Functionalized gold nanoparticles self-assemblies with efficient nonlinear optical properties

Satellite-patterns aggregate structures of gold nanoparticles were fabricated by the inducing π-π stacking interactions. The self-assembly process of satellite-patterns was tuned by the controlling ligand exchange on the surface of spherical gold nanoparticles, which provide a novel concept and an efficient method for controlling self-ass embly of gold nanoparticles. With increasing the porphyrin alkanethiol ratio (r) of gold nanoparticles, the self-assembly induces to form the larger satellite-structures. The study indicates that exchange proces s of tetra-n-octylammonium bromide molecules and porphyrin alkanethiol molecules results in the formation of satellite-pattern structures with topological features. Nonlinear optical properties of porphyrin alkanethiol capped gold nanoparticles of toluene solution were measured using the Z-scan technique, and its third-order nonlinear optical susceptibility ( _X ⁽³⁾) is calculated as 0.9×10 ^-13 esu, presented the third-order nonlinear optical properties. The well-ordered assembly of gold nanoparticles exhibits controlled the third-order nonlinear optical properties, which can be enhanced with the increasing of the porphyrin alkanethiol ratio in systems.