Dresden 2017 – scientific programme

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O: Fachverband Oberflächenphysik

O 52: Nanostructures at Surfaces: Dots, Particles, Clusters

O 52.11: Poster

Tuesday, March 21, 2017, 18:30–20:30, P1C

Characterization of Ag clusters in ionic liquids with DLS — •Florian Lippert, Stefanie Roese, and Heinz Hövel — Fakultät Physik / DELTA, TU Dortmund, Otto-Hahn-Str. 4, 44221 Dortmund

Ag clusters produced in a supersonic expansion [1] can be deposited without coalescence into room temperature ionic liquids (RTILs), which are salts of weakly coordinating cations and anions being liquid at room temperature controlled by UV/Vis spectroscopy [2].

To get an insight into the process of stabilization and aggregation, we investigate Ag clusters in EMIM-FAP and BMIM-PF₆ by dynamic light scattering (DLS) [3].

The time-dependent change of the scattered light intensity depends on the Brownian motion of the nanoparticles. By means of that it is possible to receive the size distribution of the particles given by their hydrodynamic radius.

For proper measurement the material properties as viscosity and refractive index are indispensable. To determine the refractive index of the RTIL an Abbe refractometer and extrapolation to other wavelengths is used.

Measurements for storage at different temperatures show how stable the clusters in the ionic liquid are over time scales of several days.

[1] H. Hövel, S. Fritz, A. Hilger, U. Kreibig and M. Vollmer, Phys. Rev. B 48, 18178, 1993 [2] D. Engemann, S. Roese and H. Hövel, J. Phys. Chem. C 120, 6239, 2016 [3] B.J. Berne and R. Pecora, Dynamic Light Scattering, Dover Publications, New York, 2000