The present study, reporting time-resolved investigations of polymer-based films for plastic photovoltaics, particularly focuses on aging related to the devices interface properties. The unconventional approach used is based on an in situ cross-monitoring of the films structural/morphological properties. For this propose, Energy Dispersive X-ray Reflectivity and Diffraction techniques were used in synergy with atomic force microscopy analysis. In this way, the meso-scale modifications of the organic film bulk, surface and buried interface with the electrode, were observed directly. As a result of such non-destructive characterization, access to the concomitant chemical-physical processes, occurring to the cell active component during illumination and related to degradation and reliability issues, is gained. (C) 2010 Elsevier B.V. All rights reserved.