Interfacial stabilization for inverted perovskite solar cells with long-term stability

Abstract Perovskite solar cells (PSCs) commonly exhibit significant performance degradation due to ion migration through the top charge transport layer and ultimately metal electrode corrosion. Here, we demonstrate an interfacial management strategy using a boron chloride subphthalocyanine (Cl6SubPc)/fullerene electron-transport layer, which not only passivates the interfacial defects in the perovskite, but also suppresses halide diffusion as evidenced by multiple techniques, including visual element mapping by electron energy loss spectroscopy. As a result, we obtain inverted PSCs with an efficiency of 22.0% (21.3% certified), shelf life of 7000 hours, T80 of 816 h under damp heat stress (compared to less than 20 h without Cl6SubPc), and initial performance retention of 98% after 2000 hours at 80 oC in inert environment, 90% after 2034 h of illumination and MPP tracking in ambient for encapsulated devices and 95% after 1272 h outdoor testing ISOS-O-1, which is among the top device performance for the inverted PSCs.