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.