Benzodipyrrolidone-based donor-acceptor semiconducting polymers with high hole mobility and noncovalent conformational locks

Abstract

Constructing highly coplanar polymer backbone plays an important role in boosting the carrier mobility of organic field effect transistors (OFETs) devices. In this study, based on noncovalent conformational locks strategy, we synthesized the electron-acceptor (A) monomer via introducing 3-dodecylthiophene on strong electron-deficient planar benzodipyrrolidone and the electron-donor (D) monomers containing different numbers (0–2) of fluorine atoms at different positon. A series of novel D-A copolymers, namely PBDP-F0, PBDP-F1 and PBDP-F2 with different backbone conformational locks through F⋯S and F⋯H–C noncovalent interactions, were obtained via Stille polycondensation. For the application in an organic field-effect transistor, all the polymers exhibited p-type charge transport characteristics and good performance with the highest hole mobilities as 0.24 cm2 V−1 s−1 for PBDP-F0, 0.87 cm2 V−1 s−1 for PBDP-F1 and 1.93 cm2 V−1 s−1 for PBDP-F2, respectively. AFM and GIXRD investigations indicated that all polymers take predominantly edge-on orientation packing mode because of the rigid and coplanar backbone conformation and the annealing films exhibited small π-π stacking distances of 3.73, 3.71 and 3.69 Å for PBDP-F0, PBDP-F1 and PBDP-F2 respectively. This work demonstrates that modified BDP-based D-A copolymers with conformational locks has a potential application in the high-performance semiconductor materials.