Missions

We have recently developed silicon@silica core-shell particles demonstrating directional scattering in the forward direction over a broad frequency range (https://hal.science/hal-03188905/). We have since discovered through simulations (https://arxiv.org/abs/2502.13338), that there are other core-shell particles that demonstrate even more intense directional scattering. The challenge is now to synthesize these particles and study their optical properties. Different synthetic techniques will be used, such as sol-gel chemistry and electroless deposition of thin shells of silver. The contract is for 15 months, renewable by 8 months (2 years total).

Activités

The objective of this study is to refine our recently published redox synthesis of silicon particles to decrease the polydispersity of the silicon cores (https://pubs.acs.org/doi/full/10.1021/acs.chemmater.4c01439). We will do this by examining the role of solvent polarity, as this has had a major impact on the monodispersity in silica. In situ characterization techniques, such as SAXS and UV-Vis spectroscopy will be used to monitor in real time silicon particle nucleation and growth. Machine learning tools will be applied to accelerate the discovery of an optimized synthetic protocol. The oxide and metallic shells will be grown using standard synthetic techniques that are well developed and published. Once the core-shell particles are produced, they will be characterized using dark-field microscopy to measure both forward and backward scattering, in collaboration with researchers in Toulouse. The forward/backward light scattering ratio will be studied as a function of core size, shell thickness and the chemical nature of the shell (ZrO2, SiO2, TiO2, Al2O3, Ag).

Compétences

For this study, a person with experience in synthetic chemistry is needed. Skills working under air-free conditions (i.e. Shlenck line, glove box) are desired. The candidate ideally has previous experience with optics (at least a basic understanding of Mie resonance) and microfluidics. The candidate should have experience in several of the following characterization techniques: electron microscopy (TEM and SEM), X-ray diffraction, UV-vis and Raman spectroscopy. A high level of scientific English, ambition and curiosity are required.

Contexte de travail

The post doctorate researcher will participate in the ERC funded project Scatter under the supervision of Dr. Glenna Drisko (https://glennadrisko.com/). She or he will be integrated into the Matériaux Fonctionnels et Photonique axis in the Laboratoire de Chimie (LCH – CNRS UMR 5182), in Lyon, France (https://www.ens-lyon.fr/CHIMIE). The post doc will benefit from the synthetic experience of the host team as well as the material fabrication and optical characterization expertise in the project consortium. The post doctorate researcher will be responsible for the synthesis of silicon cores, oxide shells and metallic shells, optical characterization of both particles suspended in solution and on a substrate. She or he will be directly involved in the work of 1 PhD students working on parallel and interconnected projects in a highly dynamic and stimulating environment.
The application will include a complete CV, a letter of motivation, and 2 of the candidate's publications. Letters of recommendation can be optionally included in a single PDF with the letter of motivation. The application should be written in English and submitted through the CNRS website. A first contact directly with Dr. Drisko is highly recommended (glenna.drisko@icmcb.cnrs.fr).

Contraintes et risques

The main risks associated with this project is handling organic solvents that demonstrate a certain degree of toxicity and flamability. Electrical equipment will be used. The characterization room is rather loud due to multiple pieces of equipment and vacuum pumps being used in parallel.