Polyzwitterion with Imidazole for Ultralow-Power Organic Photoelectric Synaptic Transistors Achieving Multicolor...

Neuromorphic in-sensor vision demands photoelectric synaptic transistors that co-localize optical sensing and electrically tunable plasticity in a compact device, thereby simplifying artificial visual sensing circuits. Electrolytes and ionic liquids are widely employed as dielectric layers for neuromorphic transistors; however, cation-anion pairs without covalent bonds typically suffer from ion-migration, ion replacement, and electrochemical reactions. These processes lead to current leakage, elevated power consumption, and irreversible drift, while photo-modulation is further attenuated by exciton-polaron quenching. Here, to stabilize ionic charges and suppress ion-migration, a polyzwitterion, poly(3-(1-vinyl-3-imidazolyl)-propanesulfonate), is used as a single medium to unify electro- and photo-synaptic functions, thereby simplifying the components and interfaces of the multilayer device. The aromatic conjugated imidazole ring stabilizes the cationic charge, and the covalently tethered cation-anion pair prevents long-distance ion-migration, ensuring strong cation-anion dipole polarization and reversible charge trapping. This enables robust multi-wavelength photo-synaptic modulation coupled with electro-synaptic plasticity. The resulting organic photoelectric synaptic transistors achieve ultralow event energy consumption down to 10.95 aJ and support application-relevant in-sensor demonstrations, including encrypted image decoding, color-guided robotic manipulation, pedestrian-speed recognition, and motion prediction. These findings are poised to accelerate the development of multifunctional photoelectric synaptic devices and integrated sensing-computing hardware architectures for artificial visual systems.