Production of Nitrogen-Doped Graphene by Low-Energy Nitrogen Implantation

Zhao, Wei; Höfert, Oliver; Gotterbarm, Karin; Zhu, Junfa; Papp, Christian; Steinrück, Hans‐Peter

doi:10.1021/jp209927m

Cited by 101 publications

(110 citation statements)

References 29 publications

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“…In fact, the magnetic field induced electron 11 confinement in the ECR configuration generates high temperature electron distribution tails of nearly 30 eV which lead to a relatively high degree of N2 dissociation without a significant increase in the potential or ion bombardment energies. 53 Considering that for both set of samples, the treatment time was kept the same; the ECR process produced significantly higher pyridinic nitrogen as compared to the rf-PECVD process and as such corroborates the results presented by Zhao et al 51 Using molecular dynamics, Åhlgren et al have…”

Section: 39supporting

confidence: 82%

Tuning the Electronic and Magnetic Properties of Nitrogen-Functionalized Few-Layered Graphene Nanoflakes

et al. 2017

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In this work, we report on the modification of electronic and magnetic properties of few layered graphene (FLG) nanoflakes via nitrogen functionalisation carried out using radio frequency (rf-PECVD) and electron cyclotron resonance (ECR) plasma processes. Even though the rf-PECVD N2 treatment leads to higher Ndoping levels in the FLGs (4.06 at%) as compared to the ECR process (2.18 at.%), the ferromagnetic behaviour of ECR FLG(118.62 x 10 -4 emu/gm) was significantly higher than the rf-PECVD (0.39 x 10 -4 emu/gm) and pristine graphene (3.47 x 10 -4 emu/gm). While both plasma processes introduce electron donating N-atoms in the graphene structure, distinct dominant nitrogen bonding configurations (pyridinic, pyrrolic) were observed for each FLG type. While, the ECR plasma introduces more sp 2 type nitrogen moieties, the rf-PECVD process led to the formation of sp 3 coordinated nitrogen functionalities, as confirmed through Raman measurements. The samples further characterised using X -ray absorption near edge spectroscopy (XANES) and X-ray, ultraviolet photoelectron spectroscopies revealed an increased electronic density of states and a significantly higher concentration of pyrrolic groups in the rf-PECVD samples. Due to the formation of reactive edge structures and pyridinic nitrogen moieties, the ECR functionalised FLGs expressed highest saturation magnetisation behaviour with the lowest field hysteretic features. In comparison, the rf-PECVD samples, displayed the lowest saturation magnetisation owing to the disappearance of magnetic edge states and formation of stable non-radical type defects in the pyrrole type structures. Our experimental results thus provide new evidence to control the magnetic and electronic properties of few layered graphene nanoflakes via control of the plasma-processing route.• INTRODUCTIONIntrinsic magnetism observed in materials without d-or f-electrons has attracted much interest, especially for carbon-based materials and in particular, graphene. There has been a long-standing interest in the development of ferromagnetic graphene for realizing its applications into spintronic devices via the combination of spin and charge. [1][2][3][4] The introduction of magnetic response in graphene via the introduction of edges, vacancy defects or adsorbed atoms has been investigated using both theoretical and experimental means. [1][2][3][4][5][6][7][8][9][10][11][12][13] Various theoretical studies. [3][4][5][6][7][8][9][10] have suggested that zigzag edges or point defects in graphene as the spin units should 3 carry magnetic moment with possible long-range order coupling. This coupling itself can be ferromagnetic or antiferromagnetic, depending on whether the zigzag edges or defects correspond to the same or to different hexagonal sub-lattice of the graphene lattice, respectively. At present, the intrinsic magnetic properties of finite sized graphene sheet are far from being understood, given that the magnetic signal from a finite sized graphene sheet is too weak to be detected by macr...

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Section: 39supporting

confidence: 82%

Tuning the Electronic and Magnetic Properties of Nitrogen-Functionalized Few-Layered Graphene Nanoflakes

et al. 2017

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“…Doping by keV ion implantation has been studied theoretically [14] and it was shown that the substrate enhances the chances for successfull indirect implantation. Experimentally, ion implantation in epitaxial graphene grown on SiC as well as on Ni(111) has been performed by irradiation with slow (keV) nitrogen ions at high fluences [15,16]. In freestanding graphene single atom substitution has been demonstrated [17].…”

Section: Cimap (Cea-cnrs-ensicaen-ucbn) 14070 Caen Cedex 5 Francementioning

confidence: 99%

“…The atoms would stem from the underlying substrate. It has already been proposed in a theoretical paper by Zhao et al that indirect implantation of graphene might be possible with keV ions [16]. In the case of SHI the ejection of surface material is caused by a different process, e.g.…”

Section: (B)mentioning

confidence: 99%

Manipulation of the graphene surface potential by ion irradiation

et al. 2013

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We show that the work function of exfoliated single layer graphene can be modified by irradiation with swift (E kin = 92 MeV) heavy ions under glancing angles of incidence. Upon ion impact individual surface tracks are created in graphene on SiC. Due to the very localized energy deposition characteristic for ions in this energy range, the surface area which is structurally altered is limited to ≈ 0.01 µm 2 per track. Kelvin probe force microscopy reveals that those surface tracks consist of electronically modified material and that a few tracks suffice to shift the surface potential of the whole single layer flake by ≈ 400 meV. Thus, the irradiation turns the initially n-doped graphene into p-doped graphene with a hole density of 8.5 × 10 12 holes/cm 2 . This doping effect persists even after heating the irradiated samples to 500 • C. Therefore, this charge transfer is not due to adsorbates but must instead be attributed to implanted atoms. The method presented here opens up a new way to efficiently manipulate the charge carrier concentration of graphene.

