Cation-tunable blue phosphor Ca2PO4Cl:Eu2+: enhancive emission and site occupancy

A series of blue phosphors Ca1.98-xMxPO4Cl:0.02Eu(2+) (M=Mg and Sr) with different values of x were synthesized using a high-temperature solid-state reaction. X-Ray diffraction and photoluminescence measurements were used to study the phase structure and luminescence properties. Ca2PO4Cl:0.02Eu(2+) exhibits a tunable emission intensity and color due to the incorporation of Sr2+ or Mg2+. The incorporation of Sr2+ reduces the luminescence intensity and results in a slight red shift in the emission band. The incorporation of Mg2+ results in enhanced emission and a clear blue shift in the emission band along with a tunable chromatic coordination. Under excitation at =334nm, the emission intensity of the Mg2+-doped Ca2PO4Cl:0.02Eu(2+) is found to be 250% that of Ca2PO4Cl:0.02Eu(2+). The luminescence behaviors of the as-synthesized phosphors are discussed according to the host crystal structure and site occupancy of Eu2+. The results indicate that Mg2+-doped Ca2PO4Cl:Eu2+ is more applicable as a near-UV-convertible blue phosphor for white light-emitting diodes. Copyright (c) 2015 John Wiley & Sons, Ltd.