Angewandte Chemie | 2021
High-performance Unfused-Ring Electron Acceptors for Organic Solar Cells Enabled by Noncovalent Intramolecular Interactions and End Group Engineering.
Abstract
Unfused-ring electron acceptors (UREAs) have attracted much attention in recent years due to their advantages of simple synthetic routes, high yields and low costs. However, the efficiencies of UREAs based organic solar cells (OSCs) are still far behind those of fused-ring electron acceptors (FREAs). Herein, a series of UREAs with S···O\xa0noncovalent intramolecular interactions were designed and synthesized with a two-step synthetic route. Upon introducing π -extended end-groups into the backbones, the electronic properties, charge transport, film morphology, and energy loss were precisely tuned by fine-tuning the degree of multi-fluorination. As a result, a record PCE of 14.53% in labs and a certified PCE of 13.8% for UREAs based devices were obtained. This contribution demonstrated that combining the strategies of noncovalent conformational locks and π -extended end-group engineering is a simple and effective way to explore high-performance UREAs.