• Journal of Sensor Science and Technology
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• v.13 no.5
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• pp.392-398
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• 2004

It is known that the conductivity of fullerite depends on the applied pressure. In this paper we compare the variation of conductivity of three different fullerite structure with pressure. We examined $C_{60}$ powder, filled into thin glass capillaries and also studied fullerite nanotubules produced within etched swift heavy ion tracks in polymer foils. These investigations are compared with the results of planar Si-$C_{60}$-Au structures.

• Journal of the Korean institute of surface engineering
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• v.37 no.2
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• pp.71-75
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• 2004

The technology of $C_{60}$ fullerite films preparation by means of gas-phase deposition and structure of fullerite films are described. A three-channel flow plant was used to obtain fullerite films. The films were deposited in the flow of inert gas under reduced pressure onto a cooled silicon or sapphire substrate placed inside the reaction chamber of the plant. The plant allows one to obtain the films of pure fullerenes and to synthesise the films from fullerene compounds and doped fullerenes. The structure of two types of films were investigated by FE-SEM and SEM techniques: pure fullerite films onto silicon and sapphire substrates as well as compound films were studied by FE-SEM technique. All samples have shown columnar structure with high level of porosity. The synthesis of films composed of fullerene and its compounds for use in electronics is demonstrated to be promising. For example, experiments confirm the possibility to use fullerite films in sensor electronics to produce humidity and thermal sensors. It is also possible to use the sensitivity of these films to isotropic pressure. The experiments with $C_{60}$-Cu-J films have shown quite strong dependence of their resistance on pressure of different sort of medium-gas that could be used in gas-sensitive sensors. The structure and preparation technology of resistive sensor based on fullerite films are described.bed.

• Journal of Sensor Science and Technology
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• v.13 no.5
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• pp.399-404
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• 2004

We report on the technology of formation of sandwich structures based on fullerite films and on experimental results in research of optical and conductivity properties of these sandwich samples. Single crystals of sapphire (100) or silicon were used as substrates. The sandwich specimens were based on the structure M/$C_{60}$/M (M=Cr, Pd, Ag, Al, Cu). The thickness of the fullerite films was about $0.2{\sim}1.0{\mu}m$. The area of the $C_{60}$ film under the top contact was about $1cm^{2}$. The specimens have been investigated by infrared spectroscopy, spectra-photometry, ellipsometry and X-ray diffraction analysis. Measurements of the current/voltage characteristics and research on the temperature dependence of conductivity were performed as well. It was shown that metals such as Cr, Pd, Ag, Al, and Cu penetrate easily into the fullerite films. It appears that these specimens have a large conductivity. For silver/$C_{60}$ and other sandwich structures the conductivities show a semiconductor-like behaviour.

• Journal of Sensor Science and Technology
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• v.13 no.4
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• pp.316-320
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• 2004

The possibility to use powder consisting of fullerite microcrystallines as a device sensitive to the external axial mechanical load is considered. We suppose that the change of conductivity of fullerite microcrystalline powder as a function of external mechanical stress will be useful for the creation of nanoscale devices of sensor electronics. This new effect based on changing of intermolecular distance between fullerene molecules due to the action of external mechanical force, which can change the distance between fullerene molecules because of weak van der Waals interaction exists. The founded effect is quite linear and sensitive to external mechanical stress is better then in well-known pressure transducers is based on silicon technology.

• Mass Spectrometry Letters
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• v.2 no.2
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• pp.49-52
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• 2011

Competitive binding of $C_{60}$ and $C_{70}$ to meso-substituted porphyrins was studied by mass spectrometry (MS). Electrospray ionization MS was employed to acquire the mass spectra of 1 : 1 porphyrin-fullerene complexes formed in a mixture of mesosubstituted porphyrin and fullerite to determine the ratio of complexes between $C_{60}$ and $C_{70}$. Matrix-free laser desorption ionization MS was used to obtain the mass spectra of fullerite to measure the mole fraction of $C_{60}$ and $C_{70}$. The binding constant ratio ($K_{70}$/$K_{60}$) was determined from the mass spectral data. The difference in standard Gibbs free energy change, ${\Delta}({\Delta}G^o)_{70-60}$, for the competitive binding of $C_{60}$ and $C_{70}$ was calculated from $K_{70}$/$K_{60}$. Of the five porphyrins, tetraphenyl, tetra(4-pyridyl), tetra(4-carboxyphenyl), tetra(3,5-di-tert-butylphenyl), and tetra(pentafluorophenyl) porphyrins, the first three non-bulky porphyrins yield negative values of ${\Delta}({\Delta}G^o)_{70-60}$, whereas the other two bulky porphyrins result in positive values of ${\Delta}({\Delta}G^o)_{70-60}$. This result indicates that $C_{70}$ binding to porphyrin is thermodynamically favored over $C_{60}$ binding in non-bulky porphyrins, but disfavored in bulky ones. It also suggests that the binding mode of $C_{70}$is different between non-bulky and bulky porphyrins, which is in line with previous experimental findings of the "side-on" binding to non-bulky porphyrins and the $C_{60}$-like "end-on" binding to bulky porphyrins.