bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectral Inhomogeneities in Swcnts Sorted By Nonlinear Dgu
Authors: Kadria-Vili Yara , Sanchez Stephen R. , Bachilo Sergei M. , Weisman R. Bruce 
Published: February 2020

Single-walled nanotubes are widely studied nanomaterials because of their unusual properties and potential applications. Unfortunately all practical current growth methods produce nanotubes with a variety of (n,m) structures and therefore physical properties. This inhomogeneity hinders some studies and applications in which samples with a single structure or a narrow range of structures are needed. To date, a number of sorting methods have been introduced to separate single-walled from multi-walled nanotubes, individualized from aggregated, metallic from semiconducting, water-filled from empty, and even right-handed from left-handed forms of the same (n,m) SWCNT species. Nonlinear density gradient ultracentrifugation (nDGU) separation has been shown to be one of the most selective tools for preparing high purity SWCNT samples. However, there has been little study of whether nDGU fractions actually are highly homogeneous. We have analyzed such fractions and find that layers containing enantiomers of individual (n,m) species show unexpected spectral inhomogeneities.
Each enantiomeric layer of (6,5) SWCNTs was extracted into three or four 48 µL fractions using a custom-built high precision automated fractionator. These extracted fractions were analyzed for their fluorescence and absorption spectra. They were then diluted into sodium cholate solution to provide uniform coatings, and the spectral measurements were repeated along with determinations of their absolute fluorescence quantum yields and measurements of variance spectra. The undiluted fractions within a single layer showed significant differences in spectral peak position and line width. Dilution reduced these inhomogeneities and caused ca. 50 cm-1 blue shifts in E11 peak positions for the upper enantiomer band but only 5 cm-1 shifts for the lower one. Emission line widths were also decreased substantially and quantum yields increased by a factor of ca. 2. Nevertheless, the diluted fractions gave quantum yields of 0.8 ± 0.1% and varied by a factor of 1.5 within the lower layer. They reached a maximum of approximately 1%, which is similar to that for SWCNTs wrapped by PFO in toluene. Further insight was obtained from variance spectral data, which confirmed the differences in emission per nanotube within layers and revealed that the low frequency wing of the E11 emission band of each fraction results from inhomogeneous broadening. Our results show that even the use of a highly selective SWCNT sorting method may not ensure spectroscopic homogeneity within the separated samples.
Diameter Selective Chemical Doping of Semiconducting Single-Wall Carbon Nanotubes
Authors: Achsnich Melanie , Deutsch Marian , Muetzel Carina , Hertel Tobias 
Published: February 2020

Doping of semiconductors, such as single-wall carbon nanotubes (SWNTs), by the introduction or removal of charges can be used for modification of their electronic and optical structure. This offers unique opportunities for the fabrication of versatile materials with new properties. However, despite a broad body of work,1−3 the control and spectroscopic assessment of the doping of SWNTs is still being developed4,5 in order to be able to reproducibly tailor semiconductor properties.
Here, we have studied the photophysical properties of chemically doped SWNTs by absorption and photoluminescence spectroscopy. Polychiral samples of purified HiPCO soot were charged by oxidation with gold chloride. Thanks to very well-resolved and narrow exciton bands in these samples, the trionic signatures induced by charges could be resolved for up to five distinct nanotube species. An investigation of spectral changes in absorption measurements as a function of gold chloride concentration reveals that tubes with smaller bandgaps are doped at lower gold chloride concentrations. The trion binding energy with respect to the dipole-allowed first sub-band exciton transition was also found to increase systematically with decreasing diameter in agreement with previous findings.1,2 In addition, we find that SWNT oxidation potentials decrease nearly linearly with increasing nanotube diameter. Lastly, a surprisingly abrupt change of exciton oscillator strengths at redox potentials near the nanotube band edge provides evidence for band gap renormalization.

References

1. R. Matsunaga, K. Matsuda, Y. Kanemitsu, Phys. Rev. Lett. 2011, 106, 037404.
2. J. S. Park, Y. Hirana, S. Mouri, Y. Miyauchi, N. Nakashima, K. Matsuda, JACS
2012,
134, 14461−14466.
3. S. M. Santos, B. Yuma, S. Berciaud, J. Shaver, M. Gallart, P. Gilliot, L. Cognet, B. Lounis, Phys. Rev. Lett. 2011, 107, 187401.
4. H. Hartleb, F. Späth, T. Hertel, ACS Nano
2015, 9, 10461−10470.
5. M. Yoshida, A. Popert, Y. K. Kato, Phys. Rev. B
2016, 93, 041402.
(Invited) Probing Optical and Magneto-Optical Properties of Carbon Nanotubes Using Enriched Carbon Nanotube Materials
Authors: Haroz Erik H. 
Published: February 2020

