Single Fullerene Research Articles

First-principles study of electrochemical H2O2 production on Pd-B40 single-atom catalyst

Hydrogen peroxide (H2O2), a versatile green compound, is increasingly in demand. The electrochemical two-electron oxygen reduction reaction (2e− ORR) is a simple and environmentally friendly substitute method to the traditional anthraquinone oxidation method for H2O2 production. This study systematically investigates the 2e− ORR process on single transition metal atom-loaded boron fullerene (M − B40) using density functional theory calculations. In evaluating the stability of the catalysts, we found that Au, Pd, Pt, Rh, and Ir atoms adsorbed on hexagonal or heptagonal sites of B40 exhibit good stability. Among these, Pd-modified B40 heptagonal cavity (Pd-B40-heptagonal) demonstrates an ideal Gibbs free energy change for OOH* (4.49 eV) and efficiently catalyzes H2O2 production at a low overpotential (0.27 V). Electronic structure analysis reveals that electron transfer between Pd-B40-heptagonal and adsorbed O2 facilitates O2 activation. Additionally, the high 2e− ORR activity of Pd-B40-heptagonal is attributed to electron transfer from the Pd-d orbitals to the π* anti-bonding of p orbitals of OOH*, moderately activating the O-O bond. This study offers valuable understanding designing high-performance electrocatalysts for 2e− ORR.

Mixed Cluster Ions of Magnesium and C60.

Magnesium clusters exhibit a pronounced nonmetal-to-metal transition, and the neutral dimer is exceptionally weakly bound. In the present study, we formed pristine Mgnz+ (n = 1-100, z = 1-3) clusters and mixed (C60)mMgnz+ clusters (m = 1-7, z = 1, 2) upon electron irradiation of neutral helium nanodroplets doped with magnesium or a combination of C60 and magnesium. The mass spectra obtained for pristine magnesium cluster ions exhibit anomalies, consistent with previous reports in the literature. The anomalies observed for C60Mgn+ strongly suggest that Mg atoms tend to wet the surface of the single fullerene positioning itself above the center of a pentagonal or hexagonal face, while, for (C60)mMgnz+, the preference for Mg to position itself within the dimples formed by fullerene cages becomes apparent. Besides doubly charged cluster ions, with the smallest member Mg22+, we also observed the formation of triply charged ions Mgn3+ with n > 24. The ion efficiency curves of singly and multiply charged ions exhibit pronounced differences compared to singly charged ions at higher electron energies. These findings indicate that sequential Penning ionization is essential in the formation of doubly and triply charged ions inside doped helium nanodroplets.

Local heating and Raman thermometry in a single molecule.

Because of the nonequilibrium nature of thermal effects at the nanoscale, the characterization of local thermal effects within a single molecule is highly challenging. Here, we demonstrate a way to characterize the local thermal properties of a single fullerene (C60) molecule during current-induced heating processes through tip-enhanced anti-Stokes Raman spectroscopy. Although the measured vibron populations are far from equilibrium with the environment, we can still define an "effective temperature (Teff)" statistically via a Bose-Einstein distribution, suggesting a local equilibrium within the molecule. With increased current heating, Teff is found to rise up to about 1150 K until the C60 cage is decomposed. Such a decomposition temperature is similar to that reported for ensemble C60 samples, thus justifying the validity of our methodology. Moreover, the possible reaction pathway and product can be identified because of the chemical sensitivity of Raman spectroscopy. Our findings provide a practical method for noninvasively detecting the local heating effect inside a single molecule under nonequilibrium conditions.

DEPOSITION OF FULLERITES C60 ON A SOLID SUBSTRATE TO FORM A FILM

The use of C60 fullerites to create films on the surface of a solid substrate can be used not only to create coatings, but also to modify the surface layer of the substrate, which from a practical point of view can be in demand in such sectors of the economy as machine and instrument engineering. To analyze the process of formation of fullerite films on the substrate surface, a computer experiment was carried out, but the behavior of not a single fullerite or fullerene, as it was implemented in previous works of the authors, but a significant number of C60 fullerites deposited in the modeling area over a certain time interval and forming a "flow" was modeled. The substrate of the solid was an iron crystal Fe(100). The substrate temperature in the study was kept constant at the following values – 300 K, 700 K, 1150 K. The initial parameters of each individual fullerite were determined stochastically within the specified limits. The software package used to conduct the described computer experiment was – LAMMPS. The interaction of the atoms of the system with each other, during the simulation, was determined by the multiparticle potential (MEAM is a modified submerged atom method). The main result of the conducted computer experiment is that it was possible to simulate the deposition of C60 fullerites with the formation of a film on a solid substrate. The main regularities of the interaction of fullerite as a whole and fullerenes forming it, both with the substrate and with other fullerites forming the film, were revealed. And the analysis of changes in temperature and potential energy of the system, both during the deposition of fullerites and after its completion, allows us to talk about the stability of the resulting fullerite – substrate system.

