Green-Solvent-Processable Organic Photovoltaics with High Performances Enabled by Asymmetric Non-Fullerene Acceptors

In this work, two asymmetric non-fullerene acceptors (NFAs), BTP-EHBO-4F and BTP-PHD-4F, are designed to be applied in green-solvent-processable organic photovoltaics (OPVs). BTP-EHBO-4F and BTP-PHD-4F show good solubilities in green solvent o-xylene. As a result, PM6:BTP-EHBO-4F-based devices exhibit outstanding photovoltaic performances using o-xylene as a solvent. By comparison, due to the poor solubility of Y6 in o-xylene, PM6:Y6-based devices show poor performances. Owing to the favorable phase separation, molecule packing, and orientation observed from atomic force microscopy (AFM) and grazing- incidence wide-angle X-ray scattering (GIWAXS) measurements, PM6:BTP-PHD-4F-based devices demonstrate a PCE of 15.91% with a V-OC of 0.87 V, a J(SC) of 25.64 mA/cm(2), and an FF of 71.34%. Moreover, PM6:BTP-EHBO-4F-based devices exhibit an impressive PCE of 16.82% with a V-OC of 0.85 V, a J(SC) of 26.12 mA/cm(2), and an FF of 75.78%, which is outstanding for OPVs using o-xylene as a solvent.

Automated summary

Two asymmetric non-fullerene acceptors, BTP-EHBO-4F and BTP-PHD-4F, were designed and applied in green-solvent-processable organic photovoltaics (OPVs), demonstrating outstanding performance with o-xylene as the solvent. The devices based on these acceptors showed high power conversion efficiencies and excellent solubility compared to devices using Y6 as the acceptor. This was attributed to favorable phase separation, molecule packing, and orientation observed from AFM and GIWAXS measurements.