1
|
Seiler H, Zahn D, Taylor VCA, Bodnarchuk MI, Windsor YW, Kovalenko MV, Ernstorfer R. Direct Observation of Ultrafast Lattice Distortions during Exciton-Polaron Formation in Lead Halide Perovskite Nanocrystals. ACS NANO 2023; 17:1979-1988. [PMID: 36651873 PMCID: PMC9933605 DOI: 10.1021/acsnano.2c06727] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 01/10/2023] [Indexed: 05/31/2023]
Abstract
The microscopic origin of slow hot-carrier cooling in lead halide perovskites remains debated and has direct implications for applications. Slow hot-carrier cooling of several picoseconds has been attributed to either polaron formation or a hot-phonon bottleneck effect at high excited carrier densities (>1018 cm-3). These effects cannot be unambiguously disentangled with optical experiments alone. However, they can be distinguished by direct observations of ultrafast lattice dynamics, as these effects are expected to create qualitatively distinct fingerprints. To this end, we employ femtosecond electron diffraction and directly measure the sub-picosecond lattice dynamics of weakly confined CsPbBr3 nanocrystals following above-gap photoexcitation. While we do not observe signatures of a hot-phonon bottleneck lasting several picoseconds, the data reveal a light-induced structural distortion appearing on a time scale varying between 380 and 1200 fs depending on the excitation fluence. We attribute these dynamics to the effect of exciton-polarons on the lattice and the slower dynamics at high fluences to slower sub-picosecond hot-carrier cooling, which slows down the establishment of the exciton-polaron population. Further analysis and simulations show that the distortion is consistent with motions of the [PbBr3]- octahedral ionic cage, and closest agreement with the data is obtained for Pb-Br bond lengthening. Our work demonstrates how direct studies of lattice dynamics on the sub-picosecond time scale can discriminate between competing scenarios proposed in the literature to explain the origin of slow hot-carrier cooling in lead halide perovskites.
Collapse
Affiliation(s)
- Hélène Seiler
- Fritz
Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
- Physics
Department, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Daniela Zahn
- Fritz
Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Victoria C. A. Taylor
- Fritz
Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Maryna I. Bodnarchuk
- Laboratory
for Thin Films and Photovoltaics, Swiss
Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - Yoav William Windsor
- Fritz
Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
- Institut
für Optik und Atomare Physik, Technische
Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Maksym V. Kovalenko
- Laboratory
for Thin Films and Photovoltaics, Swiss
Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Ralph Ernstorfer
- Fritz
Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
- Institut
für Optik und Atomare Physik, Technische
Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| |
Collapse
|
2
|
Cannelli O, Colonna N, Puppin M, Rossi TC, Kinschel D, Leroy LMD, Löffler J, Budarz JM, March AM, Doumy G, Al Haddad A, Tu MF, Kumagai Y, Walko D, Smolentsev G, Krieg F, Boehme SC, Kovalenko MV, Chergui M, Mancini GF. Quantifying Photoinduced Polaronic Distortions in Inorganic Lead Halide Perovskite Nanocrystals. J Am Chem Soc 2021; 143:9048-9059. [PMID: 34075753 PMCID: PMC8227469 DOI: 10.1021/jacs.1c02403] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Indexed: 12/17/2022]
Abstract
The development of next-generation perovskite-based optoelectronic devices relies critically on the understanding of the interaction between charge carriers and the polar lattice in out-of-equilibrium conditions. While it has become increasingly evident for CsPbBr3 perovskites that the Pb-Br framework flexibility plays a key role in their light-activated functionality, the corresponding local structural rearrangement has not yet been unambiguously identified. In this work, we demonstrate that the photoinduced lattice changes in the system are due to a specific polaronic distortion, associated with the activation of a longitudinal optical phonon mode at 18 meV by electron-phonon coupling, and we quantify the associated structural changes with atomic-level precision. Key to this achievement is the combination of time-resolved and temperature-dependent studies at Br K and Pb L3 X-ray absorption edges with refined ab initio simulations, which fully account for the screened core-hole final state effects on the X-ray absorption spectra. From the temporal kinetics, we show that carrier recombination reversibly unlocks the structural deformation at both Br and Pb sites. The comparison with the temperature-dependent XAS results rules out thermal effects as the primary source of distortion of the Pb-Br bonding motif during photoexcitation. Our work provides a comprehensive description of the CsPbBr3 perovskites' photophysics, offering novel insights on the light-induced response of the system and its exceptional optoelectronic properties.
Collapse
Affiliation(s)
- Oliviero Cannelli
- Laboratory
of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast
Science (LACUS), École Polytechnique
Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Nicola Colonna
- Laboratory
for Neutron Scattering and Imaging, Paul
Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
- National
Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale
de Lausanne, CH-1015 Lausanne, Switzerland
| | - Michele Puppin
- Laboratory
of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast
Science (LACUS), École Polytechnique
Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Thomas C. Rossi
- Laboratory
of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast
Science (LACUS), École Polytechnique
Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Dominik Kinschel
- Laboratory
of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast
Science (LACUS), École Polytechnique
Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Ludmila M. D. Leroy
- Laboratory
of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast
Science (LACUS), École Polytechnique
Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- LabCri, Universidade Federal de Minas Gerais, 31270-901 Belo
Horizonte, Brazil
| | - Janina Löffler
- Laboratory
of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast
Science (LACUS), École Polytechnique
Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - James M. Budarz
- Laboratory
of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast
Science (LACUS), École Polytechnique
Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Anne Marie March
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United
States
| | - Gilles Doumy
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United
States
| | - Andre Al Haddad
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United
States
| | - Ming-Feng Tu
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United
States
| | - Yoshiaki Kumagai
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United
States
| | - Donald Walko
- Advanced
Photon Source, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | | | - Franziska Krieg
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, CH-8093 Zürich, Switzerland
- Laboratory
for Thin Films and Photovoltaics, Empa-Swiss
Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Simon C. Boehme
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, CH-8093 Zürich, Switzerland
- Laboratory
for Thin Films and Photovoltaics, Empa-Swiss
Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Maksym V. Kovalenko
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, CH-8093 Zürich, Switzerland
- Laboratory
for Thin Films and Photovoltaics, Empa-Swiss
Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Majed Chergui
- Laboratory
of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast
Science (LACUS), École Polytechnique
Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Giulia F. Mancini
- Laboratory
of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast
Science (LACUS), École Polytechnique
Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| |
Collapse
|