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We filled SWNTs with the paramagnetic fullerene Sc@C82 to form peapods. The interfullerene 1D packing distance measured using TEM is d = 1.1 +/- 0.02 nm. The Sc@C82 in SWNT peapods continuously rotated during the 2 s TEM exposure time, and we did not see the Sc atoms. However, Sc@C82 metallofullerenes in MWNT peapods have periods of fixed orientation, indicated by the brief observation of Sc atoms. La@C82 peapods were also prepared and their rotational behavior examined. The interfullerene 1D packing of both La@C82 and Sc@C82 peapods is identical and thus independent of the charge transfer state for these paramagnetic fullerenes. The La@C82 metallofullerenes in the peapods have fixed orientations for extended periods of time, up to 50 s in some cases. The La@C82 spontaneously rotates rapidly between fixed orientations.

The rotation of fullerene chains in SWNT peapods is studied using low-voltage high resolution transmission electron microscopy. Anisotropic fullerene chain structures (i.e., C300) are formed in situ in carbon nanopeapods via electron beam induced coalescence of individual fullerenes (i.e., C60). A low electron accelerating voltage of 80 kV is used to prevent damage to the SWNT. The large asymmetric C300 fullerene structure exhibits translational motion inside the SWNT and unique corkscrew like rotation motion. Another asymmetric fullerene chain containing mixed fullerene species is prepared by fusing smaller C60 fullerenes to a larger Sc@C82 fullerene, and this also exhibits corkscrew rotational motion. Chains of Sc3C2@C80 in SWNT peapods adopt a zigzag packing structure, and the entire zigzag chain rotates inside the SWNT to induce structural modifications to the SWNT diameter and cross-sectional shape of the SWNT. The expansion and contraction of the diameter of the SWNT is measured as 17%, demonstrating nanoactuation behavior in carbon nanopeapods.

Ink-jet printable thin-film transistors (TFTs) on flexible plastic substrates are an important focus of research because present silicon-based electronics cannot realize such devices. In the present study, we fabricated single-walled carbon nanotube (SWCNT) TFTs on plastic substrates using the ink-jet printing method, and realized high-on/off current ratio (10 4 ) and flexibility, respectively. The present study therefore represents a major step towards ''flexible SWCNT electronics''.

Semiconducting networks were found to be extremely sensitive to charges, which promises the electrical detection of ultralow concentrations of DNA (down to 0.1 fM, ∼100 DNA molecules).

Single-walled carbon nanotube (SWCNT) thin-film transistors (TFTs) were fabricated using ink-jet printing. We printed both thick sourcedrain electrodes and thin active semiconducting films using N,N-dimethylformamide (DMF)-based SWCNT dispersion. Despite the presence of metallic SWCNTs, the device exhibited field-effect behavior, with an effective mobility of 2.99 cm 2 V À1 s À1 and an on/off current ratio of up to 75. The method used in this study is promising for the fabrication of large-scale high-performance SWCNT-TFTs.

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The magnetic properties of mono- and dierbium(Er) metallofullerenes have been studied by means of a synchrotron soft X-ray magnetic circular dichroism (SXMCD) technique. The effective magnetic moment of the Er ions has been estimated to be 8.48 μB and is independent of the number of Er ions encapsulated inside the fullerene cage. These Er metallofullerenes exhibit an antiferromagnetic-like behavior at low temperatures that is stronger in Er@C82(C 2 v isomer) monometallofullerene than in Er2@C82(C 2 v ) and Er2C2@C82(C 2 v ) dimetallofullerenes. The result suggests that the unpaired spin on the monometallofullerene cages causes an indirect magnetic interaction between Er 4f spins of neighboring metallofullerenes. Furthermore, we have found that the Weiss temperatures of the metallofullerene remain the same even when one of the Er ions in Er2C2@C82(C s ) is replaced by a nonmagnetic Y ion (i.e., ErYC2@C82). The results indicate that interaction between the two Er ions in the same fullerene cage does not contribute significantly to the overall magnetic properties.