C60 Molecules Research Articles

Nano-pumping of fullerene and water molecules via a carbon nanotube in vacuum and aqueous environments

Nano-pumping of molecules via a carbon nanotube (CNT) can be achieved by mechanical actuation and wave propagation through the tube wall which is generated by two oscillating tips. By using non-equilibrium molecular dynamics (NEMD) simulations, we investigate the effects of tip frequency and amplitude in the pumping of a C20 molecule through (13, 0) CNT in the vacuum environment. The pumping action (C20 ejection) does not succeed in all tip frequencies and amplitudes, and there are optimum points in which successful pumping takes place. In one of these successful pumping conditions (specific tip frequency and amplitude), we have performed NEMD simulations of water and fullerene pumping in an aqueous environment and found that mechanical wave propagation is much weaker in such an environment and the pumping of C20 molecule does not succeed. Our simulations show that mechanical wave velocity along CNT can reach as a high as 5000 m/s. And during the pumping process, the C20 molecule accelerates due to transferring kinetic energy and the velocity remains constant since no external force is applied on C20 molecule.

New insights into DPP3Th and C70 based planar solar cells: A study combining DFT and experimental approach

In this work, small molecule-based solar cells were produced with a solution-processed diketopyrrolopyrrole-terthiophene (DPP3Th) as electron donor material and thermally evaporated fullerene (C70) film as acceptor material. The DPP3Th molecule was synthesized by the Suzuki cross-coupling reaction, resulting in energy values of the Highest Occupied Molecular Orbital (HOMO) equal to −5.30 eV, Lowest Unoccupied Molecular Orbital (LUMO) equal to −3.80 eV and optical band gap (Eg) of 1.60 eV. Theoretical simulation pointed out a limited torsional movement between the DPP and thiophene units, which contribute to shift the absorption edge of the DPP3Th to higher wavelengths and thus, resulting in extended photon collection. The DPP3Th and C70 molecules present complementary absorbance spectra (from 300 nm up to ca. 725 nm). Moreover, the DPP3Th/C70 interface provides a favorable energy barrier to electron transfer from the donor to the acceptor, resulting in open circuit voltage (Voc) of 0.72 V which is a promising step toward application in solar cells.

A sonochemical synthesis of the piperazine-containing adducts of the C60 fullerene

We have worked out a selective and efficient mode of the synthesis of substituted and unsubstituted piperazine-containing mono-adducts of the C60 fullerene. It is based on the C60 reaction with piperazine, 2-methylpiperazine, and 2-oxopiperazine under air, room temperature and ultrasonication. The intermediate of the sonochemical reaction is radical anion C60 •–, which was detected with EPR (g = 1.9968, ΔH = 5.9 G). This intermediate is generated due to one-electron transfer from piperazine to the C60 molecule.

Tuning the Intermolecular Electron Transfer of Low-Dimensional and Metal-Free BCN/C60 Electrocatalysts via Interfacial Defects for Efficient Hydrogen and Oxygen Electrochemistry.

The development of low-dimensional (LD) supramolecular materials with multifunctional electrocatalytic properties has sparked the attention of the catalysis community. Herein, we report the synthesis of a new class of 0D-2D heterostructures composed of boron carbon nitride nanosheets (BCN NSs) and fullerene molecules (C60/F) that exhibit multifunctional electrocatalytic properties for the hydrogen evolution/oxidation reactions (HER/HOR) and the oxygen evolution/reduction reactions (OER/ORR). The electrocatalytic properties were studied with varying F:BCN weight ratios to optimize the intermolecular electron transfer (ET) from the BCN NSs to the electron-accepting C60 molecules. The nanohybrid supramolecular material with 10 wt % F in BCN NSs (10% F/BCN) exhibited the largest Raman and C 1s binding energy shifts, which were associated with greater cooperativity interactions and enhanced ET processes at the F/BCN interface. This synergistic interfacial phenomenon resulted in highly active catalytic sites that markedly boosted electrocatalytic activity of the material. The 10% F/BCN showed the highest tetrafunctional catalytic performance, outperforming the OER catalytic activity of commercial RuO2 catalysts with a η10 of 390 mV and very competitive onset potential values of -0.042 and 0.92 V vs RHE for HER and ORR, respectively, and a current density value of 1.47 mA cm-2 at 0.1 V vs RHE with an ultralow ΔGH* value of -0.03 eV toward the HOR process. Additionally, the 10% F/BCN catalyst was also used as both cathode and anode in a water splitting device, delivering a cell potential of 1.61 V to reach a current density of 10 mA cm-2.

