π–π interactions mediated self-assembly of gold nanoparticles into single crystalline superlattices in solution†
The first attempt of employing π–π interactions for the self-assembly of colloidal gold nanoparticles into 3D single crystalline superlattices in solution is presented. It is demonstrated that simple capping ligand exchange with aromatic thiols leads to self-assembly of gold nanoparticles into fcc packed superlattices with well-defined facets and long-range ordering. Stimuli that can break the π–π interactions lead to disassembly of gold nanoparticles, allowing the design of reversible assembly and reconfiguration. The crystallization of gold nanoparticles is shown to be kinetically controlled by the concentration of aromatic thiols in solution, enabling efficient tuning of the long- and short-range ordering in nanoparticle lattices, accompanied with corresponding changes of the effective optical properties.