Enriched carbon nanotubes materials, whether purified in electronic type, diameter, filling or even specific chirality, have deepened researchers' understanding of the fundamental optical properties of single-wall carbon nanotubes (SWCNTS). In particular, density gradient ultracentrifugation and aqueous two-phase extraction techniques have enabled the production of sizable aqueous suspensions and aligned films, allowing the interrogation of chiral-specific absorption, emission and scattering properties. In this talk, I will discuss two particular aspects: the chiral-specific nature of the Raman M-mode in small-diameter semiconducting SWNCTs and the large orbital magnetic susceptibility anisotropy of large-diameter metallic SWCNTs.
In the first part of the talk, I examine the unusual frequency dependence and excitation profile shape of the M-mode (~1620-1800 cm-1) in small-diameter semiconducting species such as the (5,4), (6,4), (8,3), (9,1), (6,5), (7,6), (11,0), (9,4) & (8,6). In particular, semiconducting species exhibit a mod- and diameter-dependent "fanning-out" behavior for E22 excitation, reminescent of that observed for optical transition energies. Even more interesting is the strongly asymmetrical excitation profile of the M-mode for a specific (n,m) species, deviating from the standard symmetrical profile observed for the radial breathing mode and the non-Condon-violating profile observed for the G-band. At certain energies in the excitation profile, the M-mode exceeded the G-band in intensity and unlike the G-band, the most intense peaks in the M-mode profile do not correspond to either the incoming or outgoing resonances. The M-mode seems to exhibit a new type of excitation profile shape.
In the second part of the talk, I discuss the magneto-optical properties of metallic SWCNTs. Using the strongly anisotropic optical and magnetic properties arising from the one-dimensional nature of carbon nanotubes, we aligned SWCNTs in aqueous suspension in magnetic fields up to 22T. Specifically, the orbital magnetic susceptibility anisotropy (Δχ) was measured, via magnetic linear dichroism spectroscopy enabled by the unique Florida Split-Helix magnet system, of multiple large-diameter metallic and semiconducting SWCNT species. In particular for the metallic species, Δχ’s on the order of 10-4 emu/mol, an order of magnitude larger than any Δχ measured previously for SWCNTs, were observed. Additionally, broadening and the beginnings of peak splitting of metallic optical absorption features, due to the Aharanov-Bohm effect, were also seen. The emergence of such magneto-optical behavior at such relatively “low” magnetic fields, combined with new developments in carbon nanotube sample preparation science, opens the door to observing new many-body effects through magneto-optics.
Lastly, I will share a few memories of my time with my friend and mentor, Robert Hauge.
(Invited) Massively Parallel, Aligned Arrays of Semiconducting Carbon Nanotubes for Realizing Field Effect Transistors with Current Density Exceeding Silicon and Gallium Arsenide
Authors: Arnold Michael S 
Published: February 2020

Calculations have indicated that aligned arrays of semiconducting carbon nanotubes (CNTs) promise to outperform conventional semiconducting materials in short-channel, aggressively scaled field effect transistors (FETs) like those used in semiconductor logic and high frequency amplifier technologies. These calculations have been based on extrapolation of measurements of FETs based on one CNT, in which ballistic transport approaching the quantum conductance limit of 2Go
=4e2/h has been achieved. However, constraints in CNT sorting, processing, alignment, and contacts give rise to non-idealities when CNTs are implemented in densely-packed parallel arrays, which has resulted in a conductance per CNT far from 2Go
. The consequence has been that it has been very difficult to create high performance CNT array FETs, and CNT array FETs have not outperformed but rather underperformed channel materials such as Si by 6x or more.
Here, we report nearly ballistic CNT array FETs at a density of 50 CNTs um-1, created via CNT sorting, wafer-scale alignment and assembly, and treatment. The on-state conductance in the arrays is as high as 0.46 Go
per CNT, and the conductance of the arrays reaches 1.7 mS um-1, which is 7x higher than previous state-of-the-art CNT array FETs made by other methods. The saturated on-state current density reaches 900 uA um-1 and is similar to or exceeds that of Si FETs when compared at equivalent gate oxide thickness, off-state current density, and channel length. The on-state current density exceeds that of GaAs FETs, as well. This leap in CNT FET array performance is a significant advance towards the exploitation of CNTs in high-performance semiconductor electronics technologies.

