bluuebunny/crossref_metadata_2025_split huggingface dataset:
Covalent Chemistry on Carbon Nanotubes: From Electronic Fundamentals to Sensor Applications
Authors: Bouilly Delphine , Martel Richard , Nuckolls Colin 
Published: February 2020

Carbon nanotube devices are particularly well-suited to build chemical or biological electronic nanosensors due to their inherent nanoscale channel, exceptional electrical conductance and high sensitivity to charge transfer. This charge sensitivity is mostly unselective though, which means that functionality must be added to the nanotube sidewall in order to tailor its affinity to specific chemical species. Single-point functionalization is particularly desirable to allow probing molecules at the individual level. Among the various functionalization types available for carbon nanotubes, covalent chemistry provides the most robustness and reproducibility. However, its invasive nature is known to alter the electronic performance of the nanotubes, and achieving single-point covalent binding on pristine nanotubes is challenging.
Here we present experimental work providing fundamental insight of the impact of covalent reactions on carbon nanotubes electronic properties, as well as recent advances on the use of covalently chemistry for assembling single-molecule nanosensors. First, electrical transport experiments are used to probe the electronic states of carbon nanotubes fully covered with covalent adducts. Results on numerous individual nanotube devices show that addition of monovalent groups such as aryl derivatives severely disrupt the nanotube electronic bands and also generate graft-induced localized states in the nanotube band gap [1]. Oppositely, divalent grafting using carbene-based addition reactions is found to leave the nanotube electronic properties unaltered [2]. We discuss the mechanisms behind these results based on symmetry and conjugation considerations. Second, high-resolution lithography patterning and aryldiazonium chemistry are used to add covalent adducts on various portions of carbon nanotubes devices, from several microns down to 20-nm segments. The intensity of conductance alteration is found to scale exponentially with the length of the exposed segment, with large variations in decay constants between devices. All devices nevertheless present a robust 20% current drop for the shortest exposed segments, which points to a consistent small number of binding sites. Finally, we demonstrate the ability of this approach to bind few molecules onto carbon nanotubes with controlled position and high yield over arrays of hundreds of devices, which opens a very promising route for assembling a variety of carbon-nanotube-based single-molecule electronic nanosensors.
[1] D. Bouilly, J. Laflamme-Janssen, J. Cabana, M. Côté, R. Martel, under revision (2014)
[2] D. Bouilly, J. Cabana, R. Martel. Appl. Phys. Lett. 101, 053116 (2012)
(Invited) Post-Growth Manipulation of Horizontally Aligned Single-Walled Carbon Nanotubes
Authors: Maruyama Shigeo , Inoue Taiki , Otsuka Keigo , Chiashi Shohei 
Published: February 2020

Horizontally aligned single-walled carbon nanotubes (SWNTs) are promising for electronic applications such as field-effect transistors (FETs). In addition to the density-controlled CVD growth [1,2] and chirality characterization of aligned SWNTs on quartz substrates, we will discuss two manipulation techniques of SWNT arrays. First is the full-length removal of metallic SWNTs by using organic film-assisted electrical breakdown, which gives semiconducting SWNT arrays suitable for scalable device fabrication [3]. We applied the electrical breakdown technique to SWNT array covered with organic films such as poly(methyl methacrylate) (PMMA) and realized that metallic nanotubes continues to burn as fuses for fireworks. This method yielded not only a high on/off ratio (~10,000) and fine spatial resolution (~55 nm) in the same way as in-air breakdown, but also long removal length (>10 µm) which is unattainable by conventional breakdown. Thermal calculations revealed that burned edges of a SWNT keep high temperature with oxidation heat generation of surrounding organic materials even after Joule heat stops. The second manipulation technique is the bundling of selected parts of SWNT arrays. Horizontally aligned SWNTs were peeled off from original substrates by using polymer films with lithographically-defined resist structures. Then, the resist was dissolved to give partially suspended SWNTs over trenched polymer films, and neighboring suspended SWNTs formed bundles by capillary process. Finally the structures were placed on target substrates to give partially bundled SWNTs. This technique would be available for controlling percolative transport of SWNT networks.
Reference:
[1] S. Chiashi, H. Okabe, T. Inoue, J. Shiomi, T. Sato, S. Kono, M. Terasawa, S. Maruyama, J. Phys. Chem. C, 116 (2012) 6805.
[2] T. Inoue, D. Hasegawa, S. Badar, S. Aikawa, S. Chiashi, S. Maruyama, J. Phys. Chem. C, 117 (2013) 11804.
[3] K. Otsuka, T. Inoue, S. Chiashi and S. Maruyama, Nanoscale, 6 (2014) 8831.
(Invited) Flexible and Conductive Mxene/Carbon Nanotube Composite Paper for Energy Storage
Authors: Zhao Mengqiang , Ren Chang E. , Ling Zheng , Lukatskaya Maria R. , Mashtalir Olha , Barsoum Michel W. , Gogotsi Yury 
Published: February 2020

