Abstract: The pressure dependence of the plasmonic properties, crystal structure, and of gold nanoparticles are analyzed using colloids of single-crystal (SC-AuNP) and penta-twinned (PT-AuNP) gold nanoparticles by XRD, TEM, and optical extinction spectroscopy. Unlike the fcc crystal structure of SC AuNPs, the PT-AuNPs demonstrate allotropism, presenting either a body-centered tetragonal (I4/mmm) or orthorhombic (Immm) structure, depending on their shape: I4/mmm for decahedra, and Immm for rods and bipyramids. Our pressure dependence studies indicate that, under hydrostatic conditions (liquid solution), the equation of state for individual gold nanoparticles can be accurately determined. In contrast, non-hydrostatic effects produce axial stresses on nanoparticle that can be up to a factor 10× higher than those on the bulk metal. We analyze the impact of these non-hydrostatic effects on the mechanical stability and plasmonic behavior of both types of nanoparticles. Notably, PT AuNPs demonstrate superior mechanical stability compared to SC AuNPs, despite having similar bulk moduli, enhancing their sensing capabilities, particularly in non-hydrostatic pressure conditions.

About the speaker: Fernando Rodriguez is a Professor of Condensed Matter Physics at the University of Cantabria. He held postdoctoral and invited scientist positions at the Universities of Bern, King's College London, and Colorado State University, where he was also Affiliate member. His expertise in spectroscopic characterization of micro- and nanostructured materials under extreme conditions, and optically active glasses for energy use. He served as Chairman of the European High Pressure Research Group, and as Vice President, and President of the International Association for the Advancement of High-Pressure Science and Technology (AIRAPT). He was awarded the XXII Investigation Price "Juan Maria Parés" of the Social Council, University of Cantabria

Inviter: 靳常青

Contact: 邓正 82649163