Non‐Halogenated Solvent‐Processed Organic Solar Cells with Efficiencies Exceeding 20.0% and 110 cm2 Modules Exceeding 13% Enabled by Film‐Forming Dynamics Engineering

Abstract The efficiency of small‐area organic solar cells (OSCs) has now exceeded 20%, while mini‐modules have achieved efficiencies of over 17%. However, the performance of large area modules over 100 cm 2 still lags behind, largely due to the limitation of precisely controlling the film formation dynamics to achieve optimal crystallinity and nanomorphology. In this study, phase separation and polymer rheology are synergistically investigated during film formation. Using computational fluid dynamics (CFD) simulations and theoretical calculations, the film formation dynamics are thoroughly investigated in large‐area modules and propose a heat‐enhanced fast morphological evolution strategy (HF). This method mitigates excessive phase separation during large‐area film deposition, reduces non‐radiative recombination, and enhances charge carrier transport. Devices based on PM1:L8‐BO:BTP‐eC9 processed using a non‐halogenated high‐boiling point solvent exhibit a power conversion efficiency (PCE) of 20.3%, with the corresponding 110 cm 2 (active area of 100 cm 2 ) module achieving an efficiency of 13.1% (certified PCE of 12.7%). Finally, the potential applications of organic solar cell modules in environmental protection and medical fields are demonstrated.