Fullerene Nanotubes Research Articles

Functionalization of the Semiconductor Surfaces of Diamond (100), Si (100), and Ge (100) by Cycloaddition of Transition Metal Oxides: A Theoretical Prediction

The viability of functionalization of the semiconductor surfaces of diamond (100), Si (100), and Ge (100) by traditional [3 + 2] cycloaddition of transition metal oxides has been predicted using effective cluster models in the framework of density functional theory. The cycloaddition of transition metal oxides (OsO(4), RuO(4), and MnO(4)(-)) onto the X (100) (X = C, Si, and Ge) surface is much more facile than that of other molecular analogues including ethylene, fullerene, and single-walled carbon nanotubes because of the high reactivity of surface dimers of X (100). Our computational results demonstrate the plausibility that the well-known [3 + 2] cycloaddition of transition metal oxides to alkenes in organic chemistry can be employed as a new type of surface reaction to functionalize the semiconductor X (100) surface, which offers the new possibility for self-assembly or chemical functionalization of X (100) at low temperature. More importantly, the chemical functionalization of X (100) by cycloaddition of transition metal oxides provides the molecular basis for preparation of semiconductor-supported catalysts but also strongly advances the concept of using organic reactions to modify the solid surface, particularly to modify the semiconductor C (100), Si (100), and Ge (100) surfaces for target applications in numerous fields such as microelectronics and heterogeneous photocatalysis.

Auger investigation of fullerene nanowhiskers heat-treated at 400-800 degrees centigrade

Fullerene nanowhiskers were prepared from a toluene solution of C60 and isopropyl alcohol by a liquid-liquid precipitation method. The samples on the silicon (100) wafer were heated at the elevated temperatures ranging from 400 °C through 800 °C by an electron beam bombardment in an ultra-high vacuum, and their thermal stability was investigated with a scanning Auger-electron microprobe. At 400 °C fullerene nanowhiskers already got thinner, while bulky fullerene crystals still remained even at 800 °C. And many craters were observed around the fullerene crystals on the Si(100) substrate.

High-resolution transmission electron microscopy of heat-treated C60 nanotubes

Fullerene nanowhiskers and nanotubes are single crystals consisting of C60 molecules with a high aspect ratio of length to diameter. In this study, C60 nanowhiskers and nanotubes were heat-treated at various temperatures up to 3000 °C. The structural characteristics of the heated samples were examined using transmission electron microscopy (TEM) and Raman spectroscopy. By the high-temperature heat treatment, the C60 nanotubes turned to glassy carbon composed of randomly oriented ribbons with graphitic layers with an interlayer spacing which is close to that of the (002) planes of graphite.

Adsorption characteristics of heat-treated fullerene nano-whiskers

Fullerene nanowhiskers (FNWs) were synthesized by the liquid-liquid interfacial precipitation method and the adsorption properties of their heat-treated samples were characterized. It was found that vacuum-annealed FNWs at a high temperature are of microporous materials and, especially, ultramicropores are highly developed in these materials. Porosities even remain in samples after heat treatment at a temperature higher than 2273 K. The presence of ultramicroporosity is indicative of the molecular sieving properties of the vacuum-annealed FNW materials, suggesting the possibilities of their application as new materials for gas separation and gas storage.

Observation of phagocytosis of fullerene nanowhiskers by PMA-treated THP-1 cells

Phorbol 12-myristate 13-acetate (PMA)-treated THP-1 cells (macrophage-like cells) were exposed to the C60 fullerene nanowhiskers (C60 NWs) with an average length of about 6.0 μm and an average diameter of about 660 run and observed with an inverted optical phase-contrast microscope for 48 h. The C60 NWs were well and stably dispersed onto the dishes of culture medium during the observation. The number of cells that internalised C60 NWs gradually increased after the exposure to C60 NWs. But no alteration of cellular morphology was observed compared to the control group without exposure to C60 NWs during this period in this pilot study.

