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1.
This review is focused on charge-transfer reactions at carbon nanotubes and fullerenes. The spectroelectrochemistry of fullerenes deals with the spin states of fullerenes, the role of mono-anions and the reactivity of higher charged states in C60. The optical (Vis-NIR) spectroelectrochemistry of single-walled carbon nanotubes (SWNTs) follows changes in the allowed optical transitions among the Van Hove singularities. The Raman spectroelectrochemistry of SWNT benefits from strong resonance enhancement of the Raman scattering. Here, both semiconducting and metallic SWNTs are analyzed using the radial breathing mode (RBM) and G-modes as well as the second order (D, G') and intermediate frequency modes. Raman spectroelectrochemistry of SWNT allows the addressing of index-identified tubes and even single isolated nanotubes. Optical and Raman spectroelectrochemistry of fullerene peapods, C60@SWNT and C70@SWNT indicates effective shielding of the intratubular fullerene (peas). The most striking effect in the spectroelectrochemistry of peapods is the so-called "anodic Raman enhancement" of intratubular C60. Double-walled carbon nanotubes (DWNTs) give a specific spectroscopic response in Vis-NIR spectroelectrochemistry for the inner and the outer tube. They are better distinguishable by Raman spectroelectrochemistry which allows a precise tracing of the specific doping response of outer/inner tubes. 相似文献
2.
Dr. Martin Kalbáč Prof. Ladislav Kavan Sandeep Gorantla Dr. Thomas Gemming Prof. Dr. Lothar Dunsch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(38):11753-11759
The interaction of single‐walled carbon nanotubes (SWCNTs) and α‐sexithiophene (6T) was studied by Raman spectroscopy and by in situ Raman spectroelectrochemistry. The encapsulation of 6T in SWCNT and its interaction causes a bleaching of its photoluminescence, and also small shifts of its Raman bands. The Raman features of the SWCNT with embedded 6T (6T‐peapods) change in both intensity and frequency compared to those of pristine SWCNT, which is a consequence of a change of the resonant condition. Electrochemical doping demonstrated that the electrode potential applied to the SWCNT wall causes changes in the embedded 6T. The effects of electrochemical charging on the Raman features of pristine SWCNT and 6T@SWCNT were compared. It is shown that the interaction of SWCNT with 6T also changes the electronic structure of SWCNT in its charged state. This change of electronic structure is demonstrated both for semiconducting and metallic tubes. 相似文献
3.
Kalbác M Kavan L Zukalová M Yang S Cech J Roth S Dunsch L 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(31):8811-8817
Raman and in situ Raman spectroelectrochemical studies of Dy3N@C80@SWCNT peapods have been carried out for the first time. The formation of peapods by the encapsulation of gaseous Dy3N@C80 has been confirmed by HR-TEM microscopy and by the successful transformation of Dy3N@C80@SWCNT into double-walled carbon nanotubes. The Raman spectra of the endohedral fullerene cluster changed dramatically in the interior of the single-walled carbon nanotube (SWCNT). The electrochemical charging of the peapod indicates a slight reversible attenuation of the Raman intensities of fullerene features during anodic doping. The results support the assignment of Raman bands to the Dy3N@C80 moiety inside a SWCNT. 相似文献
4.
Hybrids of Copolymers of Fluorene and C60‐Carrying‐Carbazole with Semiconducting Single‐Walled Carbon Nanotubes
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Fumiyuki Toshimitsu Hiroaki Ozawa Prof. Naotoshi Nakashima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3359-3366
Three different copolymers of C60‐carrying‐carbazole and fluorene units with different copolymer composition ratios were designed and synthesized. On the basis of photoluminescence, atomic force microscopy, and Vis‐NIR and Raman spectroscopic analysis, we found that these copolymers solubilize only semiconducting single‐walled carbon nanotubes (sem‐SWNTs) to form copolymer/sem‐SWNT hybrids, in which energy transfer from the copolymer/C60 moieties to the SWNTs was revealed. By comparing two possible hybrid structures with molecular‐mechanics simulations, the greatest stabilization was found when the C60 moieties lay on the sem‐SWNT surfaces. 相似文献
5.
