@article{b4a73f2338774c968d6dde59f5aa2481,
title = "Ultrafast Imaging of Carrier Cooling in Metal Halide Perovskite Thin Films",
abstract = "Understanding carrier relaxation in lead halide perovskites at the nanoscale is critical for advancing their device physics. Here, we directly image carrier cooling in polycrystalline CH3NH3PbI3 films with nanometer spatial resolution. We observe that upon photon absorption, highly energetic carriers rapidly thermalize with the lattice at different rates across the film. The initial carrier temperatures vary by many multiples of the lattice temperature across hundreds of nanometers, a factor that cannot be accounted for by excess photon energy above the bandgap alone or in variations of the initial carrier density. Electron microscopy suggests that morphology plays a critical role in determining the initial carrier temperature and that carriers in small crystal domains decay slower than those in large crystal domains. Our results demonstrate that local disorder dominates the observed carrier behavior, highlighting the importance of making local rather than averaged measurements in these materials.",
keywords = "Perovskite, carriers, cooling, microscopy, ultrafast",
author = "Sanghee Nah and Spokoyny, {Boris M.} and Soe, {Chan M.M.} and Stoumpos, {Constantinos C.} and Kanatzidis, {Mercouri G.} and Elad Harel",
note = "Funding Information: E.H. acknowledges support by the Air Force Office of Scientific Research (FA9550-14-1-0005), and the Packard Foundation (2013-39272) in part. M.K. acknowledges support by the U.S. Department of Energy, Office of Science, Basic Energy Sciences (DE-SC-0012541, synthesis and physical characterization of samples). The electron microscopy work made use of the EPIC facility of Northwestern University{\textquoteright}s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1121262) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. Funding Information: E.H. acknowledges support by the Air Force Office of Scientific Research (FA9550-14-1-0005), and the Packard Foundation (2013-39272) in part. M.K. acknowledges support by the U.S. Department of Energy, Office of Science, Basic Energy Sciences (DE-SC-0012541, synthesis and physical characterization of samples). The electron microscopy work made use of the EPIC facility of Northwestern University's NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1121262) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN.",
year = "2018",
month = feb,
day = "14",
doi = "10.1021/acs.nanolett.7b04520",
language = "English",
volume = "18",
pages = "1044--1048",
journal = "Nano Letters",
issn = "1530-6984",
publisher = "American Chemical Society",
number = "2",
}