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Cutroneo M, Torrisi L, Silipigni L, Michalcova A, Havranek V, Mackova A, Malinsky P, Lavrentiev V, Noga P, Dobrovodsky J, Slepicka P, Fajstavr D, Andò L, Holy V. Compositional and Structural Modifications by Ion Beam in Graphene Oxide for Radiation Detection Studies. Int J Mol Sci 2022; 23:ijms232012563. [PMID: 36293417 PMCID: PMC9604086 DOI: 10.3390/ijms232012563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 09/30/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022] Open
Abstract
In the present study, graphene oxide foils 10 μm thick have been irradiated in vacuum using same charge state (one charge state) ions, such as protons, helium and oxygen ions, at the same energies (3 MeV) and fluences (from 5 × 1011 ion/cm2 to 5 × 1014 ion/cm2). The structural changes generated by the ion energy deposition and investigated by X-ray diffraction have suggested the generation of new phases, as reduced GO, GO quantum dots and graphitic nanofibers, carbon nanotubes, amorphous carbon and stacked-cup carbon nanofibers. Further analyses, based on Rutherford Backscattering Spectrometry and Elastic Recoil Detection Analysis, have indicated a reduction of GO connected to the atomic number of implanted ions. The morphological changes in the ion irradiated GO foils have been monitored by Transmission Electron, Atomic Force and Scanning Electron microscopies. The present study aims to better structurally, compositionally and morphologically characterize the GO foils irradiated by different ions at the same conditions and at very low ion fluencies to validate the use of GO for radiation detection and propose it as a promising dosimeter. It has been observed that GO quantum dots are produced on the GO foil when it is irradiated by proton, helium and oxygen ions and their number increases with the atomic number of beam gaseous ion.
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Affiliation(s)
- Mariapompea Cutroneo
- Nuclear Physics Institute AS CR, Hlavni 130, 250 68 Rez, Czech Republic
- Correspondence:
| | - Lorenzo Torrisi
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, 98166 Messina, Italy
- INFN Sections of Catania, S. Sofia 64, 95123 Catania, Italy
| | - Letteria Silipigni
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, 98166 Messina, Italy
- INFN Sections of Catania, S. Sofia 64, 95123 Catania, Italy
| | - Alena Michalcova
- Department of Metals and Corrosion Engineering, University of Chemistry and Technology, Technická 5, 166 28 Prague, Czech Republic
| | - Vladimir Havranek
- Nuclear Physics Institute AS CR, Hlavni 130, 250 68 Rez, Czech Republic
| | - Anna Mackova
- Nuclear Physics Institute AS CR, Hlavni 130, 250 68 Rez, Czech Republic
- Department of Physics, Faculty of Science, University of J. E. Purkyně, Pasterouva 3544/1, 400 96 Ústí nad Labem, Czech Republic
| | - Petr Malinsky
- Nuclear Physics Institute AS CR, Hlavni 130, 250 68 Rez, Czech Republic
- Department of Physics, Faculty of Science, University of J. E. Purkyně, Pasterouva 3544/1, 400 96 Ústí nad Labem, Czech Republic
| | - Vasily Lavrentiev
- Nuclear Physics Institute AS CR, Hlavni 130, 250 68 Rez, Czech Republic
| | - Pavol Noga
- Faculty of Materials Science and Technology in Trnava, Advanced Technologies Research Institute, Slovak University of Technology in Bratislava, Jána Bottu 25, 91724 Trnava, Slovakia
| | - Jozef Dobrovodsky
- Faculty of Materials Science and Technology in Trnava, Advanced Technologies Research Institute, Slovak University of Technology in Bratislava, Jána Bottu 25, 91724 Trnava, Slovakia
| | - Petr Slepicka
- Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague, Czech Republic
| | - Dominik Fajstavr
- Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague, Czech Republic
| | - Lucio Andò
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, 98166 Messina, Italy
| | - Vaclav Holy
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Praha, Czech Republic
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Bakardjieva S, Plocek J, Ismagulov B, Kupčík J, Vacík J, Ceccio G, Lavrentiev V, Němeček J, Michna Š, Klie R. The Key Role of Tin (Sn) in Microstructure and Mechanical Properties of Ti2SnC (M2AX) Thin Nanocrystalline Films and Powdered Polycrystalline Samples. Nanomaterials 2022; 12:nano12030307. [PMID: 35159651 PMCID: PMC8839355 DOI: 10.3390/nano12030307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/08/2022] [Accepted: 01/12/2022] [Indexed: 11/23/2022]
Abstract
Layered ternary Ti2SnC carbides have attracted significant attention because of their advantage as a M2AX phase to bridge the gap between properties of metals and ceramics. In this study, Ti2SnC materials were synthesized by two different methods—an unconventional low-energy ion facility (LEIF) based on Ar+ ion beam sputtering of the Ti, Sn, and C targets and sintering of a compressed mixture consisting of Ti, Sn, and C elemental powders up to 1250 °C. The Ti2SnC nanocrystalline thin films obtained by LEIF were irradiated by Ar+ ions with an energy of 30 keV to the fluence of 1.1015 cm−2 in order to examine their irradiation-induced resistivity. Quantitative structural analysis obtained by Cs-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) confirmed transition from ternary Ti2SnC to binary Ti0.98C carbide due to irradiation-induced β-Sn surface segregation. The nanoindentation of Ti2SnC thin nanocrystalline films and Ti2SnC polycrystalline powders shows that irradiation did not affect significantly their mechanical properties when concerning their hardness (H) and Young’s modulus (E). We highlighted the importance of the HAADF-STEM techniques to track atomic pathways clarifying the behavior of Sn atoms at the proximity of irradiation-induced nanoscale defects in Ti2SnC thin films.
