Optical Properties Of Carbon Nanotubes Research Articles

(Invited) Macroscopically Aligned Carbon Nanotubes for Photonics, Electronics, and Thermoelectrics

The remarkable flexibility, stable chemical structure, and extraordinary thermal, electrical, and optical properties of carbon nanotubes (CNTs) are promising for a variety of applications in flexible and/or high-temperature electronics, optoelectronics, and thermoelectrics, including wearables, refractory photonics, and waste heat harvesting. However, the long-standing goal in the preparation of CNT ensembles is how to maintain the extraordinary properties of individual CNTs on a macroscopic scale. The polydispersity and randomness remain two main challenges. Here, we will discuss different methods for creating macroscopically aligned CNTs, including spontaneous formation of wafer-scale aligned CNT films via controlled vacuum filtration and production of ultrahigh-conductivity CNT fibers and films through solution spinning and coating. We will then describe the optical, dc and ac electrical, thermal, and thermoelectric properties of these materials. These results are promising for device applications in various fields such as flexible CNT broadband detectors, spectrally selective thermal emitters, and thermoelectric devices.

Overlapping of linear optical spectra in metallic carbon nanotubes, Controlled by applied axial magnetic field and uniaxial strain

The excitons and absorption spectra of M11 and M22 transitions in metallic carbon nanotubes were calculated by the tight-binding model, under the combined effect of axial magnetic field and uniaxial strain. It is interesting to find that the separated absorption peaks induced by axial magnetic field will meet each other when the uniaxial strain is applied. At the same axial magnetic field, the first overlapping point is appeared for Mii−−2 and Mii+−1 exciton with small uniaxial strain, and the biggest uniaxial strain is needed for Mii−−1 and Mii+−2 exciton. When we change the magnitude of the axial magnetic field, the overlapping point displays different variation trend for four separate excitons. This overlapping phenomenon is also occurred for other metallic tubes: with bigger diameter, smaller uniaxial strain is needed. More important is that an useful tool is offered to regulate the optical properties of carbon nanotubes by applying simultaneously the axial magnetic field and uniaxial strain.

Carbon nanotube production from algal biochar using microwave irradiation technology

In this study, we evaluated the transformation of algal-based biochar into carbon nanotubes by irradiation in a microwave oven at low energies (100–300 W). Three species of algae (Macrocystis pyrifera, Sarcothalia crispata, and Scenedesmus almeriensis) were selected and pyrolyzed to obtain biochar for carbon nanotubes (CNTs) growth in the presence of ferrocene as the catalyst. The CNTs obtained were characterized by dynamic light scattering, UVVIS spectroscopy, Raman spectroscopy, transmission electron microscopy, X-ray diffraction, and electrical conductivity. The results indicate that algal biochar can be used for CNT growth. The heterogeneous structure of algal biochar can initiate the graphitization process for the formation of CNTs. The characteristics of synthesized CNTs vary with the biochar source used as a precursor. Thus, both the degree of graphitization of the wall and the content of nanotubes were higher using biochar with higher carbon content (from microalga Scenedesmus almeriensis); otherwise, the hydrodynamic diameter and electrical conductivity were higher using biochar with upper mineral ash content (from microalga Macrocystis pyrifera). Furthermore, it was found that a low catalyst concentration was required to promote growth due to the reactivity of the mineral ash of the biochar, and it was demonstrated that microwave heating conditions, such as microwave power and temperature, lead to variations in the optical properties of CNTs, such as the band gap energy, CNTs content, and measurement of the size such as the hydrodynamic diameter.

(Invited, Digital Presentation) Macroscopically Aligned Carbon Nanotubes for Photonics, Electronics, and Thermoelectrics

