Synthesis and optical properties of KCaPO4:Eu2+ phosphor

A series of Eu2+ doped KCaPO4 phosphors were prepared by high temperature solid state reaction and an efficient blue–green emission was observed. The photoluminescence (PL) spectrum of the phosphor appeared one asymmetric peak under near-ultraviolet (n-UV) excitation and two emission bands at 480 nm and 540 nm were obtained using Gaussian fit, which was because Eu2+ ions inhabited two different Ca2+ sites: Eu(I) and Eu(II) in the host lattice, respectively. The excitation spectrum was a broadband extending from 250 to 450 nm, which matched well with the emission of ultraviolet light-emitting diodes (UV LEDs). The effect of Eu2+ concentration on the emission intensity of KCaPO4:Eu2+ phosphor was investigated in detail.