C60 In Solution Research Articles

Co-Solvent Effect in the Processing of the Perovskite:Fullerene Blend Films for Electron Transport Layer-Free Solar Cells

An understanding of the improvements achieved in the use of cosolvents for methylammonium lead triiodide (MAPbI3):C70 blend films (MAPbI3:C70) processing is presented. A comparative study using aromatic (i.e., o-xylene and o-dichlorobenzene) and aliphatic (i.e., methylcyclohexane and chlorocyclohexane) cosolvents proves the nature of the cosolvent interacting with fullerene to be determining for achieving enhanced devices. UV–vis spectra of the different C70 solutions suggest a major impact of the solute–aromatic solvent interactions on the optoelectronic properties. The effect of aromatic and aliphatic solvents in the electronic structure of C70 crystals, obtained from the different solutions, is indeed demonstrated by electron energy loss spectroscopy. Morphological studies show elimination of pinholes (field emission scanning electron microscopy) and different nanometric features related to fullerene (atomic force microscopy) in MAPbI3:C70 blend films processed using aromatic cosolvents. A severe quenc...

Design of High-Density Helical Polymer Brush on Silica Nanoparticles for the Size Recognition of Fullerene Molecules.

High-density syndiotactic poly(methyl methacrylate) (st-PMMA) brushes form a helical structure and encapsulate fullerene molecules in their helical cavities, leading to a PMMA brush/fullerene inclusion complex. The brushes recognize the size of guest molecules and spontaneously adapt their helical diameter to the guest molecules. Both polymer brush/C60 and polymer brush/C70 inclusion complex on the flat substrate were characterized on the basis of grazing incidence wide-angle X-ray diffraction (GIWAXD) measurements, and it is revealed that the main chains oriented perpendicular to the substrate. Moreover, high-density st-PMMA brushes grafted onto nanoparticles efficiently separate C70 molecules from the mixture of C60 and C70 solution. Even after 5× repeating process, the selectivity for C70 molecules remains at 99%.

Complexes of guest–host type between C60 and group 9 metalloporphyrins

Half-sandwich iridium(iii) and cobalt(iii) porphyrin-C60 co-crystals, C60·IrIII(ttp)Ph and C60·CoIII(ttp)Ph/C7H8, and triangular-sandwich C60·3IrIII(ttp)Ph, where ttp = tetra-p-tolylporphyrinato dianion, were synthesized.

Controlling the growth of fullerene C60 cones under continuous flow.

Micromixing of an o-xylene solution of C60 with N-N-dimethylformamide (DMF) at room temperature under continuous flow in a vortex fluidic device (VFD) results in the formation of symmetrical right cones in high yield with diameters 0.5 to 2.5 μm, pitch angle 25° to 55° and wall thickness 120 to 310 nm. Their formation is in the absence of surfactants and any other reagents, and is scalable. The cones are formed at specific operating parameters of the VFD, including rotational speed, flow rate and concentration, and varying these results in other structures such as grooved fractals. Other aromatic solvents in place of o-xylene results in the formation of rods, spicules and prisms, respectively for m-xylene, p-xylene and mesitylene.

Highly Crystalline Mesoporous C60 with Ordered Pores: A Class of Nanomaterials for Energy Applications.

Highly ordered mesoporous C60 with a well-ordered porous structure and a high crystallinity is prepared through the nanohard templating method using a saturated solution of C60 in 1-chloronaphthalene (51 mg mL-1 ) as a C60 precursor and SBA-15 as a hard template. The high solubility of C60 in 1-chloronaphthalene helps not only to encapsulate a huge amount of the C60 into the mesopores of the template but also supports the oligomerization of C60 and the formation of crystalline walls made of C60 . The obtained mesoporous C60 exhibits a rod-shaped morphology, a high specific surface area (680 m2 g-1 ), tuneable pores, and a highly crystalline wall structure. This exciting ordered mesoporous C60 offers high supercapacitive performance and a high selectivity to H2 O2 production and methanol tolerance for ORR. This simple strategy could be adopted to make a series of mesoporous fullerenes with different structures and carbon atoms as a new class of energy materials.

