slides – Inorganic Nanoparticles Group

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Editor — Wed, 25 Apr 2018 13:07:40 +0000

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New Paper on the Size-Controlled Synthesis of Sub-10-nanometer Citrate-Stabilized Gold Nanoparticles Published in Chemistry of Materials.

Editor — Sat, 11 Mar 2017 16:42:59 +0000

The development of synthetic strategies for the controlled production of small Au nanoparticles (Au NPs) with accessible surface is of crucial important for the design of the final selectivity, activity and compatibility of Au NPs, especially in those (bio)applications where size is a critical parameter . In this work, we report a new synthetic method for the production of highly monodisperse, biocompatible and functionalizable sub-10-nm citrate-stabilized gold nanoparticles following a kinetically controlled seeded-growth strategy. We found how the use of traces of tannic acid together with an excess of sodium citrate during nucleation is fundamental in the formation of a high number of small ∼3.5 nm Au seeds. These seeds can be further grown, with nanometric resolution, to produce Au NPs with a precise control over their sizes between 3.5 and 10 nm. These samples allow studying the size-dependent optical properties in the small transition size regime lying between clusters and nanoparticles. The work has now been published in Chemistry of Materials under the title “Size-Controlled Synthesis of Sub-10-nanometer Citrate-Stabilized Gold Nanoparticles and Related Optical Properties.“

New Paper on the Study of the Localized Multipolar Surface Plasmon Resonances of Silver Nanoparticles Published in Langmuir.

Editor — Fri, 10 Mar 2017 19:33:43 +0000

Silver nanoparticles absorb and scatter light with extraordinary efficiency due to the collective oscillations of the conduction electrons of the metal surface when they are excited by light of an specific wavelengths. These oscillations, known as a localized surface plasmon resonances (LSPRs) are determined by the size, shape and local environment in which the nanoparticle is embedded. In this work, we have spectroscopically investigated the effect of the size and surface coating on the sensitivity of localized multipolar surface plasmon resonances in high-quality silver colloidal solutions with precisely controlled sizes from 10 to 220 nm and well-defined surface chemistry, identifying the size-dependence of dipolar, quadrupolar and octapolar modes. Besides, we studied how these multipolar resonances are affected by modifications of the NP’ surface coating, in particular the dependences on the length and the anchor group of the molecule attached at its surface, revealing the higher sensitivity of larger sizes, dipolar than higher-order modes, thiol than amine groups, and long than short molecules. We also extend this study to gold nanoparticles, aiming to compare the sensitivity of both materials, quantifying the higher sensitivity of silver. The work has now been published in Langmuir under the title “Quantifying the Sensitivity of Multipolar (Dipolar, Quadrupolar and Octapolar) Surface Plasmon Resonances in Silver Nanoparticles: The Effect of Size, Composition and Surface Coating.”

New Paper on High-Index Surface Platinum Hollow Nanocrystals Published in Journal of Materials Chemistry A.

Editor — Fri, 10 Mar 2017 17:58:03 +0000

One of the main focus of the group is the development of synthetic strategies for the production of advanced hollow NCs allowing the precise morphological control of its surface. This aspect, of critical importance for the understanding of the unique properties of the materials at the nanoscale, is also useful in a wide range of applications, such as catalysis, where the development of highly active and low-cost materials represents a landmark for the development of industrial technologies. This time we show how combining solid state chemistry techniques and colloidal synthesis allows us to prepare exotic materials, such as PtAg@Pt single-crystal hollow NCs with high-index planes, at room temperature (green temperature) by controlled corrosion of silver templates, which minimize Pt consumption and maximize surface reactivity. We are further working on the applicability use of these NC-based catalysts. The work, carried out with the collaboration of Prof. Jordi Arbiol from the Catalan Institute of Nanoscience and Nanotechnology (ICN2), has now been published in Journal of Materials Chemistry A under the title ” Enhanced reactivity of high-index surface platinum hollow nanocrystals“