Continuous Shape Tuning of Nanotetrapods: Toward Shape-Mediated Self-Assembly

We describe a surfactant-driven method to synthesize highly monodisperse CdSe-seeded CdS tetrapods with differing arm lengths and diameters in order to examine their effects on self-assembly. We exploited the phenomena of weak- and strong-binding capping groups to tune the arm length and diameter with uniform shape and achieved >95% yield. Afterward, we utilize these particles to overcome some of the key problems in the assembly of anisotropic shaped particles. Intriguingly, we found that tetrapods with certain arm lengths pack like fishbone chains, which was greatly dependent on particle shape and size. These ordered assembly phenomena were understood with the assistance of computer simulations, which strongly support our experimental observations. Importantly, this work presents a synthetic route toward shape tuning in CdSe-seeded CdS tetrapod structures, which has great influence on their self-assembly behavior at the solution/substrate interface.