Graphene-based materials and their applications in electrolyte-gated transistors for sensing

Graphene is a two-dimensional material with remarkable physicochemical characteristics. In particular, gra-phene is highly sensitive to its electronic and electrostatic environment. For these reasons, among various ap-plications of graphene, its use as a sensitive material in field-effect transistors (FETs) is widely studied, especially for biodetection purposes. So, this review aims to introduce the reader to the state of the art of graphene-based materials for their applications in electrolyte-gated graphene field-effect transistors (EGGFETs) for biosensing applications. Among numerous ways to produce graphene-based materials for such devices, some of the most important, widely used methods are presented herein. After that, the working principle of graphene-based FETs is discussed and the various ways to tune graphene's electronic properties are presented. The fabrication methods are discussed, with an emphasis on inkjet printing which allows printing of EGGFETs from aqueous graphene oxide inks, providing that it is subsequently reduced to adjust the mobility of charge carriers and the doping state. Finally, some of the recent works concerning the use of FETs in biosensing applications are reviewed.