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.