Carbon nanomaterials, such as carbon nanotubes (CNTs), are attracting much attention as candidates for electrodes of energy storage devices due to their large open surfaces and high conductivity. Recently, MXenes, a new family of 2D carbides, have shown their great promise for electrodes in supercapacitors and Li-ion batteries. [1, 2] Herein, our new results show that the incorporation of CNTs into MXene films results in composite papers with much improved performance. [3]
Free-standing sandwich-like MXene/CNT composite papers composed of alternating layers of MXene and CNTs were fabricated by vacuum filtration method. The resulting “papers” have good flexibility, high electrical conductivity and a structure accessible to electrolyte ions. They exhibit much better performance than pure MXene films and the randomly mixed MXene/CNT composite papers. When employed as electrodes for supercapacitors in aqueous electrolyte, capacitances of ~390 F/cm3 were achieved. Besides, the composites showed ~75% increase in rate performance compared to pure MXene films and exhibited no capacity degradation after 10,000 cycles. The MXene/CNT composite papers can also serve as stable anodes for high-rate Li-ion batteries. Highly reversible and stable capacity of ~250 mAh/g was yielded by the titanium-based MXene/CNT composites at 0.5 C (2 hrs charge/discharge), about 10 times of that for pure MXene films. The niobium-based MXene/CNT composites achieved a high reversible capacity of ~650 mAh/g at 0.1 C (10 hrs charge/discharge). At 10 C (6 min charge/discharge), a reversible capacity of ~300 mAh/g was retained for >300 cycles, indicating excellent rate performance and cycling stability. These conductive, flexible and mechnaically strong papers are promising materials that can be used in wearable or structural electrochemical energy storage and conversion systems.
[1] M. Naguib, et al., MXenes: A New Family of Two-Dimensional Materials, Advanced Materials, 26, 992-1005 (2014)
[2] M. R. Lukatskaya, et al., Cation Intercalation and High Volumetric Capacitance of Two-dimensional Titanium Carbide, Science, 341, 1502-1505 (2013)
[3] M. Q. Zhao, et al. Flexible MXene/Carbon Nanotube Composite Paper with High Volumetric Capacitance, Advanced Materials, in press (2014)
Tayloring of Reduction Potential of Carbon Nanotubes Hybrid Compound By Substrate Interaction Probed By Metal Deposition
Authors: Macedo Nadia Guerra , Matsubara Elaine Yoshiko , Rosolen Jose Mauricio 
Published: February 2020

The determination or alteration of oxi-reduction potentials and Fermi level (EF) of single-walled carbon nanotubes is a relevant issue in the science of carbon nanotubes (CNTs) because many of the envisaged applications may involve charge transfer. So far, it is well known that redox potential and EF of single-walled carbon nanotubes are correlated to inverse of diameter and chiral angle. The reduction potential or the conduction band bottom energy of SWCNTs is in the range of 3.7 to 4.7 V vs. vacuum1,2. Nevertheless, in many electrochemical devices the CNTs is found on surface of other materials as oxides, carbons, metals, for instance. CNTs can also be directly grown on surface of several micrometric granules, fiber, thin films resulting, indeed, in hybrid compounds whose physical-chemical properties appears often correlated with amount and/or eventual electronic interaction of constituents. Herein, we investigate the eventual influence of a micrometric substrate on reduction potential of CNTs grown on its surface. Particularly, several carbonaceous materials and TiO2 were studied and the CNTs were vertically grown on surface of these micrometric substrates by chemical vapor deposition using the same CNTs growth protocol. In order to access the reduction potential of CNTs, the CNT/micrometric compounds were dipped into solutions of Ag, Cu, Al, Pd salts. The CNTs extracted from substrate by mechanical treatment were also dipped in same solutions. Afterwards, the obtained samples were analyzed in scanning electron microscopy, EDS and XPS after washed in deionized water. Interestingly the presence of metal nanoparticles was detected only in some types of CNT/micrometric substrate compounds. The mechanism of reduction of metals on surface of CNTs seems to be correlated with the participation of counter ions or presence of acids which can functionalize the surface of CNTs with COOH, COH, C=O groups. However, the main finding was the detection of an electronic coupling between CNT network-substrate which can modify the reduction potential of CNTs bear on its surface. Therefore, the CNTs growth on a micrometric substrate can lead to production of hierarchical hybrid compounds with unique redox potential.

