The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Alan M. Bond - One of the best experts on this subject based on the ideXlab platform.
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Underpotential and overpotential Electrocrystallization of semiconducting silver-tetracyanoquinodimethane onto gold substrates from an ionic liquid
CrystEngComm, 2011Co-Authors: Huan Wang, Alan M. Bond, Chuan ZhaoAbstract:Electrocrystallization of nanoneedles and nanorods of silver-tetracyanoquinodimethane (AgTCNQ) onto a gold substrate has been achieved from the ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), containing dissolved TCNQ and Ag+. In ionic liquid media, underpotential deposition (UPD) and overpotential deposition (OPD) of metallic Ag at a gold electrode occur at more positive potentials than that for reduction of TCNQ to TCNQ−. In contrast, the reduction of TCNQ and Ag+ occurs at almost the same potential in MeCN. The different thermodynamics that apply in the ionic liquid environment enables controlled Electrocrystallization of AgTCNQvia potential-dependent mechanisms. Nanoneedles AgTCNQ could be obtained at 0.3 V vs.Fc0/+ (Fc = ferrocene), while nanorods could be formed at −0.2 V vs.Fc0/+. Raman, IR and X-ray diffraction data imply that the formation of highly pure and crystalline phase of AgTCNQ on gold, and that AgTCNQ electrocrystallized under UPD or OPD conditions only differ in morphology and not in phase. The study highlights the capability of the Electrocrystallization method to precisely control the morphology of nanomaterials, and also using ionic liquids as media for preparation of technologically important metal-TCNQ charge transfer complexes.
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Modified thermodynamics in ionic liquids for controlled Electrocrystallization of nanocubes, nanowires, and crystalline thin films of silver-tetracyanoquinodimethane.
Journal of the American Chemical Society, 2009Co-Authors: Chuan Zhao, Douglas R. Macfarlane, Alan M. BondAbstract:Electrocrystallization of nanocubes, nanorods, nanowires, and crystalline thin films of silver-tetracyanoquinodimethane (AgTCNQ) onto glassy carbon, indium tin oxide, and platinum electrodes can be achieved from ionic liquids containing dissolved TCNQ and Ag(I) salts. In conventional molecular organic solvents, such as acetonitrile, the reduction of TCNQ and Ag(+) occurs at almost the same potential. In contrast, the different thermodynamics that apply to the room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF(4)), give rise to a large potential separation in the two processes, which enables Electrocrystallization of AgTCNQ to be undertaken via two distinctly different, potential-dependent mechanisms. Cyclic and microelectrode voltammetric, chronoamperometric, together with microscopic and spectroscopic techniques reveal that AgTCNQ nanostuctures of controlled morphology, size, density, and uniformity can be achieved by tuning the Electrocrystallization parameters such as potential, stoichiometric ratio of Ag(+) and TCNQ, and their concentrations, time, and ionic liquid viscosity by altering the water content. In the potential range of -0.1 to 0.3 V vs Fc(0/+) (Fc = ferrocene), Electrocrystallization occurs when Ag is deposited at electrode defect sites via a progressive nucleation and 3-D growth mechanism followed by reaction with TCNQ to produce structures ranging from nanocubes to nanowires. At higher stoichiometric concentrations of Ag(+) and more negative potentials (
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modified thermodynamics in ionic liquids for controlled Electrocrystallization of nanocubes nanowires and crystalline thin films of silver tetracyanoquinodimethane
