Solution-grown aligned crystals of diketopyrrolopyrroles (DPP)-based small molecules: Rough surfaces and relatively low charge mobility

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• 作者：Zhuo-Ting Huang ; Cong-Cheng Fan ; Guo-Biao Xue ; Jia-Ke Wu ; Shuang Liu ; Huan-Bin Li ; Hong-Zheng Chen ; Han-Ying Li ; ^{hanying_li@zju.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Diketopyrrolopyrrole ; Crystals ; Solution processing ; Organic field-effect transistors ; Morphology
• 刊名：Chinese Chemical Letters
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：27
• 期：4
• 页码：523-526
• 全文大小：1077 K

文摘

Field-effect transistors (FETs) of three diketopyrrolopyrroles (DPP)-based small molecules, 3,6-bis(5-phenylthiophene-2-yl)-2,5-bis(2-ethylhexyl)pyrrolo[3,4-c]pyrrole-1,4-dione (PDPPP), 3,6-bis(5-(4-fluorophenyl)thiophene-2-yl)-2,5-bis(2-ethylhexyl)pyrrolo[3,4-c]pyrrole-1,4-dione (FPDPPPF) and 3,6-bis(5-(4-n-butylphenyl)thiophene-2-yl)-2,5-bis(2-ethylhexyl)pyrrolo[3,4-c]pyrrole-1,4-dione (BuPDPPPBu), have been studied in this work. Well aligned crystals of the three molecules were grown from para-xylene by droplet-pinned crystallization method. FETs based on these aligned crystals exhibit a hole mobility up to 0.19 cm² V⁻¹ s⁻¹ and electron mobility up to 0.008 cm² V⁻¹ s⁻¹. The achieved hole mobility is of the same order of magnitude as reported highest hole mobility for DPP-based small molecules, but it is much lower than that of the high-performance DPP-based polymers. The relative low mobility is mainly attributed to the rough crystal surfaces with steps and, thus, non-smooth charge transport channels at the interfaces between the crystals and the dielectrics. This work has implications for understanding the low charge mobility of DPP-based small molecules.