Showing papers on "Fullerene published in 2012"
Book•
01 Apr 2012TL;DR: The first two-dimensional carbon material, Graphene, was only obtained very recently, immediately attracting a great deal of attention as discussed by the authors, and it has been observed that electrons behave like massless relativistic particles.
Abstract: Carbon is one of the most intriguing elements in the Periodic Table. It forms many allotropes, some known from ancient times (diamond and graphite) and some discovered 10-20 years ago (fullerenes and nanotubes). Interestingly, the two-dimensional form (graphene) was only obtained very recently, immediately attracting a great deal of attention. Electrons in graphene, obeying a linear dispersion relation, behave like massless relativistic particles. This results in the observation of a number of very peculiar electronic properties – from an anomalous quantum Hall effect to the absence of localization – in this, the first two-dimensional material. It also provides a bridge between condensed matter physics and quantum electrodynamics, and opens new perspectives for carbon-based electronics.
1,075 citations
TL;DR: In this article, the formation of a relatively pure, molecularly ordered phase of the fullerene component, phenyl-C61-butyric acid methyl ester (PCBM), may be the key factor driving the spatial separation of photogenerated electrons and holes in many organic solar cells.
Abstract: Solution processed polymer/fullerene blend films are receiving extensive attention as the photoactive layer of organic solar cells. In this paper we report a range of photophysical, electrochemical, physicochemical and structural data which provide evidence that formation of a relatively pure, molecularly ordered phase of the fullerene component, phenyl-C61-butyric acid methyl ester (PCBM), may be the key factor driving the spatial separation of photogenerated electrons and holes in many of these devices. PCBM crystallisation is shown to result in an increase in its electron affinity, providing an energetic driving force for spatial separation of electrons and holes. Based upon our observations, we propose a functional model applicable to many organic bulk heterojunction devices based upon charge generation in a finely intermixed polymer/fullerene phase followed by spatial separation of electrons and holes at the interface of this mixed phase with crystalline PCBM domains. This model has significant implications for the design of alternative acceptor materials to PCBM for organic solar cells.
421 citations
TL;DR: The kinetic data obtained in solution are found to be quite useful to predict the efficiencies of photovoltaic cells constructed on semiconductor nanoparticle modified electrodes and their photocatalytic processes.
Abstract: Photosensitized electron-transfer processes of nanocarbon materials hybridized with electron donating or electron accepting molecules have been surveyed in this tutorial review on the basis of the recent results reported mainly from our laboratories. As nano-carbon materials, fullerenes and single wall carbon nanotubes (SWCNTs) have been employed. Fullerenes act as photo-sensitizing electron acceptors with respect to a wide variety of electron donors; in addition, the fullerenes act as good ground state electron acceptors in the presence of light-absorbing electron donors such as porphyrins and phthalocyanines. In the case of SWCNTs, their ground states act as electron acceptor and electron donors, depending on the photosensitizers. For example, with respect to the photoexcited porphyrins and phthalocyanines, SWCNTs usually act as electron acceptors, whereas for the photoexcited fullerenes, SWCNTs act as electron donors. The diameter sorted semi-conductive SWCNTs have been used to verify the size-dependent electron transfer rates. For the confirmation of the electron transfer processes, the transient absorption methods have been widely used, in addition to the time-resolved fluorescence spectral measurements. The kinetic data thus obtained in solution are found to be quite useful to predict the efficiencies of photovoltaic cells constructed on semiconductor nanoparticle modified electrodes and their photocatalytic processes.
340 citations
TL;DR: The volume fraction of polymer-rich, fullerene- rich, and polymer-fullerene mixed domains can be tuned using the miscibility leading to improvement in the charge collection efficiency and PCE in P3HS:fullerenes BHJ solar cells.
