Enhancing Performance and Stability of p-i-n Perovskite Solar Cells with Ag-Cu Codeposited Alloy Electrodes

In the development of back electrodes for perovskite solar cells (PSCs), the major challenges are stability and cost. To address this, we present an innovative approach: Simultaneous evaporation of two independently controlled sources of metal materials was performed to achieve a uniform distribution of the alloy electrodes. In this study, Ag-Cu alloys (the molar ratio of Ag/Cu is 7/3) with a high-index crystal face (111) and a work function matching perovskite were prepared using a codeposition technique. These properties mitigate nonradiative carrier recombination at the interface and reduce the energy barrier for carrier migration. Consequently, compared to Ag based PSCs (22.77%), the implementation of Ag-Cu alloy (Ag/Cu is 7/3)-based PSCs resulted in a power conversion efficiency of 23.72%. In a 1500 h tracking test in ambient air, the Ag-Cu alloy (Ag/Cu is 7/3)-based PSCs maintained their initial efficiency of 86%. This can be attributed to almost no migration of elements from the Ag-Cu alloy electrode to the perovskite layer. Our work presents a vital strategy for improving the stability of PSCs and reducing the costs associated with the back electrode in PSCs.