Charge transfer and screening effects in polyynes encapsulated inside single-wall carbon nanotubes

2009 ◽  
Vol 80 (16) ◽  
Author(s):  
L. G. Moura ◽  
L. M. Malard ◽  
M. A. Carneiro ◽  
P. Venezuela ◽  
Rodrigo B. Capaz ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon

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.

Charge Transfer Dynamics in Single-Wall Carbon Nanotubes Mat: In Situ Raman Spectroscopy

2003 ◽  
Vol 785 ◽  
Author(s):  
S. Gupta ◽  
M. Hughes ◽  
A.H. Windle ◽  
J. Robertson
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Charge Transfer ◽  
Bond Length ◽  
Mechanical Response ◽  
Radial Breathing Mode ◽  
Single Wall Carbon Nanotubes ◽  
In Situ Raman Spectroscopy ◽  
Single Wall Carbon

ABSTRACTCarbon nanotubes-based actuator has been investigated using in situ Raman spectroscopy in order to understand the actuation mechanism and to determine associated parameters. We built an actuator from a sheet of single-wall carbon nanotubes (SWNT mat) and studied in several alkali metal (Li, Na, and K) and alkaline earth (Ca) halide solutions. 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, the variation of bonding was monitored with potential. In addition, the intensities of both the modes vary with either emptying/depleting or filling of the bonding and antibonding states due to electrochemical charge injection. We discuss the variation of intensity/frequency providing valuable information on the dynamics of charge transfer on the SWNT mat surface. We found the in-plane microscopic strain (∼ -0.25%) and the charge transfer per carbon atom (fc ∼ -0.005) as an upper bound for the electrolytes used. It is demonstrated that though the present analyses does comply with the proposition made earlier, but the quantitative estimates of the associated parameters are significantly lower if compared with those of reported values for carbon nanotubes. Moreover, the extent of variation (i.e. coupled electro-chemo-mechanical response) does depend upon the type of counter-ion used. The cyclic voltammetry (CV) is also described briefly.

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.

Manipulating single-wall carbon nanotubes by chemical doping and charge transfer with perylene dyes

2009 ◽  
Vol 1 (3) ◽  
pp. 243-249 ◽  
Author(s):  
Christian Ehli ◽  
Christian Oelsner ◽  
Dirk M. Guldi ◽  
Aurelio Mateo-Alonso ◽  
Maurizio Prato ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Single Wall Carbon Nanotubes ◽  
Chemical Doping ◽  
Single Wall Carbon

Optically enhanced charge transfer between C60and single-wall carbon nanotubes in hybrid electronic devices

Nanoscale ◽  
2014 ◽  
Vol 6 (1) ◽  
pp. 572-580 ◽  
Author(s):  
Christopher S. Allen ◽  
Guoquan Liu ◽  
Yabin Chen ◽  
Alex W. Robertson ◽  
Kuang He ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Electronic Devices ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon

CHARGE TRANSFER IN DOPED SINGLE WALL CARBON NANOTUBES

2003 ◽  
Vol 135-136 ◽  
pp. 717-719 ◽  
Author(s):  
T. Pichler ◽  
A. Kukovecz ◽  
H. Kuzmany ◽  
H. Kataura
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon

scholarly journals Reversible electron charge transfer in single-wall carbon nanotubes

2008 ◽  
Vol 10 (2) ◽  
pp. 1-4 ◽  
Author(s):  
Sara Costa ◽  
Alicja Bachmatiuk ◽  
Ewa Borowiak-Palen
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Electronic Properties ◽  
Acid Treatment ◽  
Diameter Distribution ◽  
Optical Absorption Spectroscopy ◽  
Single Wall Carbon Nanotubes ◽  
Electron Charge ◽  
Single Wall Carbon ◽  
Electron Charge Transfer

Reversible electron charge transfer in single-wall carbon nanotubes Single-wall carbon nanotubes (SWCNT) have proved to be very special materials due to their unique electronic properties. Over the last years many scientists have dedicated their research to the study of the these materials as an electronic system. Amphoteric doping effects (n-type and p-type), which can be reversed, became a very popular way of manipulating the optic and electronic properties of carbon nanotubes. In the particular case of SWCNT, the most common and widely used procedure, which changes their properties, is acid treatment applied as a purification procedure. The effect of the addition of this kind of the dopant has been widely studied but not fully understood so far. Here, we present a study, of two kinds of SWCNT, produced within different techniques: (i) chemical vapors deposition and (ii) laser ablation. The main difference between the two types is the diameter distribution of the obtained materials, which is broad in the first technique and narrow in the second. After the acid treatment it is possible to observe a diameter sensitive doping effect on both samples. Resonance Raman spectroscopy, optical absorption spectroscopy (OAS) in UV/Vis/NIR and the Fourier transform middle-infrared (FTIR) spectroscopy have been applied for the characterization of the samples.

Immobilizing NIR absorbing azulenocyanines onto single wall carbon nanotubes—from charge transfer to photovoltaics

2012 ◽  
Vol 3 (5) ◽  
pp. 1472 ◽  
Author(s):  
Mine Ince ◽  
Juergen Bartelmess ◽  
Daniel Kiessling ◽  
Konstantin Dirian ◽  
M. Victoria Martínez-Díaz ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon
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