A High‐Performance Organic Photovoltaic System with Versatile Solution Processability

Abstract Recently developed organic photovoltaic (OPV) materials have simultaneously closed the gaps in efficiency, stability, and cost for single‐junction devices. Nonetheless, the developed OPV materials still pose big challenges in meeting the requirements for practical applications, especially regarding the prevalent issues of solution processability. Herein, a highly efficient polymer donor, named DP3, incorporating an electron‐rich benzo[1,2‐b:4,5‐b′]dithiophene unit as well as two similar and simple acceptor units is presented. Its primary objective is to enhance the interchain and/or intrachain interactions and ultimately fine‐tune bulk‐heterojunction microstructure. The DP3:L8‐BO system demonstrates the highest power conversion efficiency (PCE) of 19.12%. This system also exhibits high‐performance devices with over 18% efficiencies for five batches with various molecular weights (23.6–80.8 KDa), six different blend thicknesses (95–308 nm), differenced coating speeds (3.0–29.1 m min −1 ), with promising PCEs of 18.65% and 15.53% for toluene‐processed small‐area (0.029 cm 2 ) cells and large‐area (15.40 cm 2 ) modules, thereby demonstrating versatile solution processability of the designed DP3:L8‐BO system that is a strong candidate for commercial applications.