Peter Hammershøj Paul H. H. Bomans Dr. Rajamani Lakshminarayanan Jeppe Fock Stig Helmer Jensen Thomas Sand Jespersen Theis Brock‐Nannestad Tue Hassenkam Prof. Jesper Nygård Prof. Nico A. J. M. Sommerdijk Prof. Kristine Kilså Prof. Thomas Bjørnholm Dr. Jørn Bolstad Christensen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(28):8716-8723
We describe herein the synthesis of a triptycene‐based surfactant designed with the ability to solubilise single‐walled carbon nanotubes (SWNTs) and C60 in water through non‐covalent interactions. Furthermore, an amphiphilic naphthalene‐based surfactant with the same ability to solubilise SWNTs and C60 has also been prepared. The compounds synthesised were designed with either two ionic or non‐ionic tails to ensure a large number of supramolecular interactions with the solvent, thereby promoting strong solubilisation. The surfactants produced stable suspensions in which the SWNTs are dispersed and the surfactant/SWNT complexes formed are stable for more than one year. UV/Vis/NIR absorption spectroscopy, TEM and AFM were employed to probe the solubilisation properties of the dispersion of surfactants and SWNTs in water. 相似文献
6.
Kalbác M Kavan L Zukalová M Dunsch L 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(20):6231-6236
Raman spectroscopy and in situ Raman spectroelectrochemistry have been applied to the study of the lithium vapor doping of C60@SWCNTs (peapods; SWCNT=single-walled carbon nanotube). A strong degree of doping was proven by the disappearance of the radial breathing mode (RBM) of the SWCNTs and by the attenuation of the tangential (TG) band intensity by two orders of magnitude. The lithium doping causes a downshift of the Ag(2) mode of the intratubular C60 by 27 cm(-1) and changes the resonance condition of the encapsulated fullerene. In contrast to potassium vapor doping, the strong downshift of the TG band was not observed for lithium doping. The peapods treated with lithium vapor remained partially doped even when they were exposed to humid air. This was reflected by a reduction in the intensity of the nanotube and the fullerene modes and by the change in the shape of the RBM band compared with that of the undoped sample. The Ag(2) mode of the intratubular fullerene was not resolved after contact of the lithium-doped sample with water. Lithium insertion into the interior of a peapod and its strong interaction with the intratubular fullerene is suggested to be responsible for the air-insensitive residual doping. This residual doping was confirmed by in situ spectroelectrochemical measurements. The TG band of the lithium-doped peapods did not undergo an upshift during the anodic doping, which points to the formation of a stable exohedral metallofullerene peapod. 相似文献
7.
L. Hechavarría H. Hu M. Miranda M. E. Nicho 《Journal of Solid State Electrochemistry》2009,13(5):687-695
Thin films of tungsten trioxide (WO3) for electrochromic application were synthesized by potentiostatic method by using a peroxytungstic acid as a solution precursor.
The morphology of the films with and without postthermal annealing was analyzed by atomic force microscopy. When they were
in contact with the liquid electrolyte (LiI in propylene carbonate, PC) and under alternatively applied negative (−1.5 V)
and positive (+1.0 V) potentials, the transient optical transmittance modulations at wavelength of 650 nm of the as-deposited
and 60 °C annealed WO3 samples were higher than that of 100 °C annealed WO3 films, and the switching times between the colored and bleached states were related to the surface morphology of the WO3 films. In polymeric gel electrolyte (LiI and polymethyl methacrylate in PC) devices, longer time was required for complete
coloration as well as bleaching process compared with the liquid one. A parametric analysis was made for each of the transient
optical transmittance curves of WO3-based electrochromic devices to extract the values of the response time in coloration (reduction) and bleaching (oxidation)
processes. It concludes that the coloration process was determined by the exchange of current density at the electrolyte–WO3 interface and a possible inhomogeneous interfacial potential for ion intercalation retards the effective coloration time.
The bleaching process seems to be controlled by the space charge-limited lithium ion diffusion in WO3 electrode and the ionic conductivity of the electrolyte as well. 相似文献
8.
The state of doping of fullerene peapods C60@SWCNT treated with K vapor was studied by in situ Raman spectroelectrochemistry. For all samples under study, a heavy chemical n doping was proved by the vanishing of the radial breathing mode and the downshift of tangential displacement mode. The K-treated peapods remain partly doped even if they are exposed to humid air. The Ag(2) mode of intratubular fullerene in K-doped peapods in contact with air was still redshifted as referred to its position in pristine peapods. Potassium inserted into the peapods is the reason for the air-insensitive residual doping, which can be removed only by electrochemical oxidation. This indicates the presence of two positions of potassium in doped sample. 相似文献
9.
