Directed Self-Assembly of Colloidal Dumbbells with an Electric Field

We demonstrate the assembly of colloidal pal tidies with the shape of diatomic molecules ("dumbbells") into crystals that we study with confocal microscopy The literature on the preparation of nonspherical colloidal pal tides has grown steadily Assembly of these particles into regular three-dimensional crystalline lattices, however, is rarely, if ever, achieved and has not yet been studied quantitatively in 3D real space. We find that, by application of an electric field, such particles assemble quite readily By varying the pal tick aspect ratio, range of interactions, and electric field strength, we find several different crystal structures of which three have never before been observed Moreover, the electric field can be used to switch between different structures and manipulate/switch the photonic properties Moreover, our work sheds light on fundamental questions related to the sell-assembly of nonspherical particles