Dresden 2017 – wissenschaftliches Programm
CPP 32.5: Vortrag
Mittwoch, 22. März 2017, 10:30–10:45, CHE 91
Influence of bulk heterojunction morphology on performances of organic solar cells — •Vladislav Jovanov, Hirwa Hippolyte, Arne Müller, Nivedita Yumnam, and Veit Wagner — Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
The bulk heterojunction morphology of solution processed organic solar cells can be determined by using atomic force microscopy phase imaging as we have demonstrated in our previous studies. The energy dissipated in the cantilever tip interaction with the film surface depends on the material that is present at the surface. Consequently, phase contrast is observed if different materials are forming the film surface. In this study, we have investigated the influence of a bulk heterojunction morphology on the electrical properties of organic solar cells. We have chosen a blend mixture of polymer PTB7 (donor) and fullerene PCBM (acceptor) deposited from DCB/DIO solution as a materials system. In the first step, we have measured the morphologies of bulk heterojunction for different concentrations of the polymer and fullerene material. The determined structure is correlated to the electrical properties of solar cells such as short circuit current, fill factor and series resistance. The results show that bulk heterojunction morphology is crucial not only for the dissociation of generated excitons, but also for the transport of the free charge carries. Finally, we discuss the optimal organization of polymer and acceptor material.