Shape, orientation, and stability of twinned gold nanorods

Although energetically unfavorable, twinning is often observed in many faceted nanomaterials including nanocrystals, nanorods, and nanowires, even following annealing. Unfortunately, twinning is neglected by most analytical models, which consequentially limits theoretical descriptions of nanostructured materials to more idealized (less realistic) approximations. In the present study, a new general analytical model for the investigation of nanomaterials of arbitrary shape and with any configuration of twin planes is used to examine twinning in unsupported gold nanorods of various orientations and aspect ratios. The results point to a close competition between nonconvex pentagonal nanorods, and 〈011〉 oriented face-centered cubic (fcc) nanorods containing multiple longitudinal twin planes, in excellent agreement with experimental studies reported in the literature.