Аннотация:Polymer nanocomposites based on polyaniline (PANI) complex with polysulfonic acid and graphene were successfully created. Tuning of both the uniformity of the distribution and size of graphene stacks in the PANI complex matrix was performed by thorough selection of graphene of different degree of oxidation. Thin films of the nanocomposites were tested as a buffer layer in organic PV cells. PV cells with the nanocomposite layer demonstrated the enhanced characteristics compared to those with the layer of graphene free PANI-polyacid complex. The power conversion efficiency increased by 37%. The result is explained taking into account the formation of large graphene stacks which define both the surface roughness of the buffer layer and the high conductivity of the buffer layer in the direction perpendicular to its surface.