High-Performance Organic Solar Cells Based on a Non-Fullerene Acceptor with a Spiro Core.

Derived from perylenediimide (PDI) building blocks, 3D PDI molecules are considered as a type of promising structure to overcome molecular aggregation, thus improving the performance of organic solar cells. Herein, we report a novel PDI-based derivative, SCPDT-PDI4 , with four PDI units connected to a unique spiro core. Attributed to this novel molecular design, SCPDT-PDI4 exhibits a rigid 3D structure, in which the aggregation tendency of PDI chromophores could be effectively attenuated. Additionally, strong intramolecular charge transfer and high charge mobility are achieved due to the well-conjugated structure and electron-rich property of SCPDT. Therefore, fullerene-free organic solar cells based on SCPDT-PDI4 and PTB7-Th achieve a remarkable high efficiency of 7.11 %. Such an excellent result demonstrates the opportunity of SCPDT to be a promising building block for non-fullerene acceptors.