A Path Toward Making Mid-Wave Infrared Sensing a Ubiquitous Technology

Reducing the size, weight, power consumption, and cost of infrared detectors can make the use of infrared sensing ubiquitous. In the technologically important spectral region of mid-wavelength infrared (MWIR = 3 - 5 μm), commercially available detectors suffer from the high cost associated with epitaxial growth and hybridization as well as the stringent requirement for cryogenic cooling, limiting their use to defense and space applications. The colloidal quantum dot is one of the potential materials candidate to overcome these limitations due to the availability of low-cost synthesis and wafer-scale device fabrication via solution processing. Infrared sensors based on colloidal quantum dots have been studied for decades, and harnessing the interband transition in these quantum-confined nanostructures has been the mainstream theme in optoelectronic research. More unique photophysical properties can be harnessed by utilizing the transitions within the conduction levels or valence levels, known as intraband (intersubband) transitions. In this presentation, we discuss the progress, challenges, and opportunities of MWIR sensors fabricated from Ag₂Se intraband colloidal quantum dots, a heavy metal-free colloidal nanomaterial that has merits for wide-scale adoption in consumer and industrial sectors.