Anisotropic Strain-Field-Induced Change of the Electronic Conductivity of Graphene Sheets and Carbon Nanotubes

2012 ◽  
Author(s):  
Masato Ohnishi ◽  
Hiroshi Kawakami ◽  
Yusuke Suzuki ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional ◽  
Electronic Conductivity ◽  
Deformation Characteristic ◽  
Strain Sensor ◽  
Functional Theory ◽  
Highly Sensitive ◽  
Mems Technology ◽  
Stable Performance ◽  
The Relationship

Since the discovery of carbon nanotubes (CNTs), there have been many efforts to develop various electronic devices and sensors. The authors have also validated the possibility of a highly sensitive strain sensor using popular resin in which multi-walled CNTs (MWNTs) were dispersed uniformly. It is, however, indispensable for clarifying how to change the electronic state of a deformed CNT for assuring the stable performance of the sensor because the reported sensitivity has ranged widely. In this study, the relationship between the deformation characteristic of a CNT under strain and its electronic conductivity was analyzed quantitatively. The analysis result obtained from density functional theory (DFT) calculation showed that the orbital hybridization was occured when the local curvature exceeded about 0.3 Å−1, inducing the decrease in the band gap. Based on the analytical results, a two-dimensional strain sensor was developed by applying buckling deformation-induced conductivity change of MWNTs by using MEMS technology.

Effect of Anisotropic Strain Field on the Electronic Conductance of Carbon Nanotubes

2013 ◽  
Author(s):  
Masato Ohnishi ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional ◽  
Electronic Devices ◽  
Deformation Characteristic ◽  
Functional Theory ◽  
Highly Sensitive ◽  
Electronic Conductance ◽  
Stable Performance ◽  
The Relationship ◽  
Walled Cnts

Since carbon nanotubes (CNTs) have unique electronic and mechanical properties, there have been many efforts to develop CNTs-based electronic devices and sensors. The authors have also validated the possibility of a highly sensitive strain sensor using popular resin in which multi-walled CNTs (MWNTs) were dispersed uniformly. It is, however, indispensable for clarifying how to change the electronic state of a deformed CNT for assuring the stable performance of the sensor because the reported sensitivity has ranged widely. In this study, the relationship between the deformation characteristic of a CNT under strain and its electronic properties was analyzed. The analysis result obtained from density functional theory (DFT) calculation showed that the orbital hybridization was occurred when the maximum local dihedral angle exceeded 10–20° and 25–30° in GNRs and CNTs, respectively, which induced the band gap.

Highly Sensitive 2D Strain Sensor Using Carbon Nanotube

2013 ◽  
Author(s):  
Hiroshi Kawakami ◽  
Masato Ohnishi ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strain ◽  
Electronic Conductivity ◽  
Strain Sensor ◽  
Applied Strain ◽  
Uniaxial Strain ◽  
Sensitive Strain ◽  
Highly Sensitive ◽  
2D Strain ◽  
Walled Carbon Nanotubes

A new highly sensitive strain measurement method has been developed by applying the strain-induced change of the electronic conductivity of CNTs. It is reported that most multi-walled carbon nanotubes (MWCNTs) show metallic conductivity and they are rather cheap comparing with single-walled carbon nanotubes (SWCNTs). However, it was found that the electric conductivity of MWCNTs changes drastically under uniaxial strain because of the drastic change of their band gap. Therefore, the authors have developed a highly sensitive strain sensor which can detect the local strain distribution by using MWCNTs. In order to design a new sensor using MWCNT, it is very important to control the shape of the MWCNTs under strain. Thus, a method for controlling the shape of the MWCNTs was developed by applying a chemical vapor deposition (CVD) technique. It was found that the shape of the grown MWCNT could be controlled by changing the average thickness of the catalyst and the deposition temperature of the MWCNT. The electrical resistance of the grown MWCNT changed almost linearly with the applied strain, and the maximum strain sensitivity obtained under the application of uniaxial strain was about 10%/1000-μstrain (gauge factor: 100). A two-dimensional strain sensor, which consists of area-arrayed fine bundles of MWCNTs, has been developed by applying MEMS technology. Under the application of compressive strain, the electric resistance was confirmed to increase almost linearly with the applied strain.

