- 30.06.2021 -
FIM-S3 SEMINAR - Prof Lidia Martínez
Date and Time:Wednesday June 30th, 16:00 (SHARP))
LINK (Google Meet): https://meet.google.com/yud-upbp-mno
Speaker:
Prof Lidia Martínez - Instituto de Ciencia de Materiales de Madrid (Spain)
Title: Gas-phase synthesis of nanoparticles and their interaction with gases
Abstract: The growing interest in gas phase synthesis of nanoparticles is motivated by different factors like the capacity to fabricate nanoparticles out-of-thermodynamic equilibrium process or the need of solvent- free methods that enable greener approaches for nanoparticle production [1]. Among different types of cluster sources [2], in this seminar I will present some examples of nanoparticles fabricated with two different sputter gas aggregation sources developed at my research group. One of these systems consists in the replacement of a standard magnetron by a full-face erosion magnetron to avoid the racetrack formation [3]. The other system is a multi-magnetron GAS, called Multiple Ion cluster Source (MICS), to fabricate nanoparticles with controllable and tunable size, composition and structure [5,6]. In both cases, additional gases (apart from the sputtering gas) are injected during the fabrication process. It is known that traces of gases can have important effects on the clustering process that induces changes in cluster size and synthesis rates. However, it is less known the fact that these gases can also lead to new unexpected geometries. For instance, core-satellite gold nanoparticle complexes can be formed by the controlled injection of H2O molecules (figure 1, top) [4].
Some years ago, we succeeded to scale-up the MICS system using three independent magnetrons of 2” and a redesigned aggregation zone [7]. I will present details of the scaled-up MICS, the capacity to inject gases at different positions of the aggregation zone, avoiding poisoning of the target due to reactive gases. Controlled experiments of in-situ oxidation of Cu nanoparticles are presented as a model system to evaluate the capacity of this new design. Finally, I will present the fabrication of carbonaceous clusters and nanoparticles and their interaction with different gases [8,9]. Among them, the most interesting system is the interaction between carbon and hydrogen. We will see how the injection of controlled doses of hydrogen in the aggregation zone completely changes the morphology of the species formed and, depending on the dose, different architectures are found (figure1, middle, bottom) [10].
References
[1] R.E. Palmer, R. Cai, and J. Vernieres, Acc. Chem. Res., 51 (2018) 2296.
[2] Gas-phase Synthesis of nanoparticles, WILEY-VCH Verlag (2017). Edited by Yves Huttel.
[3] Y. Huttel, L. Martínez, A. Mayoral, I. Fernández, MRS Commun., 8 (2018) 947.
[4] J. Zhao et al., J. Phys. Chem. C, 124 (2020) 24441-24450.
[5] L. Martínez et al., Langmuir, 28 (2012) 11241.
[6] D. Llamosa P et al., Nanoscale, 6 (2014) 13483.
[7] L. Martínez et al., Scientific Reports, 8 (2018) 7250.
[8] G. Santoro et al., The Astrophysical Journal, 895 (2020) 97.
[9] L. Martínez et al., Nature Astronomy, 4 (2020) 97.
[10] L. Martinez et al., submitted; L. Martínez et al., in preparation.
Host: Marco Gibertini (FIM, UNIMORE) and Claudia Cardoso (S3, CNR-NANO)
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