Bias-Tunable Two-Terminal Organic Photodetector for Intelligent Imaging

Image sensors capable of in-sensor computing can substantially reduce computational burdens in machine vision systems that require extensive data post-processing. Reconfigurable photodetectors, which serve as the fundamental building blocks for such sensors by enabling pixel-level signal modulation, are therefore central to this development. They have been explored using emerging materials or modified field-effect transistor architectures, but their complex structures and processing limit scalability and resolution. Here we report a reconfigurable photodetector with a simple, vertically stacked two-terminal structure based on an organic donor/acceptor/donor tri-layer active, which functions equivalently as dual photodiodes connected with opposite polarity with a resistor inserted between them. The device exhibits 80 dB linear dynamic range and, furthermore, features responsivity that can be tuned in a quasi-linear fashion from -26 mA/W to 77 mA/W under operation bias from -1 V to 1 V. This continuously variable responsivity can act as weight values in a neural network, as demonstrated with a 4 × 4 photodetector array that performed reconfigured photocurrent map generations and kernel operations, emulating simple image preprocessing filters. Its voltage-controlled tunability and straightforward fabrication process underscore the potential for monolithic integration with various backplane technologies, paving the way toward compact and efficient intelligent image sensors.