bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous and Individual Determination of Six Redox-Active Biomolecules Using a Modified Graphite Paste Electrode with Immobilized Ferric Cyanide-Chitosan Polymer Ion Pair on the Multi-Walled Carbon Nanotubes
Authors: Li Shaopei , Noroozifar Meissam , Kerman Kagan 
Published: May 2020

Redox-active biomolecules such as Ascorbic acid (AA), Dopamine (DA), Uric acid (UA), Tryptophan (Trp), Xanthine (XA), and Caffeine (CA) are all critical for biological homeostatic maintenance. The depletion or over consumption in any of the biomolecules can lead to detrimental effects. For example, previous reports have suggested the depletion of dopamine in the brain is highly correlated to the progression of Parkinson’s disease 1. Caffeine, though not a bio-molecules, it is frequently consumed, and overdose can lead to neurological damage, or even death 2,3. In extension, these bio-molecules tend to exists as a mixture. Thus, it becomes important to develop a platform that enables the monitoring of these biomolecule concentrations simultaneously.
In recent years, carbon nanotubes have collected a great amount of attention from the electrochemical sensor development communities 4. Due to their high surface to volume ratio, carbon nanotubes are able to enhance the electrical catalytic activity increasing the overall conductance 5. This characteristic is highly essential as not only it can increase the potential application range, it can also resolve and separate for biomolecules that have overlapping redox-potentials. In addition, nanotubes are highly biocompatible and do not pose a toxic effect on the biological system. In this work, a novel immobilized ferric cyanide-chitosan polymer ion pair on the multi-walled carbon nanotube-based nanocomposite was synthesized and utilized for the construction of a sensor platform capable of simultaneously detecting six redox-active biomolecules.
Using Fourier-transform infrared spectroscopy, and scanning electron microscopy, the nanocomposite was shown to be successfully synthesized. Cyclic voltammetry, and electrochemical impedance spectroscopy both demonstrated the final modified electrode has improved electrochemical activity. Using differential pulse voltammetry, AA, DA, UA, Trp, XA, and CA were all detected simultaneously (Shown in Figure 1). Finally, the sensor performance was analyzed in real samples and demonstrated a comparable performance. These results demonstrated the reported sensor has a strong potential to become the next generation of biosensors.

Reference

1. A. Nobili et al., Nat. Commun., 8, 14727 (2017).
2. J. W. Daly, Cell. Mol. Life Sci., 64, 2153–2169 (2007).
3. B. J. Gurley, S. C. Steelman, and S. L. Thomas, Clin. Ther., 37, 275–301 (2015).
4. J. Wang, Electroanalysis, 17, 7–14 (2005).
5. A. Eatemadi et al., Nanoscale Res. Lett., 9, 1–13 (2014).

Figure 1
Stimuli-Responsive Molecule Modification to Locally Functionalized Single-Walled Carbon Nanotubes for Wavelength Switching of Near Infrared Photoluminescence
Authors: Shiraki Tomohiro , Nakagawa Yasuto , Nakashima Naotoshi , Fujigaya Tsuyohiko 
Published: May 2020

Single-walled carbon nanotubes (SWNTs) with semiconducting features show near infrared (NIR) photoluminescence (PL). Defect doping to the SWNTs has been found to enhance the PL properties, which is achieved by local chemical modification.[1-9] It allows us to functionalize various molecules on the doped sites and such locally functionalized SWNTs (lf-SWNTs) show PL property changes depending on the modified molecules. For example; electronic property difference in the modified aryl groups induced PL shifts.[3] Moreover, protonation of amine groups[6] and molecular recognition at the doped sites[7,8] can be used for wavelength tuning. Therefore, stimuli responsiveness in the NIR PL properties could be designed in the lf-SWNTs through molecular approaches. In this presentation, we report reversible wavelength modulation based on molecular structure changes occurring at the doped sites by external stimuli. Molecular binding through covalent bond formation and photo-induced structural changes are used for the wavelength switching processes.
Imine chemistry is based on a condensation reaction of aldehyde and amine groups that occurs just by mixing the corresponding compounds. Owing to the reversibility of this reaction system, multistep wavelength switching of the NIR PL was conducted by imine bond formation, exchange or dissociation reactions of the imine bond, and Kabachnik-Fields reactions at the doped sites of the lf-SWNTs.[9] Photo-induced switching of the NIR PL was performed by creating the doped sites functionalized with photochromic molecules that showed color changes (= electronic property changes) by light irradiation. The photo-induced reversible structural changes of the modified molecules on the lf-SWNTs were observed by absorption spectroscopy, which accompanies spectral shifts of the NIR PL of the lf-SWNTs. Details including the relationship between PL shifts and molecular structure changes will be discussed at the meeting.
[1] B. Weisman et al. Science, 330, 1656 (2010). [2] Y. Miyauchi et al. Nat. Photon., 7, 715 (2013). [3] Y. Wang et al. Nat. Chem., 5, 840 (2013). [4] S. Doorn et al. Nat. Photon., 11, 577 (2017). [5] T. Shiraki et al. Sci. Rep., 6, 28393 (2016). [6] Y. Wang et al. J. Phys. Chem. C, 119, 3733 (2015) [7] T. Shiraki et al. Chem. Commun., 52, 12972 (2016). [8] T. Shiraki et al. Chem. Eur. J., 24, 9393 (2018). [9] T. Shiraki et al. Chem. Eur. J., 24, 19162 (2018).

