bluuebunny/crossref_metadata_2025_split huggingface dataset:
Invited Presentation: Optoelectronic and Thermal Transport Properties of Carbon Nanotubes and Related Materials
Authors: Cronin Stephen B. 
Published: February 2020

I will report our latest results studying the optoelectronic properties and thermal transport characteristics of nanoscale materials and devices. In carbon nanotubes pn-junctions, we observe Zener tunneling behavior and photocurrent generation in quasi-metallic nanotubes1 and non-ideal diode behavior in semiconducting nanotube2. We observe enhanced photoluminescence and photocurrent in monolayer MoS2 under ionic liquid gating conditions due passivation of surface states. The Fabry-Perot resonance in GaAs nanowires can also be significantly enhanced through surface passivation and local field enhancement. Lastly, the thermal interface conductance across graphene/hexagonal boron nitride heterojunctions are measured using an electrical heating/optical measurement technique.
1. Amer, M.R., S.-W. Chang, R. Dhall, J. Qiu and S. Cronin, Zener Tunneling and Photocurrent Generation in Quasi-Metallic Carbon Nanotube pn-Devices. Nano Letters, DOI: 10.1021/nl402334e (2013).
2. Chang, S.-W., K. Bergemann, R. Dhall, J. Zimmerman, S. Forrest and S. Cronin, Non-ideal Diode Behavior and Band Gap Renormalization in Carbon Nanotube P-N Junctions. IEEE Transactions on Nanotechnology, DOI: 10.1109/TNANO.2013.2287124 (2013).
Invited Presentation: Optical Detection of Individual Carbon Nanotubes: Nanotube Spectroscopy and Bioimaging
Authors: Cognet Laurent 
Published: February 2020

The optical microscopy of single molecules has recently been beneficial for many applications, in particular in biology. It allows a sub-wavelength localization of an isolated nano-object and a subtle probing of its spatio temporal nano-environment on cells as demonstrated on live neurons [1].
For many bio-applications, near infrared nanoprobes and/or more photostable nanoprobes than conventional fluorescent molecules or quantum dots are desirable. In this context, single walled carbon nanotube tubes are promising. A prerequisite is however to understand their optical properties in different environments including water/saline suspensions, to study their rheological/interaction behavior in crowded bio/cellular environments and further optimize their optical detection therein. Our current efforts toward these goals will be presented and comparisons with other near infrared probes will be performed [2].

References

[1] L. Groc, M. Lafourcade, M.Heine, M. Renner, V. Racine, J.-B. Sibarita, B. Lounis, D. Choquet & L. Cognet, J. Neuroscience, 27, 12433 (2007); M. Heine, L. Groc, R. Frischknecht, JC. Béïque, B. Lounis, G. Rumbaugh, RL. Huganir, L. Cognet, D. Choquet, Science, 320, 201 (2008).
[2] L. Cognet, D. Tsyboulski, J. Rocha, C. Doyle, J.M. Tour, R.B. Weisman, Science, 316 1465 (2007); N. Fakhri, FC. MacKintosh, B. Lounis, L. Cognet L, M. Pasquali, Science, 330 1804 (2010); S. Cambré, S.Santos, W. Wenseleers, R.T. Nugraha, R. Saito, L. Cognet and B. Lounis, ACS Nano
6, 2649 (2012); J.G. Duque, L. Oudjedi, J. J. Crochet, , S. Tretiak, B. Lounis, S.K Doorn and L. Cognet JACS 135 (2013) 3379. E. Genin, Z. Gao, J. A. Varela, J. Daniel, T. Bsaibess, I. Gosse, L. Groc, L. Cognet, M. Blanchard-Desce Adv. Mat (2013) in press
Invited Presentation: Direct Measurement of the Absolute Absorption Spectrum of Individual Carbon Nanotubes
Authors: Blancon Jean-Christophe , Paillet Matthieu , Tran Huy Nam , Than Xuan Tinh , Aberra Guebrou Samuel , Ayari Anthony , San Miguel Alfonso , Phan Ngoc-Minh , Zahab Ahmed-Azmi , Sauvajol Jean-Louis , Vallee Fabrice , Del Fatti Natalia 
Published: February 2020

