The Langmuir-Blodgett technique was utilized and optimized to produce closed monolayers of cobalt-platinum nanoparticles over vast areas. It is shown that sample preparation, "dipping angle", and subphase type have a strong impact on the quality of the produced films. The amount of ligands on the nanoparticle's surface must be minimized, the dipping angle must be around 105 degrees , while the glycol subphase is necessary to obtain nanoparticle monolayers. The achieved films were characterized by scanning electron microscopy (SEM) and grazing incidence X-ray scattering (GISAXS). The electrical properties of the deposited films were studied by direct current (DC) measurements, showing a discrepancy to the variable range hopping transport from the granular metal model and favoring the simple thermal activated charge transport. SEM, GISAXS, as well as DC measurements confirm a narrow size distribution and high ordering of the deposited films.

Designer jackets: Polydentate amino‐functionalized poly(ethylene oxide)s with various block lengths are synthesized and used for ligand exchange and phase transfer of quantum dots and magnetic nanoparticles (see scheme; TEM images of the particles before and after the exchange are also shown). The ligands enable the transfer of the previously water‐insoluble particles into aqueous media.

The interaction of nitrogen, oxygen, and hydrogen plasmas with spin‐coated arrays of colloidal cobalt–platinum particles was investigated with a large variety of microscopic and spectroscopic techniques. It could be demonstrated that the organic ligands of the nanoparticles can be completely removed. Yet, due to the short (∼1.6 nm) interparticle distances within the layers, strong degradation and sintering effects are observed after hydrogen and nitrogen plasma treatments. In the case of oxygen plasma, the shape and size of the individual particles are unaffected and can be preserved, even if a short hydrogen plasma is subsequently applied to reduce the particles back to their metallic state. Nevertheless, the mesoscopic order of the particle arrays is slightly decreased as observed by the breakup of larger ordered areas into smaller domains forming island–trench structures. Probing the surface chemistry of the particles with temperature programmed desorption, a rather complex surface chemistry is found to result from the plasma treatments. The first TPD spectrum after the cleaning process with oxygen and subsequent hydrogen plasmas reveals that the particles are loaded with adsorbed and implanted hydrogen. After removal of this hydrogen, subsequent TPD spectra using CO as a probe molecule, show broad signals between 190 and 360 K pointing to nonmetallic surface properties. While the platinum was found to be completely reduced, XPS measurements reveal a remaining fraction of oxidic cobalt species which are enriched at the surface. Thus, although the structure of the close‐packed Co–Pt nanoparticle arrays can be qualitatively preserved during plasma‐based ligand removal, the treatment leads to a complex materials system the chemical properties of which are influenced by the particle components, the substrate, and the plasma media.

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A compact, versatile, and simple rf plasma source with capacitive coupling compatible to ultrahigh vacuum (UHV) requirements was designed and built to allow sequences of sample surface modification in plasma and surface preparation and analysis in vacuum without breaking the vacuum. The plasma source was operated at working pressures of less than 1 to a few millibars. Sample transfer to UHV was performed at pressures around 10−9mbar. For easy integration into an existing UHV setup, the sample recipient and transfer system were made to accept standard commercial sample holders. Preliminary experiments were performed by exposing monolayers of colloidal CoPt3 nanoparticles to oxygen and hydrogen plasmas. The structural and chemical effects of the plasma treatments were analyzed with scanning electron microscopy and x-ray photoelectron spectroscopy.