Fullerene nanowhiskers and related fullerene nanomaterials

Since the discovery of C60 nanowhiskers in a colloidal solution of PZT in 2001, various low-dimensional fullerene nanomaterials such as fullerene nanotubes and fullerene nanosheets have been synthesized by the liquid-liquid interfacial precipitation method (LLIP method) as well as the C60 and C70 nanowhiskers. The LLIP method is an excellent process to synthesize the quasi one-dimensional fullerene nanomaterials. This paper first reviews the typical fullerene nano and micro materials that have been prepared by the LLIP method and then show that the LLIP method is also applicable to the synthesis of composite C60 nano and micro whiskers containing wide compositions of C60 derivative molecules.

Synthesis and growth investigation of C60 fullerene nanowhiskers

The growth mechanism of C60 nanowhiskers (C60NWs) is investigated. The C60NWs were prepared by the liquid-liquid interfacial precipitation method (LLIP method). The length growth of C60NWs was investigated for various volume ratios between C60-saturated toluene solution and isopropyl alcohol. The length growth of C60NWs varied depending on the volume ratio. The optimum volume ratio in preparing C60NWs with a high uniformity was found to be 1:1. The water contained in isopropyl alcohol markedly influence the length growth of C60NWs. C60NWs did not form when isopropyl alcohol containing more than 2.5 mass % water was used.

Synthesis and Properties of Fullerene Nanowhiskers and Fullerene Nanotubes

Fine needle-like crystals of C60, "C60 nanowhiskers", were discovered in 2001 in a colloidal solution of PZT ceramics added with C60. Not only the C60 nanowhiskers but also the nanowhiskers composed of C70 and C60 derivatives can be synthesized at room temperature by using the liquid-liquid interfacial precipitation method (LLIP method). Tubular fullerene nanowhiskers, "fullerene nanotubes" composed of C60 and C70 molecules can be synthesized by the LLIP method as well. These fullerene nanofibers are pure carbon semiconductors and have wide potential applications in the fields of electronics, optics, MEMS, catalysts, energy and environment. The fullerene nanofibers are now establishing a new scientific field of nanomaterials for the coming all carbon device age. In this paper, the synthesis and various novel properties of fullerene nanofibers are presented.

A geometric constraint, the head-to-tail exclusion rule, may be the basis for the isolated-pentagon rule in fullerenes with more than 60 vertices

Carbon atoms self-assemble into the famous soccer-ball shaped Buckminsterfullerene (C(60)), the smallest fullerene cage that obeys the isolated-pentagon rule (IPR). Carbon atoms self-assemble into larger (n > 60 vertices) empty cages as well-but only the few that obey the IPR-and at least 1 small fullerene (n <or= 60) with adjacent pentagons. Clathrin protein also self-assembles into small fullerene cages with adjacent pentagons, but just a few of those. We asked why carbon atoms and clathrin proteins self-assembled into just those IPR and small cage isomers. In answer, we described a geometric constraint-the head-to-tail exclusion rule-that permits self-assembly of just the following fullerene cages: among the 5,769 possible small cages (n <or= 60 vertices) with adjacent pentagons, only 15; the soccer ball (n = 60); and among the 216,739 large cages with 60 < n <or= 84 vertices, only the 50 IPR ones. The last finding was a complete surprise. Here, by showing that the largest permitted fullerene with adjacent pentagons is one with 60 vertices and a ring of interleaved hexagons and pentagon pairs, we prove that for all n > 60, the head-to-tail exclusion rule permits only (and all) fullerene cages and nanotubes that obey the IPR. We therefore suggest that self-assembly that obeys the IPR may be explained by the head-to-tail exclusion rule, a geometric constraint.

Cycloaddition and Complexation of Transition Metal Oxides with Materials Featuring an Analogous Bonding Motif: Alkenes, Diamond (100), Fullerene and Carbon Nanotubes

Cycloaddition and Complexation of Transition Metal Oxides with Materials Featuring an Analogous Bonding Motif: Alkenes, Diamond (100), Fullerene and Carbon Nanotubes

