Chiroptical organic heterojunction synaptic phototransistor exhibiting near-theoretical limit asymmetry factor for neuromorphic cryptography

Advancing organic photoelectric synapses for circularly polarized light (CPL) detection poses challenges in balancing CPL discrimination and photoelectric conversion efficiency. In this study, we reveal an innovative heterojunction consisting of two-dimensional molecular crystal (2DMC) and cholesteric liquid crystal network (CLCN) film to achieve high-performance CPL-resolved synapses. The periodically ordered molecular packing and molecular-scale thickness of 2DMC amplify the efficient exciton dissociation, consequently endowing the synaptic phototransistor with exceptional responsivity of 3.45 × 10⁴ A W⁻¹. Harnessing the intrinsic chiroptical of the CLCN film on the 2DMC, the device manifests a distinguished synaptic response to CPL stimuli, as substantiated by a significant dissymmetry factor of 1.97. Furthermore, the binary output states corresponding to distinct excitatory postsynaptic current levels facilitate robust chiroptical data encoding and encryption. Our innovative integration within polarized neuromorphic vision bolsters the capabilities of photonic devices and ushers in new frontiers for secure visual data encoding and transmission.