Probing the Bonding in Nitrogen-Doped Graphene Using Electron Energy Loss Spectroscopy

Nicholls, Rebecca J.; Murdock, Adrian T.; Tsang, Joshua; Britton, Jude; Pennycook, Timothy J.; Koós, Antal A.; Nellist, Peter D.; Grobert, Nicole; Yates, Jonathan R.

doi:10.1021/nn402489v

Cited by 74 publications

(84 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The nitrogen 1s (N1s) ELNES, expanded in Figure 3E, show a strong peak at ~401 eV, with very little signal at energies above this. Comparing the spectra to density functional theory (DFT) ELNES calculations of possible single nitrogen defects, there is excellent agreement with the spectrum for substitutional nitrogen ( 2B) and with recent works on nitrogen doped graphene (19)(20)(21). The spectrum shows a number of signature features, which would be lost in a signal averaged with other nitrogen configurations.…”

supporting

confidence: 74%

Atomic Configuration of Nitrogen-Doped Single-Walled Carbon Nanotubes

et al. 2014

View full text Add to dashboard Cite

Abstract:Having access to the chemical environment at the atomic level of a dopant in a nanostructure is crucial for the understanding of its properties. We have performed atomicallyresolved electron energy-loss spectroscopy to detect individual nitrogen dopants in single-walled carbon nanotubes and compared with first principles calculations. We demonstrate that nitrogen doping occurs as single atoms in different bonding configurations: graphitic-like and pyrroliclike substitutional nitrogen neighbouring local lattice distortion such as Stone-Thrower-Wales defects. The stability under the electron beam of these nanotubes has been studied in two extreme cases of nitrogen incorporation content and configuration. These findings provide key information for the applications of these nanostructures. Doped carbon nanotubes (NT), notably nitrogen-doped (CN x -NT), have attracted much attention because of their interesting physical and chemical properties (1)(2)(3)(4). Knowledge of the atomic arrangement of the dopant atoms in such nanostructures is essential for a complete understanding of the material's electronic properties, e.g. field emission (5) or transport (6) properties. This requires precision measurements, combining high spatial resolution and high spectroscopic sensitivity. Several techniques have been deployed with this aim, but until now none of them have provided the required information in such nanostructures. Most characterization techniques, such as Raman spectroscopy and x-ray absorption spectroscopy (XAS), have relatively low spatial resolution, of the order of hundreds of nanometers, and in some cases only provide indirect information (1,2). Thus, local structural and analytical methods are needed. Scanning tunneling microscopy (STM) and spectroscopy (STS) are local techniques for studying the structural and electronic features/properties of materials. Indeed, some studies have been reported on CN x -NT (7-9) and recently also on N-doped graphene (10,11). However, chemical characterization cannot be unambiguously performed from the STM/STS analysis. Indeed, the interpretation of the results remains complicated, as different local structures may give rise to similar features (7-11). In this sense, high-resolution transmission electron microscopy (HRTEM) and scanning TEM (STEM) combined with electron energy-loss spectroscopy (EELS) have provided very valuable and rich information at the atomic scale (12).Great progress has been made in (S)TEM due to the development of aberration-corrected microscopes (12)(13)(14). Recent work has demonstrated that annular dark-field imaging performed in a C s -probe corrected STEM enables quantitative atom-by-atom analysis of 2D low-Z materials such as h-BN (13). Single atoms have also been investigated via STEM-EELS in these materials (12,(14)(15)(16)(17)(18)(19)(20)(21). Three recent works have demonstrated the possibility to identify by STEM-EELS the presence of N atoms in graphene (19)(20)(21). In addition, N atoms have been also detected in Nimplanted multi-walle...

show abstract

supporting

confidence: 74%

Atomic Configuration of Nitrogen-Doped Single-Walled Carbon Nanotubes

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Early x-ray diffraction 1,17 and angle resolved ultraviolet photoelectron experiments 18 reported the first measurements of the lattice parameters, band structure, and stable stacking arrangement for bulk black phosphorus. Complementary experimental EELS and theoretical modeling has been effectively employed to analyze the electronic structure of other layered materials such as graphene oxide, 24 graphene, 25 and boron nitride 26 but has yet to be performed for black phosphorus. Techniques such as scanning tunneling microscopy, 19 atomic force microscopy (AFM), 6,20 conventional transmission electron microscopy (CTEM), 21,22 and Raman spectroscopy 22,23 have all contributed to the experimental characterization of atomically thin black phosphorus.…”

