Exciton dynamics in self-assembled molecular nanotubes

Photosynthetic systems that exist in plants, algae and some bacteria are Earth’s powerhouse by harnessing its most abundant energy source: sunlight. As one of the key elements, they employ a functional nano-machinery that is typically built from many thousands of autonomously assembled molecules: so-called light-harvesting antennae. In billions of years of evolution, nature has engineered these systems to maximize light-absorption and enable photosynthesis under physiological (warm and humid) conditions that would be considered adverse to most lab-based applications. In order to replicate nature’s design principles for light-harvesting antennae for potential applications, the essential functional elements have to be identified and their working principles understood. Inspired by the success of natural light-harvesting antennae, artificial (man-made) systems that closely resemble the structure of their natural counterparts, have recently experienced great attention. These synthetic analogues feature a high degree of internal homogeneity (i.e., different systems are identical), while also being easier to produce, control and modify than the natural systems. In this Thesis, we study how one of such systems, double-walled molecular nanotubes react to light, how the absorbed energy is transported, and how the energy transport is affected by the structure and dimensionality of the system. Working hand in hand with molecular dynamics simulations and theoretical models, our findings pave the way to optimizing and incorporating such systems in (opto)electronic devices and light-harvesting applications.