Role of the ligand layer for photoluminescence spectral diffusion of CdSe/ZnS nanoparticles

The time-resolved photoluminescence (PL) characteristics of single CdSe/ZnS nanoparticles, embedded in a poly(methyl methacrylate) layer, is studied at room temperature. We observe a strong spectral jitter of up to 55 meV, which is correlated with a change in the observed linewidth. We evaluate this...

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Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2013-09, Vol.88 (12), Article 125302
Main Authors: Braam, Daniel, Mölleken, Andreas, Prinz, Günther M., Notthoff, Christian, Geller, Martin, Lorke, Axel
Format: Article
Language:English
Subjects:
Cadmium selenides
Charge
Correlation
Diffusion
Intermetallics
Jitter
Nanoparticles
Spectra
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Summary:The time-resolved photoluminescence (PL) characteristics of single CdSe/ZnS nanoparticles, embedded in a poly(methyl methacrylate) layer, is studied at room temperature. We observe a strong spectral jitter of up to 55 meV, which is correlated with a change in the observed linewidth. We evaluate this correlation effect using a simple model, based on the quantum confined Stark effect induced by a diffusing charge in the vicinity of the nanoparticle. This allows us to derive a mean distance between the center of the particle and the diffusing charge of approximately 5 nm on average, as well as a mean charge carrier displacement within the integration time. These results are reproducible, even for particles which exhibit strong blueing, with shifts of up to 150 meV. Both the statistics and its independence of core-shell alterations lead us to conclude that the charge causing the spectral jitter is situated in the ligands or on its surface.
ISSN:1098-0121
1550-235X
DOI:10.1103/PhysRevB.88.125302