Revealing the Effect\nof Crystalline Self-Assembled\nMonolayer in Biomimetic Photosynapse with Ultraviolet Light Protection\nCapability

The research on photonic synapses holds immense promise\nfor various\napplications, such as robotics and artificial intelligence. Pursuing\nlightweight, miniaturized, and low-energy consumption designs is crucial\nfor enhancing efficiency and adaptability in evolving technological\nenvironments. To achieve this goal, this work designs a series of\nconjugated self-assembled molecules with photoactive pyrene, benzo-naphthol-thiophene\n(BNT), perylene, and benzothieno-benzothiophene cores to develop ultrathin\n(<3 nm) charge-trapping self-assembled monolayers (SAMs). The highly\ncrystalline BNT forms an orderly arrangement with the semiconducting\nchannel, further exhibiting distinguished current contrast stability\n(∼10<sup>8</sup>) and synaptic features, including paired-pulse\nfacilitation (153%), ultralow energy consumption (28.9 aJ), and short/long-term\nplasticity. The device successfully demonstrates the emulation of\nhuman learning behavior and the self-protection mechanism against\nultraviolet radiation utilizing crystalline and conjugated SAMs with\ndifferent charge traps. Additionally, the capability of background\ndenoising is evidenced by the high recognition accuracy (∼90%)\nfor the preprocessed images. This study not only strengthens the diverse\nfunctionality of SAMs in optoelectronic devices but also highlights\nthe significant potential of device miniaturization for biomimetic\napplications, making it a crucial contribution to the field.