Functionalized Fullerene for Inhibition of SARS‐CoV‐2 Variants (Small 15/2023)

Inhibition of SARS-CoV-2 Variants In the article number 2206154, Ievgen S. Donskyi and co-workers describe effective SARS-CoV-2 inhibitor. Low molecular weight polyglycerol sulfate works in tandem with a single hydrophobic fullerene to prevent the infection in vitro. Investigated through plaque reduction assays, microscale thermophoresis (MST) binding studies, and molecular dynamics (MD) simulations, fullerene appears to nestle in to a solvent accessible hydrophobic pocket on the S1 spike protein.

The largest fullerene.

Fullerenes are lowest energy structures for gas phase all-carbon particles for a range of sizes, but graphite remains the lowest energy allotrope of bulk carbon. This implies that the lowest energy structure changes nature from fullerenes to graphite or graphene at some size and therefore, in turn, implies a limit on the size of free fullerenes as ground state structures. We calculate this largest stable single shell fullerene to be of size N = 1 × 104, using the AIREBO effective potential. Above this size fullerene onions are more stable, with an energy per atom that approaches graphite structures. Onions and graphite have very similar ground state energies, raising the intriguing possibility that fullerene onions could be the lowest free energy states of large carbon particles in some temperature range.

Field emission microscope for a single fullerene molecule

Applying strong direct current (DC) electric fields on the apex of a sharp metallic tip, electrons can be radially emitted from the apex to vacuum. Subsequently, they magnify the nanoscopic information on the apex, which serves as a field emission microscope (FEM). When depositing molecules on such a tip, peculiar electron emission patterns such as clover leaves appear. These phenomena were first observed seventy years ago. However, the source of these emission patterns has not yet been identified owing to the limited experimental information about molecular configurations on a tip. Here, we used fullerene molecules and characterized the molecule-covered tip by an FEM. In addition to the experiments, simulations were performed to obtain optimized molecular configurations on a tip. Both results indicate that the molecules, the source of the peculiar emission patterns, appear on a molecule layer formed on the tip under strong DC electric fields. Furthermore, the simulations revealed that these molecules are mostly isolated single molecules forming single-molecule-terminated protrusions. Upon the excellent agreements in both results, we concluded that each emission pattern originates from a single molecule. Our work should pave the way to revive old-fashioned electron microscopy as a powerful tool for investigating a single molecule.

Magnetic response properties of carbon nano-onions.

The magnetic response of a number of double- and triple-layer carbon nano-onions (CNOs) is analyzed by calculating the magnetically induced current density and the induced magnetic field using the pseudo-π model. Qualitatively the same magnetic response was obtained in calculations at the all-electron level. The calculations show that the CNOs exhibit strong net diatropic (paratropic) ring currents when the external magnetic field points perpendicularly to one of the six-membered (five-membered) rings. They are deshielded inside and shielded outside the CNO; the latter dominates for larger CNOs. The magnetic response originates from a combination of spherical paratropic current densities on the inside of each carbon layer and diatropic current densities on the outside of them. The quantitative differences in the aromaticity of the CNOs as compared to single fullerenes are discussed in terms of ring-current strengths. The magnetic response of some of the CNOs is approximately the sum of the magnetic response of the individual layers, whereas deviations are significant for CNOs containing C80. For the largest CNOs, the deviation from the sum of the fullerene contributions is larger, especially when the external magnetic field is perpendicular to a six-membered ring.

