Limits...
Laser-induced transformation of supramolecular complexes: approach to controlled formation of hybrid multi-yolk-shell Au-Ag@a-C:H nanostructures.

Manshina AA, Grachova EV, Povolotskiy AV, Povolotckaia AV, Petrov YV, Koshevoy IO, Makarova AA, Vyalikh DV, Tunik SP - Sci Rep (2015)

Bottom Line: It has been demonstrated that variation of the experimental parameters such as type of the organometallic precursor, solvent, deposition geometry and duration of laser irradiation allows directed control of nanoparticles' dimension and morphology.The mechanism of Au-Ag@a-C:H nanoparticles formation is suggested: the photo-excitation of the precursor molecule through metal-to-ligand charge transfer followed by rupture of metallophilic bonds, transformation of the cluster core including red-ox intramolecular reaction and aggregation of heterometallic species that results in the hybrid metal/carbon nanoparticles with multi-yolk-shell architecture formation.It has been found that the nanoparticles obtained can be efficiently used for the Surface-Enhanced Raman Spectroscopy label-free detection of human serum albumin in low concentration solution.

View Article: PubMed Central - PubMed

Affiliation: Institute of Chemistry, St. Petersburg State University, Universitetskii pr. 26, St. Petersburg, 198504, Russia.

ABSTRACT
In the present work an efficient approach of the controlled formation of hybrid Au-Ag-C nanostructures based on laser-induced transformation of organometallic supramolecular cluster compound is suggested. Herein the one-step process of the laser-induced synthesis of hybrid multi-yolk-shell Au-Ag@a-C:H nanoparticles which are bimetallic gold-silver subnanoclusters dispersed in nanospheres of amorphous hydrogenated a-C:H carbon is reported in details. It has been demonstrated that variation of the experimental parameters such as type of the organometallic precursor, solvent, deposition geometry and duration of laser irradiation allows directed control of nanoparticles' dimension and morphology. The mechanism of Au-Ag@a-C:H nanoparticles formation is suggested: the photo-excitation of the precursor molecule through metal-to-ligand charge transfer followed by rupture of metallophilic bonds, transformation of the cluster core including red-ox intramolecular reaction and aggregation of heterometallic species that results in the hybrid metal/carbon nanoparticles with multi-yolk-shell architecture formation. It has been found that the nanoparticles obtained can be efficiently used for the Surface-Enhanced Raman Spectroscopy label-free detection of human serum albumin in low concentration solution.

No MeSH data available.


Related in: MedlinePlus

(a) Au 4f and (b) Ag 3d PE core-level spectra obtained for the Au–Ag NPs (red) and precursor 1 (green).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4495562&req=5

f6: (a) Au 4f and (b) Ag 3d PE core-level spectra obtained for the Au–Ag NPs (red) and precursor 1 (green).

Mentions: Figure 6 shows the Au 4f (a) and Ag 3d (b) PE core-level spectra of the hybrid Au-Ag NPs and the precursor complex 1, dashed lines indicate the positions of the bulk metal bands. The structure of 1 spectra corresponds to those of the Au(I) and Ag(I) compounds as it was discussed previously25. For the laser-induced NPs we observe asymmetric Au 4f peaks which are shifted towards higher BE by ~0.4 eV relatively to the bulk Au. The asymmetric band shape tailing to higher energy can be explained by the presence of significant lognormal cluster size-distribution40. The evaluation of the Ag 3d spectra of hybrid NPs revealed higher energy BE shift of ca. 0.1 eV relative to the bulk metal value. It is worth mentioning that analysis of the NPs size in terms of the cluster-size effect without consideration of the Au−Ag alloy formation may result in overestimation the NPs size from the Ag 3d core-level BE measurements and, at the same time, underestimation from the Au 4f spectra. For example the values obtained from analysis of the Ag 3d spectrum37 amount to ca. 6 nm whereas the corresponding value drops down to ca. 2 nm calculated using the Au 4f BE shift40. The real NPs’ mean size seems to be in-between, i.e. 3–5 nm. This estimation is in good agreement with the results obtained by SEM and TEM.


