bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Electrochemical Study of Graphene-Based Nanocomposites for Hydrogen Sorption and Storage
Authors: Boateng Emmanuel Q. , Thiruppathi Antony R. , Chen Aicheng 
Published: May 2020

With impending serious concerns associated with climate change and the depletion of fossil fuels, an envisaged hydrogen economy remains a viable alternative for addressing future energy issues. However, the significant technical challenges from vehicular hydrogen storage systems such as weight, efficiency, safety and cost constraints must be properly resolved before a commercial application is possible. Compared to compressed high-pressure and liquid hydrogen storage systems, storing hydrogen in solid systems via chemisorption and physisorption is emerging as a promising approach for hydrogen storage [1-3]. In this presentation, recent advances in the solid-state hydrogen storage with a high volumetric density are highlighted.
In addition, graphene-based nanomaterials have been considered as a promising candidate for hydrogen storage due to its lightweight and high surface area [4]. We have synthesized graphene oxide (GO), reduced graphene oxide (rGO) and boron-doped reduced graphene oxide (B-rGO) and investigated their performance for hydrogen storage. To enhance their capacity for hydrogen storage, the fabricated graphene oxide based nanomaterials were further modified with palladium (Pd) nanoparticles. The morphological features, structure and chemical compositions of the synthesized nanomaterials (GO, rGO and B-rGO) and nanocomposites (Pd/GO, Pd/rGO and Pd/B-rGO) were characterized using field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy and Raman spectroscopy, showing that Pd nanoparticles were uniformly dispersed on the B-rGO surface. Cyclic voltammetry and galvanostatic charging-discharging technique were employed to probe the hydrogen storage capacity of the graphene based nanomaterials and the nanocomposites. The effect of the boron substitution and the Pd nanoparticle decoration on the hydrogen storage are discussed.
References:
[1] A. Chen, C. Ostrom. Palladium-based nanomaterials: synthesis and electrochemical applications. Chem. Rev. 115 (2015) 11999 - 12044.
[2] S. Konda, A. Chen, Palladium based nanomaterials for enhanced hydrogen spillover and storage. Mater. Today 19 (2016) 100 - 108.
[3] E. Boateng, A. Chen, Recent advances in nanomaterials-based solid-state hydrogen storage. Mater. Today Adv. (2019) in press.
[4] S. K. Konda, A. Chen, One-step synthesis of Pd and reduced graphene oxide nanocomposites for enhanced hydrogen sorption and storage. Electrochem. Commun. 60 (2015) 148–152.
A One-Dimensional Carbon Nanotube‒Metalloporphyrin Hybrid Material for Lithium Storage
Authors: Jeong Kihun , Kim Ju-Myung , Lee Sang-Young 
Published: May 2020

Multi-redox organic and organometallic electrode materials have been emerging alternatives to the widespread inorganic counterparts in advanced power sources due to their design diversity, light weight, flexibility, and environmental benignity.1 However, their electrically insulating nature, limited capacity, and poor durability should be resolved for the practical application.
Here, we present a one-dimensional (1D) nanohybrid composed of a multiwalled carbon nanotube (MWCNT) core and a cobalt porphyrin shell (Figure) as a new class of electrode materials for rechargeable lithium batteries.2 Highly π-conjugated and multielectron redox-active meso-tetrakis(4-carboxyphenyl) porphyrinato cobalt (CoTCPP) shows strong noncovalent interactions with the MWCNT, leading to the successful formation of the 1D nanohybrid. The resultant nanohybrid, due to its structural uniqueness and maximal use of active areas, facilitates electron transport and electrolyte accessibility, which thus contribute to exhibiting a high specific capacity and improving redox kinetics. Furthermore, intrigued by the 1D structure of the nanohybrid, an all-fibrous nanomat electrode was fabricated through concurrent electro-spraying/-spinning processes. The nanomat electrode provides bicontinuous electron and ion conduction pathways, which eventually reveals the well-distinguishable lithiation behavior of CoTCPP and exceptional electrochemical performances with a long-term stability (ca. 226 mAh g
‒1
based on the electrode sheet weight at a current density of 5 C for over 1500 electrochemical cycles).
We hope that the material design strategy described in this study offers new insight into the development of high-performance electrode materials for next-generation power sources and energy storage systems.

