Yunxiang Di, Kun Ba, Lingfeng Ye, Qianru Zhao, Xingyu Qi, Weiyi Tang, Hanting Wang, Yi Long, Yan Chen, Xudong Wang, Zhangcheng Huang, Shenyang Huang, Yun Tong Tang, Tie Lin, Hong Shen, Xiangjian Meng, Hugen Yan, Qi Liu, Jianlu Wang, Junhao Chu, Ming Liu
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.