Berlin 2015 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 30: P2: Organic Electronics and Photovoltaics
CPP 30.16: Poster
Tuesday, March 17, 2015, 14:00–16:00, Poster B
Morphology of PCPDTBT:PC71BM Thin Films for Organic Photovoltaics — •Christoph J. Schaffer1, Johannes Schlipf1, Bo Su1, Efi Dwi Indari1, Sigrid Bernstorff2, and Peter Müller-Buschbaum1 — 1TU München, Physik-Deptartment, LS Funktionelle Materialien, James-Franck-Str. 1, 85748 Garching — 2Elettra Sincrotrone Trieste, 34012 Basovizza, Italy
As a convenient pathway to ever more efficient polymer-based solar cells, the use of solvent additives has proven to boost the power conversion efficiencies of several low-bandgap polymer:fullerene systems. The strong improvement of solar cell characteristics is thereby mostly related to a drastic change in nano morphology of the active blend layers induced by the use of solvent additives. It is, however, not yet fully understood how the use of certain solvent additives influences the morphology and the stability of the specific blend layers.
In this work, we investigate the morphological changes of PCPDTBT:PC71BM films induced by the use of 1,8-octanedithiol by means of grazing incidence small and wide angle x-ray scattering and X-ray reflectivity and find that ODT enhances micro phase separation and consequently polymer crystallization. The findings are complemented by UV/Vis and photoluminescence spectroscopy. Furthermore, we show that the optical characteristics of blend films with ODT are highly unstable on a timescale of days.