Transparent nanostructured RE3+ doped materials

Abstract

At present, there is an increasing interest in rare-earth (RE) doped low-phonon energy nano-materials due to their promising applications in light-emitting devices, biological labelling and imaging, up-conversion (UC) lasers, high density memories, among others. In particular, RE doped oxyfluoride nano-glass-ceramics (nGCs) have attracted attention due to the mechanical and chemical properties of oxide glasses and the lower phonon energies encountered in fluorides, which means that non-radiative quenching of emission is limited and therefore higher efficiencies can be reached. Thus, the nGCs present a high degree of transparency, due to the small nanocrystals (NCs) being dispersed in a transparent matrix (e.g. silica). In addition, energy transfer (ET) processes between neighboring RE ions are favored for the shortening of their interionic distances in the precipitated NCs. In this sense, the distribution of the optically active RE ions into the fluoride environment is of particular interest in view of the luminescent properties. By an adequate selection of RE dopant ions, colored controlled emission, or even, white light can be achieved. Therefore, the aim of this investigation work is the development and characterization of RE doped nGCs and/or nanoparticles synthesized by different methods, that yield quality emitted colors taking advantage of different ET processes that take place in the studied materials. It should be pointed out that the stay of Dr. del-Castillo at University (UNESP) Araraquara would permit to consolidate the emerging collaboration between research groups of "Photonic Materials Lab" from UNESP and "Materials Group" from ULL, which started several months ago, in Belgium, last September. Taken into account the previous experience in preparation and characterization of luminescent nanomaterials, we propose a 2 weeks' postgraduate course (30 hours) entitled "Luminescent materials obtained by sol-gel method". (AU)