Luminescence and Crystallographic Sites of Eu~(2+) in KNaCa_2(PO_4)_2

A blue phosphor,KNaCa2(PO4)2:Eu2+,was prepared by the high temperature solid-state method,and its luminescent characteristics were investigated.The spectral characteristics show that it can be effectively excited by near ultraviolet light(400 nm),and exhibits blue light(470 nm).The crystallographic sites of Eu2+ in KNaCa2(PO4)2 are calculated by van Uitert formula.In KNaCa2(PO4)2:Eu2+,the emission band centered at 461 nm originates from the Eu2+ center of the eight compounds,and the emission band centered at 502 nm originates from the Eu2+ center of the six compounds.The influence of Eu2+ concentration on the emission intensity of the phosphor is investigated.The re-sult shows that the emission intensities firstly increase with the increase in Eu2+ concentration,reach a maximum at 1mol% Eu2+,and then decrease.The concentration quenching mechanisms are the d-d interaction by Dexter theory.