This report presents an overview on the field of semiconductor nanocrystals, and on their use as the active media in infrared photodetectors. In present days, due to the high cost and low throughput of the techniques for the production of state-of-the-art detectors based on bulk materials or heterostructures, infrared sensing remains limited to few niche applications like astronomy, defense and research. Lately, a new class of materials, has emerged as a promising candidate to be the new go-to active layer in infrared detectors. Colloidal quantum dots exhibit extraordinary properties, among which the band gap tunability, the solution processability and the silicon compatibility, which have raised the interest of the scientific community on the potential employment of this new technology for the production of low-cost sensors.