Investigation on luminescence of red-emitting Mg3Ca3(PO4)(4):Ce3+,Mn2+ phosphors

To realize red emission, the Ce3+-Mn2+ activated Mg3Ca3(PO4)(4) phosphors were synthesized by solid-state reaction. The phase and luminescence properties of the as-prepared samples were characterized by using XRD and photoluminescence spectra. XRD result showed that single-phase samples were obtained successfully. The diffuse reflection spectrum of Mg3Ca3(PO4)(4) revealed that two main absorptions existed, and the optical band gap was calculated to be about 5.31 eV. For Ce3+ doped Mg3Ca3(PO4)(4), a broad emission band from 300 to 500 nm was observed under 254 nm excitation, which was due to the d-f transition of Ce3+; by monitoring 352 nm, the excitation spectrum covered the region from 240 to 340 nm. The Ce3+-Mn2+ co-doped Mg3Ca3(PO4)(4) showed an efficient energy transfer from Ce3+ to Mn2+ upon 254 nm excitation, and the red emission was obtained by adjusting the relative concentrations of Ce3+ and Mn2+.