Publications by authors named "A Surrente"
In metal halide perovskites, the complex dielectric screening together with low energy of phonon modes leads to non-negligible Fröhlich coupling. While this feature of perovskites has already been used to explain some of the puzzling aspects of carrier transport in these materials, the possible impact of polaronic effects on the optical response, especially excitonic properties, is much less explored. Here, with the use of magneto-optical spectroscopy, we revealed the non-hydrogenic character of the excitons in metal halide perovskites, resulting from the pronounced Fröhlich coupling.
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- The optical behavior of 2D perovskites relies heavily on excitons, which can be manipulated by altering the thickness of the perovskite layers.
- Researchers studied the exciton fine structure in a specific 2D perovskite by varying the number of inorganic layers from 1 to 4.
- Their findings reveal splitting of excitonic states across different confinement levels and show how the optical properties transition from 2D to 3D as the layer thickness increases.
Stacking monolayers of transition metal dichalcogenides (TMDs) has led to the discovery of a plethora of new exotic phenomena, resulting from moiré pattern formation. Due to the atomic thickness and high surface-to-volume ratio of heterostructures, the interfaces play a crucial role. Fluctuations in the interlayer distance affect interlayer coupling and moiré effects.
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- - Two-dimensional van der Waals materials, like Ruddlesden-Popper perovskites, exhibit strong excitonic effects due to their unique structural features, making them ideal for studying exciton physics.
- - Using polarization-resolved optical spectroscopy, researchers observed tightly bound excitons and strong exciton-phonon coupling in (PEA)2PbI4, revealing exciton fine structure splitting in phonon-assisted transitions.
- - The study found that the splitting of phonon-assisted transitions differs from the zero-phonon lines, attributed to the unique symmetry of (PEA)2PbI4's lattice and the selective coupling of exciton states to phonon modes.
The optimized exploitation of perovskite nanocrystals and nanoplatelets as highly efficient light sources requires a detailed understanding of the energy spacing within the exciton manifold. Dark exciton states are particularly relevant because they represent a channel that reduces radiative efficiency. Here, we apply large in-plane magnetic fields to brighten optically inactive states of CsPbBr-based nanoplatelets for the first time.
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