SbI ₃ -Derived Antimony Chalcoiodides: Phase-Selective Access, Spectroscopic Fingerprints, and Anisotropic Photoresponse

Low-dimensional antimony chalcoiodides with quasi-one-dimensional structures are promising for anisotropic optoelectronics, but phase-selective synthesis and structure–function correlation remain challenging. Herein, we report an SbI3-derived chemical vapor transport platform for the unified synthesis of SbI3, SbSI, SbSeI, and SbTeI. Volatile SbI3 serves as a reactive Sb–I template, enabling branch-specific crystallization upon chalcogen incorporation. Comparative structural and vibrational fingerprints are established to distinguish these related phases. Using single-crystalline SbSI nanowires, we show that tensor-governed Raman anisotropy translates into polarization-sensitive photodetection, with a responsivity of 66.7 mA W–1, a detectivity of 1.09 × 109 Jones, and a photocurrent polarization ratio of 1.7 under 638 nm illumination. This work provides a framework for understanding precursor-directed branch selection and anisotropic functionality in antimony chalcoiodides.