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M.-A. Néouze, M. Kronstein, M. Czakler, M. Litschauer, H. Peterlik:
"Luminescent Ionic Nanoparticle Networks: Hierarchical Ordering from Ligand Forced Self - assembly";
Poster: MRS Spring Meeting 2012, San Francisco; 2012-04-09 - 2012-04-13; in: "MRS Spring Meeting 2012 - Program & Exhibit Guide", (2012), CC6.17.

Recently we published the synthesis of new hybrid materials, Ionic Silica Nanoparticle Networks (ISNN), made of silica nanoparticles covalently connected by organic bridging ligands containing imidazolium units owing to a "click chemistry-like" reaction.
The photoluminescence experiments performed on these ISNN hybrid materials showed an emission around 410 nm, whereas the used precursors are not luminescent. The quantum yields measured, up to 26%, are extremely promising for photoluminescence applications of the ISNN. Among other techniques small-angle X-ray scattering (SAXS) experiments were carried out to get a better picture of the network extension. The SAXS experiments revealed a clear short-range order in ISNN materials. This short-range order is dependent on the rigidity of the bridging ligand. Moreover the shift towards longer wavelengths of the luminescence emission maximum, obtained when varying the aromatic ring content of the bridging ligand, suggested the existence of strong π-π stacking in the hybrid material. Experiments revealed a stronger luminescence in those samples exhibiting the higher extent of short-range order in SAXS. Thus the ordering of the hybrid material seems to be directly linked to the photoluminescence features of the material.