Structures and Properties of Planar Ge₃O₃ Cluster and Its Buckled Honeycomb Two-Dimensional Nanostructure

The discovery of graphene and its excellent properties inspired the search for more two-dimensional (2D) materials. Understanding the structures and properties of the smallest repeating units as well as crystal 2D materials is helpful for designing 2D materials. As germanium tends to form three-dimensional structures, the preparation of germanium-based 2D nanomaterials is still a challenge. Herein, we report a Ge₃O₃ cluster with the potential to construct a germanium oxide 2D nanostructure. We conduct a combined anion photoelectron spectroscopy and theoretical study on Ge₃O₃^-/0. The structure of Ge₃O₃^- is a C_s symmetric nonplanar six-membered ring, while that of Ge₃O₃ is a D_3h symmetric planar six-membered ring. Chemical bonding analyses reveal that Ge₃O₃ exhibits π aromaticity. First-principle results suggest that a buckled honeycomb 2D nanostructure with a wide band gap of 3.14 eV may be produced based on Ge₃O₃, which is promising in optoelectronic applications especially in blue, violet, and ultraviolet regions.