Dual-Band Infrared PbS Colloidal Quantum Dot Focal Plane Array

Near-infrared and short-wave infrared dual-band detection has emerged as a pivotal enabling technology in across diverse applications spanning material identification, biological diagnostics, and machine vision. Current dual-band device architectures based on vertically stacked photodetectors such as those employing two-dimensional materials or back-illuminated colloidal quantum dots remain constrained by limited large-area manufacturability and incompatibility with standard readout integrated circuits. Here, we report a top-illuminated p-i-n-i-p dual-band photodetector using two distinct sizes of solution-processed PbS colloidal quantum dots, which enables bias-switchable spectral response between near-infrared and short-wave infrared regimes. The device achieves a specific detectivity exceeding 1×1011 cm·Hz1/2·W−1 in both bands, with short-wave infrared crosstalk of 0.5% and near-infrared crosstalk of 7.7%. The successful fabrication of a monolithic integrated 128×128 dual-band focal plane array showcases a functional dual-band infrared imager. This work establishes a scalable and silicon-compatible platform toward high-performance, low-cost dual-band infrared imagers. Di et al. report a dual-band infrared photodetector employing size-engineered PbS quantum dots as spectrally selective absorbers in a unipolar barrier configuration, which can switch between near- and short-wave infrared region. A 128×128 focal plane array is prepared for practical infrared multispectral imaging.