Broadband emitting Fe³⁺-doped double perovskite-type antimonates phosphors for NIR spectroscopy applications

Near-infrared (NIR) broadband emitting phosphors regarded as ideal miniaturized NIR light sources, have recently received considerable attention. Nevertheless, the lack of appropriate substitutes for poisonous Cr3+ still poses a significant obstacle. Here, by selecting double perovskite-type antimonates compound Ca2LuSbO6 (CLSO) and Ca2YSbO6 (CYSO) as the hosts, the broadband NIR-emitting CLSO: 0.008Fe(3+) and CYSO: 0.01Fe(3+) phosphors are firstly reported. The above materials exhibit a rare long-wavelength NIR emission band peaking at 927 and 938 nm, respectively. Accordingly, their full widths at half maximum are 128 and 135 nm, respectively. Moreover, the mechanism of their concentration quenching and thermal quenching effect are discussed. The IQEs of CLSO: 0.008Fe(3+) is measured to be 69%, which is superior to many available Fe-activated phosphors. Integrating the bond valence theory analysis with electron paramagnetic resonance measurement, Fe3+ only substitutes the lattice site of the Sb atom to generate a [FeO6] octahedron accompanying lattice distortion. Significantly, the as-fabricated phosphor-converted light emitting diodes device shows substantial applications in night vision and NIR spectroscopy detection. This work contributes to novel insights into the photoluminescence and site occupancy of Fe3+, thereby paving a new avenue for exploring next-generation environmentally-friendly and nontoxic NIR light-emitting materials.