Effects of hydrostatic pressure on structural, mechanical, and electronic properties of energetic molecular perovskite (C6H14N2)(NH2NH3)(ClO4)3: a DFT-D insight

Abstract

Dispersion corrected density functional theory (DFT-D) calculations were conducted to examine the high-pressure behaviour of energetic molecular perovskite (C₆H₁₄N₂)(NH₂NH₃)(ClO₄)₃, called DAP-7, a promising new type of heat-resistant energetic material. The structural, mechanical, and electronic properties and intermolecular interactions of DAP-7 in the hydrostatic pressure range of 0–40 GPa were reported. The evolution of lattice constants with pressure demonstrated that the DAP-7 crystal exhibited an anisotropic compression behaviour due to the fact that the DAP-7 crystal is more easily compressed along the a- and c-axes than the b-axis. A study of elastic constants and mechanical properties revealed that this compound shows an increase in ductility, deformation resistance and stiffness but a decrease in elastic anisotropy under pressure. The band gap value decreased gradually with pressure, which indicates an increase in impact sensitivity under the applied pressure. In addition, a comprehensive analysis of the Hirshfeld surface and two-dimensional fingerprint plots revealed that the H⋯O (O⋯H) hydrogen bond, which dominates intermolecular interactions, accounted for a decreasing proportion of the Hirshfeld surface, but it enhanced in strength with increasing pressure.