Slow spin relaxation in single endohedral fullerene molecules

Well-protected magnetization, tunable quantum states, and long spin-relaxation time are desired for the use of magnetic molecules in spintronics and quantum information technologies. In this work, endohedral fullerene molecules $\mathrm{M}@{\mathrm{C}}_{28}$ with different transition-metal cores were explored through systematic first-principles calculations and spin dynamics analyses. Many of them have bias-tunable structure, stable magnetization, and sizable magnetic anisotropy energy. Furthermore, some of them may have spin-relaxation time up to several milliseconds for their quantum spin states at high temperature (\ensuremath{\sim}10 K) after full consideration of spin-vibration couplings. Our results suggest that these $\mathrm{M}@{\mathrm{C}}_{28}$ provide a rich pool of single-molecule magnets for diverse applications.

Understanding the effect of the double side chain fullerene derivative as third component materials on the charge dynamics and photovoltaic performance

In this study, ternary organic solar cells (OSCs) are fabricated with the PBDB-T-2F as a polymer donor and NCBDT-4Cl as a fullerene-free acceptor, double side chain fullerene derivative NC70BA as a third component material and single side chain fullerene PC71BM as reference third component materials. The NC70BA-based ternary OSCs exhibit the highest PCE of 13.82%, which is 10% higher than that of PBDB-T-2F:NCBDT-4Cl binary OSCs and slightly higher than PC71BM-based ternary OSCs (13.24%). Detailed studies suggest that the shallow LUMO levels and double side chain for NC70BA is beneficial to broaden energy bandgap and improve compatibility, which is enhancing JSC and FF value. This work suggests that double side chain fullerene derivative NC70BA as third component materials is a promising way to finely tune the detailed photovoltaic parameters and further improve the photovoltaic performance of OSCs.

High-efficiency single and tandem fullerene solar cells with asymmetric monofluorinated diketopyrrolopyrrole-based polymer

Design and synthesis of low bandgap (LBG) polymer donors is inevitably challenging and their processability from a non-halogenated solvent system remains a hurdle to overcome in the area of high-performance polymer solar cells (PSCs). Due to a high aggregation tendency of LBG polymers, especially diketopyrrolopyrrole (DPP)-based polymers coupled with bithiophenes in the polymer backbones, their widespread adoption in non-halogenated solvent-processed PSCs has been limited. Herein, a novel LBG DPP-based polymer, called PDPP4T-1F with asymmetric arrangement of fluorine atom, has been successfully synthesized and showed an outstanding power conversion efficiency (PCE) of 10.10% in a single-junction fullerene-based PSCs. Furthermore, an impressive PCE of 13.21% has been achieved in a tandem device from a fully non-halogenated solvent system, which integrates a wide bandgap PDTBTBz-2F polymer in the bottom cell and LBG PDPP4T-1F polymer in the top cell. The achieved efficiency is the highest value reported in the literature to date in fullerene-based tandem PSCs. We found that a uniformly distributed interpenetrating fibril network with nano-scale phase separation and anisotropy of the polymer backbone orientation for efficient charge transfer/transport and suppressed charge recombination in PDPP4T-1F-based PSCs led to outstanding PCEs in single and tandem-junction PSCs.

A three-shell supramolecular complex enables the symmetry-mismatched chemo- and regioselective bis-functionalization of C60.

Molecular Russian dolls (matryoshkas) have proven useful for testing the limits of preparative supramolecular chemistry but applications of these architectures to problems in other fields are elusive. Here we report a three-shell, matryoshka-like complex-in which C60 sits inside a cycloparaphenylene nanohoop, which in turn is encapsulated inside a self-assembled nanocapsule-that can be used to address a long-standing challenge in fullerene chemistry, namely the selective formation of a particular fullerene bis-adduct. Spectroscopic evidence indicates that the ternary complex is sufficiently stable in solution for the two outer shells to affect the addition chemistry of the fullerene guest. When the complex is subjected to Bingel cyclopropanation conditions, the exclusive formation of a single trans-3 fullerene bis-adduct was observed in a reaction that typically yields more than a dozen products. The selectivity facilitated by this matryoshka-like approach appears to be a general phenomenon and could be useful for applications where regioisomerically pure C60 bis-adducts have been shown to have superior properties compared with isomer mixtures.

