Utilizing Ternary Strategy to Reduce the Influence of Polymer Batch‐to‐Batch Variation in Organic Solar Cells

Despite producing the best device performances, several major issues such as the batch‐to‐batch variation and low molecular weight ( M w ) optimization greatly hinder the progress for the organic solar cells. Herein, tetraphenylethylene (TPE) as a third component has been added in a series of PM6:Y6 blends with different donor molecular weights (42–129 kDa). Ultimately, ternary devices fabricated by the PM6 with about half the M w (66 and 74 kDa) of the standard donor (129 kDa) produce an excellent power conversion efficiency (PCE) of 15.09% and 15.15% owing to enhanced morphology and charge mobility, as compared to a standard binary PCE of 15.65%, respectively, indicating the possibility of attaining high‐performance attributes from low M w polymers. Furthermore, the TPE inclusion in the 129 kDa binary blend leads to a remarkable PCE of 16.48%. This strategy, therefore, illustrates a relatively simple approach to overcome the batch‐to‐batch variation problem associated with polymers for organic solar cells.