Analysis and Optimization of Stability for Graphene Nanoribbon-Carbon Nanotube Mixed Structure Interconnect in Integrated Circuit

We have been developing host-guest methodology for separation of single-walled carbon nanotubes (SWNTs) according to the handedness and diameter with gable-type chiral diporphyrins, designated as diporphyrin nanotweezers, consisting of two porphyrins and rigid spacer in between [1-4]. In this paper, we will talk about next generation of the host molecules focusing on larger diameter of SWNTs, named “nanocalipers” (Figure 1) [5,6].X. Peng, N. Komatsu,* S. Bhattacharya, T. Shimawaki, S. Aonuma, T. Kimura, A. Osuka, "Optically Active Single-Walled Carbon Nanotubes", Nature Nanotechnology, 2 (6), 361-365 (2007)G. Liu, F. Wang, X. Peng, A. F. M. M. Rahman, A. K. Bauri, and N. Komatsu, "Separation of Left- and Right-Handed Structures of Single-Walled Carbon Nanotubes through Molecular Recognition" Handbook of Biomedical Applications of Carbon Nanomaterials; K. M. Kadish and F. D'souza, Eds.; World Scientific: vol. 3, pp. 203-232 (2012).A. F. M. M. Rahman, F. Wang, K. Matsuda, T. Kimura, and N. Komatsu,* "Diameter-based separation of single-walled carbon nanotubes through selective extraction with dipyrene nanotweezers" Chem. Sci., 2 (5), 862-867 (2011) [highlighted at the inside front cover].F. Wang, K. Matsuda, A. F. M. M. Rahman, X. Peng, T. Kimura, and N. Komatsu,* "Simultaneous Discrimination of Handedness and Diameter of Single-Walled Carbon Nanotubes (SWNTs) with Chiral Diporphyrin Nanotweezers Leading to Enrichment of Single Enantiomer of (6,5)-SWNTs", J. Am. Chem. Soc., 132 (31), 10876-10881 (2010).G. Liu, A. F. M. M. Rahman, S. Chaunchaiyakul, T. Kimura, Y. Kuwahara, N. Komatsu,* "Bis(tert-butylpyrene) Nanotweezers and Nanocalipers: Enhanced Extraction and Recognition Abilities for Single-Walled Carbon Nanotubes", Chem. Eur. J., published online (DOI: 10.1002/chem.201302799).G. Liu, F. Wang, S. Chunchaiyakul, Y. Saito, A. K. Bauri, T. Kimura, Y. Kuwahara, N. Komatsu,* "Simultaneous Discrimination of Diameter, Handedness, and Metallicity of Single-Walled Carbon Nanotubes with Chiral Diporphyrin Nanocalipers", J. Am. Chem. Soc., 135 (12), 4805-4814 (2013) [highlighted in Chemical & Engineering News, 91 (12), p. 34, March 25, 2013].

Forecasting carbon nanotube diameter in floating catalyst chemical vapor deposition

In this paper, the optimum diameter of stable single-walled carbon nanotubes (SWNT's) in a rope is calculated theoretically using its conformation energy, which consists of curvature elastic energy and intertube van der Waals energy. An equlibrium shape equation for single layer fullerenes is derived by means of variation of the conformation energy. For straight SWNT's in an SWNT rope, the solution to the equlibrium shape equation gives the optimum diameter to be $1.36\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ for stable SWNT's. This agrees well with the experimental observation [Nature 388, 756 (1997); Science 273, 483 (1998)].

Spontaneous and controlled-diameter synthesis of single-walled and few-walled carbon nanotubes

In this paper, we compare the nonlinear optical properties and suitability of small (∼0.8 nm) and large diameter (∼1.4 nm) single wall carbon nanotubes (SWCNT) for fiber laser mode-locking near the technologically important 1 μm wavelength. We measured the nonlinear modulation depth ant saturation fluence in 1030–1070 nm wavelength interval, which is close to the first excitonic transition (E11) of small diameter SWCNTs. We verify, that small diameter SWCNTs are beneficial for fiber laser mode-locking at the 1064 nm wavelength as they have much lower saturation fluence (F sat, 11 = 8 μJ/cm2) than larger diameter SWCNTs — (F sat,22 = 329 μJ/cm2) working at E22 transition. The bulk absorption of small diameter (∼0.8 nm) nanotubes consists of superposition of absorption narrow optical absorption lines of SWCNTs with different chirality

We have been developing the methodology to discriminate the handedness and diameter of single-walled carbon nanotubes (SWNTs) through molecular recognition using chiral diporphyrin nanotweezers. Although relatively small diameters of SWNTs (<1.0 nm) were recognized well, nanotweezers were not able to form stable complexes with the SWNTs having the diameters >1.0 nm. In this context, we designed chiral diporphyrin with a much larger cavity, namely, "nanocalipers". The feature of the newly designed host molecule is: (1) long spacer with more than 1.4 nm consisting of three aromatic moieties; (2) nearly parallel orientation of the two porphyrins; (3) restricted conformation by biaryl linkages of the porphyrin-carbazole and carbazole-anthracene; (4) strong interaction of two porphyrins and anthracene with the surface of a SWNT through π-π stacking; and (5) stereogenic centers at the periphery of porphyrins discriminating helicity of SWNTs. As expected, we obtained optically active SWNTs with >1.0 nm in diameter and, unexpectedly, enriched metallic SWNTs over semiconducting ones. The optically active metallic SWNTs are identified for the first time, in addition to the optically active semiconducting SWNTs with such large diameters. The nanocalipers are found to recognize the diameter, handedness, and metallicity of SWNTs simultaneously.

