Document Type

Journal Article

Title

Organic soluble indigoids derived from 3-hydroxybenzaldehyde for N-type organic field-effect transistor (OFET) applications

Department/Unit

Department of Physics

Language

English

Abstract

Two new series of organic soluble indigoids 7-7′-dialkoxyindigoids (2a, 2b) and 4,4′-dibromo-7,7′-dialkoxyindigoids (3a, 3b) (alkoxy = n-butoxy and n-octyloxy) were synthesized starting from the inexpensive 3-hydroxybenzaldehyde. The indigoids were soluble in common organic solvents including chloroform, dichloromethane, toluene, ethyl acetate and ethers. The enhanced solubility was suggested to be a lack of intermolecular hydrogen-bonds as confirmed by single crystal X-ray diffraction analyses. It was found that intramolecular hydrogen-bonds in indigoids are crucial to the exhibition of field-effect in OFETs, while intermolecular hydrogen-bonds only caused insolubility of the indigoids. Compared to the pristine insoluble indigo (LUMO = −3.55 eV and Eg = 1.91 eV), the soluble indigoids containing electron donating alkoxy side chains at the indigoid 7 and 7′ positions were shown to have their LUMO decreased by −0.13 to −0.26 eV. Among the indigoid studied, the soluble indigoid 3a containing electron donating alkoxy side chains at the indigoid 7 and 7′ positions and bromine groups at the indigoid 4 and 4′ positions exihibited a narrowest bandgap energy with Eg = 1.66 eV. Employing the same fabrication technique and a bottom-gate-top-contact OFET configuration, the soluble indigoids were found to have electron mobility similar to and within an order of magnitude of the pristine indigo.

Keywords

OFET, Baeyer Drewson indigo synthesis, 3-Hydroxybenzaldehyde, Organic semiconductors, Organic soluble indigoids

Publication Date

5-31-2016

Source Publication Title

Organic Electronics

Volume

32

Start Page

258

End Page

266

Publisher

Elsevier

Peer Reviewed

1

DOI

10.1016/j.orgel.2016.02.035

Link to Publisher's Edition

http://dx.doi.org/10.1016/j.orgel.2016.02.035

ISSN (print)

15661199

ISSN (electronic)

18785530

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