Abstract: The improvement of the power conversion efficiency (PCE) of polymer bulk heterojunction (BHJ) solar cells has generally been achieved through synthetic design to control frontier molecular orbital energies and molecular ordering of the electron-donating polymer. An alternate approach to control the PCE of a BHJ is to tune the miscibility of the fullerene and a semiconducting polymer by varying the structure of the fullerene. The miscibility of a series of 1,4-fullerene adducts in the semiconducting polymer, poly(3-hexylselenophene), P3HS, was measured by dynamic secondary ion mass spectrometry using a model bilayer structure. The microstructure of the bilayer was investigated using high-angle annular dark-field scanning transmission microscopy and linked to the polymer-fullerene miscibility. Finally, P3HS:fullerene BHJ solar cells were fabricated from each fullerene derivative, enabling the correlation of the active layer microstructure to the charge collection efficiency and resulting PCE of each system....
196 citations
TL;DR: High-resolution FT-ICR mass spectrometry is used to investigate formation of the smallest fullerene by use of a pulsed laser vaporization cluster source and shows that M@C(28) is formed by a bottom-up growth mechanism and is a precursor to larger metallofullerenes.
Abstract: The smallest fullerene to form in condensing carbon vapor has received considerable interest since the discovery of Buckminsterfullerene, C60. Smaller fullerenes remain a largely unexplored class of all-carbon molecules that are predicted to exhibit fascinating properties due to the large degree of curvature and resulting highly pyramidalized carbon atoms in their structures. However, that curvature also renders the smallest fullerenes highly reactive, making them difficult to detect experimentally. Gas-phase attempts to investigate the smallest fullerene by stabilization through cage encapsulation of a metal have been hindered by the complexity of mass spectra that result from vaporization experiments which include non-fullerene clusters, empty cages, and metallofullerenes. We use high-resolution FT-ICR mass spectrometry to overcome that problem and investigate formation of the smallest fullerene by use of a pulsed laser vaporization cluster source. Here, we report that the C28 fullerene stabilized by en...
165 citations
TL;DR: Carbon is anything but a new material, yet ubiquitously applicable for many catalytic transformations in modern organic chemistry, as demonstrated by many recent publications within the revitalized field of carbocatalysis.
Abstract: Carbon is anything but a new material, yet ubiquitously applicable for many catalytic transformations in modern organic chemistry. It is highly versatile, as it occurs as modifications abundantly available as 1–3D carbonaceous materials due to technical progress. In addition, materials such as activated charcoal, ordered mesoporous carbon (OMC), graphite and graphene (oxide), carbon nanotubes (CNTs), nanospheres (nano-onions, fullerenes), and many others are no “innocent” supports, as demonstrated by many recent publications within the revitalized field of “carbocatalysis”. By nature, carbon scaffolds offer a perfect link between nanoscaled matter and organic molecules, which makes them an ideal cornerstone for molecular catalysts. Apart from this inherent chemical significance, the physical properties (e.g., different conductivity) are equally important for the performance of heterogeneous or immobilized homogeneous catalysts. Careful selection of the carbon scaffold enables control of reactivity by tuni...
164 citations
TL;DR: The results show that the previously proposed M, bct-C(4), W and Z allotropes belong to the currently proposed families and that depending on the topological arrangement of the native carbon rings numerous other members are found that can help to understand the structural phase transformation of cold-compressed graphite and carbon nanotubes (CNTs).
Abstract: We report a general scheme to systematically construct two classes of structural families of superhard sp(3) carbon allotropes of cold-compressed graphite through the topological analysis of odd 5 + 7 or even 4 + 8 membered carbon rings stemmed from the stacking of zigzag and armchair chains. Our results show that the previously proposed M, bct-C-4, W and Z allotropes belong to our currently proposed families and that depending on the topological arrangement of the native carbon rings numerous other members are found that can help us understand the structural phase transformation of cold-compressed graphite and carbon nanotubes (CNTs). In particular, we predict the existence of two simple allotropes, R and P carbon, which match well the experimental x-ray diffraction patterns of cold-compressed graphite and CNTs, respectively, display a transparent wide-gap insulator ground state and possess a large Vickers hardness comparable to diamond.
158 citations
TL;DR: Using x-ray diffraction, Raman spectroscopy, and quantum molecular dynamics simulation, it is observed that, although carbon-60 cages were crushed and became amorphous, the solvent molecules remained intact, playing a crucial role in maintaining the long-range periodicity.
