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Multicomponent signal unmixing from nanoheterostructures: overcoming the traditional challenges of nanoscale X-ray analysis via machine learning.

Rossouw D, Burdet P, de la Peña F, Ducati C, Knappett BR, Wheatley AE, Midgley PA - Nano Lett. (2015)

Bottom Line: The chemical composition of core-shell nanoparticle clusters have been determined through principal component analysis (PCA) and independent component analysis (ICA) of an energy-dispersive X-ray (EDX) spectrum image (SI) acquired in a scanning transmission electron microscope (STEM).The method blindly decomposes the SI into three components, which are found to accurately represent the isolated and unmixed X-ray signals originating from the supporting carbon film, the shell, and the bimetallic core.The composition of the latter is verified by and is in excellent agreement with the separate quantification of bare bimetallic seed nanoparticles.

View Article: PubMed Central - PubMed

Affiliation: †Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom.

ABSTRACT
The chemical composition of core-shell nanoparticle clusters have been determined through principal component analysis (PCA) and independent component analysis (ICA) of an energy-dispersive X-ray (EDX) spectrum image (SI) acquired in a scanning transmission electron microscope (STEM). The method blindly decomposes the SI into three components, which are found to accurately represent the isolated and unmixed X-ray signals originating from the supporting carbon film, the shell, and the bimetallic core. The composition of the latter is verified by and is in excellent agreement with the separate quantification of bare bimetallic seed nanoparticles.

No MeSH data available.


Related in: MedlinePlus

Comparison between rawEDX spectra extracted from a FePt bimetallicseed particle (top) and from an iron oxide particle (bottom) withIC#0 and IC#1, respectively. The FePt seed and Fe3O4 X-ray signals are summed over several particles.
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fig6: Comparison between rawEDX spectra extracted from a FePt bimetallicseed particle (top) and from an iron oxide particle (bottom) withIC#0 and IC#1, respectively. The FePt seed and Fe3O4 X-ray signals are summed over several particles.

Mentions: A comparisonof raw EDX spectra extractedfrom FePt bimetallic seed particles and from pure Fe3O4 particles with IC#0 and IC#1, respectively, is provided inFigure 6. In both cases, the ICs were scaledby a constant to obtain a best fit to the raw spectra. Despite thestrong overall agreement in each case, some differences are seen forindividual X-ray peaks. The carbon peak difference in both cases iscaused by the separation of carbon into a different component (IC#2).The difference in the shell Cu peaks are not due to a compositionaldifference as the Cu signal is spurious in origin. The iron oxideparticle spectrum also contains small silicon and sulfur peaks whichlikely originate from residue on the carbon film. The difference inthe Pt Mα core peak may be due to the attenuation of Pt MαX-rays in the shell of the core–shell nanoparticles and innearby particles along the trajectory to the detector. The strongoverall similarity between the raw and IC spectra provide direct evidenceshowing that the spectral components extracted by ICA from the core–shellspectrum image data are strongly representative of the buried core,surrounding shell, and carbon support compositions.


Multicomponent signal unmixing from nanoheterostructures: overcoming the traditional challenges of nanoscale X-ray analysis via machine learning.

Rossouw D, Burdet P, de la Peña F, Ducati C, Knappett BR, Wheatley AE, Midgley PA - Nano Lett. (2015)

Comparison between rawEDX spectra extracted from a FePt bimetallicseed particle (top) and from an iron oxide particle (bottom) withIC#0 and IC#1, respectively. The FePt seed and Fe3O4 X-ray signals are summed over several particles.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4440406&req=5

fig6: Comparison between rawEDX spectra extracted from a FePt bimetallicseed particle (top) and from an iron oxide particle (bottom) withIC#0 and IC#1, respectively. The FePt seed and Fe3O4 X-ray signals are summed over several particles.
Mentions: A comparisonof raw EDX spectra extractedfrom FePt bimetallic seed particles and from pure Fe3O4 particles with IC#0 and IC#1, respectively, is provided inFigure 6. In both cases, the ICs were scaledby a constant to obtain a best fit to the raw spectra. Despite thestrong overall agreement in each case, some differences are seen forindividual X-ray peaks. The carbon peak difference in both cases iscaused by the separation of carbon into a different component (IC#2).The difference in the shell Cu peaks are not due to a compositionaldifference as the Cu signal is spurious in origin. The iron oxideparticle spectrum also contains small silicon and sulfur peaks whichlikely originate from residue on the carbon film. The difference inthe Pt Mα core peak may be due to the attenuation of Pt MαX-rays in the shell of the core–shell nanoparticles and innearby particles along the trajectory to the detector. The strongoverall similarity between the raw and IC spectra provide direct evidenceshowing that the spectral components extracted by ICA from the core–shellspectrum image data are strongly representative of the buried core,surrounding shell, and carbon support compositions.

Bottom Line: The chemical composition of core-shell nanoparticle clusters have been determined through principal component analysis (PCA) and independent component analysis (ICA) of an energy-dispersive X-ray (EDX) spectrum image (SI) acquired in a scanning transmission electron microscope (STEM).The method blindly decomposes the SI into three components, which are found to accurately represent the isolated and unmixed X-ray signals originating from the supporting carbon film, the shell, and the bimetallic core.The composition of the latter is verified by and is in excellent agreement with the separate quantification of bare bimetallic seed nanoparticles.

View Article: PubMed Central - PubMed

Affiliation: †Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom.

ABSTRACT
The chemical composition of core-shell nanoparticle clusters have been determined through principal component analysis (PCA) and independent component analysis (ICA) of an energy-dispersive X-ray (EDX) spectrum image (SI) acquired in a scanning transmission electron microscope (STEM). The method blindly decomposes the SI into three components, which are found to accurately represent the isolated and unmixed X-ray signals originating from the supporting carbon film, the shell, and the bimetallic core. The composition of the latter is verified by and is in excellent agreement with the separate quantification of bare bimetallic seed nanoparticles.

No MeSH data available.


Related in: MedlinePlus