High-Mobility Organic Single-Crystal Microtubes of Soluble Pentacene Semiconductors with Hollow Tetragonal Structures

We report a facile but very effective solution phase method for the self-assembly of one-dimensional (1D) single-crystal organic microtubes with hollow tetragonal structures using triisopropylsilylethynyl pentacene (TIPS_PEN). We found that the self-assembled TIPS_PEN microtubes are formed by self-etching of microsolid by residual toluene solvent. The self-etching commences at the ends of the solid rectangular microribbons and then continues toward the interiors along their length axes. The resultant microtubes showed completely well-defined single-crystalline nature. The transistor devices based on individual microtube yielded a high field-effect mobility of 1.73 cm 2 /V s and an on/off ratio of ∼10 6, which are among the best values reported up to date for solution-processed micro-TFTs with organic single crystals. We believe that these well-defined microtubular structures of an organic semiconductor will be useful in the fields of p/n heterojunction photovoltaics, optical waveguides, and biological research.