Light-induced instability of PbO-filled single-wall carbon nanotubes

Abstract

We investigated single-wall carbon nanotubes filled with lead oxide, PbO, by transmission electron microscopy and Raman spectroscopy. It is concluded that PbO crystallizes in the orthorombic phase forming nanowires inside the nanotubes. The positions of the PbO Raman lines are downshifted as compared to the bulk material as a result of the reduced dimensionality. As a consequence of the filling, nanotubes become sensitive to the laser irradiation. At higher laser power densities, they oxidize and the free PbO nanowires are left in the sample.

Comparative analysis of electronic properties of tin, gallium, and bismuth chalcogenide-filled single-walled carbon nanotubes

“…Despite the fact that more than 150 different substances were encapsulated inside the SWCNTs [2], such as metal halogenides [14][15][16][17][18], organic and organometallic molecules [19][20][21][22], metals [23][24][25][26][27] and others [28][29][30], there are a very small number of reports on the filling of nanotubes with metal chalcogenides. The examples are HgTe [31,32], SnSe [33], SnTe [34], MoS 2 [35], GaSe [36,37], MnTe 2 [38].…”

Filled Carbon Nanotubes: (X@CNTs)

“…Likewise, condensation of Se was found to occur first in the narrowest nanotubes [66] and filling with Bi via the gas and liquid routes was found to be more efficient in SWCNTs than in MWCNTs 'as a result from stronger capillary forces' [11]. Generally speaking, SWCNT filling rates as high as ~70% (PbI 2 [28] and KI [82]) or even 80-90% (for PbO [84]) were observed and we can therefore conclude that nanowetting is a reality.…”

“…The procedure is similar to that for the solution method of the gas phase route, that is putting together the previously opened (or not, see next paragraph) nanotubes and the material to fill the latter within a quartz vessel sealed under vacuum, and then heating up the whole. The temperature has of course to be above (~30-100°C higher) the melting temperature of the filling material and maintained for long times, in the range of 1-3 days (see [82][83][84], among others) although this may be shorter for some low viscosity materials. Such long times are necessary to account for the high viscosity that the molten materials may exhibit and that slows down the filling kinetics (specifically within SWCNTs), and also to account for cycling (Figure 5a.7(c)).…”

“…The following list mostly corresponds to the materials inserted in SWCNTs (or DWCNTs) as reported by this group in the references provided (including review papers [37,[123][124][125]), and includes an increasing number of materials inserted by other groups also. The list is likely incomplete, but provides an idea of the extensive work carried out in the field: HgTe [27], MnTe2 [126], (Na/Tl/Cs/Ag)Cl [37,125,127] [135,136] and then followed by others such as PbO [84], Re x O y [67], and UO 2 [137] (although the latter was obtained from the primary filling of uranyl acetate) and hydroxides (KOH and CsOH [137]), sometimes with a fairly high filling rate (e.g. 80-90% for PbO).…”

Raman scattering from nanomaterials encapsulated into single wall carbon nanotubes

“…Thus the tubes are a well-designed template for the growth of a variety of other nanomaterials. Best known examples are the filling of the tubes with fullerenes, 1 and also inorganic materials such as alkali halides, 2 PbO, 3 HgTe, 4 FeCl 2 2 or biological materials such asˇ-carotene 5 or ice. 6 All these filler compounds exhibit automatically nanodimensions in two directions and are thus candidates for quantum-size effects.…”