Dense Assembly of Soluble Acene Crystal Ribbons and Its Application to Organic Transistors

The preparation of uniform large-area highly crystalline organic semiconductor single crystals remains a challenge in the field of organic field-effect transistors (OFETs). Crystal densities in the channel regions of OFETs have not yet reached sufficiently high values to provide efficient charge transport, and improving channel crystal densities remains an important research area. Herein we fabricated densely well-aligned single crystal arrays of the 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS_PEN) semiconductor using a straightforward scooping-up (SU) methodology to quickly produce a large-area self-assembled semiconductor crystal layer. The resulting crystalline TIPS_PEN strip arrays obtained using the SU method revealed a packing density that was 2.76 times the value obtained from the dip-coated channel, and the mean interspatial distance between the crystal strips decreased from 21.5 to 7.8 μm. The higher crystal packing density provided efficient charge transport in the FET devices and directly yielded field-effect mobilities as high as 2.16 cm(2)/(V s). These field-effect mobilities were more than three times the values obtained from the OFETs prepared using dip-coated channels. Furthermore, the contact resistance between the source/drain electrodes and the TIPS_PEN crystals decreased by a factor of 2. These contributions represent a significant step forward in improving semiconductor crystal alignment for the fabrication of large-area high-performance organic electronics.