In this work, bis-(triisopropylsilylethynyl) pentacene (TIPS pentacene) films were fabricated with a newly designed system for controlled solution casting with adjustable nitrogen flow and deposition temperature, which consequently enabled a systematic examination of crystal orientation-dependent mobilities in single crystal and single-crystal textured TIPS pentacene transistors. One of the two π-π stacking directions in TIPS pentacene films was found to be close to [2 1 0] (or the long axis of needle-shaped TIPS pentacene films), with frequent twinning observed between crystalline domains across the (1 over(2, -) 0) planes that are the lateral facets for individual crystallites. The [2 1 0] axes of crystalline TIPS pentacene thin films ran across source-drain channels at different angles, showing a ten-fold hole mobility increase as the [2 1 0] crystallographic axis became parallel to the channel direction. Our results also suggest that the controlled solution casting may be a promising method in fabricating solution-processible small-molecule organic semiconductors with varied morphologies.
|Number of pages||8|
|State||Published - Jul 2009|
Bibliographical noteFunding Information:
The authors thank the Office of Naval Research and the National Science Foundation for financial supports (DMR-0084304 and DMR-6518079). TEM studies and electrical characterizations were conducted in the Electron Microbeam Analysis Laboratory and Solid State Electronics Laboratory at the University of Michigan at Ann Arbor.
- Charge-transport anisotropy
- Controlled solution process
- Functionalized pentacene
- Twin boundary
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Chemistry (all)
- Condensed Matter Physics
- Materials Chemistry
- Electrical and Electronic Engineering