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It was shown that the chain length of the aliphatic substituent in the alkyl derivative of 3-(1-indenyl)propionic acid of C60 and C70 fullerenes affects the efficiency of photovoltaic cells with the PTB7-Th:fullerene-derivative bulk heterojunction (BHJ). A series of new C60 and C70 fullerene derivatives containing the n-alkyl ester of 3-(1-indenyl)propionic acid were synthesized using the Diels–Alder reaction. The synthesized fullerene derivatives had aliphatic side chains of 4 to 12 carbon atoms in the ester group. All synthesized compounds were successfully used in the BHJ solar cell, achieving energy conversion efficiencies (PCEs) ranging from 0.8 to 3.9%. We observed an increase in solar cell open-circuit voltage of 30 meV for the 60IPH acceptor material. Long aging measurements of the solar cells with the new fullerene derivatives show long lifetimes for C60 derivatives and shorter for C70. The lifetime significantly depends on the aliphatic chain length. The longest 80% decay period, T80, was about 200 days. [ABSTRACT FROM AUTHOR]

Encouraged by the promising performance of C60-graphene single-molecule transistors observed in experiments, two types of Fen/C60-GNR (n = 2 and 4 and GNR = graphene nanoribbon) molecules with Fe atoms sandwiched between the upper and lower GNR layers were designed and their electronic and transport properties were investigated by employing density functional theory (DFT) and nonequilibrium Green's function (NEGF) methods. Adding the Fe atoms induces high spin magnetism in the systems. Within the considered bias, almost all Fe2/C60-GNR devices generate double NDR peaks, and some of the Fen/C60-GNR devices (n = 2 and 4) possess a large peak-to-valley current ratio R = Ipeak/Ivalley (>400), implying potential applications in developing on–off–on/off–on–off current switches. The NDR character originates from the crossing of the frontier molecular orbitals. In addition, these systems show distinct spin-polarized transport characteristics, with up-spin channels displaying higher conductivity than down-spin pathways. The spin filter efficiency (SFE) oscillates up and down as bias is scanned for almost all devices, suggesting the possibility of designing on–off–on/off–on–off current switches as well as up–down spin switches. All these findings provide guidance for exploring single molecular devices with promising properties combined with graphene, fullerenes, and transition metals. [ABSTRACT FROM AUTHOR]

Although fullerene derivatives such as [6,6]‐phenyl‐C61/C71‐butyric acid methyl ester (PC61BM/PC71BM) have dominated the the photoactive acceptor materials in bulk heterojunction organic solar cells (OSCs) for decades, they have several drawbacks such as weak absorption, limited structural tunability, prone to aggregation, and high costs of production. Constructing non‐fullerene small molecules with three‐dimensional (3D) molecular geometry is one of the strategies to replace fullerenes in OSCs. In this study, a 3D molecule, contorted hexa‐cata‐hexabenzocoronene tetra perylenediimide (HBC‐4‐PDI), was designed and synthesized. HBC‐4‐PDI shows a wide and strong light absorption in the whole UV‐vis region as well as suitable energy levels as an acceptor for OSCs. More importantly, the 3D construction effectively reduced the self‐aggregation of c‐HBC, leading to an appropriate scale phase separation of the blend film morphology in OSCs. A preliminary power conversion efficiency of 2.70 % with a champion open‐circuit voltage of 1.06 V was obtained in OSCs with HBC‐4‐PDI as the acceptor, which was the highest among the previously reported OSCs based on c‐HBC derivatives. The results indicated that HBC‐4‐PDI may serve as a good non‐fullerene acceptor for OSCs. [ABSTRACT FROM AUTHOR]

The thin film deposition engineering of layer‐by‐layer (LbL) non‐fullerene organic solar cells (OSCs) favors vertical phase distributions of donor:acceptor (D:A), effectively boosting the power conversion efficiency (PCE). However, previous deposition strategies mainly aimed at optimizing the morphology of LbL films, and paid limited attention to the reproducibility of device performance. To achieve high device performance and maintain reproducibility, a strategy for hierarchical morphology manipulation in LbL OSCs is developed. A series of LbL devices are fabricated by introducing vacuum‐assisted molecular drift treatment (VMDT) to the donor or acceptor layer individually or simultaneously to elucidate the functionalities of this treatment. Essentially, the VMDT provides an extended drift driving force to manipulate the donor and acceptor molecules, resulting in a well‐defined vertical phase distribution and ordered molecular packing. These enhancements facilitate improvement in the D:A interface area and charge transport channel, ultimately contributing to impressive PCEs of 19.18% from 18.27% in the LbL devices. More importantly, using VMDT overcomes the notorious batch‐dependent and heat treatment degradation issues of OSCs, leading to excellent batch‐to‐batch reproducibility and enhanced stability of the devices. This reported method provides a promising strategy available for industrial and laboratory use to controllably manipulate the morphology of LbL OSCs. [ABSTRACT FROM AUTHOR]

Tuning the morphology through processing additives represents one of the most promising strategies to boost the performance of organic solar cells (OSCs). However, it remains unclear how oligothiophene‐based solid additives influence the molecular packing and performance of OSCs. Here, two additives namely 2T and 4T, are introduced into state‐of‐the‐art PM6:Y6‐based OSCs to understand how they influence the film formation process, nanoscale morphology, and the photovoltaic performance. It is found that the 2T additive can improve the molecular packing of both donor polymer and non‐fullerene acceptor, resulting in lower Urbach energy and reduced energy loss. Furthermore, the blend film with 2T treatment displays enhanced domain purity and a more favorable distribution of the acceptor and donor materials in the vertical direction, which can enhance charge extraction efficiency while simultaneously suppressing charge recombination. Consequently, OSCs processed with 2T additive realize a promising efficiency of 18.1% for PM6:Y6‐based devices. Furthermore, the general applicability of the additive is demonstrated, and an impressive efficiency of 18.6% for PM6:L8‐BO‐based OSCs is achieved. These findings highlight that the uncomplicated oligothiophenes have excellent potential in fine‐adjustment of the active layer morphology, which is crucial for the future development of OSCs. [ABSTRACT FROM AUTHOR]

Aqueous supercapacitors have occupied a significant position among various types of stationary energy storage equipment, while their widespread application is hindered by the relatively low energy density. Herein, N/F co-doped carbon materials activated by manganese clusters (NCM) are constructed by the straightforward experimental routine. Benefiting from the elevated conductivity structure at the microscopic level, the optimized NCM-0.5 electrodes exhibited a remarkable specific capacitance of 653 F g−1 at 0.4 A g−1 and exceptional cycling stability (97.39% capacity retention even after 40,000 cycles at the scanning rate of 100 mV s−1) in a neutral 5 M LiCl electrolyte. Moreover, we assembled an asymmetric device pairing with a VOx anode (NCM-0.5//VOx), which delivered a durable life span of 95% capacity retention over 30,000 cycles and an impressive energy density of 77.9 Wh kg−1. This study provides inspiration for transition metal element doping engineering in high-energy storage equipment. [ABSTRACT FROM AUTHOR]