Abstract: Solid-state materials can be categorized by their structures into crystalline (having periodic translation symmetry), amorphous (no periodic and orientational symmetry), and quasi-crystalline (having orientational but not periodic translation symmetry) phases. Hybridization of crystalline and amorphous structures at the atomic level has not been experimentally observed. We report the discovery of a long-range ordered material constructed from units of amorphous carbon clusters that was synthesized by compressing solvated fullerenes. Using x-ray diffraction, Raman spectroscopy, and quantum molecular dynamics simulation, we observed that, although carbon-60 cages were crushed and became amorphous, the solvent molecules remained intact, playing a crucial role in maintaining the long-range periodicity. Once formed, the high-pressure phase is quenchable back to ambient conditions and is ultra-incompressible, with the ability to indent diamond.
157 citations
TL;DR: The results shed new light on the fundamental processes that govern self-assembly of carbon networks, and the processes that are revealed are likely be involved in the formation of other carbon nanostructures from carbon vapour, such as nanotubes and graphene.
Abstract: The formation mechanisms of fullerenes remain unclear. This study shows that fullerenes self-assemble through a closed network growth mechanism in which atomic carbon and C2 are incorporated into the growing closed cages.
155 citations
Journal Article•
TL;DR: This work uses the minima hopping global geometry optimization method on the density functional potential energy surface to show that the energy landscape of boron clusters is glasslike, and presents a methodology which can make predictions on the feasibility of the synthesis of new nanostructures.
Abstract: Using the minima hopping global geometry optimization method on the density functional potential energy surface we show that the energy landscape of boron clusters is glasslike. Larger boron clusters have many structures which are lower in energy than the cages. This is in contrast to carbon and boron nitride systems which can be clearly identified as structure seekers. The differences in the potential energy landscape explain why carbon and boron nitride systems are found in nature whereas pure boron fullerenes have not been found. We thus present a methodology which can make predictions on the feasibility of the synthesis of new nanostructures.
147 citations
TL;DR: In this article, the particle swarm optimization algorithm combined with first-principles methods was used to search for two-dimensional metastable boron sheets by using the first principles methods.
Abstract: We searched for two-dimensional metastable boron sheets by using the particle swarm optimization algorithm combined with first-principles methods. We present several possible boron sheets composed of triangular and hexagonal motifs. The calculated total energy shows that these boron sheets are less stable than α-sheet and two recently predicted 1/8 and 2/15 B-layers. The energy difference between the new proposed struc-1/8 boron sheet and the known α-sheet, 1/8 and 2/15 B-layers, is less than 0.01 eV/atom. The calculated total density states of these boron sheets show that they are metallic. The multicenter chemical bonds of the relatively stable boron sheets are analyzed using the electron localization function. Because two-dimensional sheets are the building blocks of corresponding nanotubes and fullerenes, the proposed metastable boron sheets, not only with the most stable boron sheets, are expected to advance further investigations and understandings on boron nanotubes and fullerenes.
TL;DR: X-ray diffraction is used to determine how the fullerenes are arranged within crystals of poly-(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) and suggests that poor electron transport in the molecularly mixed domains may account for the reduced solar cell performance of blends with fullerene intercalation.
Abstract: We compare the solar cell performance of several polymers with the conventional electron acceptor phenyl-C61-butyric acid methyl ester (PCBM) to fullerenes with one to three indene adducts. We find that the multiadduct fullerenes with lower electron affinity improve the efficiency of the solar cells only when they do not intercalate between the polymer side chains. When they intercalate between the side chains, the multiadduct fullerenes substantially reduce solar cell photocurrent. We use X-ray diffraction to determine how the fullerenes are arranged within crystals of poly-(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) and suggest that poor electron transport in the molecularly mixed domains may account for the reduced solar cell performance of blends with fullerene intercalation.
TL;DR: Graphene has created tremendous interest to both physicists and chemists due to its various fascinating properties, both observed and predicted with possible potential applications in nanoelectronics, supercapacitors, solar cells, batteries, flexible displays, hydrogen storage, and sensors.