*Brady GJ, Way AJ, Safron NS, Evensen HT, Gopalan P, Arnold MS, Quasi-ballistic carbon nanotube array transistors with current density exceeding Si and GaAs, SCIENCE ADVANCES, 2 (9), e1601240 (2016)
Quantum Optical Studies on Diazonium Doped Carbon Nanotubes
Authors: He Xiaowei , Hartmann Nicolai F. , Ma Xuedan , Gao Weilu , Kono Junichiro , Blackburn Jeffrey L. , Htoon Han , Doorn Stephen K. 
Published: February 2020

The intentional incorporation of impurities and defects can serve as a powerful tool for modification of the electronic and optical properties of host nanomaterials and enabling of new functionalities1. Introduction of Sp3 defects by covalent functionalization to single-walled carbon nanotubes (SWCNTs) generates new emission states with energies lower than the optical bandgap (E11) of SWCNTs by 100 to 300 meV2. With controllable emission wavelengths and high quantum yield, these defect states open up new opportunities for the applications of SWCNTs in photonics such as lasing, photon upconversion and single photon emission3.
Recently, it has been shown that such doping sites are capable of emitting single photons at room-T, which opens the possibility of building room-T electrically-driven single photon emitters based on doped-SWCNTs. The realization of these devices needs the fine control of doping densities, to the point of introduction of solitary dopants on individual SWCNTs. It also requires the high emission quality from doping states, such as sharp linewidth of the emission spectra and non-blinking of the emission intensity.
In this work, we showed a chemical approach capable of creating solitary dopants on SWCNTs of different diameters. Our method was based on the fine control of the doping of surfactant-suspended and poly[9,9-dioctylfluorenyl-2,7-diyl] (PFO) wrapped SWCNTs by different diazonium salts. Quantum optical studies were performed on the diazonium doped-SWCNTs. We first investigated the photoluminescence (PL) spectra of doped-SWCNTs at room temperature and low temperature (4K). Individual, bright and stable emission peaks were observed from doped SWCNTs at room-T. The linewidth of the PL peaks decreased to 200 mirco-eV at 4K. Next, Hanbury Brown-Twiss (HBT) experiment was performed to explore the single photon nature of the emissions. Strong photon ant-bunching behavior with purity above 99% were observed on the doping emission peaks in the range of 1100-1400 nm at RT(295k).
[1] Piao, Yanmei. et al. Nature Chem. 2013, 5, 840.
[2] Hartmann, Nicolai F. et al. Nanoscale. 2015, 7,20521.
[3] Kim, Mijin. et al. J. Phys. Chem. C . 2016, 120, 11268.
[4] Ma, Xuedan. et al. Nature Nanotech. 2015, 10, 671.
(Invited) Optical Bistability in Air-Suspended Carbon Nanotubes
Authors: Kato Yuichiro K. 
Published: February 2020

Screening is limited in single-walled carbon nanotubes because of their one-dimensional nature, and the strong Coulomb interactions result in optical spectra dominated by excitons with binding energies lager than half an eV. Also because of the limited screening, a charged carrier can be bound to an exciton to form a trion that is stable at room temperature. In particular, air-suspended nanotubes exhibit pronounced effects because of reduced environmental screening [1,2], where adsorption and desorption of molecules on the surface of nanotubes can readily modulate such interactions.
Here we show that large screening effects on excitonic energies can cause laser-induced optical bistability [3]. Molecular desorption can occur with sufficient heating by laser, which in turn results in significant blueshift of exciton emission wavelength. When the excitation is detuned to a higher energy shoulder of the E22 absorption resonance, we observe abrupt transition and hysteretic behavior of emission wavelength in the excitation power dependence. We explain the bistability by simultaneous shifts of absorption and emission resonances, and perform time-resolved measurements to obtain relevant time scales.
Work supported by JSPS (KAKENHI JP26610080, JP16H05962), The Canon Foundation, and MEXT (Photon Frontier Network Program, Nanotechnology Platform).
[1] T. Uda, M. Yoshida, A. Ishii, Y. K. Kato, Nano Lett. 16, 2278 (2016).
[2] M. Yoshida, A. Popert, Y. K. Kato, Phys. Rev. B 93, 041402(R) (2016).
[3] T. Uda, A. Ishii, Y. K. Kato, in preparation.
(Invited) On the Theory of Nanotube-Graphene Crossiton: A New Class of Topological Solutions
Authors: Petrov Alexey G. , Rotkin Slava V. 
Published: February 2020

