Acceptor-donor-acceptor small molecules based on fuse ring and 2-(2-oxindolin-3-ylidene)malononitrile derivatives for solution-processed n-type organic field-effect transistors

Abstract

The di-cyanovinyl-based small molecules were successfully used as non-fullerene acceptors in high-performance organic solar cells. However, the field-effect performances of these types of small molecules are still rarely studied. In this paper, two acceptor-donor-acceptor (A–D–A) small molecules with fuse ring as donor and strong electron-withdrawing 2-(2-oxindolin-3-ylidene)malononitrile derivatives as acceptors were synthesized and characterized for use in solution-processed organic field-effect transistors (OFETs). The new molecules had deep lowest unoccupied molecular orbital energy level (˜ –4.0 eV) for marching the electron transport and exhibited n-type charge transport characteristics. The OFETs based on the small molecules exhibited the highest electron mobility of over 3 × 10–3 cm2V–1s–1. This work indicates that di-cyanovinyl-based small molecules can also be applied in n-type OFETs.