Perfluoroalkyl-Functionalized Thiazole鈥揟hiophene Oligomers as N-Channel Semiconductors in Organic Field-Effect and Light-Emitting Transistors

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• 作者：Hakan Usta ; William Christopher Sheets ; Mitchell Denti ; Gianluca Generali ; Raffaella Capelli ; Shaofeng Lu ; Xinge Yu ; Michele Muccini ; Antonio Facchetti
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：November 25, 2014
• 年：2014
• 卷：26
• 期：22
• 页码：6542-6556
• 全文大小：776K
• ISSN：1520-5002

文摘

Despite their favorable electronic and structural properties, the synthetic development and incorporation of thiazole-based building blocks into n-type semiconductors has lagged behind that of other 蟺-deficient building blocks. Since thiazole insertion into 蟺-conjugated systems is synthetically more demanding, continuous research efforts are essential to underscore their properties in electron-transporting devices. Here, we report the design, synthesis, and characterization of a new series of thiazole鈥搕hiophene tetra- (1 and 2) and hexa-heteroaryl (3 and 4) co-oligomers, varied by core extension and regiochemistry, which are end-functionalized with electron-withdrawing perfluorohexyl substituents. These new semiconductors are found to exhibit excellent n-channel OFET transport with electron mobilities (渭_e) as high as 1.30 cm²/(V路s) (I_on/I_off > 10⁶) for films of 2 deposited at room temperature. In contrary to previous studies, we show here that 2,2鈥?bithiazole can be a very practical building block for high-performance n-channel semiconductors. Additionally, upon 2,2鈥? and 5,5鈥?bithiazole insertion into a sexithiophene backbone of well-known DFH-6T, significant charge transport improvements (from 0.001鈥?.021 cm²/(V路s) to 0.20鈥?.70 cm²/(V路s)) were observed for 3 and 4. Analysis of the thin-film morphological and microstructural characteristics, in combination with the physicochemical properties, explains the observed high mobilities for the present semiconductors. Finally, we demonstrate for the first time implementation of a thiazole semiconductor (2) into a trilayer light-emitting transistor (OLET) enabling green light emission. Our results show that thiazole is a promising building block for efficient electron transport in 蟺-conjugated semiconductor thin-films, and it should be studied more in future optoelectronic applications.