Description du sujet de thèse

The generation of electricity from waste heat by thermoelectric devices is emerging as a promising alternative energy source for the future. The study of thermoelectric materials has been growing strongly over the past decade in the international scientific community, with the aim of designing new materials with high performances. The challenge is to synthesize a material in which the electrical and thermal properties are decoupled. In short, how can we develop an electrical conductor that conducts very little heat?
In this context, numerous studies have demonstrated the potential of sulfide materials for thermoelectric applications over the temperature range 300 – 700 K. Although most materials have high thermal conductivities, recent works carried out, in particular at CRISMAT laboratory, demonstrated that extremely low thermal conductivities could be achieved in copper-, bismuth- and Sn-based compounds through order/disorder phenomena and/or cationic vibrations phenomena. In particular, it appears through recent studies that the low dimensionality of the crystal structures induced by the presence of weak bonds in connection with the existence of the lone pair of electrons of Bi3+ or Sn2+ favors a strong diffusion of phonons and thus intrinsically low lattice thermal conductivities.
The objective of the PhD thesis will be to study different families of compounds with specific structural features which can generate high thermoelectric performances.
In addition to the chemical characterization of powders and densified ceramics (density, X-ray diffraction, SEM and TEM microscopy, thermal analyses, etc.), the PhD student will endeavor to understand the physical properties of these materials, in particular the influence of crystal structures and microstructures on electrical and thermal transport properties.
Applicants should have a strong background in materials science, solid-state chemistry and physics. Experience in materials processing, crystal structure analysis and transport properties would be an advantage.

Contexte de travail

The CRISMAT laboratory is a joint CNRS, ENSICAEN and Université Normandie unit with around one hundred members.
The candidate will join Emmanuel Guilmeau's research group. The thesis will take place at the CRISMAT Laboratory and will be supervised by Emmanuel Guilmeau.
It will start no earlier than 1st September 2025 and no later than 1st October 2025 for a period of 3 years.
This job offer is subject to funding being obtained and to applications being reviewed by the Human Resources Department.

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

This job offer is subject to funding being obtained and to applications being reviewed by the Human Resources Department.