Aggregation modulation of electron-donating polymer towards certified short-circuit current of 29.86 mA cm−2 in organic photovoltaics

Molecular aggregation in thin films demonstrates a profound effect on the photovoltaic performance of organic photovoltaics (OPVs). Here, we develop a novel two-dimensional atomic crystal CdPS₃, and comprehensively investigate its effect on the thin film aggregation and photovoltaic performance of PM6:Y6 −based OPVs. CdPS₃ tends to be distributed in PM6 domain, inducing a J- to H-aggregation transformation of PM6 molecules. H-aggregation resulted in finer phase separation, tighter molecular packing in PM6:Y6 blend membranes. Such morphology-aggregation feature contributed to efficient exciton dissociation and carrier generation, as well as ultrafast carrier transport and collection in the device. Consequently, PM6:Y6 −based OPVs obtained a certified short-circuit current (J_SC) of 29.86 mA cm⁻², representing the highest J_SC values of so far observed OPVs. Our work highlights the potential of aggregate regulation of polymer donors for enhancing J_SC in OPVs.