Surface engineering of highly ordered Bi₂S₃ film with open channels toward high-performance broadband photodetection

The highly ordered film assembled by regularly 1D nanostructures has potential prospects in electronic, photoelectronic and other fields because of its excellent light-trapping effect and electronic transport property. However, the controlled growth of highly ordered film remains a great challenge. Herein, large-area and highly ordered Bi₂S₃ film is synthesized on fluorophlogopite mica substrate by chemical vapor deposition method. The Bi₂S₃ film features hollowed-out crosslinked network structure, assembled by 1D nanobelts that regularly distribute in three orientations, which agrees well with the first principles calculations. Based on the as-grown Bi₂S₃ film, the broadband photodetector with a response range from 365 to 940 nm is fabricated, exhibiting a maximum responsivity up to 98.51 mA W^–1, specific detectivity of 2.03 × 10¹⁰ Jones and fast response time of 35.19 ms. The stable instantaneous on/off behavior for 500 cycles and reliable photoresponse characteristics of the Bi₂S₃ photodetector after storage in air for 6 months confirm its excellent long-term stability and air stability. Significantly, as sensing pixel and signal receiving terminal, the device successfully achieves high-resolution imaging of characters of “H”, “I” and “T”, and secure transmission of confidential information. This work shows a great potential of the large-area and highly ordered Bi₂S₃ film toward the development of future multiple functional photoelectronic applications. (Figure presented.).