Large scale, selective dispersion of long single-walled carbon nanotubes with high photoluminescence quantum yield by shear force mixing

Graf, Arko; Zakharko, Yuriy; Schießl, Stefan P.; Backes, Claudia; Pfohl, Moritz; Flavel, Benjamin S.; Zaumseil, Jana

doi:10.1016/j.carbon.2016.05.002

Cited by 179 publications

(321 citation statements)

References 41 publications

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“…These values are very close to the 0.8% quantum yield reported for SC-suspended (6,5) SWCNTs with average lengths matching our sample. 20 A more recent study found lower quantum yields of only 0.2% for (6,5) SWCNTs purified by gel chromatography and DGU but suspended in aqueous SDS, 21 which is known to give weaker SWCNT emission than SC. 22 To check the pattern in our quantum yield results, we made a set of independent measurements using variance spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

Assessing Inhomogeneity in Sorted Samples of Single-Walled Carbon Nanotubes through Fluorescence and Variance Spectroscopy

Kadria-Vili¹,

Sanchez²,

Bachilo³

et al. 2017

ECS J. Solid State Sci. Technol.

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Detailed spectroscopic analysis has been used to study the homogeneity of single-walled carbon nanotube fractions carefully prepared by nonlinear density gradient ultracentrifugation sorting. Two distinct colored bands containing (6,5) enantiomers were subdivided into several extracted fractions that were separately diluted with sodium cholate surfactant and characterized by fluorescence, absorption, and variance spectroscopy. Values were measured for emission and absorption peak positions, Stokes shifts, emission peak widths, and emissive quantum yields. In addition, variance data were used to find relative emission per nanotube and to plot covariance slices representing homogeneous emission spectra. It was found that emission from SWCNTs within the upper enantiomer band shifts to shorter wavelengths with increasing depth in the centrifuge tube. In the lower enantiomer band such spectral shifts were not observed, but the emissive quantum yields decreased with depth. Variance analysis revealed spectral differences among SWCNTs within the same fraction of the same band. It is concluded that current methods for density gradient ultracentrifugation sorting produce samples that retain measurable structural and spectral inhomogeneities. Single-walled carbon nanotubes (SWCNTs) are probably the best known and most intensely studied artificial nanomaterial. For some purposes, SWCNTs may be viewed as a single substance because all of them are tubular structures formed from covalently bonded, sp 2 -hybridized carbon atoms. However, every SWCNT has a specific crystalline structure defining a particular diameter and roll-up angle. 1Each such structural species is uniquely labeled by a pair of integers, (n,m), that designate how a graphene sheet can be rolled up to generate that SWCNT. In addition to having specific physical structures, the different (n,m) species also display distinct vibrational frequencies, electronic energy levels, transport properties, optical spectra, strain energies, redox potentials, and chemical reactivities. They should therefore be considered separate chemical substances.Unfortunately, all current methods for growing SWCNTs in practical quantities produce a range of (n,m) structures and thus give samples with highly inhomogeneous properties. Such mixtures are less useful for many refined applications and also pose challenges in basic research studies. The sorting of mixed SWCNT samples into structurally pure fractions is therefore a major goal of the field. Purification involves not only fractionation by (n,m) structure, but also the separation of individualized from aggregated SWCNTs and the removal of residual catalyst particles, amorphous carbon, and perhaps double-or multi-walled nanotubes. In addition, some sorting methods can separate the left-and right-handed enantiomeric forms of chiral SWCNTs and the water-filled from the empty forms of (n,m) species. 2-6Methods for reducing the extensive inhomogeneity of SWCNT samples must be supported by powerful characterization tools to guide and asse...

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Section: Resultsmentioning

confidence: 99%

Assessing Inhomogeneity in Sorted Samples of Single-Walled Carbon Nanotubes through Fluorescence and Variance Spectroscopy

Kadria-Vili¹,

Sanchez²,

Bachilo³

et al. 2017

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…[66] A wide variety of cationic (e.g., CTAB), anionic (e.g., cholates and alkylsulfonates) and nonionic (e.g., Triton X-100) [67] surfactants as well as various versions of natural and synthetic DNA [68] have been used to produce aqueous dispersions of SWCNTs, while conjugated polymers are primarily used for the dispersion of nanotubes in organic solvents (e.g., toluene). [34] Monochiral SWCNT dispersions reveal the true colors of different carbon nanotube species as shown in Figure 4b for (6,5) (purple) and (7,5) (green) SWCNTs. [72] The dispersion of SWCNTs with suitable π-conjugated polymers offers the advantage of separation and colloidal stabilization in a single step through selective polymer wrapping.…”

