Doping Manipulation of Donor/Acceptor by Perovskite Quantum Dots Enables >20.5% Organic Nonfullerene Solar Cells

Organic nonfullerene solar cells (ONSCs) have achieved remarkable progress, with power conversion efficiency (PCE) now surpassing 20%. To further improve the device performance, herein, we demonstrate a facile doping strategy using emerging perovskite quantum dots (QDs), which is anticipated to address critical issues like high exciton binding energy and limited charge transport. In a typical sequentially deposited planar heterojunction (PHJ) ONSCs, FAPbI₃ QDs were introduced into the donor polymer (D18) and acceptor molecule (L8BO) layers separately, which enables precise manipulation of the vertical doping and decouples the influence of QDs on donor/acceptor. Comprehensive characterizations reveal that the FAPbI₃ QD doping reduces energy disorder, enhances crystallinity, and promotes cascade energy alignment, thereby facilitating exciton dissociation and charge transport. Moreover, FAPbI₃ QDs act as energy mediators, prolonging carrier lifetime and suppressing non-radiative recombination. The optimal D18/L8BO device with simultaneous doping of donor/acceptor achieves a best PCE of 20.55% with a high fill factor exceeding 82%. We also demonstrate the application of QD doping strategy in varying representative donor/acceptor systems, paving a new avenue for minimizing energy loss and advancing the efficiency of ONSCs.