Bandgap modulation of carbon nanotubes by encapsulated metallofullerenes

Lee, Jhinhwan; Kim, H.; Kahng, Se-Jong; Kim, Geehyun; Son, Young‐Woo; Ihm, Jisoon; Kato, H.; Wang, Z. W.; Okazaki, Toshiya; Shinohara, Hisanori; Kuk, Young

doi:10.1038/4151005a

Cited by 468 publications

(433 citation statements)

References 20 publications

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“…41 Lee et al observed a modified electronic structure of the nanotube in CNT-encapsulated Gd metallofullerenes, as evidenced by low-temperature scanning tunneling microscopy. 42 The above results demonstrate that an electronic interaction exists between metal species and the CNT surfaces and the strength can vary with metals and with the size of CNTs. The modified electronic structure of metal/metal oxide nanoparticles induced by confinement can influence their catalytic activity as redox reactions involve electron transfer between reactants and catalysts.…”

Section: Toward Understanding the Confinement Effects In Catalysismentioning

confidence: 71%

The Effects of Confinement inside Carbon Nanotubes on Catalysis

2011

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T he unique tubular morphology of carbon nanotubes (CNTs) has triggered wide research interest. These structures can be used as nanoreactors and to create novel composites through the encapsulation of guest materials in their well-defined channels. The rigid nanotubes restrict the size of the encapsulated materials down to the nanometer and even the subnanometer scale. In addition, interactions may develop between the encapsulated molecules and nanomaterials and the CNT surfaces. The curvature of CNT walls causes the π electron density of the graphene layers to shift from the concave inner to the convex outer surface, which results in an electric potential difference. As a result, the molecules and nanomaterials on the exterior walls of CNTs likely display different properties and chemical reactivities from those confined within CNTs. Catalysis that utilizes the interior surface of CNTs was only explored recently. An increasing number of studies have demonstrated that confining metal or metal oxide nanoparticles inside CNTs often leads to a different catalytic activity with respect to the same metals deposited on the CNT exterior surface. Furthermore, this inside and outside activity difference varies based on the metals used and the reactions catalyzed.In this Account, we describe the efforts toward understanding the fundamental effects of confining metal nanoparticles inside the CNT channels. This research may provide a novel approach to modulate their catalytic performance and promote rational design of catalysts. To achieve this, we have developed strategies for homogeneous dispersion of nanoparticles inside nanotubes. Because researchers have previously demonstrated the insertion of nanoparticles within larger nanotubes, we focused specifically on multiwalled carbon nanotubes (MWCNTs) with an inner diameter (i.d.) smaller than 10 nm and double-walled carbon nanotubes (DWCNTs) with 1.0À1.5 nm i.d. The results show that CNTs with well-defined morphology and unique electronic structure of CNTs provide an intriguing confinement environment for catalysis.

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Section: Toward Understanding the Confinement Effects In Catalysismentioning

confidence: 71%

The Effects of Confinement inside Carbon Nanotubes on Catalysis

2011

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“…Nanotubes can be side-gated with selfaligned, regularly spaced metal electrodes tens of nanometers wide [51]. Fullerenes in a SWNT locally alter the electronic states of the SWNT [52,53]. If the electronic states of the nanotube and fullerene are coupled, then this offers a mechanism for qubits to interact over distance through the nanotube.…”

Section: "Peapod" Nanotubesmentioning

confidence: 99%

Towards a fullerene-based quantum computer

Benjamin

Ardavan

Briggs

et al. 2006

J. Phys.: Condens. Matter

177

141

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Abstract. Molecular structures appear to be natural candidates for a quantum technology: individual atoms can support quantum superpositions for long periods, and such atoms can in principle be embedded in a permanent molecular scaffolding to form an array. This would be true nanotechnology, with dimensions of order of a nanometre. However, the challenges of realising such a vision are immense. One must identify a suitable elementary unit and demonstrate its merits for qubit storage and manipulation, including input / output. These units must then be formed into large arrays corresponding to an functional quantum architecture, including a mechanism for gate operations. Here we report our efforts, both experimental and theoretical, to create such a technology based on endohedral fullerenes or 'buckyballs'. We describe our successes with respect to these criteria, along with the obstacles we are currently facing and the questions that remain to be addressed.

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“…Its spatial resolution, however, is generally limited by wavelength, and information is inevitably averaged over the nanoscale components, despite that they are organized with the greatest care to produce desired functions. In contrast, the real space observation of atomic-scale structures by scanning tunneling microscopy (STM) has lifted the veil from various longstanding problems and is extending the frontiers of science and technology [4][5][6][7][8][9]. However, since the temporal resolution of STM is limited to less than 100 kHz because of the circuit bandwidth, the target carrier dynamics has been beyond its field of vision.…”

mentioning

confidence: 99%