Tailoring the crystallinity of solution-processed 6,13-bis(triisopropylsilylethynyl)pentacene via controlled solidification

Abstract

Solution processing is one of the most important techniques for producing large-area, uniform films for printed electronics via a low-cost process. Herein, we propose a time-controlled spin-coating method to improve the crystallinity of films of the solution-processable organic small-molecule semiconductor 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene). A key factor in this process was to halt spinning before drying had begun. We used microscopic and spectroscopic analyses to systematically investigate the effect of spinning time on the evaporation rate of solvent at different spinning rates. We found that the crystallinity of the TIPS-pentacene thin films was substantially enhanced when the spinning time was limited to a few seconds, without post-treatment. We fabricated field-effect transistors using thin films deposited by this method and found that the field-effect mobility was enhanced ∼100-fold compared with that of a device fabricated using a film deposited by the conventional spin-coating method.