Eliminating Nonideal Transfer Characteristics of Polymer Field-Effect Transistors by Isoindigo-Based Molecular Electron Acceptors

High-mobility organic field-effect transistors (OFETs), particularly those based on donor–acceptor polymers, often exhibit nonideal transfer characteristics, limiting their practical applications. Doping these semiconductors with specifically designed organic molecular electron acceptors can effectively address these deficiencies. By employing isoindigo-based acceptors with appropriate electron-withdrawing groups as dopants in diketopyrrolopyrrole-thienothiophene-based OFETs, we achieve an outstanding transistor performance with ideal transfer characteristics. Comprehensive analyses using ultraviolet–visible absorption, X-ray diffraction, ultraviolet photoelectron spectroscopy, and electrical measurements demonstrate that p-dopants play crucial roles in enhancing electron transfer, reducing charge carrier traps, and lowering contact resistance, thereby eliminating the typical “double slope” and hysteresis in OFET transfer characteristics.