Wang, Tao, Dunbar, Alan D. F., Staniec, Paul A., Pearson, Andrew J., Hopkinson, Paul E., Macdonald, John Emyr ![]() |
Abstract
The power conversion efficiency in a conjugated polymer-functionalized fullerene bulk heterojunction organic photovoltaic (OPV) device is dependent both on the electronic properties of the constituent materials and on the nanoscale morphology of the active semiconductor layer thin-film. Here we use in situ ellipsometry and grazing incidence X-ray scattering (GI-XS) to study molecular self-organization in poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) blend films in real time, during the drying process as they are cast from solution. We illustrate the evolution of the extinction coefficient from a solution to a solid, semi-crystalline state. We show that once the solvent fraction in the film falls below 50%, the P3HT undergoes rapid crystallization via heterogeneous nucleation; a process that is complete in seconds. We also evidence a rapid, dynamic self-annealing process that reduces the characteristic lamella spacing in the P3HT crystallites. The mechanistic understanding of film-formation demonstrated here is an important component in optimizing deposition processes suitable for large-area OPV manufacture.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Physics and Astronomy |
Subjects: | Q Science > QC Physics |
Publisher: | RSC |
ISSN: | 1744-683X |
Last Modified: | 19 Oct 2022 09:05 |
URI: | https://orca.cardiff.ac.uk/id/eprint/19973 |
Citation Data
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