Carbon materials derived from fullerene are reported recently with unique structures and properties. However, only micrometer size samples can be obtained that limits the studying and exploration for membrane applications. Here, the preparation of a centimeter‐size nanoporous amorphous carbon monolayer is reported by rapid pyrolyzing a Langmuir–Blodgett film of fullerene. The sample is fully characterized and the results indicate that the amorphous carbon monolayer derived from fullerene is metastable and insulating. The ionic transmembrane transport study demonstrates that the membrane is porous and cation selective with a selectivity of 26%. This work provides new insights into the controlled synthesis of large‐size metastable amorphous carbon monolayer. [ABSTRACT FROM AUTHOR]

The striking aesthetic appeal of fullerene‐like clusters has captured the interest of researchers. Nevertheless, the assembly of fullerene‐like polyoxovadanadate (POV) cages remains a significant challenge due to the scarcity of suitable pentagonal motif. Herein, we have successfully synthesized the first fullerene‐like all‐inorganic POV cage, {(V2O)V30Nb12O102(H2O)12} (V30Nb12), by introducing Nb into the POVs. V30Nb12 is assembled by 12 heterometallic {(Nb)V5} pentagons through sharing V centers with Ih symmetry, reminiscent of C60. To our knowledge, the fullerene‐like V30Nb12 not only represents the highest‐nuclearity POV cage but also stands as the first niobovanadate cluster. Notably, V30Nb12 exhibits excellent solution stability, as confirmed by ESI‐MS, FT‐IR and UV/Vis spectra. As there is no protection organic ligand on its outer surface, V30Nb12 can be further modified with Cu‐complexes to form a fullerene‐like cluster based zigzag chain (Cu−V30Nb12). [ABSTRACT FROM AUTHOR]

A 14‐electron ternary anionic CBe2H5− cluster containing a planar tetracoordinate carbon (ptC) atom is designed herein. Remarkably, it can be stabilized by only two beryllium atoms with both π‐acceptor/σ‐donor properties and two hydrogen atoms, which means that the conversion from planar methane (transition state) to ptC species (global minimum) requires the substitution of only two hydrogen atoms. Moreover, two ligand H atoms exhibit alternate rotation, giving rise to interesting dynamic fluxionality in this cluster. The electronic structure analysis reveals the flexible bonding positions of ligand H atoms due to C−H localized bonds, highlighting the rotational fluxionality in the cluster, and two CBe2 3c–2e delocalized bonds endow its rare 2σ/2π double aromaticity. Unprecedentedly, the fluxional process exhibits a conversion in the type of bonding (σ bond↔π bond), which is an uncommon fluxional mechanism. The cluster can be seen as an attempt to apply planar hypercoordinate carbon species to molecular motors. [ABSTRACT FROM AUTHOR]

The remarkable structures of open-cage fullerenes with functionalization on the outer surface and an accessible inner void make them interesting ligands for reactions with metal complexes. The behaviors of open-cage fullerenes in reactions with various metal complexes are examined and compared to the corresponding reactions with intact fullerenes. The structural results from X-ray diffraction are emphasized. Open-cage fullerenes frequently undergo unanticipated structural changes such as carbon–carbon bond cleavage upon reactions with metal complexes. Much more remains to be learned about the possibility of inserting metal ions larger than Li+ into the interior void of these open-cage fullerenes and about the effects of redox reactions on metal complexes of open-cage fullerenes. [ABSTRACT FROM AUTHOR]

Pyrene‐based molecules are being explored as prospective fullerene‐free acceptors for organic solar cells (OSCs), due to their easy accessibility, structural planarity, and excellent electron delocalization. In this work, we successfully designed and analyzed pyrene‐based acceptor materials (QL1–QL8) to investigate their photophysical and electro‐optical parameters. Various geometric parameters were computed at the MPW1PW91/6‐31G(d,p). Advanced quantum chemical approaches were employed to characterize the molecules. All the tailored molecules (QL1–QL8) exhibit a lower bandgap than the reference (R), signifying their superiority. Among these, QL8 was found to have a maximum absorption (λmax) at 791.37 nm and an optical bandgap (ELUMO − EHOMO) minimum of 2.11 eV. Redshifted absorption spectra are observed in both gaseous and solvent phases for all the designed (QL1–QL8) molecules in contrast to R. Among these, QL4 exhibits the highest light harvesting efficiency (0.9826), and open‐circuit voltage. A detailed donor–acceptor investigation of QL8/PBDB‐T revealed the marvelous charge switching at the donor–acceptor interface. The approach used in this study is anticipated to facilitate the manufacturing of highly efficient OSC molecules. [ABSTRACT FROM AUTHOR]

Asphaltene is often regarded as an undesirable by‐product of petroleum processing, possesses vast reserves with little market value. The typical routes of consuming asphaltene, namely burning and landfilling, pose significant environmental challenges. In this study, low‐value asphaltene is converted into high‐value ethylated carbon clusters (ECC) using a supercritical ethanol technique. The resulting ECC powder demonstrates promising properties for high density polyethylene (HDPE) composite applications. The effects of incorporating ECC on the mechanical, gas barrier, and anti‐aging properties of the composite are investigated. Results show that a 1 wt.% ECC led to a 4.2% and 43.5% increase in tensile strength and elongation at break, a reduction of 45.8% and 30.7% in oxygen and carbon dioxide permeability. Furthermore, ECC exhibits effective UV spectrum absorption and conversion in the wavelength range of 400–600 nm, providing protection against UV spectrum damage to HDPE. The incorporation of ECC not only enhances the properties of polymer composites but also sequesters carbon within the polymer matrix, enabling the valorization of asphaltene while mitigating environmental impact. [ABSTRACT FROM AUTHOR]

