Highly distorted Cr3+-doped fluoroantimonate with high absorption efficiency for multifunctional near-infrared spectroscopy applications

The growing near-infrared (NIR) spectroscopic technology has significantly prompted extensive exploration of broadband NIR-emitting phosphors. Cr3+-doped fluorides have recently emerged as a new prototype NIR emitter, whereas they endure low external quantum efficiency (EQE) limited by low absorption efficiency (AE < 30%). Here, an extremely high AE ∼56.2% is firstly realized in a highly distorted fluoroantimonate NaSbF4 and newly developed in multifunctional NIR spectroscopy applications. Formation energy and distortion index calculation demonstrate that Cr3+ occupies an inherently highly distorted [SbF6E] octahedron in a low local symmetry monoclinic structure and achieves a large parity-forbidden transition (4T2→4A2) probability of Cr3+. Moreover, NaSbF4:Cr3+ exhibits excellent stability against UV radiation, thermal impact, and extended device operation. The NIR phosphor-converted lighting-emitting diode (pc-LED) produces a photoelectric conversion efficiency of 10.48% at 20 mA and realizes non-destructive precision inspections of circuit boards, veins imaging, and night vision. Further combination with white pc-LED produces a full-VIS-NIR spectrum device applied to plant growth lighting. These findings open a new matrix model with aberrant crystal structures for high AE and advance the multifunctional NIR pc-LED applications covering industrial detection, bio-imaging, and modern agriculture.