Abstract: Graphene, a one-atom thick planar sheet of sp2 bonded carbon atoms packed in a honeycomb lattice, is considered to be the mother of all graphitic materials like fullerenes, carbon nanotubes, and graphite. Graphene has created tremendous interest to both physicists and chemists due to its various fascinating properties, both observed and predicted with possible potential applications in nanoelectronics, supercapacitors, solar cells, batteries, flexible displays, hydrogen storage, and sensors. In this paper, a brief overview on various aspects of graphene such as synthesis, functionalization, self-assembly, and some of its amazing properties along with its various applications ranging from sensors to energy storage devices had been illustrated.
TL;DR: In this paper, an investigation of the photodegradation of polymer: fullerene blend fi lms exposed to ambient conditions for a variety of polymer and fullerenes derivative combinations is presented.
Abstract: Understanding the stability and degradation mechanisms of organic solar materials is critically important to achieving long device lifetimes. Here, an investigation of the photodegradation of polymer:fullerene blend fi lms exposed to ambient conditions for a variety of polymer and fullerene derivative combinations is presented. Despite the wide range in polymer stabilities to photodegradation, the rate of irreversible polymer photobleaching in blend fi lms is found to consistently and dramatically increase with decreasing electron affi nity of the fullerene derivative. Furthermore, blends containing fullerenes with the smallest electron affi nities photobleached at a faster rate than fi lms of the pure polymer. These observations can be explained by a mechanism where both the polymer and fullerene donate photogenerated electrons to diatomic oxygen to form the superoxide radical anion which degrades the polymer.
TL;DR: This work reports the first enantioselective synthesis of a chiral azabuckybowl, triazasumanene, and confirms that the doping of nitrogen induces a more curved and deeper bowl structure than in all-carbon buckybowls.
Abstract: Nitrogen-doped fullerenes and carbon nanotubes have been produced, but the synthesis of nitrogen-doped buckybowls, is an unsolved challenge. Tan et al. report an enantioselective synthesis of triazasumanene, and show that nitrogen doping leads to deeper bowl structures than in all-carbon buckybowls.
Book•
05 Nov 2012
TL;DR: In this article, Yildirim, O. Zhou, J.E. Fischer, and Nunez-Regueiro studied the electronic properties of Fullerenes.
Abstract: Preface by the Editor. Preface by Sir Harold Kroto. 1. Production of Fullerenes W. Kratschmer. 2. Intercalation Compounds of Fullerenes I: Synthesis, Characterization, and Solid State Properties T. Yildirim, O. Zhou, J.E. Fischer. 3. Intercalation Compounds of Fullerenes II: Structure and Superconductivity of Alkali Metal Fullerides T. Yildirim, O. Zhou, J.E. Fischer. 4. Experimental Studies of the Electronic Structure of Fullerenes M. Knupfer, T. Pichler, M.S. Golden, J. Fink. 5. Polymer and Dimer Phases in Doped Fullerenes K. Prassides. 6. Vibrational Properties of Fullerenes and Fullerides H. Kuzmany, J. Winter. 7. Intercalation Compounds of Fullerenes III: Other Fullerides and Intercalated Nanotubes T. Yildirim, O. Zhou, J.E. Fischer. 8. Structural and Electronic Properties of C60 and C60 Derivatives in the Solid Phases: Calculations Based on Density-Functional Theory W. Andreoni, P. Giannozzi. 9. Carbon Nanotubes M.S. Dresselhaus, G. Dresselhaus, P.C. Eklund, A.M. Rao. 10. Electronic Structure of Carbon and Boron-Carbon-Nitrogen Nanotubes S.G. Louie. 11. Pressure Studies on Fullerenes M. Nunez-Regueiro, L. Marques, J.-L. Hodeau. Index of Materials.
TL;DR: Photosensitized electron-transfer processes of fullerenes hybridized with electron donating or other electron accepting molecules have been surveyed in this review on the basis of the recent results reported mainly from laboratories.