Section: Introductionmentioning

confidence: 99%

Atomic and electronic structure of exfoliated black phosphorus

Topsakal

Low

et al. 2015

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

View full text Add to dashboard Cite

Electronic structure, chemical bonding features, and electron charge density of the double-cubane single crystal [ Sb 7 S 8 Br 2 ] ( AlCl 4 ) 3 Appl. Phys. Lett. 98, 201903 (2011); 10.1063/1.3583674Structural characterization and electron-energy-loss spectroscopic study of pulsed laser deposited Li Nb O 3 films on a -sapphire Black phosphorus, a layered two-dimensional crystal with tunable electronic properties and high hole mobility, is quickly emerging as a promising candidate for future electronic and photonic devices. Although theoretical studies using ab initio calculations have tried to predict its atomic and electronic structure, uncertainty in its fundamental properties due to a lack of clear experimental evidence continues to stymie our full understanding and application of this novel material. In this work, aberration-corrected scanning transmission electron microscopy and ab initio calculations are used to study the crystal structure of few-layer black phosphorus. Directly interpretable annular dark-field images provide a three-dimensional atomic-resolution view of this layered material in which its stacking order and all three lattice parameters can be unambiguously identified. In addition, electron energy-loss spectroscopy (EELS) is used to measure the conduction band density of states of black phosphorus, which agrees well with the results of density functional theory calculations performed for the experimentally determined crystal. Furthermore, experimental EELS measurements of interband transitions and surface plasmon excitations are also consistent with simulated results. Finally, the effects of oxidation on both the atomic and electronic structure of black phosphorus are analyzed to explain observed device degradation. The transformation of black phosphorus into amorphous PO 3 or H 3 PO 3 during oxidation may ultimately be responsible for the degradation of devices exposed to atmosphere over time.

show abstract

“…[1][2][3][4][5][6][7][8] Hence effective doping and the controlled adjustment of the Fermi level are of crucial importance. [13][14][15] Numerous graphene doping schemes have been reported [16][17][18][19][20][21][22] including charge transfer from metal oxide, 7-9 molecular films and chemical doping via e.g. [13][14][15] Numerous graphene doping schemes have been reported [16][17][18][19][20][21][22] including charge transfer from metal oxide, 7-9 molecular films and chemical doping via e.g.…”

Section: Introductionmentioning

confidence: 99%

Engineering high charge transfer n-doping of graphene electrodes and its application to organic electronics

et al. 2015

View full text Add to dashboard Cite

Using thermally evaporated cesium carbonate (Cs2CO3) in an organic matrix, we present a novel strategy for efficient n-doping of monolayer graphene and a ∼90% reduction in its sheet resistance to ∼250 Ohm sq(-1). Photoemission spectroscopy confirms the presence of a large interface dipole of ∼0.9 eV between graphene and the Cs2CO3/organic matrix. This leads to a strong charge transfer based doping of graphene with a Fermi level shift of ∼1.0 eV. Using this approach we demonstrate efficient, standard industrial manufacturing process compatible graphene-based inverted organic light emitting diodes on glass and flexible substrates with efficiencies comparable to those of state-of-the-art ITO based devices.

show abstract

Probing the Bonding in Nitrogen-Doped Graphene Using Electron Energy Loss Spectroscopy

Cited by 74 publications

References 25 publications

Atomic Configuration of Nitrogen-Doped Single-Walled Carbon Nanotubes

Atomic Configuration of Nitrogen-Doped Single-Walled Carbon Nanotubes

Atomic and electronic structure of exfoliated black phosphorus

Engineering high charge transfer n-doping of graphene electrodes and its application to organic electronics

Contact Info

Product

Resources

About