The effect of the oxidation of gallium nanoparticles (Ga NPs) on their plasmonic properties is investigated. Discrete dipole approximation has been used to study the wavelength of the out-of-plane localized surface plasmon resonance in hemispherical Ga NPs, deposited on silicon substrates, with oxide shell (GaO) of different thickness. Thermal oxidation treatments, varying temperature and time, were carried out in order to increase experimentally the GaO shell thickness in the NPs. The optical, structural and chemical properties of the oxidized NPs have been studied by spectroscopic ellipsometry, scanning electron microscopy, grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy. A clear redshift of the peak wavelength is observed, barely affecting the intensity of the plasmon resonance. A controllable increase of the GaO thickness as a consequence of the thermal annealing is achieved. In addition, simulations together with ellipsometry results have been used to determine the oxidation rate, whose kinetics is governed by a logarithmic dependence. These results support the tunable properties of the plasmon resonance wavelength in Ga NPs by thermal oxidation at low temperatures without significant reduction of the plasmon resonance intensity.
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Eur J Nucl Med Mol Imaging
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Institute of Radiation Medicine, Fudan University, Xietu Road 2094, Shanghai, 200032, China.
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View Article and Find Full Text PDFLangmuir
January 2025
Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States.
We synthesized rigid, macromolecular brushes with well-defined and quantized brush lengths on a gold nanoparticle substrate by using a macromolecular "grafting from" approach. The macromonomers used in these brushes were thiol- and maleimide-functionalized peptide coiled coil "bundlemers" that fold into discrete 4 nm × 2 nm (length × diameter) cylindrical nanoparticles. With each added peptide macromonomer layer, brush thickness increased by approximately the length of a single bundlemer nanoparticle.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou, 434023, P.R. China.
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View Article and Find Full Text PDFJ Chem Inf Model
January 2025
Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States.
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