We report on an experimental study of the coalescence-driven grow process of colloidal Au nanoparticles on SiO surface. Nanoparticles with 30, 50, 80, 100 nm nominal diameters on a SiO substrate were deposited, from solutions, by the drop-casting method. Then, annealing processes, in the 573-1173 K temperature range and 900-3600 s time range, were performed. Using scanning electron microscopy analyses, the temporal evolution of the nanoparticles sizes has been studied. In particular, for all classes of nanoparticles, the experimental-obtained diameters distributions evidenced double-peak shapes (i. e. bimodal distributions): a first peak centered (and unchanged changing the annealing temperature and/or time) at the nominal diameter of the as-deposited nanoparticles, <D>, and a second peak shifting at higher mean diameters, <D>, increasing the annealing temperature and/or time. This observation suggested us a coalescence-driven growth process of a nanoparticles sub-population. As a consequence, the temporal evolution of <D> (for each class of nanoparticles and each annealing temperature), within the well-established particles coalescence theoretical framework, has been analyzed. In particular, by the analyses of the experimental data using relations as prescribed by the theoretical model, a characteristic size-dependent activation energy for the Au nanoparticles coalescence process has been evaluated.

Experimental study on the coalescence process of SiO2 supported colloidal Au nanoparticles

Ruffino F;
2015

Abstract

We report on an experimental study of the coalescence-driven grow process of colloidal Au nanoparticles on SiO surface. Nanoparticles with 30, 50, 80, 100 nm nominal diameters on a SiO substrate were deposited, from solutions, by the drop-casting method. Then, annealing processes, in the 573-1173 K temperature range and 900-3600 s time range, were performed. Using scanning electron microscopy analyses, the temporal evolution of the nanoparticles sizes has been studied. In particular, for all classes of nanoparticles, the experimental-obtained diameters distributions evidenced double-peak shapes (i. e. bimodal distributions): a first peak centered (and unchanged changing the annealing temperature and/or time) at the nominal diameter of the as-deposited nanoparticles, , and a second peak shifting at higher mean diameters, , increasing the annealing temperature and/or time. This observation suggested us a coalescence-driven growth process of a nanoparticles sub-population. As a consequence, the temporal evolution of (for each class of nanoparticles and each annealing temperature), within the well-established particles coalescence theoretical framework, has been analyzed. In particular, by the analyses of the experimental data using relations as prescribed by the theoretical model, a characteristic size-dependent activation energy for the Au nanoparticles coalescence process has been evaluated.
2015
Activation energy
Annealing
Coalescence
Gold
Nanoparticles
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/427616
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