Dispersive and covalent interactions in all-carbon heterostructures consisting of penta-graphene and fullerene: topological effect

摘要

All-carbon heterostructures consisting of carbon allotropes have attracted considerable attention because of their intriguing properties. However, understanding is still lacking of the interactions at the interface, as well as the connection between such interactions and their performance. Herein, we systematically explore the interfacial interaction in all-carbon penta-graphene (PG)/C-20 (C-60) heterostructures, and its effect on structural and electronic properties. Based on first-principles calculations, we report that the all-carbon PG/C-20 (C-60) heterostructures show two types of interfacial interactions: dispersive and covalent. The PG/ C-20 van der Waals (vdWs) heterostructure is less stable than its covalent one. By contrast, the PG/C-60 vdWs heterostructure is the more stable. In the covalent heterostructures, either two or four C-C bonds can be formed between PG and C-20, whereas only two can be formed between PG and C-60. The near-gap electronic structures depend on the interfacial interactions, and the levels near the Fermi level are mainly composed of C-20 (C-60) states, giving rise to a small band gap of heterostructure, making them promising for visible light absorption. All the differences in these PG/C-20 (C-60) heterostructures can be well understood in terms of the different topology of fullerene. This finding indicates that all-carbon PG/fullerene heterostructures are promising candidates for photocatalysis. photodetectors, and solar energy harvesting and conversion.