Institut für Physikalische Chemie
VG II 145
Phillip Witthöft is working on the in-situ characterization of nanoparticle
growth during the initial steps of reaction by X-ray diffraction
techniques in combination with optical spectroscopy at the same time. With our
Free-Liquid-Jet System he is able to track these reactions by time-resolved
measurements and follow the growth process in the range of milliseconds.
fig. 1: (l) Setup of the Free-Liquid-Jet System which can be
used for time-resolved investigations of ultrafast reactions. Therefor two
precursor solutions were combined in the mixing chamber to start a synthesis reaction.
(r) The setup provides simultaneous measurements of optical spectroscopy and
X-ray diffraction to follow the structural transformation (X-ray) and size
the in-situ syntheses the shape
transformation by melting nanoscopic metal particles via laser-induced heating
is also in the focus of research. Here we are interested in ultrafast imaging
of these shape transformation as well as changes in crystal facets and other
ultrafast reaction (e.g. ion exchange in semiconductor nanoparticles).
fig 2: (l) TEM image of 99x50 nm gold
nanorods following the synthesis by Murray et al. (2013). Aim of the project is
the time-resolved investigation of gold nanorod melting.
melting of gold nanorods: investigating shape transformation and surface changes
with high resolution transmission electron microscopy (HRTEM)
exchange in cadmium selenide nanoparticles with silver ions: reaction tracking
with UV-Vis spectroscopy and energy dispersive X-ray spectroscopy (EDX)
the growth of cadmium selenide nanowires in a Free-Liquid-Jet system: in-situ synthesis and optical
observation of the growth process with UV-Vis spectroscopy and X-ray
project: Executing ligand exchange from CTAB to thiolated PEG for bio
applications in living cells (e.g. hyperthermia by IR-absorption)