Synthesis of spherical Y2O3:Er emitting particles with variable radial composition by controlled double-jet precipitation of layered precursors

Abstract

Spherical (Y0.98Er0.02)2(OH)5(NO3)·xH2O particles were synthesized by controlled double-jet precipitation, with a “core” of pure layered yttrium hydroxide nitrate, and a “shell” of co-precipitated yttrium-erbium layered hydroxide nitrates. With an increase in precipitation pH from 7 to 9.5, the size of layered “building units” decreases and the architecture of their assemblies changes from flower-like through network-like spherical to irregular agglomerates. From there, spherical particles gradually increase their diameter due to the continuous uniform growth of curved layered sheets on their surface. It was established that such growth behavior and network-like architecture of spherical particles was retained even when yttrium was replaced by erbium ions in the layered host lattice during the formation of an Er-enriched “shell”. Analysis of SEM, EDS, XPS, photoluminescence spectra and concentration quenching effects of heat-treated Y2O3:Er (2 at.%) particles indicate that the radial distribution of erbium in particles is most controllable in a narrow pH range of co-precipitation of layered precursors (pH 8). Вy widely varying the elemental composition of “building units” during co-precipitation, one can simultaneously finely control the composition of layered hydroxides in the radial direction of the spherical particles and grow multicomponent “multi-shell” powders with desired properties.