An A−D−Aʹ−Dʹ strategy enables perylenediimide-based polymer dyes exhibiting enhanced electron transport characteristics

Abstract

In this work, we develop two new A−D−Aʹ−Dʹ type polymer dyes, namely PPDIDTBT and PPDIDTBT-2F, containing perylenediimide (PDI), thiophene, and benzothiadiazole units. Both polymer dyes have high thermal stability and broad absorption throughout the UV–vis region. More importantly, the introduction of the second electron-withdrawing units, benzothiadiazoles, endows both polymer dyes with low-lying LUMO energy levels of −3.85 eV for PPDIDTBT and −3.88 eV for PPDIDTBT-2F. The charge transport properties of the two polymer dyes were examined by fabricating organic field-effect transistors (OFETs) with top-gate/bottom-contact configuration. Both polymer dyes exhibit enhanced electron transport characteristics with the highest electron mobility of 0.070 cm2 V−1 s−1, which is among the highest values for PDI-based polymer semiconductors reported to date. Our results highlight that the A−D−Aʹ−Dʹ strategy is a useful approach in tuning orbital energetic and charge transport properties of polymer dyes for developing high-performance OFETs.