Emulating synaptic plasticity with PDMS-Graphite composite memristor

Abstract

• Room temperature-cured PDMS-Graphite composite-based memristors were developed. • Bipolar resistive switching (RS) was observed and conduction mechanism were studied. • Field dependent migration of electrochemically active Ag ions leads to RS. • The devices emulated synaptic characteristics like potentiation and depression. • SRDP and PPF characteristics were also manifested in the fabricated device. Polymer-based memristors are considered as the promising solution, due to their low-cost fabrication route and mechanical flexibility, for wearable neuromorphic systems. Polydimethylsiloxane (PDMS) possesses bio-compatibility, flexibility, and transparency, the essential physicochemical requirement for wearable systems. PDMS-based memristors were fabricated, for the first time, with a device configuration of Ag/composite_polymer/ITO. Here a polymer composite of PDMS and graphite is used as the resistive switching layer. Graphite, being a stable and low cost filler for composite polymers, provides easy tailoring of the electrical properties of switching layer. The current–voltage characteristics show bipolar resistive switching, and charge transport mechanisms were also evaluated. Various synaptic behaviors were emulated for the fabricated PDMS-graphite composite-based memristor. The devices possess potentiation and depression, spike rate-dependent plasticity, and paired-pulse facilitation, which all are the vital characteristics of a biological synapse.