Near-Infrared Fully Nonfused Acceptors with Selenophene Central Core and Halogenated End-Groups for Efficient Organic Solar Cells
Liying Dong, Siyuan Zang, Wanying Feng, Shuaiqi Wang, Xizhe Chu, Bofang Shan, Zhigang Ni, Bin Kan, Qian Zhang
Abstract
Two fully nonfused electron acceptors (FNEAs) were developed, comprising a selenophene central core flanked by halogenated end-groups (fluorine and chlorine derivatives), to probe the structure–property relationships. The chlorinated 4TSe-Cl exhibits a red-shifted absorption and enhanced crystallinity compared with its fluorinated counterpart (4TSe-F). When paired with polymer donor D18, the 4TSe-Cl-based devices delivered a champion power conversion efficiency (PCE) of 13.74%, surpassing those devices based on D18/4TSe-F (12.96%), which is among the best in FNEA-based devices. The superior performance of 4TSe-Cl can be attributed to its better miscibility with D18, formation of a more refined fibrillar-like network structure, improved charge transport properties, and higher carrier mobility in the blend. This work highlights that synergistic modulation of both the central core and end-groups in nonfused electron acceptors is a promising approach toward achieving high-efficiency organic solar cells (OSCs).