Synthesis of different size amino acid capped nanoparticles varying the external conditions

Abstract

Herein we systematically investigated the effect of different temperatures, pH, and pressure (hydrothermal method) on the size of the aromatic amino acid-functionalized gold nanoparticles where amino acids act as a reducing agent as well as capping agent. We found that temperature plays a key role in the size tunability during the nanoparticle synthesis. Tryptophan and phenylalanine functionalized nanoparticles have the excellent ability to tune the size of the nanoparticle whereas the size of the tyrosine functionalized nanoparticle is independent of temperature. Further, the formation of gold nanocluster was also observed during the hydrothermal method. Surprisingly, we found that except phenylalanine tryptophan and tyrosine can form the gold nanoclusters with excellent luminescent properties.