SEED MEDIATED GROWTH CONTROLLED GOLD NANORODS: SYNTHESIS AND CHARACTERIZATION

Gold nanospherical and nanorods in aqueous dispersion were synthesized using seed-mediated growth method. The gold nanoparticles were characterized using X-ray diffraction, transmission electron microscopy (TEM), and UV-Vis absorption spectroscopy. It showed that the diameter of the prepared Au nanospheres can be controlled by several parameters such as the amount and the type of seed. It was also found that the absorption peak shifted to lower wavelengths from 539 to 525 nm and the width of the peak decreased when the amount of the seed prepared using sodium citrate increase from 0.025 to 1 mL. In other words, the size of the gold nanospheres decreases when the amount of the seed increase, while the peak remains at 527 nm when the amount of the seed prepared, using cetyltrimethlyammonium bromide (CTAB) solution, increase. The emergence of another peak at 650 nm, which indicates the presence of the nanorods, appears after changing CTAB concentration and adding silver nitrate in the growth solution. The size of the gold nanospheres decrease when the concentration of the CTAB increase. The aspect ratio of gold nanorods can be controlled by adding different amount of silver nitrate and using seed prepared by CTAB solution.