Endogenic ion–electron coupling effect in rGO–Fe2O3 heterostructure for optoelectronic neuromorphic memcapacitor

Taking inspiration from biological synapses, memcapacitors communicating in the ionic language gain more spotlight for neuromorphic computing. However, creating an ion-based memcapacitor that is sensitive to external light signals based on the hysteretic ion transport still remains in the initial stage. Herein, we propose an Ag/rGO–Fe2O3/PVA–H3PO4/Ag memcapacitor with H+ as active ions, in which localized photogenerated electrons originating from Fe2O3 induce the endogenic ion–electron coupling effect with H+ at the rGO, resulting in the weak hydrogen bonds. After removing the light stimuli, these hydrogen bonds will lead to a part of H+ trapped in the rGO layers and the observed hysteretic capacitance. A high accuracy of more than 92.0% is obtained in digital recognition training, which indicates that this endogenic ion–electron coupling effect could be considered as a promising strategy to design the neuromorphic synaptic devices.