Strongly Anisotropic Quasi‐1D BaTiS₃ Chalcogenide Perovskite for Near‐Infrared Polarized Photodetection

Abstract One‐dimensional (1D) crystal‐structural materials have attracted extensive attention for polarization detection because of the strong anisotropy. Barium titanium sulfide (BaTiS₃), a quasi‐1D chalcogenide perovskite, demonstrates a great potential for polarization detection stemming from the giant optical anisotropy. Whereas, the photoelectric properties of BaTiS₃ and its direct application in polarized photodetector are less studied. Herein, quasi‐1D BaTiS₃ is introduced in polarized photodetection for the first time. The needle‐like BaTiS₃ single crystals are successfully prepared by a modified chemical vapor transport process. The BaTiS₃ single crystal demonstrates a narrow bandgap of 0.8 eV, an n‐type intrinsic conductivity, and a more than 300 cm² V⁻¹ s⁻¹ mobility along the c‐axis. Then, an Ag/BaTiS₃/Ag photoconductive detector is fabricated. It shows a broad detection wavelength ranging from visual light to 1550 nm and high responsivity of ≈1.22 A W⁻¹. Moreover, an orthogonal reverse property of polarization photocurrent is observed under the excitation energy of 1.70 eV and 1.96 eV. These comprehensive characteristics can promote the application of the quasi‐1D BaTiS₃ in near‐infrared polarized photodetection.