Optimization of the liquid–liquid interfacial precipitation method for the synthesis of $$\hbox {C}_{60}$$ C 60 nanotubes

Abstract

Tubular fullerene nanowhiskers called 'fullerene nanotubes' are composed of C 60 fullerene molecules (C 60 NTs) are synthesized at room temperature using the liquid-liquid interfacial precipitation method in the pyridine and isopropyl alcohol (IPA) system. The growth control of fullerene nanotubes is important for their chemical and physical properties as well as for their future applications. In the present study, we investigated the effect of light, water, solvent ratio and temperature on the synthesis of C 60 nanotubes. A marked development in the yield of C 60 NTs was achieved using dehydrated solvents, a solution with a volume ratio of 1:9 for pyridine: IPA, a growth temperature equal to 5 • C and by illuminating the C 60-pyridine solution with ultraviolet light (wavelength 302 nm) for 102 h. The synthesized fullerene nanotubes were characterized by different analytical techniques including Raman and Fourier transform infrared spectroscopy, optical microscopy, focussed ion beam scanning electron microscopy and transmission electron microscopy.

Ambipolar to Unipolar Conversion in C70/Ferrocene Nanosheet Field-Effect Transistors

“…Recent findings by Liu et al demonstrate the effectiveness of micro/nanoscale interface passivation combined with flexible polymer dielectrics in enhancing the electrical performance of OFETs [44]; this may be an effective approach for the optimization of devices based on C70/Fc nanosheets. The ambipolar characteristics observed in the C70/Fc nanosheets were also found in the C60/Fc nanosheets [34]. However, this result is in stark contrast to our previous findings, in which C70 nanosheet-based FETs displayed n-type behavior only [45].…”

“…Subtracting the standardized absorption spectrum of the C70 powder from that of the C70/Fc cocrystals revealed an additional absorption in the 1000-700 nm range, with a peak absorption at 800 nm, which was identified as the CT absorption band of the C70/Fc nanosheets. The CT transition energy corresponding to the peak at 800 nm is estimated to be 1.55 eV, which is very close to that of the C60/Fc nanosheets reported by our group [34]. Interestingly, upon heating, the 800 nm band gradually disappeared, confirming its nature as a CT band.…”

“…In our previous study [39], we observed irreversible switching in the semiconducting characteristics of the device, i.e., the transition from ambipolar to unipolar, which matched the thermally induced structural transition of the C60/Fc nanosheets. Additionally, Osonoe The ambipolar characteristics observed in the C 70 /Fc nanosheets were also found in the C 60 /Fc nanosheets [34]. However, this result is in stark contrast to our previous findings, in which C 70 nanosheet-based FETs displayed n-type behavior only [45].…”

“…Hence, fabricating organic cocrystals provides a feasible means of obtaining ambipolar materials; nevertheless, the preparation of these semiconductors remains a challenge owing to complex organic syntheses. However, using a simple and efficient liquid-liquid interfacial precipitation method for the synthesis of low-dimensional nanomaterials based on fullerenes [33][34][35][36][37], our group has successfully synthesized cocrystals of fullerenes with ambipolar transport characteristics [1,38,39]. Recently, we successfully demonstrated the capability to irreversibly switch the electrical properties of C 60 /Fc nanosheets from ambipolar to unipolar by thermal stimulation [39].…”

Ambipolar to unipolar irreversible switching in nanosheet transistors: the role of ferrocene in fullerene/ferrocene nanosheets

“…Previously, we have developed low-dimensional nanomaterials based on fullerenes, 12,13 such as fullerene nanowhiskers, [14][15][16][17] fullerene nanotubes, 18 and fullerene nanosheets, 19 using the liquid-liquid precipitation (LLIP) method. In 2009, we reported the preparation of triclinic C 60 /ferrocene (C 60 /Fc) D-A cocrystal nanosheets with a size of approximately 9 mm that contained C 60 (Fc) 2 units.…”