Formation of silver nanoparticles by laser irradiation: an ab initio investigation

• Grant number: 21/09187-2
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: October 20, 2022
• End date: October 19, 2023
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Edison Zacarias da Silva
• Grantee: Luis Antônio Cabral
• Supervisor: Juan Manoel Andres Bort
• Host Institution: Instituto de Física Gleb Wataghin (IFGW). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Universitat Jaume I, Spain
• Associated to the scholarship: 18/20729-9 - Formation of Ag Nanoparticles by Laser Irradiation: An ab inicio Investigation, BP.PD

Abstract

The functionalization of materials is a complex endeavor and the challenges tasks for a precise theoretical description require notable computation skills. Due to the wide range of theoretical methodologies available for this study, defining an investigation path becomes crucial for a good understanding of the obtained results. In this project we are proposing an ab initio investigation using the two-temperature model to describe the femtosecond laser effects on silver-based materials aiming to obtain applications in nanodevices. The faster electrons response than the ions for the irradiation provokes their excitation from the ground state. If the energy given by the laser is higher than the band-gap region, the closer electrons from the Fermi energy will populate the unoccupied levels of the conduction band, while for an intense laser irradiation, the deeper electrons in the valence band will be excited. The smearing methods within the DFT-finite temperature approach allow to understand and simulate the electronic excitation. This is a non-equilibrium condition and the relaxation process is accompanied by the phonon dispersion. Also, the laser heating of the ions is revealed by their kinetic energy and, to simulate the effects of the lattice temperature, the ab initio molecular dynamics will be employed. Thus, the electronic excitation will be described by the DFT-finite temperature and the lattice heating by the ab initio molecular dynamics, both in a single methodology called two-temperature model. The investigation of the laser effects opens the possibility to functionalize, predict and novel new materials. According to the experimental results of our collaborators, the intense laser irradiation provides the break of the chemical bonds and agglomeration of the silver atoms until the formation of nanoparticules (NPs)on the surface of the host material. All investigations proposed in this project will be concomitantly with the findings of our experimental collaborators. In addition, the analysis of the silver-NPs will allow to direct our results for nanotechnology and nanomedicine applications, such as the bactericidal and antiviral properties. Thus, we expected that our theoretical investigations guide the experiments of our collaborators and contribute to the development of the material functionalization technique by femtosecond laser irradiation. (AU)