Spectroscopy of Isolated Chromophore Ensembles (SPICE)

Molecular complexes, aggregates and larger nanostructures made of organic molecules form the basis in organic photovoltaic and optoelectronic devices. A better understanding of the photoexcitation-driven processes in these systems is thus of high interest and may help optimizing designs to achieve higher efficiencies and better functionalities. The dynamics in these multi-chromophoric systems are dominated by cooperative processes and collective effects. Electronic excitation of the system leads to the formation of delocalized excitons. Important questions are how excitation energy is transported through the molecular networks (exciton migration), avoiding loss processes (exciton annihilation) and exploring new schemes to enhance performance (exciton fission).

In this project, we follow two unique approaches to study organic chromophore ensembles by matrix-isolation techniques. On the one hand, we study single, isolated species and molecular aggregates prepared inside helium nanodroplets (Fig. 1a). On the other hand, we investigate molecular networks formed on the surface of solid rare gas clusters (Fig. 1b). These well-controlled nanosystems prepared at low temperatures (0.4 – 10 K) allow for flexible tuning of intermolecular and system-bath couplings. The molecular systems can be spectroscopically resolved with a precision, which is challenging to achieve with other methods (Fig. 1c). This allows us to gain a fundamental understanding of the interplay between geometric and energetic structure and its impact on the collective exciton dynamics.

Contact:

Dr. Sebastian Hartweg

Prof. Dr. Frank Stienkemeier

Funding:

Deutsche Forschungsgemeinschaft

RTG DynCAM

Back to research projects