Publications by authors named "M Dyksik"
Luminescence (nano)thermometry has exploded in popularity, offering a remote detection way to measure temperature across diverse fields like nanomedicine, microelectronics, catalysis, and plasmonics. A key advantage is its supposed immunity to strong electromagnetic fields, a crucial feature in many environments. However, this assumption lacks comprehensive experimental verification as most of the proposed luminescent thermometers rely on magnetic ions, such as lanthanides.
View Article and Find Full Text PDFIn 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.
Article Synopsis
- The optical response of 2D layered perovskites features closely spaced spectral signatures, interpreted as phonon replicas, with an energy separation ranging from 12 to 40 meV, depending on the material.
- These materials also show a strong scattering response in resonant Raman spectroscopy above roughly 200 cm (or 25 meV), which is linked to the presence of polarons, exhibiting a distinctive spectral pattern deviating from the Rayleigh line.
- A significant Huang-Rhys factor (S > 6) suggests strong coupling between charge carriers and the lattice, with polaron binding energies between 20-35 meV, influencing the optical properties critical for future opto-electronic applications.
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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