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Unité de Formation et de Recherche de Chimie

Soutenance de l'HDR de David Portehault

Soutenance de l'Habilitation à Diriger des Recherches intitulée
"Beyond the compositional threshold of nanoparticle-based materials"

le vendredi 14 décembre à 14h, en salle 2 au Collège de France.


The design of inorganic nanoparticles relies on the knowledge from solid state chemistry for choosing the systems that will yield the desired properties. The range of inorganic solids reported and studied as nanoparticles is however strikingly narrow when compared to the solid state chemistry portfolio of bulk materials. Enlarging the collection of inorganic particles is increasingly important for three reasons. First, it can increase performances in fields like biomedicine, optics, catalysis and energy. Second, looking outside the box of common compositions can yield original properties. The third reason lies in the path followed to reach these novel nano-objects: exploration and set-up of synthetic approaches. Willingness to access original nanoparticles faces a synthetic challenge: how to reach nanoparticles of solids that originally belong to the realm of solid state chemistry and high temperatures? Alternative reaction pathways must be sought. The corresponding strategies require limiting particle growth by confinement at high temperatures or by decreasing the synthesis temperature. The latter case provides a nice playground to discover metastable solids never reported before. We present herein our contribution to the design of new inorganic nanoparticles. We first describe challenges and how they are currently addressed. We then show our achievements by spanning low temperature “chimie douce” aqueous synthesis for metal oxyhydroxides, sol-gel chemistry and processing coupled to solid state reactions for low valence oxides, molten salt synthesis for multicationic oxides and then for non-oxidic boron-based nanomaterials. These nano-objects show original properties, from sensing, thermoelectricity, charge and spin transports, photoluminescence and catalysis, which require advanced characterization of surface states, described in a following section. Finally, we outline the frame of the project and future trends we plan to explore.

Keywords: nanoparticles, nanomaterials, oxides, boron, molten salts, aqueous synthesis, inorganic materials, solid state chemistry.


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