Electronic properties of metal-arene functionalized graphene

The coordination chemistry of oxide and nanocarbon materials

Understanding how a ligand affects the steric and electronic properties of a metal is the cornerstone of the inorganic chemistry enterprise. What happens when the ligand is an extended surface? This question is central to the design and implementation of state-of-the-art functional materials containing transition metals. This perspective will describe how these two very different sets of extended surfaces can form well-defined coordination complexes with metals. In the Green formalism, functionalities on oxide surfaces react with inorganics to form species that contain X-type or LX-type interactions between the metal and the oxide. Carbon surfaces are neutral L-type ligands; this perspective focuses on carbons that donate six electrons to a metal. The nature of this interaction depends on the curvature, and thereby orbital overlap, between the metal and the extended π-system from the nanocarbon.

Retained Carrier-Mobility and Enhanced Plasmonic-Photovoltaics of Graphene via ring-centered η6 Functionalization and Nanointerfacing

Binding graphene with auxiliary nanoparticles for plasmonics, photovoltaics, and/or optoelectronics, while retaining the trigonal-planar bonding of sp² hybridized carbons to maintain its carrier-mobility, has remained a challenge. The conventional nanoparticle-incorporation route for graphene is to create nucleation/attachment sites via "carbon-centered" covalent functionalization, which changes the local hybridization of carbon atoms from trigonal-planar sp² to tetrahedral sp³. This disrupts the lattice planarity of graphene, thus dramatically deteriorating its mobility and innate superior properties. Here, we show large-area, vapor-phase, "ring-centered" hexahapto (η⁶) functionalization of graphene to create nucleation-sites for silver nanoparticles (AgNPs) without disrupting its sp² character. This is achieved by the grafting of chromium tricarbonyl [Cr(CO)₃] with all six carbon atoms (sigma-bonding) in the benzenoid ring on graphene to form an (η⁶-graphene)Cr(CO)₃ complex. This nondestructive functionalization preserves the lattice continuum with a retention in charge carrier mobility (9% increase at 10 K); with AgNPs attached on graphene/n-Si solar cells, we report an ∼11-fold plasmonic-enhancement in the power conversion efficiency (1.24%).

Theoretical exploration on the electronic and magnetic properties of (FeCp)n– (n = 1, 2) ligand-functionalized graphene

The spin density plots of (FeCp)₂@G_i(i= 1–5).

Structure and electronic properties of bilayer graphene functionalized with half-sandwiched transition metal-cyclopentadienyl complexes

Tuning the electronic and magnetic properties of graphene is a crucial problem in the design of practical on-off electronic devices. Using density functional theory calculations, we explore the electronic and magnetic properties of bilayer graphene functionalized by cyclopentadienyl (Cp = cyclopentadienyl, C5H5) based half-sandwich ligands, CpTM (TM = Sc-Ni). It is found that the adsorption of CpTM ligands can introduce high magnetic moments and open the band gap of bilayer graphene, due to the electron doping as well as the asymmetric charge distribution between two graphene layers. Furthermore, the p-n doping of bilayer graphene by co-binding F/NO2 and CpTM on two external sides of BLG can further widen the band gap up to 366.1 meV. This study proposes an effective way to the modulation of the electronic and magnetic properties of graphene.

Electronic and magnetic properties regulation of finite to infinite half sandwich organo-transition-metal-complexes functionalized graphene

Total band gaps (Δt) and band gaps of free “graphene”, ignoring impurity bands of TM_nOLs (Δg).

Graphene-related nanomaterials: tuning properties by functionalization

In this review, we discuss the most recent progress on graphene-related nanomaterials, including doped graphene and derived graphene nanoribbons, graphene oxide, graphane, fluorographene, graphyne, graphdiyne, and porous graphene, from both experimental and theoretical perspectives, and emphasize tuning their stability, electronic and magnetic properties by chemical functionalization.