Influence of Solvent on the Film Morphology, Crystallinity and Electrical Characteristics of Triisopropylsilyl Pentacene OTFTs.

The thin-film morphology, degree of crystallinity, as well as the electrical properties of triisopropylsilyl (TIPS) pentacene organic thin-film transistors (OTFTs) were significantly influenced by the solvent used for spin-coating a TIPS pentacene layer. The TIPS pentacene films spin-coated from solvents having high boiling points (chlorobenzene and xylene) showed dendritelike morphology and a higher degree of crystallinity, while TIPS pentacene spin-coated from solvent having a low boiling point (chloroform) showed amorphous-like morphology and a lower degree of crystallinity. The field-effect mobility of OTFTs fabricated from chlorobenzene was 4 X 10^-2 cm²/V s, whereas mobility of 10^-4 to 10^-5 cm²/V s was achieved when using chloroform. This implies that the morphology, crystallinity, as well as the electrical properties of TIPS pentacene have a strong dependence on the solvent used for spin-coating. [ABSTRACT FROM AUTHOR]