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Dzwilewski, Andrzej
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Publications (10 of 13) Show all publications
Dmitriev, V., Filinchuk, Y., Chernyshov, D., Talyzin, A., Dzwilewski, A., Andersson, O., . . . Kurnosov, A. (2008). Pressure-temperature phase diagram of LiBH4: Synchrotron x-ray diffraction experiments and theoretical analysis. Physical Review B, 77(17), 174112.
Open this publication in new window or tab >>Pressure-temperature phase diagram of LiBH4: Synchrotron x-ray diffraction experiments and theoretical analysis
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2008 (English)In: Physical Review B, ISSN 1098-0121, Vol. 77, no 17, 174112- p.Article in journal (Refereed) Published
Abstract [en]

An in situ combined high-temperature high-pressure synchrotron radiation diffraction study has been carried out on LiBH4. The phase diagram of LiBH4 is mapped to 10 GPa and 500 K, and four phases are identified. The corresponding structural distortions are analyzed in terms of symmetry-breaking atomic position shifts and anion ordering. Group-theoretical and crystal-chemical considerations reveal a nontrivial layered structure of LiBH4. The layers and their deformations define the structural stability of the observed phases.

Keyword
Hydrogen storage, hydrides, high pressure, phase transitions, phase diagram, lattice structures, LiBH4, X-ray diffraction, thermal conductivity, differential thermal analysis, group theory, order parameters, Landau theory
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:umu:diva-9686 (URN)doi:10.1103/PhysRevB.77.174112 (DOI)
Note
ISSN 1550-235X online. Selected as "Editor's Suggestion", as a paper of particular interest, importance, and clarity.Available from: 2008-05-20 Created: 2008-05-20 Last updated: 2011-01-10Bibliographically approved
Dzwilewski, A., Wågberg, T. & Edman, L. (2007). C60 Field-Effect Transistors: Effects of Polymerization on Electronic Properties and Device Performance.. In: Extended abstracts – 9th European Conference on Molecular Electronics. .
Open this publication in new window or tab >>C60 Field-Effect Transistors: Effects of Polymerization on Electronic Properties and Device Performance.
2007 (English)In: Extended abstracts – 9th European Conference on Molecular Electronics, 2007Conference paper, Published paper (Other academic)
Identifiers
urn:nbn:se:umu:diva-6610 (URN)
Available from: 2007-12-15 Created: 2007-12-15Bibliographically approved
Dzwilewski, A., Wågberg, T. & Edman, L. (2007). C60 Field-Effect Transistors: Effects of Polymerization on electronic Properties and Device Performance.. Physical Review B, 75(7), 075203.
Open this publication in new window or tab >>C60 Field-Effect Transistors: Effects of Polymerization on electronic Properties and Device Performance.
2007 (English)In: Physical Review B, Vol. 75, no 7, 075203- p.Article in journal (Refereed) Published
Abstract [en]

We have investigated thin-film field-effect transistors (TFTs) with C60 as the active material, and we report the effects of photo-induced polymerization of the C60 film. We find that the effects of a complete polymerization for a typical top-contact C60 TFT is as follows: the electron mobility (μn) at room temperature drops slightly from 0.074 to 0.068 cm2/Vs, the activation energy of μn decreases from 0.10 meV to 0.09 meV, and the threshold voltage for TFT operation decreases markedly by ~15 %. The latter observation suggests that the effective number of electron traps in the C60 film decreases following polymerization. Considering that the polymerization was achieved with a low-energy HeNe laser, it is conceivable that the polymerization approach could be of interest for applications, e.g., organic bulk-heterojunction solar cells, where a stabilized C60 morphology attained with benign means is desired

Identifiers
urn:nbn:se:umu:diva-11904 (URN)
Available from: 2007-12-13 Created: 2007-12-13 Last updated: 2011-01-11Bibliographically approved
Dzwilewski, A., Talyzin, A., Bromiley, G., Dub, S. & Dubrovinsky, L. (2007). Characterization of phases synthesized close to the boundary of C60 collapse at high temperature high pressure conditions. Diamond and related materials, 16(8), 1550-1556.
Open this publication in new window or tab >>Characterization of phases synthesized close to the boundary of C60 collapse at high temperature high pressure conditions
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2007 (English)In: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 16, no 8, 1550-1556 p.Article in journal (Other (popular science, discussion, etc.)) Published
Abstract [en]

Two sets of samples were synthesized at high pressure high temperature conditions in the P-T region where C-60 molecules collapse into a nearly amorphous graphite-like hard carbon phase. For the first set, heating temperature was varied at fixed pressure and preparation time. For the second set, synthesis time was varied at fixed pressure and fixed temperature. Detailed structural characterization of samples was performed using Raman spectroscopy and powder XRD. Mechanical properties of the samples have been studied by nanoindentation method. It has been found that duration of heat treatment under high pressure is an important parameter which influences the temperature of fullerene cage collapse. Both tetragonal and rhombohedral polymeric phases transform into hard carbon phase over a rather narrow temperature interval, but the tetragonal phase shows somewhat increased stability against C-60 collapse. Viscoelastic mechanical behavior during nanoindentation was observed for fullerene polymers but not for graphite-like hard carbon phase. Possible mechanism for nucleation of the hard carbon phase in polymeric C-60 networks is discussed.

