Poly(3-Hexylthiophene)-Insulating Polymer Binary Blends-Based\nElectrolyte Gated Transistors

Electrolyte-gated\ntransistors (EGTs) have emerged as promising\nelectronic devices owing to their remarkable electrical performance.\nIn the case of the EGTs with a polymer semiconductor, the electrical\nproperties of devices are affected by the formation of an electric\ndouble layer and electrochemical doping at the electrolyte–channel\ninterface. Here, poly­(3-hexylthiophene) (P3HT)–insulating polymer\nblend films were developed to utilize as a channel layer in EGTs,\nand the electrochemical doping effect at the interface was investigated.\nThe blend film formed by the spin-coating process from precursor solution\nshowed lateral phase separation, not the vertical. The electrical\nand structural analyses revealed that the ions can penetrate both\nthe pristine P3HT, and the P3HT-polymer blend in EGTs under applied\ngate bias. Thus, the transistors with blended film exhibited typical\nelectrochemical doping features such as low contact resistance, high\ndrain current, and low operation voltage. By optimizing the process\ncondition, the device based on P3HT-polymer blend films shows average\ntransistor mobility of 1.07 cm<sup>2</sup>·V<sup>–1</sup> s<sup>–1</sup> and threshold voltage of −0.29 V, which\nis comparable with that obtained from the pristine P3HT-based EGTs.\nThis study could provide helpful guidance for the design and optimization\nof individual transistors and their complementary circuits.