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

Electrolyte-gated transistors (EGTs) have emerged as promising electronic devices owing to their remarkable electrical performance. In the case of the EGTs with a polymer semiconductor, the electrical properties of devices are affected by the formation of an electric double layer and electrochemical doping at the electrolyte–channel interface. Here, poly(3-hexylthiophene) (P3HT)–insulating polymer blend films were developed to utilize as a channel layer in EGTs, and the electrochemical doping effect at the interface was investigated. The blend film formed by the spin-coating process from precursor solution showed lateral phase separation, not the vertical. The electrical and structural analyses revealed that the ions can penetrate both the pristine P3HT, and the P3HT-polymer blend in EGTs under applied gate bias. Thus, the transistors with blended film exhibited typical electrochemical doping features such as low contact resistance, high drain current, and low operation voltage. By optimizing the process condition, the device based on P3HT-polymer blend films shows average transistor mobility of 1.07 cm2·V–1 s–1 and threshold voltage of −0.29 V, which is comparable with that obtained from the pristine P3HT-based EGTs. This study could provide helpful guidance for the design and optimization of individual transistors and their complementary circuits.