Study on structure of heat‐treated fullerene nanowhiskers and their field electron emission characteristics

Asaka, Kinji; Nakayama, Tadachika; Miyazawa, Kun’ichi; Saito, Yahachi

doi:10.1002/sia.3868

Cited by 7 publications

(4 citation statements)

References 19 publications

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“…The simulated C 60 fibers, the molecular stacking structures, and an hcp unit cell of the crystal are depicted in Figure d–f. Figure b shows the XRD traces of the freshly obtained C 60 fibers and those after treatment in vacuum at different temperatures for 4 h . It is observed that heating treatment makes the packing nature of fibers turned from hcp to fcc , gradually.…”

Section: Methodsmentioning

confidence: 99%

Spatially Confined Growth of Fullerene to Super‐Long Crystalline Fibers in Supramolecular Gels for High‐Performance Photodetector

et al. 2019

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been developed to grow 1D C 60 crystals including template method, slow evaporation, precipitation, liquid/liquid interface precipitation (LLIP), volatile diffusion, and gel-assisted method in general. While early attempts to grow C 60 crystals resulted in various morphologies, it was the use of crystalline C 60 fibers that had attracted particular interest because of their outstanding properties with high surface area and low dimensionality. [14] Although some methods were used to grow 1D fullerene crystals, it is still a great challenge to grow them with tunable sizes owing to their naturally 0D structures. Thus, to develop a method for the controlled growth of 1D C 60 crystals is still challenging and demanding for its promising applications, e.g., photodetector.As a recently developed medium for crystal growth, supramolecular gels derived from low-molecular-mass gelators (LMMGs), are a typical class of soft materials in which gelator molecules can be assembled into dynamic 3D networks via cooperative noncovalent interactions. [15][16][17][18][19][20][21][22] The gel matrix commonly entraps solvent molecules and prevents the macroscopic flow of the solvent within its networks. Sedimentation or aggregation of the crystals is suppressed in supramolecular gels and the arbitrary growths along faces in contact with the vessel walls or other crystals are also limited. Furthermore, the supramolecular gel could act as an inert matrix repressing heterogenous nucleation and making homogenous nucleation dominant. Or it affords an activated gel As a superstar organic semiconductor, fullerene (C 60 ) is versatile in nature for its multiple photoelectric applications. However, owing to its natural 0D structure, a challenge still remains unbeaten as to growth of 1D fullerene crystals with tunable sizes. Herein, reported is an efficient approach to grow C 60 as super-long crystalline fibers with tunable lengths and diameters in supramolecular gel by synergic changes of anti-solvent, gel length, crystallization time or fullerene concentration. As a result, the crystalline C 60 fibers can be modulated to as long as 70 mm and 70 000 in their length-to-width ratio. In this case, the gel 3D network provides spatial confinements for the growth of 1D crystal along the directional dispersion of anti-solvent. The fabricated fullerene device exhibits high responsivity (2595.6 mA W -1 ) and high specific detectivity (2.7 × 10 12 Jones) at 10 V bias upon irradiation of 400 nm incident light. The on/off ratio and its quantum efficiency are near to 540 and about 800%, respectively, and importantly, its photoelectric property remains very stable after storage in air for six months. Therefore, spatially confined growth of fullerene in supramolecular gels will be another crucial strategy to synthesize 1D semiconductor crystals for photoelectrical device applications in near future. 1D Fullerene CrystallizationAs a typical 0D carbon-based material, fullerene (C 60 ) is one of the important organic semiconductors and is versatile in nature on a...

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Section: Methodsmentioning

confidence: 99%

Spatially Confined Growth of Fullerene to Super‐Long Crystalline Fibers in Supramolecular Gels for High‐Performance Photodetector

et al. 2019

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“…Those C 60 NWs heated at high temperatures with developed graphitic ribbons are promising materials that may exhibit superconductivity if doped with alkali metals and alkaline-earth metals. In addition, the high-temperature-treated C 60 NWs become electron emission tips showing striped patterns that reflect the atomic structure of the crumpled graphitic layers [ 78 , 79 ]. However, since long amorphous carbon nanofibers prepared by high-temperature heat treatment of C 60 NWs showed cytotoxicity like long multiwall carbon nanotubes [ 96 ], special care will be necessary in the practical uses of the glassy carbon nanofibers.…”

Section: Electrical and Superconducting Properties Of C 60 mentioning

confidence: 99%

Synthesis of fullerene nanowhiskers using the liquid–liquid interfacial precipitation method and their mechanical, electrical and superconducting properties

Miyazawa

2015

Science and Technology of Advanced Materials

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Fullerene nanowhiskers (FNWs) are thin crystalline fibers composed of fullerene molecules, including C60, C70, endohedral, or functionalized fullerenes. FNWs display n-type semiconducting behavior and are used in a diverse range of applications, including field-effect transistors, solar cells, chemical sensors, and photocatalysts. Alkali metal-doped C60 (fullerene) nanowhiskers (C60NWs) exhibit superconducting behavior. Potassium-doped C60NWs have realized the highest superconducting volume fraction of the alkali metal-doped C60 crystals and display a high critical current density (Jc) under a high magnetic field of 50 kOe. The growth control of FNWs is important for their success in practical applications. This paper reviews recent FNWs research focusing on their mechanical, electrical and superconducting properties and growth mechanisms in the liquid–liquid interfacial precipitation method.

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“…Reference source not found., the electrical properties of C 60 NWs vary from insulator to semiconductor depending on diameter. In addition, C 60 NWs become conductive glass-like carbon nanofibers following high-temperature heat treatment in an inert atmosphere [22]. Additionally, C 60 NWs can be made into superconductors by doping with alkali metals such as potassium [23] [24].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and structural analysis of C60–C70 two-component fullerene nanowhiskers

Konno

Wakahara

Miyazawa

2015

Journal of Crystal Growth

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C 60-C 70 two-component fullerene nanowhiskers (C 60-C 70 NWs) were synthesized by liquid-liquid interfacial precipitation (LLIP) using various ratios of C 70 to C 60 and then analyzed using a focused ion beam processing apparatus (FIB-SEM), scanning electron microscopy (SEM), Raman spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD) and high-performance liquid chromatography (HPLC). Both C 60 and C 70 were saturated in the supernatant solutions with fullerene compositions in the mother solutions ranging from 12.4 mass% C 70 to 73.4 mass% C 70. C 60-C 70 NWs contained a small amount of rhombohedral phase, indicating polymerization of C 60. The solid solubility limit of C 70 in the C 60 matrix was found to be 13.7 mass%. In addition to fine C 60-C 70 NWs, thick C 60-C 70 needle-like crystals were formed. The thick C 60-C 70 needle-like crystals were fractured using a molybdenum probe in the FIB. The fractured surfaces of the C 60-C 70 needle-like crystals showed modulated structures with chemical compositions characteristic of spinodal decomposition. The activation energy of diffusion was determined to be 37.1 kJ /mol.

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Study on structure of heat‐treated fullerene nanowhiskers and their field electron emission characteristics

Cited by 7 publications

References 19 publications

Spatially Confined Growth of Fullerene to Super‐Long Crystalline Fibers in Supramolecular Gels for High‐Performance Photodetector

Spatially Confined Growth of Fullerene to Super‐Long Crystalline Fibers in Supramolecular Gels for High‐Performance Photodetector

Synthesis of fullerene nanowhiskers using the liquid–liquid interfacial precipitation method and their mechanical, electrical and superconducting properties

Synthesis and structural analysis of C60–C70 two-component fullerene nanowhiskers

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