Mixed-Valence-Driven Quasi-1D SnIISnIVS3 with Highly Polarization-Sensitive UV-vis-NIR Photoresponse

Mixed-valence states can bring unexpected unique phenomena, especially novel anisotropic physics, due to structural asymmetry, which originate from the discrepant distribution of atoms with different valence. This study reports an unexploited mixed-valence-driven quasi-1D (SnSnS3)-Sn-II-S-IV crystal, which exhibits widely and distinctively anisotropic polarized-light absorption reaching approximate to 3.4 from the deep ultraviolet to near-infrared region (250-850 nm). The fabricated polarization-sensitive photodetectors based on highly air-stable (SnSnS3)-Sn-II-S-IV nanowires display strong linear dichroism among the UV-vis-NIR spectrum with responsivity exceeding approximate to 150 A W-1. Furthermore, the devices are further constructed onto a flexible polyethylene terephthalate (PET) substrate and the photoresponse remains roughly unchanged after repeated bending. This work based on novel mixed-valence-driven quasi-1D ternary sulfide (SnSnS3)-Sn-II-S-IV excites interest in low-symmetry semiconductors for developing broadly spectral polarization-sensitive photodetectors with environmental stability and mechanical flexibility.