1. Enhancement in crystallinity of poly(3-hexylthiophene) thin films prepared by low-temperature drop casting.
- Author
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Salammal Shabi, Thankaraj, Grigorian, Souren, Brinkmann, Martin, Pietsch, Ullrich, Koenen, Nils, Kayunkid, Navaphun, and Scherf, Ullrich
- Subjects
POLYMERS ,THIN films ,ELECTRONIC industries ,TRANSMISSION electron microscopy ,X-ray diffraction ,THERMODYNAMICS - Abstract
Low-temperature casting of high molecular weight (HMW > 40 kDa) regioregular poly(3-hexylthiophene) (P3HT) is demonstrated to yield highly crystalline P3HT thin films with well defined and preferentially edge-on oriented [(100) contact plane] nanocrystallites on the pure and silanized Si/SiO
2 substrates. Transmission electron microscopy and X-ray diffraction provide evidence for the increase in preferential edge-on orientation of P3HT-conjugated backbone while decreasing the film preparation temperature below room temperature. The optimum growth temperature is about −12°C for the given concentration (2 mg/mL in CHCl3 ). The reduced evaporation rate of the solvent results in a better selection of the thermodynamically stable orientation of nanocrystallites onto the substrate. The degree of preferential orientation and size of the crystallites can be further increased on n-octadecyltrichlorosilane-treated SiO2 substrates as well as by annealing the films at 200°C for 1 h. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]- Published
- 2012
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