Solar energy conversion must arguably play a central role in sustainably providing large-scale power to a growing global population currently undergoing a massive surge in industrialization. At present, this goal remains elusive owing to the absence of means for economical solar power generation. Organic and hybrid organic / inorganic photovoltaic cells (OPV) have the potential to fill this gap, but are currently unable to meet the efficiency required for a significant impact on the energy market. The delicate balance between high interfacial area required for efficient exciton dissociation and high mobility of both types of carriers poses fundamental challenges to device architecture that require novel spectroscopic insights on microscopic length-scales. Scanning photoionization microscopy (SPIM) is capable of providing frontier orbital position at high spatial resolution, thus generating a detailed map of interfacial electronic structure at sub-micron length-scales. We will discuss recent advances to implement this form of microscopy in the context of nano- and meso-structured hybrid materials for solar energy conversion.