Charge transport in organic field-effect transistors

Understanding the charge transport physics is crucial for improving organic field-effect transistors (OFETs) performance. Diverse mobility behaviour has been discovered and numerous theories have been established to explain the nature of charge transport in OFETs. In this review, the theories are divided into three groups, bandlike theories, transient localization models, and hopping transport. The relationship between structural properties and intrinsic charge transport physics will be discussed. The fundamental assumptions and theoretical framework of these models will be introduced and their advantages and limits when describing charge transport in OFETs are also discussed based on recent experimental observations. Band-like theory is more applicable to highly-ordered single crystals while hopping models concentrate on disordered materials. Newly developed transient localization theories emphasize the importance of thermal fluctuations, which hopping theories and band-like models fail to include, attributed to weak van der Waals interactions. We integrate and summarize these theories to provide a more sophisticated understanding and more universal descriptions of the charge transport process to guide further developments and potential applications of OFETs.