Effect of Surfactants on Shape of Gold Nanoparticles

In a binary mixture of cetyltrimethylammonium bromide (CTAB) and benzyldimethyltetradecyl ammonium chloride (BDTAC), gold nanorods with a maximum absorption of longitudinal plasmon resonance up to 1600 nm have been obtained. It has been shown that the shape of the growing nanoparticles is determined by the CTAB/BDTAC molar ratio. The optimal conditions have been found for the synthesis of homogeneous nanorods with an aspect ratio of 1 : 7 in a high yield, providing their rapid formation with subsequent slow and uniform growth. The use of a CTAB/BDTAC mixture allows preventing the change in particle shape due to recrystallization during their long-term storage, as is observed in the presence of CTAB.