Abstract: Photosensitized electron-transfer processes of fullerenes hybridized with electron donating or other electron accepting molecules have been surveyed in this review on the basis of the recent results reported mainly from our laboratories. Fullerenes act as photo-sensitizing electron acceptors with respect to a wide variety of electron donors; in addition, fullerenes in the ground state also act as good electron acceptors in the presence of light-absorbing electron donors such as porphyrins. With single-wall carbon nanotubes (SWCNTs), the photoexcited fullerenes act as electron acceptor. In the case of triple fullerene/porphyrin/SWCNT architectures, the photoexcited porphyrins act as electron donors toward the fullerene and SWCNT. These mechanisms are rationalized with the molecular orbital considerations performed for these huge supramolecules. For the confirmation of the electron transfer processes, transient absorption methods have been used, in addition to time-resolved fluorescence spectral measurements. The kinetic data obtained in solution are found to be quite useful to predict the efficiencies of photovoltaic cells.
TL;DR: In this paper, the authors report on solar cells with active layers made solely of carbon nanomaterials that present the same advantages of conjugated polymer-based solar cells, namely, solution processable, potentially flexible, and chemically tunable, but with increased photostability and the possibility to revert photodegradation.
Abstract: Carbon materials are excellent candidates for photovoltaic solar cells: they are Earth-abundant, possess high optical absorption, and maintain superior thermal and photostability. Here we report on solar cells with active layers made solely of carbon nanomaterials that present the same advantages of conjugated polymer-based solar cells, namely, solution processable, potentially flexible, and chemically tunable, but with increased photostability and the possibility to revert photodegradation. The device active layer composition is optimized using ab initio density functional theory calculations to predict type-II band alignment and Schottky barrier formation. The best device fabricated is composed of PC70BM fullerene, semiconducting single-walled carbon nanotubes, and reduced graphene oxide. This active-layer composition achieves a power conversion efficiency of 1.3%—a record for solar cells based on carbon as the active material—and we calculate efficiency limits of up to 13% for the devices fabricated in...
TL;DR: In this paper, a versatile structurally favorable periodic sp2-bonded carbon atomic planar sheet with C4v symmetry was studied by means of the first-principles calculations.
Abstract: We study a versatile structurally favorable periodic sp2-bonded carbon atomic planar sheet with C4v symmetry by means of the first-principles calculations. This carbon allotrope is composed of carbon octagons and squares with two bond lengths and is thus dubbed as octagraphene. It is a semimetal with the Fermi surface consisting of one hole and one electron pocket, whose low-energy physics can be well described by a tight-binding model of π-electrons. Its Young's modulus, breaking strength, and Poisson's ratio are obtained to be 306 N/m, 34.4 N/m, and 0.13, respectively, which are close to those of graphene. The novel sawtooth and armchair carbon nanotubes as well as unconventional fullerenes can also be constructed from octagraphene. It is found that the Ti-absorbed octagraphene can be allowed for hydrogen storage with capacity around 7.76 wt. %.
TL;DR: In this article, X-ray diffraction, differential scanning calorimetry (DSC), and molecular simulations are used to study mixing in a variety of polymer:molecule blends by systematically varying the polymer and small molecular properties.
Abstract: While recent reports have established significant miscibility in polymer:fullerene blends used in organic solar cells, little is actually known about why polymers and fullerenes mix and how their mixing can be controlled. Here, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and molecular simulations are used to study mixing in a variety of polymer:molecule blends by systematically varying the polymer and small-molecule properties. It is found that a variety of polymer:fullerene blends mix by forming bimolecular crystals provided there is sufficient space between the polymer side chains to accommodate a fullerene. Polymer:tetrafluoro-tetracyanoquinodimethane (F4-TCNQ) bimolecular crystals were also observed, although bimolecular crystals did not form in the other studied polymer:non-fullerene blends, including those with both conjugated and non-conjugated small molecules. DSC and molecular simulations demonstrate that strong polymer–fullerene interactions can exist, and the calculations point to van der Waals interactions as a significant driving force for molecular mixing.
TL;DR: In this article, the design concept, synthesis, and features of fullerene derivatives having high lowest unoccupied molecular orbital (LUMO) levels to achieve high open-circuit voltage in...
