Direct Observation of Electron–Phonon Coupling and Slow Vibrational Relaxation in Organic–Inorganic Hybrid Perovskites
| Autor: | Julian Gebhardt, Joseph E. Subotnik, Daniel B. Straus, James M. Kikkawa, Cherie R. Kagan, Andrew M. Rappe, Sebastian Hurtado Parra, Natasha Iotov |
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| Rok vydání: | 2016 |
| Předmět: |
Condensed Matter::Quantum Gases
Photoluminescence Condensed matter physics Condensed Matter::Other Chemistry Exciton Binding energy 02 engineering and technology General Chemistry Dielectric Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Biochemistry Molecular physics Catalysis 0104 chemical sciences Condensed Matter::Materials Science Colloid and Surface Chemistry Vibrational energy relaxation 0210 nano-technology Absorption (electromagnetic radiation) Homogeneous broadening Quantum |
| Zdroj: | Journal of the American Chemical Society. 138:13798-13801 |
| ISSN: | 1520-5126 0002-7863 |
| Popis: | Quantum and dielectric confinement effects in Ruddlesden-Popper 2D hybrid perovskites create excitons with a binding energy exceeding 150 meV. We exploit the large exciton binding energy to study exciton and carrier dynamics as well as electron-phonon coupling (EPC) in hybrid perovskites using absorption and photoluminescence (PL) spectroscopies. At temperatures75 K, we resolve splitting of the excitonic absorption and PL into multiple regularly spaced resonances every 40-46 meV, consistent with EPC to phonons located on the organic cation. We also resolve resonances with a 14 meV spacing, in accord with coupling to phonons with mixed organic and inorganic character. These assignments are supported by density-functional theory calculations. Hot exciton PL and time-resolved PL measurements show that vibrational relaxation occurs on a picosecond time scale competitive with that for PL. At temperatures75 K, excitonic absorption and PL exhibit homogeneous broadening. While absorption remains homogeneous, PL becomes inhomogeneous at temperatures75K, which we speculate is caused by the formation and subsequent dynamics of a polaronic exciton. |
| Databáze: | OpenAIRE |
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