1
artículo
Publicado 2020
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Dysprosium (Dy3+)-doped tin oxide (SnO2) nanoparticles (NPs) have been successfully synthesized using the chemical polymer precursor method. This material blends the holding matrix’s electronic properties with dysprosium’s optical and magnetic properties, making it a promising material for technological applications. X-ray diffraction patterns and the Raman spectra of all NPs indicated the formation of only the SnO2 phase. The decrease in particle size (from ~ 11 to ~ 6 nm) and increase in lattice parameters depending on the Dy content were determined. The latter proves the solid solution between Sn and Dy ions, which is in agreement with the ionic radii mismatch between them. Transmission electron microscopy (TEM) confirms the particle size and size reduction observed through XRD. X-ray photoelectron spectroscopy (XPS) results suggest a change of the oxidation state from Sn4+ to Sn2...
2
artículo
Publicado 2021
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We describe a simple method for the preparation of gold-decorated silica (SiO2) nanoparticles (NPs) by the in situ precipitation method using simple BH4? ions reduction as a procedure, where BH4? ions are adsorbed onto PEI-functionalized SiO2 NPs for stabilizing and reducing gold ions onto PEI-SiO2 surface in water under ambient conditions. The result was 3-nm gold nanoshell NPs attached to SiO2 core (~ 75 nm) with a surface plasmon resonance (SPR) at ~ 680 nm. SPR band is associated with Au NP aggregates that arise from strong interparticle interaction. This is an alternative to the gold-seeding methods and the use of anionic gold species for the obtention of gold-decorated SiO2 NPs with an important red-shift in UV–Vis absorption and with potential applications in biosensors and photothermal therapy.
3
artículo
Publicado 2021
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Fe-doped indium tin oxide (ITO) is an exciting material because it combines the host matrix's good electrical conductivity with the magnetic properties coming from the most earth-abundant transition metal, Fe. In this regard, a single-pot synthesis route based on a polymeric precursor method has been used to produce high-quality undoped and iron-doped ITO with iron content up to 13.0 mol%. The crystal formation in the bixbyite-type structure of all samples is confirmed by X-ray diffraction data analysis. A monotonous decrease of the lattice parameters with the increase of the Fe content is determined, which is consistent with of Fe ions with an oxidation state of 3+ in agreement with the ionic radii difference between In3+ and Fe3+. Raman spectroscopy confirms the bixbyite structure formation and provides evidence of a high surface disorder. 119Sn Mössbauer spectroscopy reveals the form...