Gratia, Paul Grancini, Giulia Audinot, Jean-Nicolas Jeanbourquin, Xavier Mosconi, Edoardo Zimmermann, Iwan Dowsett, David Lee, Yonghui Grätzel, Michael Angelis, Filippo De Sivula, Kevin Wirtz, Tom Nazeeruddin, Mohammad Khaja Intrinsic Halide Segregation at Nanometer Scale Determines the High Efficiency of Mixed Cation/Mixed Halide Perovskite Solar Cells Compositional engineering of a mixed cation/mixed halide perovskite in the form of (FAPbI<sub>3</sub>)<sub>0.85</sub>(MAPbBr<sub>3</sub>)<sub>0.15</sub> is one of the most effective strategies to obtain record-efficiency perovskite solar cells. However, the perovskite self-organization upon crystallization and the final elemental distribution, which are paramount for device optimization, are still poorly understood. Here we map the nanoscale charge carrier and elemental distribution of mixed perovskite films yielding 20% efficient devices. Combining a novel in-house-developed high-resolution helium ion microscope coupled with a secondary ion mass spectrometer (HIM-SIMS) with Kelvin probe force microscopy (KPFM), we demonstrate that part of the mixed perovskite film intrinsically segregates into iodide-rich perovskite nanodomains on a length scale of up to a few hundred nanometers. Thus, the homogeneity of the film is disrupted, leading to a variation in the optical properties at the micrometer scale. Our results provide unprecedented understanding of the nanoscale perovskite composition. device optimization;record-efficiency perovskite;Intrinsic Halide Segregation;iodide-rich perovskite nanodomains;High Efficiency;MAPbBr 3;perovskite films;Kelvin probe force microscopy;ion mass spectrometer;nanoscale charge carrier;perovskite self-organization;nanoscale perovskite composition;micrometer scale;FAPbI 3;helium ion microscope;perovskite film;novel in-house-developed;length scale;HIM-SIMS;Nanometer Scale Determines;KPFM 2016-11-29
    https://acs.figshare.com/articles/journal_contribution/Intrinsic_Halide_Segregation_at_Nanometer_Scale_Determines_the_High_Efficiency_of_Mixed_Cation_Mixed_Halide_Perovskite_Solar_Cells/4282592
10.1021/jacs.6b10049.s001