The remarkable flexibility, stable chemical structure, and extraordinary thermal, electrical, and optical properties of carbon nanotubes (CNTs) are promising for a variety of applications in flexible and/or high-temperature electronics, optoelectronics, and thermoelectrics, including wearables, refractory photonics, and waste heat harvesting [1]. However, the long-standing goal in the preparation of CNT ensembles is how to maintain the extraordinary properties of individual CNTs on a macroscopic scale. The polydispersity and randomness remain two main challenges.Here, we will discuss different methods for creating macroscopically aligned CNTs, including spontaneous formation of wafer-scale aligned CNT films via controlled vacuum filtration [2-4] and production of ultrahigh-conductivity CNT fibers and films through solution spinning and coating [5,6]. We will then describe the optical [2,7-11], dc and ac electrical [2,12-17], thermal [18], and thermoelectric [19-21] properties of these materials. These results are promising for device applications in various fields such as flexible CNT broadband detectors [22-26], spectrally selective thermal emitters [11], and thermoelectric devices [20,21]. W. Gao et al., “Macroscopically Aligned Carbon Nanotubes for Flexible and High-Temperature Electronics, Optoelectronics, and Thermoelectrics,” Journal of Physics D: Applied Physics 53, 063001 (2020).X. He et al., “Wafer-Scale Monodomain Films of Spontaneously Aligned Single-Walled Carbon Nanotubes,” Nature Nanotechnology 11, 633 (2016).W. Gao and J. Kono, “Science and Applications of Wafer-Scale Crystalline Carbon Nanotube Films Prepared through Controlled Vacuum Filtration,” Royal Society Open Science 6, 181605 (2019).N. Komatsu et al., “Groove-Assisted Global Spontaneous Alignment of Carbon Nanotubes in Vacuum Filtration,” Nano Letters 20, 2332 (2020).N. Behabtu et al., “Strong, Light, Multifunctional Fibers of Carbon Nanotubes with Ultrahigh Conductivity,” Science 339, 182 (2013).L. W. Taylor et al., “Improved Properties, Increased Production, and the Path to Broad Adoption of Carbon Nanotube Fibers,” Carbon 171, 689 (2021).K. Yanagi et al., “Intersubband Plasmons in the Quantum Limit in Gated and Aligned Carbon Nanotubes,” Nature Communications 9, 1121 (2018).W. Gao et al., “Continuous Transition between Weak and Ultrastrong Coupling through Exceptional Points in Carbon Nanotube Microcavity Exciton–Polaritons,” Nature Photonics 12, 362 (2018).M. E. Green et al., “Bright and Ultrafast Photoelectron Emission from Aligned Single-Wall Carbon Nanotubes through Multiphoton Exciton Resonance,” Nano Letters 19, 158 (2019).F. Katsutani et al., “Direct Observation of Cross-Polarized Excitons in Aligned Single-Chirality Single-Wall Carbon Nanotubes,” Physical Review B 99, 035426 (2019).W. Gao et al., “Macroscopically Aligned Carbon Nanotubes as a Refractory Platform for Hyperbolic Thermal Emitters,” ACS Photonics 6, 1602 (2019).X. Wang et al., “High-Ampacity Power Cables of Tightly-Packed and Aligned Carbon Nanotubes,” Advanced Functional Materials 24, 3241 (2014).A. Zubair et al., “Carbon Nanotube Fiber Terahertz Polarizer,” Applied Physics Letters 108, 141107 (2016).D. Tristant et al., “Enlightening the Ultrahigh Electrical Conductivities of Doped Double-Wall Carbon Nanotube Fibers by Raman Spectroscopy and First-Principles Calculations,” Nanoscale 18, 19668 (2016).N. Komatsu et al., “Modulation-Doped Multiple Quantum Wells of Aligned Single-Wall Carbon Nanotubes,” Advanced Functional Materials 27, 1606022 (2017).F. R. G. Bagsican et al., “Terahertz Excitonics in Carbon Nanotubes: Exciton Autoionization and Multiplication,” Nano Letters 20, 3098 (2020).A. Baydin et al., “Giant Terahertz Polarization Rotation in Ultrathin Films of Aligned Carbon Nanotubes,” Optica 8, 760 (2021).S. Yamaguchi et al., “One-Directional Thermal Transport in Densely Aligned Single-Wall Carbon Nanotube Films,” Applied Physics Letters 115, 223104 (2019).K. Fukuhara et al., “Isotropic Seebeck Coefficient of Aligned Single-Wall Carbon Nanotube Films,” Applied Physics Letters 113, 243105 (2018).Y. Ichinose et al., “Solving the Thermoelectric Trade-Off Problem with Metallic Carbon Nanotubes,” Nano Letters 19, 7370 (2019).N. Komatsu et al., “Macroscopic Weavable Fibers of Carbon Nanotubes with Giant Thermoelectric Power Factor,” Nature Communications 12, 4931 (2021).S. Nanot et al., “Broadband, Polarization-Sensitive Photodetector Based on Optically-Thick Films of Macroscopically Long, Dense, and Aligned Carbon Nanotubes,” Scientific Reports 3, 1335 (2013).X. He et al., “Photothermoelectric p-n Junction Photodetector with Intrinsic Broadband Polarimetry Based on Macroscopic Carbon Nanotube Films,” ACS Nano 7, 7271 (2013).X. He et al., “Carbon Nanotube Terahertz Detector,” Nano Letters 14, 3953 (2014).X. He, F. Léonard, and J. Kono, “Uncooled Carbon Nanotube Photodetectors,” Advanced Optical Materials 3, 989 (2015).A. Zubair et al., “Carbon Nanotube Woven Textile Photodetector,” Physical Review Materials 2, 015201 (2018).

