PbS colloidal quantum dots imagers: From single devices to arrays, flexible platforms, and CMOS‐integrated systems

Abstract

Imagers operating in the visible to near‐infrared (NIR) range play an important role in applications such as industrial sorting, security surveillance, and autonomous driving. However, conventional imaging technologies based on silicon and III–V semiconductors suffer from several limits, including restricted spectral range, high fabrication cost, and complicated integration processes, which limit their large‐scale use. Lead sulfide (PbS) colloidal quantum dots (CQDs) have been explored as an alternative material system, because their bandgap can be tuned by size, they can be processed from solution at low cost, and they are compatible with monolithic integration approaches that avoid flip‐chip bonding. This review summarizes recent progress in PbS CQD imagers, with a focus on device‐level optimization methods, including band structure design, defect passivation, and interface control, and this review discusses recent work on the monolithic integration of PbS CQDs with flexible substrates, silicon platforms, and CMOS readout integrated circuits, which provides an effective way to reduce the cost and system complexity of traditional infrared imagers. Finally, this review presents recent developments in CQD synthesis and briefly considers their relevance to optical bioimaging, neuromorphic and synaptic devices, and artificial intelligence‐based recognition.