Highly Crystalline Mesoporous C60 with Ordered Pores: A Class of Nanomaterials for Energy Applications

AbstractHighly ordered mesoporous C60 with a well‐ordered porous structure and a high crystallinity is prepared through the nanohard templating method using a saturated solution of C60 in 1‐chloronaphthalene (51 mg mL−1) as a C60 precursor and SBA‐15 as a hard template. The high solubility of C60 in 1‐chloronaphthalene helps not only to encapsulate a huge amount of the C60 into the mesopores of the template but also supports the oligomerization of C60 and the formation of crystalline walls made of C60. The obtained mesoporous C60 exhibits a rod‐shaped morphology, a high specific surface area (680 m2 g−1), tuneable pores, and a highly crystalline wall structure. This exciting ordered mesoporous C60 offers high supercapacitive performance and a high selectivity to H2O2 production and methanol tolerance for ORR. This simple strategy could be adopted to make a series of mesoporous fullerenes with different structures and carbon atoms as a new class of energy materials.

Synthesis of bipyramidal gold nanoparticle-[C60]fullerene nanowhisker composites and catalytic reduction of 4-nitrophenol

ABSTRACTThe seed solution was prepared by dissolving hydrogen tetrachloroaurate(III) trihydrate (HAuCl4·3H2O), trisodium citrate dihydrate (C6H5Na3O7·2H2O), and sodium borohydride (NaBH4) in distilled water. The resulting reddish-purple seed solution was stirred for 3 h at room temperature. The growth solution was prepared by mixing hydrogen tetrachloroaurate(III) trihydrate (HAuCl4·3H2O), cetyltrimethylammonium bromide (CTAB, (C16H33)N(CH3)3Br), silver nitrate (AgNO3), hydrochloric acid (HCl), and ascorbic acid (C6H8O6) in distilled water. Subsequently, 100 μL of this seed solution was transferred into 10 mL of the growth solution. The mixed solution was maintained at 30 °C for 3 h to obtain a solution of bipyramidal gold nanoparticles. The bipyramidal gold nanoparticle-[C60] fullerene nanowhisker composites were synthesized by applying the liquid-liquid interfacial precipitation (LLIP) method to a saturated solution of C60 in toluene, the solution of bipyramidal gold nanoparticles, and isopropyl alcohol. The prepared bipyramidal gold nanoparticle-[C60] fullerene nanowhisker composites were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. The catalytic activity of these composites was confirmed in the reduction of 4-nitrophenol by UV-Vis spectroscopy.

Investigation of structural morphology and electrical properties of graphene-C60 hybrids

In this work, the authors report on the electrophoretic deposition of C60 on graphene. The graphene films were characterized using Raman spectroscopy and scanning electron microscopy, and electrical contacts were made with the graphene nanomembranes using a viscoelastic stamping method. Different concentration solutions of C60 were prepared and deposited on graphene substrates using the electrophoretic deposition technique. Electronic characterization of the structures was conducted before and after the attachment of C60. Optical absorption of different concentrations of C60 was measured. A comparative study was carried out to analyze the resistivity and conductivity as a result of the interaction with a Si/SiO2 substrate. Our results suggest that graphene based C60 structures are attractive as flexible transparent electrodes and are excellent electron accepting/charge transport materials for the construction of efficient photovoltaic devices.

Orientational order in the stable buckminster fullerene solvate C60·2CBr2H2

Crystals of the solvate C60·2CBr2H2 (monoclinic C2/m), which is stable in air, were grown by slow evaporation of solutions of C60 in CBr2H2 at room temperature. The high enthalpy change for the complete desolvation process, 54.9 kJ mol−1 of solvent, as well as the relatively large negative excess volume of −49.6 A3 indicate the presence of strong intermolecular interactions between C60 and CBr2H2. The strong intermolecular interactions are consistent with an overall orientational order for the C60 and the CBr2H2 molecules in the solvate as found by the Rietveld refinement of its crystal structure.

