Bright red luminescence from Mn4+ ions doped Sr2LuTaO6 double-perovskite phosphors

This paper reported on the synthesis, crystal structure and photoluminescence properties of novel deep-red emitting Mn4+ ions doped Sr2LuTaO6 (SLT) double-perovskite phosphors. The SLT:Mn4+ red phosphors were successfully synthesized by high-temperature solid-state route under air atmosphere. The phase purity and crystal structure of these as-prepared SLT:Mn4+ red phosphors were analyzed by X-ray diffraction (XRD) patterns and XRD Rietveld refinement. The luminescence properties including excitation and emission spectra, luminescence decay lifetimes, the Commission International De IʼEclairage (CIE) chromaticity coordinates, temperature-dependent photoluminescence spectra, and internal quantum efficiency were investigated in detail. It was found that under 346 nm excitation, the SLT:Mn4+ phosphors exhibited bright red emissions around 686 nm in the 630–750 nm wavelength range. Besides, Mn4+ concentration dependent luminescence properties were also analyzed, and the optimal doping concentration of Mn4+ ions was found to be 0.4%. More importantly, the CIE chromaticity coordinates of SLT:0.4%Mn4+ sample were determined to be (0.7286, 0.2714), and its internal quantum efficiency was measured as 37%.