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Affiliation(s)
- Snejana Bakardjieva
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, 250 68 Husinec-Rez, Czech Republic; (J.P.); (B.I.); (J.K.)
- Faculty of Mechanical Engineering, JE Purkyně University, Pasteurova 1, 400 96 Ústí nad Labem, Czech Republic;
- Correspondence:
| | - Jiří Plocek
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, 250 68 Husinec-Rez, Czech Republic; (J.P.); (B.I.); (J.K.)
| | - Bauyrzhan Ismagulov
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, 250 68 Husinec-Rez, Czech Republic; (J.P.); (B.I.); (J.K.)
- Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Prague, Czech Republic
| | - Jaroslav Kupčík
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, 250 68 Husinec-Rez, Czech Republic; (J.P.); (B.I.); (J.K.)
| | - Jiří Vacík
- Nuclear Physics Institute, Czech Academy of Sciences, 250 68 Husinec-Rez, Czech Republic; (J.V.); (G.C.); (V.L.)
| | - Giovanni Ceccio
- Nuclear Physics Institute, Czech Academy of Sciences, 250 68 Husinec-Rez, Czech Republic; (J.V.); (G.C.); (V.L.)
| | - Vasily Lavrentiev
- Nuclear Physics Institute, Czech Academy of Sciences, 250 68 Husinec-Rez, Czech Republic; (J.V.); (G.C.); (V.L.)
| | - Jiří Němeček
- Faculty of Civil Engineering, Czech Technical University in Prague, Thakurova 7, 166 29 Prague, Czech Republic;
| | - Štefan Michna
- Faculty of Mechanical Engineering, JE Purkyně University, Pasteurova 1, 400 96 Ústí nad Labem, Czech Republic;
| | - Robert Klie
- Department of Physics, The University of Illinois at Chicago, Chicago, IL 60607, USA;
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Lavrentiev V, Motylenko M, Barchuk M, Schimpf C, Lavrentieva I, Pokorný J, Röder C, Vacik J, Dejneka A, Rafaja D. Structure assembly regularities in vapour-deposited gold-fullerene mixture films. Nanoscale Adv 2020; 2:1542-1550. [PMID: 36132301 PMCID: PMC9418758 DOI: 10.1039/d0na00140f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 02/21/2020] [Indexed: 06/15/2023]
Abstract
Self-assembly is an attractive phenomenon that, with proper handling, can enable the production of sophisticated hybrid nanostructures with sub-nm-scale precision. The importance of this phenomenon is particularly notable in the fabrication of metal-organic nanomaterials as promising substances for spintronic devices. The exploitation of self-assembly in nanofabrication requires a comprehension of atomic processes creating hybrid nanostructures. Here, we focus on the self-assembly processes in the vapour-deposited Au x C60 mixture films, revealing the exciting quantum plasmon effects. Through a systematic characterization of the Au x C60 films carried out using structure-sensitive techniques, we have established correlations between the film nanostructure and the Au concentration, x. The analysis of these correlations designates the Au intercalation into the C60 lattice and the Au clustering as the basic processes of the nanostructure self-assembly in the mixture films, the efficiency of which strongly depends on x. The evaluation of this dependence for the Au x C60 composite nanostructures formed in a certain composition interval allows us to control the size of the Au clusters and the intercluster spacing by adjusting the Au concentration only. This study represents the self-assembled Au x C60 mixtures as quantum materials with electronic functions tuneable by the Au concentration in the depositing mixture.
