Nanoscale Correlation of Heterogeneous Morphology and Electrical Transport in Nanostructured Organic and Hybrid Solar Cells

The knowledge of correlation between morphology and electrical properties is essential both to understand fundamental physics and to facilitate device optimization. We report a systematic study of the organic blend of PCBM particles and P3HT fibers formed via the thermal annealing method. We use conductive atomic force microscopy (c-AFM) to simultaneously map the surface morphology and collect the electrical current. Cross-section AFM is attempted to get the internal 3D morphology so as to establish its correlation with the electrical properties. The obtained heterogeneity in the current map with a resolution up to 20 nm is attributed to the formation of cross-linked three dimensional fiber network, which is further supported by a three dimensional device model incorporating the geometry of nanowire and the c-AFM tip. Results on the hybrid cell of ZnO nanowires infiltrated with P3HT will also be discussed.