| Autor: |
Tim Fürmann, Jochen Feldmann, Sebastian Rieger, Jacek K. Stolarczyk |
| Rok vydání: |
2022 |
| Předmět: |
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| Zdroj: |
Ultrafast Phenomena and Nanophotonics XXVI. |
| Popis: |
Bismuth oxyiodide (BiOI) is a promising material for photocatalysis combining intriguing optical and structural properties. We show that excitation by a femtosecond laser pulse creates coherent phonons inducing a time-variant oscillating modulation of the optical density. We find that the two underlying frequencies originate from lattice vibrations along the [001] crystallographic axis, the stacking direction of oppositely charged layers in BiOI. This is consistent with a subpicosecond charge separation driven by a built-in dipolar field. This partially screens the field, launching coherent phonons. Further, we determine the two major dephasing mechanisms that lead to the loss of vibronic coherence: (i) the anharmonic decay of an optical phonon into two acoustic phonons and (ii) phonon-carrier scattering. Our results provide a direct demonstration of the presence of an electric field in BiOI along the [001] axis and show its role in efficient charge separation that is crucial for photocatalytic applications of BiOI. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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