Anna Giusti

Magnetic Bistability of Individual Single-Molecule Magnets Grafted on Single-Wall Carbon Nanotubes†

A POM to remember: Hexanuclear Fe(III) polyoxometalate (POM) single-molecule magnets (see structure) can be noncovalently assembled on the surface of single-wall carbon nanotubes. Complementary characterization techniques (see TEM image and magnetic hysteresis loops) demonstrate the integrity and bistability of the individual molecules, which could be used to construct single-molecule memory devices.

Dendrimer-Capped Nanoparticles Prepared by Picosecond Laser Ablation in Liquid Environment

Fifth generation ethylendiamine-core poly(amidoamine) (PAMAM G5) is presented as an efficient capping agent for the preparation of metal and semiconductor nanoparticles by ps laser ablation in water. In particular, we describe results obtained with the fundamental, second and third harmonic of a ps Nd:YAG laser and the influence of laser wavelength and pulse energy on gold particle production and subsequent photofragmentation. In this framework, the role of the dendrimer and, in particular, its interactions with gold clusters and cations are accounted.

Production and photofragmentation of Au nanoparticles by 355 nm picosecond radiation

Fifth generation ethylendiamine-core poly(amidoamine) (PAMAM G5)-capped-gold-nanoparticles were prepared by ps laser ablation in water, by using the third harmonic of a ps Nd:YAG laser. Post-irradiation with the same wavelength causes efficient photofragmentation of the nanoparticles. We performed a comparison with analogous tests carried out with 532 nm ps pulses. We found that, while 532-nm-fragmentation is a 2-photon photoelectric process, 355-nm-fragmentation is linear.

INVESTIGATION OF NANOSTRUCTURED METAL/POLYMER INTERFACES BY SURFACE ENHANCED RAMAN SCATTERING

Surface Enhanced Raman Scattering (SERS) experiments were performed on different interfaces consisting of nanostructured metals and ultra-thin layers of conjugated polymers. The Raman electromagnetic enhancement ensured by the surface roughness of different metals (Au, Ag or Al) permitted the monitoring of the optical and spectroscopic properties of ultra-thin polymer layers. In particular, in the case of a novel carbazolyldiacetylene deposited by self assembling on rough silver films or used as a capping agent for gold nanoparticles and subsequently polymerized by UV radiation, SERS experiments permitted detection of two polymer phases, characterized by a different degree of order in the polymer backbone: the highly conjugated blue phase and the less-extended red conformation.