Expanded Rosarin: A Versatile Fullerene (C60) Receptor.

An expanded rosarian (P3P6) with a bowl-like conformation has been prepared and characterized in a one-pot procedure that involves condensing a bispyrrole pyridine precursor (P1P2) with benzaldehyde, followed by oxidation. Single crystal X-ray diffraction analysis reveals a bowl-like conformation in the solid state with an upper rim diameter defined by the meso-phenyl substituents of ca. 13.5 Å and a depth of roughly 6.3 Å. P3P6 forms both 1:1 and 2:1 complexes with C60 in the solid state. DFT reveals similar energies for the two binding modes. A 1:1 binding stoichiometry dominates in 1,2-dichlorobenzene-d4 at the millimolar concentrations dictated by solubility consideration. The solution phase interactions between rosarian and C60 were studied using 1H NMR, UV-vis, and femtosecond transient absorption spectroscopies in 1,2-dichlorobenzene-d4 or toluene. To our knowledge, this is the first report of an unfunctionalized porphyrinoid that forms a well-defined complex with C60 in solution as well as in solid state.

Fullerene-Clad Ultra-Long Carbon Nanotubes

Fullerene-clad double-walled carbon nanotubes were synthesized by impregnation of the nanotubes with organic solution of fullerene C60 and consequent immobilization by laser irradiation. The resulting fullerene- nanotube composites were characterized by both electron microscopy and X-ray photoemission spectroscopy. The formation of densely packed layer of polymerized fullerene bonded to the nanotube surface was shown.

Formation of new hybrid structures: Fullerene C60–amphiphilic copolymer of N-vinylpyrrolidone with (di)methacrylates in isopropyl alcohol

New hybrid structures of fullerene C60 and an amphiphilic copolymer of N-vinylpyrrolidone with lauryl methacrylate and triethylene glycol dimethacrylate have been obtained via solubilization of fullerene by individual macromolecules and their micelle-like aggregates that form in isopropyl alcohol. The volume ratios of copolymer and C60 solutions in toluene at which there is suppression of aggregation of fullerene and fullerene–polymer particles and the existence of stable hybrid structures in solution have been found. With the use of absorption electron spectroscopy, it has been shown that, with time, fullerene undergoes binding to donor groups of the copolymer and forms a donor–acceptor complex. According to the data of optical microscopy, fullerene is homogeneously distributed as spherical aggregates in the solid polymer matrix.

Van-der-Waals based solvates of C60 with CBr2Cl2 and CBr2(CH3)2

We demonstrate that solvates of fullerene C60 form very predictable structures with finely tunable properties through the choice of the second component or solvent. Cubic co-crystals of C60·12CCl2Br2 and C60·12CBr2(CH3)2 were grown at room temperature in saturated solutions of fcc C60 and the respective solvents (with C2v molecular symmetry) They are unstable in air and transform spontaneously into the hexagonal co-crystals C60·2CCl2Br2 or C60·2CBr2(CH3)2. Whereas, the cubic co-crystals have positive excess volumes (+2% and +5%, respectively), the stable hexagonal crystals, for which structures are given for the first time, possess negative excess volumes (−5% and −4.3%, respectively). The unit-cell volumes for both cubic and hexagonal co-crystals depend exclusively on the van-der-Waals volumes of the constituents and this correlation has been confirmed using previously published data.

Hierarchically Structured Fullerene C70 Cube for Sensing Volatile Aromatic Solvent Vapors.