Mycobacterium tuberculosis and nontuberculous mycobacteria such as Mycobacterium abscessus cause diseases that are becoming increasingly difficult to treat due to emerging antibiotic resistance. The development of new antimicrobial molecules is vital for combating these pathogens. Carbon nanomaterials (CNMs) are a class of carbon‐containing nanoparticles with promising antimicrobial effects. Fullertubes (C90) are novel carbon allotropes with a structure unique among CNMs. The effects of fullertubes on any living cell have not been studied. In this study, we demonstrate that pristine fullertube dispersions show antimicrobial effects on Mycobacterium smegmatis and M. abscessus. Using scanning electron microscopy, light microscopy, and molecular probes, we investigated the effects of these CNMs on mycobacterial cell viability, cellular integrity, and biofilm formation. C90 fullertubes at 1 µM inhibited mycobacterial viability by 97%. Scanning electron microscopy revealed that the cell wall structure of M. smegmatis and M. abscessus was severely damaged within 24 h of exposure to fullertubes. Additionally, exposure to fullertubes nearly abrogated the acid‐fast staining property of M. smegmatis. Using SYTO‐9 and propidium iodide, we show that exposure to the novel fullertubes compromises the integrity of the mycobacterial cell. We also show that the permeability of the mycobacterial cell wall was increased after exposure to fullertubes from our assays utilizing the molecular probe dichlorofluorescein and ethidium bromide transport. C90 fullertubes at 0.37 µM and C60 fullerenes at 0.56 µM inhibited pellicle biofilm formation by 70% and 90%, respectively. This is the first report on the antimycobacterial activities of fullertubes and fullerenes. Significance statement: The recently isolated fullertubes (C90) are carbon nanoparticles with tubular molecular structures and hemispherical end caps and their effects on any living cell have not been investigated. We show that the novel fullertubes inhibit mycobacterial cell growth and cause physical damage to the cell envelope in Mycobacterium smegmatis and in Mycobacterium abscessus, an infectious organism of clinical importance. We also show that fullertubes and fullerenes inhibit biofilm formation which is a key phenotype of mycobacterial pathogenesis. [ABSTRACT FROM AUTHOR]

In the past decade, nanozymes - a unique class of nanomaterials with inherent enzyme-mimetic properties - have fascinated researchers, revealing unexpected enzyme-like activity of nanomaterials previously considered biologically inert. In particular, as metal-free catalyst for biological processes, carbon-based nanozymes have grown in popularity due to their exceptional physical and chemical characteristics. So far, a variety of carbon-based nanozymes with various structures such as fullerene, graphene oxide, carbon dot, carbon nanotube, and carbon nanosphere have been reported possessing a wide range of enzyme-like properties. However, the structure-activity relationship of the carbon-based nanozymes have not yet been comprehensively discussed. In this review, we thoroughly examine the recent findings on the structure-activity connection of carbon nanozymes, in an effort to comprehend the underlying mechanism of carbon nanozymes and throw light on the future direction of the systematic design and construction of functionally specific carbon nanozymes. We also will address the broad range of applications of carbon nanozymes from in vitro detection to replacing specific enzymes in living systems. [ABSTRACT FROM AUTHOR]

A complete analysis of the existing methods of synthesis of polyhydroxylated fullerenes using direct chemical interaction, as well as alternative methods of creation has been carried out in order to identify the optimal methods of obtaining, for their implementation in various technological and biomedical fields. The scientific literature on this field of research is summarized and classified, and a comparative assessment of the efficiency and feasibility of practical implementation of the developed synthesis methods is given on the basis of a comprehensive review of literature and patent documents. [ABSTRACT FROM AUTHOR]

The antimicrobial application of carbon nanomaterials, such as carbon nanotubes (CNTs), capped CNTs, CNT2–5, C60, C70, HO-C60, [C60]2, and [C60]3 fullerenes, is increasing, owing to their low cytotoxicity properties compared to other nanomaterials such as metallic nanoparticles. Enhanced mechanical properties and antibacterial activity can be caused by the incorporation of CNTs in 3-dimensional (3D) printed nanocomposites (NCs). The interruption of the bacterial membrane resulting from the cylindrical shape and high aspect ratio properties has been found to be the most prominent antibacterial mechanism of CNTs. However, the unraveling interaction of CNTs, capped CNTs, CNT2–5, C60, C70, HO-C60, [C60]2, and [C60]3 fullerenes with virulence factors of the main bacterial pathogenesis has not yet been understood. Therefore, in the present study, interactions of these carbon-based nanomaterials with the eight virulence factors, including protein kinase A and (ESX)-secreted protein B of Mycobacterium tuberculosis, pseudomonas elastase and exotoxin A of Pseudomonas aeruginosa, alpha-hemolysin and penicillin-binding protein 2a of Staphylococcus aureus, and shiga toxin 2a and heat-labile enterotoxin of Escherichia coli, were evaluated with the molecular docking method of AutoDock Vina. This study disclosed that the binding affinity was highest for CNT2–5 and [C60]3 toward alpha-hemolysin, with binding energies of −32.7 and −26.6 kcal/mol, respectively. The stability of the CNT2–5–alpha-hemolysin complex at different times was obtained according to the normal mode analysis of ElNémo and iMOD servers. [ABSTRACT FROM AUTHOR]

This review describes the progress of the gas-phase study of endometallofullerenes (EMFs) by mass spectrometry and theoretical calculation over the past 15 years. The attention herein focuses on the gas-phase syntheses, reactions, and generation mechanisms of some novel EMF ions, along with their structures and properties. The highlighted new species include EMFs with small-size carbon cages of C2n (n < 60), multiple metal atoms (Mx@C2n, x ≥ 3), late transition metals, and encaged ionic bonds. Furthermore, the gas-phase experimental and calculational supports for top-down or bottom-up models are summarized and discussed. These gas-phase results not only provide experimental evidence for the existence of related novel EMF species and possible synthesis methods for them, but they also provide new insights about chemical bonds in restricted space. In addition, the opportunities and further development directions faced by gas-phase EMF study are anticipated. [ABSTRACT FROM AUTHOR]

Vacuum-sublimation cryogenic deposition (VS-CD) method is successfully applied to produce fullerene water colloidal solution (FWCS): the melting of the solid phase of the mixture obtained by joint condensation of C60 fullerene and water vapors onto a surface cooled with liquid nitrogen results in formation of a stable colloidal solution. The results of the FWCS characterization by means of Raman, IR, and UV-Vis spectroscopy and their comparison with known literature data on hydrated fullerenes give the authors an opportunity to make conclusion that the FWCS contains C60@{H2O}n complexes of hydrated C60 fullerene. Transmission electron microscopy shows that the VS-CD-produced material contains predominantly small C60 clusters of about 2–5 nm size, while mass spectrometry with laser desorption/ionization has demonstrated the presence of pure fullerene C60 and the absence of any products of its transformation. The performed analysis reveals a close similarity of the stable C60@{H2O}n complexes generated by VS-CD with the previously known highly hydrophilic hydrated fullerene obtained by ultrasonication method. [ABSTRACT FROM AUTHOR]