National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:umu:diva-18180 (URN)10.1016/j.diamond.2006.12.040 (DOI)
Available from: 2007-11-28 Created: 2007-11-28 Last updated: 2017-12-14Bibliographically approved
Talyzin, A. V. & Dzwilewski, A. (2007). Ferromagnetism in C60 polymers: pure carbon or contamination with metallic impurities?. J Nanosci Nanotechnol, 7(4-5), 1151-61.
Open this publication in new window or tab >>Ferromagnetism in C60 polymers: pure carbon or contamination with metallic impurities?
2007 (English)In: J Nanosci Nanotechnol, ISSN 1533-4880, Vol. 7, no 4-5, 1151-61 p.Article in journal (Refereed) Published
Abstract [en]

A review of ferromagnetism in C-60 polymeric materials synthesized by high pressure high temperature (HPHT) treatment is presented. Analysis of published data proves that the reported ferromagnetism cannot be assigned to polymeric structure in either perfect or defect states. Most recent experimental studies have not confirmed previously reported levels of magnetization in polymeric samples while it appears that ferromagnetism of "magnetic carbon" is preserved above the depolymerization point of any C-60 polymer. Identical ferromagnetic properties in some samples of fullerene polymer and graphite like hard carbon phase also show that the effect is most likely not connected to fullerenes at all. Most of the data published previously as an evidence of ferromagnetism in C-60 polymers synthesized at HPHT conditions can be explained by contamination with magnetic impurities. Formation of iron carbide (Fe3C) due to reaction of metallic iron with fullerene molecules allows to explain observed Curie temperature of similar to 500 K and levels of magnetization reported for ''magnetic carbon."

Keyword
Carbon/chemistry, Chemistry; Physical/methods, Electrons, Fullerenes/*chemistry, Hydrogen/chemistry, Iron Compounds/chemistry, Magnetics, Metals/*chemistry, Microscopy; Electron; Transmission, Nanotechnology/instrumentation/*methods, Polymers/*chemistry, Temperature
Identifiers
urn:nbn:se:umu:diva-18178 (URN)17450884 (PubMedID)
Available from: 2007-11-28 Created: 2007-11-28 Last updated: 2011-01-11Bibliographically approved
Talyzin, A. V., Dzwilewski, A. & Pudelko, M. (2007). Formation of palladium fullerides and their thermal decomposition into palladium nanoparticles. Carbon, 45(13), 2564-2569.
Open this publication in new window or tab >>Formation of palladium fullerides and their thermal decomposition into palladium nanoparticles
2007 (English)In: Carbon, Vol. 45, no 13, 2564-2569 p.Article in journal (Refereed) Published
Abstract [en]

Formation of palladium fullerides from various Pd:C60 compositions was studied by XRD, Raman spectroscopy and TEM. Raman spectra of PdxC60 samples show close similarity to spectra of C60 polymers obtained under high pressure/high temperature conditions and suggest the formation of chain-like and two-dimensional polymeric structures in PdxC60 of various compositions. Thermal decomposition of PdxC60 results in the formation of fine 5-10 nm size nanoparticles of palladium which can be used for catalytic applications

Place, publisher, year, edition, pages
Science, 2007
Identifiers
urn:nbn:se:umu:diva-16186 (URN)doi:10.1016/j.carbon.2007.08.022 (DOI)
Note
In Press, Accepted Manuscript, Available online 23 August 2007Available from: 2007-08-28 Created: 2007-08-28 Last updated: 2011-06-15Bibliographically approved
Talyzin, A., Dzwilewski, A., Dubrovinsky, L., Setzer, A. & Esquinazi, P. (2007). Structural and magnetic properties of polymerized C60 with Fe. European Physical Journal B: Condensed Matter Physics, 55(1), 57-62.
Open this publication in new window or tab >>Structural and magnetic properties of polymerized C60 with Fe
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2007 (English)In: European Physical Journal B: Condensed Matter Physics, ISSN 1434-6028, E-ISSN 1434-6036, Vol. 55, no 1, 57-62 p.Article in journal (Refereed) Published
Abstract [en]

We provide evidence that high-pressure high-temperature (2.5 GPa and 1040 K) treatment of mixtures of iron with fullerene powders leads to the complete transformation of iron into iron carbide Fe3C. The comparison of the magnetic properties (Curie temperature and magnetic moment) of the here studied samples and those for the ferromagnetic polymer Rh-C-60 indicates that the main ferromagnetic signal reported in those samples is due to Fe3C and not related to the ferromagnetism of carbon as originally interpreted. Taking into account the results obtained in this study the original paper on "Magnetic carbon" [Nature 413, 716 (2001)] was recently retracted.