The unique optical properties of single-wall carbon nanotubes (SWNTs) are very promising for the development of novel opto-electronic components and sensors with applications in many fields. Despite numerous studies performed using photoluminescence or Raman and Rayleigh scattering, knowledge of their optical response is still partial, in particular direct and quantitative access to the intrinsic absorption characteristics of SWNT is still challenging. Their precise investigation is made difficult by the large heterogeneities of the carbon nanotube structural parameters in most synthesized ensembles, leading to measurement of mean properties. This can be avoided by performing optical investigations on individual nanotubes. We show here that the spatial modulation spectroscopy (SMS) technique, initially developed to quantitatively study the optical response of single metal nanoparticles1, can be applied to the investigation of individual SWNTs2,3. As compared to other optical techniques, SMS has the key advantage of being sensitive to the nano-object absorption and to directly measure its absolute absorption cross-section. Using this approach, we have determined, over a broad optical spectral range, the absorption spectrum of semiconducting individual SWNTs and the oscillator strength of their different excitonic resonances. A non-resonant background is also identified and its cross-section comparable to the ideal graphene optical absorbance. Furthermore, investigation of the same SWNT either free-standing or lying on a substrate shows large broadening of the excitonic resonances, as well as strong weakening of polarization-dependent antenna effects, due to SWNT-substrate interaction.
[1] A.Arbouet, D.Christofilos, N.Del Fatti and F.Vallée ; J-R.Huntzinger, L.Arnaud, P.Billaud and M. Broyer, Physical Review Letters 93, 127401 (2004).
[2] D.Christofilos , J-C.Blancon , J.Arvanitidis, A.San Miguel, A.Ayari, N.Del Fatti and F.Vallée, Journal of Physical Chemistry Letters 3, 1176 (2012).
[3] J.-C. Blancon, M. Paillet, H.N.Tran, X.T.Than, S. Aberra-Guebrou, A. Ayari, A. San Miguel, N-M. Phan, A-A. Zahab, J-L. Sauvajol, N. Del Fatti and F. Vallée, Nature Communications 4:2542 doi:10.1038/ncomms3542 (2013).
Invited Presentation: Single Molecule Bioelectronics with Carbon Nanotube Circuits
Authors: Collins Philip G. 
Published: February 2020

Nanoscale electronic devices like field-effect transistors have long promised to provide sensitive, label-free detection of biomolecules. In particular, single-walled carbon nanotubes have the requisite sensitivity to detect single molecule events, and they have sufficient bandwidth to directly monitor single molecule dynamics in real time.
Recent measurements have demonstrated this premise by monitoring the dynamic, single-molecule processivity of three different enzymes: lysozyme [1,2], protein Kinase A [3], and the Klenow fragment of DNA polymerase I [4]. With all three enzymes, single molecules were electronically monitored for 10 or more minutes, allowing us to directly observe rare transitions to chemically inactive and hyperactive conformations. The high bandwidth of the nanotube transistors further allow every individual chemical event to be clearly resolved, providing excellent statistics from tens of thousands of turnovers by a single enzyme. Besides establishing values for processivity and turnover rates, the measurements revealed variability, dynamic disorder, and the existence of intermediate states. Initial success with three different enzymes indicates the generality and attractiveness of the nanotube devices as a new tool to complement other single molecule techniques. Furthermore, our focused research on transduction mechanisms provides the design rules necessary to further generalize this architecture [5]. This presentation will summarize these rules, and demonstrate how the purposeful incorporation of just one amino acid is sufficient to fabricate effective, single molecule nanocircuits from a wide range of enzymes or proteins.
[1] Y. Choi et. al., Science 335319 (2012). [2] Y. Choi et. al., JACS 1342032 (2012). [3] P. Sims et. al., JACS 1357861 (2013). [4] T. Olsen et. al., JACS 1357855 (2013). [5] Y. Choi et. al., Nano Lett. 13 625 (2013).
Binding Configuration and Surface Coverage of Poly(9,9-dioctylfluorene-2,7-diyl) on Electronic Type-Sorted Carbon Nanotubes
Authors: Shea Matthew J , Brady Gerald J , Arnold Michael S 
Published: February 2020

