Study On The Synthesis And Photothermal Effect Of Noble Metal Nanostructures

Due to their optical, electronic, catalysis, sensing and some other unique properties, the noble metal nanomaterials has been one of hot research topic in nano-science. As it is known that the morphology of nanostructures is one of the most important parameters in adjusting the properties of nanostructures, growth control of nanostructures made increasing possibility on the functionality and selectivity of applications in the field of nanotechnology. With a large number of synthesis strategies for shape controlled nanocrystals, their nucleation and growth are determined at the atomic lever resulting in anisotropic growth and forming well-defined nanoparticles. These nanoparticles show distinctive optical properties known as localized surface plasmon resonance(LSPR), which has potential applications in chemical sensing and photothermal therapy. The main research and results can be detailed as follows:1. Synthesis of silver nanostructuresA solvothermal method was applied to prepared silver nanostructures, in which silver nitrate regards(Ag NO3) as precursor, and polyvinylpyrrolidone(PVP) acts as surfactant. A variety of morphology nanomaterials were synthesized, including silver nanowires, nanoplates and nanocubes, by adjusting reaction condition and experimental parameter. It is found that the uniform nanowires would be formed using PVP with high degree of polymerization. The morphology of nanoplates was effected by the molar ratio between PVP and Ag NO3. And Cl ions, acting as etching agent, played an essential role in the formation of nanocubes.2. Hollow gold nanostructuresHollow gold nanostructures(including gold nanotubes, nanorings and nanoboxes) were synthesized by galvanic replacement reaction between silver nanostructures and chloroauric acid(HAu Cl4). Silver nanostructures were used as sacrificed templates, thus the frame of gold products was similar to that of silver nanostructures. The microstructure and optical properties of products were characterized by transmission electron microscopy(TEM), scanning electron microscopy(SEM) and UV-Vis-NIR spectrum. Growth mechanism of gold hollow nanostructures was discussed by changing experimental parameters. It is found that the morphology of hollow gold nanostructures depends on that of silver templates and the amount of HAu Cl4.3. Photothermal conversion and stability of noble metal nanostructuresThe LSPR of the noble metal nanostructures can be tuned in the NIR region. Under thecorresponding NIR laser(808nm, 980nm) irradiation, the temperature of as-obtained nanostructures colloid(1m L) increase obviously with time. The stability of noble metal nanostructures under laser irradiation was also investigated by UV-Vis-NIR spectrum and TEM measurements.