Hydrothermal synthesis of optically active fluoride particles doped with rare earth ions in the presence of ethylenediaminetetra acetic acid (EDTA)

Abstract

Fluorescent nanoparticles have an important role in biological analyzes, and in the last ten years they are successfully applied in a visualization and characterization of biological processes at the cellular and molecular level, as well as, in the development of fluorescent lamps, displays, plasma screens and protective labels. The great interest is directed towards the development and implementation of the light up - converters containing rare earth ions which have the ability of a intense luminescence. In this paper we described the process of EDTA assisted hydrothermal synthesis of rare earth doped fluorides. Different structural forms of materials were obtained by changing the time of the hydrothermal reaction. Comparison of a structure, morphology and optical properties of NaYF4:Yb3+/Er3+ powders were done based on X-ray powder diffraction analysis (XRPD), scanning and transmission electron microscopy (SEM and TEM) and through measuring of the luminescence in a visible part of spectrum. It was shown that the transformation from cubic to hexagonal phase is affected by the reaction time, while the up - conversion luminescence is dependent of the particles morphology and the crystal structure.

Keywords

• NaYF4:Yb3+/Er3+
• EDTA
• hydrothermal synthesis
• luminescence