Usta, HakanFacchetti, A. F.2025-09-252025-09-25201597835273363959783527679973https://doi.org/10.1002/9783527679973.ch1https://hdl.handle.net/20.500.12573/4431This chapter reviews the achievements in the development of molecular and polymeric semiconductors for charge transport in thin-film transistors (TFTs). In particular, it introduces the basic concepts of organic semiconductor structure and organic thin-film transistor (OTFT) operation and then focuses on initial studies and works. Organic semiconductors for OTFTs must possess two essential structural features for their successful implementation in printed electronics. The first feature is a π-conjugated core/chain composed of linked unsaturated units. The second feature is core functionalization with solubilizing substituents, which is essential for inexpensive manufacture by solution methods as well as for enhancing solid-state core interactions. There are several advantages in using polymeric versus molecular p-conjugated semiconductors. Isoindigo has become a popular conjugated moiety in polymer semiconductor design because of its strong electron-withdrawing character. Polymeric p-channel TFTs have reached new heights, with hole mobilities unthinkable only few years back and surpassing 10 cm2V-1 s-1. © 2018 Elsevier B.V., All rights reserved.eninfo:eu-repo/semantics/closedAccessIsoindigoOrganic SemiconductorOrganic Thin-Film Transistor (Otft)P-Conjugated SemiconductorsPolymeric SemiconductorsConjugated PolymersOrganic Field Effect TransistorsSemiconducting Organic CompoundsSemiconducting PolymersThin Film CircuitsThin FilmsElectronwithdrawingIsoindigoOrganic Thin Film TransistorsPolymer SemiconductorsPolymeric SemiconductorsPrinted ElectronicsSemiconductor StructureThin Film Transistors (Tfts)Thin Film TransistorsBook Part10.1002/9783527679973.ch12-s2.0-85017302422