Minimization of metallic Bi-0 species to increase the efficiency and stability of Ag3BiI6 solar cells via Cu doping

Metallic Pb-0 and uncoordinated Pb+2 species, which are generally observed in thin-film lead-based perovskites during the film production process or solar cell operation, have negative impact on device performance. Minimizing these two defects, it is possible to increase both cell efficiency and long-term stability. The effects of these traps on bismuth-based solar cells are still being investigated. In this study, we added CuBr to minimize metallic Bi-0 species encountered in Ag3BiI(6) solar cells, and increased device efficiency and stability. X-ray photoelectron spectroscopy (XPS) measurements have shown that the addition of a small amount of CuBr minimizes the formation of a small amount of metallic Bi-0 from the manufacturing process. The devices produced with the highest efficiency CuBr-AgI-BiI3 system increased the performance of the control device from 0.4% to 0.7% and substantially improved durability. During the 7-week stability test, we observed an 40% decrease in the initial efficiency of the control device, while we noticed an 11.4% decrease in the efficiency when adding small amounts of CuBr. This study offers a highly effective approach that involves Cu doping to minimize metallic Bi-0 species that appear in the production process of Ag3BiI(6) solar cells and increase device efficiency and stability.