Low-Power and Flexible Optoelectronic Synapses Based on P3HT:Y6 Bulk Heterojunctions with Broadband Perception Capability

Flexible artificial synapses featuring broadband perception capabilities and minimal energy dissipation are pivotal for advancing soft or wearable neuromorphic visual systems. Herein, we present the design and construction of a broadband optoelectronic synapse based on a P3HT:Y6 bulk heterojunction. Compatible with both rigid and flexible substrates, this device exhibits robust perceptual capabilities across a broad spectral range from deep-ultraviolet to near-infrared (265-1300 nm) radiation. By tuning the proportion of P3HT and Y6, an optimal device attains enhanced synaptic characteristics with prominent short- to long-term memory capacities. Notably, the near-infrared perception capability beyond the intrinsic optical absorption range of the two components is enabled by intermolecular charge transfer between them. Crucially, both rigid and flexible synapses hold ultralow energy consumption down to 0.113 fJ per synaptic event, surpassing the efficiency of biological synapses (1-100 fJ). The flexible device further displays an exceptional mechanical robustness and bending durability. Leveraging the outstanding synaptic properties, the device was successfully implemented in optoelectronic reservoir computing, achieving a recognition accuracy of 100% for dynamic trajectory recognition. The present synaptic device may find potential application in emerging neuromorphic visual systems requiring low power, flexibility, and broadband apperceiving ability.