Regulating Electron-Phonon Coupling by Solid Additive for Efficient Organic Solar Cells

• Published in: Angewandte Chemie International Edition 2024-10, p.e202413309
• Main Authors: Ge, Zhongwei, Qiao, Jiawei, Li, Yun, Song, Jiali, Duan, Xiaopeng, Fu, Zhen, Hu, Haixia, Yang, Renqiang, Yin, Hang, Hao, Xiaotao, Sun, Yanming
• Format: Article
• Language: English
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202413309

Strong electron-phonon coupling can hinder exciton transport and induce undesirable non-radiative recombination, resulting in a shortened exciton diffusion distance and constrained exciton dissociation in organic solar cells (OSCs). Therefore, suppressing electron-phonon coupling is crucially important for achieve high-performance OSCs. Here, we employ the solid additive to regulating electron-phonon coupling in OSCs. The planar configuration of SA1 confers a significant advantage in suppressing lattice vibrations in the active layers, reducing the scattering of excitons by phonons caused by lattice vibrations. Consequently, a slow but sustained hole transfer process is identified in the SA1-assisted film, indicating an enhancement in hole transfer efficiency. Prolonged exciton diffusion length and exciton lifetime are achieved in the blend film processed with SA1, attributed to a low non-radiative recombination rate and low energetic disorder for charge carrier transport. As a result, a high efficiency of 20% was achieved for ternary device with a remarkable short-circuit current. This work highlights the important role of suppressing electron-phonon coupling in improving the photovoltaic performance of OSCs.