Solution‐Processed Semiconductive AgBiS 2 Quantum Dot Inks for Environmentally Friendly Near‐Infrared Photodetectors

ABSTRACT Near‐infrared (NIR, 750−1500 nm) photodetectors based on solution‐processed colloidal quantum dots (CQDs) have attracted great interest for emerging optoelectronic applications, including machine vision, autonomous driving, night vision, and biological imaging, etc . However, the currently developed CQDs materials with photoresponse in infrared region usually contain toxic heavy metal elements such as lead and mercury. Herein, for the first time, we employ directly synthesized, eco‐friendly semiconductive AgBiS 2 CQD‐inks as photoactive layers and successfully demonstrate their application in high‐performance NIR photodetectors. The optimized bilayer QD‐based photodetector covers a photoresponse spectral range from 300 nm to 1200 nm, delivering an EQE up to 72%, a responsivity of 0.44 A/W, and a specific detectivity of 5.61 × 10 11 Jones at 760 nm. More importantly, the NIR photodetector exhibits an ultra‐high light‐to‐dark current ( I light / I dark ) ratio of ∼3.5 × 10 4 , a high specific detectivity of ∼1.2 × 10 11 Jones, fast response speed of 6.8 µs/5.7 µs, respectively, under 1064 nm laser illumination at a bias of 0 V. This work reveals that this infrared photodetector based on direct synthesis of environmentally friendly semiconductive CQDs paves the effective path for the future development of consumer optoelectronics.