Designing High-Performance Nonfused Ring Electron Acceptors <i>via</i> Synergistically Adjusting Side Chains and Electron-Withdrawing End-Groups
Yan Zhang, Cai’e Zhang, Andong Zhang, Hongbo Wu, Guangliu Ran, Yuanyuan Zhou, Xiaodong Wang, Cuihong Li, Yahui Liu, Chuluo Yang, Zheng Tang, Wenkai Zhang, Zhishan Bo
Abstract
Three nonfused ring electron acceptors, Hexyl-0F, Isopropyl-0F, and Isopropyl-2F, are designed and synthesized. Unlike Hexyl-0F, Isopropyl-0F with two sterically hindered 2,4,6-triisopropyl-phenyl groups is highly soluble, which provides a good opportunity for solution processability. Compared with Isopropyl-0F, Isopropyl-2F with fluorinated end-groups exhibits red-shifted absorption. Due to these synergistic adjustment, Isopropyl-2F-based devices displayed a high power conversion efficiency of 12.55%, higher than that of Isopropyl-0F (9.49%). The result demonstrates that the introduction of large steric substituents in the π-bridge units and electron-withdrawing end-groups plays a positive role in the construction of high-efficiency nonfused ring electron acceptors.