Size-Dependent Ligand Layer Dynamics in Semiconductor Nanocrystals Probed by Anisotropy Measurements

Colloidal semiconductor nanocrystals (NC) have reached a high level of synthetic control allowing the tuning of their properties, and their use in various applications. However, the surface of NCs and in particular their size‐dependent capping organic ligand behavior, which play an important role in...

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Bibliographic Details
Published in:Angewandte Chemie International Edition 2015-10, Vol.54 (42), p.12463-12467
Main Authors: Hadar, Ido, Abir, Tsafrir, Halivni, Shira, Faust, Adam, Banin, Uri
Format: Article
Language:English
Subjects:
Anisotropy
Colloids
Dyes
Dynamic tests
Dynamics
fluorescence spectroscopy
Ligands
Nanocrystals
Nanoparticles - chemistry
nanotechnology
Particle Size
polarized spectroscopy
Semiconductors
surface chemistry
Surface Properties
Synthesis
Thermodynamics
Tuning
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Summary:Colloidal semiconductor nanocrystals (NC) have reached a high level of synthetic control allowing the tuning of their properties, and their use in various applications. However, the surface of NCs and in particular their size‐dependent capping organic ligand behavior, which play an important role in the NC synthesis, dispersibility, and optoelectronic properties, is still not well understood. We study the size‐dependent properties of the ligand shell on the surface of NCs, by embedding surface bound dyes as a probe within the ligand shell. The reorientation times for these dyes show a linear dependence on the NC surface curvature indicating size‐dependent change in viscosity, which is related to a change in the density of the ligand layer because of the geometry of the surface, a unique feature of NCs. Understanding the properties of the ligand shell will allow rational design of the surface to achieve the desired properties, providing an additional important knob for tuning their functionality. Dynamic properties of a ligand shell: The size‐dependent dynamic properties of an organic ligand shell, capping the surface of colloidal nanocrystals, have been studied by probing polarized emission of surface‐bound organic dyes (see picture). These properties affect the synthesis, dispersibility, and optoelectronic features of colloidal nanocrystals.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201502999