Asymmetric Side-Group Engineering of Nonfused Ring Electron Acceptors for High-Efficiency Thick-Film Organic Solar Cells
Dawei Li, Nan Wei, Yanan Chen, Xiaodong Wang, Xu Han, Ziqing Bian, Xinyuan Zhang, Zhe Zhang, Wenkai Zhang, Xinjun Xu, Cuihong Li, Yahui Liu, Hao Lu, Zhishan Bo
Abstract
A nonfused ring electron acceptor (NFREA), designated as TT-Ph-C6, has been synthesized with the aim of enhancing the power conversion efficiency (PCE) of organic solar cells (OSCs). By integrating asymmetric phenylalkylamino side groups, TT-Ph-C6 demonstrates excellent solubility and its crystal structure exhibits compact packing structures with a three-dimensional molecular stacking network. These structural attributes markedly promote exciton diffusion and charge carrier mobility, particularly advantageous for the fabrication of thick-film devices. TT-Ph-C6-based devices have attained a PCE of 18.01% at a film thickness of 100 nm, and even at a film thickness of 300 nm, the PCE remains at 14.64%, surpassing that of devices based on 2BTh-2F. These remarkable properties position TT-Ph-C6 as a highly promising NFREA material for boosting the efficiency of OSCs.