Switchable dual-band photodetector based on PbS colloidal quantum dots for multispectral short-wavelength infrared imaging

In this work, we present a photodetector based on PbS colloidal quantum dots which can be used for low-cost, high-resolution multispectral imaging in the short-wavelength infrared range. Using versatile solution-based processing of thin films, we fabricated a switchable, dual-channel, two-terminal photodetector that can be monolithically integrated with small-pitch CMOS readout arrays. Its vertically stacked structure provides higher spatial resolution compared to conventional snapshot multispectral image sensors. We show the results of the optical simulations based on the transfer matrix method, which allowed us to achieve a wavelength-tunable narrowband response. We demonstrate the operation of the photodetector and its facile tunability by showing an EQE of more than 25% at different bands in the wavelength range of 1-1.5 μm. This work demonstrates the potential of the emerging thin-film technology for multispectral imaging.