Lead-Free Perovskite\nPhotodetectors for Fast Fourier\nSingle-Detector Imaging

In\nthe pursuit of high-resolution imaging, the expense\nof conventional\nsilicon photodiode arrays poses a significant challenge. To address\nthis issue, we present a novel imaging approach using a single-detector\ncamera based on a fast Fourier transform (FFT) technique. Our system\nuses an optimized single Cs<sub>3</sub>Bi<sub>2</sub>Br<sub>9</sub> photodetector (PD) as a light receiver, achieving a high-resolution\n256 × 256-pixel image within 130 s with a low sampling rate of\n3.8% and surpassing that of other perovskite imagers. By double-side\ninterfacial engineering, an optimized Cu<sub><i>x</i></sub>O/Cs<sub>3</sub>Bi<sub>2</sub>Br<sub>9</sub>/PCBM/BCP (CCPB) PD exhibits\nsignificant enhancement in the response speed and on/off ratio by\n9333 and 503 times, respectively. These improvements are attributed\nto the synergistic effects of the ultrathin CuO<sub><i>x</i></sub> interfacial layer and the spin-coated BCP layer, which form\nwell-matched energy-band alignments with perovskites. Our findings\nsuggest that the double-sided interface engineering strategy can be\nextended to other high-exciton binding energy Bi-based perovskites\nand their applications, potentially revolutionizing the field of digital\nimaging by providing a cost-effective alternative to traditional high-resolution\nsensors.