Nonorthogonal Solvent Effects in 2,7-Dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) Thin-Film Transistors

Thin-film transistors (TFTs) using 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) organic small-molecule semiconductors represent a significant advancement in the field of organic and flexible electronics. Their high charge carrier mobility, solution processability, and tunable electronic properties make them highly suitable for diverse device applications. In this study, we report the effects of nonorthogonal solvents on the performance of C8-BTBT TFTs by exploring the functional impact of the choice of gate dielectric and device configuration. By considering the crucial semiconductor/dielectric interface effect for developing operational TFTs, we investigated different C8-BTBT TFTs gated by oxide, solution-processed polymer, and polymer electrolyte gate dielectrics. The optimized devices achieved varied charge carrier mobilities between 10^-3 and 18 cm² V^-1 s^-1, which were within the reported mobilities for C8-BTBT TFTs in the literature. This work provides a practical insight into nonorthogonal solvent effects and lays a foundation for developing high-performance TFTs and electronic devices using organic small-molecule semiconductor materials.