Sensitive solution-processed Bi₂S₃ nanocrystalline photodetectors

Solution-processed nanocrystal optoelectronic devices offer large-area coverage, low cost, and compatibility with a wide range of substrates. Recently, photodetectors and photovoltaics based on spin-coated nanoparticle films have shown tremendous progress in performance. However, high-performance devices reported to date have employed either Pb or Cd, raising concerns regarding environmental impact and regulatory acceptance. Herein we report a high-performance solution-processed photodetector based instead on Bi ₂S₃ nanocrystals. The devices exhibit photoconductive gain on the order of 10 combined with temporal response on the 10 ms time scale. The resultant solution-processed Bi₂S₃ nanorod photoconductive photodetectors are of interest in visible and near-infrared (NIR) wavelength applications requiring video-frame-rate temporal response.