Rare-Earth-Based Phosphor Particles Synthesis through Hydothermal and Spray Pyrolysed Routes

Abstract

The synthesis of nanomaterials with controlled morphology is a subject of special interest in current trend of miniaturisation. It is already shown that "soft solution chemical processing" is superior to other synthesis techniques for the preparation of such materials. When one-dimensional nanomaterials are considered, the hydrothermal method is shown to be one of the simplest techniques for their obtaining. On the other side, processing of highly spherical three-dimensional nanostructured particles is feature of the powders obtained via spray pyrolysis process. Currently there is a great interest in synthesis of nano-phosphors, mainly due to a number of potential advantages which they posses over traditional luminescent materials. Here, we present the results related to the (Y0.75Gd0.25)2O3:Eu3+ (5at%) system synthesized by both hydrothermal and spray pyrolysis processes. Conversion of the starting nitrates mixture into desired oxide composition is performed with a help of ammonium hydrogen carbonate solution during hydrothermal treatment of precipitated mixture at 200o C/3h, while pure nitrate precursors in dispersed phase (aerosol) are thermally decomposed at 900°C within a tubular flow reactor in a spray pyrolysis process. The obtained powders are additionally thermally treated either at 600/1000o C - 3h (for those hydrothermally processed) or 1100°C – 12h (for the spray pyrolyzed ones). Comparison of the morphological, structural and functional characteristics of the powders is done based on the results of X-ray powder diffractometry, particle size analysis, scanning electron microscopy, X-ray energy dispersive spectroscopy, transmission electron microscopy and photoluminescence measurement