@article{9ae545221aa545f4a4c251108faeefb1,
title = "Halogen Redox Shuttle Explains Voltage-Induced Halide Redistribution in Mixed-Halide Perovskite Devices",
abstract = "Voltage-induced halide segregation greatly limits the optoelectronic applications of mixed-halide perovskite devices, but a mechanistic explanation behind this phenomenon remains unclear. In this work, we use electron microscopy and elemental mapping to directly measure the halide redistribution in mixed-halide perovskite solar cells with quasi-ion-impermeable contact layers under different bias polarities to find iodide and bromide accumulation at the cathode and anode, respectively. This is consistent with a mechanism based on preferential iodide oxidation at the anode, leading to unbalanced Ii+, IX-, and BrX- fluxes. Importantly, switching the anode from {"}inert{"}Au to {"}active{"}Ag prevents segregation because Ag oxidation precludes the oxidation of lattice iodide, which suggests employing redox-active additives as a general strategy to suppress halide segregation. Overall, these results show that halide perovskite devices operate as solid-state electrochemical cells when threshold voltages are exceeded, providing fresh insight to understand the impacts of voltage bias on halide perovskite devices.",
author = "Zhaojian Xu and Kerner, {Ross A.} and Harvey, {Steven P.} and Kai Zhu and Berry, {Joseph J.} and Rand, {Barry P.}",
note = "Funding Information: We acknowledge funding for this work by the Department of the Navy, Office of Naval Research, under ONR award number N00014-21-1-2767. This work was authored in part by the National Renewable Energy Laboratory, operated by the Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding for R.A.K., S.P.H, K.Z., and J.J.B. was provided by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy, Solar Energy Technologies Office (SETO) project “Advanced Perovskite Cells and Modules” program (DE-FOA-0000990). The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. The authors acknowledge the use of Princeton{\textquoteright}s Imaging and Analysis Center (IAC), which is partially supported by the Princeton Center for Complex Materials (PCCM), a National Science Foundation (NSF) Materials Research Science and Engineering Center (MRSEC; DMR-2011750). Publisher Copyright: {\textcopyright} 2022 American Chemical Society.",
year = "2022",
doi = "10.1021/acsenergylett.2c02385",
language = "English (US)",
pages = "513--520",
journal = "ACS Energy Letters",
issn = "2380-8195",
publisher = "American Chemical Society",
}