References:

1. T. B. Schon, B. T. McAllister, P. F. Li, D. S. Seferos, Chem. Soc. Rev.
2016, 45, 6345.
2. K. Jeong, J.-M. Kim, S. H. Kim, G. Y. Jung, J. Yoo, S.-H. Kim, S. K. Kwak, and S.-Y. Lee, Adv. Funct. Mater.
2019, 29, 1806937.

Figure 1
(Invited) Exciton Dynamics in Air-Suspended Carbon Nanotubes Coupled to Nanobeam Cavities
Authors: Machiya Hidenori , Ishii Akihiro , Kato Yuichiro K. 
Published: May 2020

Air modes in photonic crystal nanobeam cavities offer efficient coupling to air-suspended carbon nanotubes [1,2]. Here we investigate exciton dynamics in the time domain at room temperature. The cavities are fabricated from silicon-on-insulator wafers, and nanotubes are synthesized over the cavities by chemical vapor deposition. Time-resolved photoluminescence measurements are performed on individual nanotubes, and we compare the bright exciton lifetime with and without coupling to the cavity. Purcell enhancement of the exciton recombination is observed [3].
Work supported in part by MIC (SCOPE 191503001), RIKEN (Incentive Research Projects), JSPS (KAKENHI JP16H05962), and MEXT (Nanotechnology Platform). H.M. is supported by JSPS Research Fellowship. We thank the Advanced Manufacturing Support Team at RIKEN for technical assistance.
[1] R. Miura, S. Imamura, R. Ohta, A. Ishii, X. Liu, T. Shimada, S. Iwamoto, Y. Arakawa, Y. K. Kato, Nat. Commun. 5, 5580 (2014).
[2] H. Machiya, T. Uda, A. Ishii, Y. K. Kato, Appl. Phys. Lett. 112, 021101 (2018).
[3] H. Machiya, A. Ishii, Y. K. Kato, in preparation.
Oxidized Multiwalled Carbon Nanotubes (ox-MWCNTs) As an Oxidation Agent for Pyrrole (PY) Polymerization: MWCNT@Polypy Composite Formation
Authors: Winkler Krzysztof , Wysocka-Zolopa Monika , Gradzka Emilia 
Published: May 2020

Composites of conducting polymers and carbon nanomaterials has attracted great attention both in fundamental and applied research. They exhibits high conductivity, large specific surface area, and excellent mechanical properties. These systems can be fabricated either by simple mixing of carbon material and conducting polymer or by in-situ oxidative polymerization of monomer in the presence of carbon nanostructures. Polypyrrole has been deposited on the SWCNTs or MWCNTs by chemical or electrochemical oxidation of monomer in solution containing carbon nanotubes. In the case of chemical polymerization, Fe(III) ions or are used as an oxidation agents. For the formation of MWCNT@polyPY composite, oxidized MWCNTs were used for pyrrole oxidation and polymerization process initiation.
MWCNTs were oxidized in solution containing hydrogen peroxide 30 wt% , sulphuric acid 96 wt%, and a mixture of H2SO4 96 wt% and H2O2 30 wt% in ratio 70:30. The oxidized MWCNTs were characterized with FTIR and Ramat spectroscopy, XPS, and thermogravimetric analysis. Nature of the functional groups and the presence of structural defects on the nanotube surface were determined. The MWCNTs oxidized in sulphuric acid and hydrogen peroxide mixture, containing ca. 5% of carboxylate groups were used as an oxidation agent for pyrrole polymerization. The composite was formed in toluene solution containing pyrrole and ox-MWCNTs. Polymer was deposited at the MWCNTs surface and the MWCNT@polyPY composite is formed (inset in Figure 1). The thickness of the polymeric layer coating the carbon nanotube surface (in range from 10 to 100 nm) can be controlled by the time of polypyrrole deposition, concentration of pyrrole in solution, and the stirring conditions.
The electrochemical properties of MWCNT@polyPY composites in different solutions were also investigated. The effects of the supporting electrolyte nature and the solvent were examined. Figure 1 shows the voltammetric behavior of MWCNT@polyPY thin layer deposited at the surface of gold electrode by drop coating method recorded in water containing NaClO4. Voltammogram exhibits two large oxidation peaks. The second one at ca. 0.4 V corresponds to the process of polypyrrole oxidation. The rate of oxidation process of polypyrrole that is deposited at the MWCNTs surface (MWCNT@polyPY) is much higher in comparison the oxidation of pristine polymer formed under conventional chemical conditions. Also, an efficiency of the polymer phase oxidation significantly increases in the case of composite. The nature of the large surface peak at ca. 0 V (Figure 1) is still under investigation.
Composite MWCNT@polyPY material can be used as an electroactive material in charge storage devices due to its capacitance properties and the fast rate of charge transfer.

