Correlation of molecular structure, packing motif and thin-film transistor characteristics of solution-processed n-type organic semiconductors based on dodecyl-substituted C60 derivatives

We report the performance of solution-processed n-type organic thin-film transistors (OTFTs) based on four different types of dodecyl-substituted C60 derivatives. Crystallinity and morphology of the spin-coated films highly depend on the compounds. C60-fused N-methylpyrrolidine-meta-C12 phenyl (C60MC12) exhibited the highest crystallinity and mobility of 0.09 cm2/Vs among the compounds investigated. We found that not only chain-length but also chain-orientation play an important role for fabrication of highly ordered crystalline film, leading to high electron mobility in solution-processed n-type OTFTs.