[nanoPost] Synthesis of inorganic nanoparticles with controlled shape

University France 

The use of nanomaterials for optics is a rapidly growing field with tremendous potential. For example, nanoscale metal or semi-conductor particles in the size range 1-10nm, as compared to their bulk counterpart, exhibit unique properties different from the bulk state (size quantization, unusual fluorescence or absorption).

The group is involved in the synthesis of inorganic nanoparticles with controlled shape (isotropic or anisotropic), size and composition, as well as in their surface modifications using inorganic and/or organic parts in order to design very specific properties (absorption properties, dispersion in very different organic solvents).

A large range of nanoparticles, including oxides (zirconia, titania, silica, boehmite, iron oxides), sulfures (CdS, ZnS), metals (Ag, Pt, Au) and their combinations (core-shell systems) were prepared. Incorporation of nanoparticles in hybrid organic-inorganic media leads to very stable materials with required properties (high refractive index, dynamic colour effect).

Materials for luminescence: The group is involved in projects for both inorganic and organic luminescence for the preparation of LED or chemical and biosensors. Inorganic luminescent materials are usually prepared using oxide matrices which are doped with rare earth. Their approach consists of using molecular heterometallic species as single source precursors to doped oxides. For example Er4TiO(OPri)14 was used as starting materials combined with Ti(OPri)4 for the preparation of Er doped TiO2 films and the same approach can be transferred to other systems such as Y2O3:Eu3+. This should allow the preparation of very stable systems preventing from aggregation of the rare earth during thermal annealing.

The group has developed molecular engineering on macrocycles for the preparation of hybrid materials with specific optical properties (OPL). The synthesis of luminescent probes combining thiacalixarenes with rare earth, and their incorporation in inorganic matrices using the sol-gel process is investigated for the preparation of chemical and biosensors. Indeed, such macrocycles in cone conformation can act as molecular receptors with high selectivity depending on the functional groups grafted on the calixarene core.