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Affiliation(s)
- V Lavrentiev
- NS Lab, Nuclear Physics Institute CAS Rez-130, Husinec 25068 Czech Republic
| | - M Motylenko
- Institute of Materials Science, TU Bergakademie Freiberg Gustav-Zeuner-Str. 5 D-09599 Freiberg Germany
| | - M Barchuk
- Institute of Materials Science, TU Bergakademie Freiberg Gustav-Zeuner-Str. 5 D-09599 Freiberg Germany
| | - C Schimpf
- Institute of Materials Science, TU Bergakademie Freiberg Gustav-Zeuner-Str. 5 D-09599 Freiberg Germany
| | - I Lavrentieva
- NS Lab, Nuclear Physics Institute CAS Rez-130, Husinec 25068 Czech Republic
| | - J Pokorný
- Institute of Physics CAS Na Slovance 2 Prague 18221 Czech Republic
| | - C Röder
- Institute of Theoretical Physics, TU Bergakademie Freiberg Leipziger Str. 23 D-09599 Freiberg Germany
| | - J Vacik
- NS Lab, Nuclear Physics Institute CAS Rez-130, Husinec 25068 Czech Republic
| | - A Dejneka
- Institute of Physics CAS Na Slovance 2 Prague 18221 Czech Republic
| | - D Rafaja
- Institute of Materials Science, TU Bergakademie Freiberg Gustav-Zeuner-Str. 5 D-09599 Freiberg Germany
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Lavrentiev V, Chvostova D, Motylenko M, Vacik J, Rafaja D, Dejneka A. Quantum plasmon excitations in gold-fullerene mixture films. Nanotechnology 2019; 30:365001. [PMID: 31151131 DOI: 10.1088/1361-6528/ab2613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Controllable access to the hybrid plasmonic nanostructures built of small metal nanoparticles and organic spacer offers a tempting set of electronic excitations, which proper handling promises valuable applications and bright fundamental prospect. Here, we report on remarkable plasmonic properties of the Au x C60 hybrid nanostructures formed through self-assembling the depositing mixture of metal and fullerene. Using optical absorption spectra, we demonstrate establishing of quantum plasmon (QP) excitations upon the controllable increase of spatial density and size of the Au clusters formed in the films. Detection of two plasmonic modes evidences the QP hybridization enabling by nm-scaled proximity of the neighboured Au clusters. Variation of the QP mode parameters with gradual decrease of the inter-cluster spacing ΔL to the sub-nanometre scale driven by the Au concentration in the film x allowed us to evidence the quantum tunnelling regime in the QP hybridization launching at ΔL ≈ 0.9 nm. The later result designates an important role of the C60 molecules, separating the Au clusters, in design of plasmonic and transport properties of the hybrid films. The obtained results represent the self-assembled Au x C60 nanocomposites as the promising plasmonic materials with potential for application in nanoplasmonics, nanoelectronics, and nanomedicine.
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Affiliation(s)
- Vasily Lavrentiev
- Nuclear Physics Institute CAS, Rez-130, Husinec 25068, Czech Republic
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Lavrentiev V, Chvostova D, Stupakov A, Lavrentieva I, Vacik J, Motylenko M, Barchuk M, Rafaja D, Dejneka A. Quantum plasmon and Rashba-like spin splitting in self-assembled Co x C 60 composites with enhanced Co content (x > 15). Nanotechnology 2018; 29:135701. [PMID: 29368694 DOI: 10.1088/1361-6528/aaaa7a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Driving by interplay between plasmonic and magnetic effects in organic composite semiconductors is a challenging task with a huge potential for practical applications. Here, we present evidence of a quantum plasmon excited in the self-assembled Co x C60 nanocomposite films with x > 15 (interval of the Co cluster coalescence) and analyse it using the optical absorption (OA) spectra. In the case of Co x C60 film with x = 16 (LF sample), the quantum plasmon generated by the Co/CoO clusters is found as the 1.5 eV-centred OA peak. This finding is supported by the establishment of four specific C60-related OA lines detected at the photon energies E p > 2.5 eV. Increase of the Co content up to x = 29 (HF sample) leads to pronounced enhancement of OA intensity in the energy range of E p > 2.5 eV and to plasmonic peak downshift of 0.2 eV with respect to the peak position in the LF spectrum. Four pairs of the OA peaks evaluated in the HF spectrum at E p > 2.5 eV reflect splitting of the C60-related lines, suggesting great change in the microscopic conditions with increasing x. Analysis of the film nanostructure and the plasmon-induced conditions allows us to propose a Rashba-like spin splitting effect that suggests valuable sources for spin polarization.
