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Title: The formation of CdS quantum dots and Au nanoparticles

Abstract

Abstract We report on microsecond-resolved in-situ SAXS experiments of the early nucleation and growth behavior of both cadmium sulfide (CdS) quantum dots in aqueous solution including the temperature dependence and of gold (Au) nanoparticles. A novel free-jet setup was developped to access reaction times as early as 20 μs. As the signal in particular in the beginning of the reaction is weak the containment-free nature of this sample environment prooved crucial. The SAXS data reveal a two-step pathway with a surprising stability of a structurally relaxed cluster with a diameter of about 2 nm. While these develop rapidly by ionic assembly, a further slower growth is attributed to cluster attachment. WAXS diffraction confirms, that the particles at this early stage are not yet crystalline. This growth mode is confirmed for a temperature range from 25°C to 45°C. An energy barrier for the diffusion of primary clusters in water of 0.60 eV was experimentally observed in agreement with molecular simulations. To access reaction times beyond 100 ms, a stopped-drop setup -again contaiment- free is introduced. SAXS experiments on the growth of Au nanoparticles on an extended time scale provide a much slower growth with one population only. Further, the influence ofmore » ionizing X-ray radiation on the Au particle fromation and growth is discussed.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
German Research Foundation (DFG); USDOE Office of Science - Office of Basic Energy Sciences - Scientific User Facilities Division
OSTI Identifier:
1427543
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Zeitschrift fuer Kristallographie. Crystalline Materials
Additional Journal Information:
Journal Volume: 232; Journal Issue: 1-3; Journal ID: ISSN 2194-4946
Publisher:
de Gruyter
Country of Publication:
United States
Language:
English
Subject:
Au nanoparticles; CdS quantum dots; containment-free; in-situ SAXS; nucleation and growth

Citation Formats

Schiener, Andreas, Schmidt, Ella, Bergmann, Christoph, Seifert, Soenke, Zahn, Dirk, Krach, Alexander, Weihrich, Richard, and Magerl, Andreas. The formation of CdS quantum dots and Au nanoparticles. United States: N. p., 2017. Web. doi:10.1515/zkri-2016-1978.
Schiener, Andreas, Schmidt, Ella, Bergmann, Christoph, Seifert, Soenke, Zahn, Dirk, Krach, Alexander, Weihrich, Richard, & Magerl, Andreas. The formation of CdS quantum dots and Au nanoparticles. United States. doi:10.1515/zkri-2016-1978.
Schiener, Andreas, Schmidt, Ella, Bergmann, Christoph, Seifert, Soenke, Zahn, Dirk, Krach, Alexander, Weihrich, Richard, and Magerl, Andreas. Sun . "The formation of CdS quantum dots and Au nanoparticles". United States. doi:10.1515/zkri-2016-1978.
@article{osti_1427543,
title = {The formation of CdS quantum dots and Au nanoparticles},
author = {Schiener, Andreas and Schmidt, Ella and Bergmann, Christoph and Seifert, Soenke and Zahn, Dirk and Krach, Alexander and Weihrich, Richard and Magerl, Andreas},
abstractNote = {Abstract We report on microsecond-resolved in-situ SAXS experiments of the early nucleation and growth behavior of both cadmium sulfide (CdS) quantum dots in aqueous solution including the temperature dependence and of gold (Au) nanoparticles. A novel free-jet setup was developped to access reaction times as early as 20 μs. As the signal in particular in the beginning of the reaction is weak the containment-free nature of this sample environment prooved crucial. The SAXS data reveal a two-step pathway with a surprising stability of a structurally relaxed cluster with a diameter of about 2 nm. While these develop rapidly by ionic assembly, a further slower growth is attributed to cluster attachment. WAXS diffraction confirms, that the particles at this early stage are not yet crystalline. This growth mode is confirmed for a temperature range from 25°C to 45°C. An energy barrier for the diffusion of primary clusters in water of 0.60 eV was experimentally observed in agreement with molecular simulations. To access reaction times beyond 100 ms, a stopped-drop setup -again contaiment- free is introduced. SAXS experiments on the growth of Au nanoparticles on an extended time scale provide a much slower growth with one population only. Further, the influence of ionizing X-ray radiation on the Au particle fromation and growth is discussed.},
doi = {10.1515/zkri-2016-1978},
journal = {Zeitschrift fuer Kristallographie. Crystalline Materials},
issn = {2194-4946},
number = 1-3,
volume = 232,
place = {United States},
year = {2017},
month = {1}
}