Four derivatives of dithieno[2,3-d;2′,3′-d′]benzo[1,2-b;3,4-b′]dithiophene (DTmBDT) have been synthesized to investigate the correlation between molecular structure, thin-film organization, and charge-carrier transport. Phenyl or thiophene end-capped derivatives at alpha positions of the outer thiophenes of DTmBDT present vastly different optoelectronic properties in comparison with bay-position alkyl-chain-substituted DTmBDT, which was additionally confirmed by density functional theory simulations. The film morphology of the derivatives strongly depends on alkyl substituents, aromatic end-caps, and substrate temperature. Field-effect transistors based on DTmBDT derivatives with bay-substituted alkyl chains show the best performance within this studied series with a hole mobility up to 0.75 cm²/V s. Attachment of aromatic end-caps disturbs the ordering, limiting the charge-carrier transport. Higher substrate temperature during deposition of the DTmBDT derivatives with aromatic end-caps results in larger domains and improved the transistor mobilities but not beyond the alkylated DTmBDT.

中文翻译：

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场效应晶体管的二噻吩并[2,3- d ; 2'，3'- d ]苯并[2,1- b：3,4- b ']二噻吩的分子排序

合成了四噻吩并[2,3- d ; 2'，3'- d ']苯并[1,2- b ; 3,4- b ']二噻吩（DT m BDT）的四种衍生物以研究分子之间的相关性结构，薄膜组织和电荷载流子传输。与海湾位置烷基链取代的DT m BDT相比，DT m BDT的外部噻吩的α位上的苯基或噻吩封端的衍生物表现出极大的光电特性，此外还通过密度泛函理论仿真得到了证实。衍生物的膜形态在很大程度上取决于烷基取代基，芳族封端和底物温度。基于具有海湾取代烷基链的DT m BDT衍生物的场效应晶体管在该研究系列中显示出最佳性能，其空穴迁移率高达0.75 cm ² / V s。芳族封端的连接会扰乱有序排列，从而限制了载流子的传输。DT m BDT衍生物与芳族封端的沉积过程中较高的基板温度会导致更大的畴并改善晶体管迁移率，但不会超出烷基化的DT m BDT。