Electronic Properties of Potassium-Doped Carbon Nanotube Lattice

1999 ◽  
Vol 593 ◽  
Author(s):  
Susumu Saito
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Charge Transfer ◽  
Carbon Nanotube ◽  
Density Of States ◽  
Fermi Energy ◽  
Level Density ◽  
Crystalline Lattice ◽  
Electronic Band ◽  
Tile Size

ABSTRACTWe study the electronic structure of potassium-doped crystalline lattice of so-called (10.10) carbon nanotubes in the framework of the density-finctional theory. Tie stoichiometrv of the material studied is K2C80 which was originally proposed in designing the superconducting doped nanotube material based on tile size of dopants and the charge transfer being favorable for superconductivity. Electronic band dispersions obtained are actually found to be very similar to those of the pristine (10,10) nanotube lattice with the upward shift of the Fermi energy by 1 eV above the second conduction-band miinimum. Tie system therefore possesses higher Fermi-level density of states than the pristine material with rather sinmple charge transfer from K to C sites, and is confirned to be a good candidate for a naxiotube superconductor.

Dependence of the Second-order G'-band Profile on the Electronic Structure of Single-wal Nanotubes

2001 ◽  
Vol 706 ◽  
Author(s):  
A. G. Souza Filho ◽  
A. Joribo ◽  
G. Dresselhaus ◽  
M. S. Dresselhaus ◽  
A. K. Swan ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Raman Spectra ◽  
Density Of States ◽  
Resonance Raman ◽  
Second Order ◽  
Electronic Density ◽  
Van Hove Singularities ◽  
Band Profile ◽  
Resonance Raman Spectra

AbstractWe analyze the dependence of the second-order G'-band profile in terms of their (n,m) indices by measuring the resonance Raman spectra of several semiconducting and metalic isolated single wal carbon nanotubes. We show that this profile is very sensitive to the electronic structure, thus making it possible to get structural (n,m) information and to probe the splitting of the van Hove singularities in the electronic density of states due to the trigona warping effect.

Electrochemical Tuning of Single-Wall Carbon Nanotube Mat and Investigations on Actuator Mechanism

2004 ◽  
Vol 855 ◽  
Author(s):  
S. Gupta ◽  
M. Hughes ◽  
J. Robertson
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Carbon Nanotube ◽  
Bond Length ◽  
Upper Bound ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon Nanotube ◽  
Single Wall Carbon ◽  
Electrochemical Tuning

ABSTRACTElectrochemical tuning of single-wall carbon nanotubes has been investigated using in situ Raman spectroscopy. We built a linear actuator from single-wall carbon nanotube mat and studied in several alkali metal (Li, Na, and K) and alkaline earth (Ca) halide solutions. The variation of bonding with electrochemical biasing was monitored using in situ Raman. This is since Raman can detect changes in C-C bond length: the radial breathing mode (RBM) at ∼190 cm−1 varies inversely with the nanotube diameter and the G band at ∼1590 cm−1 varies with the axial bond length. In addition, the intensities of both the modes vary significantly in a nonmonotonic manner pointing at the emptying/depleting or filling of the bonding and anti-bonding states - electrochemical charge injection. We discuss the variation of spectroscopic observables (intensity/frequency) of these modes providing valuable information on the charge transfer dynamics on the single-wall carbon nanotubes mat surface. We found the in-plane compressive strain (∼ -0.25%) and the charge transfer per carbon atom (fc ∼ -0.005) as an upper bound for the electrolytes used i.e. CaCl2. These results can be quantitatively understood in terms of the changes in the energy gaps between the one-dimensional van Hove singularities in the electron density of states arising possibly due to the alterations in the overlap integral of π bonds between the p orbitals of the adjacent carbon atoms. Moreover, the extent of variation of the absolute potential of the Fermi level or alternatively modification of band gap is estimated from modeling Raman intensity to be around 0.1 eV as an upper bound for CaCl2.

