Preparation and luminescence properties of Li2MgZrO4:Mn4+ red phosphor for plant growth

Novel double perovskite Li2MgZrO4:Mn4+(LMZ:Mn4+) phosphor is prepared by high-temperature solid-state reaction method in air. Excitation bands peaking at 335, 395, and 482 nm of LMZ:Mn4+ phosphor in the range of 220-600 nm are attributed to the O2--Mn4+ charge transfer and the (4)A(2)-> T-4(1), T-2(2), and T-4(2) transitions of Mn4+ ion, respectively. Emission band peaking at 670 nm of LMZ:Mn4+ phosphor within the range 610-790 nm is assigned to the E-2 ->(4)A(2) transition of Mn4+ ion with host lattice vibration, which indicate that LMZ:Mn4+ phosphor has an application prospect in the red light-emitting diodes for plant growth. The optimal Mn4+ ion concentration in LMZ:Mn4+ phosphor is similar to 0.4 mol%. Fluorescence lifetime and quantum efficiency of LMZ:0.4%Mn4+ phosphor are similar to 251.47 mu s and 32.3% at room temperature, respectively. The influence of temperature to luminescence properties is explained by the schematic configuration coordinate diagram. The luminous mechanism is explained by the energy level diagram of Mn4+.