title: Cation-tunable blue phosphor Ca₂PO₄Cl:Eu²⁺: enhancive emission and site occupancy.
abstract: A series of blue phosphors Ca(1.98-x)M(x)PO4Cl: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 Sr(2+) or Mg(2+). The incorporation of Sr(2+) reduces the luminescence intensity and results in a slight red shift in the emission band. The incorporation of Mg(2+) results in enhanced emission and a clear blue shift in the emission band along with a tunable chromatic coordination. Under excitation at λ = 334 nm, the emission intensity of the Mg(2+)-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 Eu(2+). The results indicate that Mg(2+)-doped Ca2PO4Cl:Eu(2+) is more applicable as a near-UV-convertible blue phosphor for white light-emitting diodes.
authors.affiliation: Key Laboratory of Rare Earth Optoelectronic Materials and Devices, Department of Chemistry and Chemical Engineering, Huaihua University, Huaihua, People's Republic of China.
authors.forename: Wanping
authors.initials: W
authors.lastname: Chen
authors.affiliation: Key Laboratory of Rare Earth Optoelectronic Materials and Devices, Department of Chemistry and Chemical Engineering, Huaihua University, Huaihua, People's Republic of China.
authors.forename: Ahong
authors.initials: A
authors.lastname: Zhou
mesh_terms: D002118:Calcium / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D002713:Chlorine / Q000737:chemistry*; D005063:Europium / Q000737:chemistry*; D049449:Luminescence; D049408:Luminescent Agents / Q000138:chemical synthesis / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*
chemical_list: D002412:Cations; D049408:Luminescent Agents; D010710:Phosphates; D005063:Europium; D002713:Chlorine; D002118:Calcium
keywords: LED; luminescence; phosphors