Controlling structure and morphology of CoPt nanoparticles through dynamical or static coalescence effects.
The structure and morphology of 1 to 3 nm size CoPt nanoparticles have been investigated in situ and in real time under different conditions: growth at 500 degrees C or at room temperature (RT) followed by annealing at 500 degrees C. The small-angle x-ray scattering measurements show size and temperature dependent growth mode with particle motions on the surface, while wide-angle scattering results, supported by Monte Carlo simulations, allow structure identification. If icosahedra are systematically detected at the first growth stages at RT, annealing at 500 degrees C yields the decahedral structure from the quasistatic coalescence of icosahedral morphology. Meanwhile, growth at 500 degrees C proceeds by a dynamical coalescence mechanism at the early stage, yielding truncated octahedral cubic structures.
Centre de Recherche sur la Matière Divisée, UMR 6619 Université d'Orléans & CNRS, 1 bis, rue de la Férollerie, 45071 Orléans Cedex, France.
J
J
Penuelas
P
P
Andreazza
C
C
Andreazza-Vignolle
H C N
HC
Tolentino
M
M
De Santis
C
C
Mottet