HIGH YIELD PREPARATION OF FULLERENE NANOWHISKERS AND NANOTUBES BY THE SOLUTION ROUTE

The effect of ultraviolet, visible and near-infrared irradiation on the yield and morphology of single crystalline C 60 fullerene nanowhiskers (FNWs) and nanotubes (FNTs) was investigated in an effort to produce large-scale quantities of FNWs and FNTs. These fullerene nanomaterials were synthesized by the liquid–liquid interfacial precipitation method using pyridine and isopropyl alcohol (IPA) as solvents. The C 60–pyridine solution was illuminated using different wavelengths for 24 h at ambient pressure and temperature before addition of IPA. High yields (30–38 mg/L) were obtained upon irradiation using wavelengths in the ultraviolet region in accordance with the increased photoabsorption signal of solid C 60 and C 60 dissolved in pyridine acquired by a UV-VIS-NIR spectrophotometer. However, elevated yields (21–27 mg/L) were also obtained in the 600–800 nm regions, where C 60 absorption is particularly weak. Such an enhanced yield of FNTs and FNWs is probably related to the reported rise in transient absorption of the triplet excited state of C 60 in the 740 nm region formed by the decay of the photoexcited singlet C 60 through intersystem crossing. The formation of photopolymerized fullerene nanofibers was also observed by Raman spectroscopy, it is attributed to ultraviolet and visible light irradiation. SEM and TEM observations suggest that preparation of FNWs and FNTs by irradiation using different wavelengths of light does not produce apparent morphological transformations on the surface of these fullerene materials.

GROWTH RATE MEASUREMENT OF C60 FULLERENE NANOWHISKERS

The growth rate of C 60 fullerene nanowhiskers ( C 60NWs) prepared by the liquid–liquid interfacial precipitation method is measured and the growth mechanism is discussed. The growth of C 60NWs is investigated from the data obtained at the growth temperatures of 5, 10, 15 and 20°C. It is found that the convection of the solution scarcely influences the growth rate, suggesting that a surface reaction of C 60 molecules dominates the growth process. The activation energy of C 60NWs' growth is estimated at about 52.8 kJ/mol from their initial stage of growth. This activation energy is much greater than that of C 60 diffusion in solutions found in the literature. This result suggests that the desolvation process of C 60 on the whisker surface governs the growth of C 60NWs.

Fe-DECORATED FULLERENE (C60) NANOWHISKERS FOR ENVIRONMENTAL APPLICATION

Fe -decorated fullerene nanowhiskers were prepared by using the liquid–liquid interfacial precipitation method. The prepared nanowhiskers were characterized using scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), X-ray diffraction (XRD) and Raman spectroscopy. Formation of both tubular and nontubular nanowhiskers was observed with fine dispersion of Fe ions. The XRD and Raman-spectroscopic studies showed the fcc crystalline nature and polymerization of the nanowhiskers, respectively. The results were compared with Ce - and Ni -incorporated fullerene nanowhiskers.

Adsorption and hysteresis of bisphenol A and 17alpha-ethinyl estradiol on carbon nanomaterials.

Adsorption of 17alpha-ethinyl estradiol (EE2) and bisphenol A (BPA) on carbon nanomaterials (CNMs) was investigated. Single point adsorption coefficients (K) showed significant relationship with specific surface areas of CNMs for both chemicals, indicating surface area is a major factor for EDC adsorption on CNMs. BPA adsorption capacity is higher than EE2 on fullerene and single-walled carbon nanotubes (SWCNT). Our molecular conformation simulation indicated that BPA has a unique ability to adsorb on the curvature surface of CNMs because of its "butterfly" structure of two benzene rings. The higher adsorption capacity of BPA over EE2 is well explained by considering helical (diagonal) coverage of BPA on the CNMs surface and wedging of BPA into the groove and interstitial region of CNM bundles or aggregates. The comparison of K(HW) (hexadecane-water partition coefficient) normalized adsorption coefficients between EDCs and several polyaromatic hydrocarbons indicates that pi-pi electron donor--acceptor system is an important mechanism forthe adsorption of benzene-containing chemicals on CNMs. The high adsorption capacity and strong desorption hysteresis of both chemicals on SWCNT indicate that SWCNT is a potential adsorbent for water treatment.

