Phosphors Ba2LaTaO6:Mn4+ and its alkali metal charge compensation for plant growth illumination

A series of Mn4+-doped and Mn4+,K+-co-doped Ba2LaTaO6 (BLT) double-perovskite phosphors was synthesized using a high-temperature solid-state reaction. The phase purity and luminescence properties were also studied. The optimum doping concentration of Mn4+ and K+ was obtained by investigating the photoluminescence excitation spectra and photoluminescence emission spectra. The comparison of BLT:Mn4+ phosphors with and without K+ ions shows that the photoluminescence intensity of K+-doped phosphors was greatly enhanced. This is because there was a charge difference when Mn4+ ions were doped with Ta5+ ions in BLT. Mn4+-K+ ion pairs were formed after doping K+ ions, which hinders the nonradiative energy transfer between Mn4+ ions. Therefore, the luminescence intensity, quantum yield, and thermal stability of phosphors were enhanced. The electroluminescence spectra of BLT:Mn4+ and BLT:Mn4+,K+ were measured. The spectra showed that the light emitted from the phosphors corresponded well with chlorophyll a and phytochrome P-R. The results show that the BLT:Mn4+,K+ phosphors had good luminescence properties and application prospects and are ideal materials for plant-illuminated red phosphors.