Photoconductivity Study of Modified Single-Wall Carbon Nanotube/ Oxotitanium Phthalocyanine

2007 ◽  
Vol 121-123 ◽  
pp. 631-636
Author(s):  
T. Li ◽  
X.B. Zhang ◽  
Y. Li ◽  
W.Z. Huang ◽  
X.Y. Tao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Carbon Nanotube ◽  
Chemical Modification ◽  
Single Wall Carbon Nanotubes ◽  
Charge Generation ◽  
Photoinduced Charge Transfer ◽  
Single Wall Carbon ◽  
Discharge Method ◽  
Photoinduced Charge

Single-wall Carbon nanotubes (SWNTs) bonded with dodecylamine groups were obtained by chemical modification. The modified SWNTs showed improved solubility in organic solvents. Both its chemical and aggregated structure was characterized by means of FTIR and TEM. The photoconductivity of oxotitanium phthalocyanine (TiOPc) doped with the modified SWNTs was investigated by xerographic photoinduced discharge method. The results showed that the photosensitivity of the double-layered photoreceptor composed of the SWNTs/TiOPc composite as charge generation material was higher than that of pristine TiOPc, and the sensitivity increased with the content of modified SWNTs in the composites. It is the photoinduced charge transfer between TiOPc and SWNTs that contributes to the improved photosensitivity of the modified SWNTs/TiOPc composites.

Effect of boron impurity in a carbon nanotube superlattice

2017 ◽  
Vol 31 (14) ◽  
pp. 1750106
Author(s):  
Zahra Karimi Ghobadi ◽  
Aliasghar Shokri ◽  
Sonia Zarei
Keyword(s):  
Carbon Nanotube ◽  
Band Structure ◽  
Boron Atom ◽  
Density Of States ◽  
Nearest Neighbor ◽  
Electronic Band Structure ◽  
Tight Binding ◽  
Topological Defects ◽  
Electronic Band ◽  
Neighbor Approximation

In this work, the influence of boron atom impurity is investigated on the electronic properties of a single-wall carbon nanotube superlattice which is connected by pentagon–heptagon topological defects along the circumference of the heterojunction of these superlattices. Our calculation is based on tight-binding [Formula: see text]-electron method in nearest-neighbor approximation. The density of states (DOS) and electronic band structure in presence of boron impurity has been calculated. Results show that when boron atom impurity and nanotube atomic layers have increased, electronic band structure and the DOS have significant changes around the Fermi level.

Interaction between Carbon Nanotube and Mg Surface: Ab-Initio Investigation

2007 ◽  
Vol 546-549 ◽  
pp. 481-484
Author(s):  
Jian Feng Wan ◽  
Yan Qiong Fei ◽  
Jian Nong Wang
Keyword(s):  
Charge Transfer ◽  
Carbon Nanotube ◽  
Ab Initio ◽  
Density Of States ◽  
Electronic Structures ◽  
Metal Surfaces ◽  
Bond Order ◽  
Chemical Bonds ◽  
Single Walled Carbon Nanotube ◽  
Work Functions

ab-initio calculations on the interaction between the single-walled carbon nanotube (SWCN) and the Mg (0001) surface have been reported. It was found that the charge transfer from metal surfaces to the nanotubes takes place depending on both the electronic structures of the nanotubes and the work functions of the metal surfaces. The stable geometries for the nanotube between two consecutive objectives with C-Mg chemical bonds formed. The interaction energy in the most stable geometry is found to be CNT’s structural dependence. Concerning the electronic properties, the most stable structure showed a decrease in the density of states near the Fermi level due to the formation of C-Mg bonds enhancing the metallic character of the nanotube by the contact with the surface. The nature of the nanotube-interface interaction for nanotubes of larger diameters has been also discussed based on the calculated bond order.

First-principle investigation of electronic structure and mechanical properties of AlMgB14

2009 ◽  
Vol 1224 ◽  
Author(s):  
Liwen F Wan ◽  
Scott P Beckman
Keyword(s):  
Mechanical Properties ◽  
Electronic Structure ◽  
Ab Initio ◽  
Density Of States ◽  
Fermi Energy ◽  
First Principle ◽  
Metal Atoms ◽  
Structural And Electronic Properties ◽  
The Impact ◽  
Atomic And Electronic Structure

AbstractThe structural and electronic properties of AlMgB14 are investigated using ab initio methods. The impact of vacancies and electron doping on the crystal’s atomic and electronic structure is investigated. It is found that removing metal atoms does not influence the density of states, except for changes to the Fermi energy. The density of states of the off-stoichiometric Al0.75Mg0.75B14 crystal and the AlMgB14 crystal with five electrons removed are nearly identical. The removal of six electrons results in an 11% contraction in the crystal’s volume. This is associate with the removal of electrons from the B atoms’ 2p-states.

