Multiple twinning drives nanoscale hyper-branching of titanium dioxide nanocrystals

A novel twinning-driven hyper-branching mechanism of 1-dimensional nanowires is demonstrated to provide a clear understanding of the growth behaviour of a complex nanocrystal structure. Specifically, we have discovered that the multiple twinning mechanism can be successfully applied to the hyper-branching of nanowires. Systematic variations of TiO₂ hyper-branching in terms of branching multiplicity, branching angle, and size were observed, depending on the sequence, the degree, and the combination of two different twinning modes of contact and interpenetration. The twinning process is a reliable synthetic protocol for next generation nanostructures which require highly complex, but predictable shape and symmetry.