Several schemes have been demonstrated to successfully extract semiconducting (s-) single-walled carbon nanotubes (SWCNTs) from heterogeneous as-grown mixtures containing metallic (m-) SWCNTs. The polyfluorene family of conjugated polymers, specifically poly(9,9-dioctylfluorene-2,7-diyl) (PFO), have been shown to extract s-SWCNTs from mixtures of s- and m-SWCNTs with high selectivity (>99% s-SWCNT) by preferentially wrapping the s-SWCNT components. In addition to electronic type, the selectivity is heavily dependent on the nanotube diameter and chiral angle. To date, there is an inadequate understanding of the polymer-CNT interactions that lead to the high preference for s- over m-SWCNTs in the wrapping process. It is vital to understand these parameters to design separation schemes to reduce the proportion of m-SWCNT impurities to technologically relevant ppm and ppb levels.
In this work, we explore the chemistry of non-covalent nanotube-polymer wrapping processes and describe the effects of surface coverage and binding configuration on the separation efficiency. We disperse SWCNTs grown by the HiPCO process, which contain many chiral species of SWCNT with diameters near 1 nm, in toluene solutions of varying PFO concentration. The resulting dispersions are analyzed with optical absorption spectroscopy, excitation-emission photoluminescence spectroscopy, and photoluminescence anisotropy. First, we experimentally quantify the amount of PFO wrapping the SWCNTs by measuring exciton energy transfer from PFO to SWCNTs via photoluminescence spectroscopy. We characterize the dependence of the surface coverage on PFO concentration, finding that the surface coverage increases by a factor of 7 as PFO concentration increases from 0.2 to 2 mg/mL. Second, we demonstrate that the wrapping of nanotubes by PFO is described by a Langmuir adsorption isotherm, in which surface coverage of PFO on the nanotubes follows an S-shaped curve as a function of PFO concentration. The shape of the curve is related to the polymer-nanotube binding energy, which depends on the nanotube electronic type, diameter, chiral angle, solvent, and polymer molecular weight. Third, we determine the binding configuration of the PFO on the nanotube surface as a function of PFO concentration and demonstrate that the PFO becomes more ordered as the surface coverage decreases. In the highly-ordered PFO regime we estimate the wrapping angle of individual PFO strands around nanotubes in solution. Finally, we find that the metal-semiconductor separation efficiency is lowest when the concentration of PFO is high, surface coverage is high, and surface ordering is low.
Understanding the PFO wrapping process will be an important step toward attaining high-purity s-SWCNT from this and similar sorting procedures for a range of polymer-CNT systems. These advances will enable further development of technologically relevant high purity s-SWCNTs for next-generation electronic devices.
Invited Presentation: Nitrogen-Incorporated Single-Walled Carbon Nanotubes for Devices
Authors: Maruyama Shigeo , Thurakitseree Theerapol , Kim Sungjin , Kramberger Christian , Chiashi Shohei , Einarsson Erik 
Published: February 2020

We synthesized single-walled carbon nanotubes (SWNTs) with small diameter and narrow diameter distribution using acetonitrile (AcN)-mixed ethanol (EtOH) feedstock. Due to the presence of nitrogen (N) during synthesis, the SWNT mean diameter was dramatically reduced from approximately 2.1 nm to less than 1 nm as AcN was added as carbon source [1, 2]. Surprisingly, the main nitrogen configuration was found to be encapsulated diatomic N2 molecules interior of SWNTs with the content of 1 at % [3, 4]. As the sequence of feedstock was switched during synthesis, SWNT diameter was changed along the vertically aligned array. A majority of nanotube junctions between two different diameter nanotubes were found to be discontinuous, while a minority of continuous junctions were revealed by high-resolution transmission electron microscope [5]. This diameter modulation was reversible upon the sequence of feedstock introduction. Additionally, the observed N2 molecules on the top of double-layered SWNT vertical array, where the top layer was EtOH-grown array, imply that encapsulated N2 molecules were migrating across nanotube junctions, indicating a viability of connected SWNTs with different diameters. We also address the role of nitrogen on influencing the SWNT diameter in which nitrogen affects only the surface of the catalyst particle, resulting in a change from the Octopus to the VLS growth mode, which results in a smaller diameter. Several devices using this nitrogen-incorporated SWNTs will be discussed.

