Study On Photothermal Conversion,Assembly And Surface Coating Of Gold Nanorods

In recent years, with the development of nanometer science, noble metal nanomaterials exhibitwide potentials in various technical fields due to their unique or improved properties. For the case offabrication, great efforts have been made on the synthesis of nanostructures with well-defined shapesthrough improving or developing methods. In applied sciences, the key problems on the application ofnanomaterials are focused on the building ordered assembly and functional units. In this work, basedon the research of surface plasma resonance (SPR) of gold nanorods, we carried out the controllableassembly of gold nanorods and realized the tunable optical absorption property in a large NIR spectralregion. Surface coating with SiO2provides an effective way for dealing the toxicity of and biologicalcompatibility of gold nanorods covered with CTAB.The main content of this thesis includes the following parts:1. Using a “seed” method, gold nanorods with SPR at810nm and1060nm were prepared. Then,we carried out the experiment on the photo-thermal effect of gold nanorods under the irradiation of808nm and1064nm lasers. An obvious photo-thermal effect was obtained. Under low power laserradiation, photo-thermal efficiency decrease with increasing the irradiating time. Under a high powerlaser irradiation, gold nanorods colloid quickly boiled. Images observations indicated that the aspectratio of gold nanorods decreased and finally changed into spherical particles, which is accordant withthe disappearance of the longitudinal resonance peak.2. We carried out surface functionalization for gold nanorods by designing different experiments.A facile way was developed for the side-by-side assembly of gold nanorods using PEGdithiol(SH-PEG-SH). The end-to-end assembly of the AuNRs proceeded with addition of MPA to thecolloids of isolated AuNRs. The samples were characterized by TEM and UV-Vis-NIR spectroscopy,and the results were discussed.3. Cetyltrimethylammonium bromide (CTAB) covered around the gold nanorods was strongbiologic toxicity, it is difficult to combine systems with biomolecules. This limits greatly the possibleapplications of gold nanorods. We herein carried out the surface coating gold nanorods with silica intoAu@SiO2core-shell nanostructure. The changes in the optical properties of gold nanorods before andafter coating, and the morphology of coating results were compared by optical measurements andTEM observations.