Mesoporous oxide films as nano-reactors for building photoluminescent nanostructures?

MARTINEZ RICCI, MARIA LUZ; SARA A. BILMES; DIEGO ONNA

Bled

Conferencia; Nanoapp 2017; 2017

IOS-Institute for Environmental Protection and Sensors

Luminescent materials in nanostructures are envisaged as scaffolds for the design of multifunctional devices. However, most of them are toxic for humans and involve the use of low-abundance elements with costly and environmental non-friendly mining. Here we propose the use of nanostructures made of reproducible ordered mesoporous oxides films (OMPO) containing luminescent nanoparticles as building blocks for more complex composite structures. The advantage of this approach is the reduced amount of heavy metals involved, as well as providing fixed nanoparticles in an inert matrix. The main idea of this work is to obtain efficient luminescent materials using pores in a OMPO as nano-reactors for precipitation reactions, controlling the size of nanoparticles (NPs) grown inside pores.Using each pore as a single nano-reactor, an environmentally friendly synthesis was carried out by successive immersions in solutions of the appropriate precursors. Special attention was paid to the role of solvent, precursors and pH in the nucleation and growth mechanism inside pores leading to optimized photoluminescence. This approach was successfully carried out for semiconductor (CdS and ZnS) Q-dots and YVO4:X (X= Eu; Yb:Er; Yb:Ho) nanophosphors embedded in a Silica, Zirconia or Titania matrices. Intense and tunable luminescence was achieved for Q-dots after aging and/or photoactivation, even the very low mass amounts. Nanophosphors synthesized inside pores also exhibit photoluminescence, as well as up-conversion.In addition to probing the feasibility of building complex luminescent nanostructures, in this work we discuss the mechanism of nucleation and growth of NPs inside pores and how to control of photoluminescent emission.