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Excited-state vibrational dynamics toward the polaron in methylammonium lead iodide perovskite
- Source :
- Nature communications, vol 9, iss 1, Nature Communications, Nature Communications, Vol 9, Iss 1, Pp 1-9 (2018), Park, M; Neukirch, AJ; Reyes-Lillo, SE; Lai, M; Ellis, SR; Dietze, D; et al.(2018). Excited-state vibrational dynamics toward the polaron in methylammonium lead iodide perovskite. Nature Communications, 9(1). doi: 10.1038/s41467-018-04946-7. UC Berkeley: Retrieved from: http://www.escholarship.org/uc/item/2qn8d4x8
- Publication Year :
- 2018
- Publisher :
- Springer Science and Business Media LLC, 2018.
-
Abstract
- Hybrid organic–inorganic perovskites have attractive optoelectronic properties including exceptional solar cell performance. The improved properties of perovskites have been attributed to polaronic effects involving stabilization of localized charge character by structural deformations and polarizations. Here we examine the Pb–I structural dynamics leading to polaron formation in methylammonium lead iodide perovskite by transient absorption, time-domain Raman spectroscopy, and density functional theory. Methylammonium lead iodide perovskite exhibits excited-state coherent nuclear wave packets oscillating at ~20, ~43, and ~75 cm−1 which involve skeletal bending, in-plane bending, and c-axis stretching of the I–Pb–I bonds, respectively. The amplitudes of these wave packet motions report on the magnitude of the excited-state structural changes, in particular, the formation of a bent and elongated octahedral PbI64− geometry. We have predicted the excited-state geometry and structural changes between the neutral and polaron states using a normal-mode projection method, which supports and rationalizes the experimental results. This study reveals the polaron formation via nuclear dynamics that may be important for efficient charge separation.<br />Elucidating electron-phonon coupling in hybrid organic-inorganic perovskites may help us to understand the high photovoltaic efficiency. Here, the authors observe low-frequency Raman modes and related nuclear displacements of the Pb–I framework, indicating how these vibrational motions lead to polaron formation in perovskites.
- Subjects :
- Materials science
Science
Wave packet
Iodide
General Physics and Astronomy
02 engineering and technology
Perovskite
010402 general chemistry
Polaron
01 natural sciences
Article
General Biochemistry, Genetics and Molecular Biology
symbols.namesake
Ultrafast laser spectroscopy
Perovskite (structure)
chemistry.chemical_classification
Multidisciplinary
General Chemistry
021001 nanoscience & nanotechnology
0104 chemical sciences
Lead
chemistry
Chemical physics
Excited state
Methylammonium
symbols
Condensed Matter::Strongly Correlated Electrons
Density functional theory
0210 nano-technology
Raman spectroscopy
Subjects
Details
- ISSN :
- 20411723
- Volume :
- 9
- Database :
- OpenAIRE
- Journal :
- Nature Communications
- Accession number :
- edsair.doi.dedup.....367b2cb84f3ed91fd3e61e348751faec