Synthesis and photophysics of novel 8-hydroxyquinoline aluminum metal dye with hole transfer groups

A novel luminescent dye metal complex, (CZHQ) 3Al, with 8-hydroxyquinoline aluminum and hole-transporting carbazole units was designed and synthesized. The (CZHQ) 3Al optical properties were carefully investigated by UV–vis absorption and fluorescence spectra in diluent solution. The results showed that the luminescent quantum yield of (CZHQ) 3Al was 0.62 in DMSO and it emitted red-light with the band gap of 2.89 eV estimated from the onset absorption. In addition, the light-emission of (CZHQ) 3Al can be quenched by electron acceptor (dimethylterephalate), where the process followed the Stern–Volmer equation. However, the fluorescent intensities of (CZHQ) 3Al were slowly increased with the addition of electron donor ( N, N-dimethylaniline). Furthermore, the molecular interactions of (CZHQ) 3Al with fullerene (C 60) and carbon nanotubes (CNTs) were also respectively investigated, which indicated the metal dye can be used as new fluorescent probe.

Synthesis and photophysics of novel 8-hydroxyquinoline aluminum metal complex with 1,3,4-oxadiazole units

A novel luminescent metal complex, (OXHQ) 3Al, with 8-hydroxyquinoline aluminum and electron-transporting 1,3,4-oxadiazole unit was designed and synthesized. The photophysical processes were investigated by UV–vis absorption and fluorescence emission spectra in diluent solution. The results showed that the luminescence quantum yield of (OXHQ) 3Al was 0.67 in DMSO and it emitted blue light with the band gap of 3.13 eV estimated from the onset absorption. In addition, the light-emitting of (OXHQ) 3Al can be quenched by electron acceptor (dimethylterephalate), where the processes followed the Stern–Volmer equation. However, with the addition of electron donor ( N, N-dimethylaniline) fluorescent intensity of (OXHQ) 3Al was increased and emission peak was lightly blue-shift. Furthermore, the molecular interactions of (OXHQ) 3Al with fullerene (C 60) or carbon nanotubes (CNTs) were also carefully investigated.

Self-assembled tetrapyrrole–fullerene and tetrapyrrole–carbon nanotube donor–acceptor hybrids for light induced electron transfer applications

This review article highlights the recent progress made in the design and study of self-assembled supramolecular architectures based on tetrapyrrole macrocycles as donors, and fullerene and carbon nanotubes as electron acceptors for electron and energy transfer applications in solution. The remarkable features of the utilized biomimetic organization principles viz., hydrogen bonding, π–π stacking, metal-mediated complexation, and electrostatic attraction in governing the stability and geometry of the nanohybrids, and their significance in controlling the structure and electron transfer properties are discussed.

AN INDEX THEOREM FOR GRAPHENE

We consider a graphene sheet folded in an arbitrary geometry, compact or with nanotube-like open boundaries. In the continuous limit, the Hamiltonian takes the form of the Dirac operator, which provides a good description of the low energy spectrum of the lattice system. We derive an index theorem that relates the zero energy modes of the graphene sheet with the topology of the lattice. The result coincides with analytical and numerical studies for the known cases of fullerene molecules and carbon nanotubes, and it extends to more complicated molecules. Potential applications to topological quantum computation are discussed.

Preparation and characterization of Ni incorporated fullerene nanowhiskers

Ni incorporated Fullerene (C 60) nanowhiskers have been prepared by liquid–liquid interfacial precipitation method. The prepared nanowhiskers were characterized using various analytical tools such as optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and micro-Raman spectroscopy. The microscopic images reveal that the formation of tubular and non tubular nanowhiskers with fine dispersion of Ni atoms in the nanowhiskers. The TEM mapping analysis confirms the presence of Ni atoms in the nanowhiskers. XRD analysis and the electron diffraction pattern substantiate the presence of fcc crystalline structure and Raman spectroscopy reveals the polymerization of nanowhiskers.

Carbon nanostructures in an ammonium medium

The reaction of fullerene C60, single- and multi-walled carbon nanotubes (SWNTs and MWNTs, respectively), as well as a mixture of these carbon nanomaterials with 8–10 wt% of ammonium chloride (reaction promoter) with ammonia as a source of hydrogen and nitrogen, at an initial ammonium pressure of 0.6–0.8 MPa in the temperature range 20–550°C was studied. The reaction at 450°C is accompanied by hydrogenation and nitrogenation of the fullerite matrix, and at 500°C decomposition of the fullerene carcass occurs. Physicochemical properties of the hydride-nitride phases formed by the reaction were studied. Single- and multiwalled nanotubes were shown to be stable in an ammonium medium at 20–450°C, while at 500°C their ends are opened.