Chapter 10 - Nanostructure and Nanomorphology Engineering in Polymer Solar Cells

Abstract

This chapter delineates nanostructure and nanomorphology engineering in polymer solar cells. Solar cells based on conjugated polymers have been a rapidly developing area of research during the past decade. Because photo-excitations in conjugated polymers show diffusion lengths of only around 5–20 nm, the structure of the polymeric nanophase within the photoactive layer has a large influence on the device properties and the solar power conversion efficiency. This chapter addresses different architectures of polymer solar cells and the influence of their design on solar cell properties. Thereafter, it concentrates on polymer–fullerene bulk heterojunction solar cells and the engineering of their nanostructure toward improved power conversion efficiencies. Bulk heterojunctions constitute intimate blends of organic donor and acceptor materials that allow for efficient charge separation throughout the photo-active layer and provide independent pathways to transport the charge carriers to the contacts. Domains of donor and acceptor materials serve as hole and electron conducting nanophases respectively. Finally, a viewpoint is presented with the focus on the engineering of ordered bulk heterojunctions based on conjugated polymers in combination with inorganic scaffolds or diblock copolymers.