Preparation of gold nanorods with different aspect ratio and the optical response to solution refractive index

Abstract

In this paper, we report that gold nanorods with different aspect ratios are controllably synthesised by a facile modified seed-mediated growth procedure. The growth rate of gold nanorods is lowered by adding H2SO4, and the yield of gold nanorods is improved. Increasing the concentration of AgNO3 yields gold nanorods with different aspect ratios that differed from 1.83 to 5.04. To prevent aggregation of cetyltrimethylammonium bromide (CTAB)-capped gold nanorods and investigate the sensitivity to the solution refractive index, surface modification is carried out. After assembling poly (sodium-p-styrensulfonate) onto the surface of gold nanorods, the samples can disperse well in water and dimethyl sulfoxide. The localised surface plasmon resonance (LSPR) wavelength of the as-prepared gold nanorods redshifts with increasing the refractive index of the solvent and a good linear relationship between LSPR peaks and refractive index is achieved.