Issue 19, 2019

Fluorination and chlorination effects on quinoxalineimides as an electron-deficient building block for n-channel organic semiconductors

Abstract

The quinoxalineimide (QI) unit, containing the electron-withdrawing quinoxaline and imide groups, is an electron-deficient building block for organic semiconductor materials. In this study, three fluorinated or chlorinated QIs (QI-1F, QI-2F, and QI-2Cl), have been designed and developed. We report the impact of the fluorination or chlorination of the QI unit on the electronic structures and charge carrier transport properties as compared to unsubstituted QI (QI-2H) bearing the same n-hexyl side chains. The frontier molecular orbital energy levels downshifted with the incorporation of fluorine or chlorine atoms onto the π-framework of QI. Single-crystal structure analyses revealed that all QI-based molecules have an entirely planar backbone and are packed into two-dimensional slipped stacks with diagonal electronic coupling that enables two-dimensional charge carrier transport. Notably, the doubly fluorinated or chlorinated QIs formed compact molecular packing in the single-crystal structures through an infinite intermolecular network relative to unsubstituted QI (QI-2H). The field-effect transistor-based QI molecules exhibited typical n-channel transport properties. As compared to unsubstituted QI (QI-2H), the chlorinated QI exhibited improved electron mobilities up to 7.1 × 10−3 cm2 V−1 s−1. The threshold voltages of the fluorinated or chlorinated QI devices were clearly smaller than that of QI-2H, which reflects the lowest unoccupied molecular orbital levels of the molecules. This study demonstrates that the fluorinated or chlorinated QIs are versatile building blocks in creating n-channel organic semiconductor materials.

Graphical abstract: Fluorination and chlorination effects on quinoxalineimides as an electron-deficient building block for n-channel organic semiconductors

Supplementary files

Article information

Article type
Paper
Submitted
31 mar. 2019
Accepted
01 apr. 2019
First published
08 apr. 2019
This article is Open Access
Creative Commons BY license

RSC Adv., 2019,9, 10807-10813

Fluorination and chlorination effects on quinoxalineimides as an electron-deficient building block for n-channel organic semiconductors

T. Hasegawa, M. Ashizawa, S. Kawauchi, H. Masunaga, N. Ohta and H. Matsumoto, RSC Adv., 2019, 9, 10807 DOI: 10.1039/C9RA02413A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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