Fullerene

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

Carbon fibers based on C60 and their symmetry.

Abstract: Carbon fibers based on the recently discovered fullerenes are proposed and their symmetry properties examined with respect to Raman- and infrared-active vibrational modes. Such carbon fibers are of interest as approximating the smallest possible diameter for a vapor-grown carbon fiber, and can be used for model calculations for the structure and properties of this limiting case of a carbon fiber.

Mechanism of strain release in carbon nanotubes

Abstract: Static and dynamical properties of carbon nanotubes under uniaxial tension have been investigated via quantum and classical simulations. In strained nanotubes at high temperatures we observe the spontaneous formation of double pentagon-heptagon defect pairs. Tubes containing these defects are energetically preferred to uniformly stretched tubes at strains greater than 5%. These topological defects act as nucleation centers for the formation of dislocations in the originally ideal graphite network, and they constitute the onset of a plastic deformation of the carbon nanotube. The mechanism of formation of such defects, their energetics, and transformations are described. @S0163-1829~98!50208-1# Since their discovery in 1991, 1 carbon nanotubes have attracted much interest due to their peculiar character at a crossroad between traditional carbon fibers and fullerenes. They hold substantial promise for use as superstrong fibers, catalysts, and as components of novel electronic devices. Despite the potential impact that new composites based on carbon nanotubes would have in many areas of science and industry, very little is known about the microscopic origin of their strength and a complete theoretical understanding of their behavior is desirable. The excellent resistance of carbon nanotubes to bending has already been observed experimentally and studied theoretically. 2‐4 The remarkable flexibility of the hexagonal network allows the system to sustain very high bending angles, kinks, and highly strained regions. In addition, nanotubes are observed to be extremely resilient, suggesting that even largely distorted configurations ~axial compression, twisting! can be due to elastic deformations with no atomic defects involved. 2,3,5,6

Bimolecular Crystals of Fullerenes in Conjugated Polymers and the Implications of Molecular Mixing for Solar Cells

Abstract: The performance of polymer:fullerene bulk heterojunction solar cells is heavily influenced by the interpenetrating nanostructure formed by the two semiconductors because the size of the phases, the nature of the interface, and molecular packing affect exciton dissociation, recombination, and charge transport. Here, X-ray diffraction is used to demonstrate the formation of stable, well-ordered bimolecular crystals of fullerene intercalated between the side-chains of the semiconducting polymer poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene. It is shown that fullerene intercalation is general and is likely to occur in blends with both amorphous and semicrystalline polymers when there is enough free volume between the side-chains to accommodate the fullerene molecule. These findings offer explanations for why luminescence is completely quenched in crystals much larger than exciton diffusion lengths, how the hole mobility of poly(2-methoxy-5-(3′,7′-dimethyloxy)-p-phylene vinylene) increases by over 2 orders of magnitude when blended with fullerene derivatives, and why large-scale phase separation occurs in some polymer:fullerene blend ratios while thermodynamically stable mixing on the molecular scale occurs for others. Furthermore, it is shown that intercalation of fullerenes between side chains mostly determines the optimum polymer:fullerene blending ratios. These discoveries suggest a method of intentionally designing bimolecular crystals and tuning their properties to create novel materials for photovoltaic and other applications.

Noble Gas Atoms Inside Fullerenes

Abstract: Heating fullerenes at 650°C under 3000 atmospheres of the noble gases helium, neon, argon, krypton, and xenon introduces these atoms into the fullerene cages in about one in 1000 molecules. A “window” mechanism in which one or more of the carbon-carbon bonds of the cage is broken has been proposed to explain the process. The amount of gas inside the fullerenes can be measured by heating to 1000°C to expel the gases, which can then be measured by mass spectroscopy. Information obtained from the nuclear magnetic resonance spectra of helium-3-labeled fullerenes indicates that the magnetic field inside the cage is altered by aromatic ring current effects. Each higher fullerene isomer and each chemical derivative of a fullerene that has been studied so far has given a distinct helium nuclear magnetic resonance peak.