Under the background of rapid global economic transformation, the influence of economic policy uncertainty (EPU) has penetrated all fields of production and life. It is significant to study how it affects the regional carbon emission intensity for regional sustainable development. Based on the data from 30 provinces from 2004 to 2017, this paper takes a complete account of spatial heterogeneity and the dynamic impact of economic policy uncertainty on carbon emission intensity using a spatial econometric model. The main conclusions are as follows: (1) For more than ten years, there have been significant differences and instabilities in economic policy uncertainty and carbon emission intensity in different regions of China. (2) China's local carbon emission intensity shows an objective spatial aggregation effect, which is significant, spatially auto-correlated and clustered. (3) Based on the national level, economic policy uncertainty will significantly increase the regional carbon emission intensity. Additionally, economic policy uncertainty has a significant positive spatial spillover effect, which may increase carbon emission intensity in neighboring provinces. (4) Based on the provincial level, the impact of economic policy uncertainty on carbon emission intensity in various regions is significantly positive, with the most significant impact on the western region. Based on the above conclusions, the paper proposes policy suggestions to stabilize the regional carbon emission intensity in all directions. [ABSTRACT FROM AUTHOR]

[Display omitted] Using inexhaustible solar energy to drive efficient light-driven thermocatalytic CO 2 reduction by CH 4 (DRM) is an attractive approach that can synchronously reduce the greenhouse effect and convert solar energy into fuels. However, it is often limited by the intense light intensity required to produce high fuel production rates, and the catalyst deactivation due to severe carbon deposition generated from side reactions. Herein, a nanostructure of alumina-cluster-modified Ni nanoparticles supported on Al 2 O 3 nanorods (ACM-Ni/Al 2 O 3) was synthesized, displaying good catalytic performance under focused UV–vis-IR illumination. By light-driven thermocatalytic DRM on ACM-Ni/Al 2 O 3 at a reduced light intensity of 76.9 kW m−2, the high fuel production rates of H 2 (r H2, 65.7 mmol g−1 min−1) and CO (r CO, 78.8 mmol g−1 min−1), as well as an efficient light-to-fuel efficiency (η , 26.3 %) are achieved without additional heating. The r H2 and r CO of light-driven thermocatalysis are 2.9 and 1.9 times higher, respectively, compared to conventional thermocatalysis at the same temperature. We have discovered that high light-driven thermocatalytic activity originates from the photoactivation effect, significantly reducing the apparent activation energy and facilitating C* oxidation as a decisive step in DRM. ACM-Ni/Al 2 O 3 possesses excellent durability and exhibits an extremely low coking rate of 4.40 × 10−3 g c g catalyst −1 h−1, which is 26.8 times lower than that of the reference sample without Al 2 O 3 cluster modification (R-Ni/Al 2 O 3). This is owing to a decrease in activation energies (E a) of C* oxidation and an increase in E a of C* polymerization by the surface modification of Ni nanoparticles with Al 2 O 3 clusters, effectively inhibiting carbon deposition. [ABSTRACT FROM AUTHOR]

This study aimed to develop sorbitol fuel cell catalysts for cathode and anode fuels by synthesizing AgV2O5/C, AgMnO2/C, and PdCeO2/C catalysts. The physical characteristics of the catalysts were analyzed using SEM and EDS. The results showed that the prepared catalysts were small, lumpy, and densely clustered on the carbon surface with small particles. The electrochemical characteristics of the oxidation of alkaline fuels using sorbitol as fuel were investigated by assessing sorbitol concentration ratios of 0.1, 0.2, 0.3, 0.4 and 0.5 per 0.1 M alkaline KOH solution through cyclic voltammetry. The PdCeO2/C catalyst at a concentration of 0.1 M sorbitol solution exhibits the highest potential difference at the potential range of - 0.5 to 0.5 V, resulting in a maximum current density of 0.2 mA/cm². The AgV2O5/C and AgMnO2/C catalysts were tested in the reduction reaction, and the concentration ratios of sorbitol solution per 0.1 M alkaline KOH solution varied from 0.1 to 0.5 M. The results demonstrated a decrease in activity in the catalyst reduction reaction as the sorbitol solution concentration increased, indicating a potential correlation with enhanced oxidation resistance. [ABSTRACT FROM AUTHOR]

The modification of fused rings in the central backbone, side chains, and end groups of the non‐fullerene acceptor (NFA) for organic solar cells (OSCs) can modulate properties and photovoltaic performance. In order to investigate the effect of fused rings and side chains on photovoltaic performance, PBDB‐T is selected as electron donor and IDTIC, IDIC, IDIC‐PhC6, IDIC‐C4Ph, 4TIC, ITIC‐OE, IDTTIC, ITC6‐IC, ITIC, and C8‐ITIC are selected as NFAs. Based on quantum chemistry calculations, the geometries, electronic structures, excitation properties, excited‐state lifetimes, and electrostatic potentials (ESPs) of the monomer and the PBDB‐T:NFA complexes are studied, and the rate constants of charge transfer (CT), exciton dissociation (ED) and charge recombination (CR) processes are analyzed. The results show that the increase of fused‐ring in NFA's backbone by substituting phenyl or thienyl with bithiophene can elevate the highest occupied molecular orbital energies, reduce the gap of frontier molecular orbital energies, induce red‐shift of absorption spectrum, increase CT energy, improve CT and ED rates. This work provides a detailed understanding of tuning optoelectronic properties and photovoltaic performance by modifying NFA's side chains and extending backbones. [ABSTRACT FROM AUTHOR]

The effect of carbon doping on the structural and physicochemical properties of B12N12‐xCx [4, 6]‐fullerenes (0 ≤ x ≤ 6) (BNFs) is studied in the frame of the density functional theory. All non‐symmetry related isomers are modeled. Although carbon doping reduces the cohesive energy of the BNFs, most of them remain stable. It is found that the location of carbon atoms in the lowest‐energy isomers follows a definite sequence as the doping level increases. The results indicate that substitutional carbon lowers the gap energy and chemical hardness of BNFs, but it increases their electronegativity and electrophilicity index. Particularly, carbon doping makes BNFs more susceptible to nucleophilic attacks. Additionally, the charge redistribution and structural asymmetry generated by carbon doping endows BNFs with polar character. A dipole alignment parameter is introduced to elucidate some correlation between the atomic arrangement and the polarity of the systems. While carbon doping enhances the capability of BNFs to interact with other chemical species, possible toxicity concerns are highlighted. Finally, possible fingerprints to identify successful carbon doping through infrared and UV–vis spectroscopy are proposed. [ABSTRACT FROM AUTHOR]

