A novel burning technique for making a semiconducting single-walled carbon nanotubes （SWNTs） transistor assembled by the dielectrophoretic force was suggested. The fabrication process consisted of two steps. First, ...A novel burning technique for making a semiconducting single-walled carbon nanotubes （SWNTs） transistor assembled by the dielectrophoretic force was suggested. The fabrication process consisted of two steps. First, to align and attach a bundle of SWNTs between the source and drain, the alternating （AC） voltage was applied to the electrodes. When a bundle of SWNTs was connected between two electrodes, some of metallic nanotubes and semi-conducing nanotubes existed together. The second step is to burn the metallic SWNTS by applying the voltage between two electrodes. With increasing the voltage, more current flowed through the metallic SWNTs, thus, the metallic SWNTs burnt earlier than the semiconducting one. This technique enables to obtain only semi-conducting SWNTs connection in the transistor. Through the 1--V characteristic graph, the moment of metallic SWNTs burning and the characteristic of semi-conducing nanotubes were verified.展开更多
For MHD flows in a rectangular duct with unsymmetrical walls, two analytical solutions have been obtained by solving the gov- erning equations in the liquid and in the walls coupled with the boundary conditions at flu...For MHD flows in a rectangular duct with unsymmetrical walls, two analytical solutions have been obtained by solving the gov- erning equations in the liquid and in the walls coupled with the boundary conditions at fluid-wall interface. One solution of ＇Case I＇ is for MHD flows in a duct with side walls insulated and unsymmetrical Hartmann walls of arbitrary conductivity, and another one of ＇Case II＇ is for the flows with unsymmetrical side walls of arbitrary conductivity and Hartmann walls perfectly conductive. The walls are unsymmetrical with either the conductivity or the thickness different from each other. The solutions, which include three parts, well reveal the wall effects on MHD. The first part represents the contribution from insulated walls, the second part represents the contribution from the conductivity of the walls and the third part represents the contribution from the unsymmetri- cal walls. The solution is reduced to the Hunt＇s analytical solutions when the walls are symmetrical and thin enough. With wall thickness runs from 0 to co, there exist many solutions for a fixed conductance ratio. The unsymmetrical walls have great effects on velocity distribution. Unsymmetrical jets may form with a stronger one near the low conductive wall, which may introduce stronger MHD instability. The pressure gradient distributions as a function of Hartmann number are given, in which the wall effects on the distributions are well illustrated.展开更多
Polymer light-emitting electrochemical cells (PLECs) employ a thin layer of a luminescent conjugated polymer admixed with an ionic source and an ionic conductor for the in-situ formation of p-i-n junction and subseque...Polymer light-emitting electrochemical cells (PLECs) employ a thin layer of a luminescent conjugated polymer admixed with an ionic source and an ionic conductor for the in-situ formation of p-i-n junction and subsequent efficient injections of both electrons and holes.The junction formation enables the use of air-stable conductors as the cathode and a relatively thick emissive polymer layer that is more compatible with low-cost solution-based processes.This paper overviews the operation mechanism of the PLECs,the properties and drawbacks of the devices.The employment of crosslinkable ionic conductors to stabilize the p-i-n junction is reviewed.The resulting static junction electroluminesces light at high brightness,high efficiency,and prolonged lifetime.Silver paste and carbon nanotubes can be used as the cathode,thus,PLECs were fabricated by lamination.Using single wall carbon nanotubes coated elastic substrate as both anode and cathode,the PLECs can be made highly stretchable.展开更多
The metal-conducting single-walled carbon nanotubes （m-SWNTs） with small diameters （0.7 nm-1.1 nm） are selectively removed from the single-walled carbon nanotubes （SWNTs） by using HNOJH2SO4 mixed solution. Semic...The metal-conducting single-walled carbon nanotubes （m-SWNTs） with small diameters （0.7 nm-1.1 nm） are selectively removed from the single-walled carbon nanotubes （SWNTs） by using HNOJH2SO4 mixed solution. Semiconducting single- walled carbon nanotubes （s-SWNTs） can be separated efficiently from the SWNTs with high controllability and purity based on this novel method, and the outcome is characterized by Raman spectrum. Moreover, the organic field effect transistors （OFETs） are fabricated based on the poly （3-hexylthiophene-2, 5-diyl） （P3HT）, and untreated SWNTs and separated SWNTs （s-SWNTs） are mixed with P3HT, respectively. It could be found that the P3HT/s-SWNT device exhibits a better field effect characteristic compared with the P3HT device. The current on/off ratio is increased by 4 times, the threshold voltage is also increased from -28 V to -22 V, and the mobility is increased from 3 ~ 10.3 cmZNs to 5 x 10.3 cm2/Vs.展开更多
基金Project (2010-0008-276) supported for two years by Pusan National University Research GrantNCRC(National Core Research Center) through the National Research Foundation of Korea funded by the Ministry of Education, Science and TechnologyPusan National University Research Grant, 2009
文摘A novel burning technique for making a semiconducting single-walled carbon nanotubes （SWNTs） transistor assembled by the dielectrophoretic force was suggested. The fabrication process consisted of two steps. First, to align and attach a bundle of SWNTs between the source and drain, the alternating （AC） voltage was applied to the electrodes. When a bundle of SWNTs was connected between two electrodes, some of metallic nanotubes and semi-conducing nanotubes existed together. The second step is to burn the metallic SWNTS by applying the voltage between two electrodes. With increasing the voltage, more current flowed through the metallic SWNTs, thus, the metallic SWNTs burnt earlier than the semiconducting one. This technique enables to obtain only semi-conducting SWNTs connection in the transistor. Through the 1--V characteristic graph, the moment of metallic SWNTs burning and the characteristic of semi-conducing nanotubes were verified.