Figure 1
(Invited) Photoswitchable Near-Infrared Emitters Based on Single-Walled Carbon Nanotube Hybrids
Authors: Godin Antoine G , Setaro Antonio , Gandil Morgane , Haag Rainer , Adeli Mohsen , Reich Stephanie , Cognet Laurent 
Published: May 2020

Super-resolution microscopy (SRM) has set a new paradigm in the field of optical imaging by delivering images with resolution much better than the diffraction limit. We demonstrated over the last years that such approaches can be designed to understand basic excitonic processes in carbon nanotubes [1-2]. In the field of bioimaging, SRM is currently limited to the visible range, missing the near-infrared region where biological tissues are however the most transparent. One reason for this is that single-molecule photoswitchable emitters, which are the basic ingredients to achieve single-molecule SRM, have not yet been developed in the near-infrared. To fill this gap, we have recently introduced a novel type of hybrid nanomaterials consisting of single-wall carbon nanotubes covalently functionalized with photo-switching molecules that are used to control the intrinsic luminescence of the single nanotubes in the near-infrared (beyond 1 µm) [3]. Through the control of photoswitching, we demonstrate super-localization imaging of nanotubes unresolved by diffraction limited microscopy opening the route toward SRM in the near-infrared for biological applications. Photocontrol of individual near-infrared emitters will also be highly desirable for elementary optical molecular switches or information storage elements since most communication data transfer protocols are established in this spectral range.

References

[1] Cognet et al Nanoletters, 8 (2008) 749 - 753.
[2] Danné et al. ACS Nano, 12 (2018) 6059
[3] Godin et al Science Advances, 5, (2019) eaax1166
(Invited) Photostability of Core-Shell Structures at Low Temperature
Authors: Orcin-Chaix Lucile , Campidelli Stephane , Rondin Loïc , Chassagneux Yannick , Voisin Christophe , Lauret Jean-Sébastien 
Published: May 2020

The use of carbon nanotubes as single emitters is currently developing. Being made only of surface atoms carbon nanotubes are very sensitive to their environment. A fingerprint of this sensitivity is the variation with time of their emission intensity (blinking) and energy (spectral jitter) in low temperature experiments. To improve the stability of nanotubes, we have synthesized core-double shell structures where two shells of polymers are rolled around the nanotube [1]. Here, we will show the influence of these shells on the stability of both the emission intensity and energy [2].
[1] L. Orcin-Chaix et al, Journal of Material Chemistry C 6, 4786 (2018)
[2] L. Orcin-Chaix et al, in preparation
(Invited) Origin of Lineshape Asymmetry in the Photoluminescence Spectra of Cryogenic Carbon Nanotubes
Authors: Högele Alexander 
Published: May 2020

Photoluminescence spectra of cryogenic carbon nanotubes exhibit a peculiar lineshape asymmetry that has been interpreted as arising from the interplay of temperature-driven exciton localization and the one-dimensional reservoir of acoustic phonons [1] with pronounced phonon sidebands in the limit of a gapped phonon reservoir [2,3]. Based on our recent experimental studies of PFO-wrapped nanotubes at cryogenic temperatures, we present an alternative model to explain the origin of the lineshape asymmetry.
[1] C. Galland et al., Non-Markovian decoherence of localized nanotube excitons by acoustic phonons, Phys. Rev. Lett. 101, 067402 (2008).
[2] F. Vialla et al., Unifying the low-temperature photoluminescence spectra of carbon nanotubes: The role of acoustic phonon confinement, Phys. Rev. Lett. 113, 057402 (2014).
[3] I. Sarpkaya et al., Strong acoustic phonon localization in copolymer-wrapped carbon nanotubes, ACS Nano 9, 6383 (2015).
Globally Aligned, Wafer-Scale Deposition of Carbon Nanotubes Via Interfacial Assembly
Authors: Jinkins Katherine R. , Gopalan Padma , Arnold Michael S. 
Published: May 2020

