This thesis was devoted first to the synthesis of size controlled silver nanoparticles. The nanoparticles are obtained by reducing a metallo-organic silver salt RAg(PPh3)n (R=Cl, Br or NO3 and n=1 or 3) with tert-butylamineborane in presence of alcanethiols. The flexible choice of functional group and number of PPh3 in these salts as well as of the reaction temperature allows us to obtain alkanethiol coated silver nanoparticles with diameter ranging from 2.5 to 7.1 nm, with a low size distribution. We get evidence that particle growth occurs via the ligand replacement of PPh3 by alkanethiol. Whereas under dry air, silver nanoparticles are stable, under ambient air, we observe their etching. This process is thus due to the oxidation of silver by the redox couple O2/H2O. By annealing organized silver nanoparticles at a mild temperature (50° C) during 4 days, we observe the formation of well crystallized silver triangles. Due to their uniformity in size and shape, silver nanoparticles have a strong tendency to form 3D supracrystals after deposition on a solid substrate. Their morphologies and crystalline structures are shown to depend on the nature of the solvent, alkanethiol chain length and nanoparticle size. Using low-frequency Raman scattering, we demonstrate that crystallinity of silver nanoparticles modifies their vibrations. We show that the self-organized silver nanoparticles can be used as Surface Enhanced Raman Scattering (SERS) substrate and provide a high SERS signal of alkanethiol ligands. Finally, we show that it is possible to successfully generalize this metallo-organic approach to the synthesis of copper nanoparticles with different sizes and shapes
Elaboration of silver nanoparticles by reduction of metallo-organic salts : size-control, stability, organization and physical properties