Two-Dimensional Strain-Distribution Sensor Using Carbon Nanotube-Dispersed Resin

2011 ◽  
Author(s):  
Yusuke Suzuki ◽  
Yusuke Ohashi ◽  
Masato Ohnishi ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional ◽  
Axial Strain ◽  
Electronic Conductivity ◽  
Applied Strain ◽  
Sensitive Strain ◽  
Two Dimensional ◽  
Electric Resistance ◽  
Highly Sensitive ◽  
Walled Carbon Nanotubes

A new highly sensitive strain measurement method has been developed by applying the change of the electronic conductivity of CNTs. It is reported that most multi-walled carbon nanotubes (MWCNTs) show metallic conductivity and they are rather cheap comparing with single-walled carbon nanotubes (SWCNTs). The effect of the longitudinal axial strain on the band structures of electrons in CNTs was analyzed by applying the abinitio calculation based on the density functional theory. The change of the band structure of a MWCNT under uni-axial strain was analyzed. It was found that the electric conductivity of (MWCNTs) changes drastically because of the large change of their band gap. Therefore, the authors have focused on the possibility of the application of MWCNTs to a highly sensitive strain sensor. Multi-walled CNTs were dispersed in various kinds of resins such as epoxy, polycarbonate, and polyisoprene to form a thin film which can be easily attached to rounded surfaces. The length and diameter of the CNTs were about 5 μm and 50 nm, respectively. One of the base materials of resin employed was polycarbonate and the volumetric concentration of CNT dispersed was about 11.5%. The thickness of the film was about 500 μm. Uni-axial strain was applied to the CNT-dispersed resin by applying a 4 point bending method, and the change of the electric resistance was measured. The range of the applied strain was from −0.025% to 0.025%. The electric resistance changed almost linearly with the applied strain. The ratio of the resistance change under the tensile strain was about 400%/%strain and that under the compressive strain was about 150%/%strain. The CNTs were also dispersed in polyisoprene by about 5%. Uni-axial tesile strain was also applied to the CNT-dispersed rubber. The maximum strain was 240%. It was found that the resistance of the rubber increased monotonically with the increase of the amplitude of the applied strain. The increase rate also increased with the amplitude of the applied strain, and the maximum rate reached about 25%/%strain. Two-dimensional strain fields were evaluated by using finely area-arrayed CNT-dispersed resin made by MEMS technology with spatial resolution of 50 μm.

scholarly journals High-Efficiency Electrocatalyst Phthalocyanine in Li/SOCl2 Batteries: From Experimental to Theoretical Investigation

2021 ◽  
Author(s):  
Liangting Chen ◽  
Xinyu Yang ◽  
Xiaoqing Wang ◽  
Guangfa Hu ◽  
Ronglan Zhang ◽  
...  
Keyword(s):  
Density Functional ◽  
High Efficiency ◽  
Electronic Conductivity ◽  
Practical Application ◽  
Discharge Time ◽  
Functional Theory ◽  
Battery Capacity ◽  
Voltage Hysteresis ◽  
The Relationship ◽  
Good Agreement

Abstract Li/SOCl2 batteries, which are used in various fields due to theirs easy-carry and brilliant electrochemical properties, have attracted much research. However, the existence of the voltage hysteresis has limited further practical application of this tiny device. Herein, three series of nineteen kinds of metal phthalocyanine electrocatalysts with excellent electronic conductivity were synthesized to improve Li/SOCl2 battery performance. The structure of the catalysts was verified by infrared spectroscopy, ultraviolet-visible spectroscopy, thermogravimetric analysis, and elemental analysis,. and these materials were used to develop the discharge time, output voltage, and discharge capacity of the Li/SOCl2 battery. With the addition of the phthalocyanine, the discharge time of the Li/SOCl2 battery lengthens by approximately 20%, and the voltage can be increased by 0.02~0.20 V. In addition, the actual battery capacity can also be raised by 20~50 %. Density functional theory was used to calculate the relationship between the metal center and catalytic activity and the results are in good agreement with the experimental which implies the electron density of the center metal is the key point in the electrocatalyst reaction.

Density-Functional Theory Studies of Step-Kinked Carbon Nanotubes

2011 ◽  
Vol 115 (10) ◽  
pp. 4235-4239 ◽  
Author(s):  
Xiaojun Wu ◽  
Rulong Zhou ◽  
Jinlong Yang ◽  
Xiao Cheng Zeng
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory

Ca12O12 nanocluster as highly sensitive material for the detection of hazardous mustard gas: Density-functional theory

2021 ◽  
pp. 109174
Author(s):  
Rudi Kartika ◽  
Forat H. Alsultany ◽  
Abduladheem Turki Jalil ◽  
Mustafa Z. Mahmoud ◽  
Mohammed N. Fenjan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Mustard Gas ◽  
Sensitive Material ◽  
Functional Theory ◽  
Gas Density ◽  
Highly Sensitive
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