Structural and spectroscopic features of high color purity red-emitting phosphors Sr19Mg2(PO4)14: Re3+ (Re3+= Eu3+, Sm3+, Pr3+)

Abstract The discovery of high color purity red-emitting phosphors is a major challenge for solid-state lighting materials. Benefitting from highly condensed and flexible framework structure of β-Ca3(PO4)2-type compounds, we have successfully prepared three different kinds of novel high color purity red-emitting phosphors Sr19Mg2(PO4)14: Re3+ (Re3+= Eu3+, Sm3+, Pr3+) by using traditional sintering method. Rietveld refinement, SEM measurement, absorption spectra, emission/excitation spectra, fluorescence decay analysis and emission spectra in terms of different temperature were investigated and discussed clearly. The matrix optical band gap was calculated to be 4.5 eV by reflection data, which indicated the suitable host for rare earth doping. The single doped Eu3+, Sm3+ and Pr3+ phosphors could respectively exhibit characteristic and strong red emission peaks at 614 nm, 598 nm and 642 nm when excited by (near) ultraviolet radiation. Excitingly, all samples could obtain high color purity with the value of 91.6%, 90.6% and 84.8% for Eu3+, Sm3+, Pr3+ ions, respectively. Moreover, the thermal stability can stay strong which still keep over 75% at 150℃ when comparing with that at atmospheric temperature. The quantum efficiency (QE) is another important parameter for phosphors which were measured to be 46.6% for Eu3+, 53.1% for Sm3+ and 10.3% for Pr3+. The present work indicates that the Sr19Mg2(PO4)14: Re3+ phosphors are efficient red components with extraordinary color purity and high quantum efficiency for industrial applications as solid-state lighting materials.