Delocalized exciton formation in C60 linear molecular aggregates.

Organic semiconducting materials containing C60 molecules are efficient acceptors for planar perovskite solar cells. In this work, we theoretically investigate the optical and excitonic properties of C60 linear molecular aggregates (composed of 1 to 7 C60 molecules) via the real-time-propagation rt-TDDFT technique. In the case of a single C60 molecule, the photoabsorption peaks are dominated by localized molecular excitons. We furthermore demonstrate that, in the case of linear molecular aggregates, the photoabsorption peaks are contributed by localized molecular excitons, charge transfer excitons, and Wannier-like delocalized excitons. This result is different to the accepted theory that only localized molecular excitons or charge transfer excitons can be produced in organic semiconducting materials. This work provides additional insights into the exciton formation in C60 molecular aggregates and may help in the rational design of efficient solar cells.

Молекулы фуллерена C-=SUB=-60-=/SUB=- под однослойным графеном на металлической подложке

The article discusses a hybrid nanomaterial - a monolayer of C60 molecules, which is located between a single-layer graphene and a metal substrate. Using the Lennard-Jones potential, formulas for the specific interaction energy of C60 fullerene molecules with single-layer graphene and a thick substrate are obtained. The specific energy of graphene adhesion and the equilibrium parameters of the considered nanostructure are calculated. The obtained theoretical results agree with the available experimental results.

Tailoring the magnetic ordering of the Cr4O5/Fe(001) surface via a controlled adsorption of C60 organic molecules.

We analyse the spinterface formed by a C60 molecular layer on a Fe(001) surface covered by a two-dimensional Cr4O5 layer. We consider different geometries, by combining the high symmetry adsorption sites of the surface with three possible orientations of the molecules in a fully relaxed Density Functional Theory calculation. We show that the local hybridization between the electronic states of the Cr4O5 layer and those of the organic molecules is able to modify the magnetic coupling of the Cr atoms. Both the intra-layer and the inter-layer magnetic interaction is indeed driven by O atoms of the two-dimensional oxide. We demonstrate that the C60 adsorption on the energetically most stable site turns the ferromagnetic intra-layer coupling into an antiferromagnetic one, and that antiferromagnetic to ferromagnetic switching and spin patterning of the substrate could be possible by adsorption on other sites.

Fifty years after the idea of C60 molecule

Fifty years after the idea of C60 molecule

Efficient approaches to solutions of partition function for condensed matters

The key problem of statistical physics standing over one hundred years is how to exactly calculate the partition function (or free energy), which severely hinders the theory to be applied to predict the thermodynamic properties of condensed matters. Very recently, we developed a direct integral approach (DIA) to the solutions and achieved ultrahigh computational efficiency and precision. In the present work, the background and the limitations of DIA were examined in details, and another method with the same efficiency was established to overcome the shortage of DIA for condensed system with lower density. The two methods were demonstrated with empirical potentials for solid and liquid cooper, solid argon and C60 molecules by comparing the derived internal energy or pressure with the results of vast molecular dynamics simulations, showing that the precision is about ten times higher than previous methods in a temperature range up to melting point. The ultrahigh efficiency enables the two methods to be performed with ab initio calculations and the experimental equation of state of solid copper up to ∼600 GPa was well reproduced, for the first time, from the partition function via density functional theory implemented.

