One-dimensional Rare Earth Luminesent Materials: Synthesis, Characterization And Properties

One-dimensional （1D） nanostructures have attracted considerable interest due to theirunique optical, electrical, mechanical, and thermal properties. Generally, the chemical andphysical properties of inorganic micro-/nanostructures are related fundamentally to theirchemical composition, dimensionality, size, phase, surface chemistry and shape. Preciselycontrol the growth of materials, which is meaningful to tune their chemical and physicalproperties as desired, revealing the underlying fundamental theories and principles andrealizing the design of functional materials. Rare earth compounds have intensive potential invarious fields, such as optics, biology analysis and so on. In this dissertation, well definedone-dimensional La（OH）₃:Ln³⁺and NaYF₄:Ln³⁺have been successfully synthesized usingcomposite-hydroxide and molten-salten method respectively. Valuable explorations have beencarried out on the new synthetic strategies as well as controlled morphologies, formationmechanisms and luminescence properties. The main contents can be summarized as follows:One-dimensional La（OH）₃:Ln³⁺（Ln=Yb, Er, Tm, Ho） nanostructures with well-definedmorphology have been successfully synthesized by a mild hydrothermal route in the presenceof molten composite-hydroxide （NaOH/KOH）. The morphology evolution process andgovering factors have been well investigated. La₂O₃:Ln³⁺nanostructures with retainedstrip-like shape were achieved by a subsequent annealing process.Due to the well-definedmorpholog and excellent luminescenct properties, it is expected that as-doped metal fluoridematerials provide the basis for potential application for many functional devices in opticaldevices, slid-state lasers, telecommucation and sensors.we presented a simple one-pot molten salt route for the synthesis of highly crystallinehexagonal-phased NaYF₄nanotubes and nanorods for the first time. The formationmechanism and the shape evolution were well discussed, which is beneficial to the study of1D nanostructure. Interestingly, the evolution process from nanotubes to nanorods structurescan be simply modulated by altering the reaction time. The as-prepared NaYF₄:Ln³⁺nanotubes and nanorods exhibit multicolor UC luminescent emissions by altering theconcentrations of lanthanide activators and sensitizer. The development of molten saltreaction routes may open up the new opportunities in the fabrication of high quality inorganicnanocrystals especially the rare earth fluoride system. Because of the high yield and the absence of the sophisticated experimental process or harmful surfactant, this strategy couldhave a large impact on the technical applications.