First-principles studies of the caged germanium clusters with gold doping and their adsorption on graphdiyne nanosheets

Abstract

Graphdiyne (GDY) is a novel two-dimensional (2D) carbon material, and has the promising applications due to its unique structural features. A new series of GDY-based complexes was theoretically designed by adsorbing the AuGen (n = 14–16) clusters on GDY surface, namely AuGen-GDY complexes, and the geometries, electronic properties, and optical absorption spectra of these complexes were systematically studied using density functional theory calculations. Firstly, the stable structures of endohedral AuGen (n = 14–16) clusters were successfully found. The endohedral clusters possess high chemical stability, strong aromaticity, and delocalized 4c-2e and 5c-2e σ-bonds. Besides, the AuGen clusters can stably adsorb on triangular hole of conjugated GDY surface, by not only covalent bonds, but also weak interactions (e.g., van der Waals). Moreover, the addition of GDY reduced the HOMO-LUMO gaps and natural charges on Au atom, while GDY can effectively modulate the electronic structures of complexes. The optical absorption spectra of AuGen-GDY were discussed, and the type of the main electronic transitions is local excitation, which can be further confirmed by the hole-electron distributions. This study not only highlights the important of the adsorption of endohedral clusters on GDY surface, but also stimulates the further synthesis as potential candidate of novel GDY-based cluster-assembled materials.