3D electron diffraction—the missing slice completing nanoscale analysis of organic solar cells in TEM

Abstract Optimizing the performance of organic solar cells hinges on a comprehensive understanding of their nanostructures, yet traditional characterization methods often fall short, delivering incomplete structural snapshots. We introduce elastically filtered 3D electron diffraction as technique to bridge full reciprocal- and real-space structural analysis within a single transmission electron microscope. Using model bulk heterojunction DRCN5T:PC 71 BM, 3D electron diffraction reproduces key structural parameters obtained from grazing-incidence wide-angle X-ray scattering, including lattice spacings, coherence lengths, and mosaicity, while also providing true in-plane access and direct registration with high-resolution imaging, diffraction imaging and nano-spectroscopy on the same sample. Application to another archetypal blend, P3HT:PC 71 BM, demonstrates the generality of the method. Our findings underscore the transformative potential of 3D electron diffraction, particularly in analyzing beam-sensitive organic thin films. The method enables correlative structural characterization of organic solar cells and opens pathways for application to a wide range of other nanostructured materials.