High-mobility and solution-processable organic field-effect transistors based on carbazole-dihexylquaterthiophenes with controllable morphology

An oligomeric semiconductor based on bithiophene-carbazole-bithiophene as called DH4T-Cz were prepared and applied in solution-processable organic field-effect transistors (OFETs). The thermal, optical, and electrochemical properties of DH4T-Cz were fully studied with TGA, DSC, UV–Vis, photoluminescence (PL), and cyclic voltammetry (CV). The thin film morphologies of deposited-DH4T-Cz via different deposition techniques were also investigated with POM and XRD to figure out the relationship of the corresponding deposition process. After fabricating the OFETs, a relative higher hole mobility was observed in 0.5 cm2 V−1 S−1 with dip-coating deposition at specific dipping speed due to the higher ordered molecular packing and uniform microribbon orientation. The dip-coating process of DH4T-Cz could be considered a large-area and continuous fabrication for OFET, and the performance is highly competent to the high-end OFET application.