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In Advanced materials (Deerfield Beach, Fla.)

Neuromorphic engineering and artificial intelligence demands hardware elements that emulates synapse algorithms. During the last decay electrolyte-gated organic conjugated materials have been explored as a platform for artificial synapses for neuromorphic computing. Unlike biological synapses, in current devices the synaptic facilitation and depression are triggered by voltages with opposite polarity. To enhance the reliability and simplify the operation of synapse without lowering its sophisticated functionality, here we have devised an electrochemical-electret coupled organic synapse (EECS) possessing a reversible facilitation-to-depression switch. Electret charging counterbalances channel conductance changes due to electrochemical doping, inducing depression without inverting the gate polarity. Overall, EECS functions as a threshold-controlled synaptic switch ruled by its amplitude-dependent, dual-modal operation, which can well emulate information storage and erase as in real synapses. By varying energy level offset between channel material and electret, the EECS's transition threshold can be adjusted for specific applications, e.g. imparting additional light responsiveness to the device operation. Our novel device architecture represents a major step forward in the development of artificial organic synapses with increased functional complexity and it opens new perspectives towards the fabrication of abiotic neural networks with higher reliability, efficiency and endurance. This article is protected by copyright. All rights reserved.

Wang Hanlin, Chen Yusheng, Ni Zhenjie, Samorì Paolo


(organic synapses, electrochemical doping, facilitation-to-depression transition, neuromorphic devices), organic electret memory, polyelectrolyte-gated organic transistors