Boosting Organic Photovoltaic Performance Over 11% Efficiency With Photoconductive Fullerene Interfacial Modifier

A interfacial modifier, [5,6]‐open azafulleroid (OPCBM) is utilized to engineer the organics–metal oxide heterojunction of inverted organic photovoltaics (OPVs). Mechanistic studies disclose that the OPCBM treatment not only passivates the metal oxide surface defects, but also improves energetic alignment and conductivity of interlayer due to the excited charge transfer characteristics from azafulleroid to ZnO x . With the assistance of π‐orbital hybridization from fullerene to the beneath ZnO x (through anchoring group), the electronic coupling and charge transfer from organics to metal oxide are effectively enhanced through the mediation of OPCBM modifier. It enables the overall internal quantum efficiency (IQE) approaching 100% and fill factor of 0.77 for the PTB7‐Th:PC 71 BM based inverted OPVs, with the best PCE as high as 11.3%.