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Abstract Hybrid organic–inorganic perovskites such as methylammonium lead iodide have emerged as promising semiconductors for energy‐relevant applications. The interactions between charge carriers and lattice vibrations, giving rise to polarons, have been invoked to explain some of their extraordinary optoelectronic properties. Here, time‐resolved optical spectroscopy is performed, with off‐resonant pumping and electronic probing, to examine several representative lead iodide perovskites. The temporal oscillations of electronic bandgaps induced by coherent lattice vibrations are reported, which is attributed to antiphase octahedral rotations that dominate in the examined 3D and 2D hybrid perovskites. The off‐resonant pumping scheme permits a simplified observation of changes in the bandgap owing to theAgvibrational mode, which is qualitatively different from vibrational modes of other symmetries and without increased complexity of photogenerated electronic charges. The work demonstrates a strong correlation between the lead–iodide octahedral framework and electronic transitions, and provides further insights into the manipulation of coherent optical phonons and related properties in hybrid perovskites on ultrafast timescales.
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Modulating the electronic properties of perovskite via σ–π interfacial interactions: A computational study
By means of density functional theory computations, we comprehensively investigated the stability and electronic properties of the hybrid CH3NH3PbI3 (methylammonium lead iodide, MAPI)/graphene heterojunctions, where the MAPI layer was adopted with MAI (methylammonium iodide)-terminations. Our computations demonstrated that the σ–π interfacial interactions make the contact very stable, and such interactions lead to charge redistribution and concomitant internal electric field in the interface, which is beneficial for the electron-hole separation.
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- Award ID(s):
- 1736093
- PAR ID:
- 10594959
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- APL Materials
- Volume:
- 6
- Issue:
- 11
- ISSN:
- 2166-532X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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