Novel far-red-emitting SrGdAlO 4 :Mn 4+ phosphors with excellent responsiveness to phytochrome P FR for plant growth lighting.

In this work, we reported on novel far-red-emitting SrGdAlO 4 :Mn 4+ (SGA:Mn 4+ ) phosphors towards application in plant growth lighting. The crystal structure and luminescence properties were investigated on the basis of X-ray diffraction, excitation and emission spectra, luminescence decay curves and temperature-dependent photoluminescence spectra. When excited by 353 nm, the SGA:Mn 4+ phosphors showed a far-red emission band in the 650-800 nm wavelength range with peaks at 709 and 725 nm, which was due to the 2 E g → 4 A 2g electron transition of Mn 4+ ion. The optimal Mn 4+ doping concentration was about 0.1 mol%. The CIE chromaticity coordinates of the SGA:0.1%Mn 4+ sample were (0.7064, 0.2934). The luminescence decay lifetimes decreased gradually from 1.263 to 0.868 ms with the increasing Mn 4+ concentrations. Notably, the emission band of SGA:0.1%Mn 4+ sample was well-matched with the absorption spectrum of phytochrome P FR , which indicated the SGA:Mn 4+ were potential far-red-emitting phosphors for plant growth applications.