Imaging the Multi-Temporal Photo-Carrier Dynamics at the Nanometer Scale in Organic and Inorganic Solar Cells

Understanding the interplay between the nanostructure and photo-transport mechanisms is central for the development of many emerging photovoltaic technologies. In recent years. there has been an increasing focus on the need to probe the photo-carrier dynamics at the nanometer scare. Recently we demonstrated that non-contort atomic force microscopy combined with kelvin probe force microscopy under frequent' modulated illumination (FMI-KPFM) can be used to map two-dimensional images of the surface photo-soltage dynamics pith a sub-10 nnm lateral resolution. Here, a detailed overview of this approach including operating principle. instrumental aspects and data treatment will be given. The capability of FMI-KPFM to map spatial variations of the minority carrier lifetime is demonstrated in the case of silicon nanocrystal-based third generation solar cells. The accuracy of the post-data acquisition processing is discussed by analyzing the evolution of the dynamical contrasts as a function of the illumination intensity in organic bulk heterojunction thin films.