CONTROL · Controlling delocalisation and funnelling of excited state energy in the strong coupling regime in molecular systems

A fundamental physical property of A fundamental physical property of matter is its ability to interact with light. This is not only the basis of fascinating concepts like seeing colours, but also the foundation of life and advanced technologies. Yet, some basic physical laws hamper possible utilisations. It is therefore of great importance to examine how to bend these laws, how to bypass them and by so doing open up new opportunities for novel applications. This is exactly what this project aims to do.Plant leaves are green because they absorb visible light. However, it is less known that this light-matter interaction can be enhanced to the point where it is so strong that the photon and molecule cannot be regarded as separate entities, but as a combined system with unique properties. Nature uses strong pigment-pigment interactions to rapidly funnel absorbed sunlight to the photosynthetic reaction centre. However, up to now, organic solar cells do not take advantage of such quantum processes to enhance light to electricity conversion.In CONTROL, I will use a chemical viewpoint to develop unique molecules optimised for strong light-matter interactions, and with these examine excited state processes of strongly coupled systems. My aim is to funnel excitation energy to charge transfer states in an organic heterojunction using the delocalised nature of hybrid light-matter states. This interaction enables transport of excitation energy over distances much longer than have been previously considered feasible. Using time-resolved optical spectroscopy and photoconductivity, I will systematically analyse the interaction between delocalised hybrid states and localised charge transfer states, allowing design criteria to be formulated. The outcome of this research program will be the description and mechanistic revelation of a novel quantum physical phenomenon that can enable development of organic solar cells from simple layered structures with unprecedented efficiencies.