While the development of high-performing n-type polymer semiconductors remains a challenge, the involving of costly transition-metal catalysts and even toxic reagents during the preparation of these materials might also cause serious environmental issues. Herein, by devising two new aldehyde-functionalized bithiophene imide (BTI)-type building blocks, we designed and synthesized two acceptor-acceptor type n-type polymers, BTI-BD and BTI2-BD, on the basis of an environmentally benign, transition metal-free and thus cost-effective aldol condensation. The resulting polymers exhibited planar and rigid backbone conformations and low-lying LUMO energy levels close to −4.0 eV, thus leading to unipolar n-type tranport character with a highest electron mobility of 1.35 × 10−3 cm2 V−1 s−1 in organic field-effect transistors for the BTI2-BD polymer which features a higher molecular ordering in solid state. Our results demonstrate that the aldol polycondensation strategy could serve as a cheaper and more ecofriendly alternative to the convential transition metal-catalyzed cross-coupling reactions for constructing n-type acceptor-acceptor polymers with unipolar n-type charge transport characteristics.
Bibliographical noteFunding Information:
D. Wang and Y. Hou contributed equally to this work. The authors acknowledge the financial support by the National Natural Science Foundation of China ( 22005133 and 52173171 ). K.Y. is grateful to the Guangdong Basic and Applied Basic Research Foundation ( 2022A1515010935 ). X.D. thanks for the financial support from the National Natural Science Foundation of China (Grant No. 52273171 and 21875055 ) and the Shenzhen Research Foundation Project (Grant GXWD20201230155427003 ). The authors are also grateful for the technical support from SUSTech Core Research Facilities and the Computational Science and Engineering of Southern University of Science and Technology.
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ASJC Scopus subject areas
- General Chemical Engineering
- Process Chemistry and Technology