We report an in-situ microbeam grazing incidence X-ray scattering study of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) organic semiconductor thin film deposition by hollow pen writing. Multiple transient phases are observed during the crystallization for substrate temperatures up to ≈93∘C. The layered smectic liquid-crystalline phase of C8-BTBT initially forms and preceedes inter-layer ordering, followed by a transient crystalline phase for temperature >60∘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 high-speed processing. For high writing speed (25 mm/s) mobility up to 3.0 cm2/V-s has been observed.
@article{arxiv.1509.09250,
title = {Transient phases during fast crystallization of organic thin films from solution},
author = {Jing Wan and Yang Li and Jeffrey G. Ulbrandt and Detlef-M. Smilgies and Jonathan Hollin and Adam C. Whalley and Randall L. Headrick},
journal= {arXiv preprint arXiv:1509.09250},
year = {2015}
}