Luminescence and crystallographic sites of Eu~(2+) in KCaPO_4

A blue-greenish phosphor,KCaPO4:Eu2+,was prepared by the high temperature solid-state method,and its luminescent characteristics were investigated.The emission and excitation spectra indicate that it can be effectively excited by ultraviolet and near ultraviolet(300-450 nm) light,and exhibits satisfactory bluegreenish performance(487 nm).The crystallographic sites of Eu2+ in KCaPO4 were calculated by the van Uitert formula.The results show that the 478 nm emission band originates from the eight sites of Eu2+,and the 527 nm emission band comes from the six sites of Eu2+.The effect of Eu2+ content on the emission intensity of this phosphor was investigated.The results show that the intensity firstly increases with increasing Eu2+ content,then decreases,and reaches the maximum at 3% Eu2+.The concentration quenching mechanisms are from the d-d interaction by Dexter theory.