Environmentally-friendly and low-cost Fe3+-doped broadband NIR light-emitting phosphors

Near infrared (NIR) light emitting phosphors have attracted more and more attention with the development of science and technology. Herein, we report a series of environmentally-friendly low-cost Fe3+-activated ZnGa2O4 phosphors which exhibit intense broadband NIR light emitting. According to density functional theory (DFT) calculations, ZnGa2O4 host possesses an indirect wide bandgap. The emission of the Fe3+-doped phosphors demonstrates a wide band spanning from 650 to 850 nm, with the maximum at 720 nm and a full width at half maxima (FWHM) of 70 nm, showing a large overlap with the absorption of phytochromes (PR and PFR). The luminescence intensity remains at 71% when the temperature is raised to 423 K. The phosphors are fabricated into light emitting diodes (LEDs) which produces strong NIR emission with CIE color coordinates of (0.65, 0.31). All these results suggest that ZnGa2O4:Fe3+ is a promising NIR luminescent material, which is expected to be a candidate for indoor plant culture LEDs.