Publications by authors named "A L Efros"
Article Synopsis
- Semiconductor nanoplatelets are unique nanocrystals that emit light with high purity at specific wavelengths determined by their thickness.
- Current challenges in enhancing their light emission sharpness are linked to inconsistencies in the ligand layer on their surface, affecting the localization of excitons and resulting in unwanted scattering.
- By improving the uniformity of the ligand layer, researchers can optimize light emission from nanoplatelets, making them more effective for future optical technologies.
Article Synopsis
- Semiconductor nanocrystals, while useful for light-emitting devices, struggle with the "dark exciton" issue, where they emit less light due to an inactive electronic state.
- A new theoretical mechanism called the Rashba effect can potentially invert the electronic levels, promoting a bright excitonic state, but there's no method to identify suitable materials yet.
- The researchers created a systematic approach to screen over 500,000 solids, narrowing it down to 28 candidates, and found that four of them produce bright ground-state excitons, paving the way for future studies into these promising nanomaterials.
Exciton-polaritons confined in plasmonic cavities are hybridized light-matter quasiparticles, with distinct optical characteristics compared to plasmons and excitons alone. Here, we demonstrate the electric tunability of a single polaritonic quantum dot operating at room temperature in electric-field tip-enhanced strong coupling spectroscopy. For a single quantum dot in the nanoplasmonic tip cavity with variable dc local electric field, we dynamically control the Rabi frequency with the corresponding polariton emission, crossing weak to strong coupling.
View Article and Find Full Text PDFThe brightness of an emitter is ultimately described by Fermi's golden rule, with a radiative rate proportional to its oscillator strength times the local density of photonic states. As the oscillator strength is an intrinsic material property, the quest for ever brighter emission has relied on the local density of photonic states engineering, using dielectric or plasmonic resonators. By contrast, a much less explored avenue is to boost the oscillator strength, and hence the emission rate, using a collective behaviour termed superradiance.
View Article and Find Full Text PDFWe investigate theoretically the band transport of electrons and holes in a "quantum-dot-in-perovskite" solid, a periodic array of semiconductor nanocrystal quantum dots embedded in a matrix of lead halide perovskite. For concreteness we focus on PbS quantum dots passivated by inorganic halogen ligands and embedded in a matrix of CsPbI. We find that the halogen ligands play a decisive role in determining the band offset between the dot and matrix and may therefore provide a straightforward way to control transport experimentally.
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