Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 2: Focus Session: Structural Ordering and Electronic Transport I (jointly with CPP)
HL 2.3: Talk
Monday, March 26, 2012, 10:15–10:30, ER 270
Determination of the Crystallinity of Semicrystalline Poly(3-hexyl thiophene) by Means of Wide Angle X-Ray Scattering — •Jens Balko1, Ruth Lohwasser2, Michael Sommer3, Mukundan Thelakkat2, and Thomas Thurn-Albrecht1 — 1Institute of Physics, Martin-Luther-University Halle-Wittenberg, 06120 Halle — 2Applied Functional Materials, Macromolecular Chemistry I, University of Bayreuth, 95440 Bayreuth — 3Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Cambridge
Poly(3-hexyl thiophene) (P3HT) is a common polymer semiconductor, often used as material or component in organic field effect transistors or solar cells. The crystallinity of this semicrystalline material is among other parameters governing the electronic mobility. However, at present there is no routine method available to determine an absolute value for the crystallinity, and the values given in the literature e.g. for the enthalpy of melting vary by a factor of three. Wide Angle X-Ray Scattering (WAXS) probes the crystals as well the amorphous parts of the sample and there exists an established procedure to measure the crystallinity (RULAND, 1961) based on scattering data. The result is used for a reliable calibration of the melting enthalpy that can serve as a reference value for more convenient calorimetric techniques. We compare the crystallinity for a number of chemically well-defined samples, with different molecular weight and a typical commercial sample with broad molecular weight distribution. In addition, for some selected samples we study the influence of temperature on crystallinity.