Methotrexate detection based on the optical properties of carbon nanotubes and silver nano particles nanocomposites

Methotrexate detection based on the optical properties of carbon nanotubes and silver nano particles nanocomposites

(Invited) Mechanistic Study of the Covalent Bond-Mediated Charge Transfer between Carbon Nanotubes and Molecular Probes

The noncovalent interaction between carbon nanotubes and molecular groups leads to hybrid systems with low stability and poorly defined structure in terms of the density of functional groups, their relative positions and orientation. Since these factors are affected by microenvironmental parameters, studying the charge transfer of such dynamic systems is challenging. Covalent attachment of molecular probes, on the other hand, disturb the π-conjugated integrity of carbon nanotubes and suppress their light emission1,2. In 2017, we explored a nondestructive covalent functionalization (NCF) that opens up new avenues to overcome the aforementioned challenges3. NCF is an effective strategy for the preparation of stable carbon nanotube hybrids with defined functionality and preserved photoluminescence property4. In this work, we have used NCF for the mechanistic study of covalent bond-mediated charge transfer between molecular probes and carbon nanotubes by manipulating the structure of the probes. Different molecular probes with the same backbone but different functionality were synthesized by reaction between aniline derivatives and cyanuric chloride (Figure 1a). The conjugation of the molecular probes to the surface of carbon nanotubes by nitrene [2+1] cycloaddition reaction resulted in hybrid systems with the preserved physicochemical properties. π conjugated system of carbon nanotubes was integrated outwards into the backbone of molecular probes upon opening the aziridine ring in the bridge position and resulted in charge transfer between these two components (Figure 1b). Due to the same chemical backbone but different number of electron donating groups, variation in the optical properties of carbon nanotubes was assigned to the contribution of these groups in doping through which a mechanism for the covalent bond-mediated charge transfer was proposed. As a proof of concept, we have demonstrated a new way to forward the π conjugated system of carbon nanotubes outwards into other (macro)molecules which results in new systems with the unique optoelectronic properties. References Cognet, L. et al. Science 2007, 316, 1465.Piao, Y. et al. Chem. 2013, 5, 840.Setaro et al. Nat Commun. 2017, 8, 14281.Godin et al. Science Advances, 2019, 5, eaax116. Figure 1

Study of uniformly doped nano scale single-walled CNTFET under dark and illuminated conditions

Advancement in technology has resulted in transistors scaling down to nanometers. The evolution has resulted in investigations which extend to the structure of nanometer devices and the theories related to them. The extent of the investigation has stepped into Single-walled carbon nanotube field effect transistor (SW-CNTFET). The numerical method of self-consistent 3D Poisson and Schrödinger equations is solved by the Leibmann's iteration method. Further, study the effect of illumination on different parameters including the surface potential, drain current, mobility, transconductance and sub-threshold of n-type SW- CNTFET with high-k gate dielectric constant. Finding is that the use of Hfo2 high-k dielectric enhances the device characteristics. Comparing the drain current in illumination and dark condition, there is a notable increase when illuminated. The simulated results of proposed CNTFET photo detector were compared with existing MOSFET photo detector. Better drain current, transconductance and cut off frequency were obtained for the CNTFET. This result is in very much agreement with results obtained from numerical simulations. These findings on optical properties of carbon nanotubes (CNTFET) are sure to advance the fields of photo detectors, OEIC, solar cells and IC fabrications.

(Invited) Optical Properties of Graphene Nanoribbons and Quantum Dots

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].

A comprehensive study on electronic structure and optical properties of carbon nanotubes with doped B, Al, Ga, Si, Ge, N, P and As and different diameters

Density functional theory (DFT) is used for investigating the electronic structure and optical properties carbon nanotubes (CNTs) with doped B, Al, Ga, Si, Ge, N, P and As and different diameters. Our results show that the stability of CNTs increased when it comes to an increase in diameter, however, stability decreases depending on doping additives to pure CNTs. B-doped CNTs are the most effective for electronic conductivity due to its lower band gap. The non-linear optical (NLO) properties are discussed according to dipole moment, polarizability, and hyperpolarizability. All the doped CNTs exhibit a good NLO activity. B-, Al-, Ga- and N-doped CNTs have a significant effect on NLO properties. The band gap of CNTs considerably decreased from 2.76 eV to 1.40 eV and 1.78 eV–0.83 eV based on the diameter. The reactivity properties investigated based on chemical hardness, softness, and potential, electronegativity, electrophilicity, the maximum amount of electronic charge index, the electron accepting and donating capability as well as electronic density of states are also presented and analyzed. Herein, the results indicated that the characteristic properties of CNTs can be controlled with different atoms doped CNTs and diameters.

