A-D-A-type electron acceptors based on pyrrole-containing ladder-type heteroarenes for organic solar cells

Abstract

<p>Organic solar cells (OSCs) have undergone rapid development and achieved significant breakthroughs in power conversion efficiencies, largely due to the emergence of nonfullerene acceptors (NFAs) with ladder-type multifused-ring structures. Over the past few years, huge efforts have been devoted to synthesizing new ladder-type donor cores via rational molecular design, as it can directly dictate most of the OSC-related physicochemical and optoelectronic properties of NFAs. Among the numerous reported ladder-type donor cores with diverse chemical structures, those containing pyrrole rings are becoming the preferred building blocks for the development of high-performance NFAs due to their intriguing physicochemical properties and unique molecular stacking. To date, most of the state-of-the-art NFAs (e.g., Y-series and M-series acceptors) use pyrrole-containing ladder-type heteroarenes as the donor cores. In this review, we summarize acceptor-donor-acceptor (A-D-A)-type NFAs based on pyrrole-containing ladder-type heteroarenes with detailed discussion of the relationships between molecular structures and device performance. We also provide a brief summary of common synthetic strategies for pyrrole-containing ladder-type heteroarenes. Finally, the remaining challenges and the key research directions in the near future are proposed in the hope of providing some useful insights for the further rational design of novel pyrrole-containing ladder-type building blocks and corresponding high-performance NFA materials.</p>