The application of in situ ESR–UV/VIS/NIR spectroelectrochemistry to the highly purified C82:3 fullerene isomer with C2 symmetry made the detailed characterization of the radical structures formed by electrochemical generation possible. This first comprehensive spectroelectrochemical study of the stable radical anion and cation of an empty cage higher fullerene in acid-free organic electrolyte is a contribution to the general understanding of charged states at endohedral fullerenes. 相似文献
10.
Single‐Walled Carbon Nanotubes in Highly Viscous Media: A Comparison between the Dispersive Agents [BMIM][BF4], L121, and Triton X‐100
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Dr. Carla Gasbarri Prof. Fausto Croce Dr. Ida Meschini Christopher H. Bowen Dr. Lisa Marinelli Prof. Antonio Di Stefano Dr. Guido Angelini 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(2):546-549
Dispersions of single‐walled carbon nanotubes (SWNTs) have been prepared by using the room‐temperature ionic liquid [BMIM][BF4] (1‐butyl‐3‐methylimidazolium tetrafluoroborate), the triblock copolymer Pluronic L121 [poly(ethylene oxide)5‐poly(propylene oxide)68‐poly(ethylene oxide)5] and the non‐ionic surfactant Triton X‐100 (TX100) in the pure state. The size of the SWNTs aggregates and the dispersion degree in the three viscous systems depend on the sonication time, as highlighted by UV/Vis/NIR spectroscopy and optical microscopy analysis. A nonlinear increase in conductivity can be observed as a function of the SWNTs loading, as suggested by electrochemical impedance spectroscopy. The generation of a three‐dimensional network of SWNTs showing a viscoelastic gel‐like behavior above a critical percolation concentration has been found at 25 °C in all the investigated systems by oscillatory rheology measurements. 相似文献
11.
Kalbac M Kavan L Zukalová M Dunsch L 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(16):4451-4457
The intermediate frequency modes (IFM) of single-walled carbon nanotubes (SWCNTs) and double-walled carbon nanotubes (DWCNTs) were analyzed by Raman spectroscopy and in situ Raman spectroelectrochemistry. The inner and outer tubes of DWCNTs manifested themselves as distinct bands in the IFM region. This confirmed the diameter dependence of IFM frequencies. Furthermore, the analysis of inner tubes of DWCNTs allowed a more-precise assignment of the bands in the IFM region to features intrinsic for carbon nanotubes. Although the inner tubes in DWCNTs are assumed to be structurally perfect, the role of defects on IFM was discussed. The dependence of IFM on electrochemical charging was also studied. In situ spectroelectrochemical data provide a means to distinguish the bands of the outer and inner tubes. 相似文献
12.
《Electrochemistry communications》2007,9(2):255-261
The spectral changes occurring in multilayer films of hexanethiolate monolayer-protected Au147 clusters (C6–Au147 MPCs) as a consequence of quantized MPC core charging have been investigated in aqueous solutions using a multiresponse technique, UV–vis reflectance spectroelectrochemical quartz crystal microbalance (SEQCM). The joint technique, a combination of UV–vis near-normal incidence reflectance spectroelectrochemistry and electrochemical quartz crystal microbalance, has enabled us to follow both reflectance and gravimetric changes taking place in the MPC film concurrently with each single electron transfer event. Reversible film reflectance drops were observed upon anodic MPC charging, which were linearly dependent on the MPC charge state. The values of the formal potential and number of electrons transferred in each charging step, determined from the potential dependence of the reflectance changes, proved that the spectral features were induced by the discrete charging of the MPCs. Simultaneously, the gravimetric signal monitored with EQCM yielded values of the number of MPC-bound electrolyte ions as a function of the MPC redox state, both during voltammetric and potential step charging of the MPC films. Additionally, the dynamics of electron transfers in these multilayer MPC films has been investigated by electrochemical impedance spectroscopy (EIS). Thus, the film capacitance, the resistance to charge transfer, and the electron-transfer rate constant for MPC oxidation have been estimated. 相似文献
13.
