Design and control of organic semiconductors and their nanostructures for polymer–fullerene-based photovoltaic devices

Abstract

The polymer solar cell (PSC) technology has continued to be developed, and the power conversion efficiency (PCE) has now exceeded 10%. The rapid improvement of PCEs in the last decade has mainly resulted from versatile synthetic efforts for conjugated polymers as electron-donors and fullerene derivatives as electron-acceptors. This Feature Article highlights recent exploration of unique, attractive building blocks, i.e., quinoidal units, phospholes, porphyrins, and fluorinated aromatic rings, which can be incorporated into low bandgap conjugated polymers. As candidates for the next-generation acceptor materials that replace the benchmark acceptor, [6,6]-phenyl-C₆₁-butyric acid methyl ester ([60]PCBM), fullerene bisadduct regioisomers are also overviewed. Furthermore, we summarized recent attempts for the construction of one-dimensionally confined, organic donor–acceptor heterojunction nanorods and their applications to photovoltaic and optoelectronic devices. The topics in this article are not intended to cover an exhaustive list of PSC research studies, but involve the fundamental aspect to stimulate further studies for getting new insights into the structure–property relationship in PSC devices.