Organic electrochemical transistors with graphene-modified gate electrodes for highly sensitive and selective dopamine sensors.

Organic electrochemical transistors (OECTs) are successfully used as highly sensitive and selective dopamine sensors. The selectivity of the OECT-based dopamine sensors is significantly improved by coating biocompatible polymer Nafion or chitosan on the surface of the gate electrodes. The interference induced by uric acid and ascorbic acid is effectively eliminated especially after the modification of Nafion. The sensitivity of the devices is improved by graphene flakes co-modified on the gate electrodes. The detection limit of the devices to dopamine is down to 5 nM, which is much lower than that of conventional electrochemical approaches. Because the OECT-based dopamine sensors are solution processable, they are suitable for low-cost and disposable sensing application.