Thermally stable, flexible polymer gel electrolytes with high ionic conductivity are prepared by mixing the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (C4mpyrTFSI), LiTFSI and poly(vinylidene difluoride-co-hexafluoropropylene (PVDF-HFP). FT-IR and Raman spectroscopy show that an amorphous film is obtained for high (60 %) C4mpyrTFSI contents. Thermogravimetric analysis (TGA) confirms that the polymer gels are stable below ∼300 °C in both nitrogen and air environments. Ionic conductivity of 1.9×10−3 S cm−2 at room temperature is achieved for the 60 % ionic liquid loaded gel. Germanium (Ge) anodes maintain a coulombic efficiency above 95 % after 90 cycles in potential cycling tests with the 60 % C4mpyrTFSI polymer gel. 相似文献
14.
豆荚型纳米材料C60@SWNTs的制备和表征 总被引:1,自引:0,他引:1
通过气相扩散的方法将C60填入单壁碳纳米管(SWNTs),制备了豆荚型纳米材料C60@SWNTs,并利用高分辨电子显微镜(HRTEM)和拉曼光谱(Raman spectra)对其进行了表征.结果均证明C60以较高的比例填充入单壁碳纳米管中.HRTEM结果表明,填入单壁碳纳米管的C60之间的距离与面心立方C60晶体中C60之间的距离有细微的差别,说明C60分子与SWNTs间存在弱的范德华相互作用.此外,还观察到在电子束的照射下,C60在SWNT中两两聚合的现象. 相似文献
15.
Zhen Liu Sherif Zein El Abedin Frank Endres 《Journal of Solid State Electrochemistry》2014,18(10):2683-2691
In this paper, we report on zinc deposition and stripping in an ionic liquid polymer gel electrolyte on gold and copper substrates, respectively. The ionic liquid-based polymer gel electrolyte is prepared by combining the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate ([Py1,4]TfO), with Zn(TfO)2 and poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP). The ionic liquid polymer gel electrolyte exhibits good conductivity (2.2 mS cm?1) and good mechanical stability. Zinc deposition and stripping in the ionic liquid polymer gel electrolyte were studied by cyclic voltammetry, potentiostatic, and galvanostatic cycling (charging/discharging) experiments. The gel electrolyte exhibits a promising electrochemical stability and allows a quasi-reversible zinc deposition/stripping. The morphology of the zinc deposits after 10 cycles of zinc deposition/stripping is compact and dense, and deposits without any dendrite formation can be obtained. The quasi-reversibility of the electrochemical deposition/stripping of zinc in this ionic liquid polymer gel electrolyte is of interest for rechargeable zinc-based batteries. 相似文献
16.
Markéta Zukalová Ján Tarábek Martin Kalbáč Ladislav Kavan Lothar Dunsch 《Journal of Solid State Electrochemistry》2008,12(10):1279-1284
A detailed study is presented on the optical absorption of thin films of single-walled carbon nanotubes (SWNT) under electrochemical
conditions. The procedure for the preparation of free-standing semitransparent films of SWNT is used for the fabrication of
a working electrode for transmission optical spectroelectrochemistry. The analysis of the potential dependent spectroscopic
response of the SWNT film benefits from the widest possible electrochemical window, in which the charging of SWNT can safely
be investigated. This electrochemical window is not limited by parasitic electrochemistry and/or galvanic breakdown reactions
occurring at supporting electrode materials such as indium–tin oxide conducting glass or semitransparent Pt film, which were
employed in earlier studies. Electrochemical doping of SWNT is observable at the optical absorptions, which are assigned to
allowed electronic transitions between van Hove singularities in the density of states of SWNT. Furthermore, the spectral
response of counterions, balancing the charging of the nanotube skeleton, is traceable at certain conditions. The latter effect
is monitored here through the overtones of C–H stretching vibrations from tetrabutylammonium cations. 相似文献
17.
