Diketopyrrolopyrrole based small molecular semiconductors containing thiazole units for solution-processed n-channel thin-film transistors. (April 2019)

• Record Type: Journal Article
• Authors: Tang, Meizhu; Wu, Sicheng; Xing, Weilong; Shen, Hongguang; Xiang, Lanyi; Liang, Yingying; Xu, Wei; Zhu, Daoben
• Is Part Of: Dyes and pigments. Volume 163(2019)
• Page Start: 707
• Page End: 714
• Publication Date: 2019-04
• Subjects: Thiazole unit -- Small molecules -- Diketopyrrolopyrrole -- Solution-processed n-channel thin-film transistors -- Air stability; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2018.12.059
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: In this work, three diketopyrrolopyrrole-based conjugated small molecular semiconductors characterized by the combination of a diketopyrrolopyrrole (DPP) central core, thiazole π-conjugated moiety, and dicyanovinyl end group with different alkyl side chain substituents, 2TzDPPA1-2DCV, 2TzDPPA2-2DCV, and 2TzDPPA3-2DCV were synthesized. These small molecules have a similar narrow band gap of about 1.50 eV and deep LUMO energy level at −4.30 eV. Under ambient conditions, electron mobilities of 0.28 cm 2 V −1 s −1, 0.13 cm 2 V −1 s −1, 0.25 cm 2 V −1 s −1 for solution processed thin films of 2TzDPPA1-2DCV, 2TzDPPA2-2DCV, and 2TzDPPA3-2DCV were obtained, due to high crystallinity and well-organized molecular stacking. Compared with the other two materials, thin films of 2TzDPPA1-2DCV enable the best OFET performance with desirable I on /I off rates exceeding of 10 7, attribute to the coefficient of smoother film morphology and stronger crystallinity. These results reveal that introducing the thiazole unit into the DPP-based conjugated skeleton is conducive to enhance the crystallinity and tailor LUMO energy levels which ensure good performance and excellent stability of these molecules as active materials for n-channel electronic devices. Highlights: Three DPP-based conjugated small molecules, 2TzDPPA1-2DCV, 2TzDPPA2-2DCV, and 2TzDPPA3-2DCV were synthesized. All compounds have a similar narrow band gap of about 1.50 eV, deep LUMO energy level at −4.30 eV and high crystallinity. The highest electron mobility up to 0.28 cm 2 V −1 s −1 was obtained via spin-coating under ambient conditions.