The polymer indacenodithiophene-co-benzothiadiazole (IDT-BT) has been thoroughly studied for its use in p-type organic thin-film transistors over the course of the past decade. While a variety of modifications have been made to its structure, few analogues have been able to match or surpass the hole mobility that can be obtained by IDT-BT. Here, we discuss the rationale behind the chemical modifications that have been utilized and suggest design principles toward high-mobility indacenodithiophene-based polymers. It is clear that planarizing intramolecular interactions, which exist between the peripheral thiophene of the IDT unit and the benzothiadiazole, are imperative for achieving high hole mobilities in this relatively amorphous polymer. Moreover, despite the less ordered backbones of the extended fused-ring cores that have recently been utilized (TIF-BT and TBIDT-BT), high mobilities were still attained in these polymers owing to additional interchain charge transfer. Thus, maintaining the beneficial thiophene-benzothiadiazole intramolecular interactions, while further extending the IDT core to promote interchain charge transfer, is a logical strategy toward high-mobility p-type polymers.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors thank KAUST for financial support and acknowledge EC FP7 Project SC2 (610115), EC H2020 (643791), and EPSRC Projects EP/G037515/1, EP/ M005143/1, and EP/L016702/1. A.S. and C.C. gratefully acknowledge financial support from the National Science
Foundation, Division of Materials Research Award No. 1808401. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02- 76SF00515. The authors would also like to thank Aditya Sadhanala for providing the PDS data on IDTT-BT.