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

Abstract

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.

Analysis of the Size of Two-Component C₆₀-C₇₀ Fullerene Whiskers

“…Vs of C70 increased at 13.7 wt% C70 which is the solid solubility limit of C70 in the matrix phase of C60 because C70 was able to precipitate at surfaces of most crystals. By the same token, Vs of C60 increased at 73.4 wt% C70 (26.6 wt% C60) which is the solid solubility limit of C60 in the matrix phase of C70 [8,24]. Thus, R of C70 have the maximal value at 13.7 wt% C70 and R of C60 exhibit the maximal value at 73.4 wt% C70.…”

“…FNWs can be applied to bulk-hetero-junction type electrode materials and quantum-dot type electrode materials as thin, long and efficient n-type semiconductors or light and flexible superconducting wire rods by alkalimetal doping [5,6]. Fullerene whiskers composed of C60 and C70 (C60-C70 fullerene whiskers) are characterized by the structure analysis and composition analysis using a focused ion beam processing apparatus (FIB-SEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), high-performance liquid chromatography (HPLC), Raman spectroscopy and ultraviolet-visible (UV-vis) spectroscopy, and found to be useful semiconductor materials with the composite effects of high Young's moduli, large specific strength, small amount of rhombohedral phase, the solid solubility limit of 14 mass% C70 or 27 mass% C60, and optical properties of both C60 and C70 [7,8]. They can be applied to various products such as the active layer materials of solar cells featuring the optical properties of both C60 and C70 and the anchor materials featuring the large specific strength and the high Young's moduli.…”

Fullerene (C60) Nanowires: The Preparation, Characterization, and Potential Applications

“…The solid solubility limit of C 70 in the matrix of C 60 was estimated to be 13.7 mass%. [45] Takeya et al have prepared superconducting potassium (K)-doped C 60 nanowires by the absorption of potassium to C 60 nanowires obtained by the LLIP method. C 60 nanowires with overall diameters of 540 nm and lengths of 4.43 lm were filtrated and dried up in air.…”

“…Konno et al [45] synthesized the two-component C 60 -C 70 fullerene nanowires by the LLIP method using various ratios of C 70 to C 60 . XRD patterns of both C 60 nanowires and C 60 -C 70 nanowires (the latter was made by using a solution of C 60 and C 70 with a concentration of 24 mass% C 70 ) are shown in Figure 12.…”

A dramatic improvement in the tensile strength of fullerene needle-like crystals

“…Since substitutional solid solutions can be formed from two species of atoms or molecules which are close in size, we use C60 and C70 molecules in order to obtain a solid solution in this study. C60-C70 needle-like crystals consisting of a C60 mother phase doped with 11 wt% C70 molecules have been analyzed to exhibit the light absorption band of both C60 and C70 and a Young's modulus of 60-100 GPa even when the crystal diameter exceeds 1000 nm [22,23] . Although the C60-C70 needle-like crystals are expected to be useful with low density, a high Young's modulus, a wide absorption band, and various electrical conductivities, the mechanical properties of such crystals have not yet been clarified.…”