Figure 1
Nanomachining of Carbon Nanotubes to Carbon Nanoribbons
Authors: Das Suprem R. 
Published: May 2020

Carbon Nanotubes (CNTs) have revolutionized number of scientific fields such as electronics, composites and biomedical engineering. However, our current ability to manipulate nanotube geometry is limited to only in the in-situ growth reactors. Expanding the knowledge of manipulating materials at nanoscale, such as the CNTs with alternate techniques, will significantly increase their potential for applications such as sensors and as well as bring new physical phenomena. Alternatively, graphene has its numerous success in last nineteen years except being a serious candidate for field effect applications. Nanomachining carbon nanotubes, which may produce altering structural and thus electronic properties, has not been well developed especially in the context of chemical free methods. We are exploiting ultrafast laser matter interactions at Kansas State University to nanomachining CNTs to produce carbon nanoribbons (CNRs) of sub-20 nanometer width and understand their properties. Laser micromachining has numerous applications for current and future technology developments, including those in aerospace and biomedical applications. Such a method to turn CNTs to CNRs will have future electronic and photonic applications.
This work is supported by U.S. National Science Foundation (NSF), funding from Kansas State University and David and Lynda Dawson Carl and Mary Ice Keystone Research funding.
(Invited) DNA-Directed High-Precision Assembly of CNT FETs
Authors: Zhao Mengyu , Chen Yahong , Wang Kexin , Streit Jason , Fagan Jeffrey A. , Tang Jianshi , Zheng Ming , Zhu Zhi , Sun Wei 
Published: May 2020

Precise fabrication of semiconducting channel materials into densely-aligned uniformly parallel arrays is one prerequisite to the high-performance ultra-scaled technology nodes, in particular for carbon nanotubes (CNTs). Traditional thin-film-based approaches generally yield CNTs in irregularly-spaced bundles or with wide orientation distribution, and lack a mechanism to effectively eliminate mis-aligned CNTs from the ultra-scaled channel area. Therefore, the averaged pitch value and precision of CNT arrays, the key parameters defining lateral CNT spacing, fail to simultaneously meet all of the patterning requirements for the ultra-scaled technology nodes. Bio-fabrication is promising for patterning CNTls at a resolution beyond the existing lithographic limit. However, impacted by surface charges and sub-micron dimensions of typical bio-templates, current bio-templated electronics exhibit both poor transport performance and array uniformity smaller than 1 micron.
We report precise scaling of inter-CNT pitch using a supramolecular assembly method called Spatially Hindered Integration of Nanowire Electronics (SHINE). Specifically, by using nano-trenches to align CNTs and DNA hybridization to stabilize them in place, we constructed parallel CNT arrays with uniform pitch as small as 10.4 nm, at an assembly yield over 95%. The pitch precision improves on that prepared from conventional thin-film approaches by more than two orders of magnitude. Compared to the lithography-patterned Si channels at 10 nm technology node, SHINE simultaneously provides both 70% smaller averaged pitch value and molecular-scale pitch precision in the channel area. By engineering the interfacial compositions, metal ions and surface charges that are destructive to FET performance have been excluded from the channel area without degrading CNT alignment. Under a source-to-drain voltage of -0.5 V, we demonstrate both transconductance more than 0.6 mS/μm with fast on/off switching. And the key FET performance metrics are improved by more than one order of magnitude than previous bio-templated FETs. Furthermore, we demonstrate centimeter-scale alignment of fixed-width CNT arrays. At the interface of high-performance electronics and bio-molecular self-assembly, precise bio-fabrication could provide ultra-scaled devices or circuits compatible with or sensitive to local biological environments.
(Invited) Ultrasonication-Induced Inner Shell Extraction from Double‐Wall Carbon Nanotubes: Characterisation By Ultracentrifugation and in Situ Raman and Fluorescence-Excitation Spectroscopy
Authors: Wenseleers Wim , Erkens Maksiem , Cambré Sofie , Flahaut Emmanuel 
Published: May 2020

