Impacts of structural downscaling of inorganic molecular crystals - A DFT study of Sb2O3

Abstract

Inorganic molecular Crystals (IMCs) is an emerging class of two-dimensional (2D) materials having unconnected structural units. In contrast to the conventional 2D materials, Sb2O3 appears in the form of periodically arranged van-der-Waals (vdWs) molecular clusters. Besides the specific material's features, IMCs offer unique features due to anisotropy in bonding, packing, electronic and thermal conductivity, and optical characteristics. The work reported herein depicts the modification in structural and electronic properties of Sb2O3 trimmed from bulk to lower dimensions. The shortening in bond-lengths pointing to variation in inter-cage interactions and decrease in band gap are observed with the structural downscaling. The bulk, slab (111), slab (001) and clusters are semiconductors with the major contribution arising from Sb and O in formation of conduction and valence bands respectively. The electronic properties of the materials pointed to p-p hybridization and hence presence of π-bonding and anti-bonding molecular orbitals within the region present between the molecular cages.

Keywords: Molecular Crystals, 2D materials, Thermal conductivity, Valence bands, Molecular orbitals