Self organization of gold nanoparticles into 2D superlattice through π-π interacton

Gold nanoparticle protected by alkylthiols with pyrene moieties was prepared and characterized by H-1 NMR, UV-vis, and elemental analysis. TEM image shows that these nanoparticles possess a narrow size distribution and 2D superlattice structures. In comparison with those nanoparticles protected by alkylthiols prepared under the same experimental condition, these superlattice structures may be attributed to the pi-pi interaction of the terminal pyrene moieties adsorbed onto the surface of gold nanoparticle. This may provide a convenient method to obtain 2D superlattice other than tedious size-selective precipitation.