Resonant Soft X-Ray Scattering Unravels The Hierarchical Morphology Of Nanostructured Bulk Heterojunction Photovoltaic Thin Films

Resonant soft x-ray scattering at the carbon K edge is shown to be an unambiguous approach to evaluate the phase segregation between donor and acceptor phases across the grooves of a laser-induced periodic surface nanostructure on a paradigmatic poly(3-hexylthiophene)/fullerene bulk heterojunction. By taking advantage of the use of polarized soft x rays, the results provide direct evidence that the formation of the nanostructure on the surface of the heterojunction induces not only additional phase separation of the two components but also a preferential directional arrangement of the different phases.