High-performance shortwave infrared detection and imaging based on colloidal quantum dots

Colloidal quantum dots (CQDs) have emerged as a promising material platform for short-wave infrared (SWIR) detection and imaging, demonstrating significant potential for applications in information sensing, biomedical imaging, industrial inspection, and consumer electronics. Compared to conventional infrared semiconductors, such as InGaAs and InSb, CQDs exhibit unique advantages, including tunable bandgap, solution-processability, abundant raw materials, and compatibility with scalable manufacturing, enabling substantial cost reduction and ease of integration with existing electronic platforms.This review systematically summarizes recent advances in high-performance CQD-based SWIR photodetectors and imaging systems. Firstly, representative CQD materials covering IV-VI, II-VI, and III-V semiconductor families are analyzed, emphasizing their bandgap tunability, stability, toxicity profiles, and synthesis methodologies. Among these, PbS quantum dots (QDs) have been extensively explored and have achieved the most mature material control and device fabrication techniques, reaching near-industrial readiness.Secondly, the thin-film deposition processes critical to device performance are discussed. The review highlights solid-state and solution-phase ligand exchange methods crucial for converting discrete colloidal particles into highly dense and electrically conductive CQD films. Current approaches, including spin-coating, blade-coating, spray-coating, and inkjet printing, are analyzed, along with post-treatment strategies such as annealing and crosslinking to improve film uniformity, carrier mobility, and overall stability. These advancements have enabled precise control over film morphology and interface properties, significantly enhancing device efficiency and reproducibility.Thirdly, device architectures including photoconductors, photodiodes, and phototransistors are reviewed, with particular focus on photodiodes due to their superior performance in terms of dark current suppression, fast response, and low power consumption. Innovations in interface engineering, such as interfacial passivation, introduction of blocking layers, and heterojunction designs, have effectively reduced dark current densities to sub-nanoampere per square centimeter levels, enabling substantial improvements in signal-to-noise ratio and detectivity (D*).The review also extensively covers the key photodetector parameters, such as external quantum efficiency (EQE), responsivity (R), linear dynamic range (LDR), response speed, and noise characteristics. Recent breakthroughs demonstrate EQE surpassing 80%, responsivities over several amperes per watt, and LDR exceeding 120 dB. Meanwhile, advancements in interface engineering and low-capacitance design have pushed the device response time into the nanosecond regime, significantly broadening the potential application scope to include high-speed optical communications, time-of-flight imaging, and dynamic object tracking.Finally, the integration of CQD photodetectors with CMOS and thin-film transistor (TFT) readout circuits is discussed, showcasing successful demonstrations of SWIR imaging chips. Recent efforts from domestic and international research groups have led to significant milestones, including the realization of the first domestic 640×512 pixel CMOS-integrated PbS CQD imaging chip and innovative vertical stacking strategies for multispectral imaging.In summary, this review provides a comprehensive evaluation of state-of-the-art CQD-based SWIR photodetection and imaging technology, highlighting current achievements, remaining challenges, and future research directions. Continuous development in material chemistry, film processing, device structure optimization, and intelligent system integration is expected to further establish CQDs as a cost-effective and highly capable technology for next-generation infrared imaging applications across industrial, biomedical, consumer, and defense sectors.