Synthesis and optical properties of Mn4+ activated double-perovskite niobate deep red phosphors for WLEDs and plant cultivation

Abstract

Mn 4+ doped oxides red phosphors have great potential for white-light-emitting diodes (WLEDs) and plant growth light. Herein, deep red phosphors Ba 2 LuNbO 6 :xMn 4+ with perovskite structure were synthesized by solid state method in air atmosphere. The crystal structure, morphology, composition and optical properties of Ba 2 LuNbO 6 :Mn 4+ phosphors were systematically studied by X-ray diffraction, Rietveld refinement, SEM and EDS and photoluminescence spectra. Under excitation by 380 nm NUV light, the phosphor emitted bright red light around 670 nm and far-red light around 697 nm owing to the spin-forbidden 2 E g → 4 A 2g transition of Mn 4+ ions. Temperature-dependent photoluminescence spectra confirmed the high thermal stability of Mn 4+ -activated Ba 2 LuNbO 6 phosphors. The fluorescence intensity maintained about half of the initial intensity at 400 K, and the thermal quenching was due to the increase of non-radiative transitions at high temperature. Finally, LED devices were fabricated using 365 nm NUV chips with commercial blue, green phosphors and Ba 2 LuNbO 6 :Mn 4+ red phosphors for the use of outdoor lighting, which had color rendering index (CRI) of 84.4 and color temperature (CCT) of 5710 K. The results indicate that Ba 2 LuNbO 6 :Mn 4+ phosphors have great potential as a deep red phosphor in the field of WLEDs and plant growth light. • Deep red phosphor Ba 2 LuNbO 6 :Mn 4+ were prepared by high temperature solid state method in air atmosphere for WLEDs and plant cultivation. • The Ba 2 LuNbO 6 :Mn 4+ phosphor presents deep red emission from 650 nm to 720 nm. • Ba 2 LuNbO 6 :Mn 4+ phosphors have excellent photoelectric performance for LED application.