Download or read book Optical Properties of Single Walled Carbon Nanotubes written by HUALING. ZENG and published by . This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Properties of Single walled Carbon Nanotubes written by Ian Brooke Mortimer and published by . This book was released on 2007 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Optical Properties of Single walled Carbon Nanotubes written by Hermenegildo Nuno Pedrosa and published by . This book was released on 2006 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Properties of Single Walled Carbon Nanotubes written by Hualing Zeng and published by . This book was released on 2008 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Optical Properties of Single walled Carbon Nanotubes Separation Characterization and Measurement in Suspension written by Richard M. Russo and published by . This book was released on 2006 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The one dimensional structure of single-walled carbon nanotubes (SWNTs) gives rise to optical phenomena that differ from bulk materials. This dissertation studies the separation of SWNTs dissolved in aqueous media using surfactant molecules, and the measurement of their intrinsic optical properties including absorption and emission. The SWNTs were separated from the bundled form using mechanical processing techniques such as sonication and centrifugation. A processing study, which isolated the effects of sonication frequency, sonication power, and centrifugation speed, was performed to determine the factors that lead to the best separation. The results of this study suggest that the suspensions are a mixture of individual tubes and small bundles. Prior determinations of intrinsic nanotube properties based on the assumption of isolated nanotubes will have to be revisited. The transient absorption spectrum was measured for the S11 subband region using monochromatic pump excitation at wavelengths corresponding to S22 subband transitions, where the exciting pump fluence was sufficient to create many excitons on a single nanotube. The transient decay kinetics followed a linear dependence that was proportional to 1/ t on a log-log scale with a slope of -0.5, which is consistent with the diffusion limited recombination of excitons in one dimension. This result suggests that the decay of photoexcitations in nanotubes is initially governed by two-body kinetics, which becomes a one-body process only in the long time limit. Our work refutes the one-electron model for the excited state relaxation of nanotubes proposed by others. When the transient decay was studied as a function of the initial exciton population, the diffusion coefficient was found to be a different constant value at each initial population. Local thermalization of the surrounding medium may cause this difference, as thermal relaxation occurs on a time scale that is longer than that of exciton recombination in SWNTs. This work further elucidates the mechanism of excited state relaxation in SWNTs, and advances the understanding of one-dimensional nanostructures.
Download or read book Carbon nanotubes and graphene for photonic applications written by K. Matsuda and published by Elsevier Inc. Chapters. This book was released on 2013-08-31 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fundamental electronic states and optical properties of single-walled carbon nanotubes are briefly explained in this chapter. Moreover, the novel optical properties of carbon nanotubes revealed by advanced laser spectroscopy (single-nanotube spectroscopy and time-resolved spectroscopy) are introduced. Due to the enhanced Coulomb interaction, the optically generated electron-hole pair forms a strongly bound ‘exciton’ state, analogous to the hydrogen-like state in the carbon nanotubes. The striking features of excitons in the carbon nanotube, such as singlet-dark states and triplet states, which dominate the optical properties, are described in this chapter.
Download or read book Optical Properties of Individual and Bundled Single Walled Carbon Nanotubes written by MITCHELL. Anderson and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Properties of Doped Semiconducting Single Walled Carbon Nanotubes written by and published by . This book was released on 2009 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical and Thermo Optical Properties of Polyimide Single Walled Carbon Nanotube Films written by Joseph G. Smith and published by BiblioGov. This book was released on 2013-08 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The incorporation of single-walled carbon nanotubes (SWNTs) into the bulk of space environmentally durable polymers at loading levels greater than or equal to 0.05 wt % has afforded thin films with surface and volume resistivities sufficient for electrostatic charge mitigation. However, the optical transparency at 500 nm decreased and the thermo-optical properties (solar absorptivity and thermal emissivity) increased with increaed SWNT loading. These properties were also dependent on film thickness. The absorbance characteristics of the films as a function of SWNT loading and film thickness were measured and determined to follow the classical Beer-Lambert law. Based on these results, an empirical relationship was derived and molar absorptivities determined for both the SWNTs and polymer matrix to provide a predictive approximation of these properties. The molar absorptivity determined for SWNTs dispersed in the polymer was comparable to reported solution determined values for HiPco SWNTs.
