Silver-Adapted Diffusive Memristor Based on Organic Nitrogen-Doped Graphene Oxide Quantum Dots (N-GOQDs) for Artificial Biosynapse Applications

Carbon-based electronic devices are suitable candidates for bioinspired electronics due to their low cost, eco-friendliness, mechanical flexibility, and compatibility with complementary metal-oxide-semiconductor technology. New types of materials such as graphene quantum dots (GQDs) have attracted attention in the search for new applications beyond solar cells and energy harvesting due to their superior properties such as elevated photoluminescence, high chemical inertness, and excellent biocompatibility. In this paper, a biocompatible/organic electronic synapse based on nitrogen-doped graphene oxide quantum dots (N-GOQDs) is reported, which exhibits threshold resistive switching via silver cation (Ag+) migration dynamics. In analogy to the calcium (Ca2+) ion dynamics of biological synapses, important biological synapse functions such as short-term potentiation (STP), paired-pulse facilitation, and transition from STP to long-term plasticity behaviors are replicated. Long-term depression behavior is also evaluated and specific spike-timing dependent plasticity is assessed. In addition, elaborated switching mechanism of biosimilar Ag+ migration dynamics provides the potential for using N-GOQD-based artificial synapse in future biocompatible neuromorphic systems.