We report the preparation of hierarchically structured fullerene C70 cubes (HFC) composed of mesoporous C70 nanorods with crystalline pore walls. Highly crystalline cubic shape C70 crystals (FC) were grown at a liquid-liquid interface formed between tert-butyl alcohol and C70 solution in mesitylene. HFCs were then prepared by washing with isopropanol of the FC at 25 °C. The growth directions and diameters of C70 nanorods could be controlled by varying washing conditions. HFCs perform as an excellent sensing system for vapor-phase aromatic solvents due to their easy diffusion through the mesoporous architecture and strong π-π interactions with the sp(2) carbon-rich pore walls. Moreover, HFCs offer an enhanced electrochemically active surface area resulting in an energy storage capacity 1 order of magnitude greater than pristine C70 and fullerene C70 cubes not containing mesoporous nanorods.

Surfactant-Triggered Nanoarchitectonics of Fullerene C60 Crystals at a Liquid-Liquid Interface.

Here, we report the structural and morphological modulation of fullerene C60 crystals induced by nonionic surfactants diglycerol monolaurate (C12G2) and monomyristate (C14G2). C60 crystals synthesized at a liquid-liquid interface comprising isopropyl alcohol (IPA) and a saturated solution of C60 in ethylbenzene (EB) exhibited a one-dimensional (1D) morphology with well-defined faceted structure. Average length and diameter of the faceted rods were ca. 4.8 μm and 747 nm, respectively. Powder X-ray diffraction pattern (pXRD) confirmed a hexagonal-close packed (hcp) structure with cell dimensions ca. a = 2.394 nm and c = 1.388 nm. The 1D rod morphology of C60 crystals was transformed into "Konpeito candy-like" crystals (average diameter ca. 1.2 μm) when the C60 crystals were grown in the presence of C12G2 or C14G2 surfactant (1%) in EB. The pXRD spectra of "Konpeito-like" crystals could be assigned to the face-centered cubic (fcc) phase with cell dimensions ca. a = 1.4309 nm (for C12G2) and a = 1.4318 nm (for C14G2). However, clusters or aggregates of C60 lacking a uniform morphology were observed at lower surfactant concentrations (0.1%), although these crystals exhibited an fcc crystal structure. The self-assembled 1D faceted C60 crystals and "Konpeito-like" C60 crystals exhibited intense photoluminescence (PL) (∼35 times greater than pC60) and a blue-shifted PL intensity maximum (∼15 nm) compared to those of pC60, demonstrating the potential use of this method for the control of the optoelectronic properties of fullerene nanostructures. The "Konpeito-like" crystals were transformed into high surface area nanoporous carbon with a graphitic microstructure upon heat-treatment at 2000 °C. The heat-treated samples showed enhanced electrochemical supercapacitance performance (specific capacitance is ca. 175 F g-1, which is about 20 times greater than pC60) with long cyclic stability demonstrating the potential of the materials in supercapacitor device fabrication.

Protein-directed self-assembly of a fullerene crystal.

Learning to engineer self-assembly would enable the precise organization of molecules by design to create matter with tailored properties. Here we demonstrate that proteins can direct the self-assembly of buckminsterfullerene (C60) into ordered superstructures. A previously engineered tetrameric helical bundle binds C60 in solution, rendering it water soluble. Two tetramers associate with one C60, promoting further organization revealed in a 1.67-Å crystal structure. Fullerene groups occupy periodic lattice sites, sandwiched between two Tyr residues from adjacent tetramers. Strikingly, the assembly exhibits high charge conductance, whereas both the protein-alone crystal and amorphous C60 are electrically insulating. The affinity of C60 for its crystal-binding site is estimated to be in the nanomolar range, with lattices of known protein crystals geometrically compatible with incorporating the motif. Taken together, these findings suggest a new means of organizing fullerene molecules into a rich variety of lattices to generate new properties by design.

