Improved luminescence and afterglow emission from Mn2+/Si4+ co-doped AlN by combustion synthesis method

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• A Mn 2+ /Si 4+ co-doped strategy was used to improve both luminescence and afterglow properties of the orange-red AlN phosphor by combustion synthesis. • The mechanisms behind this promotion were discussed in detail. • A more reasonable identification of the excitation spectral term of AlN:Mn 2+ is proposed. • The effect of Si 4+ on the morphology of as-synthesized AlN:Mn 2+ phosphors was observed. An orange-red emitting Mn 2+ /Si 4+ co-doped AlN phosphor was prepared by an efficient combustion synthesis method. Phase identification and structure characterization were performed using powder X-ray diffraction (XRD) and refined by the Rietveld method. Luminescence and afterglow properties of the AlN-based phosphors such as photoluminescence spectra (PL), CIE values, afterglow decay curves, thermoluminescence glow curves (TL) were systematically studied. Using the Tanabe-Sugano diagram, the Racah parameters B , C , and crystal field splitting parameter Dq of as-prepared phosphor were calculated to be 812 cm −1 , 2168 cm −1 , and 780 cm −1 , respectively. The luminescence intensity and afterglow time were increased, respectively, by about 1.1 and 2.2 times after 3% Si 4+ co-doping. Particular attention was paid to study the mechanism of Si 4+ co-doping on improving luminescence properties using a combination of the above-mentioned method and X-ray photoelectron spectroscope (XPS). Two hypothetical stress cancellation and charge rebalance effects due to Si 4+ co-doping were discussed. Besides, it was found a shallower trap level (0.56 eV, compared to 0.84 eV for those without Si 4+ co-doping) was formed after the co-doping of Si 4+ , which results in enhanced afterglow performance.