In the case of certain chemical compounds, especially organic ones, electrons can be delocalized between different atoms within the molecule. These resulting bonds, known as resonance bonds, pose a challenge not only in theoretical descriptions of the studied system but also present difficulties in simulating such systems using molecular dynamics methods. In computer simulations of such systems, it is often common practice to use fractional bonds as an averaged value across equivalent structures, known as a resonance hybrid. This paper presents the results of the analysis of five forms of C60 fullerene polymorphs: one with all bonds being resonance, three with all bonds being integer (singles and doubles in different configurations), one with the majority of bonds being integer (singles and doubles), and ten bonds (within two opposite pentagons) valued at one and a half. The analysis involved the Shannon entropy value for bond length distributions and the eigenfrequency of intrinsic vibrations (first vibrational mode), reflecting the stiffness of the entire structure. The maps of the electrostatic potential distribution around the investigated structures are presented and the dipole moment was estimated. Introducing asymmetry in bond redistribution by incorporating mixed bonds (integer and partial), in contrast to variants with equivalent bonds, resulted in a significant change in the examined observables. [ABSTRACT FROM AUTHOR]

Different carbon-based nanomaterials (fullerenes, graphene, SWCNTs, and SWCNT-COOH) were tested as additives in a base mineral oil, SN150; rapeseed oil (RSO); and a 50/50 by volume blend of the two using an HFRR (high-frequency reciprocating rig) tester for coefficient of friction (COF) and wear scar diameter (WSD) determinations and a four-ball tester for welding point determinations. The concentrations considered for the HFRR tests were 0.1, 0.5, 1, and 2 wt.%, while the concentration considered for the welding point tests was 0.5 wt.%. The results of the welding point tests showed that the addition of different nanoparticles made it so that welding occurred at much lower pressures compared to the pure oils. This is due to the hardness of the nanoparticles, which increases the local temperature and pressure at the contact points between them and the surfaces, causing welding to occur much sooner. The results of the HFRR tests showed a possible synergistic effect between the fullerenes and SWCNT-COOH and the oil blend, which may be attributed to possible interactions that occurred at a molecular level between the nanoparticles and the different molecules of the oil blend. [ABSTRACT FROM AUTHOR]

Electrochemical production of hydrogen peroxide (H2O2) via the two-electron (2e−) pathway of oxygen reduction reaction (ORR) supplies an auspicious alternative to the current industrial anthraquinone process. Nonetheless, it still lacks efficient electrocatalysts to achieve high ORR activity together with 2e− selectivity simultaneously. Herein, a boron-doped defective nanocarbon (B-DC) electrocatalyst is synthesized by using fullerene frameworks as the precursor and boric oxide as the boron source. The obtained B-DC materials have a hierarchical porous structure, befitting boron dopants, and abundant topological pentagon defects, exhibiting a high ORR onset potential of 0.78 V and a dominated 2e− selectivity (over 95%). Remarkably, when B-DC electrocatalyst is employed in a real device, it achieves a high H2O2 yield rate (247 mg·L−1·h−1), quantitative Faraday efficiency (~ 100%), and ultrafast organic pollutant degradation rate. The theoretical calculation reveals that the synergistic effect of topological pentagon defects and the incorporation of boron dopants promote the activation of the O2 molecule and facilitates the desorption of oxygen intermediate. This finding will be very helpful for the comprehension of the synergistic effect of topological defects and heteroatom dopants for boosting the electrocatalytic performance of nanocarbon toward H2O2 production. [ABSTRACT FROM AUTHOR]

Upon conducting an investigation, the functionality of the smallest fullerene (C20) as a nano-carrier for the dacarbazine anticancer drug was thoroughly examined using density functional theory simulations. The adsorption energies obtained from the simulations indicate that the interaction of dacarbazine with C20 is indeed feasible under experimental conditions. Furthermore, the Natural Bond Orbital (NBO) analysis revealed that no chemical bond is formed between dacarbazine and the nanostructure, indicating that the interaction is purely a result of physisorption. Additionally, the results from the frontier molecular orbital analysis demonstrated a significant decrease in the bandgap of the fullerene by 44.469% to 4.967 eV. This reduction in bandgap suggests that C20 has the potential to serve as an ideal nanocarrier for the delivery of dacarbazine. Moreover, the values obtained for the dipole moment and chemical hardness further support the suitability of C20 as a nano-carrier for the delivery of dacarbazine. In conclusion, the findings from the density functional theory simulations provide compelling evidence for the potential use of C20 as an effective nano-carrier for the delivery of the dacarbazine anticancer drug. These results pave the way for further exploration and development of C20-based nanomaterials for drug delivery applications. [ABSTRACT FROM AUTHOR]

Significant carbon emissions, a key contributor to global climate warming, pose risks to ecosystems and human living conditions. It is crucial to monitor the spatial and temporal patterns of carbon emissions at the county level to reach the goals of carbon peak and neutrality. This study examines carbon emissions and economic and social problems data from 89 counties in Zhejiang Province. It employs analytical techniques such as LISA time path, spatio-temporal transition, and standard deviational ellipse to investigate the trends of carbon emissions from 2002 to 2022. Furthermore, it utilizes the GTWR model to evaluate the factors that influence these emissions on a county scale. The findings reveal the following: (1) The LISA time path analysis indicates a pronounced local spatial structure in the distribution of carbon emissions in Zhejiang Province from 2002 to 2022, characterized by increasing stability, notable path dependency, and some degree of spatial integration, albeit with a diminishing trend in overall integration. (2) The LISA spatio-temporal transition analysis indicates significant path dependency or lock-in effects in the county-level spatial clustering of carbon emissions. (3) Over the period 2002–2022, the centroid of carbon emissions in Zhejiang's counties mainly oscillated between 120°55′15″ E and 120°57′01″ E and between 29°55′52″ N and 29°59′11″ N, with a general northeastward shift forming a "V" pattern. This shift resulted in a stable "northeast–southwest" spatial distribution. (4) Factors such as population size, urbanization rate, and economic development level predominantly accelerate carbon emissions, whereas industrial structure tends to curb them. It is crucial to customize carbon mitigation plans to suit the circumstances of each county. This study provides insight into the spatial and temporal patterns of carbon emissions at the county level in Zhejiang Province. It offers crucial guidance for developing targeted and practical strategies to reduce carbon emissions. [ABSTRACT FROM AUTHOR]

