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1.  Purification of ethanol for highly sensitive self-assembly experiments 
Summary
Ethanol is the preferred solvent for the formation of self-assembled monolayers (SAMs) of thiolates on gold. By applying a thin film sensor system, we could demonstrate that even the best commercial qualities of ethanol contain surface-active contaminants, which can compete with the desired thiolates for surface sites. Here we present that gold nanoparticles deposited onto zeolite X can be used to remove these contaminants by chemisorption. This nanoparticle-impregnated zeolite does not only show high capacities for surface-active contaminants, such as thiols, but can be fully regenerated via a simple pyrolysis protocol.
doi:10.3762/bjnano.5.139
PMCID: PMC4142897  PMID: 25161861
ethanol; gold nanoparticles; purification; self-assembled monolayers; solvent
2.  The oriented and patterned growth of fluorescent metal–organic frameworks onto functionalized surfaces 
Summary
A metal–organic framework (MOF) material, [Zn2(adc)2(dabco)] (adc = anthracene-9,10-dicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]­octane), the fluorescence of which depends on the loading of its nanopores, was synthesized in two forms: as free-flowing nanocrystals with different shapes and as surface-attached MOFs (SURMOFs). For the latter, we used self-assembled monolayers (SAMs) bearing functional groups, such as carboxylate and pyridyl groups, capable of coordinating to the constituents of the MOF. It could be demonstrated that this directed coordination also orients the nanocrystals deposited at the surface. Using two different patterning methods, i.e., microcontact printing and electron-beam lithography, the lateral distribution of the functional groups could be determined in such a way that the highly localized deposition of the SURMOF films became possible.
doi:10.3762/bjnano.3.66
PMCID: PMC3458603  PMID: 23019553
electron-beam lithography; irradiation-promoted exchange reaction; microcontact printing; radiation-induced nanostructure; self-assembled monolayer; surface-attached metal–organic framework
3.  Directed deposition of silicon nanowires using neopentasilane as precursor and gold as catalyst 
Summary
In this work the applicability of neopentasilane (Si(SiH3)4) as a precursor for the formation of silicon nanowires by using gold nanoparticles as a catalyst has been explored. The growth proceeds via the formation of liquid gold/silicon alloy droplets, which excrete the silicon nanowires upon continued decomposition of the precursor. This mechanism determines the diameter of the Si nanowires. Different sources for the gold nanoparticles have been tested: the spontaneous dewetting of gold films, thermally annealed gold films, deposition of preformed gold nanoparticles, and the use of “liquid bright gold”, a material historically used for the gilding of porcelain and glass. The latter does not only form gold nanoparticles when deposited as a thin film and thermally annealed, but can also be patterned by using UV irradiation, providing access to laterally structured layers of silicon nanowires.
doi:10.3762/bjnano.3.62
PMCID: PMC3458599  PMID: 23019549
chemical vapor deposition; gold; nanoparticle; patterning; radiation-induced nanostructures; vapor-liquid-solid mechanism

Results 1-3 (3)