Constructing a dual-fiber network in high efficiency organic solar cells via additive-induced supramolecular interactions with both donor and acceptor

Abstract

We designed and synthesized three chlorinated thiazole additives, namely TZ-Cl, TZ-2Cl and TZ-3Cl, which are characterized by an increasing number of chlorine atoms. Our research findings demonstrate the presence of supramolecular interactions between these additives and both polymer donors and non-fullerene acceptors. These interactions gradually intensify with an increasing number of chlorine atoms, thereby facilitating effective modulation of the crystallinity and aggregation states of the donor and acceptor molecules. Notably, the TZ-3Cl promotes a significantly refined dual-fibril interpenetrating network structure within the blend film. This enhanced active layer structure aids in extending exciton diffusion, improving exciton dissociation, and boosting charge transport, while simultaneously minimizing energy losses within the device. As a result, OSCs incorporating TZ-Cl, TZ-2Cl, and TZ-3Cl as additives in the PM6:L8-BO binary system achieved power conversion efficiencies (PCEs) of 18.3%, 18.5%, and 19.8%, respectively. Furthermore, in the PM6:BTP-eC9-4F:DM-F ternary OSC system, we attained a remarkable PCE of 20.2%. Overall, this study introduces a practical and innovative approach for designing high-efficiency OSC additives by leveraging supramolecular principles.