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Published on: October 24, 2017
Synthesis and n-Type Semiconducting Properties of Bis(dioxaborin) Compounds Containing a π-Extended 2,2'-Bithiophene
Yohei Kojima1, So Sugiura1, Keiji Suzuki1
1Graduate School of Engineering, Nagoya Institute of Technology Gokiso, Showa-ku, Nagoya, 466-8555, Japan.
Abstract:
Bis(dioxaborin) compounds containing π-conjugated systems have been studied as n-type semiconductors for organic field-effect transistors (OFETs). In this study, with the aim of investigating the effect of the extension of the π-conjugation on the n-type semiconducting properties and stability of bis(dioxaborin) compounds, we synthesized new compounds containing 2,2'-bithiophene derivatives extended with an olefin or an acetylene spacer. The absorption maxima of the compounds containing olefin spacers were greatly red-shifted compared with those of the original compound without a π-spacer. The newly synthesized compounds exhibited high electron affinity, and the olefin spacers effectively reduced the on-site Coulomb repulsion in the two-electron reduction of the compounds. An OFET fabricated using one of these compounds having a layer-by-layer crystal structure exhibited n-type semiconductor behavior with a low threshold voltage, most likely due to the small on-site Coulomb repulsion. The electron-transporting properties were investigated by theoretical calculations based on the Marcus theory.
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