We reviewed and examined recent progresses related to the nanochemistry and nanobiology of signal-walled carbon nanotubes (SWCNTs), focusing on the diameters of SWCNTs and how the diameters affect the interactions of SWCNT with protein and DNA, which underlay more complex biological responses. The diameters of SWCNTs are closely related to the electronic structure and surface chemistry of SWCNTs, and subsequently affect the interaction of SWCNTs with membrane, protein, and DNA. The surfaces of SWCNT with smaller diameters are more polar, and these with large diameters are more hydrophobic. The preference of SWCNT to interact with Trp/Phe/Met residues indicates it is possible that SWCNT may interfere with normal protein-protein interactions. SWCNT-DNA interactions often change DNA conformation. Besides the promising future of using SWCNTs as delivering nanomaterial, thermal therapy, and other biological applications, we should thoroughly examine the possible effects of carbon nanotube on interrupting normal protein-protein interaction network and other genetic effects at the cellular level.

The hollow core and well-defined diameters of single-walled carbon nanotubes (SWCNTs) allow for creation of unique one-dimensional hybrid structures by encapsulation of various molecules. For instance, we previously demonstrated that in this way dipolar dye molecules can be naturally aligned in an ideal head-to-tail arrangement to create assemblies with a giant total nonlinear optical response.[1] Here, we show that the optical properties of dye molecules encapsulated in SWCNTs can be strongly modulated by the SWCNT diameter, indicating very specific diameter-dependent stacking and interactions of the molecules. The filling is thoroughly characterized by optical absorption, resonant Raman, and two-dimensional infrared photoluminescence excitation (PLE) spectroscopy. Energy transfer probed by PLE spectroscopy shows the absorption spectrum of the dyes to be strongly diameter-dependent, and transient absorption spectroscopy, simultaneously probing the encapsulated dyes and the host SWCNTs, demonstrates sub-picosecond EET from encapsulated molecules to the host SWCNTs. The design of these functional hybrid systems, with tuneable dye absorption, EET depending on the SWCNT diameter and the ability to remove all metallic SWCNTs by subsequent separation, demonstrates potential for implementation in dedicated photo-conversion devices. [1] S. Cambré, J. Campo et al., Nature Nanotechnol. 10, 248 (2015).

To have uniform nanoparticles individually dispersed on substrate before single-walled carbon nanotubes (SWNTs) growth at high temperature is the key for controlling the diameter of the SWNTs. In this letter, a facile approach to control the diameter and distribution of the SWNTs by improving the dispersion of the uniform Fe/Mo nanoparticles on silicon wafers with silica layer chemically modified by 1,1,1,3,3,3-hexamethyldisilazane under different conditions is reported. It is found that the dispersion of the catalyst nanoparticles on Si wafer surface can be improved greatly from hydrophilic to hydrophobic, and the diameter and distribution of the SWNTs depend strongly on the dispersion of the catalyst on the substrate surface. Well dispersion of the catalyst results in relatively smaller diameter and narrower distribution of the SWNTs due to the decrease of aggregation and enhancement of dispersion of the catalyst nanoparticles before growth. It is also found that the diameter of the superlong aligned SWNTs is smaller with more narrow distribution than that of random nanotubes.

With a vertical resolution of 0.1 nm, atomic force microscopy (AFM) height measurements can be used to determine accurately the diameter of single-walled carbon nanotubes (SWNT) with the assumption that they have circular cross sections. The aim of this article is to draw attention to the need to optimize operating parameters in tapping mode for quantitative AFM height (diameter) analysis of SWNTs. Using silicon tip/cantilever assemblies with force constants ranging from 0.9 to 40 N m(-1), we examined the effect of applied force on the apparent diameter of SWNT wrapped with a 29-residue amphiphilic alpha-helical peptide. A decrease in apparent height (SWNT diameter) with increasing applied force was observed for the higher force constant cantilevers. Cantilevers having force constants of 0.9 and 3 N m(-1) demonstrated minimal vertical sample compression with increasing applied force. The effects of AFM image pixel density and scan speed on the measured height (diameter) of SWNTs were also assessed.

Chlorinated paraffins wrapping of carbon nanotubes: A theoretical investigation

Growth of single and double walled carbon nanotubes over Co/V/MgO catalysts

The potentiality of optical absorption spectroscopy (OAS) for the estimation of mean diameter of single-wall carbon nanotubes (SWCNTs) from electronic transition energies has been explored. The observed dependence of electronic transition energies of both metallic and semiconducting SWCNTs on their mean diameters clearly showed that transition energies scale inversely with the tube diameter. In the present study, the applicability of this estimation method has been experimentally confirmed for the diameter range of 1–2 nm and is expected to be useful for the characterization of wide range of diameters of SWNCTs.

In the present study, we systematically described the tuning of the diameter of single-walled carbon nanotubes (SWNTs) from individual catalyst particle by temperature-mediated chemical vapor depos...

The diameters of single-walled carbon nanotubes (SWCNTs) are directly related to their electronic properties, making diameter control highly desirable for a number of applications. Here we utilized a machine learning planner based on the Expected Improvement decision policy that mapped regions where growth was feasible vs. not feasible and further optimized synthesis conditions to selectively grow SWCNTs within a narrow diameter range. We maximized two ranges corresponding to Raman radial breathing mode frequencies around 265 and 225 cm−1 (SWCNT diameters around 0.92 and 1.06 nm, respectively), and our planner found optimal synthesis conditions within a hundred experiments. Extensive post-growth characterization showed high selectivity in the optimized growth experiments compared to the unoptimized growth experiments. Remarkably, our planner revealed significantly different synthesis conditions for maximizing the two diameter ranges in spite of their relative closeness. Our study shows the promise for machine learning-driven diameter optimization and paves the way towards chirality-controlled SWCNT growth.