We report the fabrication of high quality thin films for semiconducting organic donor-acceptor charge-transfer (CT) compounds, (diC8BTBT)(FnTCNQ) (diC8BTBT = 2,7-dioctylbenzothieno[3,2-b]benzothiophene and FnTCNQ [n = 0,2,4] = fluorinated derivatives of 7,7,8,8,-tetracyanoquinodimethane), which have a high degree of layered crystallinity. Single-phase and uniaxially oriented polycrystalline thin films of the compounds were obtained by co-evaporation of the component donor and acceptor molecules. Organic thin-film transistors (OTFTs) fabricated with the compound films exhibited n-type field-effect characteristics, showing a mobility of 6.9 × 10-2 cm2/V s, an on/off ratio of 106, a sub-threshold swing of 0.8 V/dec, and an excellent stability in air. We discuss the suitability of strong intermolecular donor-acceptor interaction and the narrow CT gap nature in compounds for stable n-type OTFT operation.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)