Laser-induced transformation of supramolecular complexes: approach to controlled formation of hybrid multi-yolk-shell Au-Ag@a-C:H nanostructures.

Manshina AA, Grachova EV, Povolotskiy AV, Povolotckaia AV, Petrov YV, Koshevoy IO, Makarova AA, Vyalikh DV, Tunik SP - Sci Rep (2015)

(a) Au 4f and (b) Ag 3d PE core-level spectra obtained for the Au–Ag NPs (red) and precursor 1 (green).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4495562&req=5

f6: (a) Au 4f and (b) Ag 3d PE core-level spectra obtained for the Au–Ag NPs (red) and precursor 1 (green).
Mentions: Figure 6 shows the Au 4f (a) and Ag 3d (b) PE core-level spectra of the hybrid Au-Ag NPs and the precursor complex 1, dashed lines indicate the positions of the bulk metal bands. The structure of 1 spectra corresponds to those of the Au(I) and Ag(I) compounds as it was discussed previously25. For the laser-induced NPs we observe asymmetric Au 4f peaks which are shifted towards higher BE by ~0.4 eV relatively to the bulk Au. The asymmetric band shape tailing to higher energy can be explained by the presence of significant lognormal cluster size-distribution40. The evaluation of the Ag 3d spectra of hybrid NPs revealed higher energy BE shift of ca. 0.1 eV relative to the bulk metal value. It is worth mentioning that analysis of the NPs size in terms of the cluster-size effect without consideration of the Au−Ag alloy formation may result in overestimation the NPs size from the Ag 3d core-level BE measurements and, at the same time, underestimation from the Au 4f spectra. For example the values obtained from analysis of the Ag 3d spectrum37 amount to ca. 6 nm whereas the corresponding value drops down to ca. 2 nm calculated using the Au 4f BE shift40. The real NPs’ mean size seems to be in-between, i.e. 3–5 nm. This estimation is in good agreement with the results obtained by SEM and TEM.

Bottom Line: It has been demonstrated that variation of the experimental parameters such as type of the organometallic precursor, solvent, deposition geometry and duration of laser irradiation allows directed control of nanoparticles' dimension and morphology.The mechanism of Au-Ag@a-C:H nanoparticles formation is suggested: the photo-excitation of the precursor molecule through metal-to-ligand charge transfer followed by rupture of metallophilic bonds, transformation of the cluster core including red-ox intramolecular reaction and aggregation of heterometallic species that results in the hybrid metal/carbon nanoparticles with multi-yolk-shell architecture formation.It has been found that the nanoparticles obtained can be efficiently used for the Surface-Enhanced Raman Spectroscopy label-free detection of human serum albumin in low concentration solution.

View Article: PubMed Central - PubMed

Affiliation: Institute of Chemistry, St. Petersburg State University, Universitetskii pr. 26, St. Petersburg, 198504, Russia.

ABSTRACT
In the present work an efficient approach of the controlled formation of hybrid Au-Ag-C nanostructures based on laser-induced transformation of organometallic supramolecular cluster compound is suggested. Herein the one-step process of the laser-induced synthesis of hybrid multi-yolk-shell Au-Ag@a-C:H nanoparticles which are bimetallic gold-silver subnanoclusters dispersed in nanospheres of amorphous hydrogenated a-C:H carbon is reported in details. It has been demonstrated that variation of the experimental parameters such as type of the organometallic precursor, solvent, deposition geometry and duration of laser irradiation allows directed control of nanoparticles' dimension and morphology. The mechanism of Au-Ag@a-C:H nanoparticles formation is suggested: the photo-excitation of the precursor molecule through metal-to-ligand charge transfer followed by rupture of metallophilic bonds, transformation of the cluster core including red-ox intramolecular reaction and aggregation of heterometallic species that results in the hybrid metal/carbon nanoparticles with multi-yolk-shell architecture formation. It has been found that the nanoparticles obtained can be efficiently used for the Surface-Enhanced Raman Spectroscopy label-free detection of human serum albumin in low concentration solution.

No MeSH data available.


Related in: MedlinePlus