A. Atyaoui H. Cachet E. M. M. Sutter L. Bousselmi 《Surface and interface analysis : SIA》2013,45(11-12):1751-1759
This work compares the behaviors of TiO2 nanotube (TNTs) array obtained by anodization of Ti foils in an ethylene glycol/NH4F/water electrolyte with different applied voltages during a constant anodization time, and for the same electrolyte composition. The crystal structure and surface morphology of the annealed anodic films are investigated by X‐Ray diffraction system, Raman spectroscopy and scanning electron microscopy, respectively. The TiO2 nanotubes obtained at potentials of 20–40–60 V show different inner diameters (42–89–124 nm), tube length (1.2–3.3–12.7 µm) and wall thicknesses (12–15–18 nm). The influence of these geometric parameters on the photoelectrochemical properties and the photocatalytic activity were investigated in detail. The results showed that the photocatalytic performances of TNT films are improved when the specific surface, the tube length and the solid fraction are increased, but the increase is slowed down when a limiting thickness of the layer is reached. The surface states which usually show high density in nanostructured layers do not seem to influence significantly the photocatalytic activity of the layers. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
18.
Dr. Laura Rodríguez‐Pérez Dr. Raúl García Dr. María Ángeles Herranz Prof. Dr. Nazario Martín 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(24):7278-7286
A complementary double‐covalent functionalization of single‐wall carbon nanotubes (SWCNTs) that involves both solubilizing ionic liquids and electroactive moieties is reported. Our strategy is a simple and efficient methodology based on the stepwise functionalization of the nanotube surface with two different organic moieties. In a first instance, oxidized SWCNTs are amidated with ionic liquid precursors, and further treated with n‐butyl bromide to afford SWCNTs functionalized with 1‐butylimidazolium bromide. This approach allows tuneable polarity induced by anion exchange, which has an effect on the relative solubility of the modified SWCNTs in water. Subsequently, a 1,3‐dipolar cycloaddition reaction was performed to introduce the electron‐acceptor 11,11,12,12‐tetracyano‐9,10‐anthra‐para‐quinodimethane (TCAQ) unit on the SWCNTs. Furthermore, to evaluate the influence of the functional group position, the TCAQ electroactive molecule was anchored through an esterification reaction onto previously oxidized SWCNTs, followed by the Tour reaction to introduce the ionic liquid functions. IR and Raman spectroscopies, thermogravimetric analysis (TGA), UV/Vis/NIR spectroscopy, transmission electron microscopy (TEM), and X‐ray photoelectron spectroscopy (XPS) were employed and clearly confirmed the double‐covalent functionalization of the SWCNTs. 相似文献
19.
Jn Tarbek Mareike Wolter Peter Rapta Waldfried Plieth Michel Maumy Lothar Dunsch 《Macromolecular Symposia》2001,164(1):219-225
The redox and optical properties of various well defined polymer and copolymer films containing pyrrole or thiophene units were studied. The in situ ESR/UV‐Vis‐NIR spectroelectrochemistry was applied to investigate polymers and copolymers deposited both electrochemically or by a special chemical procedure using adhesion promoter onto the optically transparent indium‐tin‐oxide (ITO) electrodes. The spectroelectrochemical responses of chemically and electrochemically prepared polythiophenes on ITO were compared and the electronic structures of both polymers found to be similar. In situ ESR/UV‐Vis‐NIR voltammetric studies on electrochemically prepared copolymers containing pyrrole units and various N,N′‐ethylene‐bis(salicylidenimine) (salen) transition metal complexes indicate the presence of both polysalen and polypyrrole redox active centers in the copolymer. 相似文献
20.
《Electroanalysis》2006,18(17):1681-1688
Acidic treated multiwalled carbon nanotubes (AMWNTs) were ground with water‐miscible room temperature ionic liquids, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([bmim]BF4), and resulted in AMWNTs‐[bmim]BF4 composite. Its electrical‐ionic conductivity and optical properties were compared with the other two types of carbon materials‐[bmim]BF4 composites: pyrolytic graphite powder (PGP), pristine multiwalled carbon nanotubes (PMWNTs), through the ac impedance technology and Raman spectroscopy. The impedance data show that AMWNTs‐[bmim]BF4 composite exhibits the highest conductivity. Raman spectra study exhibits that the [bmim]BF4 can form gel with PMWNTs and AMWNTs but only form a viscous liquid with PGP. AMWNTs‐[bmim]BF4 gel modified GC electrode was applied in direct electrochemistry of heme proteins (Hb and HRP) and it catalysis to the reduction of H2O2 was investigated. 相似文献