Synthesis and characterization of lanthanide doped nanophosphors

Abstract

In this thesis, a series of lanthanide doped nanoparticles were synthesized by microemulsion technique for the first time. They included Eu:Y2O3 (red-emitting), Tb:Y2O3 (green-emitting), and Tm:Y2O3 (blue-emitting) nanophosphors for field emission display (FED) application as well as upconverting nanophosphors Pr:Y2O3 and Er:Y2O3. Various characteristics of lanthanide-doped nanoparticles were extensively investigated by thermogravimetry (TG), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), and photoluminescence instruments (PL). Meanwhile, we investigated the effect of different factors such as the concentration of dopants, calcine temperatures, doping hosts as well as codopants on the luminescent properties of the lanthanide doped nanoparticles. Microemulsion technique has been proved to be a powerful synthesis method to obtain lanthanide doped nanophosphors with good optical properties. Both Eu:Y2O3 and Tm:Y2O3 nanophosphors prepared in microemulsions had higher quenching concentrations compared to those prepared by conventional synthesis method. Bi3+ is a favorable codopant to improve green emission and color purity of Tb:Y2O3. Tb3+ has enhanced intensity of emission in La2O3. This work also provided fundamental experimental databases of upconverting nanophosphors Pr:Y2O3 and Er:Y2O3.