College of Chemistry and Chemical Engineering Central South University Changsha 410083 Hunan China;
Guangxi Key Laboratory of Electrochemical and Magneto-Chemical Functional Materials College of Chemistry and Bioengineering Guilin University of Technology Guilin 541004 Guangxi China;
Near-infrared electron acceptor Y9; Ladder-type heptacyclic fused ring; Non-fullerene electron acceptors; High-performance OSCs;