[1] Hirana, Y. et al. Empirical Prediction of Electronic Potentials of Single-Walled Carbon Nanotubes With a Specific Chirality (n,m). Sci. Rep. 3, 2959; (2013).
[2] Kim, K. Ki et al.Doping strategy of carbon nanotubes with redox chemistry. New J.Chem.34, 2183; (2010).
Ultracompressible, High Rate Supercapacitors from Graphene-Coated Carbon Nanotube Aerogels
Authors: Wilson Evan , Islam Mohammad F. 
Published: February 2020

The advent of flexible and wearable electronics has led to significant investigation into electrochemical energy sources, in particular electrochemical capacitors (ECs), which can be reversibly deformed without significant loss of performance. There exists a wide array of electrode materials and designs for ECs that are capable of withstanding bending or stretching loads, however very few structures are capable of withstanding significant compressions without loss of properties or plastic deformation. Most successful designs incorporate pseudocapacitive materials like conducting polymers or metal oxides for structural stability, increasing energy but potentially hurting lifetime and capacitance stability of the cells. This work seeks to solve this problem by utilizing an ultracompressible graphene-coated carbon nanotube aerogel as an electrode that possesses a high capacitance and mechanically robust structure without the need for pseudocapacitive materials.
We have previously demonstrated the synthesis of an ultracompressible, superelastic aerogel by coating the struts and nodes of a single-walled carbon nanotube network1 with one- to few-layer graphene.2 These aerogels are capable of withstanding significant (>90%) compressive strain without plastic deformation over many cycles. In addition, they have a highly porous and conductive structure with very large specific surface area, properties which are ideal for supercapacitor applications.
In this talk, I will present fabrication and structural characterization of graphene-coated carbon nanotube aerogels, in addition to their electrochemical performance. The electrodes displayed near-ideal capacitive performance under high-rate operation with no loss of capacitance at 90% compression in both aqueous and room-temperature ionic liquid (RTIL) electrolytes. The transport properties of ions through the electrodes were unaffected by large compressive strains, allowing high-rate operation of cells with both uncompressed and compressed electrodes. Electrochemical impedance spectroscopy investigations confirm that the performance of the supercapacitor electrodes was largely strain-invariant. This performance, in cells with both uncompressed and compressed electrodes, was stable over hundreds of cycles. Moreover, the compression was exploited to construct cells with high volumetric capacitance of ~5 to 18 F/cm3 in aqueous and RTIL electrolytes respectively, nearly 50 times greater than comparable supercapacitor electrodes, while still allowing for rapid charging and discharging of the cells. This work was funded by the National Science Foundation through grants CBET-1335417 and DGE-0966227

References

1. K. H. Kim, Y. Oh and M. F. Islam, Advanced Functional Materials, 23, 377–383 (2012).
2. K. H. Kim, Y. Oh and M. F. Islam, Nature Nanotechnology, 7, 562–566 (2012).
(Invited) Electronic Scattering in One-Dimensional Carbon Nanotubes
Authors: Collins Philip G. 
Published: February 2020

