Journal article
High-throughput roll-to-roll X-ray characterization of polymer solar cell active layers
Department of Energy Conversion and Storage, Technical University of Denmark1
Functional organic materials, Department of Energy Conversion and Storage, Technical University of Denmark2
Paul Scherrer Institute3
Imaging and Structural Analysis, Department of Energy Conversion and Storage, Technical University of Denmark4
Synchrotron-based X-rays were used to probe active materials for polymer solar cells on flexible polyester foil. The active material was coated onto a flexible 130 micron thick polyester foil using roll-to-roll differentially pumped slot-die coating and presented variation in composition, thickness, and additives.
The coated foil was passed through a synchrotron X-ray beam on a small unit comprising unwinder and winder for the foil, an X-ray probe station, and a barcode reader for sample registration. Foil lengths of 10 meters were probed and yielded X-ray scattering data for approximately every 1 cm, probing linear variations in processing and coating parameters along the foil.
The demonstration shows that real-time structural characterization of roll-to-roll coating at realistic web-speeds is feasible using synchrotron radiation. Off-line characterization with lower spatial resolution would be possible with dedicated laboratory instruments. We found that poly(3-hexyl)thiophene (P3HT) only crystallizes at a ratio above 1 : 2 with phenyl-C61-butyric acid methyl ester (PCBM) and that an optimum addition of 2 vol% chloronaphthalene (CN) as a processing additive significantly improves polymer crystallinity and crystallite size.
In coated films thinner than 275 nm, textured poly(3-hexyl)thiophene crystallites with the lamellar stack aligned with the substrate dominate, similar to what is observed for spin-coated films.
Language: | English |
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Publisher: | The Royal Society of Chemistry |
Year: | 2012 |
Pages: | 22501-22509 |
ISSN: | 13645501 and 09599428 |
Types: | Journal article |
DOI: | 10.1039/c2jm34596j |
ORCIDs: | Jørgensen, Mikkel , Krebs, Frederik C and Andreasen, Jens Wenzel |