Identifying intermolecular interactions and their role in organic solar cell materials by optical spectroscopy

Organic semiconductors are approaching the 20% threshold for organic solar cells, and novel applications such as organic agri-photovoltaic and organic photo-battiers are emerging. The optoelectronic properties of organic semiconductor thin films, such as exciton dissociation and charge transport, however depend critically on the morphology of the film and the interactions between adjacent chromophores. To advance organic semiconductor applications, it is therefore essential to understand (i) how aggregates form in solutions, and by which principles aggregate formation can be controlled in the film deposition process, and (ii) which role they play for the generation and transport of free charge carriers. In this presentation I will demonstrate how absorption, photoluminescence and pump-probe spectroscopy may be used to identify intermolecular interactions and their impact in aggregates in solution and film.