Rare-earth fluoride based luminescent nanostructures for energy conversion: pros and cons between MOCVD and solution routes

Abstract

In this project, we prepared and characterised rare-earth fluoride based luminescent thin films using the Metal-Organic Chemical Vapour Deposition process. Previously, lanthanum, gadolinium, neodymium, europium, and erbium precursors were synthesised and characterised by FT-IR spectroscopy, DSC, and TG analysis. The structure and crystallinity of the deposited films have been investigated by X-ray diffraction (XRD). The morphological properties of the films were examined by FE-SEM analysis, while the composition was determined by EDX analysis. In parallel, NPs with the same composition as the films have been synthesised via a microwave-assisted hydrothermal method and structurally and morphologically characterised by XRD and TEM, respectively. Luminescence measurements have been performed on both the doped films and NPs to compare their luminescent properties. Up-conversion emission spectroscopy was measured as a function of the laser pump power for Er-doped GdF₃ and GdOF samples. As an example, a temperature-dependent photoluminescent study has been performed to investigate the potential use of GdOF:Er 1% NPs as nanothermometer.