between Eu2 + ions in CAP was created via electric multipolar interaction, and the critical transfer distance was estimated to be 1.26 nm. A mixture of blue-emitting Ca2PO4Cl: Eu2 +, green-emitting (Ba, Sr) 2SiO4: Eu2 + and red- emitting CaAlSiN3: Eu2 + phosphors were selected in conjunction with 400 nm chip to fabricate white LED devices.The average color-rendering index Ra and correlated color temperature (Tc) of the white LEDs were found to be 93.4 and 4590 K, respectively. These results indicate that it was a promising candidate as a blue-emitting phosphor for the near-UV white light- emitting diodes.