aIoffe Institute, 26 Polytekhnicheskaya, St. Petersburg, 194021, Russia

bDepartment of Physics, Department of Material Science; the Center for Advanced Materials & Nanotechnology and the Center for Photonics & Nanoelectronics, Lehigh University, Bethlehem, Pennsylvania 18015, United States
A problem of strong (aka non-perturbative) coupling between quantum systems has been in the focus of physics research for many decades, having both fundamental interest and value for applications from quantum information to spintronics. Most recently it received attention due to technological capability to couple electronic systems of different dimensionality, for example, one-dimensional (1d) to 2d-systems. Cross-dimensional excitation were shown here to form a new class of solutions of strongly coupled Hamiltonians.
We use the formalism of coupled Dyson equations, and propose an efficient method of obtaining a distinct family of non-perturbative solutions. It reproduces known ``polariton''-family in the limit of the same symmetry of the coupled systems. On contrary, when the symmetry of one system makes a sub-group of the other, and the coupling interaction preserves a sub-set of quantum numbers, like a wavevector along 1d-axis, a special class of solutions - crossiton - is found.
Green's functions (GF) of crossiton sub-modes can be expressed via GFs of uncoupled systems and interaction vertexes. The general crossiton Hamiltonian can be mapped on a wide range of quantum-mechanical problems (like Fano-Anderson problem) that, otherwise, are not obviously related. Such a solution, to the best of our knowledge, was not demonstrated before. We emphasize on that the problem is solved non-perturbatively, presenting full solution, beyond weak coupling model.
This research is supported by the NSF ECCS-1509786 (SVR) and RFBR 14-02-01223А (AGP).
Fig. 1. Bare (dashed) and renormalized (solid) GF of the crossiton in the 1d-system.

Figure 1
A Novel Multi-Sine Excitation Procedure for Impedance Spectroscopy Supports Automatic Drift Correction and Online Error Determination
Authors: Feihl Sebastian , Sholin Mark , Schiller Carl-Albrecht , Fröba Steffen , Multerer Michael , Strunz Werner 
Published: February 2020

The traditional way to measure impedance using single-sine (monochromatic) excitation is the most transparent and robust way to find reliable EIS data. Compared to the time saving polychromatic (i.e. multi-sine) excitation, the advantage of single-sine excitation is the unequivocal assignment of harmonic content in the response signal to unwanted interference. Systematic analysis of these harmonics allows for the determination of a reliable measurement variance for every single data sample immediately after raw data collection is complete. For decades, such a procedure named “Weighted Harmonics Autocorrelation” has proven its benefit for the EIS instruments of the authors group [1]. Another helpful feature is owed to the periodicity of the monochromatic excitation: unwanted time drift contributions can be calculated from succeeding periods of the response signal for the reconstruction of the drift-free response. This allows for an automatic drift correction [2].
These valuable features are hardly achievable using standard multi sine techniques. Here, even in the absence of interference, the response signals are neither periodic nor free of harmonics. In spite of the fact that monochromatic techniques have the better relationship between information density and time effort [3], it is sometimes preferable to use multi-sine whenever the total measurement time is crucial for practical reasons.
In this poster, a novel multi-sine excitation method will be presented that keeps the advantages of automatic drift correction and online error determination analogous to the monochromatic single-sine procedure.
Keywords: EIS, error determination, drift correction, multi-sine, single-sine
References:
[1] C.-A. Schiller, R. Kaus; Impedance Contributions Online 2008, 6, P4.1 - P4.13 http://accessimpedance.eu/images/stories/ICO6_P4.pdf
[2] C. A. Schiller, F. Richter, E. Gülzow, N. Wagner; J. Phys. Chem. Chem. Phys. 2001, 3, 374-378
[3] Ruben H. Milocco, Minimal measurement time in electrochemical impedance identification, Electrochim. Acta 1994, 39, 1433-1439
Multifunctional Electrospun Separators for Structural Battery Applications
Authors: Keaswejjareansuk Wisawat , Liang Jianyu 
Published: February 2020

