Air-stable n-channel organic field-effect transistors based on charge-transfer complexes including dimethoxybenzothienobenzothiophene and tetracyanoquinodimethane derivatives

Abstract

A new donor molecule 3,8-dimethoxy-[1]benzothieno[3,2-b][1]benzothiophene (DMeO-BTBT) is synthesized and the charge-transfer complexes with fluorinated 7,7,8,8-tetracyanoquinodimethane (F_n-TCNQ; n = 0, 2, and 4) are prepared. All complexes (DMeO-BTBT)(F_n-TCNQ) have mixed stack structures, and the thin-film and single-crystal organic transistors show n-channel transistor performance both in vacuum and in air even after one-year storage. Although the performance and stability of the thin-film transistors are improved according to the acceptor ability of F_n-TCNQ, all single-crystal transistors exhibit similar performance and excellent air stability, among which the (DMeO-BTBT)(F₂-TCNQ) transistor exhibits the highest mobility of 0.097 cm² V⁻¹ s⁻¹.