Considerable progress has recently been made in the synthesis of inorganic particles down to a few nanometers in size. The first syntheses to achieve nanoparticle sizes with dispersions down to 5% in size date back to 1993, and were obtained with semiconductor nanoparticles. Since then, this type of synthesis has been extended to many other crystalline nanomaterials. It is now possible to precisely control the shape (sphere, rod, wafer), composition, crystalline structure and surface chemistry of inorganic nanoparticles. These inorganic nanoparticles, made up of a few hundred to a few thousand atoms, have physical or chemical properties not found in individual molecules or in bulk material.
This seminar presented advances in the synthesis and new properties of these nanoparticles through some of the results we have obtained in the Quantum Nanomaterials team at ESPCI. In particular, we have shown that it is now possible to synthesize atomically flat semiconductor nanoplatelets in solution, with a thickness controlled to the nearest atom. These nanoplatelets fluoresce and emit colors of unprecedented purity. We have also discussed the possibility of synthesizing nanoparticles with a core/shell geometry in solution, on both spherical cores and nanoplatelets. These core/shell structures have greatly enhanced fluorescence properties. Finally, we present a brief overview of possible applications for semiconductor nanoparticles, ranging from in vivo imaging in biology to optoelectronic components such as photovoltaic cells and light-emitting diodes.
