Symmetry-induced orderly assembly achieving high-performance perylene diimide-based nonfullerene organic solar cells

Controllable assembly of organic semiconductors has opened an avenue for an in-depth perception of their structure–property relationships; however, a detailed investigation of their molecular controllability remains challenging. Discerning the assembly of organic semiconductors could enable the attainment of a significant improvement of performance. Here, we report the fabrication of efficient nonfullerene organic solar cells (OSCs) based on two isomeric perylene diimide (PDI)fused corannulene acceptors, namely, corannurylene pentapetalae (CRP). A single-crystal analysis demonstrated that differentially symmetric isomers such as CRP-1 and CRP-2 display various assembly framework structures. Both isomeric CRP acceptor-based solar cells showed excellent power conversion efficiencies matching a medium bandgap polymer donor (P3TEA). Compared with CRP-2, a high symmetry-induced orderly assembly endowed CRP-1 with a higher efficiency of 11.2%, which is the maximum performance of PDI-based OSCs reported to date. This study sheds light on designing high-performance organic semiconductors allowing for symmetric orderly assembly.