Luminescent properties of broad band far red emitting Zn 3 Ga 2 GeO 8 : Mn 2+ , Ca 2+ phosphors for indoor plant growth LED

series of Mn 2+ -doped solid Zn 3 Ga 2 GeO 8 materials with far-red broad-band emissions is prepared as promising candidates for light emitting diodes (LEDs) for application in indoor plant cultivation. Phosphor exhibits broad far-red emissions, ranging from 600 to 1100 nm which overlap with the absorption range of the phytochrome ( P_fr ). In addition, the co-doping with Ca 2+ contributes a 1.57-fold increase in the far-red-emission intensity at room temperature. Encapsulating phosphor onto ultraviolet LED chips yields far-red-emitting LED devices, which can be promising candidates for promoting indoor plant cultivation.