Anisotropy Engineering of ZnO Nanoporous Frameworks: A Lattice Dynamics Simulation

The anisotropy engineering of nanoporous zinc oxide (ZnO) frameworks has been performed by lattice dynamics simulation. A series of zinc oxide (ZnO) nanoporous framework structures was designed by creating nanopores with different sizes and shapes. We examined the size effects of varying several features of the nanoporous framework (namely, the removal of layers of atoms, surface-area-to-volume ratio, coordination number, porosity, and density) on its mechanical properties (including bulk modulus, Young's modulus, elastic constant, and Poisson ratio) with both lattice dynamics simulations. We also found that the anisotropy of nanoporous framework can be drastically tuned by changing the shape of nanopores. The maximum anisotropy (defined by Y-max/Y-min) of the Young's modulus value increases from 1.2 for bulk ZnO to 2.5 for hexagon-prism-shaped ZnO nanoporous framework structures, with a density of 2.72 g/cm(3), and, even more remarkably, to 89.8 for a diamond-prism-shape at a density of 1.72 g/cm(3). Our findings suggest a new route for desirable anisotropy and mechanical property engineering with nanoporous frameworks by editing the shapes of the nanopores for the desired anisotropy.

Automated summary

The anisotropy engineering of nanoporous zinc oxide (ZnO) frameworks has been studied using lattice dynamics simulation. Different sizes and shapes of nanopores were created to design a series of ZnO nanoporous framework structures. The effects of various features of the nanoporous framework on its mechanical properties were examined, and it was found that the anisotropy of the framework can be significantly tuned by changing the shape of the nanopores. The findings suggest a new route for desirable anisotropy and mechanical property engineering with nanoporous frameworks.