The effect of air exposure on the crystal structure of oligo-thiophene thin films investigated using in situ X-ray diffraction

Takeshi Watanabe (1) , Tomoyuki Koganezawa , Mamoru Kikuchi , Christine Videlot-Ackermann (2) , Jörg Ackermann (2) , Hugues Brisset (3) , Noriyuki Yoshimoto , Ichiro Hirosawa

1 Kyoto University
2 CINaM - Centre Interdisciplinaire de Nanoscience de Marseille
3 MAPIEM - Laboratoire Matériaux Polymères Interfaces Environnement Marin - EA 4323

The effect of air exposure on the crystal structure of alkyl substituted organic thin film was studied using in situ grazing incidence X-ray diffraction (GIXD) measurements. The GIXD measurements were carried out by scanning the specific qxy region using a two-dimensional area detector and the Soller slit. The a and b axes of the monoclinic unit cell were found to shrink by air exposure. As for the c axis, there was no detectable change caused by air exposure. The shrinking of the a and b axes immediately occurred after exposure to air, and then saturated in six days. The shrinking of the a and b axes by air exposure might affect the transport properties, because shortening between intermolecular distances should promote the hopping of hole carriers.

Mots clés: A1. X-ray diffractionB2. Semiconducting materialsA2. Polycrystalline depositionB3. Field effect transistorsA3. Physical vapor deposition processesB1. Organic compounds

Domaines: Chimie; Cristallographie

Takeshi Watanabe, Tomoyuki Koganezawa, Mamoru Kikuchi, Christine Videlot-Ackermann, Jörg Ackermann, et al.. The effect of air exposure on the crystal structure of oligo-thiophene thin films investigated using in situ X-ray diffraction. Journal of Crystal Growth, 2017, 468, pp.816-820. ⟨10.1016/j.jcrysgro.2017.01.051⟩. ⟨hal-02533219⟩