Precise measurements of thermionic emission behaviors for hot gas-phase C60 and C70 molecules

Thermionic emission (delayed ionization) experiments have been performed on nanosecond laser excited gas-phase C60/C70 molecules. Time resolved velocity-map-imaging spectrometer is used to measure a series of photoion spectra in a wide range of time delay. The position distribution features of photoions recorded in each spectrum allow us to well identify a specific ionic species originating from pure delayed ionization process, namely from C60/C70 electron emission without contamination from other decay channels to be activated when molecules have an energy required for thermionic emission. Hence, thermionic emission behaviors for hot C60/C70 molecules can be obtained precisely, which may have significance for improving determination precisions of some basic decay parameters of neutral fullerene molecules.

Tunable Fulleretic Sodalite MOFs: Highly Efficient and Controllable Entrapment of C60 Fullerene via Mechanochemistry

Encapsulation and confinement of fullerene guests in metal-organic frameworks (MOFs) lead to a novel class of crystalline fulleretic materials with unique physicochemical properties and a broad field of potential applications. The control over the amount of target guests confined in the MOF structure remains a significant challenge, which is particularly pronounced in the confinement of hardly accessible fullerene derivatives. The main strategies used in constructing fulleretic composites are limited by the solubility of components used and solvent versus guest competition for inhabitation of the framework voids. As mechanochemical procedures often overcome these issues, we developed here solvent-free processing by ball milling to gain control over the encapsulation of bulky and rigid C60-fullerene into a sodalite MOF with large cages and narrow cage-apertures. A rapid, green, efficient, and stoichiometry-controlled mechanochemical processing afforded four model C60@zeolitic-imidazolate framework 8 (ZIF-8) crystalline materials containing target 15, 30, 60, and 100 mol % of fullerene entrapped in the accessible cages of the model sodalite zeolitic-imidazolate framework 8 (ZIF-8), in stark contrast to the solution-based strategies that resulted in almost no loading. Varying the fullerene content affects the framework’s vibrational properties, color and luminescence of the composites, and the electron-dose radiation stability. The computational and spectroscopic studies show that the fullerene is accommodated in the cage’s center and that the cage-to-cage transport is a hardly feasible and energetically unfavored process. However, the fast release of C60 molecules from ZIF-8 can be effectively controlled by the pH. The entrapment of fullerene molecules in ZIF-8 resulted in their effective isolation even in higher loadings, paving the way to other tunable porous fulleretics containing single-molecule magnets or nanoprobes available on low scales.

Construction of three-dimensional all-carbon C60/graphene hybrids and their use in high performance supercapacitors

Control of the three-dimensional (3D) pore structure of all-carbon C60/graphene hybrids was conducted by introducing C60 molecules into graphene laminates by a simple hydrothermal method to improve their performance as electrodes in supercapacitors. Results indicate that the strong π-π interaction between carbon hexagons in C60 and graphene skeletons favors the self-assembly of the 3D pore structure of the C60/graphene hybrids under hydrothermal conditions. The addition of C60 molecules gives the hybrids a hierarchical pore structure and redox-active sites, which contribute remarkably to the improved electrochemical performance. A specific capacitance of 332.3 F·g-1 at a current density of 1 A·g-1 was obtained in a 6 mol·L-1 potassium hydroxide solution for a hybrid optimized by an orthogonal experimental design method, which is 54.5% higher than that of the graphene without C60. This finding indicates that the all-carbon hybrids may be used as more competitive and promising electrodes for the fabrication of high performance supercapacitors.

Simulation of the processes of carbon atom and nanographene interaction with a molecule of fullerene C60

The results of numerical simulation of the processes of adsorption of a fullerene molecule by the nanographene edge is presented. It has been found that, as a result of adsorption, the spherical symmetry of the C60 fullerene molecule is broken and this symmetry violation depends on a method of adsorption on the graphene surface. The results of numerical simulation of scattering of carbon atoms and dimers by a C60 fullerene molecule have been also considered. The main goal is to determine the qualitative conditions for encapsulation of carbon atoms inside the fullerene molecule. It has been found that the predominant processes are scattering and adsorption of scattered carbon atoms with a minimal quantity of encapsulated atoms.

