Octahedron vacancy induced luminescence improvement of double perovskite type phosphors LaMg2/3-xNb1/3O3:Mn4+ with multifunctional applications

Near infrared (NIR) phosphors have been booming as promising candidates for agriculture due to the adjustable spectrum and excellent match with the dyes of the plants. Here, Mn4+ activated double perovskite LaMg2/3Mn1/3O3 NIR phosphor was prepared, which showed high match with the absorption spectra of phytochrome PFR. Concentration of Mg2+ was decreased to create octahedron vacancy into the lattice to improve the luminescence performance. Structure and luminescence variation of the phosphors LaMg2/3-xNb1/3O3:Mn4+ along with the increased vacancy concentration were carried out. Relative sensitivity Sr of the optimized LaMg0.57Nb0.33O3:Mn4+ reaches 3.109 % and exhibits great application potential in temperature sensor. Both the NIR light emitting diode (LED) and white LED were fabricated by using this double perovskite NIR phosphor and applied to the cultivation of dragon fruit as light compensation. The dragon fruits matured faster than those without any light compensation. These results confirm the great application potential of this double perovskite NIR phosphor in temperature sensor and plant cultivation.