The Effects of Side Chains on the Charge Mobilities and Functionalities of Semiconducting Conjugated Polymers beyond Solubilities

• Published in: Advanced materials (Weinheim) Vol. 31; no. 46; pp. e1903104 - n/a
• Main Authors: Yang, Yizhou, Liu, Zitong, Zhang, Guanxin, Zhang, Xisha, Zhang, Deqing
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.11.2019
• Subjects: Chain branching; Chains (polymeric); charge mobility; Crystal structure; Crystallinity; Field effect transistors; field‐effect transistors‐based sensors; Functional groups; Materials science; modifications of side chains; Polymers; Selectivity; semiconducting conjugated polymers; Semiconductor devices; side chains with functional groups; Thin films; Thymine; field-effect transistors-based sensors; side chains with functional groups; semiconducting conjugated polymers; modifications of side chains; charge mobility
• DOI: 10.1002/adma.201903104
• ISSN: 0935-9648

Recent decades have witnessed the rapid development of semiconducting polymers in terms of high charge mobilities and applications in transistors. Significant efforts have been made to develop various conjugated frameworks and linkers. However, studies are increasingly demonstrating that the side chains of semiconducting polymers can significantly affect interchain packing, thin film crystallinity, and thus semiconducting performance. Ways to modify the side alkyl chains to improve the interchain packing order and charge mobilities for conjugated polymers are first discussed. It is shown that modifying the branching chains by moving the branching points away from the backbones can boost the charge mobilities, which can also be improved through partially replacing branching chains with linear ones. Second, the effects of side chains with heteroatoms and functional groups are discussed. The siloxane‐terminated side chains are utilized to enhance the semiconducting properties. The fluorinated alkyl chains are beneficial for improving both charge mobility and air stability. Incorporating H bonding group side chains can improve thin film crystallinities and boost charge mobilities. Notably, incorporating functional groups (e.g., glycol, tetrathiafulvalene, and thymine) into side chains can improve the selectivity of field‐effect transistor (FET)‐based sensors, while photochromic group containing side chains in conjugated polymers result in photoresponsive semiconductors and optically tunable FETs. Recent developments in side chain modifications of conjugated polymers, including alkyl side chains, heteroatom, and functional group containing side chains, are reviewed for field‐effect transistor studies. The review shows that side chain modification can not only improve the charge transport properties, but also endow the conjugated polymers with new functions (malleability, sensing, stimuli‐responsiveness, etc.).