Surface-tailored graphene channels

Abstract The detection of ions and molecules in liquids has been receiving considerable attention for the realization of the electronic tongue. Solution-gated field-effect transistors (SFETs) with high sensitivity are useful for detecting ions and molecules by reading electrical transconductance. However, to date, ionic and molecular sensors that employ SFETs have limitations, such as the lack of a dynamic on–off function and low selectivity. In this study, we evaluate rationally designed graphene SFETs as pH and glucose-selective sensors. The integration of the microfluidic channel to the graphene SFET exhibits dynamic on–off functions by controlling injection and withdrawal of solutions. The graphene SFET device exhibits high pH and glucose selectivity when coated with Nafion as a molecular sieve and Au-decorated nanoparticles as receptors, respectively. The dynamic on–off functions and high selectivity of SFETs with tailored graphene channels have a high potential for advancing as a platform for electronic tongues by integrating the separate SFETs as an array for simultaneous sensing of multiple targets.