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Title: In situ monitoring of structure formation in the active layer of polymer solar cells during roll-to-roll coating

The active layer crystallization during roll-to-roll coating of organic solar cells is studied in situ. We developed an X-ray setup where the coater unit is an integrated part of the small angle X-ray scattering instrument, making it possible to control the coating process while recording scattering measurements in situ, enabling us to follow the crystal formation during drying. By varying the distance between the coating head and the point where the X-ray beam hits the film, we obtained measurements of 4 different stages of drying. For each of those stages, the scattering from as long a foil as possible is summed together, with the distance from coating head to scattering point kept constant. The results are average crystallographic properties for the active layer coated on a 30 m long foil. With this insight into the dynamics of crystallization in a roll-coated polymer film, we find that the formation of textured and untextured crystallites seems uncorrelated, and happens at widely different rates. Untextured P3HT crystallites form later in the drying process than expected which may explain previous studies speculating that untextured crystallization depends on concentration. Textured crystallites, however, begin forming much earlier and steadily increases as the film dries, showing amore » development similar to other in situ studies of these materials.« less
Authors:
; ; ; ;  [1]
  1. Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 (Denmark)
Publication Date:
OSTI Identifier:
22299792
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 8; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CONTROL; CRYSTALLIZATION; CRYSTALLOGRAPHY; CRYSTALS; FILMS; MONITORING; ORGANIC SOLAR CELLS; POLYMERS; SMALL ANGLE SCATTERING; SURFACE COATING; X RADIATION; X-RAY DIFFRACTION