Assessing the Potential and Limitations of PbS and HgTe Colloidal Quantum Dot Infrared Detectors for Free Space Optical Communication

Free space optical communication with infrared light is a promising secure wireless optical communication technology, where infrared photodetectors are the core component. To date, such applications are based on epitaxial growth narrow-band semiconductors facing the challenge of large-area fabrication. Infrared colloidal quantum dots (CQDs) are of interest because of the high-throughput solution processing. Here, large-area CQD photodetectors with adjustable wavelengths covering 1.3–2.0 µm. For 1 × 1 mm² CQD photodetector, the response time achieved within 1 µs at room temperature, responded sharply to the 25 kbps PRBS-7 communication code is demonstrated. For 1.5 × 1.5 cm² large-area CQD photodetectors, a communication rate of 2 kbps is achieved. This work is a step toward the CQD application in the field of optical communications.