Zhang, DongyangKhasnabis, SutriptoWang, WanlongYeddu, VishalMoradi, ShahramAwais, MuhammadNguyen, Hai-DangReinecke, Sean B.Haruta, YukiGodin, RobertTan, FuruiSaidaminov, Makhsud I.2024-05-142024-05-142024Zhang, D., Khasnabis, S., Wang, W., Yeddu, V., Moradi, S., Awais, M., Nguyen, D.-H., Reinecke, S. B., Haruta, Y., Godin, R., Tan, F., & Saidaminov, M. I. (2024). Cadmium‐doping slows trap emptying in ambient‐air blade‐coated formamidinium lead iodide perovskite solar cells. Advanced Energy Materials. https://doi.org/10.1002/aenm.202303858https://doi.org/10.1002/aenm.202303858https://hdl.handle.net/1828/16515Formamidinium lead iodide (FAPbI3) in its α-phase is among the most desirable perovskite compositions for solar cells. However, because of its transition into the yellow δ-phase at room temperature, it is a challenge to process it in ambient air by scalable fabrication methods. Here the introduction of a trace amount of cadmium (in the form of CdI2) to FAPbI3 is reported and found that it enhances the stability of the perovskite's black α-phase polymorph, inhibits non-radiative recombination events, leads to pin-hole free compact surface morphology, and improves band energy alignment. The 0.6% Cd-doped FAPbI3 solar cells show a champion efficiency of 22.7% for 0.049 cm2 and 16.4% for cm2-scale pixels, which, to the best of the knowledge, are among the highest for air-ambient fully blade-coated pure FAPbI3 solar cells with an n-i-p architecture. Transient absorption microscopy measurements reveal that Cd doping reduces the number of trapped charges and increases their lifetimes, promoting charge accumulation and a higher photovoltage. The study sheds light on the potential of cadmium as a homovalent dopant for the stabilization and performance enhancement of FAPbI3 performance solar cells.enAttribution 4.0 InternationalCentre for Advanced Materials and Related Technology (CAMTEC)ArticleDepartment of ChemistryDepartment of Electrical and Computer Engineering