Floating evaporative self-assembly (FESA) is a solution-based technique for fabricating highly-aligned semiconducting carbon nanotube films.1,2 Field-effect transistors (FETs) based on carbon nanotubes aligned via FESA have exhibited current densities exceeding that of GaAs and Si, demonstrating the promise of this technique.3 However, the global uniformity of FESA films is poor, as the films are composed of stripes of aligned and randomly oriented carbon nanotubes. Additionally, this technique is inherently difficult to scale. In the work presented here, we demonstrate a scalable technique to overcome the shortcomings of FESA and to achieve globally uniform films of aligned carbon nanotubes at desirable packing densities for FETs.
In our technique, carbon nanotubes are continuously aligned across target substrates by lifting the substrates through a flowing nanotube ink/water interface. The ink/water interface collects and confines the nanotubes, which is vital to achieving a high degree of alignment. Polarized Raman spectroscopy mapping is used to quantify the degree of alignment in the resulting aligned nanotube films. The full width at half maximum (FWHM) of the alignment distribution within the films is 6.0° measured across a 1 mm2 area. We control the aligned carbon nanotube packing density from 0.2 to 59 µm-1 by varying the ink concentration from 0.1 to 100 µg mL-1. Using optimized conditions, we demonstrate the scalability of this technique by aligning carbon nanotubes across a 100 mm wide wafer. Charge transport measurements are performed using FETs with the aligned carbon nanotube films as the active channels, and the performance is compared to FETs based on FESA films.
1. Jinkins, K., R. et al. Nanotube Alignment Mechanism in Floating Evaporative Self-Assembly. Langmuir
33, 13407–13414 (2017).
2. Joo, Y., Brady, G. J., Arnold, M. S. & Gopalan, P. Dose-Controlled, Floating Evaporative Self-assembly and Alignment of Semiconducting Carbon Nanotubes from Organic Solvents. Langmuir
30, 3460–3466 (2014).
3. Brady, G. J. et al. Quasi-ballistic carbon nanotube array transistors with current density exceeding Si and GaAs. Sci. Adv.
2, (2016).
(Invited) Carbon Nanotube-Hybrid Nanoscale Devices
Authors: Palma Matteo 
Published: May 2020

The controlled organization of individual molecules and nanostructures with nanoscale accuracy is key for the fabrication of the next generation optoelectronic devices and the investigation of events in biological and chemical assays. In this regard, we developed different platforms based on the in-solution assembly of classes of molecular materials (organic, inorganic, and biological with promising attributes) to single-walled carbon nanotubes (SWCNTs), employed as building blocks that allow for nanoscale studies to be performed in a variety of research fields.
Through this approach, we assembled and investigated: molecular transport junctions,[1] metal nanowire devices using CNTs as vector templates,[2] static and dynamic organic-inorganic heterostructures consisting of Quantum Dot-CNT hybrids,[3,4] stimuli-responsive CNT-CdS/CNT-PbS devices[5] and DNA-CNT junctions,[6] protein-CNT nanohybrids,[7] and multiplexed biosensing devices based on aptamer- and protein-CNT heterostructures.[8,9] In this presentation, we will discuss relevant and recent examples among the aforementioned studies.
[1] Journal of the American Chemical Society, 2016, 138, 2905-2908
[2] Angewandte Chemie International Edition, 2019, DOI: 10.1002/anie.201902857
[3] Small, 2017, 13, 1603042
[4] Advanced Science, 2018, 5, 1800596
[5] Submitted

[6] Chemistry of Materials, 2019, 31, 1537-1542
[7] Journal of the American Chemical Society, 2017, 139, 17834-17840
[8] Nano Letters, 2018, 18, 4130-4135
[9] Submitted
Preclinical Imaging and Spectroscopy in the NIR-II Window with Single-Walled Carbon Nanotubes
Authors: Beaulieu Ouellet Emilie , Galassi Thomas Vito , Harvey Jackson Dean , Baker Hanan , Heller Daniel A. 
Published: May 2020

