Invited paper: Nanostructures of a mixed donor and acceptor layer in organic photovoltaics

In organic photovoltaics with a mixed donor and acceptor structure, the junction property is directly related to the morphology because charge transportation is determined by the formation of inter penetrating networks. Therefore, structural studies are very important to understand the fundamental problems in mixed donor and acceptor structured OPVs. In this paper, we show how to apply the x-ray scattering method in nanostructural studies of polymer OPVs as well as of small molecular OPVs with a mixed donor and acceptor structure. The results of structural studies about P3HT:PCBM are introduced to make reference to a typical system of polymer based OPVs. In small molecular (SM) OPVs, there is a new method: alternative thermal deposition (ATD) for the mixed donor and acceptor structures is also presented in this paper. The GISAXS study showed better formation of interpenetrating networks in the ATD device in comparison with that of the conventional co-deposited device, which was also confirmed by the improved device performance.