In the past five years, significant advancements in the development of novel conjugated polymer donors (D) and non‐fullerene acceptors (A), such as small molecules, have substantially boosted the power conversion efficiency of bulk heterojunction (BHJ) organic photovoltaics (OPVs) devices to over 19%. Recently, in the pursuit of broader impact and heightened efficiency for OPVs, an alternative processing approach has emerged; this approach involves a sequential deposition (SD) technique or a layer‐by‐layer method, creating active layers with p–i–n structures (p and n stand for D and A region, respectively; i stands for BHJ region). Notably, this SD method is particularly effective in semitransparent organic photovoltaics (ST‐OPVs), despite the material requirements it entails. SD‐processing methods enable the creation of vertical multiple junctions and controllable D/A interfaces, facilitating exciton dissociation and charge transport through a well‐designed pseudo p–i–n structure. Furthermore, ST‐OPVs can be integrated into building‐incorporated photovoltaic modules, offering potential applications in greenhouses and agricultural modernization. This integration allows for the comprehensive utilization of solar spectrum energy. In this review, current literature is consolidated on new materials, such as conjugated polymers and non‐fullerene small molecules as electron‐donating and electron‐withdrawing materials, aimed at high‐efficiency OPVs and ST‐OPVs with BHJ‐ and p–i–n structured active layers, and perspectives are offered for future developments. [ABSTRACT FROM AUTHOR]

In bulk-heterojunction (BHJ) organic photovoltaics (OPVs), non-fullerene acceptors (NFAs) have lately surpassed their fullerene counterparts in photovoltaic performance. This progress in NFA OPVs may encourage the exploration of varied OPV device architectures, either deviating from or expanding upon the fundamental BHJ structure. This study employs numerical simulations on PBDB-T:NCBDT OPVs using graphene oxide (GO) as the hole transport layer (HTL) to examine the influence of thickness, defect density, and interface defects on device performance. Following optimization, the device exhibits short-circuit current (JSC) of 27.92 mA cm−2, open-circuit voltage (VOC) of 1.08 V, fill factor (FF) of 72.57%, and power conversion efficiency (PCE) of 21.84%. These findings support the further development of NFA-OPVs employing GO as the HTL. [ABSTRACT FROM AUTHOR]

This review article is devoted to the colloidal properties of fullerene solutions. According to generally accepted understandings, all solvents in relations to fullerenes are divided into "good", "poor", and "reactive". We have consistently considered the state of fullerenes in these systems. In "good", predominantly non-polar aromatic solvents and CS2, non-equilibrium dissolution methods lead to the formation of colloidal aggregates, whereas the utilization of equilibrium methods results in the formation of molecular solutions. The latter, however, have some unusual properties; new results considered in this review confirm previously expressed ideas about colloidal properties of these solutions. In "poor" (polar) solvents, lyophobic colloidal systems appear. Both "bottom-up" and "top-down" methods of preparation are well documented in the literature. However, N-methylpyrrolidine-2-one, DMSO, and DMF dissolve fullerenes quite easily and with less energy consumption. These solvents can be considered a subset of "poor" solvents that have some features of being "reactive" at the expense of basic properties. New data confirm that hydrosols of fullerenes are typical hydrophobic colloids that obey the Schulze–Hardy rule and other regularities in the presence of electrolytes. Organosols in acetonitrile and methanol are much less stable with respect to the effects of electrolytes. This allows us to assume a non-DLVO stabilizing factor in the hydrosols. Accordingly, a new estimate of the Hamaker constant of fullerene–fullerene interaction is proposed. In DMSO and DMF, the coagulation of fullerene sols is hindered due to strong solvation with these basic solvents. [ABSTRACT FROM AUTHOR]

Organic thin films are of great interest due to their intriguing interfacial and functional properties, especially for device applications such as thin-film transistors and sensors. As their thickness approaches single nanometer thickness, characterization and interpretation of the extracted data become increasingly complex. In this study, plasma polymerization is used to construct ultrathin films that range in thickness from 1 to 20 nm, and time-of-flight secondary ion mass spectrometry coupled with principal component analysis is used to investigate the effects of film thickness on the resulting spectra. We demonstrate that for these cross-linked plasma polymers, at these thicknesses, the observed trends are different from those obtained from thicker films with lower degrees of cross-linking: contributions from ambient carbon contamination start to dominate the mass spectrum; cluster-induced nonlinear enhancement in secondary ion yield is no longer observed; extent of fragmentation is higher due to confinement of the primary ion energy; and the size of the primary ion source also affects fragmentation (e.g., Bi1 versus Bi5). These differences illustrate that care must be taken in choosing the correct primary ion source as well as in interpreting the data. [ABSTRACT FROM AUTHOR]

X-ray absorption spectroscopy (XAS) has the highest sensitivity for chemical element detection on surfaces. With this approach, small amounts of lanthanide-containing endofullerene molecules (Ho 3 N@C 80) have been measured by total electron yield at a low flux bending magnet beamline. The monolayer coverage is calibrated by extrapolating the signals of constant doses (3 × 10 14 cm − 2 ) of Ho ions implanted into SiO 2 with energies between 2 and 115 keV. At room temperature, the Ho XAS spectra of the molecules and implanted ions indicate trivalent but not identical Ho ground states. Still, this approach demonstrates a way for calibration of small coverages of molecules containing open core-shell elements. [ABSTRACT FROM AUTHOR]

Magnesium alloys are the lowest-density structural metals with a wide range of applications, such as aircraft skins, engine casings and automobile hubs. However, its low surface hardness and non-corrosion resistance in natural environments limit its wide range of applications. In this work, Si-DLC coatings (Si: 15 at.%) are fabricated on AZ91 alloy using a hollow cathode discharge combined with a DC bias voltage from 0 to −300 V to increase the deposition rate and modulate the structure and properties of the coatings. The Si interlayer with a thickness of around 0.6 µm is deposited first to enhance the adhesion. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy are used to investigate the effect of DC bias on the microstructure evolution of Si-DLC coatings. Meanwhile, corrosion and wear resistance of the coatings at various bias voltages have been investigated using electrochemical workstations and pin-on-desk wear testers. It is shown that the bias-free coating has a loose structure and is less resistant to corrosion and wear. The bias coating has a compact structure, small carbon cluster size, high chloride ion corrosion resistance, and high wear resistance against Al2O3 spheres. The corrosion potential of the coating bias at −300 V is −0.98 V, the corrosion current density is 1.35 × 10−6 A·cm−2, the friction coefficient is 0.08, and the wear rate is 10−8 orders of magnitude. The formation of SiC nanocrystals and high sp3-C, as well as the formation of transfer films on the surface of their counterparts, are the main reasons for the ultra-high wear resistance of the bias coatings. The wear rate, coefficient of friction, and corrosion rate of the coating are 0.0069 times, 0.2 times, and 0.0088 times that of the AZ91 alloy, respectively. However, the bias coating has only short to medium-term protection against the magnesium alloy and no long-term protection due to cracks caused by its high internal stress. [ABSTRACT FROM AUTHOR]

