Enhancing the electron blocking ability of n-type MoO3 by doping with p-type NiOx for efficient nonfullerene polymer solar cells

MoO3 is a promising n-type anode interfacial layer (AIL) with high work function for polymer solar cells (PSCs). However, due to the limited electron blocking ability of n-type metal oxide, the interfacial recombination occurs inevitably in the MoO3/organic interface. Herein, we for the first time strategically introduced minimal amount of p-type NiOx into n-type MoO3 to enhance the electron blocking ability of AIL. The MoO3 doped with NiOx layer (MoO3:NiOx) is highly transparent with a conduction band of 3.25 eV and a work function of 5.10 eV, which prolongs the electron lifetime of PBDB-T:IT-M based device from 0.63 to 5.05 mu s. Benefiting from the prolonged lifetime and enhanced charge collection of MoO3:NiOx AIL, the average power conversion efficiency (PCE) of PBDB-T:IT-M based devices is significantly improved to 10.81%, much higher than that of control devices with PEDOT:PSS (9.79%), MoO3 (8.97%) and NiOx (9.51%) AILs. Our findings provide a new approach to tuning the energy level of cost-efficient and simply processed metal oxide interfacial materials for high performance and stable nonfullerene PSCs.