基金supported by the National Natural Science Foundation of China(Grant Nos.11125212 and 50936066)the International Thermonuclear Experimental Reactor Project in China(Grant No.2013GB11400)
文摘For MHD flows in a rectangular duct with unsymmetrical walls, two analytical solutions have been obtained by solving the gov- erning equations in the liquid and in the walls coupled with the boundary conditions at fluid-wall interface. One solution of ＇Case I＇ is for MHD flows in a duct with side walls insulated and unsymmetrical Hartmann walls of arbitrary conductivity, and another one of ＇Case II＇ is for the flows with unsymmetrical side walls of arbitrary conductivity and Hartmann walls perfectly conductive. The walls are unsymmetrical with either the conductivity or the thickness different from each other. The solutions, which include three parts, well reveal the wall effects on MHD. The first part represents the contribution from insulated walls, the second part represents the contribution from the conductivity of the walls and the third part represents the contribution from the unsymmetri- cal walls. The solution is reduced to the Hunt＇s analytical solutions when the walls are symmetrical and thin enough. With wall thickness runs from 0 to co, there exist many solutions for a fixed conductance ratio. The unsymmetrical walls have great effects on velocity distribution. Unsymmetrical jets may form with a stronger one near the low conductive wall, which may introduce stronger MHD instability. The pressure gradient distributions as a function of Hartmann number are given, in which the wall effects on the distributions are well illustrated.
基金supported by the National Science Foundation (ECCS1028412)
文摘Polymer light-emitting electrochemical cells (PLECs) employ a thin layer of a luminescent conjugated polymer admixed with an ionic source and an ionic conductor for the in-situ formation of p-i-n junction and subsequent efficient injections of both electrons and holes.The junction formation enables the use of air-stable conductors as the cathode and a relatively thick emissive polymer layer that is more compatible with low-cost solution-based processes.This paper overviews the operation mechanism of the PLECs,the properties and drawbacks of the devices.The employment of crosslinkable ionic conductors to stabilize the p-i-n junction is reviewed.The resulting static junction electroluminesces light at high brightness,high efficiency,and prolonged lifetime.Silver paste and carbon nanotubes can be used as the cathode,thus,PLECs were fabricated by lamination.Using single wall carbon nanotubes coated elastic substrate as both anode and cathode,the PLECs can be made highly stretchable.
基金supported by the National Natural Science Foundation of China(Nos.60676051,60876046,60906022)the Natural Science Fund of Tianjin(Nos.07JCYBJC12700 and 10JCYBJC01100)
文摘The metal-conducting single-walled carbon nanotubes （m-SWNTs） with small diameters （0.7 nm-1.1 nm） are selectively removed from the single-walled carbon nanotubes （SWNTs） by using HNOJH2SO4 mixed solution. Semiconducting single- walled carbon nanotubes （s-SWNTs） can be separated efficiently from the SWNTs with high controllability and purity based on this novel method, and the outcome is characterized by Raman spectrum. Moreover, the organic field effect transistors （OFETs） are fabricated based on the poly （3-hexylthiophene-2, 5-diyl） （P3HT）, and untreated SWNTs and separated SWNTs （s-SWNTs） are mixed with P3HT, respectively. It could be found that the P3HT/s-SWNT device exhibits a better field effect characteristic compared with the P3HT device. The current on/off ratio is increased by 4 times, the threshold voltage is also increased from -28 V to -22 V, and the mobility is increased from 3 ~ 10.3 cmZNs to 5 x 10.3 cm2/Vs.
