This projects aims to contribute to a better understanding of the relationship between processing conditions, active layer morphology and device performance in polymer solar cells (PSCs). To this end a series of SANS experiments are envisaged, to provide the most detailed understanding possible of the processing-morphology-performance relationships in polymer:fullerene solar cells based on those polymers with the best power conversion efficiencies (PCEs), namely PCDTBT, PTB7 and PBDTTT-EFT. Optimized organic photovoltaic (OPV) processing, with its associated low production costs, would radically change the renewable energy paradigm that is key for opening solar energy to new markets such as those in developing countries where people wouldn?t normally think about investing in and generating their own electricity.