Description du sujet de thèse

This research project aims to explore and master polymorphism in multicomponent systems, focusing specifically on nanorods as a promising shape for advanced self-assembly. Thus far, multicomponent self-assembly has been extensively studied for mixtures of nanospheres, where complex binary crystals and quasicrystals can form, with maximum packing densities exceeding that of the densest single-component face-centered cubic (FCC) arrangement. We hypothesize that binary nanorods mixtures offer even more intriguing possibilities. Their elongated shape naturally drives the formation of layered phases with either smectic or crystalline order, resulting in anisotropic optical and electronic properties that fundamentally differ from those of isotropic nanospheres. We will focus on noble metal (Au, Ag) nanorods because of both their tunability in shape, and their unique plasmonic properties, giving rise to asssemblies with enhanced plasmonic functionalities. Hence our aim is to decipher design rules for the fabrication of new plasmonic materials. Our central hypothesis is that mixtures of nanorods with varying dimensions will form more compact structures than single-component assemblies, leading to binary lattices with unique architectures, including tunable porosity, diverse lattice symmetries, and even aperiodicity. The PhD project will primarily focus on colloidal chemistry and self-assembly, with emphasis on nanoparticle synthesis, their characterization (microscopy, scattering, spectroscopy), data analysis, and dissemination of results (presentations, publications).

Contexte de travail

The Laboratoire de Physique des Solides (LPS) is a joint research unit (UMR 8502) of Université Paris-Saclay and the CNRS. It is affiliated with the CNRS Institute of Physics and the 28th section of the French National Council of Universities. The LPS is also a member of the Friedel-Jacquinot Federation, a coordination structure for physics on the Moulon plateau in Orsay (Île-de-France). The laboratory hosts around one hundred researchers and faculty members, both experimentalists and theorists, supported by about sixty engineers, technicians, and administrative staff. Each year, the LPS welcomes a large number of undergraduate and graduate students, including many PhD candidates, as well as postdoctoral researchers and visiting scientists. Despite its name, the laboratory covers a much broader range of topics, aiming to address the full diversity of condensed matter physics. Research at the LPS is organized around three main thematic areas, each involving roughly the same number of scientists:
- New electronic states of matter
- Physical phenomena at reduced dimensions
- Soft matter and physics–biology interface
The first theme encompasses both experimental and theoretical studies of systems with strong electronic correlations, often exhibiting remarkable properties and unconventional electronic states such as superconductivity, magnetism, or metal-insulator transitions.
The second theme includes a wide range of activities related to nanoscience, explored from the perspective of fundamental properties when an object's dimensions become comparable to key characteristic lengths (coherence length, mean free path, etc.).
The third theme expands the concept of “soft matter” to include biological systems. Topics range from complex systems to living tissues, from liquid crystals to foams, including polymers and granular materials. These studies lie at the interface between physics, chemistry, and biology.
The research work will be conducted within the MATRIX team of the Laboratoire de Physique des Solides (CNRS–UMR 8502). This PhD project is funded by the ANR project "2Rods."

Contraintes et risques

no risks