Critical charge transport networks in doped organic semiconductors

Intrinsic organic small molecule and polymer materials are insulators. The discovery that polymers can be made highly conductive by doping has therefore sparked strong interest in this novel class of conductors. More recently, efficient doping of small molecule materials has also been achieved and is now a key technology in the multi-billion dollar organic light emitting diode industry. Nevertheless, a comprehensive description of charge transport in the presence of doping is still missing for organic semiconductors with localized electronic states. Here, we present a theoretical and computational approach based on percolation theory and quantitatively predict experimental results from the literature for the archetype small molecule materials ZnPc, F8ZnPc and C60. We show that transport in the complex potential landscape that emerges from the presence of localized charges can be aptly analyzed by focusing on the network properties of transport paths instead of just the critical resistance. Specifically, we compute the activation energy of conductivity and the Seebeck energy and yield excellent agreement with experimental data. The previously unexplained increase of the activation energy at high doping concentrations can be clarified by our approach.

Fullerene Polymers: A Brief Review

This paper reviews the ways in which C60 and other fullerene molecules can be incorporated into polymeric structures. Firstly, polymers in which the fullerenes are incorporated into the structure by covalent or noncovalent bonding are discussed. These include “pearl necklace” structures, “charm bracelet” structures, organometallic polymers, crosslinked polymers, end-capped polymers, star-shaped polymers and supramolecular polymers. Secondly, all-carbon polymers, which are produced by fusing fullerenes together, are covered. The synthesis and properties of each class of fullerene polymer are outlined and the prospects for commercial applications considered.

C60 self-orientation on hexagonal boron nitride induced by intermolecular coupling

A deep grasp of the properties of the interface between organic molecules and hexagonal boron nitride (h-BN) is essential for the full implementation of these two building blocks in the next generation of electronic devices. Here, using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS), we report on the geometric and electronic features of C60 evaporated on a single layer of h-BN grown on a Rh(110) surface under ultra-high vacuum. Two different molecular assemblies of C60 on the h-BN/Rh(110) surface were observed. The first STM study at room temperature (RT) and at low temperatures (40 K) looked at the molecular orientation of C60 on a two-dimensional layered material. Intramolecular-resolution images demonstrate the existence of a phase transition of C60 over the h-BN/Rh(110) surface similar to that found on bulk solid C60. At RT molecules exhibit random orientations, while at 40 K such rotational disorder vanishes and they adopt a common orientation over the h-BN/Rh(110) surface. The decrease in thermal energy allows recognition between C60 molecules, and they become equally oriented in the configuration at which the van der Waals intermolecular interactions are optimized. Bias-dependent submolecular features obtained by means of high-resolution STM images are interpreted as the highest occupied and lowest unoccupied molecular orbitals. STS data showed that fullerenes are electronically decoupled from the substrate, with a negligible charge transfer effect if any. Finally, the very early stages of multilayer growth were also investigated.

Self-build of C60-C70 molecular heterojunctions on highly oriented pyrolytic graphite

Building a novel heterojunction with hybrid structures can create new physical properties and enable unique functionality. We investigated the build of C60-C70 heterojunction between C60 and C70 molecular layers by Scanning Tunnelling Microscopy (STM). The C60-C70 organic molecular heterojunction was successfully built by layer-by-layer growth method on the HOPG surface using ultra-high vacuum STM. Both molecules can rotate freely within their corresponding molecular layers at room temperature. When C70 molecules are deposited onto a preformed first layer of C60, the C70 molecules assemble into a close-packed second layer with a lattice-matched to the underlying C60 layer. The C70 molecules in the second layer adopt a standing up configuration with its long molecular axis perpendicular to the substrate which is accompanied by the elimination of the energy component associated with the rotation around the short molecular axis. C70 and C60 molecules at layers margins become mobile due to annealing processes and can jump up and form a new packing layer on its origin layer, C70 molecules remain as isolated molecules standing with their long axis perpendicular to the layers. The C60-C70 molecular heterojunctions allow building a lateral/vertical van der Waals heterojunctions.

