Ultrafast and Sensitive Photon Counters Based on Solution-Processed Chalcogenide Thin Films for Multiple Applications

Due to their excellent optoelectronic properties and material stability, chalcogenide semiconductors have been successfully introduced for photovoltaics, photodetectors, and photocatalysis. However, current chalcogenide-based photodetectors are still struggling to achieve both low noise and high sensitivity simultaneously, mainly limited by the poor film quality, which is not ideal for practical applications, particularly for weak light detection and photon counting. Here we fabricated high quality Sb₂S₃ and antimony bismuth sulfide thin films via solution-process and achieved photodiodes with excellent performance. Compared to Sb₂S₃, the optimized antimony bismuth sulfide detectors exhibit excellent photon counting capability, including high bias voltage tolerance, low noise and dark count rate at −10 V, high sensitivity, fast response (∼180 ns), and superior stability. More importantly, these devices demonstrated great potential for multiple applications, such as photoluminescence lifetime spectroscopy, optical communication, wastewater monitoring, and heart rate detection.