References

[1] T. Thurakitseree, C. Kramberger, P. Zhao, S. Aikawa, S. Harish, S. Chiashi, E. Einarsson, S. Maruyama, Carbon
50 (2012) 2635.
[2] T. Thurakitseree, C. Kramberger, P. Zhao, S. Chiashi, E. Einarsson, S. Maruyama, Phys. Stat. Sol. B
249 (2012) 2404.
[3] C. Kramberger, T. Thurakitseree, H. Koh, Y. Izumi, T. Kinoshita, T. Muro, E. Einarsson, S. Maruyama, Carbon, 55 (2013) 196.
[4] C. Kramberger, T. Thurakitseree, E. Einarsson, A. Takashima, T. Kinoshita, T. Muro, S. Maruyama, Nanoscale, (2013), in press, (DOI: 10.1039/C3NR04729F).
[5] T. Thurakitseree, C. Kramberger, A. Kumamoto, S. Chiashi, E. Einarsson, S. Maruyama, ACS
Nano
7 (2013) 2205.
Maximum Aromaticity As a Guiding Principle for the Most Suitable Hosting Cages in Endohedral Metallofullerenes
Authors: Garcia-Borràs Marc , Osuna Sílvia , Swart Marcel , Luis Josep Maria , Solà Miquel 
Published: February 2020

Encapsulation of metal clusters in endohedral metallofullerenes takes place in cages that in most cases are far from being the most stable isomer in the corresponding hollow fullerenes. In large metal clusters and small fullerene cages, the election is mainly driven by the need to reduce strain. For the not so large metal clusters, it is usually said that the cage is chosen to minimize the electrostatic repulsion between charged five-membered rings.1 We have proved that maximizing the aromaticity is the main driving force that determines the most suitable hosting carbon cage for a given metallic cluster.2 This simple rule, the so-called Maximum ARomaticity Criterion (MARC), allow us to directly compare IPR (isolated pentagon rule) and non-IPR anionic isomers regardless the number of adjacent pentagon pairs (APP) they have. We have tested the MARC for the majority of endohedral metallofullerenes from C66 to C104 reported to date and the results show that MARC successfully predicts the most suitable C2n cage for hosting a given metal cluster among the manifold existing C2n isomers. In addition, using the Maximum ARomaticity Criterion, one can justify why the IPR rule is not always fulfilled when EMFs are considered.
[Figure 1 here]
Figure 1. Classification in terms of the ALA index of the anionic IPR and non-IPR fullerene isomers with 1-3 Adjacent Pentagon Pairs (APPs) for the most common C2
n (2n = 66–104) EMFs reported to date. Isomers experimentally observed are marked using black dots, and their corresponding isomer numbers are indicated. The ALA prediction ordering for the experimentally observed isomers are given in parentheses.

