文摘
We report a series of benzotriazole-based semicrystalline 蟺-conjugated polymers with noncovalent conformational locks for applications in polymer field-effect transistors. The benzotriazole moiety is a versatile electron-deficient building block that offers two chemically functionalizable sites, 2(N) and 5, 6(C) positions, allowing easy modulation of the solution processability and electronic structures of the resulting polymers. Fluorine or alkoxy substituents were introduced to the benzotriazole unit to enhance the molecular ordering through intra- and intermolecular F路路路S, F路路路H鈥揅, C鈥揊路路路蟺F, or S路路路O attractive interactions. The fluorinated polymer (PTBTz-F) showed remarkably enhanced hole mobility (渭h = 1.9 cm2/(V路s), on/off ratio = 8 脳 107) upon thermal annealing at 305 掳C, compared to the unsubstituted one (PTBTz) (渭h = 7.0 脳 10鈥? cm2/(V路s), on/off ratio = 3 脳 106). Alkoxy unit substitution (PTBTz-OR) also improved the carrier mobility up to 0.019 cm2/(V路s) with an on/off ratio of 4 脳 105. Fluorine or alkoxy substitution induced tight interchain ordering with edge-on orientation, as confirmed by X-ray diffraction measurements. In particular, fluorinated PTBTz-F showed high thermal stability (Td 453 掳C) and the remarkable device characteristics with deep frontier orbital levels.