The Copper Ions Induced The Assembly Of Gold Nanomaterials And Their Surface Plasmon Resonance Optical Properties

Heavy metal ions pollution has threatened to human health and environment.As a sensor materials,gold nanomaterials have become a focus recently for the heavy metal ions detection.The main detection mechanism is that surface-modified Au nanoparticles may be assembled by heavy metal ions.The assembling of Au nanoparticles could result in the change of surface plasmon resonance absorption.It has aroused much more attention to gold nanomaterials for the heavy metal ions detection.Herein,the research has been done to study the assembly mechanism and surface plasmon resonance optical properties of the gold nanomaterials after being interacted with Cu²⁺ for sensor.This thesis mainly research work are as follows.?1?Preparing gold nanoshell?spherical SiO₂/Au core/shell nanocomposites?functionalized by glutathione?GSH?.According to the localized surface plasmon resonance mechanism,the functionalized gold nanoshell can interact with heavy metals ions.The chelation between gold nanoshell and GSH can affect the optical property of gold nanoshell.By studying the absorption spectra,the surface zeta potential and the hydrodynamic size of the nanoshells,it can be found that their plasma resonance absorption peaks slightly shift and the zeta potential also change.Therefore,it can be confirmed that the changes of the gold nanomaterial's optical property is caused by the interaction between Cu²⁺ and nanomaterial.?2?We prepared the rod-shaped nanomaterials?gold nanorods?and the gold nanorods were modified by the GSH.The longitudinal surface plasmon resonance peak of gold nanorods will shift after being modified by GSH,and the orientation of gold nanorods will change accordingly.Based on the size dependence and the anisotropic properties of gold nanorods,the research has been done to study the change of aggregation,orientation,optical absorption properties of gold nanorods which was induced by the presence of Cu²⁺ ions.The absorption spectra show an obvious shift of longitudinal absorption peak of gold nanorods.Particularly,under the acidic condition,the localized surface plasmon resonance of gold nanorods which have combined with Cu²⁺ ions are sensitive to the electron transfer between metals.The photothermal experiment is used to study the optical property of gold nanorod affected by Cu²⁺ ions,and the result demonstrates that the Cu²⁺ ions can reduce the photothermal efficiency of gold nanorods.In this work,the isotropic spherical gold nanoshells and anisotropic gold nanorods are chosen and studied,respectively.By comparing these two materials,the interaction between the heavy metal and gold nanomaterial can be studied.It also can be confirmed that the Cu²⁺ can affect the optical property of gold nanomaterials.