Hydrothermal Synthesis And Properties Of Strontium Fluoride And Antimony Telluride Nanomaterials

Recently, functional nano-materials have been widely applied in the field of optical, electrical, thermal, magnetic, catalytic, photoelectric and thermoelectric due to their excellent physical and chemical characteristics, which have been played a pivotal role in the technology developing and energy issues. Among them, strontium fluoride has been promoted the research of optical materials and instruments in the optical aspect owing to its unique structure and property; and in the thermoelectric aspects, the moderate thermoelectric conversion efficiency of telluride antimony has provided a reliable theoretical basis for the development and utilization of green energy. As it is known, there are affinitive relationships between the structure, shape and property so how to achieve the controlled synthesis of materials have attracted wide attention. To date, many physical and chemical synthesis methods have been applied to the preparation of micro/nanomaterials in various fields, such as gas/liquid phase deposition method, ball milling, microwave method and hydrothermal method. However, hydrothermal method has been welcomed by scientists, with the advantages of low-wasting, easy operation, high yield and so on. Here, hierarchical SrF2and SrF2:Ln3+(Ln=Er, Nd, Yb, Eu, Tb) micro/nanocomposite architectures, and pure Sb2Te3nanoplates were synthesized using the simple hydrothermal method in this work. We also studied the composition, structure, morphology optical and thermoelectrical properties of the synthesized materials, respectively. At the same time, the sampels of the growth mechanism were also discussed. The main contents are as follows:1. Well-defined SrF2and SrF2:Ln3+(Ln=Er, Nd, Yb, Eu, Tb) hierarchical microspheres composed of densely aligned nanoplates have been prepared by a simple one-pot hydrothermal method in the presence of ethylenediamine tetraacetic acid disodium salt (Na2EDTA), and strontium nitrate (Sr(NO3)2), sodium flioroborate (NaBF4) were used as strontium source and the source of fluorine respectively. To obtain a better understanding of the formation mechanism of the hierarchical SrF2microspheres, the reaction time, temperature, chelating reagent and fluorine source were discussed and the whole evolution process was illustrated. The luminescence properties of5%Ln3+(Ln=Er, Nd, Yb, Eu, Tb)-doped SrF2micro/nanostructures were also investigated.2. Highly uniform and impurity-free Sb2Te3hexagonal nanoplates were synthesized at180℃in the presence of Sb2O3as antimony source, Na2TeO3as tellurium source, and the mixture composed of diethylenetriamine (DETA) and deionized water (H2O) as solvent. The samples were only18～20nm thickness and150～200nm side length. And its thermoelectric properties was studied, the results showed that the sample had a high Seebeck coefficient and low thermal conductivity which had the advantage of prospects in the field of green energy development.