Near-infrared emission in perovskite oxides MZrO 3 :Bi (M = Ba, Sr) by dopants’ selective site occupancy

Near-infrared (NIR) emitting materials are essential for spectroscopic analysis, biological imaging and special lighting sources. Herein, broadband NIR emission is achieved in the Bi 3+ activated perovskite oxides MZrO 3 (M = Ba,Sr), and the luminescence mechanism was revealed using the combination of the experimental and first-principles studies. The valence state of the Bi 3+ ions was confirmed to be trivalent in the X-ray photoelectron spectroscopy spectra and the formation energy calculations. The possibility of NIR emission from lower state bismuth is excluded as the reduction atmosphere treatment, and therefore the selective occupancy of Bi 3+ in the Zr 4+ and M 2+ sites enables the luminescence discrepancy in different atmospheres, where the Bi 3+ on M 2+ sites accounts for visible emission while Bi 3+ on Zr 4+ sites shows NIR emission. For the visible emission of Bi 3+, the existence of Ba 2+ vacancy shows remarkable influence on the emission spectra. This work not only provides a novel method to develop Bi-activated NIR emitting materials, but also helps to understand the intrinsic NIR luminescence mechanism of Bi 3+ ions in inorganic compounds.