Modular artificial photosystems based on polymers

• Applicant: Dr. Michael Jäger
• Subject Area: Preparatory and Physical Chemistry of Polymers
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 426988087

This research proposal is dedicated to create artificial molecular photosystems and to explore their potential in energy conversion schemes. In order to reach this goal, a modular toolbox-approach will be followed, which previously testified a significantly reduced synthetic effort. The desired function is based on the disconnection of elementary steps (energy- and electron transfer) by tailored building blocks – which enable the guided development of polymer-based architectures. The choice and selection of the many conceivable structures originates from the inherent optical and electrochemical properties, which are to be combined in due course. The light-induced charge separation is of key importance albeit the assembly strategy can be adapted to the needs of other fields of applications. In the first work package, the constitutional building blocks will be synthesized, which differ in their molecular structure. Moreover, polymerizable groups as well as solubility-promoting groups will be introduced, which are required in the following packages.In the second work package, molecular architectures are to be assembled via polymerization of electrochemically active building blocks. The obtained electron- and hole-transporting polymers will be attached t in the final two steps to a dye unit. Noteworthily, the facile modular synthesis of substance libraries is ensured, which is synthetically very demanding in case of related molecular assemblies following a classical approach. In the third work package, the light-induced charge separation and recombination thereof is to be explored using time-resolved spectroscopy. Hence various molecular parameters will be explored (e.g. chain length, kind of conjugation, internal charge cascades), in order to minimize the recombination. The studies embark from investigation in solution towards the solid state via film formation, in order to evaluate the potential for descending projects and proposals.The aim and benefit of this research project is to establish a modular platform on a molecular level, in order to create and to control electric charges and excited states on a nanoscopic level. Such control is relevant for many applications of energy conversion, e.g. coupled catalytic reactions, molecular motion, or to generate an external electrochemical potential. Noteworthily, the modular character permits the replacement of individual components by better-suited ones in a straight forward fashion, which is desirable also for the design of other molecular architectures and founds the basis for other applications and further descending projects.

• DFG Programme: Research Grants