Optimizing Microstructure Morphology and Reducing Electronic Losses in 1 cm² Polymer Solar Cells to Achieve Efficiency over 15%

The successful demonstration of high-performance organic solar cells (OSCs) on a relatively large area is vital for their industrial viability and future application. When the device area is enlarged from several mm2 to the scale of >1 cm2, critical losses caused by film inhomogeneity or defects in the photoactive layer strongly restrict the performance and reproducibility of OSCs. In this work, we demonstrate that through delicate optimization of a photoactive layer and minimization of optoelectronic losses, an impressive external quantum efficiency maximum up to 88% and an internal quantum efficiency peak of 97% are achieved for nonfullerene OSCs. Further incorporating fullerene as the third component into the photoactive layer optimizes the microstructure morphology, enabling large-scale devices with an area of >1.1 cm2, surpassing the 15% efficiency milestone. The exciting results demonstrated in this work highlight the strategic priority to minimize losses through both materials and electronic engineering toward high-performance large-area OSCs.