Abstract: This review article describes design concept, synthesis, and features of fullerene derivatives having high lowest unoccupied molecular orbital (LUMO) levels to achieve high open-circuit voltage in ...
TL;DR: In this paper, a periodic $sp^2$-bonded carbon atomic planar sheet called octagraphene was constructed and its Young's modulus, breaking strength and Poisson's ratio were obtained.
Abstract: We study a versatile structurally favorable periodic $sp^2$-bonded carbon atomic planar sheet with $C_{4v}$ symmetry by means of the first-principles calculations. This carbon allotrope is composed of carbon octagons and squares with two bond lengths and is thus dubbed as octagraphene. It is a semimetal with the Fermi surface consisting of one hole and one electron pocket, whose low-energy physics can be well described by a tight-binding model of $\pi$-electrons. Its Young's modulus, breaking strength and Poisson's ratio are obtained to be 306 $N/m$, 34.4 $N/m$ and 0.13, respectively, which are close to those of graphene. The novel sawtooth and armchair carbon nanotubes as well as unconventional fullerenes can also be constructed from octagraphene. It is found that the Ti-absorbed octagraphene can be allowed for hydrogen storage with capacity around 7.76 wt%.
TL;DR: The cooperative self-assembly of functionalized fullerenes and all conjugated block copolymers (BCPs) containing polythiophene derivatives in both segments to yield solar cells with well-defined nanostructures and enhanced morphological stability was reported in this article.
Abstract: We report the cooperative self-assembly of functionalized fullerenes and all conjugated block copolymers (BCPs) containing polythiophene derivatives in both segments to yield solar cells with well-defined nanostructures and enhanced morphological stability. Favorable hydrogen bonding interactions between the COOH-functionalized fullerene, bis-[6, 6]-phenyl C61-butyric acid (bis-PCBA), and the tetraethyleneglycol side chains of poly(3-hexylthiophene)-block-poly[3-(2,5,8,11-tetraoxadodecane)thiophene] (P3HT-b-P3TODT) allows for high loading of bis-PCBA (up to 40 wt % to the blend) within the P3TODT domains, while preserving the lamellar morphology. Characterization by grazing incidence small-angle X-ray scattering, electron microscopy, and atomic force microscopy indicates that the periods of the structures range between 24 and 29 nm depending on the bis-PCBA loading. The hydrogen bond interactions between bis-PCBA and P3TODT segments further suppress crystallization and macrophase separation of the fullere...
TL;DR: In this article, the origin of open-circuit voltage (VOC) was studied for polymer solar cells based on a blend of poly(3-hexylthiophene) (P3HT) and seven fullerene derivatives with different LUMO energy levels and side chains.
Abstract: The origin of open-circuit voltage (VOC) was studied for polymer solar cells based on a blend of poly(3-hexylthiophene) (P3HT) and seven fullerene derivatives with different LUMO energy levels and side chains. The temperature dependence of J–V characteristics was analyzed by an equivalent circuit model. As a result, VOC increased with the decrease in the saturation current density J0 of the device. Furthermore, J0 was dependent on the activation energy EA for J0, which is related to the HOMO–LUMO energy gap between P3HT and fullerene. Interestingly, the pre-exponential term J00 for J0 was larger for pristine fullerenes than for substituted fullerene derivatives, suggesting that the electronic coupling between molecules also has substantial impact on VOC. This is probably because the recombination is non-diffusion-lmilited reaction depending on electron transfer at the P3HT/fullerene interface. In summary, the origin of VOC is ascribed not only to the relative HOMO–LUMO energy gap but also to the electronic couplings between fullerene/fullerene and polymer/fullerene.
TL;DR: In this article, the authors showed that the hydrogenation reaction on carbon doped B 11 N 12 C cluster is both thermodynamically favored and kinetically feasible under ambient conditions.
TL;DR: Experiments revealed that small boron cluster anions and cations are (quasi-)planar, and chemical bonding analysis given by AdNDP reveals that the B(14) cage is an all-boron fullerene with 18 delocalized σ-electrons following the 2(n+1)(2) rule of spherical aromaticity.
