Enhanced luminescence performances of Mn4+-activated Sr4Al14O25 red phosphors by doping with Sc3+ ions

Abstract

A series of non-rare earth Mn4+-activated strontium aluminate phosphors Sr4Al14O25:Mn4+ co-doped with Sc3+ ions were successfully synthesized by a high-temperature solid-state reaction method. XRD result reveals that there is no introduction of additional phase but expansion of lattice with incorporation of Sc3+ ions. Excitation and emission spectrum measurement shows that the synthesized phosphors can be efficiently excited by near-ultraviolet and blue light, and a deep red emission centered at 652 nm with a narrow full width at half maximum (FWHM) can be obtained, which is attributed to the transition 2E→4A2 of Mn4+ ions. In addition, the crystal field strength parameter (Dq) and Racah parameters (B, C) and energies of states were calculated based on experimental data. Moreover, the luminous intensity of Sr4Al14-xScxO25:Mn4+ is enhanced and increased by 60% compared with Mn4+ single incorporated sample at x = 0.06. A phenomenon of redshift is observed in the excitation spectrum and discussed systematically. Finally, the mechanism of the positive effects with Sc3+ ions incorporated into lattice is discussed in detail. All the results suggest that the Sr4Al13.94Sc0.06O25:Mn4+ phosphor will become one of the great candidates for backlight of LCD.