Features of self-aggregation of C60 molecules in toluene prepared by different methods

Structural and dimensional features of C60 aggregates in toluene solution prepared in two different ways – equilibrium and strongly non-equilibrium – were studied by high-resolution transmission electron microscopy and atomic-force microscopy methods. It was found that in solutions prepared by the non-equilibrium method (stirring of solution of C60 by a mechanical rotator), large quasispherical aggregates (with a diameter of up to ∼380±20 nm) of nanoporous structure with fractal size D≈2.13 were synthesized. In the case of solutions C60, which were prepared by the equilibrium method (without the use of external mechanical influences on solution), the formation of densely packed monomolecular fullerene aggregates with a diameter of not more than 50 nm was observed.

(Invited) Synthesis of Nitrogen-Embedded Buckybowl and Its Strong Association Behavior with C60

Curved π-conjugated molecules have attracted considerable interest because of their unique properties originating from their curved π surface. Besides their figurative beauty, the curved psurface generates unique functions such as chiroptical properties, anisotropic electron transitions, and dynamic motion in solution and solid states. However, the synthesis of such distorted molecules requires harsh conditions, which hamper an easy access to heteroatom-containing curved π-systems. Buckybowls represent important curved π-conjugated molecules, which can be precursors for the bottom-up synthesis of fullerenes and nanotubes. The nitrogen-embedded bowl-shaped molecules have been sought as model compounds for azafullerenes and nitrogen-doped carbon nanotubes. However, the synthesis of buckybowls with internal nitrogen atoms has been still challenging. Here we report the synthesis of a π-extended azacorannulene with nitrogen in its center. The oxidation of 9-aminophenanthrene provides tetrabenzocarbazole, which is converted to the azabuckybowl through palladium-catalyzed intramolecular coupling reaction. The structure was unambiguously elucidated by X-ray diffraction analysis, showing its bowl-shaped conformation. The electron-donating nature and curved π surface of the azabuckybowl enable its tight association with C60 in solution and solid states. The titration experiments with C60 by electronic absorption and emission spectroscopic analysis indicate the presence of intermolecular charge-transfer interaction between them. In addition, high charge carrier mobility was observed for the azabuckybowl/C60 assembly in solid state. This new compound would be a novel molecular entity in the field of curved π systems as fullerene hosts, anisotropic π donors, and precursors to nitrogen-containing nanocarbon materials. Figure 1

Anti-inflammatory effect of fullerene C60 in a mice model of atopic dermatitis.

Background Water-soluble form of fullerene C60 is a promising tool for the control of ROS-dependent inflammation including allergic diseases. Anti-inflammatory effects of C60 (nC60) aqueous dispersion were evaluated in the mouse models of atopic dermatitis using subcutaneous (SC) and epicutaneous (EC) applications during 50 days period. A highly stable nC60 was prepared by exhaustive dialysis of water-organic C60 solution against water, where the size and ζ-potential of fullerene nanoparticles are about 100 nm and −30 mV, respectively.ResultsTo induce skin inflammation, female BALB/c mice were EC sensitized with ovalbumin three times during one-weekly exposures. The nC60 solution was administrated in mice subcutaneously (SC) (0.1 mg/kg) and epicutaneously (EC) (1 mg/kg). Significant suppression of IgE and Th2 cytokines production and a concomitant rise in concentrations of Th1 cytokines were observed in nC60-treated groups. In addition, a significant increase in the levels of Foxp3+ and filaggrin mRNA expression was observed at EC application. Histological examination of skin samples indicated that therapeutic effect was achieved by both EC and SC treatment, but it was more effective with EC. Pronounced reduction of the eosinophil and leukocyte infiltration in treated skin samples was observed.ConclusionsWe suppose that nC60 treatment shifts immune response from Th2 to Th1 and restores to some extent the function of the skin barrier. This approach can be a good alternative to the treatment of allergic and other inflammatory diseases.

Efficient planar perovskite solar cells prepared via a low-pressure vapor-assisted solution process with fullerene/TiO2 as an electron collection bilayer

Cross-sectional SEM image and schematic J–V curves of the PSCs prepared with device architecture of the solar cells different C60 solution concentrations.