TulusMuscarella, Loreta A.Loreta A.MuscarellaYULIA GALAGANBoehme, Simon ChristianSimon ChristianBoehmevon Hauff, ElizabethElizabethvon Hauff2023-06-202023-06-202022-11-2000134686https://scholars.lib.ntu.edu.tw/handle/123456789/632994In this study, we quantify the impact of C60-passivation layers in Cs0.15FA0.85PbI2.75Br0.25 double-cation perovskite solar cells. We apply a combination of impedance spectroscopy, photoluminescence (PL) spectroscopy, and X-ray diffraction (XRD) to identify the origin for the increase in power conversion efficiencies and operational stability for solar cells fabricated with C60/ZnO electron transport layer (ETL) versus reference cells with a ZnO ETL. XRD reveals an increase in PbI2 while PL spectroscopy reveals an increase in Br-rich regions in the perovskite bulk in devices containing C60 interlayers. We apply impedance spectroscopy to quantify the electrochemical dynamics in both solar cell architectures. Solar cells with C60/ZnO ETL demonstrate less pronounced and slower electrochemical dynamics in the impedance spectra than solar cells with ZnO ETL. We conclude that C60 leads to the formation of PbI2-rich and Br-rich domains in the perovskite absorber layer, resulting in reduced recombination losses and improved operational stability.C 60 | Equivalent circuit model | Impedance spectroscopy | Perovskite | Solar cell | Transport layer | ZnO[SDGs]SDG7journal article10.1016/j.electacta.2022.1412152-s2.0-85138465949WOS:000866553600004https://api.elsevier.com/content/abstract/scopus_id/85138465949