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Affiliation(s)
- Vasily Lavrentiev
- Nuclear Physics Institute of the Czech Academy of Sciences, Rez-130, Husinec 25068, Czechia
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Lavrentiev V, Stupakov A, Lavrentieva I, Motylenko M, Barchuk M, Rafaja D. Evidence of interface exchange magnetism in self-assembled cobalt-fullerene nanocomposites exposed to air. Nanotechnology 2017; 28:125704. [PMID: 28145895 DOI: 10.1088/1361-6528/aa5d73] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report on the establishing of an exclusive magnetic effect in air-exposed CoxC60 nanocomposites (x > 2) created through self-assembling in the depositing mixture. In order to verify the influence of ambient air on the CoxC60 mixture film, we have studied in detail the film magnetization at rather low temperatures, which provides their ferromagnetic behavior. Tracing the possible exchange bias effect, we distinguished a clear vertical shift of the hysteresis loops recorded for the air-exposed CoxC60 films in the field cooling (FC) regime. The detected vertical shift of the FC loops is caused by an uncompensated magnetic moment M u induced by exchange coupling of the Co spins at the Co/CoO interface. This interface arises due to the oxidation of small Co clusters distributed in a C60-based matrix of self-assembled composite films, which occurs during air exposure. The core-shell structure of the Co/CoO magnetic clusters (about 2-3 nm in size) consisting of a ε-Co core and fcc-CoO shell was confirmed by means of transmission electron microscopy. Established interface magnetism testifies to a composite nanostructure in the CoxC60 mixture film with x > 2 and explains the influence of air exposure on the film structure. The discovered magnetic effect implies a new application potential for cobalt-fullerene composites in sensors and catalysis.
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Affiliation(s)
- V Lavrentiev
- Nuclear Physics Institute CAS, Rez-130, Husinec 25068, Czechia
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Lavrentiev V, Vacik J, Dejneka A, Jastrabik L, Vorlicek V, Chvostova D, Potucek Z, Narumi K, Naramoto H. Functionalization of silicon crystal surface by energetic cluster ion bombardment. J Nanosci Nanotechnol 2012; 12:9136-9141. [PMID: 23447968 DOI: 10.1166/jnn.2012.6782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report the creation of a functional nanostructure on a Si crystal surface by 200 keV C60(++) cluster ion bombardment (CIB). We found that the modified layer produced by CIB includes two sublayers with different nanostructures. The top 24-nm-thick sublayer is an agglomeration of 5-nm-sized amorphous Si nanodots (a-Si NDs). The deeper 10-nm-thick sublayer is a transient layer of disordered Si as an interface between the a-Si top sublayer and the bulk Si(100). The top a-Si sublayer and the nc-Si transient layer are formed by the local heating effect and shock wave effect, respectively, induced by the cluster ion impacts. The photoluminescence (PL) spectra of the CIB-modified Si samples revealed an emission line centered at a photon energy of 1.92 eV. The absorption spectra of the modified samples exhibit enhanced light absorption at this photon energy. The parameters of the PL line require ascribing the emission origin to the quantum-confinement-induced optical transitions in the a-Si nanodots. The core-shell structure of a-Si NDs is confirmed by detection of an additional PL line centered at 2.5 eV. Analysis of the Rutherford backscattering (RBS) and the PL spectra implies the existence of -Si--O- bonds in the nanodot outer shells, which are responsible for the additional PL line. The obtained results demonstrate the valuable potential of CIB for the controllable fabrication of Si surface nanostructures, which is attractive for optoelectronics and nanoelectronics. The obtained results elucidate the evolution of structure modification occurring in silicon due to the injection of energetic C60 cluster ions with an energy of hundreds of keV.
