Chemical composition dispersion in bi-metallic nanoparticles: Semi-automated analysis using HAADF-STEM

T. Epicier (1) , K. Sato , F. Tournus (2) , T. Konno

1 MATEIS - Matériaux, ingénierie et science [Villeurbanne]
2 LPMCN - Laboratoire de Physique de la Matière Condensée et Nanostructures

We present a method using high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) to determine the chemical composition of bi-metallic nanoparticles. This method, which can be applied in a semi-automated way, allows large scale analysis with a statistical number of particles (several hundreds) in a short time. Once a calibration curve has been obtained, e.g., using energy-dispersive X-ray spectroscopy (EDX) measurements on a few particles, the HAADF integrated intensity of each particle can indeed be directly related to its chemical composition. After a theoretical description, this approach is applied to the case of iron-palladium nanoparticles (expected to be nearly stoichiometric) with a mean size of 8.3 nm. It will be shown that an accurate chemical composition histogram is obtained, i.e., the Fe content has been determined to be 49.0 at.% with a dispersion of 10.4 %. HAADF-STEM analysis represents a powerful alternative to fastidious single particle EDX measurements, for the compositional dispersion in alloy nanoparticles. © Springer Science+Business Media B.V. 2012.

Mots clés: Alloy nanoparticle; Bimetallic nanoparticles; Calibration curves; Chemical compositions; Energy dispersive x-ray spectroscopy; Fe content; HAADF-STEM; High-angle annular dark fields; Integrated intensities; Iron-palladium; Large-scale analysis; Mean size; Scanning tem; Semi-automated; Semi-automated analysis; Single particle; Statistical numbers; STEM-HAADF; Dispersions; Energy dispersive spectroscopy; Transmission electron microscopy; Nanoparticles; iron; nanoparticle; palladium; article; calibration; chemical composition; dispersion; high angle annular dark field scanning transmission electron microscopy; histogram; particle size; priority journal; scanning transmission electron microscopy

Domaines: Matériaux

T. Epicier, K. Sato, F. Tournus, T. Konno. Chemical composition dispersion in bi-metallic nanoparticles: Semi-automated analysis using HAADF-STEM. Journal of Nanoparticle Research, 2012, 14 (9), ⟨10.1007/s11051-012-1106-z⟩. ⟨hal-01834929⟩