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.
Chang et al. (Mon,) studied this question.