The use of carbon nanomaterials including fullerenes, carbon nanotubes, carbon nano-onions, carbon dots and carbon quantum dots for environmental applications has increased substantially. These nanoparticles are now used in the development of sensors and switches, in agriculture as smart fertilizers and in the biomedical realm for cancer therapy intervention, as antioxidants, in gene delivery and as theranostics. Here, we review the role of fullerenes as neuroprotectants. Their sp2 hybridized architectures and ability to intervene in the soluble-to-toxic transformation of amyloidogenic trajectories is highlighted here, along with other physico–chemical properties that impact interventional efficacy. Also highlighted are drawbacks that need to be overcome and future prospects. [ABSTRACT FROM AUTHOR]

Molecular iron phthalocyanine (FePc) bearing a single‐atom Fe–N4 moiety is a high‐profile non‐platinum catalyst toward the oxygen reduction reaction (ORR), but its unsatisfactory activity and inadequate stability hinder the practical application. Herein, a novel strategy by hybridizing FePc with fullerene‐derived intrinsic defect‐rich carbon to improve its ORR activity and stability is reported. Via alkali‐assisted thermal pyrolysis, C60 molecules are disintegrated into tiny fragments that then restructure into pentagon‐ and edge‐rich carbon (FC). Utilizing FC as a support of FePc leads to a significantly improved ORR activity compared to other supports including reduced graphene oxide and carbon nanotube that hold distinct structural features. The optimized FePc/FC with a Fe loading of 3 wt% presents a half‐wave potential of 0.917 V, far beyond that of Pt/C (0.846 V), via selective four‐electron ORR pathway and excellent stability under accelerated stress test. The practical applicability of FePc/FC is also demonstrated as a high‐performing cathode catalyst of aqueous zinc–air batteries. It is, for the first time, explicitly disclosed that strong interactions between FePc molecules and intrinsic carbon defects (e.g., pentagons and edges) not only strengthen the anchoring effect of supported FePc but also enhance the intrinsic ORR activity of single‐atom Fe–N4 sites.

The thermal stability of fullerenes plays a fundamental role in their synthesis and in their thermodynamic and kinetic properties. Here, we perform extensive molecular dynamics (MD) simulations using an accurate machine-learning-based Gaussian Approximation Potential (GAP-20) force field to investigate the energetic and thermal properties of the entire set of 1812 C 60 isomers. Our MD simulations predict a comprehensive and quantitative correlation between the relative isomerization energy distribution of the C 60 isomers and their thermal fragmentation temperatures. We find that the 1812 C 60 isomers span over an energetic range of over 400 kcal mol − 1 , where the majority of isomers (∼ 85%) lie in the range between 90 and 210 kcal mol − 1 above the most stable C 60 - I h buckminsterfullerene. Notably, the MD simulations show a clear statistical correlation between the relative energies of the C 60 isomers and their fragmentation temperature. The maximum fragmentation temperature is 4800 K for the C 60 - I h isomer and 3700 K for the energetically least stable isomer, where nearly 80% of isomers lie in a temperature window of 4000–4500 K. In addition, an Arrhenius-based approach is used to map the timescale gap between simulation and experiment and establish a connection between the MD simulations and fragmentation temperatures. [ABSTRACT FROM AUTHOR]

Modeling and understanding properties of materials from first principles require knowledge of the underlying atomistic structure. This entails knowing the individual chemical identity and position of all atoms involved. Obtaining such information for macro-molecules, nano-particles, and clusters and for the surface, interface, and bulk phases of amorphous and solid materials represents a difficult high-dimensional global optimization problem. The rise of machine learning techniques in materials science has, however, led to many compelling developments that may speed up structure searches. The complexity of such new methods has prompted a need for an efficient way of assembling them into global optimization algorithms that can be experimented with. In this paper, we introduce the Atomistic Global Optimization X (AGOX) framework and code as a customizable approach that enables efficient building and testing of global optimization algorithms. A modular way of expressing global optimization algorithms is described, and modern programming practices are used to enable that modularity in the freely available AGOX Python package. A number of examples of global optimization approaches are implemented and analyzed. This ranges from random search and basin-hopping to machine learning aided approaches with on-the-fly learnt surrogate energy landscapes. The methods are applied to problems ranging from supported clusters over surface reconstructions to large carbon clusters and metal-nitride clusters incorporated into graphene sheets. [ABSTRACT FROM AUTHOR]

The use of carbon nanomaterials including fullerenes, carbon nanotubes, carbon nano-onions, carbon dots and carbon quantum dots for environmental applications has increased substantially. These nanoparticles are now used in the development of sensors and switches, in agriculture as smart fertilizers and in the biomedical realm for cancer therapy intervention, as antioxidants, in gene delivery and as theranostics. Here, we review the role of fullerenes as neuroprotectants. Their sp2 hybridized architectures and ability to intervene in the soluble-to-toxic transformation of amyloidogenic trajectories is highlighted here, along with other physico–chemical properties that impact interventional efficacy. Also highlighted are drawbacks that need to be overcome and future prospects.

In order to study the thermal stability of fullerenes Cn (n = 28, 32, 44, 50) in a nitrogen medium during the transition from the condensed phase to the gas phase and further reactions in the vapor phase, the method of thermodynamic modeling was used. Based on the results of the calculation, chemical reactions in the Cn–N2 system were compiled and temperature intervals were identified for each reaction. In this work, a comparative study of the thermal stability ranges of Cn fullerenes in the condensed and gas phases has been carried out. As a result of heating, the physicochemical processes occurring in the carbon-nitrogen system are distinguished, which can be divided into three groups: reactions occurring in the condensed phase, between the condensed and gas phases, and sublimation with thermal dissociation. It is clearly demonstrated that with an increase in the number of carbon atoms in the condensed phase, fullerenes exhibit their thermal instability, in contrast to the solid solution of fullerenes. This study is one of a series of works devoted to the properties of nanoparticles in nitrogen atmosphere, which can be used in the development of new flame retardant compositions.

This review article is devoted to the colloidal properties of fullerene solutions. According to generally accepted understandings, all solvents in relations to fullerenes are divided into “good”, “poor”, and “reactive”. We have consistently considered the state of fullerenes in these systems. In “good”, predominantly non-polar aromatic solvents and CS2, non-equilibrium dissolution methods lead to the formation of colloidal aggregates, whereas the utilization of equilibrium methods results in the formation of molecular solutions. The latter, however, have some unusual properties; new results considered in this review confirm previously expressed ideas about colloidal properties of these solutions. In “poor” (polar) solvents, lyophobic colloidal systems appear. Both “bottom-up” and “top-down” methods of preparation are well documented in the literature. However, N-methylpyrrolidine-2-one, DMSO, and DMF dissolve fullerenes quite easily and with less energy consumption. These solvents can be considered a subset of “poor” solvents that have some features of being “reactive” at the expense of basic properties. New data confirm that hydrosols of fullerenes are typical hydrophobic colloids that obey the Schulze–Hardy rule and other regularities in the presence of electrolytes. Organosols in acetonitrile and methanol are much less stable with respect to the effects of electrolytes. This allows us to assume a non-DLVO stabilizing factor in the hydrosols. Accordingly, a new estimate of the Hamaker constant of fullerene–fullerene interaction is proposed. In DMSO and DMF, the coagulation of fullerene sols is hindered due to strong solvation with these basic solvents.