A quasi-ballistic, semi-metallic carbon nanotube is a nearly ideal conductor for investigating scattering in the one-dimensional (1D) limit and for comparing experiment with theoretical predictions. Recently, we have developed high resolution Kelvin Probe force microscopy (KPFM) methods of characterizing transport in single nanotubes. KPFM images of potential gradients uniquely reveal the bias- and temperature-dependent mechanisms of scattering in nanotube devices, and clearly discriminate between contact effects and homogenous, diffusive scattering. Using this data, a comprehensive, quantitative model has been developed that includes intrinsic energy-relaxation processes, extrinsic interactions with the surrounding environment, and the effects of point defects. The new results show that the literature grossly underestimates the mean free path for optical phonon emission. Defect scattering follows a mechanism similar to Poole-Frenkel conduction but with modifications accounting for the 1D geometry. The Poole-Frenkel mechanism, which normally applies to 2D interfaces, has never been observed in the limit of a single defect limit, and its application to point defect scattering in 1D is wholly unanticipated in the theoretical literature. This presentation will summarize these findings and their implications for nanotube devices as sensors or digital electronics.
Dynamic and Steady State Optical Studies of Individual Covalent Dopant Sites in Single-Wall Carbon Nanotubes
Authors: Hartmann Nicolai F. , Yalcin Sibel E. , Haroz Erik H. , Ma Xuedan , Htoon Han , Doorn Stephen K. 
Published: February 2020

Controlled low-level covalent functionalization of single-wall carbon nanotubes (SWCNTs) has refocused the attention of the nanophotonics community on the use of SWCNTs as stable photon sources in imaging applications. Recently, a significant increase in photoluminescence (PL) quantum yield from the appearance of new emitting states was reported in the literature upon introduction of chemically stable oxygen [1,2] and aryl diazonium dopants [3]. Further insight into the chemical and electronic structure of oxygen trap sites was gained through low-temperature studies [4],however additional fundamental knowledge about the optical and chemical properties of these dopant sites is necessary in order to develop more efficient emitter and light harvesting systems based on SWCNTs.
We doped single-chirality-enriched (6,5) and (5,4) SWCNTs with a broad range of available covalent dopants and studied their steady-state and dynamic optical properties on the ensemble and single-tube level. Our refinement of the reported doping procedure described in the literature [1-3] enables the control of the doping level and type of dopant down to the introduction of individual dopant sites in a short timescale. Dual color imaging of 2 – 6 μm long SWCNTs reveals the red-shifted individual dopant emission E11* alongside the pristine E11 emission. Average ON times of single sites decrease with increasing electron withdrawing nature of the specific dopant groups as well as with an increase in pH of the surrounding medium which can be understood in terms of additional non radiative decay channels introduced through surface charging. In addition, we will present single tube lifetime measurements on covalently doped (5,4) SWCNTs for a variety of diazonium dopants. The brightening in dopant emission intensity is correlated with longer PL lifetimes and increases with the electron withdrawing strength of the associated functional groups.
[1] S. Ghosh, et al., Science, 2010,
330, 1656.
[2] Y. Miyauchi, et al., Nature Photon., 2013, 7, 715.
[3] Y. Piao, et al., Nature Chem., 2013, 5, 840.
[4] X. Ma, et al., ACS Nano, 2014, 8, 10782.
A Study on Correlation Between Elastic Deformation and Thermal Performance of Flexible Carbon Heater
Authors: Hong Young Kyu , Kim Byung-Ryang , Hong Chan Ho , Park Hyeon Ki , Shin Jin-Koog 
Published: February 2020

Printed carbon heater is one of most attractive alternatives to copper wire seat heater because of its uniform heat generation and trouble-free operation regardless of partial damage. Its superior characteristics such as low power consumption and rapid response induced a lot of research on carbon materials and its thermal performance. However, in contrast to the commercialization potential, application field related researches are not active yet. To apply a printed heater in a car seat, suitable elasticity is required without loss of thermal performance. Therefore, it needs to study on the correlation between deformation and electrical and structural characteristics.
In this study, we investigated relationship between elastic deformation and characteristics of carbon heater. Carbon heaters used in this study were screen printed on flexible polymer substrates of different elastic modulus. The carbon paste used to print the heater was made of graphite and amide functionalized MwCNT blended with polyester resin. The change of microstructure, electrical characteristics, and adhesion stability were analyzed in connection with the heater performance while increasing the deformation up to the elastic limit. Based on the analysis, we will discuss on critical factors determining the performance of flexible carbon heater under elastic deformation.
This research was financially supported by the Ministry of Trade, Industry and Energy (MOTIE) and Korea Institute for Advancement of Technology (KIAT) through the Promoting Regional Specialized Industry
(Invited) Promise of 2D Materials Beyond Graphene
Authors: Saptarshi Das 
Published: February 2020