We show that ultrasonication readily extracts inner tubes from double-wall carbon nanotubes (DWCNT), and characterize the process by density gradient ultracentrifugation (DGU) combined with in situ spectroscopic characterization in the density gradient. Our observations also cast new light on the question whether or not the inner tubes of DWCNTs fluoresce, which has been the subject of a long-standing debate, even though single‐DWCNT experiments have already shown drastic PL‐quenching for the inner CNT [1]. Indeed, in previous studies to characterise the PL from DWCNTs, they were typically solubilised using sonication, while here we see that upon sonication, the extraction of the inner tubes from the DWCNTs leads to much more efficiently fluorescing SWCNTs. First, the DWCNTs were purified from SWCNTs and bundles using density gradient ultracentrifugation (DGU). Then, sonication is applied, after which the extracted inner tubes were separated from the DWCNTs by DGU and characterised by in situ resonant Raman and PL‐spectroscopy as a function of height in the centrifuge tube [2]. These subsequent in situ DGU experiments unambiguously prove the extraction of inner SWCNTs from DWCNTs, even by very brief sonication, and sonication-time-dependent measurements show that the process quickly saturates.
[1] D. Levshov, R. Parret, H.-N. Tran, T. Michel, T.T. Cao, V.C. Nguyen, R. Arenal, V.N. Popov, S.B. Rochal, J.-L. Sauvajol, A.-A. Zahab, M. Paillet, Phys. Rev. B
96, 195410 (2017).
[2] S. Cambré, P. Muyshondt, R. Federicci, W. Wenseleers, Nanoscale
7, 20015 (2015).
Exploring the Impact of Counterion Chemistry on Carrier Doping of Carbon Nanotubes
Authors: Ferguson Andrew John , Blackburn Jeffrey L. 
Published: May 2020

Semiconducting single-walled carbon nanotubes (s-SWCNT) are viewed as a promising candidate for optical, electronic, and energy conversion applications. Often the performance of carbon nanotubes in these applications is dependent on being able to control the interplay between their optical and electronic properties. One strategy toward achieving this control is tuning the position of the Fermi level through chemical doping to inject charge carriers into the electronic density of states.
We have previously demonstrated that p-type doping using the one-electron oxidant, triethyloxonium hexachloroantimonate (OA) results in very efficient injection of free carriers into near-monochiral s-SWCNT networks. Here we build on our previous work by employing a series of charge-transfer dopants based on boron clusters appended with various organic moieties that control the redox properties of the dopant. These dopants are unique, since their chemical structure means that the electron that is extracted from the nanotube is localized on the boron cluster and spatially separated from hole density injected into the carbon nanotube. We explore the charge-transfer doping process using these boron-cluster dopants, the resulting charge-carrier transport properties of the doped s-SWCNT networks, and make a comparison to networks doped using either OA or 2,3,5,6-Tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ). We will present spectroscopic and bulk conductivity measurements of charge-transport in high-mobility s-SWCNT networks and will discuss the impact that the chemistry and structure of the dopant counterion has on charge transport and the implications for electronic devices comprised of these tailored s-SWCNT networks.
(Invited) Photoluminescent Property Modulation of Locally Functionalized Single-Walled Carbon Nanotubes Based on Molecular Factors in Bis-Aryl Functionalization
Authors: Shiraki Tomohiro , Yu Boda , Niidome Yoshiaki , Fujigaya Tsuyohiko 
Published: May 2020

