Enhanced Corrosion Resistance of Ag Electrode Through Ionized 2-Mercaptobenzothiazole in Inverted Perovskite Solar Cells

The utilization of Ag electrodes in inverted perovskite solar cells (PSCs) is prevalent; however, their inherent reactivity and corrosive characteristics toward perovskite materials often lead to significant stability concerns. Here, 1-ethyl-3-methyl-1h-imidazolium 2-mercaptobenzothiazole (EM) ionic liquid is designed and introduce it into the bathocuproine (BCP) barrier layer to mitigate the potential chemical corrosion of the Ag electrode by the perovskite layer. EM forms multiple interaction modes through the coordination of two types of bonds, C─N, C═N, and C─S, and chelation with Ag, resulting in the formation of a dense chemical anti-corrosion layer on the Ag surface. By raising the Ag electrode's corrosion potential and decreasing its corrosion current, the occurrence of chemical reactions and corrosion of the Ag electrode by the perovskite layer is effectively suppressed. Additionally, the ionized EM optimizes the band structure and conductivity of BCP and enhances the electron transfer capability at the electron transport layer/Ag interface. The BCP:EM-based inverted PSCs exhibit an efficiency of 25.11% and excellent stability. Under continuous operation at 45 °C and one sun illumination, the encapsulated device maintains 85.6% of its initial efficiency after 1000 h at the maximum power point.