Superlattice of Ag nanoparticles prepared by new one-step synthetic method in aqueous phase

Self-assembled superlattice of Ag nanoparticles were prepared by a new one-step synthetic method in aqueous phase to reduce the size distribution. The Ag colloidal solution capped with the mixture of two capping molecules, sodium oleate and aromatic carboxylic acid self-organize into a 3D superlattice. The results show that when the molar ratio of aromatic carboxylic acid to sodium oleate is increased, the shape and size distribution of Ag nanoparticles are similar to those prepared by aromatic carboxylic acid alone. The 3D superlattice crystal structures are determined by the location of Ag nanoparticles in the third layer while the FCC structure is observed as it has a specific sequence and the hole is capped. The thickness of two yellow shells is equal to the interparticle distance between Ag nanoparticles while the nanoparticles of 9.3 nm is surrounded by a hexagon formed by 2.3 nm interparticle distance.