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

Comprehensive Summary 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.