We developed a near-infrared small animal imaging system, IR VIVO, that provides real-time images, videos, and spectral imaging in the NIR-I and shortwave infrared (SWIR or NIR-II) regions. We found that SWIR wavelengths can give optimal resolution for in vivo optical imaging of deep organs in mice due to the low tissue autofluorescence, scattering and absorption of light at these wavelengths. We also show how this higher penetration depth can enable the detection of small wavelength changes in the emission of carbon nanotube-based sensors implanted in vivo using a continuously tunable filter.
First, we demonstrated superior image clarity and penetration depth at NIR-II wavelengths (1000-1700 nm) in vivo using an FDA approved dye, indocyanine green (ICG). We used 780 nm excitation and detection using a Zephir 1.7 InGaAs camera and 1250 nm long-pass emission filter. We found low tissue autofluorescence at 1250 nm. The ICG dye imaging resulted in superior visualization of microvasculature, perfusion, measurement of heart rate, respiratory rate, hepatobiliary, and intestinal contractions. Further anatomical and functional imaging was carried out by looking at the kinetics of ICG, resulting in identification of different organs.
In vivo near-infrared hyperspectral imaging of carbon nanotubes was conducted using a continuously-tunable filter in the imager. A diffraction volume Bragg grating (VBG), was used to provide narrow-band wavelength selection. Coupled with a homogeneous global illumination, spectrally-defined images were acquired in the entire field of view. The result was a dataset containing both 2D spatial information and the full spectrum for each point in the image. We conducted near-infrared hyperspectral imaging of single-walled carbon nanotubes to measure small wavelength changes of the nanotubes implanted into live mice. Hyperspectral measurements of carbon nanotube sensors for lipids in the liver as well as implantable sensors for doxorubicin were conducted, facilitating liver disease monitoring and drug pharmacokinetics measurements.
We believe wide-area NIR-II imaging and spectral/hyperspectral measurements have broad potential applications for the use of carbon nanotubes and other NIR-I/II materials in basic materials/biology, translational, and clinical work, including sensor arrays, point-of-care measurements, implants, whole-animal imaging, and intraoperative/surgical imaging.
Groove-Assisted Global Spontaneous Alignment of Carbon Nanotubes in Vacuum Filtration
Authors: Komatsu Natsumi , Nakamura Motonori , Ghosh Saunab , Kim Daeun , Chen Haoze , Katagiri Atsuhiro , Yomogida Yohei , Gao Weilu , Yanagi Kazuhiro , Kono Junichiro 
Published: May 2020

Recently, He and coworkers have developed a method for fabricating films of aligned single-wall carbon nanotubes (SWNCTs) using slow vacuum filtration [1]. Their fabricated SWCNT films are wafer-scale (centimeter size), highly packed (~ 1 nanotube per cross-sectional area of 1 nm2) and have nearly perfect alignment (nematic order parameter S ~ 1). However, the mechanism driving the aligned structures to grow into monodomains of macroscopic size has not been fully understood. In particular, what dictates the direction of SWNCT alignment has been under discussion. Here, we first examine a model suggested by He et al., where SWCNTs interact with each other and result in global alignment in a potential energy minimum near the surface [1]. We show experimental data that invalidates this model, suggesting that there must be a characteristic of the entire membrane that determines the alignment direction. We found a large number of parallel grooves that exist on most commercial filter membranes used for vacuum filtration, and show experimental results demonstrating that the grooves determine the direction of SWCNT alignment. Furthermore, when we eliminated the grooves by heating treatment, we observed multidomain alignment instead of monodomain alignment. Finally, we introduced intentionally created grooves on the filter membrane by an imprinting method, which successfully controlled the alignment direction. This procedure, groove-assisted CVF, provides a simple and reproducible way to align CNTs in a desired direction.
Reference:
[1] He, X.; Gao, W.; Xie, L.; Li, B.; Zhang, Q.; Lei, S.; Robinson, J. M.; Hároz, E. H.; Doorn, S. K.; Wang, W.; Vajtai, R.; Ajayan, P. M.; Adams, W. W.; Hauge, R. H.; Kono, J. Nat. Nanotechnol. 2016, 11, 633–638.
(Invited) Spontaneous and Intentional Exciton Trapping in Carbon Nanotubes
Authors: Raynaud Christophe , Chassagneux Yannick , Claude Théo , Borel Antoine , Zaumseil Jana , Lauret Jean-Sébastien , Voisin Christophe 
Published: May 2020

We use a combination of hyperspectral superlocalization microscopy and excitation photoluminescence spectroscopy techniques to study the localization of one-dimensional excitons in pristine and functionalized single wall carbon nanotubes at low and room temperature. Using numerical simulations, we interpret the nearly resonant excitation spectra either in terms of excited trapped states leading a selective excitation of a trap or in terms of delocalized one dimensional excitonic states. We discuss the implications of this localization for the use of carbon nanotubes as quantum-light emitters.
Raynaud et al. Nano Lett. 19, 7210 (2019)