Trap passivation and suppressed electrochemical dynamics in perovskite solar cells with C60 interlayers
article
In 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.
TNO Identifier
977091
ISSN
00134686
Source
Electrochimica Acta, 433
Publisher
Elsevier Ltd
Article nr.
141215
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