This lecture will present on-going research in physical chemistry, and will focus this year on solar energy conversion. It starts with an introduction about solar cells and artificial photosynthesis, including underlying electron transfer processes. The properties of conjugated polymers and their use in organic solar cells is then discussed. Next, we describe the processing of those organic functional materials and the importance of their solid-state microstructure. This leads to a description of the photo-physical phenomena leading to charge generation in polymer photovoltaic systems, as obtained by ultrafast spectroscopy experiments.