Organic electronic synapses with pinched hystereses based on graphene quantum-dot nanocomposites

Organic electronic synapses (e-synapses) based on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/graphene quantum dot (GQD) nanocomposites are fabricated by using a solution method. Current–voltage (I–V) curves for the devices under dual positive bias voltage sweeps show that the conductance with a pinched hysteresis gradually increased with increasing applied voltage, and those for the devices under dual negative bias voltage sweeps gradually decreased with increasing applied voltage, indicative of the fingerprint of e-synapses. The current in the devices decreases with increasing concentration of GQDs in the active layer, and the devices fabricated utilizing the ratio of PEDOT:PSS to GQDs of 1:0.4 shows the best performance among the e-synapses. The carrier transport and operating mechanisms of the e-synapses are described on the basis of both the I–V results and the trapping and escape of electrons from the GQDs. An electronic device made from organic materials that behaves like a synapse in the brain has been created by scientists in Korea. Engineering electronic components that mimic the behavior of synapses could revolutionize the currently silicon-based computing industry. Tae Whan Kim and co-workers from Hanyang University combined graphene quantum dots with an electronic polymer to create what could be the building block of a computer that operates like the brain. They made a type of artificial synapse known as a resistive switch, or memristor, that can be controllably flipped between a high and low electrical resistance states. The researchers' device consisted of graphene quantum dots embedded in poly(3,4-ethylenedioxythiophene) polystyrene sulfonate. They showed that its electrical properties can be optimized by changing the concentration of quantum dots. Organic electronic synapses based on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/graphene quantum-dot (GQD) nanocomposites were fabricated by using a solution method. Current–voltage (I–V) curves for the devices under dual positive bias voltage sweeps and under dual negative bias voltage sweeps showed that the conductance with a pinched hysteresis gradually increased and gradually decreased, respectively, with increasing applied voltage which is a fingerprint of e-synapses. The current in the devices was found to decrease with increasing concentration of GQDs in the active layer, and the devices fabricated utilizing the ratio of PEDOT:PSS to GQDs of 1:0.4 showed the best performance among the e-synapses. The carrier transport and operating mechanisms of the e-synapses are described in this paper on the basis of both the I–V results and the trapping and escape of electrons from the GQDs. We believe that our letter contains significant results of interest to a broad spectrum of NPG Asia Materials readers.