Dresden 2014 – scientific programme
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DS: Fachverband Dünne Schichten
DS 27: Organic Thin Films II
DS 27.6: Talk
Wednesday, April 2, 2014, 16:15–16:30, CHE 91
Study of the structure of solution processed bulk heterojunction organic solar cells — •Thaer Kassar1, Torben Schindler1, Tilo Schmutzler1, Christoph Brabec2, and Tobias Unruh1 — 1LKS FAU, Erlangen, Germany — 2i-MEET FAU,Erlangen, Germany
Solution processed bulk heterojunction polymer solar cells are becoming viable technology due to their potential as a low-cost, printable, and flexible renewable energy source. Little is known about their structure formation and how it can be controlled. It was thought that conjugated polymers and fullerene derivatives separate into pure domains. However, recent reports suggest that intercalation of fullerenes between the side chains of the polymers is possible. Our working group has built a dedicated cell with an integrated doctor blading coater to perform in situ measurements of the evolution of the blend structure during the drying process. To access the 3D structure of the studied thin films from the molecular to the mesoscale, we probe the inner structure through the methods of grazing incidence X-ray diffraction (GIXD) and grazing incidence small angles X-ray scattering (GISAXS). Grazing incidence geometry is used to enhance the scattered intensity and limit it to the films. We exploit SAXS to study the solutions before coating them. We also study ternary cells which overcome the absorption limitation of organic semiconductors and how solvent mixtures, processing additives, thermal/solvent annealing and multilayer stack build-up of the device affect the final dried blend structure. In this talk, first results on the structure formation of active layers of solution processed solar cells will be presented.