Infrared colloidal quantum dots for photoelectric conversion devices

Abstract

In recent years, colloidal quantum dots (CQDs) have been widely used in optoelectronic devices due to their advantages including low cost, solution processability, substrate compatibility, and easily tuned photoelectric characteristics via the quantum size effect. However, there are several factors still limiting the further improvement of performances for CQD optoelectronic devices: (1) the incomplete surface passivation of CQDs; (2) a trade-off between absorption and photogenerated carrier collection; and (3) the poor air stability. This review focuses on the methods for performance improvement of CQD-based photoelectric conversion devices including photovoltaic solar cells and photodetectors. Taking CQD solar cells as an example, different surface passivation methods are summarized. To increase the separation and collection of photogenerated carriers, the device architecture is optimized by aligning the energy band and broadening the depletion width. Additionally, device performance can be further enhanced through interface modification which could decrease recombination. In the next section, recent progress in the development of CQD near-infrared (NIR), short-wave infrared (SWIR), and mid-wave infrared (MWIR) photodetectors is reviewed. To overcome the traditional photodetection limitations posed by the dark current/sensitivity/bandwidth trade-off, innovative device architectures are developed. Finally, this review discusses the application of CQD photodetectors in infrared imaging.