TY  - GEN
A1  - Liebig, Ferenc
A1  - Henning, Ricky
A1  - Sarhan, Radwan Mohamed
A1  - Prietzel, Claudia Christina
A1  - Schmitt, Clemens Nikolaus Zeno
A1  - Bargheer, Matias
A1  - Koetz, Joachim
T1  - A simple one-step procedure to synthesise gold nanostars in concentrated aqueous surfactant solutions
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - Due to the enhanced electromagnetic field at the tips of metal nanoparticles, the spiked structure of gold nanostars (AuNSs) is promising for surface-enhanced Raman scattering (SERS). Therefore, the challenge is the synthesis of well designed particles with sharp tips. The influence of different surfactants, i.e., dioctyl sodium sulfosuccinate (AOT), sodium dodecyl sulfate (SDS), and benzylhexadecyldimethylammonium chloride (BDAC), as well as the combination of surfactant mixtures on the formation of nanostars in the presence of Ag⁺ ions and ascorbic acid was investigated. By varying the amount of BDAC in mixed micelles the core/spike-shell morphology of the resulting AuNSs can be tuned from small cores to large ones with sharp and large spikes. The concomitant red-shift in the absorption toward the NIR region without losing the SERS enhancement enables their use for biological applications and for time-resolved spectroscopic studies of chemical reactions, which require a permanent supply with a fresh and homogeneous solution. HRTEM micrographs and energy-dispersive X-ray (EDX) experiments allow us to verify the mechanism of nanostar formation according to the silver underpotential deposition on the spike surface in combination with micelle adsorption.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 769 
KW  - optical-properties
KW  - nanoparticles
KW  - sers
KW  - ultrafast
KW  - size
KW  - nanotriangles
KW  - nanoflowers
KW  - wavelength
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-438743
SN  - 1866-8372
IS  - 769
SP  - 23633
EP  - 23641
ER  - 
TY  - GEN
A1  - Liebig, Ferenc
A1  - Sarhan, Radwan Mohamed
A1  - Prietzel, Claudia Christina
A1  - Reinecke, Antje
A1  - Koetz, Joachim
T1  - “Green” gold nanotriangles: synthesis, purification by polyelectrolyte/micelle depletion flocculation and performance in surface-enhanced Raman scattering
N2  - The aim of this study was to develop a one-step synthesis of gold nanotriangles (NTs) in the presence of mixed phospholipid vesicles followed by a separation process to isolate purified NTs. Negatively charged vesicles containing AOT and phospholipids, in the absence and presence of additional reducing agents (polyampholytes, polyanions or low molecular weight compounds), were used as a template phase to form anisotropic gold nanoparticles. Upon addition of the gold chloride solution, the nucleation process is initiated and both types of particles, i.e., isotropic spherical and anisotropic gold nanotriangles, are formed simultaneously. As it was not possible to produce monodisperse nanotriangles with such a one-step procedure, the anisotropic nanoparticles needed to be separated from the spherical ones. Therefore, a new type of separation procedure using combined polyelectrolyte/micelle depletion flocculation was successfully applied. As a result of the different purification steps, a green colored aqueous dispersion was obtained containing highly purified, well-defined negatively charged flat nanocrystals with a platelet thickness of 10 nm and an edge length of about 175 nm. The NTs produce promising results in surface-enhanced Raman scattering.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 317 
KW  - morphological transformation
KW  - halide-ions
KW  - nanoparticles
KW  - shape
KW  - size
KW  - nanoprisms
KW  - vesicles
KW  - nanorods
KW  - silver
KW  - poly(ethyleneimine)
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-394430
SP  - 33561
EP  - 33568
ER  -