ABSTRACTThree-dimensional superlattices consisting of gold nanoparticles were grown at air/suspension or suspension/solid interfaces. The growth of superlattices was found to be strongly dependent on substrate materials: Micrometer-sized superlattices were grown at air/suspension interfaces and upon silver substrates, whereas no growth was observed on silicon, silicon oxide, or amorphous carbon substrates. To explain the observed substrate dependence, Lifshitz theory was used to calculate the Hamaker constants between gold nanoparticle assemblies and substrates through the suspension. Van der Waals interactions estimated from this calculation fully explain the experimental results.
Three-dimensional DNA-programmable nanoparticle superlattices