A. Rodríguez-Fortea, N. Alegret, A.L. Balch, J.M. Poblet, Nat. Chem.
2010, 2, 955.

M. Garcia-Borràs, S. Osuna, M. Swart, J.M. Luis, and M. Solà, Angew. Chem. Int. Ed.
2013, 52, 9275.
Fullerenes Encapsulating an Ytterbium Atom: Molecular Structures and Chemical Properties
Authors: Lu Xing 
Published: February 2020

Endohedral metallofullerenes (EMFs) are novel hybrid molecules with metal atoms or metal clusters being encapsulated inside fullerene cages.[1] In spite that the EMFs encapsulating divalent metal ions are less produced than other species, a series of mono-ytterbium have been successfully synthesized and isolated in our recent experiments. Their cage structures were systematically investigated with 13C NMR spectroscopy in combination with computational works.[2] To seek insights into the metal location and metal-cage interactions in these Yb@C2n (2n = 80, 82) compounds, their cocrystals with NiII(octaethylporphyrin) have been investigated with X-ray diffraction (XRD) crystallography.[3]

More meaningfully, chemical properties of divalent EMFs were investigated for the first time with a carbene probe. The isolated derivatives were systematically characterized with a collection of theoretical and experimental techniques, including single crystal XRD crystallography. Unique interplays between the internal divalent metal ion and the addend have been observed.[4]

References:
[1] X. Lu, L. Feng, T. Akasaka, S. Nagase, Chem. Soc.
Rev.
2012, 41, 7723-7760.
[2] X. Lu, Z. Slanina, T. Akasaka, T. Tsuchiya, N. Mizorogi, S. Nagase, J. Am. Chem. Soc.
2010, 132, 5896-5905.
[3] (a) X. Lu, Y. Lian, C. M. Beavers, N. Mizorogi, Z. Slanina, S. Nagase, T. Akasaka, J. Am. Chem. Soc.
2011, 133, 10772-10775. (b) M. Suzuki, Z. Slanina, N. Mizorogi, X. Lu, S. Nagase, T. Akasaka, J. Am. Chem. Soc.
2012, 134, 18772–18778.
[4] (a)Y-P. Xie, M. Suzuki, W. Cai, N. Mizorogi, S. Nagase, T. Akasaka, X. Lu, Angew. Chem. Int. Ed.
2013, 52, 5142-5145. (b) W. Zhang, M. Suzuki, Y-P. Xie, L. P. Bao, W. T. Cai, Z. Slanina, S. Nagase, M. Xu, T. Akasaka, X. Lu, J. Am. Chem. Soc.
2013, 135, 12730-12735.
Invited Presentation: Graphene Nanoelectromechanical Systems As Stochastic-Frequency Oscillators
Authors: Bockrath Marc , Miao Tengfei 
Published: February 2020

We measure the quality factor Q of electrically-driven few-layer graphene drumhead resonators, providing an experimental demonstration that Q ~ 1/T , where T is the temperature. We develop a model that includes intermodal coupling and tensioned graphene resonators, yielding good quantitative agreement to experiment. Because the resonators are atomically thin, out-of-plane fluctuations are large. As a result Q is mainly determined by stochastic frequency broadening rather than frictional damping, in analogy to nuclear magnetic resonance. Additionally, at larger drives the resonator linewidth is enhanced by nonlinear damping, in qualitative agreement with a recent theory of damping by radiation of in-plane phonons[1]. Parametric amplification produced by periodic thermal expansion from the ac drive voltage yields an anomalously large linewidth at the largest drives. Our results contribute towards a general framework for understanding the mechanisms of dissipation and spectral line broadening in atomically thin membrane resonators.
1. Croy, A.; Midtvedt, D.; Isacsson, A.; Kinaret, J. M. Phys. Rev. B 2012, 86, 235435.
Field-Controlled Ion Doping of Graphene
Authors: Kinder Erich , Lu Hao , Hwang Wan Sik , Cho Byung Jin , Hong Seul-ki , Seabaugh Alan , Fullerton-Shirey Susan 
Published: February 2020