Real-Time Video Imaging of Mechanical Motions of a Single Molecular Shuttle with Sub-Millisecond Sub-Angstrom Precision

Abstract Miniaturized machines have open up a new dimension of chemistry, studied usually as an average over numerous molecules or for a single molecule bound on a robust substrate. Mechanical motions at a single molecule level, however, are under quantum control, strongly coupled with fluctuations of its environment — a system rarely addressed because an efficient way of observing the nanomechanical motions in real time is lacking. Here, we report sub-millisecond sub-Å precision in situ video imaging of a single fullerene molecule shuttling, rotating, and interacting with a vibrating carbon nanotube at 0.625 milliseconds(ms)/frame or 1600 fps, using an electron microscope, a fast camera, and a denoising algorithm. We have achieved in situ observation of the mechanical motions of a molecule coupled with vibration of a carbon nanotube with standard error as small as 0.9 millisecond in time and 0.01 nm in space. We have revealed rich molecular dynamics, where motions are non-linear, stochastic and often non-repeatable, and a work and energy relationship at a molecular level previously undetected by time-averaged measurements or microscopy. The molecular video recording at a 1600-fps rate exceeds by 100 times the previous records of continuous recording of molecular motions.

Nanoarchitectonics of Nanoporous Carbon Materials in Supercapacitors Applications.

High surface area and large pore volume carbon materials having hierarchical nanoporous structure are required in high performance supercapacitors. Such nanoporous carbon materials can be fabricated from organic precursors with high carbon content, such as synthetic biomass or agricultural wastes containing cellulose, hemicellulose, and lignin. Using recently developed unique concept of materials nanoarchitectonics, high performance porous carbons with controllable surface area, pore size distribution, and hierarchy in nanoporous structure can be fabricated. In this review, we will overview the recent trends and advancements on the synthetic methods for the production of hierarchical porous carbons with one- to three-dimensional network structure with superior performance in supercapacitors applications. We highlight the promising scope of accessing nanoporous graphitic carbon materials from: (i) direct conversion of single crystalline self-assembled fullerene nanomaterials and metal organic frameworks, (ii) hard- and soft-templating routes, and (iii) the direct carbonization and/or activation of biomass or agricultural wastes as non-templating routes. We discuss the appealing points of the different synthetic carbon sources and natural precursor raw−materials derived nanoporous carbon materials in supercapacitors applications.

Double fullerene cathode buffer layers afford highly efficient and stable inverted planar perovskite solar cells

Abstract Fullerene derivatives especially [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) with strong electron-accepting abilities have been commonly implemented as indispensable cathode buffer layers (CBLs) of inverted (p-i-n) planar perovskite solar cells (iPSCs) to facilitate electron transport. However, only a single fullerene CBL is typically used in iPSC devices, resulting in interfacial energy offset between fullerene CBL and metal cathode and consequently insufficient electron transport. Herein, we synthesized a novel bis-dimethylamino-functionalized fullerene derivative (abbreviated as PCBDMAM) and applied it as an auxiliary fullerene interlayer atop of PCBM to form a PCBM/PCBDMAM double fullerene CBL, leading to dramatic enhancement of both efficiency and ambient stability of iPSC devices. Incorporation of PCBDMAM interlayer facilitates the formation of interfacial dipole layer between PCBM and Ag cathode, resulting in decrease of the work function of the Ag cathode. As a result, the CH3NH3PbI3 (MAPbI3) iPSC devices based on PCBM/PCBDMAM double fullerene CBL exhibit the highest power conversion efficiency (PCE) of 18.11%, which is drastically higher than that of the control device based on single PCBM CBL (14.21%) and represents the highest value reported for double fullerene CBL-based iPSC devices. Moreover, due to the higher hydrophobicity of PCBDMAM than PCBM, iPSC devices based on PCBM/PCBDMAM double fullerene CBL shows an enhanced ambient stability, retaining 67% of the initial PCE after storage 1440 h exposure under the ambient atmosphere without any encapsulation, whereas only 43% retaining was achieved for the control device based on single PCBM CBL.

Molecular dynamics investigation on the nano-mechanical behaviour of C60 fullerene and its crystallized structure.

C60 fullerene has been utilized in various applications, including low friction and wear coatings, due to its unique molecular structure. In this work, molecular dynamics simulations were conducted to assess the nano-mechanical behaviour of a single C60 fullerene and its crystallized structure. A single C60 model and a model of a face-centred cubic structured C60 crystal with a one-unit-cell thickness were prepared for compression and unloading simulations based on the adaptive intermolecular reactive empirical bond-order potential for carbon. Force-displacement curves and molecule-averaged virial stresses were obtained during the simulation. The models applied during the compression and unloading processes were visualized to confirm the deformation behaviour. Both the single and crystal C60 models showed a perfectly reversible deformation before the point of force decrease that occurred during compression. In particular, the face-centred cubic structure of the crystal C60 model was severely altered during compression before the individual C60 molecules experienced permanent deformation. The maximum values of the normal virial stress in the compression direction before the permanent deformation of the molecules were almost same for both the single and crystallized models.

