Improved Operational Stability of Perovskite Solar Cells via Au Barrier Layer Incorporation

Metal electrode corrosion by halogen species from perovskites causes severe degradation in perovskite solar cells (PSCs). By employing the Au–Ag bilayer top electrode, we show improved operational stability for PSCs compared to devices with a single metal electrode. The optoelectronic property of bilayer electrodes and their influence on device parameters and operational stability are characterized and discussed. Significantly enhanced operational stability (T80 > 200 h) is demonstrated compared to pure Ag metal electrode devices (T40 ≈ 200 h), under maximum power point conditions. The applicability of this strategy is further confirmed by the Au–Al bilayer electrode system. The work not only demonstrates an effective method to prevent metal electrode corrosion and perovskite decomposition but also provides insights into the working principle and degradation of PSCs.