Sr2LaSbO6:Mn4+ far-red phosphor for plant cultivation: Synthesis, luminescence properties and emission enhancement by Al3+ ions

A series of novel Mn4+-activated double pemvskite antimonate Sr2LaSbO6 (SLSO) far-red emitting phosphors were successfully synthesized by a high-temperature solid-state method. X-ray diffraction (XRD), photoluminescence excitation (PLE) and emission (PL) spectra, temperature-dependent photoluminescence spectra, CIE chromaticity coordinates, as well as internal quantum efficiency (IQE) were used to analyze these phosphor samples. Under 334 nm excitation, the SLSO:Mn4+ phosphors emit far red emission peaking around 694 nm due to the Mn4+: 2Eg ->(4)A(2g) transition. The optimal doping concentration of Mn4+ was 0.8 mol%, moreover, the critical distance (R-c) was 40.89 angstrom. The dipole-quadrupole interaction may be responsible for the concentration quenching mechanism of Mn4+ ions in the SLSO:Mn4+ phosphors. Furthermore, various Al3+ improved SLSO:0.008Mn(4+) phosphors are investigated. When Al3+ is doped with 0.8%, the PL intensity increased by 2.92 times. In addition, the IQE of SLSO:0.008Mn(4+) and SLSO:0.008Mn(4+), 0.008Al(3+) were found to be as high as 35.2% and 38.1%, respectively. Impressively, all chromaticity coordinates of samples located in far-red region. Therefore, these superior luminescence properties of SLSO:Mn4+ sample demonstrated its potential applications in plant cultivation and growth light-emitting diodes (LEDs).