A High-Performance Organic Photovoltaic System with Versatile Solution Processability.

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.