Photoluminescence (PL) in the near infrared (NIR) region is applicable to bioimaging and telecommunication devices. Single-walled carbon nanotubes (SWNTs) with semiconducting features show NIR PL whose properties are governed by photogenerated excitons in the one-dimensional nanostructures. Defect doping to SWNTs is gathering great attentions due to enhance the contribution of the excitons to PL. The doped sites work as emissive sites with narrower bandgaps and exciton trapping features. As a result, additional PL (E
11*) with red-shifted wavelengths and enhanced quantum yields newly appears compared to original PL (E
11) of pristine SWNTs.[1-9]
Local chemical modification for the defect creation achieves molecular functionalization of the defect-doped sites of the tubes, providing locally functionalized SWNTs (lf-SWNTs). They are found to show PL modulation based on the functionalized molecules. Here, we report bis-aryl functionalization for proximal defect doping of lf-SWNTs, in which molecular structure effects of bis-aryl diazonium modifiers and microenvironmental effects of the doped sites are discussed.
Bis-arydiazonium salts (bAs) that had two reactive aryldiazonium groups connected with a methylene linker were synthesized and reacted with solubilized SWNTs for local functionalization. For PL wavelength modulation, the linker effects were examined by changing the connected positions on the aryl groups (pbAs for para and mbAs for meta) and the length of methylene chains.[5,8] In PL spectra of the synthesized lf-SWNTs (lf-SWNTs-pbA and lf-SWNTs-mbA), peaks appearing over 1200 nm (E
11
2*) changed sensitively depending on the chemical structures of bAs. In addition, the E
11
2* PL showed unique wavelength shifting behaviors by microenvironment changes using various organic solvents, which was different from those of E
11 PL and E
11* PL.[9]
Thus, bis-aryl functionalization in lf-SWNTs creates the doped sites whose properties are different from typical doped sites showing E
11* PL and would be useful for fundamental understanding of this material and developing modulation techniques of the longer wavelength NIR PL.
[1] B. Weisman et al. Science, 330, 1656 (2010). [2] Y. Miyauchi et al. Nat. Photon., 7, 715 (2013). [3] Y. Wang et al. J. Am. Chem. Soc., 138, 6878 (2016). [4] S. Doorn et al. Nat. Photon., 11, 577 (2017). [5] T. Shiraki et al. Sci. Rep., 6, 28393 (2016). [6] Y. Maeda et al. Nanoscale, 8, 16916 (2016) [7] T. Shiraki et al. Chem. Commun., 53, 12544 (2017). [8] T. Shiraki et al. Chem. Lett., 48, 791 (2019). [9] T. Shiraki et al. Chem. Commun., 55, 3662 (2019).

Figure 1
(Invited) Nanotube-Based Nanohybrids Made of Dyes Encapsulated inside Nanotubes
Authors: Martel Richard 
Published: May 2020

The inner and outer surfaces of a nanotube made of either carbon or boron nitride materials can be functionalized to tailor the chemical and optical properties of the assembly. Our studies on the optical properties of dyes encapsulated in nanotubes show for instance enhancement effects in both Raman and fluorescence spectroscopies, which are interesting for making optical nanoprobes for bio-imaging. Chemical functionalization of the outer wall has also been effective in promoting specific chemical interaction with a host, such as a biomarker. Here we will more specifically review our recent progress on the nanotube-based nanohybrids and focus the discussion on the case of the boron-nitride nanotubes for optical imaging. More particularly, we have made advances towards the preparation of boron-nitride nanotube nanohybrids for fluorescence imaging with visible and near-infrared emissions. Recent results on the outer functionalization to work more effectively in biological media and on the aggregation effects of encapsulated dyes probed optically in different conditions will be discussed.
This work was done in collaboration with E. Gaufrès, C. Allard, S. K. Mal, N. Tang, R. Nascimento, C. David, L. Durate, Louis Gaboury and S. Blais-Ouellette
(Invited) Optical Properties of Graphene Nanoribbons and Quantum Dots
Authors: Liu Thomas , Zhao Shen , Rondin Loïc , Chassagneux Yannick , Campidelli Stephane , Voisin Christophe , Lauret Jean-Sébastien 
Published: May 2020

Graphene is a key material for nanoelectronics. Nevertheless, its zero gap makes it unsuitable for applications needing semiconductors with sizeable energy gaps. One way to open a gap in graphene is to use size reduction effects. The reduction of one dimension leads to carbon nanotubes and graphene nanoribbons that are 1D carbon nanostructures. Reducing one more dimension leads to 0D graphene quantum dots. The optical properties of carbon nanotubes have been investigated for approximately 20 years, while the study of graphene quantum dots and nanoribbons is at its infancy.
Among potential application of these sp2 carbon nanostructures, the use of graphene nanoribbons and quantum dots as light emitters attracts a lot of attention. Here, I will present our recent results on the optical properties of graphene quantum dots synthesized by bottom-up chemistry [1].

