Fabrication And Photoluminescent Properties Of Rare-Earth Ions Doped Low-Dimensional Nanosized Luminescent Materials

Low-dimensional nanostructured materials have sparked a worldwide interest due to their unique electronic, optical, and mechanical properties and their potential applications in nanodevices and functional materials. It is well-known that the properties of low-dimensional nanomaterials are sensitively dependent on their structure, dimension, shape and size. Therefore, the most important problem faced by the scientists is how to fabricate nanostructures with the controllable structure, dimension, shape and size. Recently, the biomolecule-assisted-synthesis method has become one of the promising methods for preparation of various nanomaterials, whose special structures and fascinating self-assembling functions allow them to serve as templates for the design and preparation of complicated structures. In addition, rare earth luminescent materials have important applications in high-resolution displays, integrated optical systems, solid lasers, medical diagnostics and biological analysis due to their properties of high brightness, long afterglow, adjustable wavelength scale and non-radiation substance. Based on these considerations, we, for the first time, successfully synthesized nanostructured materials of rare earth fluorides, rare earth orthophosphates, rare earth orthovanadates and rare earth oxides by amino acids-assisted hydrothermal synthesis method. These samples were characterized by XRD, FESEM, TEM and PL in detail. The details are summarized as follows:1. Single-crystalline LaF₃:Eu³⁺ hexagonal nanoplates, YF₃:Eu³⁺ nanoparticles and ellipsoidal CeF₃:Tb³⁺ nanoparticles were firstly synthesized by hydrothermal method, using amino acid as the complexing and capping agent. It was discussed in detail that different amino acids molecules have different influences on the morthology, structure and luminescent properties of the LaF₃:Eu³⁺ nanostructured materials. All the samples have the same structure, but different morphology and luminescent properties.2. LaPO₄:Eu³⁺ nanorods, YPO₄:Eu³⁺ nanobundles and spindle-like nanostructured materials and CePO₄:Tb³⁺ nanorods were firstly synthesized by hydrothermal method, using glycine as the complexing and capping agent. The possible formation mechanism of YPO₄:Eu³⁺ nanobundles were discussed in detail.3. LaVO₄:Eu³⁺ nanoparticles and YVO₄:Eu³⁺ nanoparticles were synthesized by hydrothermal method, using glycine as the complexing and capping agent.4. La₂O₂CO₃:Eu³⁺ nanoparticles, flower-like Y₂O₃:Eu³⁺ nanostructured materials and spherical CeO₂ nanoparticles were synthesized by hydrothermal method, using glycine as the complexing and capping agent. The results of La₂O₂CO₃:Eu³⁺ nanoparticles and flower-like Y₂O₃:Eu³⁺ nanostructured materials shows that precursor and calcined samples have the same mophology, but the excitation and emission spectra of calcined samples are stronger than those of precursor.