Ion-Gating Engineering of Organic Semiconductors toward Multifunctional Devices

Ion-gating engineering provides a new way to bridge electronics and ionics, and more importantly, bringing unprecedented opportunities for organic semiconductors (OSCs) based bioelectronics and solid-sate physics. Compared with conventional-dielectric gating, ion gating shows unique features in an extremely large electric field, high transconductance, low operating frequency, and ultrahigh carrier concentration. It therefore boosts the rapid development of different organic devices, including neuromorphic devices and amplifying transducers, and offers a powerful strategy to probe the charge transport, thermoelectric and even superconducting properties of organic materials at different scales. In this review, first, the fundamental mechanism of ion gating is discussed to enable multifunctional devices. The electrolyte materials and organic semiconductors are also summarized that are widely used in ion-gated devices and their associated properties are examined. Moreover, key concepts of manipulating ion-electron coupling are highlighted for opening up new frontiers in organic multifunctional electronics. Finally, the challenges and perspectives on the ion gating of OSCs are proposed to highlight the directions that deserve attention in this emerging interdisciplinary field.