In‐Depth Physical Mechanism Analysis of Polymer Artificial Optoelectronic Synapse with High Endurance and Applications of Visual System and Operant Conditioning

Abstract

Abstract Being capable of dealing with both electrical signals and light, artificial optoelectronic synapses are considered to be an important cornerstone of neuromorphic computing. Here, an artificial optoelectronic synapse is reported through a simple solution process using organic poly(3‐hexylthiophene) (P3HT) and a remarkable analog switching characteristic similar to synaptic behavior is observed. The endurance and data retention capability of the P3HT‐based optoelectronic synapse exhibit stable characteristics up to 5000 consecutive cycles and 104 s. Through in‐depth physical mechanism analysis, it is confirmed that the analog switching characteristics of the device are mainly caused by a tunneling mechanism and space charge limited conduction. Furthermore, characterizations such as X‐ray photoelectron spectroscopy and atomic layer deposition prove that the memristive properties of device can be attributed to ion migration. More importantly, the device can co‐modulate the optoelectronic signal and successfully implement a photo‐triggered multi‐signal mode response. Based on this, a 3 × 3 synapse array is developed to demonstrate the potential application of the proposed P3HT‐based optoelectronic synapse in constructing an artificial visual system. Finally, operant conditioning is successfully simulated in the synaptic device. This work provides a reference for the construction of optoelectronic synapses in the neuromorphic visual system.

Keywords

• endurance
• optoelectronic synapses
• organic semiconductors
• solution process
• visual system