Electronic Structure Of Nitrogen Research Articles

Electronic Structure of Nitrogen- and Phosphorus-Doped Graphenes Grown by Chemical Vapor Deposition Method.

Heteroatom doping is a widely used method for the modification of the electronic and chemical properties of graphene. A low-pressure chemical vapor deposition technique (CVD) is used here to grow pure, nitrogen-doped and phosphorous-doped few-layer graphene films from methane, acetonitrile and methane-phosphine mixture, respectively. The electronic structure of the films transferred onto SiO2/Si wafers by wet etching of copper substrates is studied by X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy using a synchrotron radiation source. Annealing in an ultra-high vacuum at ca. 773 K allows for the removal of impurities formed on the surface of films during the synthesis and transfer procedure and changes the chemical state of nitrogen in nitrogen-doped graphene. Core level XPS spectra detect a low n-type doping of graphene film when nitrogen or phosphorous atoms are incorporated in the lattice. The electrical sheet resistance increases in the order: graphene < P-graphene < N-graphene. This tendency is related to the density of defects evaluated from the ratio of intensities of Raman peaks, valence band XPS and NEXAFS spectroscopy data.

The atomic and electronic structure of nitrogen- and boron-doped phosphorene.

First principles modeling of nitrogen- and boron-doped phosphorene demonstrates the tendency toward the formation of highly ordered structures. Nitrogen doping leads to the formation of -N-P-P-P-N- lines. Further transformation into -P-N-P-N- lines across the chains of phosphorene occurs with increasing band gap and increasing nitrogen concentration, which coincides with the decreasing chemical activity of N-doped phosphorene. In contrast to the case of nitrogen, boron atoms prefer to form -B-B- pairs with the further formation of -P-P-B-B-P-P- patterns along the phosphorene chains. The low concentration of boron dopants converts the phosphorene from a semiconductor into a semimetal with the simultaneous enhancement of its chemical activity. Co-doping of phosphorene by both boron and nitrogen starts from the formation of -B-N- pairs, which provides flat bands and further transformation of these pairs into hexagonal BN lines and ribbons across the phosphorene chains.

Theoretical Prediction of Potentially New Highly Conducting Polymer Complexes: Veh Study of Nitrogen and Oxygen Containing Conjugated Polymers

Abstract The electronic structure of nitrogen and oxygen containing conjugated polymers is investigated by means of the Valence Effective Hamiltonian (VEH) technique. Parameters related to the conductivity properties upon doping such as ionization potentials, bandgaps, and bandwidths are discussed in detail for polyaniline, polyquinoline, polyfuran, poly(p-phenylene oxide), and polybenzofuran.

The complexing ability and structure of Si-substituted silatranes

The proton NMR spectra of Si-substituted silatranes, a new class of biologically active compounds, measured in the presence of Co 2+, Ni 2+ and Eu 3+ ions are examined. These silatranes coordinate with Co 2+ and Ni 2+ through a nitrogen atom and with Eu 3+ through an oxygen atom mainly without transition to the exo-form. The electronic structure of nitrogen in silatranes is the same as that of pyrrol nitrogen. This suggests that in silatranes a nitrogen lone pair and oxygen lone pairs form common electron system analogous, for example, to the π-system of unsaturated cycles.