Investigation of enhanced far-red emitting phosphor GdAlO3:Mn4+ by impurity doping for indoor plant growth LEDs

Abstract Phytochrome is indispensable for plant growth, which can absorb light useful for sprout, blossom, fruits. Generally, Phytochrome PR absorbs red light and Phytochrome PFR absorbs far-red light. The emission of Mn4+ doped GdAlO3 is situated in far-red light region. Herein, GdAlO3:Mn4+, Mg2+(GAL:Mn4+, Mg2+) phosphors were successfully synthesized via sol-gel method and the crystalline structure and luminescence properties were investigated systematically. Impressively, the emission intensity of GAL: Mn4+ phosphors was raised by Mg2+ and Ge4+ doping, and the mechanism of improved luminescence was also discussed. Depending on photoluminescence excitation and photoluminescence spectroscopy, the crystal field strength of the GdAlO3 host was calculated. In addition, excellent color purity and good thermal stability were found in Mg2+ co-doped GdAlO3:Mn4+ phosphors. Furthermore, the luminescence spectrum of GAL: Mn4+, Mg2+ phosphor was agreed well with the absorption of Phytochrome PFR, which convincingly confirmed that Mg2+ co-doped GdAlO3:Mn4+ phosphors show promise in indoor plant growth LEDs.