High quantum efficiency and luminescence properties of far-red Sr3NaTaO6: Mn4+, Ba2+ phosphor for application in plant growth lighting LEDs

Far-red emitting Sr 3 NaTaO 6 : Mn 4+ and Sr 3 NaTaO 6 : Mn 4+ , Ba 2+ phosphors were successfully synthesized by high-temperature solid-state method for the first time. The crystal structure and luminescence properties of phosphors were studied by X-ray diffraction (XRD), photoluminescence (PL), thermal stability, UV–vis spectroscopy and CIE color coordinate in detail. The Sr 3 NaTaO 6 : Mn 4+ phosphor exhibits an intense emission peak at 692 nm under the excitation of 365 nm, which matches well with the absorption spectra of plant pigments of chlorophyll a and b , phytochrome P R and P FR . Besides, by co-doping of Ba 2+ ions, the emission intensity of Sr 3 NaTaO 6 : Mn 4+ phosphors were enhanced 1.1–1.5 times and an internal quantum efficiency (IQE) of 75.1% was obtained. Finally, a LED device was fabricated with the Sr 3 NaTaO 6 : 0.3%Mn 4+ , 0.45%Ba 2+ phosphor and showed an effective promotion on the average stem length, fresh weight, dry weight and chlorophyll content of wheat. The result shows that Sr 3 NaTaO 6 : 0.3%Mn 4+ , 0.45%Ba 2+ phosphor may have a potential application in the fields of plant growth lighting LEDs.