Innovative Carbon Based Materials for Solid State Hydrogen Storage and Energy Storage

Alkali cluster-intercalated fullerides (ACIF) consist of crystalline nanostructures in which positively charged metal clusters are ionically bond to negatively charged C60 molecules, forming charge-transfer salts. These compounds have been recently investigated with renewed interest, appearing as a novel class of materials for hydrogen storage, thanks to their proven capability to uptake reversibly high amounts of hydrogen via a complex chemisorption mechanism. In this presentation, after a short summary on the hydrogen storage topic, the synthesis, the structural investigation, and the hydrogen storage properties of Li, Na, and mixed Li-Na clusters intercalated fullerides belonging to the families NaxLi12-xC60 (0 ≤ x ≤ 12) and NaxLi6-xC60 (0 ≤ x ≤ 6) will be presented. By manometric and thermal analyses, it has been proved that C60 covalently binds up to 5.5 wt% H2 at moderate temperature and pressure, thanks to the catalytic effect of the intercalated alkali clusters. Moreover, the destabilizing effect of Na in the co-intercalated NaxLi6-xC60 compounds leads to an improvement of the hydrogen-sorption kinetics by about 70%, linked to a decrease in the desorption enthalpy from 62 to 44 kJ/mol H2. The addition of Pt and Pd nanoparticles to Li fullerides increases up to 5.9 wt% H2 the absorption performances and of about 35 % the absorption rate. The ammonia storage properties of Li6C60 have also been investigated, resulting in quite appealing. Being the price of C60 quite high, cheaper C based materials are under examination. Porous biochar from agricultural waste is giving interesting results as electrode materials for high-performance supercapacitors.

Theoretical Prediction on a Novel Reduction-Responsive Nanoring Having a Disulfide Group for Facile Encapsulation and Release of Fullerenes C60 and C70

In this work, a novel reduction-responsive disulfide bond-containing cycloparaphenylene nanoring molecule (DSCPP) with a pyriform shape has been designed. In addition, the interactions between the designed nanoring (host) and fullerenes C60 and C70 (guests) were investigated theoretically at the M06-2X/6-31G(d,p) and M06-L/MIDI! levels of theory. By analyzing geometric characteristics and host–guest binding energies, it is revealed that the designed DSCPP is an ideal host molecule of guests C60 and C70. DSCPP presents excellent elastic deformation during the encapsulation of C60 and C70. The high binding energies suggest that both DSCPP⊃C60 and DSCPP⊃C70 (∼92 and 118 kJ·mol–1 at the M06-2X/6-31G(d,p) level of theory) are stable host–guest complexes, and the guest C70 is more strongly encapsulated than C60 in the gas phase. The thermodynamic information indicates that the formation of the two host–guest complexes is thermodynamically spontaneous. In addition, the frontier molecular orbital (FMO) features and intermolecular weak interaction region between DSCPP and fullerenes gusts are discussed to further understand the structures and properties of the DSCPP⊃fullerene systems. Finally, the ring-opening mechanism of the DSCPP under reduction conditions is investigated.

Direct transformation of AgNO3 complex encapsulated Fullerene (C60) microcrystal on solid silver Nitrate Crystal without organic Ligands

We observed the unusual crystal transformation from solid AgNO3 to Ag(I)‐encapsulated fullerene (C60) microcrystal by a coordination‐driven crystallization, when casting C60 solution on AgNO3 crystal. The strong binding of Ag+‐C60 ruptures electrostatic interactions within AgNO3 lattice, forming a binary hybrid material, which was characterized by XRD, Raman spectroscopy and mass spectrometry. Our results support the fact that AgNO3 crystal can directly interact with fullerene C60 molecules, other than through solvated metal cations. Two major factors, namely sturdy Ag+‐olefin interaction and an enclosed cage effect play the dominating roles in crystal transformation. Adding to the regular solution‐based crystallization, this facial protocol is expected to render an additional dimension in fabrication of exohedral metallofullerene architecture, regardless of solubility of metal cation in anti‐solvent.