Transient phases during fast crystallization of organic thin films from solution

We report an in situ microbeam grazing incidence X-ray scattering study of 2,7-dioctyl[1] benzothieno[3,2-b][1] benzothiophene (C-8-BTBT) organic semiconductor thin film deposition by hollow pen writing. Multiple transient phases are observed during the crystallization for substrate temperatures up to approximate to 93 degrees C. The layered smectic liquid-crystalline phase of C-8-BTBT initially forms and preceedes interlayer ordering, followed by a transient crystalline phase for temperature > 60 degrees C, and ultimately the stable phase. Based on these results, we demonstrate a method to produce extremely large grain size and high carrier mobility during highspeed processing. For high writing speed (25 mm/s), mobility up to 3.0 cm(2)/V-s has been observed. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.