Electron Trapping Enhanced Deep-Ultraviolet Optoelectronic Synapses Based on Two-Dimensional Wide-Bandgap Perovskite/Organic-Semiconductor Heterojunctions

Deep-ultraviolet (DUV) optoelectronic synapses (OSPs) are core components of next-generation biometric recognition systems. While devices based on inorganic wide-bandgap (WB) semiconductors achieved admirable synaptic performance, critical challenges still exist. Herein, we present low-temperature and solution-processable visible-blind DUV OSPs composed of two-dimensional WB perovskite/organic semiconductor vertical heterojunctions. By leveraging the electron trapping effect to spatially separate photoexcited electrons and holes, we can significantly enhance the persistent optoelectronic conductivity, enabling remarkably improved synaptic performance. An optimal device holds outstanding synaptic properties with improved short- to long-term memory capabilities. Importantly, it operates with an extremely low power consumption of 28.7 fJ per synaptic event, rivaling the energy efficiency of biological synapses (1-100 fJ). Finally, the device is successfully applied in a DUV fingerprint recognition system to preprocess fingerprint data, revealing an accuracy as high as 96.7%. This study lays the foundations for the design of high-performance, low-cost, and low-power DUV OSPs toward biometric recognition utilizations.