A Combined SAXS/SANS Study for the in Situ Characterization of Ligand Shells on Small Nanoparticles: The Case of XXXX .

@entity35455 @entity1948 @entity598
UNASSIGNED: @entity1948 nanoparticles (NPs) have great potential for their use in, e.g., thin film solar cells due to their electro-optical properties adjustable on the nanoscale. Therefore, the production of well-defined NPs is of major interest. For a targeted production process, the knowledge of the stabilization layer of the NPs during and after their formation is of particular importance. For the study of the stabilizer layer of @entity1948 NPs prepared in a wet chemical synthesis from @entity35455 , only ex situ studies have been performed so far. An @entity598 layer bound to the surface of the dried NPs was found; however, an in situ study which addresses the stabilizing layer surrounding the NPs in a native dispersion was missing. By the combination of small angle scattering with neutrons and X-rays (SANS and SAXS) for the same sample, we are now able to observe the @entity598 shell in situ for the first time. In addition, the changes of this shell could be followed during the ripening process for different temperatures. With increasing size of the @entity1948 core (dcore) the surrounding shell (dshell) becomes larger, and the @entity598 concentration within the shell is reduced. For all samples, the shell thickness was found to be larger than the maximum extension of an @entity598 molecule with @entity598 concentrations within the shell below 50 vol %. Thus, there is not a monolayer of @entity598 molecules that covers the NPs but rather a swollen shell of @entity598 ions. This shell is assumed to hinder the growth of the NPs to larger macrostructures. In addition, we found that the partition coefficient   between @entity598 in the shell surrounding the NPs and the total amount of @entity598 in the solution is about 10% which is in good agreement with ex situ data determined by thermogravimetric analysis.
