PhD subjects

Graphene as a constituent of graphite was close to us for almost 500 years. However, it is only in 2005 that A. Geim and K. Novoselov (Nobel Prize in 2010) reported for the first time the obtaining of a nanostructure composed by a single layer of carbon atom. The exceptional electronic properties of graphene make it a very promising material for applications in electronic and renewable energies.

For many applications, one should be able to modify and control precisely the electronic properties of graphene. In this context, we propose to synthesize chemically graphene nanoparticles and study their absorption and photoluminescence properties. We will focus on their solubilty in water in order to study potential applications in biology. This project will be developed in collaboration with Physicists so the candidate will work in a multidisciplinary environment.

This thesis project aims to exfoliate new nanostructured architectures based on two-dimensional inorganic phases. These nanostructures will be designed for filtration devices and tested using our microfluidic platform. The target application is water purification and the selective separation of metal ions. The doctoral student will interact with chemists, physicists and electrochemists in a real multidisciplinary environment, on a fundamental research subject directly connected to application needs. Thus, during his thesis, the student will be exposed to a multidisciplinary environment and brought to carry out experiments in various fields such as inorganic chemistry, physical chemistry, micro / nano-fabrication and nano-characterization methods. In In this context, this project should potentially lead to significant societal benefits.

For the realization of the latter, he will have access to a very wide and varied range of equipment ranging from optical microscopes to the latest generation synchrotron (ESRF), including field effect or electron microscopes and galvanostats.

This thesis is therefore an excellent opportunity for professional growth, both in terms of your knowledge and your skills.

Perovskite solar cells (PSCs) have become a trending technology in photovoltaic research due to a rapid increase in efficiency in recent years. In 2020, a record efficiency of 25.5% close from Shockley-Queisser theoretical limit of 30% was reported. Tandem solar cells offer an alternative to go beyond but stability still remains an issue.

In our project, we will bring together our complementary expertise in molecular and macromolecular syntheses, thin film morphology tuning and cell device engineering to improve the stability of highly efficient inverted perovskite cells using new electron transport layers (ETL) with high electron mobility and high stability. We will design and synthesize new n-type fullerene free semiconductors. Introduction of cross-linkable groups will lead to stabilized ETLs by thermally-induced cross-linking after film formation. The efficiency and stability of these ETLs will be finally evaluated through their incorporation in tandem configuration.

Despite their many positive impacts, PV panels production face threat of sustainability of growth in terms of raw materials, energy, and environment. The PV industry is very dependent on critical raw materials and this dependence is getting worse as the production and consumption of solar panels are increasing considerably.

The main goal of this project is to develop the next generation of transparent/non-transparent conductive layers based on non- critical raw materials. These layers will be used as contact, interconnections in innovative solar panels. Guiding principle of this project is to construct competitive high quality/low-cost conductive line to replace silver contact. Due to these outstanding properties, Graphene could play an essential role in replacing critical material and enhancing electrical conductivity. This Ph-D project will be devoted to the development of low and high temperature conductive graphene inks. These inks will be designed for serigraphy, inkjet, or any suitable low-cost printing deposition techniques to print contact and interconnection. i) Inks properties in terms of composition, viscosity will be tuned. ii) The behavior of printed conductive ink will be investigated after being exposed to different stress (mechanical, temperature, moisture, electrical, light, oxygen….). iii) Finally the focus will be on conductivity characterization as a function of electrode morphology (thickness, porosity, …) and mechanical resistance. The overall aim is to optimize conductivity, mechanical resistance, and durability and finally incorporate these improvement in perovskite solar cells.

In this project, we propose to valorize the critical metals lost, as they are not currently retrieved, when recycling printed circuit boards. The focus will be on the key step of sorting the electronic components resulting from the dismantling of these boards. This project involves the study of a multispectral sorting prototype combined with the development of software for recognition by Artificial Intelligence.

This thesis is financed by the REVIWEEE and CYCLAMET projects of the PEPR (priority research programs and equipment) 'Recyclability, recycling and reincorporation of recycled materials' of the 4th Future Investment Program of the French government. During his or her Ph.D. thesis work, the student will be exposed to an international and multidisciplinary environment, with in particular the realization of experimental developments in various fields such as mechatronics, spectroscopy, physical chemistry, characterization and modelling in strength of materials, instrumentation; but also, to work in programming and algorithms with the Borelli Centre of the ENS Paris-Saclay, partner of the project (co-direction of the thesis).

This thesis is therefore an excellent opportunity for professional growth, both from the point of view of your knowledge, and your know-how and life skills in an international multi-cultural environment: the CEA group is bi-located in Saclay and Singapore. It will also be an opportunity to use your knowledge in a practical way to achieve a goal with a potentially high environmental impact.

To meet the increasing energy demand and diversify energy resources, fuel cells emerge as a promising solution. This Ph.D work aims to contribute to the development of Proton Exchange Membrane Fuel Cells (PEMFCs), with a specific focus on bipolar plates (BPs) which ensure gas distribution and current collection. The first objectives are to design and manufacture stainless steel BPs using 3D printing (SLM - Selective Laser Melting) and to develop organic and inorganic anticorrosion coatings. Multiple channel architectures will be designed and characterized, including in-situ assessments with membrane-electrode assemblies (MEAs). Coatings will also be characterized, particularly in terms of their corrosion resistance through polarization methods. In the second phase, the aim is to integrate the optimized BPs with MEAs and thoroughly study the performance of PEMFCs using electrochemical techniques to gain fundamental insights into the mechanisms that limit PEMFCs performance.