Tailoring Functional Interlayers in Organic Field-Effect Transistor Biosensors

This review aims to provide an update on the development involving dielectric/organic semiconductor (OSC) interfaces for the realization of biofunctional organic field‐effect transistors (OFETs). Specific focus is given on biointerfaces and recent technological approaches where biological materials serve as interlayers in back‐gated OFETs for biosensing applications. Initially, to better understand the effects produced by the presence of biomolecules deposited at the dielectric/OSC interfacial region, the tuning of the dielectric surface properties by means of self‐assembled monolayers is discussed. Afterward, emphasis is given to the modification of solid‐state dielectric surfaces, in particular inorganic dielectrics, with biological molecules such as peptides and proteins. Special attention is paid on how the presence of an interlayer of biomolecules and bioreceptors underneath the OSC impacts on the charge transport and sensing performance of the device. Moreover, naturally occurring materials, such as carbohydrates and DNA, used directly as bulk gating materials in OFETs are reviewed. The role of metal contact/OSC interface in the overall performance of OFET‐based sensors is also discussed. Biomaterials are successfully integrated in OTFT devices as biorecognition elements to develop ultrasensitive label‐free electronic biosensors or as gating materials to obtain high‐performance devices.