Download or read book Effects of Chemical Environment on the Optical Properties of Single walled Carbon Nanotubes written by Wei-Chun Hung and published by . This book was released on 2011 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Next, the dispersion of SWNTs in Nafion aqueous system is sustainable in ethanol and in salt solutions for observing well-resolved NIR fluorescence peaks of SWNTs. The optical property of the SWNT/Nafion suspension is studied by means of reversible oxidative quenching behavior with different oxidants including H2 O2 and I2 . Additionally, a simple and rapid one-step method for encapsulating SWNT/Nafion suspension into silica for fluorescence studies is also described. The redox reactions of fluorescent SWNT/silica composite with H2 O2 and I2 , either in water or in air, are studied with respect to time. Under this condition, the fluorescence of SWNT/silica composite shows the exponential decay and the dependence on the thickness of the silica composite.
Download or read book Optical Properties of Covalently Anchored Single walled Carbon Nanotube Arrays on Silicon 100 Surfaces written by Jingxian Yu and published by . This book was released on 2006 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Carbon nanotubes and graphene for photonic applications written by E. Gaufrès and published by Elsevier Inc. Chapters. This book was released on 2013-08-31 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: This chapter describes how the semiconducting-single-wall nanotube (SWNT) extraction affects their luminescence properties and how such properties can be exploited to fabricate optical sources emitting in near-infrared wavelengths ranging from 1 to 2μm. The main applications of carbon nanotube (CNT) lasers are aimed at optical interconnects and biophotonics. We review recent achievements in obtaining optical gain in thin films doped with CNTs. Techniques for determining optical gain in CNTs are considered with particular focus on the variable strip length (VSL) method and choices to integrate nanotubes in the optical waveguide are discussed.
Download or read book Optical and Mechanical Properties of Single walled Carbon Nanotubes written by Matthew S. Marcus and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Springer Handbook of Nanomaterials written by Robert Vajtai and published by Springer Science & Business Media. This book was released on 2013-08-20 with total page 1234 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Springer Handbook of Nanomaterials covers the description of materials which have dimension on the "nanoscale". The description of the nanomaterials in this Handbook follows the thorough but concise explanation of the synergy of structure, properties, processing and applications of the given material. The Handbook mainly describes materials in their solid phase; exceptions might be e.g. small sized liquid aerosols or gas bubbles in liquids. The materials are organized by their dimensionality. Zero dimensional structures collect clusters, nanoparticles and quantum dots, one dimensional are nanowires and nanotubes, while two dimensional are represented by thin films and surfaces. The chapters in these larger topics are written on a specific materials and dimensionality combination, e.g. ceramic nanowires. Chapters are authored by well-established and well-known scientists of the particular field. They have measurable part of publications and an important role in establishing new knowledge of the particular field.
Download or read book Recent Advances in Density Functional Methods written by Delano Pun Chong and published by World Scientific. This book was released on 1995 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Of all the different areas in computational chemistry, density functional theory (DFT) enjoys the most rapid development. Even at the level of the local density approximation (LDA), which is computationally less demanding, DFT can usually provide better answers than Hartree-Fock formalism for large systems such as clusters and solids. For atoms and molecules, the results from DFT often rival those obtained by ab initio quantum chemistry, partly because larger basis sets can be used. Such encouraging results have in turn stimulated workers to further investigate the formal theory as well as the computational methodology of DFT.This Part II expands on the methodology and applications of DFT. Some of the chapters report on the latest developments (since the publication of Part I in 1995), while others extend the applications to wider range of molecules and their environments. Together, this and other recent review volumes on DFT show that DFT provides an efficient and accurate alternative to traditional quantum chemical methods. Such demonstration should hopefully stimulate frutiful developments in formal theory, better exchange-correlation functionals, and linear scaling methodology.