Abstract: Experiments revealed that small boron cluster anions and cations are (quasi-)planar. For neutral boron cluster, (quasi-)planar motifs are also suggested to be global minimum by many theoretical studies, and a structural transformation from quasi-planar to double-ring tubular structures occurs at B20. However, a missing opportunity is found for neutral B14, which is a flat cage and more stable than the previous quasi-planar one by high level ab initio calculations. The B14 cage has a large HOMO-LUMO gap (2.69 eV), and NICS values reveal that it is even more aromatic than the known most aromatic quasi-planar B12 and double-ring B20, which indicates a close-shell electronic structure.Chemical bondinganalysis given by AdNDP reveals that the B14 cage is an all-boron fullerene with 18 delocalized σ-electrons following the 2(n+1)2 rule of spherical aromaticity. The geometry and bonding features of the B14 cage are unique denying conversional thinking.
TL;DR: In this paper, the Spitzer mid-infrared spectrum of three fullerene-rich planetary nebulae in the Milky Way and the Magellanic Clouds was analyzed.
Abstract: We compare and analyze the Spitzer mid-infrared spectrum of three fullerene-rich planetary nebulae in the Milky Way and the Magellanic Clouds: Tc1, SMP SMC 16, and SMP LMC 56. The three planetary nebulae share many spectroscopic similarities. The strongest circumstellar emission bands correspond to the infrared active vibrational modes of the fullerene species C60 and little or no emission is present from polycyclic aromatic hydrocarbons. The strengths of the fullerene bands in the three planetary nebulae are very similar, while the ratios of the [Ne III]15.5 μm/[Ne II]12.8 μm fine structure lines, an indicator of the strength of the radiation field, are markedly different. This raises questions about their excitation mechanism and we compare the fullerene emission to fluorescent and thermal models. In addition, the spectra show other interesting and common features, most notably in the 6-9 μm region, where a broad plateau with substructure dominates the emission. These features have previously been associated with mixtures of aromatic/aliphatic hydrocarbon solids. We hypothesize on the origin of this band, which is likely related to the fullerene formation mechanism, and compare it with modeled hydrogenated amorphous carbon that present emission in this region.
TL;DR: In this article, it was found that the carbon catalyst was retained and homogeneously dispersed within the polymer product, resulting in the formation of a carbon-filled composite, and the carbon transition from the lamellar morphology found in graphite oxide primarily to nanometre-sized, multiwalled fullerenes; no other discrete carbon morphologies were observed.
TL;DR: The single-bonded fullerene dimer RC60 C60R, which has a direct covalent bond between two C60 cages, is an interesting and unusual structure that is expected to display interesting optical and electronic properties through the interaction of two adjacent fullerenes.
Abstract: The single-bonded fullerene dimer RC60 C60R, which has a direct covalent bond between two C60 cages, is an interesting and unusual structure that is expected to display interesting optical and electronic properties through the interaction of two adjacent fullerene cages. Since the pioneering work by Krusic and co-workers, studies on ESR and X-ray crystalstructure analysis revealed that singly bonded fullerene dimers consist of racemic and meso isomers, which are in equilibrium with the monomer radical (RC60C) in solution. [3]
TL;DR: The applications of endohedral metallofullerenes in photovoltaic devices that feature greater efficiency than devices fabricated with empty fullererenes are referred to.
Abstract: In recent years, endohedral metallofullerenes have attracted tremendous interest not only in physics and chemistry, but also in interdisciplinary areas, such as materials and biological sciences. In this concept article we highlight recent results on different endohedral metallofullerenes based on lanthanides and their derivatives. The chemical and excited state reactivities of endohedral metallofullerenes are discussed for various endohedral clusters. Most important is the part that covers spectroscopic and kinetic assays of reductive and oxidative charge transfer evolving from photoexcited electron donors and electron acceptors, respectively, in a variety of electron donor-acceptor conjugates. Towards this end, we refer to the applications of endohedral metallofullerenes in photovoltaic devices that feature greater efficiency than devices fabricated with empty fullerenes. Herein, we focus mainly on results obtained in the groups of Akasaka, Echegoyen, and Guldi.