Over the past few decades, the nano-size particles research and especially metallic nanoparticles have received significant attention due to their unique properties that are extremely distinct from their bulk counterparts as a result of their high surface-to-volume ratio. Silver and gold nanoparticles are amongst the most exploited nanomaterials because of their promising applications in a broad range of fields. Plasma discharges of different configurations proved to be efficient as no toxic reducing agents are needed. In particular, plasma jet in contact with a liquid which is a simple and fast technique for the synthesis of metal nanoparticles. Its main advantage is the variety of species present in the plasma plume which can induce rapid chemical reactions in the solution. The dielectric barrier discharge (DBD) jet is the most commonly used cold plasma jet configuration and generally consists of a noble gas passing through a dielectric capillary, impinging into the ambient air. They are characterized by the presence of a dielectric layer touching the discharge between the two electrodes that are connected to a power supply. When the required voltage is applied through the electrodes around the capillary, a stable and continuous plume of plasma could be produced. This plasma discharge generates a variety of radicals and reactive molecules such as reactive oxygen and nitrogen species (RONS). This thesis is structured into two main parts, each employing a distinct plasma jet configuration for the synthesis of metallic nanoparticles. The first part revolves around the utilization of a helium atmospheric pressure plasma jet, featuring an asymmetric borosilicate glass source connected to a pulse power supply. This section delves into the production of both silver and gold nanoparticles, separately. A comprehensive investigation is carried out, exploring the impact of plasma exposure duration, precursor concentration, and capping agent concentration on the characteristics of the nanoparticles synthesized. In the second part of this thesis, a different plasma configuration is investigated. Here, a dual-frequency atmospheric pressure plasma jet, comprised of an alumina tube connected to both the pulsed power supply and an RF power generator, is employed. This configuration is leveraged to study the synthesis of gold nanoparticles. The investigation within this part centers on understanding the effects and implications of key physical process parameters, including the choice of process gas and the addition of RF power levels on the characteristics of the synthesized gold nanoparticles.
T. Habib, J. M. A. Caiut, et B. Caillier, "Synthesis of silver nanoparticles by atmospheric pressure plasma jet", Nanotechnology, vol. 33, no 32, p. 325603, may 2022 (https://doi.org/10.1088/1361-6528/ac6528).
E. G. Hilario, T. Habib, C. V. T. Maciel, R. F. Da Silva, D. F. Luz, G. S. Soares, B. Cailiier C. Jacinto, L. Maia, J. M. A. Caiut, A. L. Moura, "Metallic nanoparticles-decorated NdxY1xA13(B03)4 sub-micrometric particles to enhance anti-Stokes excitation performance", Optical Materials: X, vol. 19, p. 100254, Jul. 2023 (https://doi.org/10.1016/j.omx.2023.100254).
T. Habib, L. Ceroni, A. Patelli, J. M. A. Caiut and B. Caillier, " Impact of Micropulse and Radio Frequency Coupling in an Atmospheric Pressure Plasma Jet on the Synthesis of Gold Nanoparticles ", Plasma MDPI, oct. 2023.
- M. Jerome FRESNAIS, Sorbonne University Reviewer
- Mme Sandra CRUZ, Federal University of São Carlos Reviewer
- M. Marc VERELST, CEMES Examiner
- M. Sidney J.L. RIBEIRAO, São Paulo State University Examiner
- M. Bruno CAILLIER, INU Champollion Supervisor
- M. José Mauricio A. CAIUT, University of São Paulo Co-supervisor
- Mme Rogéria R. GONÇALVES, University of São Paulo Invited
- M. Alessandro PATELLI, University of Padua Invited