Nitrogen-Doping Enables Covalent-Like pi-pi Bonding between Graphenes

Journal Article · Thu Jan 01 00:00:00 EST 2015 · Nano Letters

OSTI ID:1193191

Tian, Yong-Hui ^[1]; Huang, Jingsong ^[2]; Sumpter, Bobby G ^[2]; Kertesz, Prof. Miklos ^[1]

---

1. Georgetown University
2. ORNL

The neighboring layers in bi-layer (and few-layer) graphenes of both AA and AB stacking motifs are known to be separated at a distance corresponding to van der Waals (vdW) interactions. In this Letter, we present for the first time a new aspect of graphene chemistry in terms of a special chemical bonding between the giant graphene molecules . Through rigorous theoretical calculations, we demonstrate that the N-doped graphenes (NGPs) with various doping levels can form an unusual two-dimensional (2D) pi pi bonding in bi-layer NGPs bringing the neighboring NGPs to significantly reduced interlayer separations. The interlayer binding energies can be enhanced by up to 50% compared to the pristine graphene bi-layers that are characterized by only vdW interactions. Such an unusual chemical bonding arises from the pi pi overlap across the vdW gap while the individual layers maintain their in-plane pi-conjugation and are accordingly planar. The existence of the resulting interlayer covalent-like bonding is corroborated by electronic structure calculations and crystal orbital overlap population (COOP) analyses. In NGP-based graphite with the optimal doping level, the NGP layers are uniformly stacked and the 3D bulk exhibits metallic characteristics both in the in-plane and along the stacking directions.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1193191
• Journal Information: Nano Letters, Vol. TBD
• Country of Publication: United States
• Language: English