Regulating chromium ions site occupancy and enhancing near-infrared luminescence properties of Sr2P2O7:Cr3+ phosphor through synthesizing under reduction atmosphere

In recent years, near-infrared phosphor converted light-emitting diodes have gained extensive attention. Broadband near-infrared-emitting phosphors have become a hot research topic as well, which are crucial for advanced near-infrared-emitting light sources based on blue LEDs. In this work, a novel near-infrared phosphor Sr2P2O7:Cr3+ is developed with the emissions (700 − 1200 nm) completely in the near-infrared spectral range. Interestingly, by sintering in a reducing atmosphere, the luminescence of the phosphor is vastly enhanced by 13 − 14 times compared with the sample calcined in the air, which can be attributed to the difference in the lattice sites occupancy, maintaining the valence state of Cr3+and changes in the crystal field environment. The phosphor also exhibited good temperature sensitivity and may be used as a luminescence thermometer. Herein, a practicable and effective strategy is provided to explore and optimize more Cr3+-doped near-infrared phosphors just in a simple way.