Tailoring Anisotropic Morphology at the Nanoregime: Surface Bonding Motif Determines the Morphology Transformation of ZnO Nanostructures

A quantitative relationship between bond length, crystal morphology, and particle size has been established to investigate the morphology transformation of ZnO nanostructures at the nanoregime. Surface bonding conditions dominate the anisotropic growth of ZnO nanoparticles. Critical surface bond lengths at which ZnO can respectively exhibit pyramid-, truncated pencil-, pencil-, and rod-like morphologies were quantitatively calculated under different extension/shrinkage degrees of Zn–O bond length in the lattice. The size of particular ZnO nanostructures was obtained by tracking the variation of bond length in the lattice. At the nanoregime, ZnO thermodynamically prefers to exhibit nanorods with a diameter smaller than 3.60 nm, nanopyramids with size smaller than 2.94 nm, nanopencils with a diameter larger than 3.15 nm, and truncated nanopencils with a diameter larger than 3.92 nm. Our results are in agreement with experimental observations and indicate the fundamental role of surface bonding control in tailoring anisotropic growth of ZnO nanostructures.