Study Of The Synthesis Of Gold Nanorods With Different Aspect Ratios

Nanomaterials have a variety of special properties, such as the surface effect, quantum size effect and the small size effect, which attract a lot of attention in the field of material preparation. The morphology of gold nanomaterials includes nanospheres, nanorods, nanoflakes, nanocubes, etc. Meanwhile, gold nanorods, which can absorb and scatter the incident light from transverse and longitudinal directions, show two plasmon resonance peaks in both directions. As the increase of aspect ratio, longitudinal plasmon resonance peak of gold nanorods has a redshift, which permits a wide application in chemistry, biology, medicine and other fields. Therefore, the current study on the synthesis of gold nanorods with different aspect ratios in a large scale is necessary. A modified seed-mediated method was mainly used to synthesize gold nanorods in this paper.The main content of this paper is organized as follows:1. During the process of experiments, cetyltrimethyl ammonium bromide (CTAB) was used as a single surfactant, and gold nanorods with the longitudinal plasmon resonance peak varying from 600 nm to 800 nm were obtained. Meanwhile, different content of CTBA, seeded solution, and silver nitrate solution were introduced into precursor to investigate the aspect ratio of gold nanorods. And gold nanorods with special aspect ratios (<=4) are synthesized.2. During the process of experiments, CTAB and sodium oleate (NaOL) were used as dual surfactants, and gold nanorods with longitudinal plasmon resonance peak varying from 800 nm to 1200 nm were obtained. At the same time, the effect of reagents, such as NaOL, seeded solution and silver nitrate solution, etc., were also discussed. Gold nanorods with perfect morphology and high yield were prepared. In this case, gold nanorods with special aspect ratios (>=4) are synthesized.3. The microwave-synthesis method is applied to prepare gold nanorods with adjustable aspect ratios, and it can greatly accelerate the synthesis of gold nanorods. In this method, we also added CTAB as a single surfactant. Furthermore, the effects of CTAB, seeded solution, silver nitrate solution and the heating temperature were also discussed.