Pyrroloindacenodithiophene polymers: the effect of molecular structure on OFET performance

The synthesis, characterization and testing of four novel pyrroloindacenodithiophene (NIDT) copolymers, in organic field effect transistor (OFET) devices, is reported. Copolymerization of thiophene, thienothiophene, thienopyrrolodione and diketopyrrolopyrrole with NIDT, to form alternating copolymers, is described. Two-dimensional Grazing Incidence Wide Angle X-ray Diffraction (2D GIWAXD) is used to probe the thin film molecular structure and, together with DFT studies, help to explain why the diketopyrrolopyrrole containing polymer outperforms the others in terms of hole transport, exhibiting an average mobility of 0.01 cm2 V−1 s−1.