Improved performance for polymer solar cells though photon energy harvesting and down-conversion of Eu3+-induced diblock polymer aggregates (EIPAs)

At present, down-conversion materials and doping active layer materials are effective means to improve the efficiency and stability of polymer solar cells (PSCs). Herein, environmentally friendly and cost-effective Eu3+-induced diblock polymer aggregates (EIPAs) were synthesized by the self-assembly method, and these aggregates were doped into the active layer of various non-fullerene systems, which optimized the morphology and effectively increased the ultraviolet light absorption in the range of 300–450 nm and converted into secondary emission in the visible range. Upon optimization, devices featuring PM6:IT-4F doped with a concentration of 0.2 mg mL−1 EIPAs exhibited a remarkable improvement in power conversion efficiency (PCE) and stability, with a 10.83% increase compared to binary devices, achieving an impressive PCE of 13.82%. This enhanced performance can be attributed to the significant increase in short-circuit current density (JSC) and fill factor (FF) observed in the doped devices. Similar observations have been made with other EIPA-doped devices, further demonstrating the versatility of EIPAs in improving the overall device performance of PSCs.