Modification of Indacenodithiophene-Based Polymers and Its Impact on Charge Carrier Mobility in Organic Thin-Film Transistors

• Published in: Journal of the American Chemical Society 2020-01, Vol.142 (2), p.652-664
• Main Authors: Wadsworth, Andrew, Chen, Hu, Thorley, Karl J, Cendra, Camila, Nikolka, Mark, Bristow, Helen, Moser, Maximilian, Salleo, Alberto, Anthopoulos, Thomas D, Sirringhaus, Henning, McCulloch, Iain
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.9b09374

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.