Doping technologies are needed for the development of tunnel field-effect transistors based on graphene and other single-layer two-dimensional materials. Here we utilize Li+ and ClO4
− ions in polyethylene oxide (PEO) to enable dynamic and reconfigurable doping of graphene under electric field control. Ions are drifted across the PEO to the graphene where they induce electron or hole conductivity. Use of PEO:LiClO4 for ion-doping of carbon nanotubes [1], graphene [2, 3] and MoS2[4] have all incorporated the ion conductor and field plate above the transistor channel. This requires a dry process because the developers used in photolithography attack and contaminate PEO. This further restricts the field plate formation process to shadow evaporation or to macroscopic contacts formed by probes. Here we report on a new dry transfer process which allows the transistor to be placed on top of the PEO and the doping to be field-controlled by the substrate back gate. In this paper we show the transfer process and characteristics of the ion motion and conductivity modulation under field-control.
The dry transfer process is illustrated in Fig. 1. To create the top portion of the device, source and drain contacts are patterned onto wide area graphene formed by chemical vapor deposition. Polyisobutylene (PIB) and a PDMS stamp are then applied as handling layers (Fig. 1b). The Cu substrate is then etched in ammonium persulfate (APS) and the top portion is joined to the bottom (Fig. 1e). We have fabricated devices with both Au and graphene backgates, and initial tests were performed with an Au backgate, patterned into stripes to minimize leakage current through the electrolyte (Fig. 2).
Doping in the graphene channel is controlled by the backgate voltage (Vbg
). The conductivity, monitored by the drain current, (Id
), is varied by a factor of four by sweeping Vbg
at 0.5 V/s from −10 to 10 V (Fig. 3). The shift of the current minima (Dirac points) from zero are a direct measure of the ion doping of the graphene channel.
To characterize the retention of electrostatic doping, a 5 V backgate pulse is applied for 1 second and removed for 10 seconds while monitoring the drain current (Fig. 4). The current decreases by ~10% as the ions are polarized and then released.

Acknowledgements: This work was supported in part by the Center for Low Energy Systems Technology (LEAST), one of the six SRC STARnet Centers, sponsored by MARCO and DARPA.
[1] C. Lu et al. Nano Lett.
4, pp. 623–627 (2004)
[2] A. Das et al., Nat. Nanotech, 3, pp. 201-215 (2008)
[3] D. Efetov and P. Kim, Phys. Rev. Lett.,
105, pp. 256805 (2010)
[4] M. Lin, et al., J. Phys. D, 45, 345102 (2012).
Electrochemical Synthesis of Graphene-Metal Oxide Heterostructure for Resistive Random Access Memory
Authors: Park MiSeok , Hong Kyung-Sik , Ahn SooHoon , Kwon HyukSang 
Published: February 2020

Graphene has a lot of merits for many engineering applications due to its unique physical, electrical and chemical properties [1-2]. Recently, a soft chemical reduction process of graphene oxide has been reported as a very efficient and safe method to fabricate a pure graphene film [3]. Also, the graphene-metal hybrids are fabricated by electrochemical methods in aqueous solution [4]. However, in spite of aforementioned enormous interests and efforts, the reduction mechanisms of graphene oxide and graphene-metal hybrid during electro-deposition are still unclear and controversial.
In this study, the electrochemical characteristics of reduction phenomena of graphene oxide and graphen-metal oxide hybrids are investigated in detail. To investigate the exact reduction potential of graphene oxide and a variety of graphene-metal oxide hybrids in aqueous solution, the electrochemical analyses are accompanied by a cyclic voltammetry. The graphene-metal oxide hybrid film was electrochemically deposited on the conductive substrates using the cyclic co-electrodeposition method.
Furthermore, we have confirmed that the electrochemically formed hybrid film could be used for a Resistive Random Access Memory(RRAM) device through the test of resistive switching behavior of this hybrid films. This novel fabrication method of switching layer will provide several advantages for nonvolatile memory, such as low-power consumption, fast switching speed, and more simple and safe fabrication process.

References

[1] A. K. Geim, K. S. Novoselov, Nature Mater., 6, 183-191 (2007)
[2] H. Y. Jeong, and et al., Nano Lett., 10, 4381-4386 (2010).
[3] S. Stankovich, D. A. Dikin, R. S. Ruoff, et al., Carbon, 45, 1338-1565 (2007).
[4] R. S. Sundaram, C. G. Navarro, K. Kern, et al., Adv. Mater., 20, 3050-3053 (2008).