Controlling the optical properties of carbon nanotubes with organic colour-centre quantum defects.

Previously unwelcome, defects are emerging as a new frontier of research, providing a molecular focal point to study the coupling of electrons, excitons, phonons and spin in low-dimensional materials. This opportunity is particularly intriguing in semiconducting single-walled carbon nanotubes, in which covalently bonding organic functional groups to the sp 2 carbon lattice can produce tunable sp 3 quantum defects that fluoresce brightly in the shortwave IR, emitting pure single photons at room temperature. These novel physical properties have made such synthetic defects, or 'organic colour centres', exciting new systems for chemistry, physics, materials science, engineering and quantum technologies. This Review examines progress in this emerging field and presents a unified description of this new family of quantum emitters, as well as providing an outlook of the rapidly expanding research and applications of synthetic defects.

Improving steam generation and distilled water production by volumetric solar heating

The ability of the nanofluids in absorption the solar radiation and steam generation has attracted considerable attentions in recent years. The purpose of the present study is to examine the optical properties of carbon nanotubes for application in solar steam generation and distilled water production. Accordingly, three types of carbon nanotubes were selected including single-wall and functionalized multi-wall carbon nanotubes (by carboxyl and hydroxyl groups). The evaporation performances of all three carbon nanotubes are evaluated at light intensities up to 3.5 kW/m2 using a solar simulator. Furthermore, a distillation system was constructed to analyze the effects of nanoparticle type, concentration and light intensity on water production. The results indicated that the nanofluid containing the multi-wall carbon nanotube functionalized by hydroxyl group (MWCNT-OH) presents more promising optical and stability properties, with higher evaporation rates as compared to the other nanoparticles. Adding this nanoparticle cuts the beginning of water production in half and enhances the evaporation rate and water production efficiency about 3 times larger than pure water at 3.5 kW/m2 light intensity., The results for the mentioned nanofluid (MWCNT-OH) also revealed that the mass concentration increase from 0.0005% to 0.002% increases the evaporation rate and, ultimately, the distilled water production by about 46.2%. Finally, the cost analysis of the water production for all considered nanoparticles has been performed and compared.

Strong Electrochemiluminescence Emission from Oxidized Multiwalled Carbon Nanotubes

Carbon nanotubes (CNTs) as well-known nanomaterials are extensively studied and widely applied in various fields. Nitric acid (HNO3 ) is often used to treat CNTs for purification purposes and preparing oxidized CNTs for various applications. However, too little attention is paid to investigating the effect of HNO3 treatment on the optical properties of CNTs. In this work, it is observed for the first time that HNO3 -oxidized multiwalled carbon nanotubes (ox-MWCNTs) have strong electrochemiluminescence (ECL) activity, which enables ox-MWCNTs to become new and good ECL carbon nanomaterials after carbon quantum dots (CQDs) and graphene quantum dots (GQDs). Various characterization technologies, such as transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy, are used to reveal the relationship between ECL activity and surface states. The ECL behaviors of ox-MWCNTs are investigated in detail and a possible ECL mechanism is proposed. Finally, the new ECL nanomaterials of ox-MWCNTs are envisioned to have promising applications in sensitive ECL sensing and in the study of CNT-based catalysts.

Optical properties of semiconducting zigzag carbon nanotubes with and without defects.

The excited states of a series of semiconducting zigzag (n, 0) tubes are studied using the GW method and the Bethe-Salpeter equation within the ab initio many-body perturbation theory. The optical variation rule of the excitation energy with the tube diameter exhibits a family pattern, which arises from the electronic structure of the pristine tube and depends on the value of n mod 3. The introduction of single vacancy and Stone-Wales defects with different orientations affords an effective route for modulating the band structures and optical spectra, resulting in the variation of the selection rules of the excitons and turning dipole-forbidden excitons into dipole-allowed ones. The new localized impurity states in defected tubes will provide additional optically allowed transitions and give rise to pronounced satellite red-shifted peaks. These findings provide inspiration for the tune of optical properties of carbon nanotubes in the future for applications in optoelectronics.

