A disordered layered phase in thin films of sexithiophene

• Published in: Chemical physics letters 2013-06, Vol.574, p.51-55
• Main Authors: Moser, Armin, Salzmann, Ingo, Oehzelt, Martin, Neuhold, Alfred, Flesch, Heinz-Georg, Ivanco, Jan, Pop, Sergiu, Toader, Teodor, Zahn, Dietrich R.T., Smilgies, Detlef-Matthias, Resel, Roland
• Format: Article
• Language: English
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2013.04.053

[Display omitted] •X-ray diffraction techniques for an in-depth characterization of vacuum evaporated thin films of sexithophene.•Growth rate leads to a co-existence of several crystallographic phases and molecular orientations.•High growth rates induce a kinetically stabilized disordered layered phase in sexithiophene thin films.•Low deposition rates are benefical for high crystalline quality of sexithiophene functional layers. This Letter reports the impact of the evaporation rate on the crystallographic phase formation of vacuum deposited α-sexithiophene thin films studied by X-ray diffraction methods. The experiments reveal the formation of two crystal phases, one of which is a thermodynamically stable phase occurring at low rates, while the second is favored by high rates. This second phase exhibits an increased layer spacing and diffraction features typical for two-dimensional crystals which are laterally ordered but without interlayer correlations of the molecular positions. This disordered layered phase comprises molecules of nonuniform conformations, and is kinetically induced.