Iodide Manipulation Using Zinc Additives for Efficient Perovskite Solar Minimodules

Abstract Interstitial iodides are the most important type of defects in perovskite solar cells that limits efficiency and stability. They can be generated during solution, film, and device processing and further accelerate device degradation. Herein, we find that introducing a small amount of an organozinc compound- zinc trifluoromethanesulfinate (Zn(OOSCF 3 ) 2 ) in the perovskite solution can control the iodide defects in resultant perovskites ink and films. CF 3 SOŌ vigorously suppresses molecular iodine formation in the perovskites by reducing it to iodide, while zinc cations can precipitate out excess iodide by forming a Zn-Amine complex so that the iodide interstitials in the resultant perovskite films can be suppressed. The perovskite films using these additives show improved photoluminescence quantum efficiency and reduce deep trap density, despite that zinc cations reduce the perovskite grain size and iodide interstitials. The zinc additives facilitate the formation of more uniform perovskite films on large-area substrates (78-108 cm 2 ) in the blade-coating process. Fabricated minimodules show power conversion efficiencies of 19.60% and 19.21% with aperture areas of 84 and 108 cm 2 , respectively, as certified by National Renewable Energy Laboratory (NREL), the highest efficiency certified for minimodules of these sizes.