| dc.description.abstract | With the excellent optical performance, the rare-earth-element-doped (RE-doped) nanomaterials have been widely applied in biological system and optical engineering. The understanding about effects of rare earth elements on optical properties needs to be further achieved. In the present research, a new approach has been developed to control the morphology and modify the optical performance of engineered RE-doped nanomaterials.
Experimental approaches contain synthesis, characterization, and optical and tomographic imaging investigation of nanomaterials: morphology-controlled yttrium oxide doped with erbium and ytterbium (Yv2Ov3:Er^3+,Yb^3+), hydrogen-treated aluminum yttrium oxide (Yv3Al5Ov12 or YAG) doped with cerium (YAG:Ce^3+), and oleic acid coated sodium yttrium fluoride (OA-NaYF4:Er^3+,Yb^3+).
The morphology of Yv2Ov3:Er^3+,Yb^3+ were controlled by introducing metal ions during facile hydrothermal synthesis. It was found that the negatively charged aluminum complex ions enabled the evolution of nanotubes through rolling from nanosheets. The positively charged calcium complex ions prohibited the rolling of nanosheets. For hydrogen-treated YAG:Ce^3+, the hydrogenation has been firstly used to induce the defects into the host lattice of YAG, which leads to a red-shift in the emission spectrum of YAG:Ce. This red-shift can make an improvement in warm white LED (light emitting diode). For OA-coated NaYFv4:Er^3+,Y^b3+ , they were firstly applied in lubricant. As mineral oil is a type of nonpolar oil, OA-coated NaYFv4:Er^3+,Yb^3+ NPs would be a potential excellent additives.
In fundamental investigation, three approaches and mechanisms in modifying optical performance of RE-doped nanoparticles (NPs) were studied. They are using alternative host lattice, alternative dopants and introducing defects.
Optical and tomographic imaging was used to study the effects of NPs on bio-imaging, white LED and lubricating grease. As RE-doped NPs were widely used, once engineered NPs are translocated to the food chains, they could accumulate in organisms and even cause toxicity and biomagnification. In order to investigate the effects of engineered NPs on environment, synchrotron dual-energy X-ray micro-tomography was used to study the uptake pathway, accumulation, distribution and concentration mapping of the engineered NPs in an essential component of ecosystems, the plants. | en |