Lithium-ion battery (LIB) has been utilized in variety applications as energy source. Structural battery is a new approach that employs multifunctional material concept to use LIB with load-bearing capability to minimize the weight of the complete energy consumption system and maximize the efficiency. Separators are polymeric materials that have been known as the weakest component of conventional LIB. This work aims at creating electrospun membranes with multifunction, improved thermal resistance and mechanical properties as the next generation LIB separator. Electrospinning process (ES) is known as simple, flexible, versatile also cost-effective at all scales. The ES employs an electrostatic force to control the production of nanofibers from polymer solutions. Solution and process parameters, such as type of polymer and cross-linking additives, concentration of polymer solution, acceleration voltage, and solution feed rate, have been studied to achieve the desirable membrane properties. Many characteristics of ES polymer membrane would affect performance of it as the separator in LIB. In this study, design of experiments techniques has also been utilized to optimize the parameters in creating an improved multifunctional separator for structural battery applications.
Understanding Performance Fade in High Energy Density Li Batteries
Authors: Dufek Eric J. , Nagpure Shrikant C , Wood Sean M , Dickerson Charles C , Tanim Tanvir , Liaw Bor Yann 
Published: February 2020

The desire to develop higher performing batteries can be linked with greater demand for long range electric vehicles, longer lasting consumer electronics, and increased use of energy storage technologies in applications such as grid storage. A key to enhancing battery energy density and specific energy for many of these applications is to reduce battery pack size while maintaining or even increasing total capacity. The first attempts at commercializing secondary Li metal batteries occurred over three decades ago.1,2 However, despite this long history there is still a significant gap between desired high energy density Li metal batteries and what can be effectively achieved.
One potential route to enhance energy density is the use of a high energy cathode such as nickel-rich lithium nickel manganese cobalt oxide (NMC) in conjunction with a liquid electrolyte and a Li metal negative electrode. In such a configuration, high theoretical energy densities of at least 500 Wh/kg can be realized with optimal utilization of active materials in both the positive and negative electrodes and minimized electrolyte volume.
With increased utilization of active materials, there is a respective decrease in volume of electrolyte and other non-active components such as conductive carbon and binder. Each of these reductions has the potential to shift the equilibrium of degradation processes and alter the accumulation of degradation byproducts in higher energy battery systems. This presentation will discuss some of the implications associated with this shift in degradation as the balance of materials transitions from having multiple components in excess to a more energy dense setting with minimal excesses.
1. Whittingham, M. S. History, Evolution, and Future Status of Energy Storage. Proc. IEEE
100, 1518–1534 (2012).
2. Brandt, K. Historical development of secondary lithium batteries. Solid State Ion.
69, 173–183 (1994).
Complex Hydride Solid-State Electrolytes for Li, Na and Mg Batteries
Authors: Kühnel Ruben-Simon , Yan Yigang , Duchêne Léo , Roedern Elsa , Cuervo Reyes Eduardo , Remhof Arndt , Battaglia Corsin 
Published: February 2020

The identification of a solid-state electrolyte that fulfills all the requirements to enable a competitive bulk-type all-solid-state battery remains a challenging task. The electrolyte should display high ionic conductivity, high thermal stability, good processability and importantly a large electrochemical stability window that ideally spans the redox potential of the conducted metal ion. Several electrolytes within the class of complex hydrides display such a favorable combination of battery relevant properties. Here, we will discuss our recent results for Li-, Na- and Mg-ion conductors.
We identified several compositions within the lithium-amide borohydride (Li(BH4)1-x
(NH2)
x
) system that display near room temperature conductivities of >6 mS/cm, comparable to the ones of typical carbonate-based liquid electrolytes used in commercial lithium-ion batteries. An Li4Ti5O12 half-cell based on such an electrolyte displays >60% capacity retention at 3.5 mA/cm2 (5C) and stable cycling for 400 cycles.[1] The mixed closo-borate Na2(B12H12)0.5(B10H10)0.5 displays a conductivity of 0.9 mS/cm at 20 °C, excellent thermal stability of up to 300 °C and an electrochemical stability window of 3 V that enables reversible plating of sodium.[2] We will also report on the preparation and characterization of magnesium ethylenediamine borohydride (Mg(en)1(BH4)2), which displays a very high conductivity of 6x10-5 S/cm at 70 °C for a magnesium-ion solid-state electrolyte.[3]
[1] Y. Yan, R.-S. Kühnel, A. Remhof, L. Duchêne, E. Cuervo Reyes, D. Rentsch, Z. Łodziana, C. Battaglia, Adv. Energy Mater., accepted.
[2] L. Duchêne, R.-S. Kühnel, D. Rentsch, A. Remhof, H. Hagemann, C. Battaglia, Chem. Commun. 2017, 53, 4195.
[3] E. Roedern, R.-S. Kühnel, A. Remhof, C. Battaglia, Sci. Rep. 2017, 7, 46189.