Fullerenes as solitons in chiral model of graphene

Taking into account the sp2- hybridization effect for valence electrons in carbon atoms, we introduce a unitary matrix U as an order parameter and suggest a scalar chiral model of graphene for the description of graphene-like configurations. Using the well-known hedgehog ansatz for modeling Fullerene C60, we estimate the polarizability of a single Fullerene specie in a uniform external electric field. Finally, we use this result for calculating the parameters of the van der Waals potential for the two interacting Fullerene species.

Rotational switches in the two-dimensional fullerene quasicrystal.

One of the essential components of molecular electronic circuits are switching elements that are stable in two different states and can ideally be switched on and off many times. Here, distinct buckminsterfullerenes within a self-assembled monolayer, forming a two-dimensional dodecagonal quasicrystal on a Pt-terminated Pt3Ti(111) surface, are identified to form well separated molecular rotational switching elements. Employing scanning tunneling microscopy, the molecular-orbital appearance of the fullerenes in the quasicrystalline monolayer is resolved. Thus, fullerenes adsorbed on the 36 vertex configuration are identified to exhibit a distinctly increased mobility. In addition, this finding is verified by differential conductance measurements. The rotation of these mobile fullerenes can be triggered frequently by applied voltage pulses, while keeping the neighboring molecules immobile. An extensive analysis reveals that crystallographic and energetic constraints at the molecule/metal interface induce an inequality of the local potentials for the 36 and 32.4.3.4 vertex sites and this accounts for the switching ability of fullerenes on the 36 vertex sites. Consequently, a local area of the 8/3 approximant in the two-dimensional fullerene quasicrystal consists of single rotational switching fullerenes embedded in a matrix of inert molecules. Furthermore, it is deduced that optimization of the intermolecular interactions between neighboring fullerenes hinders the realization of translational periodicity in the fullerene monolayer on the Pt-terminated Pt3Ti(111) surface.

Supramolecular Fullerene Sponges As Catalytic Masks for Regioselective Functionalization of C <sub>60</sub>

Isomer-pure poly-functionalizalized fullerenes are required to boost the development of fullerene chemistry in any field, and specifically in solar cell design. Easy-accessible mono-functionalized fullerenes are mainly used in organic- or perovskite-based solar cells, due to the hampered accessibility to pure-isomer poly-adduct derivatives. In a general basis, multi-adduct mixtures with uncontrolled regioselectivity are obtained, and chromatographic purification is prohibitively costly and time-consuming to be used in the production of solar cells. Moreover, single isomer poly-functionalized fullerenes are only accessible via stoichiometric, multistep paths entailing protecting-unprotecting sequences. Herein, a nanocapsule is used as a supramolecular mask to exert full control on the reactivity and the equatorial regioselectivity of Bingel-Hirsch cyclopropanation reactions of confined fullerene guests. Thus, equatorial bis-, tris- and tetrakis-C60 homo-adducts are exclusively obtained in a stepwise manner, completely avoiding over functionalization (always observed in bulk solution) and holding precise control on the number of additions. Regioselectivity is strictly dictated by the four cross-shaped open windows in the tetragonal prismatic supramolecular container. Furthermore, isomer-pure equatorial hetero-tetrakis-adducts or hetero-Th-hexakis-adducts are synthesized at will in one-pot synthesis for the first time. Remarkably, a synthetically useful biphasic protocol is designed to achieve selective and quantitative formation of exclusively tetrakis-adducts using catalytic amounts of nanocapsule. Therefore, the confinement control imposed by the capsule’s cavity conforms a unique practical strategy to infer regio-control to the synthesis of fullerene equatorial poly-adducts. This work provides a synthetically valuable path to produce a plethora of new pure-isomer poly-functionalized C60-based compounds, as candidates for testing in solar cell devices and for biomedical applications.

Quaternary polymer solar cells with over 13% efficiency enabled by improving film-morphologiesviabinary mixed fullerene additive

The use of binary mixed fullerene additive outperforms the use of single fullerene additive.