Ultrafast Responsive and Low-Energy-Consumption Poly(3-hexylthiophene)/Perovskite Quantum Dots Composite Film-Based Photonic Synapse

Emulation of photonic synapses through photo-recordable devices has aroused tremendous discussion owing to the low energy consumption, high parallel, and fault-tolerance in artificial neuromorphic networks. Nonvolatile flash-type photomemory with short photo-programming time, long-term storage, and linear plasticity becomes the most promising candidate. Nevertheless, the systematic studies of mechanism behind the charge transfer process in photomemory are limited. Herein, the physical properties of APbBr₃ perovskite quantum dots (PQDs) on the photoresponsive characteristics of derived poly(3-hexylthiophene-2,5-diyl) (P3HT)/PQDs-based photomemory t hrough facile A-site substitution approach are explored. Benefitting from the lowest valance band maximum and longest exciton lifetime of FAPbBr₃ quantum dot (FA-QDs), P3HT/FA-QDs-derived photomemory not only exhibits shortest photoresponsive characteristic time compared to FA_0.5Cs_0.5PbBr₃ quantum dots (Mix-QDs) and CsPbBr₃ quantum dots (Cs-QDs) but also displays excellent ON/OFF current ratio of 2.2 upon an extremely short illumination duration of 1 ms. Moreover, the device not only achieves linear plasticity of synapses by optical potentiation and electric depression, but also successfully emulates the features of photon synaptic such as pair-pulse facilitation, long-term plasticity, and multiple spike-dependent plasticity and exhibits extremely low energy consumption of 3 × 10^?17 J per synaptic event.