Solution-Based Fabrication of Carbon Nanotube Gas Sensor by Using Dielectrophoresis and Spin-Column Chromatography

2013 ◽  
Vol 699 ◽  
pp. 915-920
Author(s):  
Hideaki Watanabe ◽  
Hiroki Komure ◽  
Michihiko Nakano ◽  
Junya Suehiro
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Carbon Nanotube ◽  
Gas Sensor ◽  
Column Chromatography ◽  
Gas Sensors ◽  
Single Walled Carbon Nanotubes ◽  
Sensor Response ◽  
Spin Column ◽  
Walled Carbon Nanotubes

Single-walled carbon nanotubes (SWCNTs) gas sensor has attracted a great deal of attention because of their remarkable properties. The sensor response is attribute to the semiconducting CNT whose electronic properties depend on its chirality. The authors have previously found that the sensor response increased by using separated semiconducting SWCNTs from a mixture with metallic one. Since the electronic structure (metallic or semiconducting) of CNTs is governed by their chirality, a chirality-selective fabrication of CNT gas sensor is essential to improve their performance. In this study, we proposed chirality-based separation of semiconducting SWCNTs by using spin-column chromatography. Pristine CNT suspension was separated into three fractions that had different chiralities of semiconducting SWCNTs. Separated semiconducting CNTs of each fraction were used for fabrication of three CNT gas sensors by dielectrophoresis. Comparison of these sensor responses to NO2 revealed that sensor response depended on the chirality.

Study of Adsorption Properties of O2, CO2, NO2 and SO2 on Si-Doped Carbon Nanotube Using Density Functional Theory

2011 ◽  
Vol 110-116 ◽  
pp. 315-320
Author(s):  
M. R. Sonawane ◽  
B. J. Nagare
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Carbon Nanotube ◽  
Binding Energy ◽  
Density Of States ◽  
Density Functional ◽  
Population Analysis ◽  
Energy Charge ◽  
Basis Set ◽  
Functional Theory

We report reactivity of silicon doped single walled carbon nanotube (Si-CNT) towards the small atmospheric gas molecules O2, CO2, SO2and NO2using density functional theory based on the numerical basis set method. The reactivity of these molecules is explained on the basis of electronic properties such as binding energy, charge density, charge transfer and density of states. The large change in binding energy and formation of sigma (σ) bonds between silicon and oxygen atoms shows the strong chemisorption of the molecules on Si-CNT. Further, the density of states analysis clearly illustrate the reduction in the band gap and creation of extra state near the Fermi level, which acts as a catalytic center for adsorption of the molecules. The Mulliken population analysis indicates the charge transfer from Si-CNT to the molecules due to their more electronegativity.

Different Aspects of Single Wall Carbon Nanotube Functionalization by Aniline Adsorption; Quantum Mechanics/Molecular Mechanics Study

2015 ◽  
Vol 32 ◽  
pp. 1-16
Author(s):  
Mohamood Abedini ◽  
Mohammad Izadyar ◽  
Ali Nakhaeipour
Keyword(s):  
Activation Energy ◽  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Carbon Nanotube ◽  
Molecular Mechanics ◽  
Molecular Orbital ◽  
Frontier Molecular Orbital ◽  
Chemical Hardness ◽  
Molecular Orbital Analysis ◽  
Walled Carbon Nanotubes

In this research, kinetics and mechanism of aniline adsorption on different single-walled carbon nanotubes (SWCNT) was investigated, using 2-layer ONIOM (Our own N-layered Integrated molecular Orbital and molecular Mechanics) method at the ONIOM (B3LYP/6-31G (d);UFF) level. Various orientations of aniline relative to the carbon nanotube surface were investigated. To investigate the adsorption of aniline, three models including open-ended (model 1), cap-ended (model 2) and 1-cap-ended (model 3) SWCNT have been modeled. Calculated activation energies of adsorption showed that model 2 has the lowest activation energy of 40.8 kcal.mol-1. Natural bond orbital and frontier molecular orbital analysis confirmed the charge transfer from the aniline to the SWCNT. Density of states analysis showed that Fermi level is shifted towards the positive values after aniline adsorption which confirmed the effective interactions between the aniline and the SWCNT. According to the quantum theory of atoms in molecules studies, new bonds formed between the SWCNT and aniline which possess a covalence nature. Finally, based on the quantum reactivity indices, new linear correlations between the chemical hardness, charge transfer and activation energy and the inverse relationship of the electrophilic property and chemical electronic potential in the functionalized carbon nanotubes were obtained. Wiberg bond index calculations show that this reaction is carried out through an asynchronous concerted mechanism. Asynchronicity value in the case of model 2 is higher than other models.

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