Non-Halogenated Solvent Processed Ternary All-Polymer Solar Cell with PCE of 18.55% Enabled by Two Compatible Polymer Acceptors^†

Herein, a theory-guided ternary construction case on boosting power conversion efficiency (PCE) for all-polymer solar cell (all-PSC) is reported, where guest acceptor's characteristics include high miscibility with host polymer acceptor, significantly larger optical bandgap, and improved luminescence. Consequently, with only 10 wt% PFFO-Th (third component) addition, the PCE of binary control is promoted to 18.55% from 16.69%, a 11.1% relative increase, demonstrating the great effectiveness of this ternary strategy. Besides, the realized 18.55% efficiency is at state-of-the-art level of all-PSCs processed by ortho-xylene, a widely acknowledged green non- halogenated solvent by the field. This study shares new thought on designing high-performance photovoltaic devices with reduced energy losses and favorable charge dynamics, which would nourish future development on all-PSCs, and even other organic electronics.