Solution-processed n-type organic thin-film transistors with high field-effect mobility

We report the performance of solution-processed $n$ -type organic thin-film transistors (OTFTs) based on ${\mathrm{C}}_{60}$ derivatives. Long-chain alkyl-substituted ${\mathrm{C}}_{60}$ , C60-fused $N$ -methylpyrrolidine-meta-C12 phenyl (C60MC12), was used as a semiconducting layer. The C60MC12-thin-film transistor shows high electron mobility of $0.067{\mathrm{cm}}^2∕\mathrm{V}\mathrm{s}$ in saturation regime. From the result of x-ray diffraction analysis, the C60MC12 active layer forms highly ordered crystalline film. We found that self-assemble ability of long alkyl chains plays an important role for fabrication of highly ordered crystalline film, leading to achievement of high electron mobility in solution-processed $n$ -type OTFTs.