Diketopyrrolopyrrole-Porphyrin Based Conjugated Polymers for Ambipolar Field-Effect Transistors

Porphyrin-based molecules have been widely used in dye-sensitized solar cells and bulk heterojunction solar cells, but their application in field-effect transistors (FETs) is limited. In this work, two conjugated polymers based on diketopyrrolopyrrole and porphyrin units were developed for FETs. The polymers exhibit extra-low band gap with energy levels close to -4.0 eV and -5.0 eV due to the strong electron-donating and withdrawing ability of porphyrin and diketopyrrolopyrrole. With additionally high crystalline properties, ambipolar charge carrier transports with a hole mobility of 0.1 cm²  V^-1  s^-1 in FETs were realized in these polymers, representing the highest performance in solution-processed FETs based on porphyrin unit.