Anion–π catalysis, introduced in 2013, stands for the stabilization of anionic transition states on π-acidic aromatic surfaces. Anion–π catalysis on carbon allotropes is particularly attractive because high polarizability promises access to really strong anion–π interactions. With these expectations, anion–π catalysis on fullerenes has been introduced in 2017, followed by carbon nanotubes in 2019. Consistent with expectations from theory, anion–π catalysis on carbon allotropes generally increases with polarizability. Realized examples reach from enolate addition chemistry to asymmetric Diels–Alder reactions and autocatalytic ether cyclizations. Currently, anion–π catalysis on carbon allotropes gains momentum because the combination with electric-field-assisted catalysis promises transformative impact on organic synthesis.

Understanding the fundamental mechanisms that underlie the synthesis of fullerene molecules in the interstellar medium (ISM) and in the environments of astrophysical objects is an open question. In this regard, using classical molecular dynamics, we demonstrate the possibility of in situ formation of fullerene molecules, such as C60 from graphite, which is known to occur in the ISM, in particular, circumstellar environments. Specifically, when graphite is subjected to thermal and mechanical stimuli that are typical of circumstellar shells, we find that the graphite sheet edges undergo significant restructuring and curling, leading to edge-induced interlayer-interactions and formation of mechanically strained five-membered-ring structural units. These units serve as precursors for the formation of fullerene structures, such as pristine and metastable C60 molecules. The pathways leading to molecular C60 formation consist of a series of steps that involve bond-breakage and subsequent local rearrangement of atoms, with the activation energy barriers of the rate-limiting step(s) being comparable to the energetics of Stone–Wales rearrangement reactions. The identified chemical pathways provide fundamental insights into the mechanisms that underlie C60 formation. Moreover, they clearly demonstrate that top-down synthesis of C60 from graphitic sources is a viable synthesis route at conditions pertaining to circumstellar matter. [ABSTRACT FROM AUTHOR]

Recurrent fluorescence (RF) from isolated carbon clusters containing between 24 and 60 atoms is theoretically investigated as a function of internal energy, cluster size, and structural features. The vibrational relaxation kinetics and the associated IR emission spectra are determined by means of a Monte Carlo approach with vibrational density of states computed in the harmonic approximation. RF is generally found to be highly competitive with vibrational emission. The behaviors predicted for clusters of various sizes and archetypal structures indicate that the IR emission spectra are strongly influenced by RF, an energy gap law being obtained for the evolution of the RF rate constant depending on the electronic excitation state. The present results are relevant to the photophysics of the interstellar medium and could contribute to elucidating the carriers of the extended red emission bands and the continuum emission lying below the aromatic infrared bands believed to originate from mixed aromatic–aliphatic compounds. [ABSTRACT FROM AUTHOR]

We present a methodology that, for the first time, allows rigorous quantum calculation of the inelastic neutron scattering (INS) spectra of a triatomic molecule in a nanoscale cavity, in this case, H2O inside the fullerene C60. Both moieties are taken to be rigid. Our treatment incorporates the quantum six-dimensional translation–rotation (TR) wave functions of the encapsulated H2O, which serve as the spatial parts of the initial and final states of the INS transitions. As a result, the simulated INS spectra reflect the coupled TR dynamics of the nanoconfined guest molecule. They also exhibit the features arising from symmetry breaking observed for solid H2O@C60 at low temperatures. Utilizing this methodology, we compute the INS spectra of H2O@C60 for two incident neutron wavelengths and compare them with the corresponding experimental spectra. Good overall agreement is found, and the calculated spectra provide valuable additional insights. [ABSTRACT FROM AUTHOR]

Photonic Doppler velocimetry and digital high-speed shadowgraphy have been used to characterize the chemical reaction zone parameters of pressed trinitrotoluene (TNT) samples with an initial density of 1.568 g cm − 3 . Comparison of the nanosecond time-resolved particle velocity histories of the free surfaces of detonating charges in air and light vacuum and of the interfaces between TNT detonation products and lithium fluoride or polymethyl methacrylate windows allow one to bracket the von Neumann spike pressure between 24.8 and 28.8 GPa. Our velocity waveforms confirm the two-step reaction pathway already observed in TNT, triaminotrinitrobenzene (TATB), and nitromethane, with a first fast energy release over 80 ns followed by a slower release over 250 additional ns. We consider the end of the first release zone as the locus of the Chapman–Jouguet (CJ) state, and the CJ pressure thus lies between 17.6 and 17.7 GPa. The energy release is not completed in this Jouguet plane but only after about ≈ 280 ns when the carbon cluster formation process ends. This corresponds to both the end of the slow release part of the interface velocity profiles and to the moment at which the free surface velocity profiles reach their maximum. Our shadowgraphy images confirm that carbon formation occurs very rapidly after the detonation breakout, in good agreement with previous time-resolved small-angle x-ray scattering measurements. The comparison with similar results previously obtained on TATB allows one to further highlight their similarities, which mainly result from their excess carbon production at late times. [ABSTRACT FROM AUTHOR]

Electronic spectra are measured for mass-selected C 2 n + (n = 6–14) clusters over the visible and near-infrared spectral range through resonance enhanced photodissociation of clusters tagged with N2 molecules in a cryogenic ion trap. The carbon cluster cations are generated through laser ablation of a graphite disk and can be selected according to their collision cross section with He buffer gas and their mass prior to being trapped and spectroscopically probed. The data suggest that the C 2 n + (n = 6–14) clusters have monocyclic structures with bicyclic structures becoming more prevalent for C 22 + and larger clusters. The C 2 n + electronic spectra are dominated by an origin transition that shifts linearly to a longer wavelength with the number of carbon atoms and associated progressions involving excitation of ring deformation vibrational modes. Bands for C 12 + , C 16 + , C 20 + , C 24 + , and C 28 + are relatively broad, possibly due to rapid non-radiative decay from the excited state, whereas bands for C 14 + , C 18 + , C 22 + , and C 26 + are narrower, consistent with slower non-radiative deactivation. [ABSTRACT FROM AUTHOR]