 The use of potassium iodide, Ki3, additives in conjunction with conventional lead sulfide, PBS, matrix ligands has been shown to be effective in reducing surface trap states and enhancing device stability in solar cells. This combination of materials leads to improved performance compared to controlled devices without Ki3 additives, resulting in a power conversion efficiency of 12.1%, which is higher than the controlled devices with Ki additives, 11%. Furthermore, the devices with Ki3 additives retain 94% of their initial efficiency after 20 hours of continuous operation in air, whereas the controlled devices with Ki additives only retained 87%. This article was authored by Longhu, Chi-Li, Sun-Wai-Gwan, and others.