Sb2Se3 Microbelt/PEDOT Heterojunction for a Self-Powered Visible to Near-Infrared Photodetector with High Polarization-Sensitive Imaging

Self-powered polarization-sensitive photodetectors play an important role in considerable fields such as navigation, military reconnaissance, and medical imaging. In this paper, a Sb2Se3/PEDOT heterojunction was developed by spraying a PEDOT film to a single Sb2Se3 microbelt (MB) with high crystallinity, synthesized using the CVD process. The self-powered Sb2Se3/PEDOT photodetector (PD) exhibits high polarization-sensitive and broadband detection in the visible–near-infrared range (368–1300 nm). The device achieves a high on/off ratio of 1804, maximum responsivity and specific detectivity of 2.33 A W–1 and 3.84 × 1012 Jones, and fast response time (23 ms/60 ms) at 724 nm under zero bias. The Sb2Se3/PEDOT PD exhibits excellent polarization sensitivity characteristics with the highest anisotropy ratio of 1.7 under 724 nm at zero bias, which is 1.13 times higher compared to the Sb2Se3 PD (1.32) at 0.2 V. The enhanced ability to detect polarized light of the Sb2Se3/PEDOT PD can be attributed to inherent anisotropy of the Sb2Se3 MB and good polarization-sensitivity of PEDOT to form a type II heterojunction, which is suitable for fast separation of photogenerated carriers. Excellent imaging capabilities of the letters “JN” and sensitivity to polarized light at 724 nm have been established for the high-resolution single-pixel image sensor at 0 V bias. This work demonstrates an effective strategy for high-optical response, self-powered, polarization-sensitive photodetection, and imaging using Sb2Se3/PEDOT heterojunctions.