Alloying processes in nanometre-size Ag@Au and Au@Ag core@shell particles are studied via high resolution Transmission Electron Microscopy (TEM) imaging.

While laser ablation in combination with electron impact mass spectroscopy yield numerous fragments and reaction products, helium-mediated mass analysis reveals the sublimation from bulk in units of (V2O5)2.

Diamantane clusters formed inside superfluid helium nanodroplets were analyzed by time-of-flight mass spectrometry. Distinct cluster sizes were identified as “magic numbers” and the corresponding feasible structures for clusters consisting of...

Nanoparticles with tunable localized surface plasmon resonance have been prepared by synthesis in helium nanodroplets. Subsequent surface deposition allows for the formation of substrates which can be employed for surface-enhanced Raman spectroscopy (SERS). The assembly of Ag@Au core@shell clusters of about 5 nm diameter in helium droplets with different Ag:Au ratio allows to tune the surface plasmon resonance between the plain Ag resonance at 447 nm and the Au resonance at 555 nm. For the fabricated substrates only a single plasmon resonance is observed in the UV/vis absorption spectra. The prepared nanostructures have been functionalized with 4-methylbenzenethiol (4-MBT) molecules and SERS spectra have been recorded. The results demonstrate the potential of the helium droplet synthesis approach, opening up a new route to the formation of tailored plasmonic nanoparticles and functional nanostructures.