Highly Crystalline C8-BTBT Thin-Film Transistors by Lateral Homo-Epitaxial Growth on Printed Templates

3 years ago

Highly Crystalline C8-BTBT Thin-Film Transistors by Lateral Homo-Epitaxial Growth on Printed Templates

Paul Heremans, Benjamin Watts, Satya Prakash Bommanaboyena, Robby Janneck, Cedric Rolin, Jan Genoe, Nicolas Pilet

Highly crystalline thin films of organic semiconductors offer great potential for fundamental material studies as well as for realizing high-performance, low-cost flexible electronics. The fabrication of these films directly on inert substrates is typically done by meniscus-guided coating techniques. The resulting layers show morphological defects that hinder charge transport and induce large device-to-device variability. Here, a double-step method for organic semiconductor layers combining a solution-processed templating layer and a lateral homo-epitaxial growth by a thermal evaporation step is reported. The epitaxial regrowth repairs most of the morphological defects inherent to meniscus-guided coatings. The resulting film is highly crystalline and features a mobility increased by a factor of three and a relative spread in device characteristics improved by almost half an order of magnitude. This method is easily adaptable to other coating techniques and offers a route toward the fabrication of high-performance, large-area electronics based on highly crystalline thin films of organic semiconductors. Highly crystalline organic thin films with average carrier mobilities above 10 cm2 V−1 s−1 and parameter spread below 10% are achieved by a double-step method, combining a solution-processed templating layer and a lateral homo-epitaxial growth by a thermal-evaporation step. The epitaxial regrowth repairs most of the morphological defects inherent to meniscus-guided coating techniques. This improves mobility and spread between devices.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/adma.201703864