Download or read book Quantitative Optical Imaging of Single walled Carbon Nanotubes written by Lihong Huang Herman and published by . This book was released on 2013 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development and application of optical imaging tools and probing techniques have been the subject of exciting research. These tools and techniques allow for non-invasive, simple sample preparation and relatively fast measurement of electronic and optical properties. They also provided crucial information on optoelectronic device application and development. As the field of nanostructure research emerged, they were modified and employed to understand various properties of these structures at the diffraction limit of light. Carbon nanotubes, up to hundreds of micrometers long and several nanometers thin, are perfect for testing and demonstrating newly-developed optical measurement platforms for individual nanostructures, due to their heterogeneous nature. By employing two quantitative imaging techniques, wide-field on-chip Rayleigh scattering spectroscopy and spatial modulation confocal absorption microscopy, we investigate the optical properties of single-walled carbon nanotubes. These techniques allow us to obtain the Rayleigh scattering intensity, absolute absorption cross section, spatial resolution, and spectral information of single-walled carbon nanotubes. By probing the optical resonance of hundreds of single-walled carbon nanotubes in a single measurement, the first technique utilizes Rayleigh scattering mechanism to obtain the chirality of carbon nanotubes. The second technique, by using high numerical aperture oil immersion objective lenses, we measure the absolute absorption cross section of a singlewalled carbon nanotube. Combining all the quantitative values obtained from these techniques, we observe various interesting and recently discovered physical behaviors, such as long range optical coupling and universal optical conductivity on resonance, and demonstrate the possibility of accurate quantitative absorption measurement for individual structures at nanometer scale.
Download or read book Investigations Into the Optical Properties of Individual Air suspended Single walled Carbon Nanotubes written by Mark William Brennan Wilson and published by . This book was released on 2008 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Single-walled carbon nanotubes are naturally-forming nanostructures that have attracted considerable recent research interest due to their unique opto-electronic properties and comparative ease of fabrication. Two-thirds of nanotube species are semiconductors due to symmetry conditions imposed by their pseudo-one-dimensional tubular structure, and exhibit band-gap photoluminescence when isolated from their environment. Despite their elegant structural simplicity, fundamental properties of carbon nanotubes, such as their intrinsic quantum efficiency, non-linear excitonic recombination mechanisms, and the role of environmental effects, continue to be disputed in the literature. The design of an apparatus capable of observing nanotube photoluminescence is presented, along with conclusive proof of the observation of a single (9,8)-chirality nanotube in the form of spectral, spatial, and polarization-dependent measurements. The dependance of the excitation and emission spectra of a single nanotube on the excitation intensity is explored and the emission spectra found to be described by a Gaussian peak function, in contrast to previously-reported results. The unexpected ability to cause redshifts in the emission spectrum via the ambient humidity is discovered, which has consequences on experimental best practices. Photoluminescence quantum efficiencies are measured to be 4"2% and 13"6% for two different nanotubes. This is at the high end of the range for comparable literature results, and supports the validity of a recent literature value for the effective atomic absorption coefficient for carbon, AC=1.6 x 10^- 3nm^2, which is ten times greater than previous literature values. Pulsed power dependence studies show that the PL emission undergoes 'hard' saturation at an excitation intensity of 0.5 x 10^12photons/pulse/cm2, which is at least 100 times lower than previous reports and provides insight into non-linear decay dynamics. A novel theoretical model is developed to explain this saturation process, which yields an absorption co-efficient of AC=1.2"0.3 x 10^ - 3nm^2 as a fit parameter. Time-resolved photoluminescence dynamics are explored using femtosecond excitation correlation spectroscopy. Results suggest that the one-body decay processes are bi-exponential, with time constants of 31"4ps and 313"61ps, but also highlight the limitations of this technique in observing the expected very rapid (~1 ps) two-body Auger recombination process.
