Manipulating Aggregation Kinetics toward Efficient All‐Printed Organic Solar Cells

The power conversion efficiencies (PCEs) of all-printed organic solar cells (OSCs) remain inferior to those of spin-coated devices, primarily due to morphological variations within the bulk heterojunction processed via diverse coating/printing techniques. Herein, cyclohexyl is introduced as outer side chains to formulate a non-fullerene acceptor, BTP-Cy, aimed at modulating the molecular aggregation in solution and subsequent film formation kinetics during printing. Investigations demonstrate that BTP-Cy molecule with cyclohexyl side chains exhibits enhanced intermolecular π-π stacking, optimal solution aggregation size, and favorable phase separation. Consequently, PB3:FTCC-Br:BTP-Cy-based OSCs achieve remarkable PCEs of 20.2% and 19.5% via spin-coating and blade-coating, respectively. Furthermore, a 23.6 cm² module exhibits a remarkable efficiency of 16.7%. This study offers a fresh perspective on tailoring the film formation kinetics of photoactive materials during printing through molecular design, paving a novel path to enhance the efficiency of all-printed OSCs.