Molecular linker-mediated self-assembly of gold nanoparticles: understanding and controlling the dynamics

This study sheds light on the mechanism and dynamics of self-assembly of gold nanoparticles (AuNPs) using molecular linkers such as aminothiols. An experimental model is established that enables a fine control and prediction of both assembly rate and degree. Furthermore, we have found that under certain conditions, the increase in the molar ratio of linker/AuNPs beyond a certain threshold unexpectedly and dramatically slows down the assembly rate by charge reversal of the surface of nanoparticles. As a result, the assembly rate can be easily tuned to reach a maximum growth within seconds to several days. The decrease of the same molar ratio (linker/AuNPs) below a certain value leads to self-termination of the reaction at different phases of the assembly process, thus providing nanoparticles chains of different length. This work introduces new handles for a rational design of novel self-assembled architectures in a very time-effective manner and contributes to the understanding of the effect of the assembly morphology on the optical properties of gold nanoparticles.