Nano Energy Research

Electrochemically directed binding of p-electron-rich molecules and nanoobjects at surfaces

Principal investigator: Prof. Dr. Gunther Wittstock
Collaboration: Prof. Dr. Rüdiger Beckhaus, Prof. Dr. Jens Christoffers

While the charge transfer in organic solar cells can be described using concepts of solid state physics, energy conversion in biological light harvesting systems depends on structure and supramolecular orientation of molecular building blocks and can be influenced greatly by design of optimized building blocks. In this project new approaches will be explored for linking molecular functional units to electrode surfaces. The electrodes surfaces serves as a platform for immobilization but also for addressing the functional units by electrochemical processes.

Molecular functional units will be synthesized in the Beckhaus group. The Christoffers groups will provide dues based on diaminoterephthalic acid serving as a scaffold for the attachment of up to four effectors to a central chromophor. The attachment to the surface will be made via a linker and silane or thiol functionalities. Three binding sites are available for functional units. The reaction at the surface will be followed electrochemically, by photoelectron spectroscopy and infrared reflection absorption spectroscopy. Because the scaffold is a fluorescent dye itself changing its emission depending on the functionalization, the progress of the reaction can also be followed by fluorescent spectroscopy in a very elegant way. The aim is to connect two different entities (e.g. a p electron-rich molecule and an plasmonically active nanoparticle at one scaffold and to study the energetic interaction between the two units by spectroscopic means. Such systems would provide an excellent basis for electron transfer reaction for energy harvesting used for electricity generation, selective chemical conversions or sensory purposes if the scaffold is equipped with biological or biomimetic receptors.