The processing of optically active functional hierarchical nanoparticles

Abstract

Global climate changes and the aroused environmentally-energy problems categorically moved the research efforts towards programmed processing of a novel class of hierarchical materials having well defined phase, compositional and morphological features. The synthesis based on the principles of the molecular design and integrative chemistry which includes the innovative aerosol and hydro(solvo)thermal nanotechnology routes, the building block assembling and hybridization, represent intelligent platform for the creation of advanced functional materials. Due to exceptional optical properties and a diverse application in electronics, optoelectronics, energy conversion/storage and biomedicine, the examples from some wide band gap oxides for light harvesting and photocatalytic applications as well as both down and up-conversion energy-saving luminescent materials for photonic and biological applications are considered. With the help of various analyzing techniques like XRPD (X-ray powder diffraction), field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), analytical and high resolution transmission electron microscopy (TEM, HR-TEM), selected area electron diffraction (SAED), scanning tunneling electron microscopy (STEM), Fourier transform infrared (FTIR) and Raman spectroscopy, photocatalytic and fluorescence measurements, the opportunities of the aerosol and hydro(solvo)thermal routes for the synthesis of novel hierarchically and hybrid assembled structures and nanocomposites are reviewed highlighting the recent research activities realized in the Institute of Technical Sciences of SASA, Belgrade, Serbia and University Carlos III, Madrid, Spain. The morphological, structural and functional aspects of the following systems: ZnO, TiO2, Y2O3:Eu,Yb/Er/T/Hm, Y2O3:Eu@Ag, (Y1−xGdx)2O3:Eu, (NaYF4:Yb/Er)@EDTA/PEG/PVP, are discussed from the state-of-the art and literature contexts. Controlled growth of 1D and 3D hierarchical structures based on the single-source processing methodology in combination with the homogeneous precipitation of optically active intermediate precursor are especially stressed for the case of yttria based phosphor particles and phase-dependent luminescence efficiency. The obtained results offer possible routes for the synthesis of hierarchically structured nanomaterials with tunable structure, morphology and optical properties.