Photovoltaic and optoelectronic materials are often assembled from nanoscale building blocks, such as small organic molecules, quantum dots, or polymers. Different methods can be used to put these building blocks together, but one of the most common and cost-effective methods is deposition from a solution. As solvent evaporates, the individual building blocks get closer together, start to interact, and end up in particular physical arrangements. As components of a system couple together, these physical arrangements can result in disorder and defects, and the group of particles can exhibit collective phenomena that alter the behavior of excitons and carriers in unexpected ways.
 

Research in our lab seeks to adapt time-resolved exciton spectroscopies to the measurement of nanoscale building blocks during their self-assembly. We will measure electronic structure and exciton dynamics in situ and in real-time as irreversible processes occur, such as crystallization, self-assembly, and chemical bond formation. By measuring and comparing how exciton behavior changes during self-assembly using various solution deposition techniques, we develop strategies to control self-assembly to create materials with designer excitonic properties.