Identifiers
urn:nbn:se:umu:diva-18181 (URN)10.1140/epjb/e2007-00041-7 (DOI)
Available from: 2007-11-28 Created: 2007-11-28 Last updated: 2017-12-14Bibliographically approved
Talyzin, A., Dzwilewski, A., Sundqvist, B., Tsybin, Y., Purcell, J., Marshall, A., . . . Dubrovinsky, L. (2006). Hydrogenation of C60 at 2 GPa Pressure and High Temperature.. Chemical Physics, 325(2-3), 445-451.
Open this publication in new window or tab >>Hydrogenation of C60 at 2 GPa Pressure and High Temperature.
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2006 (English)In: Chemical Physics, ISSN 0301-0104, Vol. 325, no 2-3, 445-451 p.Article in journal (Refereed) Published
Abstract [en]

Hydrogenation of C60 at 2 GPa and 723–823 K was performed with thermal decomposition of LiAlH4 as a hydrogen source. Analysis

of hydrogenation products showed that the method can produce not only C60H36, but also hydrofullerides C60Hx with 44 < x < 52.

Unlike other hydrogenation methods in which pristine C60 reacts with hydrogen, the high pressure/high temperature conditions result

first in C60 polymerization into a tetragonal phase which later reacts with hydrogen. It is suggested that hydrogen first attacks intermolecular

carbon–carbon bonds, resulting in complete depolymerization of C60 at a later stage of the hydrogenation process. This model

suggests the possibility to select starting points for hydrogenation by choosing specific polymeric structures of C60. Hydrogenated polymeric

C60 was identified as an intermediate reaction product. Characterization of highly reduced material was performed by Raman and

IR spectroscopy, X-ray diffraction, and atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass

spectrometry.

Keyword
Fullerenes, C60, hydrogenation, hydrogen compound, high pressure, high temperature, hydrofullerides, C60H36, Raman spectroscopy, IR, XRD, mass spectrometry
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:umu:diva-11900 (URN)doi:10.1016/j.chemphys.2006.01.019 (DOI)
Available from: 2007-11-29 Created: 2007-11-29 Last updated: 2011-01-11Bibliographically approved
Shin, J.-H., Dzwilewski, A., Iwasiewicz, A., Xiao, S., Fransson, Å., Ankah, G. N. & Edman, L. (2006). Light emission at 5 V from a polymer device with a millimeter-sized interelectrode gap. Applied Physics Letters, 89, 013509.
Open this publication in new window or tab >>Light emission at 5 V from a polymer device with a millimeter-sized interelectrode gap
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2006 (English)In: Applied Physics Letters, Vol. 89, 013509- p.Article in journal (Refereed) Published
Identifiers
urn:nbn:se:umu:diva-11897 (URN)
Available from: 2007-03-15 Created: 2007-03-15 Last updated: 2011-01-11Bibliographically approved
Talyzin, A., Tsybin, Y. O. O., Purcell, J., Schaub, T., Shulga, Y. .., Noreus, D., . . . Marshall, A. (2006). Reaction of hydrogen gas with C60 at elevated pressure and temperature: Hydrogenation and cage fragmentation.. Journal of Physical Chemistry A, 110(27), 8528-34.
Open this publication in new window or tab >>Reaction of hydrogen gas with C60 at elevated pressure and temperature: Hydrogenation and cage fragmentation.
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2006 (English)In: Journal of Physical Chemistry A, ISSN 1089-5639, Vol. 110, no 27, 8528-34 p.Article in journal (Refereed) Published
Abstract [en]

Products of the reaction of C60 with H2 gas have been monitored by high-resolution atmospheric pressure

photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS), X-ray

diffraction, and IR spectroscopy as a function of hydrogenation period. Samples were synthesized at 673 K

and 120 bar hydrogen pressure for hydrogenation periods between 300 and 5000 min, resulting in the formation

of hydrofullerene mixtures with hydrogen content ranging from 1.6 to 5.3 wt %. Highly reduced C60Hx (x >

36-40) and products of their fragmentation were identified in these samples by APPI FT-ICR MS. A sharp

change in structure was observed for samples with at least 5.0 wt % of hydrogen. Low-mass (300-500 Da)

hydrogenation products not observed by prior field desorption (FD) FT-ICR MS were detected by APPI

FT-ICR MS and their elemental compositions obtained for the first time. Synthetic and analytical fragmentation

pathways are discussed.

Keyword
fullerenes, C60, hydrogen, hydrofullerenes, mass spectroscopy, synthesis, analysis, molecular breakdown, high pressure, high temperature
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:umu:diva-11903 (URN)doi:10.1021/jp0557971 (DOI)
Available from: 2007-12-12 Created: 2007-12-12 Last updated: 2011-01-11Bibliographically approved
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