A single-step synthesis of gold nanochains using an amino acid as a capping agent and characterization of their optical properties

We demonstrated a simple single-step synthesis of gold nanochains by reducing aqueous chloroaurate ions (AuCl4-) with sodiumborohydride (NaBH4) in the presence of an amino acid (glutamic acid and histidine) as a stabilizer. The structure and optical properties of gold nanochains and nanowires were characterized by transmission electron microscopy, UV -visible spectroscopy, infrared spectroscopy and femtosecond z-scan measurements. The results suggested that the gold nanochains and nanowires were formed via the nanospheres fusing into one another by an oriented attachment mechanism through dipole -dipole interactions. The z-scan measurements on Au nanowires showed a transition from saturable absorption to reverse saturable absorption as the pump intensity increased.