More than Conformational “Twisting” or “Coplanarity”: Molecular Strategies for Designing High-Efficiency Nonfullerene Organic Solar Cells

Abstract

The power conversion efficiencies (PCEs) of organic solar cells are lower than that of recently emerging perovskite solar cells. Can a PCE of >12% be achieved with single-junction organic solar cells? To achieve a high PCE, much effort has been focused on the design and synthesis of electron-donor materials, including polymers and small molecules, and on innovative solar cell device structures. In this perspective, we focus on a different approach—replacing traditional fullerene acceptors with nonfullerene organic acceptors. This method is an interesting and powerful alternative for achieving more efficient organic solar cells because the molecular structures of organic acceptors can be easily chemically modified and their optoelectronic properties and aggregation behaviors are tunable. However, the film morphology affects charge separation, transport and collection and must therefore be considered when improving the electrical performance of nonfullerene organic solar cells (NF-OSCs). Herein, we discuss ...