Deep-red-emitting Mg2InSbO6:Mn4+ phosphors with a double-perovskite structure for plant-cultivation LEDs: Synthesis and photoluminescence properties

In this study, novel deep-red-emitting Mg2InSbO6:Mn4+ phosphors were prepared through a high-temperature solid-state reaction. The as-prepared phosphors belong to the perovskite structure with the space group of R3‾ (No.148). The calculated energy gap value of Mg2InSbO6 is ~1.788 eV. Emission spectrum of the Mg2InSbO6:0.3%Mn4+ was obtained under 301 nm excitation, which centered 665 nm due to the 2Eg→4A2g transition. The optimum concentration of Mg2InSbO6:xMn4+ is confirmed to 0.3% mol, and the concentration quenching effect is ascribed to the dipole–dipole interaction. The relative temperature-dependent PL spectra demonstrate that phosphors possess commendable repeatability and high activation energy. The chromaticity shift diagram shows the phosphors have good resistance of color drifting. The Mg2InSbO6:0.3%Mn4+ phosphor has a high color purity of 99.8%. Furthermore, a red light-emitting diode is fabricated with Mg2InSbO6:0.3%Mn4+ phosphor and a 365 nm near-ultraviolet chip. The emission spectrum of the red LED is perfectly overlapped with plant pigments (chlorophyll a and chlorophyll b) absorption spectrum. Thus, Mn4+-activated Mg2InSbO6:Mn4+ phosphors have the potential to apply in plant-cultivation LEDs.