A contemporary review of optical properties of carbon nanotubes and graphene

Carbon nanotubes and graphene remain the best options for short-pulse fiber lasers.

Temperature and carrier density dependence of electron effective mass and bandgap in semiconductor carbon nanotubes at elevated temperature: Analytical calculations

The effects of temperature and carrier density on the self-energy of electrons in semiconductor carbon nanotubes (CNTs) are theoretically studied by using the Matsubara Green’s function approach. We show that the bandgap is slightly changed whereas the electron effective mass is strongly affected by the temperature and electron density. Furthermore, an interesting discrepancy between the results obtained from the screening dynamical approximation and that from the Hartree-Fock approximation is shown. Specifically, the calculated quantities are compared to the results obtained in a recent experiment, and a good agreement for the energy shift is seen. These results could help to clarify the role of the Coulomb interaction and the correlation and exchange energy on the optical properties of CNTs in a wide range of temperature and density.

Optical properties of carbon nanotubes with Haeckelite structure under a transverse electric field: Density functional theory

Optical properties of Haeckelite structure as well as pristine carbon nanotubes were studied. Density functional theory was used to analyze optical absorption, reflectivity, dielectric function, conductivity, refractive index and loss function under transverse electric field. Our results show significant variations between pristine and Haeckelite structure nanotubes. For instance, we found that introducing transverse electric field has direct impact on the static values of dielectric function real part. Furthermore, the static refractive indices record a significant increase upon introducing R57 and H567 Haeckelite structures to pristine nanotube at any nature of the incident light. Additionally, all real part of the optical conductivity spectra are red shifted regardless the incident light nature and the defect types introduced to pristine nanotube. Besides, the peak intensity of the imaginary part of the optical conductivity significantly decreases upon applying transverse electric field regardless the incident light nature.

Carbon Nanotube-Based Sensors for Early Cancer Detection

The early detection of cancer could lead to vastly improved patient outcomes. We aim to identify cancer biomarkers within the body at early disease stages, permitting detection before symptoms arise. We are developing implantable nanosensors, using the unique optical properties of carbon nanotubes, to facilitate non-invasive detection via optical detection through living tissues. The sensors could enable early detection of cancer in people at high risk for the disease, in successfully treated patients to monitor recurrence, or in patients who are undergoing treatment to inform clinical decisions.

(Invited) Functionalization of Carbon Nanotubes in a Micellar Environment

A key issue for applications of colloidal nanoobjects is related to their solubility in water. Indeed, their aggregation results in the deterioration of their intrinsic properties. In order to solve this problem, many strategies have been developed. As far as carbon nanotubes are concerned, the best way to solubilize them in water while preserving their outstanding properties is to use a micellar environment. As a consequence the chemistry of carbon nanotubes in micelles is a growing field of research. For instance, people have grafted photoswitches on the wall of nanotubes, have doped nanotubes with diazonium and even performed polymerization in micelles [1-4]. In this presentation, we will present our recent results on the functionalization of carbon nanotubes with different kind of molecules in a micellar environment (porphyrins [5, 6], polymers [7]…). In particular, we will focus on the influence of the molecules on the optical properties of carbon nanotubes both on ensemble and at the single object level.

An Analytical Approach to Model the Optical Properties of Carbon Nanotubes for Plasmonic Devices

An Analytical Approach to Model the Optical Properties of Carbon Nanotubes for Plasmonic Devices

Preparation, characterization, Raman, and terahertz spectroscopy study on carbon nanotubes, graphene nano-sheets, and onion like carbon materials

We present the optical properties of carbon nanotubes, graphene nanosheets, and onion like carbon (OLC) samples with different cages size in wide frequency range from 0.06 to 1650 THz. The samples were characterized by high resolution transmission electron microscope (HRTEM), Raman, and UV–Vis-IR-THz spectroscopy. The broad absorption bands centered at around 10, 3, 2.5, 1.5, and 1.8 THz for SWCNTs, MWCNTs, graphene nanosheets, large cages (OLC1), and small cages (OLC2) samples, respectively, are assigned to plasmon resonance due to the localization of free carriers in a finite length. For SWCNTs, both the plasmon band position and the Drude weight (D) are located at higher values as compared with MWCNTs, graphene nanosheets, and OLC sample, suggesting that the dimensionality of the system plays a major role regarding the carrier mobility of the graphene structure. The differences in the estimated values of D, the Fermi energy (Ef), and density of carriers (N) in case of OLC samples can be due to the variation in sizes of the cages and the variation of the defects in the structure of the outermost layers of cages, where each cages consist of multi-layers of graphene enclosed one into another.