Self-assembly, structure, and optical properties of molecular aggregates

This thesis contains a theoretical research on molecular aggregates which, under the right circumstances, are spontaneously formed by synthetic dye molecus that are dissolved in a solution. In the aggregates, dye molecules are stacked in an ordered way to form for example ring- or cylindrical structures. Because of the close spacing of the dye molecules, the interaction of the aggregates with light differs fundamentally from the interaction between separate dye molecules and light. This makes the aggregates interesting en possibly applyable in new technologies, for example in new types of organic solar cells.

With the help of computer simulations, we have investigated the spontaneous aggregation, the form and internal structure, and the optical properties of the aggregates. First, we have replicated the spontaneous formation of an aggregate on the computer. In this way, we obtained information on the shape of the aggregates and the way in which the dye molecules are stacked to form the aggregate. This information is often unknown, because the aggregates are so small that they are hard to see with a (electron-)microscope. The such obtained information on the structure of the aggregate was then used to calculate the aggregates' optical properties. Our calculations give a deeper insight into the special optical properties of aggregates of dye molecules.