Two dimensional systems, by the virtue of their unique material properties and excellent electrostatic integrity, provide immense opportunities not only to explore fundamental physics but also to solve critical technological problems. Graphene, Phosphorene, h-BN, MoS2, WSe2 and many others belong to this class of material which we are exploring. The fact that this class of materials contains metals, semiconductors, insulators and even superconductors at cryogenic temperature makes them extremely appealing across all scientific and engineering disciplines. In my talk I will demonstrate how “Contact Engineering” can be implemented to enhance the electrical performance of the 2D materials. Then I will talk about “Doping Constraints” and various “Scaling Aspects” of 2D materials. Finally I will discuss “Integration and Application” of 2D materials for flexible and transparent electronics as well as low power device design.
References:

Das, S. et al.

ACS Nano, 8 (11), 2014.

Das, S. et al.

Nano Letters, 14 (10), 2014.

Das, S. et al.

Applied Physics Letters, 105, 2014.

Das, S. et al.

Nano Letters, 14 (5), 2014.

Das, S. et al.

ACS Nano, 8 (2), 2014.

Das, S. et al.

Applied Physics Letters
, 103, 2013.

Das, S. et al.

Nano Letters, 13(7), 2013.

Das, S. et al.

Physica Status Solidi RRL,
7(4), 2013.

Das, S. et al.

Nano Letters
, 13(1), 2013
.
Facile and Controllable Synthesis of Heteroatom-Doped Carbon Nanotubes Under Atmospheric Pressure
Authors: Chang Yu-Chen , Chen Guan-Lin , Chiang Wei-Hung 
Published: February 2020

Recent theoretical and experimental studies have suggested that heteroatom-doped carbon nanomaterials such as carbon nanotubes (CNTs) and graphenes as novel materials with exceptional properties for applications including nanoelectronics, energy storage [1], fuel cells [2], and electrochemical sensing [3]. However, current synthesis methods of heteroatom-doped carbon nanomaterials usually involve complicated vacuum systems, making it difficult to enable industrial-scale production. Consequently, the development of a controllable synthesis of heteroatom-doped carbon nanomaterials at atmospheric pressure will lead to important advances on both scientific studies and innovation applications.
Here we demonstrate an atmospheric-pressure, solution-assisted substitution method to produce heteroatom-doped CNTs with varying heteroatoms including boron (B), sulfur (S), and phosphorus (P). Pristine multi-walled CNTs (MWCNTs) synthesized using a water-assisted chemical vapor deposition (CVD) were used as starting materials. The heteroatom-doped CNTs were then produced by heating the mixture of heteroatom precursor and MWCNTs under argon (Ar) atmosphere from 400 to 1200◦C for 1to 4 h at atmospheric pressure. We found that the heteroatom concentrations in the nanotubes could be tuned by controlling the reaction temperature and time, confirming by the X-ray photoelectron spectroscopy (XPS) and Raman characterizations. Detailed XPS characterization indicated that the S atoms were successfully doped into the sp2 graphene lattice of CNTs [Fig. 1(a)]. The high-resolution XPS (XPS) result reveals several C-S-O doping configurations existed in our as-produced samples [Fig. 1(b)]. The systematic Raman characterization was performed and shown the ratio of the D- and the G- bands (ID/IG) was increased for the as-produced samples, indicating the defect densities due to the doping process can be controlled in our method [Fig. 1(c)]. Thin-film electrical conductance characterization using four-point probe method suggested the electrical conductances of the as-prepared heteroatom-doped CNTs were significantly improved by heteroatom doping [Fig. 1(d)], making them useful materials for electrochemical-base applications. It is also noteworthy from a practical point of view that the developed atmospheric-pressure synthesis method is amenable to industrial-scale production since it avoids the need for a vacuum system.

Reference

[1] J. Han, L.L. Zhang, S. Lee, J. Oh, K.-S. Lee, J.R. Potts, J. Ji, X. Zhao, R.S. Ruoff, S. Park, ACS nano, 7 (2012) 19-26.
[2] L. Qu, Y. Liu, J.-B. Baek, L. Dai, ACS Nano, 4 (2010) 1321-1326.
[3] Y. Wang, Y. Shao, D.W. Matson, J. Li, Y. Lin, ACS nano, 4 (2010) 1790-1798.
[4] H. Liu, Y. Liu, D. Zhu, Journal of Materials Chemistry, 21 (2011) 3335-3345.

Figure 1