2D polarization resolved optical spectroscopy for exploration of conformation, energy transfer and aggregation of macromolecules (conjugated polymers and proteins) within different environments under the goal to contribute to the improvement of organic bulk heterojunction solar cells.

• Applicant: Dr. Daniela Täuber
• Subject Area: Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics ; Electrical Energy Systems, Power Management, Power Electronics, Electrical Machines and Drives ; Experimental and Theoretical Physics of Polymers ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2014 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 256530768

This project will explore conformation and aggregation of macromolecules using recently developed 2D polarization imaging techniques (2D POLIM). The aim of the investigation is to establish new insight into the organization of the studied macromolecules with the prospect for improved applications in organic electronics. The studied objects, one the one hand, will be conjugated polymers, which due to their electronic and optical properties are suitable for organic electronics. Application of 2D POLIM to diluted solutions of conjugated polymers in liquid crystal (LC) matrices will enable us to evaluate the topology of the polymer chains/particles and measure the extend of energy transfer within these objects. In contrast to amorphous polymer matrices, LCs provide a known local structure, which can be controlled by temperature and electric field. Establishing of unambiguous correlations between the chain size, chain conformation, degree of aggregation and energy transfer efficiency is still lacking. Such knowledge is especially important for organic electronics where the polymer chain morphology seems to be the key for the device performance. On the other hand, investigation of biopolymers in living cells and in vitro is expected to provide new insight in the complex pathways of their functionality and organization. Functional structures play a prominent role in cell biology. By extending our research activities to the investigation of biological materials, we expect to find viable clues for the improvement of organic solar cells. Preliminary investigation proved the power of 2D POLIM to resolve structures in biomedical samples to be superior to conventional fluorescence spectroscopy techniques. In cooperation with the Wallenberg Neuroscience Center, Bio-Medical Center, Lund University aggregation states in proteins will be explored. The ability of 2D POLIM to resolve energy transfer together with particle orientations, provides a more direct approach on interaction of proteins than other fluorescence microscopy techniques.From the investigations of both materials, we expect new insight for the improvement of organic bulk heterojunction solar cells. The already existing collaboration with the Swedish Center for Organic Electronics (COE) will provide us with materials to directly test structures and material compositions motivated by the results from our studies.

• DFG Programme: Research Fellowships
• International Connection: Sweden
• Hosts: Professorin Dr. Cecilia Lundberg; Professor Dr. Ivan Scheblykin