Topic
Exciton
About: Exciton is a research topic. Over the lifetime, 31603 publications have been published within this topic receiving 810642 citations.
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TL;DR: In this article, an anatase thin films were fabricated on lattice-matched (−0.2%) LaAlO3 (001) substrates by laser molecular-beam epitaxy.
Abstract: Epitaxial anatase thin films were fabricated on lattice-matched (−0.2%) LaAlO3 (001) substrates in the layer-by-layer fashion by laser molecular-beam epitaxy. X-ray diffraction and transmission electron microscope show the films to exhibit high crystallinity and atomically defined interfaces. By virtue of the adoption of LaAlO3 substrate, which is transparent to photoexcitation of TiO2, optical band gaps could be determined to be 3.3 eV at room temperature. A photoluminescence band due to recombination of self-trapped excitons was observed at 5 K to give the peak maximum at 2.2 eV. As a result of the high degree of orientation of the epitaxial films, anisotropic optical absorption was clearly observed.
154 citations
TL;DR: It is found that the exciton diffusion length, which exceeds 30 nm in some cases, can be tuned by adjusting the inorganic shell thickness and organic ligand length, offering a powerful strategy for controlling exciton movement.
Abstract: Colloidal quantum dots (QDs) are promising materials for use in solar cells, light-emitting diodes, lasers, and photodetectors, but the mechanism and length of exciton transport in QD materials is not well understood. We use time-resolved optical microscopy to spatially visualize exciton transport in CdSe/ZnCdS core/shell QD assemblies. We find that the exciton diffusion length, which exceeds 30 nm in some cases, can be tuned by adjusting the inorganic shell thickness and organic ligand length, offering a powerful strategy for controlling exciton movement. Moreover, we show experimentally and through kinetic Monte Carlo simulations that exciton diffusion in QD solids does not occur by a random-walk process; instead, energetic disorder within the inhomogeneously broadened ensemble causes the exciton diffusivity to decrease over time. These findings reveal new insights into exciton dynamics in disordered systems and demonstrate the flexibility of QD materials for photonic and optoelectronic applications.
154 citations
TL;DR: An overview of the current state-of-the-art of quantum confinement effects in perovskite nanocrystals is provided, with a focus on synthetic strategies and resulting optical properties, characterization methods, and emerging applications.
Abstract: Metal halide perovskites have emerged as a promising new class of layered semiconductor material for light-emitting and photovoltaic applications owing to their outstanding optical and optoelectronic properties. In nanocrystalline form, these layered perovskites exhibit extremely high photoluminescence quantum yields (PLQYs) and show quantum confinement effects analogous to conventional semiconductors when their dimensions are reduced to sizes comparable to their respective exciton Bohr radii. The reduction in size leads to strongly blueshifted photoluminescence and large exciton binding energies up to several hundreds of meV. This not only makes them interesting for optoelectronic devices, but also enables complex architectures based on cascaded energy transfer. Here, an overview of the current state-of-the-art of quantum confinement effects in perovskite nanocrystals is provided, with a focus on synthetic strategies and resulting optical properties, characterization methods, and emerging applications.
154 citations
IBM1
154 citations
TL;DR: This CD effect appears to be a sensitive probe to study changes in protein mobility and in protein-protein interactions and is suggested that DMSO increases the protein mobility in the membrane.
154 citations