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“…Note that, as a surface modifi cation approach, which species indeed plays the most important role in improving the electrochemical performance of an electrode material, it is still unclear now, although some work about the nitrogen-doped carbon coated electrode materials has already been reported for LIBs. [ 32 ] Here, N-doped carbon coating are initially adopted in Na 3 V 2 (PO 4 ) 3 cathode material for SIBs, and found, compared with the bare carbon coated Na 3 V 2 (PO 4 ) 3 , N-doped carbon coated Na 3 V 2 (PO 4 ) 3 composite exhibits a remarkable improvement in Na storage property, especially its rate performance. Furthermore, the modifi cation effects of various nitrogen types on electrochemical performance are explored in detail, and gives a direct evidence of what kind of N-doped species has the largest impact on an electrode material for SIBs.…”

Section: Introductionmentioning

confidence: 99%

Nitrogen‐Doping‐Induced Defects of a Carbon Coating Layer Facilitate Na‐Storage in Electrode Materials

Shen

Wang

et al. 2014

Advanced Energy Materials

345

190

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systems of lower decomposition potential or water-based electrolytes, which also make SIBs cheaper than LIBs. [ 2 ] Over the past decade, a series of important results has triggered increasing academic interest in room temperature SIBs. Actually, in recent years, many electrode materials of room temperature SIBs, such as layered NaMO 2 (M = Co, Mn, Ni, Cr, V, etc.), [5][6][7][8][9][10][11][12] phosphates [ 13 ] and fl uorophosphates [ 14 ] as cathodes, and low potential metal oxides, [15][16][17] and carbon materials [ 20,21 ] as anodes materials have been extensively studied.However, because of the larger ionic radius of Na + (1.02 Å) than Li + (0.76 Å) and the higher equivalent weight of Na than Li, when Na + is inserted into/extracted from the host materials, the impact on the structure of host materials becomes more serious. Therefore, the cycle life and structural stability of the above-mentioned materials are still far from a satisfactory target. It seems very necessary and desirable for developing new kinds of electrode materials with good electrochemical performance to satisfy the application of SIBs in the future. Nowadays, advanced electrode materials with high capacity and stable long-term cycle life are critical for SIBs. Recently, active phosphates with NASICON structure, particularly sodium vanadium phosphate (Na 3 V 2 (PO 4 ) 3 ), have received considerable attention because this material possesses a rhombohedral R-3c symmetry that can generate large interstitial spaces through which sodium ions can diffuse. [ 2,22 ] NASICON-type Na 3 V 2 (PO 4 ) 3 displays two potential plateaus located at 1.6 V and 3.4 V vs. Na/Na + , corresponding to the V 2+ /V 3+ and V 3+ /V 4+ redox couple, respectively. [ 23 ] Moreover, its theoretical discharge capacity varies between 118 and 236 mAh g −1 based on the potential window and the variation between V 3+ /V 4+ and V 2+ / V 3+ redox states. [ 23,24 ] However, it should be pointed out that the low electrical conductivity of Na 3 V 2 (PO 4 ) 3 , which is similar to LiFePO 4 and Li 3 V 2 (PO 4 ) 3 , seriously limits its electrochemical performance, in particular the rate stability at high current density. [ 25 ] Therefore, numerous strategies should be attempted to improve the rate performance, such as decreasing the particle size, carbon or other conductive material coating and metal ion doping. [ 26,27 ] In particular, carbon coating is regarded as a lowcost and high-effi ciency way towards improving the conductivity of electrode materials and has been already widely applied to certain electrode materials of LIBs, [26][27][28] such as Li 3 V 2 (PO 4 ) 3 , LiMnPO 4 and LiFePO 4 . However, due to the above-mentioned A nitrogen-doped, carbon-coated Na 3 V 2 (PO 4 ) 3 cathode material is synthesized and the formation of doping type of nitrogen-doped in carbon coating layer is systemically investigated. Three different carbon-nitrogen species: pyridinic N, pyrrolic N, and quaternary N are identifi ed. The most important fi nding is that different carbon-nitrogen specie...

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Production of Nitrogen-Doped Graphene by Low-Energy Nitrogen Implantation

Cited by 101 publications

References 29 publications

Tuning the Electronic and Magnetic Properties of Nitrogen-Functionalized Few-Layered Graphene Nanoflakes

Tuning the Electronic and Magnetic Properties of Nitrogen-Functionalized Few-Layered Graphene Nanoflakes

Manipulation of the graphene surface potential by ion irradiation

Nitrogen‐Doping‐Induced Defects of a Carbon Coating Layer Facilitate Na‐Storage in Electrode Materials

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