Synthesis, properties, and FET performance of rectangular oligothiophene

Abstract

New rectangular oligothiophene bearing benzothiophene units at the corner positions has been successfully synthesized via the Eglinton-Galbraith coupling reaction. This oligomer dissolves in common organic solvents, which makes it a candidate for solution-processable semiconductor materials. The electronic absorption and electrochemical properties of the cyclic oligomer were compared with those of the corresponding linear components. The properties of their oxidized species were also compared. Organic field-effect transistors fabricated from its spin-coating film showed typical p-type characteristics and achieved good hole mobility up to 7.3 × 10⁻³ cm²V⁻¹ s⁻¹ with an on/off current ratio of 2.0 × 10⁸ and a threshold voltage of −7 V.