Enhancement of the self-luminescent intensity of LaSrGaO4 by Cr3+ doping for the absorption of far infrared plant PFR phytochrome

Two series of phosphors of LaSr1-xGaO4:xCr3+ and La1-xSrGaO4:xCr3+were synthesized by a high-temperature solid-state method under the same experimental conditions. The phase structure, surface topography, luminescence properties and luminescence mechanism of phosphors were investigated. LaSrGaO4 host exhibits a narrow emission band peaks at 716 nm which comes from the intrinsic defects. LaSr1-xGaO4:xCr3+ and La1-xSrGaO4:xCr3+ phosphors show emission spectra with the same shape to the host, while the luminous intensity improved greatly. From the analysis of low temperature spectra and decay lifetimes of the samples, it can be concluded that Cr3+ show no intrinsic luminescence in the LaSrGaO4 host. The analysis of TL spectra proved that the defect concentration was increased by Cr3+ doping, and enhanced the intrinsic luminescence. The emission spectrum of the LED device based on the LaSr0.999GaO4:0.001Cr3+ phosphor almost coincides with the absorption spectrum of the PFR phytochrome, which indicated the pc-LED have potential application in the field of plant lighting, especially for the study of the independent regulatory mechanism of PFR.