Section: Solutions and Dispersionsmentioning

confidence: 94%

“…The optical properties (absorption/emission wavelength) of semiconducting polymers are not so strongly affected by M n , once the conjugation length is exceeded, which is typically just a few monomer units. [34,37] The length distribution can be measured by statistical atomic force microscopy, via bulk viscosity measurements, [38] analytical ultracentrifugation (AUC) [39] or by optically determining the diffusion constant of many individual nanotubes. This also means that the overall length and end-groups of a polymer are not particularly important.…”

Section: Length Distribution and Molar Weightmentioning

confidence: 99%

“…Typical length values for nanotubes in dispersion range from less than hundred nanometers to several micrometers. [34] Copyright 2016, Elsevier. The average length of an SWCNT sample predominantly depends on the dispersion method.…”

Section: Length Distribution and Molar Weightmentioning

confidence: 99%

“…[125] The resulting bound electron-hole pairs can even be categorized as Frenkel excitons due to their large binding energies (few hundred meV) and relatively small size (few nm). [34,128,129] For detailed reviews on this topic see, for example, Miyauchi et al [130] and Amori et al [131] The bright exciton is responsible for the strong E 11 absorption and emission peak in Figure 6a. [12] Since there are two carbon atoms in a unit cell of graphene, there are two equivalent valleys (K and K′) resulting in 16 possible excitonic states for carbon nanotubes: 4 singlet and 12 triplet excitons.…”

Section: Absorption and Emissionmentioning

confidence: 99%

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Semiconducting Single‐Walled Carbon Nanotubes or Very Rigid Conjugated Polymers: A Comparison

Zaumseil

2018

Adv Elect Materials

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With the ability to produce large amounts of purely semiconducting and even monochiral dispersions of single-walled carbon nanotubes (SWCNT) their application as a bulk material in thin film devices on a large scale becomes feasible. Their physical properties, processing, and final devices are quite similar to those of semiconducting polymers. In the extreme case one may view carbon nanotubes as very long, rigid, and fully conjugated polymers. This analogy raises the question whether the knowledge accumulated over the last two decades of processing and studying conjugated polymers could be transferred to solution-processed nanotube devices. Here, the optical and electronic properties of both materials in solution and in thin films are discussed and compared with a focus on their application in optoelectronic devices. Some striking similarities and common issues are highlighted to show the connection between conjugated polymers and SWCNTs as 1D semiconductors.

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Recent Developments and Novel Applications of Thin Film, Light‐Emitting Transistors

Zaumseil

2019

Adv Funct Materials

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Light-emitting field-effect transistors (LEFETs) combine switching and amplification with light emission and thus represent an interesting optoelectronic device. They are not limited anymore to a few examples and specific materials but are nearly universal for a wide range of semiconductors, from organic to inorganic and nanoscale. This review introduces the basic working principles of lateral unipolar and ambipolar LEFETs and discusses recent examples based on various solution-processed semiconducting materials. Applications beyond simple light emission are presented and possible future directions for lightemitting transistors with added functionalities are outlined. The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201905269.thus excluding vertical LEFETs, which have been demonstrated for some organic emitter systems. [5][6][7] We will start with LEFETs that do not rely on the injection of both holes and electrons in a single semiconducting layer but show unipolar charge transport and may include multiple semiconducting layers. This short section will be followed by an overview of truly ambipolar single-layer LEFETs, the different possible working principles and various emissive semiconductors with their advantages and drawbacks. The review will conclude with recent examples of LEFET applications that go beyond simple light-emission and take advantage of specific device properties to add functionalities that are difficult to achieve with other optoelectronic devices.

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Large scale, selective dispersion of long single-walled carbon nanotubes with high photoluminescence quantum yield by shear force mixing

Cited by 179 publications

References 41 publications

Assessing Inhomogeneity in Sorted Samples of Single-Walled Carbon Nanotubes through Fluorescence and Variance Spectroscopy

Assessing Inhomogeneity in Sorted Samples of Single-Walled Carbon Nanotubes through Fluorescence and Variance Spectroscopy

Semiconducting Single‐Walled Carbon Nanotubes or Very Rigid Conjugated Polymers: A Comparison

Recent Developments and Novel Applications of Thin Film, Light‐Emitting Transistors

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