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Fullerene

About: Fullerene is a research topic. Over the lifetime, 12723 publications have been published within this topic receiving 359173 citations.


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Journal ArticleDOI
01 Jan 1992-Nature
TL;DR: In this paper, the electron paramagnetic resonance spectrum of a mixture of metal-containing fullerenes was measured, both in solution and in the solid state, which revealed that the lanthanum atom has a formal charge of 3+, and the C82a charge was 3−.
Abstract: THE conjecture that atoms can be trapped inside closed carbon cages such as the fullerenes was first made by Kroto et al1. Mass spectroscopic evidence obtained soon after2 suggested that lanthanum atoms were encapsulated in fullerenes prepared by laser vaporization of a lanthanum-impregnated graphite disk, and these results were later corroborated3,4. Recently, helium atoms have been incorporated into fullerenes through collisions in the gas phase5, and evidence has been obtained for the formation of metal-containing fullerenes during arc burning of composite graphite rods6. All of these studies, however, have produced quantities too small for characterization using standard spectroscopic techniques. We report here the preparation of milligram quantities of lanthanum-containing C82, which can be solvent-extracted in yields of about 2% along with empty C60 and C70 cages. We have measured the electron paramagnetic resonance spectrum of this mixture, both in solution and in the solid state, which reveals that the lanthanum atom has a formal charge of 3+, and the C82a charge of 3-. This runs contrary to some expectations that the doubly charged f ulleride anions would be the most stable species6,7; it also reveals that the fullerene cages have the same formal charge as in the superconducting alkali-metal-doped phases8,9.

370 citations

Journal ArticleDOI
TL;DR: First-principles density functional theory studies show that both Ca and Sr can bind strongly to the C60 surface, and highly prefer monolayer coating, thereby explaining existing experimental observations.
Abstract: We explore theoretically the feasibility of functionalizing carbon nanostructures for hydrogen storage, focusing on the coating of C60 fullerenes with light alkaline-earth metals. Our first-principles density functional theory studies show that both Ca and Sr can bind strongly to the C60 surface, and highly prefer monolayer coating, thereby explaining existing experimental observations. The strong binding is attributed to an intriguing charge transfer mechanism involving the empty d levels of the metal elements. The charge redistribution, in turn, gives rise to electric fields surrounding the coated fullerenes, which can now function as ideal molecular hydrogen attractors. With a hydrogen uptake of >8.4 wt % on Ca32C60, Ca is superior to all the recently suggested metal coating elements.

368 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that the structure of amorphous carbon (ta-C) can be simulated using ab initio quantum mechanics with high elasticity and low friction coefficients.
Abstract: Electron configurations close to the tetrahedral hybridization are found in pure amorphous carbon at a concentration which depends on preparation conditions. Tetrahedral bonding at levels of approximately 80% is found in amorphous carbons formed from beams of carbon ions with energies in a `window' between 20 eV and approximately 500 eV. Suitable techniques for its formation include cathodic arc deposition, ion beam deposition and laser ablation. Similar material appears to be formed by pressure treatment of fullerene precursors and by displacement damage in diamond. Highly tetrahedral forms of amorphous carbon (ta-C) show electronic, optical and mechanical properties which approach those of diamond and are quite different from amorphous carbons with low content. Useful techniques for determining the content include electron energy loss spectroscopy, electron and neutron diffraction and Raman spectroscopy. Considerable progress has been made in the understanding of this material by simulating its structure in the computer with a range of techniques from empirical potentials to ab initio quantum mechanics. The structure shows departures from an idealized glassy state of diamond which would have a random tetrahedral network structure as used to describe amorphous silicon and germanium. A surprising feature of the structure simulated using ab initio methods is the presence of small rings containing three or four carbon atoms. The electronic and optical properties are strongly influenced by the residual of carbon. Applications to electronic devices are at an early stage with the demonstration of photoconductivity and some simple junction devices. Applications as a wear resistant coating are promising, since the theoretically predicted high values of elastic constants, comparable to but less than those of diamond, are achieved experimentally, together with low friction coefficients.

367 citations

Journal ArticleDOI
09 Mar 2001-Science
TL;DR: A laser light scattering study of the association behavior of the potassium salt of pentaphenyl fullerene in water revealed that the hydrocarbon anions Ph5C60- associate into bilayers, forming stable spherical vesicles with an average hydrodynamic radius and a radius of gyration of about 17 nanometers at a very low critical aggregation concentration.
Abstract: The low solubility of fullerenes in aqueous solution limits their applications in biology. By appropriate substitution, the fullerenes can be transformed into stabilized anions that are water soluble and can form large aggregated structures. A laser light scattering study of the association behavior of the potassium salt of pentaphenyl fullerene (Ph5C60K) in water revealed that the hydrocarbon anions Ph5C60- associate into bilayers, forming stable spherical vesicles with an average hydrodynamic radius and a radius of gyration of about 17 nanometers at a very low critical aggregation concentration of less than 10(-7) moles per liter. The average aggregation number of associated particles in these large spherical vesicles is about 1.2 x 10(4).

362 citations

Journal ArticleDOI
TL;DR: In this article, a novel strategy using fullerenes for the construction of solar energy conversion systems that mimic the primary electron transfer events in photosynthesis was proposed, which can accelerate photoinduced charge separation and slow down charge recombination, properties that are in sharp contrast with those of conventional two-dimensional aromatic acceptors such as quinones and imides.

362 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023542
20221,244
2021366
2020346
2019411
2018420