Perfluoroalkyl-functionalized thiazole-thiophene oligomers as N-channel semiconductors in organic field-effect and light-emitting transistors

Hakan Usta*, William Christopher Sheets, Mitchell Denti, Gianluca Generali, Raffaella Capelli, Shaofeng Lu, Xinge Yu, Michele Muccini, Antonio Facchetti

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

73 Scopus citations

Abstract

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 π-deficient building blocks. Since thiazole insertion into π-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-thiophene 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 (μe) as high as 1.30 cm2/(V·s) (Ion/Ioff > 106) for films of 2 deposited at room temperature. In contrary to previous studies, we show here that 2,2′-bithiazole can be a very practical building block for high-performance n-channel semiconductors. Additionally, upon 2,2′- and 5,5′-bithiazole insertion into a sexithiophene backbone of well-known DFH-6T, significant charge transport improvements (from 0.001-0.021 cm2/(V·s) to 0.20-0.70 cm2/(V·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 π-conjugated semiconductor thin-films, and it should be studied more in future optoelectronic applications.

Original languageEnglish (US)
Pages (from-to)6542-6556
Number of pages15
JournalChemistry of Materials
Volume26
Issue number22
DOIs
StatePublished - Nov 25 2014

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Materials Chemistry

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