References

[1] S. Zhao et al, Nature Communications 9, 3470 (2018)
(Invited) Dynamics of Nitrogen Functionalization of Graphene
Authors: Côté Michel , Malenfant-Thuot Olivier 
Published: May 2020

For graphene to be used eﬃciently in scientific and technological applications, its electronic properties need to be tailored to suit precise demands. The formation of a forbidden energy gap or the modification of the Fermi energy is achievable with functionalization techniques that simultaneously leave most of the atomic structure of graphene unchanged. Nitrogen functionalization is one of the most promising and studied types of treatment, in large part due to the proximity between carbon and nitrogen in the periodic table. It has already produced promising experimental results in the fields of high-sensibility biodetectors, field-eﬀect transistors, solar cells, and supercapacitors, among others.
To further understand this functionalization, we have performed an ab initio electronic structure study of different doping configurations and functionalization dynamics of nitrogen treatments of graphene. In particular, we have study the effect of simulation cell size used to carry our these calculations. We found that the inclusion of the special point K of the first Brillouin Zone in the momentum space sampling lowers formation energy results and should not be overlooked. Nudged Elastic Band calculations were also completed to study diﬀerent incorporation mechanisms from an adsorbed state to in-plane doping. In the presence of native defects, low barriers of 0.55 eV and 0.46 eV were obtained. When no defects are present, much larger barriers between 3.70 eV to 4.38 eV were found, which suggests an external source of energy is required to complete the incorporation.
In the second part of this presentation, we will report our result of using machine learning models to predict higher-level quantities. The goal of this work is to study the dependence of the Raman response of nitrogen functionalization of graphene. To simulate such a response, very large simulation cells need to be considered that would be out of reach for ab initio techniques, hence the use of machine learning methods to assist in the evaluation of the properties. Machine learning methods are now used more and more as a substitute for density functional theory calculations due to their low computational costs. However, in more advanced cases, relevant datasets are not always available, and the effort that would be necessary to generate the needed data suppress the advantages of using machine learning to speed up the calculations. Furthermore, the process of training a reliable model is not trivial and can also be expensive which should encourage the usage and diffusion of portable trained models.

Figure 1
(Invited) Scanning Gate Imaging of Charge Transport in Graphene Nanodevices
Authors: Brun Boris , Moreau Nicolas , Somanchi Sowmya , Nguyen Viet-Hung , Watanabe K , Taniguchi T , Stampfer Christoph , Charlier Jean-Christophe , Hackens Benoit 
Published: May 2020

Quantum transport in nanodevices is usually probed thanks to measurements of the electrical resistance or conductance, which lack the spatial resolution necessary to probe local-scale electron behavior. Here, we will discuss how to get real-space local information on peculiar quantum transport phenomena inside graphene constrictions. The results were obtained using low temperature scanning gate microscopy (SGM), which consists in mapping the electrical conductance of a device as an electrically-biased sharp metallic tip scans in its vicinity [1].
If the tip-induced perturbation is relatively small, SGM is an imaging technique giving access to the local density of states inside mesoscopic devices [2]. Here, we will focus on the regime of large tip-induced perturbation. This regime is particularly interesting in the case of graphene: depending on tip voltage and tip-sample distance, one can tune the shape, size, and smoothness of the moving scattering region associated with the tip, and eventually create a moving circular pn-junction within the device. We use this moving pn-junction to probe peculiar aspects of relativistic charge carrier dynamics within graphene devices: Klein tunnelling and current focusing and defocusing [3], Fabry-Pérot interferometry [4] and signatures of whispering gallery modes. This work unlocks new possibilities in the field of electron optics in graphene.
[1] M.A. Eriksson et al., Appl. Phys. Lett. 69, 671 (1996); M. Topinka et al., Science 289, 671 (2000).
[2] F. Martins et al., Phys. Rev. Lett. 99, 136807 (2007) ; M. Pala et al., Phys. Rev. B 77, 125310 (2008).
[3] B. Brun et al., Phys. Rev. B 100, 041401 (2019).
[4] B. Brun et al., arXiv:1911.12031.