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Affiliation(s)
- Vasily Lavrentiev
- NS Lab, Nuclear Physics Institute AS CR, Rez-130, Husinec 250 68, Czech Republic
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Lavrentiev V, Vacik J, Naramoto H, Sakai S. Thermal effect on structure organizations in cobalt-fullerene nanocomposition. J Nanosci Nanotechnol 2010; 10:2624-2629. [PMID: 20355474 DOI: 10.1166/jnn.2010.1391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Effect of deposition temperature (Ts) on structure of Co-C60 nanocomposite (NC) prepared by simultaneous deposition of cobalt and fullerene on sapphire is presented. The NC structure variations with Ts increasing from room temperature (RT) to 400 degrees C have been analyzed using scanning electron microscopy (SEM), atomic force microscopy (AFM) and Raman spectroscopy. AFM and SEM show granule-like structure of the Co-C60 film. The mixture film deposited at RT includes the hills on the surface suggesting accumulation of internal stress during phase separation. Raman spectra show 25 cm(-1) downshift of Ag(2) C60 peak suggesting -Co-C60- polymerization in C60-based matrix of the NC film. Analysis of Raman spectra has revealed existence of amorphous carbon (a-C) in the NC matrix that argues C60 decomposition. The Ts increase to 200 degrees C causes the surface hills smoothing. In parallel, downshift of the Ag(2) peak decreases to 16 cm(-1) that implies more pronounced phase separation and lower -Co-C60- polymerization efficiency. Also, amount of a-C content slightly increases. Further Ts increasing to 400 degrees C changes the NC structure dramatically. AFM shows evident enlargement of the granules. According to Raman spectra the high Ts deposition yields pronounced C60 decomposition increasing the a-C content. Features of a-C Raman peak imply nucleation of graphitic islands at the NC interfaces. Abundant decomposition of C60 in the mixture film deposited at 400 degrees C is referred to cobalt catalytic effect.
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Affiliation(s)
- Vasily Lavrentiev
- Nuclear Physics Institute AS CR, 250 68 Husinec-Rez 130, Czech Republic
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Lavrentiev V, Vacik J, Naramoto H, Sakai S. Self-assembling hybrid nanoparticles during simultaneous deposition of Co and C60 on sapphire. J Nanosci Nanotechnol 2009; 9:4305-4310. [PMID: 19916447 DOI: 10.1166/jnn.2009.m50] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The Co-C60 nano-composite film prepared by simultaneous deposition of Co and C60 at room temperature (RT) on sapphire with high content of cobalt (50 at.% Co) is recognized as ensemble of the fcc-Co crystals (5-6 nm in size) separated by the C60-based matrix. It is shown formation of internal stress in the composition arising due to the phase separation. The internal stress causes the phenomena sufficiently influencing structure of the nano-composite. One of them is locking the Co atoms within the C60-based matrix (retained Co atoms) occurring during the separation process. Analysis of the Raman spectrum argues that the retained Co atoms are included in the Co-C60 polymer dominating in the matrix of nano-composite. It is suggested importance of the internal stress for the polymer formation. Another phenomenon is the structural relaxation releasing the internal stress. These phenomena are tested through applying different thermal treatments. Raman spectrum of the mixture film deposited at 200 degrees C shows the lower polymerization efficiency in the C60-based matrix due to the more complete phase separation decreasing number of the retained Co atoms. Post-deposition annealing of the RT-deposited Co-C60 mixture film done at 300 degrees C for 1 hour induces the structural relaxation as conversion of fullerene into the regular carbon structure. According to the Raman analysis the regular carbon structure corresponds to the single-wall carbon nanotubes (SWNT) doped by cobalt. Similar analysis of the 200 degrees C-deposited mixture film treated by the following annealing reveals formation of SWNT only after much longer annealing. These experiments designate the Co diffusion as a main process driven by the carbon nanotube formation. The results demonstrate remarkable opportunity to control structure of the Co-C60 nano-composite using proper thermal treatments.
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Affiliation(s)
- Vasily Lavrentiev
- Nuclear Physics Institute AS CR, 250 68 Husinec-Rez 130, Czech Republic
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Avramov P, Naramoto H, Sakai S, Narumi K, Lavrentiev V, Maeda Y. Quantum Chemical Study of Atomic Structure Evolution of Cox/C60 (x ≤ 2.8) Composites. J Phys Chem A 2007; 111:2299-306. [PMID: 17388319 DOI: 10.1021/jp0655874] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The main features of the local atomic structure of novel Cox/C60 (x<or=2.8) complex mixtures were studied using the ab initio B3LYP/6-31G* method for a set of low- and high-energy Con(C60)m (n=1, 2, m=2, 3) clusters in low and intermediate spin states. For the n = 1 isomers the spin state S=1/2 is energetically preferable, whereas the low-energy isomers of n=2 have an intermediate spin state of S=1. The eta2 (6-6 edge of C60) type of cobalt ion coordination is preferable for both the n=1 and n=2 cases. The eta2' (coordination with a 6-5 edge) and even the eta5 (C5 fragment) types can serve as low- and high-energy intermediates for the cobalt ion's migration around the C60 cage. Formation of cobalt dimers can be the final stage of evolution of Cox/C60 atomic structure approaching the equilibrium atomic geometry.
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Affiliation(s)
- Pavel Avramov
- Takasaki-Branch, Advanced Science Research Center, Japan Atomic Energy Agency, Takasaki, 370-1292, Japan.
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