Controlled assembly of gold nanorods using tetrahydrofuran

Abstract

One dimensional gold nanostructure is one of the most studied colloidal nanostructures due to its unique optical properties and promising applications. Compared with the study of isolated Au nanorods (AuNRs), researches on the controlled assembly of AuNRs in predictable structures and consequent coupling-induced wealthy changes in optical spectra remain challenging at present. In this paper, we present an effective method for assembling AuNRs in side-by-side and end-to-end modes through simply adding water-soluble organic solvents (such as tetrahydrofuran and 3-mercaptopropionic) to the as-prepared AuNRs colloid. These two assembly modes are controlled by the concentration of organic solvent. The longitudinal surface plasma resonance of AuNRs shows great coupling effect for these two assembly modes, blue-shifting during the side-by-side assembling and red-shifting with end-to-end assembling.