Journal of the American Chemical Society, 2009Co-Authors: Chuan Zhao, Douglas R. Macfarlane, Alan M. BondAbstract:Electrocrystallization of nanocubes, nanorods, nanowires, and crystalline thin films of silver-tetracyanoquinodimethane (AgTCNQ) onto glassy carbon, indium tin oxide, and platinum electrodes can be achieved from ionic liquids containing dissolved TCNQ and Ag(I) salts. In conventional molecular organic solvents, such as acetonitrile, the reduction of TCNQ and Ag(+) occurs at almost the same potential. In contrast, the different thermodynamics that apply to the room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF(4)), give rise to a large potential separation in the two processes, which enables Electrocrystallization of AgTCNQ to be undertaken via two distinctly different, potential-dependent mechanisms. Cyclic and microelectrode voltammetric, chronoamperometric, together with microscopic and spectroscopic techniques reveal that AgTCNQ nanostuctures of controlled morphology, size, density, and uniformity can be achieved by tuning the Electrocrystallization parameters such as potential, stoichiometric ratio of Ag(+) and TCNQ, and their concentrations, time, and ionic liquid viscosity by altering the water content. In the potential range of -0.1 to 0.3 V vs Fc(0/+) (Fc = ferrocene), Electrocrystallization occurs when Ag is deposited at electrode defect sites via a progressive nucleation and 3-D growth mechanism followed by reaction with TCNQ to produce structures ranging from nanocubes to nanowires. At higher stoichiometric concentrations of Ag(+) and more negative potentials (<-0.1 V vs Fc(0/+)), extremely thin crystalline films could be obtained via overpotential deposition. Infrared and Raman spectroscopy, elemental analysis, together with X-ray diffraction and scanning electron microscopy all confirm the formation of highly pure AgTCNQ nanomaterials, which exhibit differences in morphology but not phase. The study highlights the capability of the Electrocrystallization method to precisely control the morphology of nanomaterials, and also the unprecedented opportunities provided by using ionic liquids as the medium for preparation of technologically important metal-TCNQ charge transfer complexes.
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Tuning the Electrocrystallization parameters of semiconducting Co[TCNQ]2-based materials to yield either single nanowires or crystalline thin films.
Journal of the American Chemical Society, 2007Co-Authors: Ayman Nafady, Alan M. Bond, Alexander Bilyk, Alexander R. Harris, Anand I. Bhatt, Anthony P. O'mullane, Roland De MarcoAbstract:Electrocrystallization of single nanowires and/or crystalline thin films of the semiconducting and magnetic Co[TCNQ]2(H2O)2 (TCNQ = tetracyanoquinodimethane) charge-transfer complex onto glassy carbon, indium tin oxide, or metallic electrodes occurs when TCNQ is reduced in acetonitrile (0.1 M [NBu4][ClO4]) in the presence of hydrated cobalt(II) salts. The morphology of the deposited solid is potential dependent. Other factors influencing the Electrocrystallization process include deposition time, concentration, and identity of the Co2+(MeCN) counteranion. Mechanistic details have been elucidated by use of cyclic voltammetry, chronoamperometry, electrochemical quartz crystal microbalance, and galvanostatic methods together with spectroscopic and microscopic techniques. The results provide direct evidence that Electrocrystallization takes place through two distinctly different, potential-dependent mechanisms, with progressive nucleation and 3-D growth being controlled by the generation of [TCNQ]•- at the el...
Chuan Zhao - One of the best experts on this subject based on the ideXlab platform.
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Underpotential and overpotential Electrocrystallization of semiconducting silver-tetracyanoquinodimethane onto gold substrates from an ionic liquid
CrystEngComm, 2011Co-Authors: Huan Wang, Alan M. Bond, Chuan ZhaoAbstract:Electrocrystallization of nanoneedles and nanorods of silver-tetracyanoquinodimethane (AgTCNQ) onto a gold substrate has been achieved from the ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), containing dissolved TCNQ and Ag+. In ionic liquid media, underpotential deposition (UPD) and overpotential deposition (OPD) of metallic Ag at a gold electrode occur at more positive potentials than that for reduction of TCNQ to TCNQ−. In contrast, the reduction of TCNQ and Ag+ occurs at almost the same potential in MeCN. The different thermodynamics that apply in the ionic liquid environment enables controlled Electrocrystallization of AgTCNQvia potential-dependent mechanisms. Nanoneedles AgTCNQ could be obtained at 0.3 V vs.Fc0/+ (Fc = ferrocene), while nanorods could be formed at −0.2 V vs.Fc0/+. Raman, IR and X-ray diffraction data imply that the formation of highly pure and crystalline phase of AgTCNQ on gold, and that AgTCNQ electrocrystallized under UPD or OPD conditions only differ in morphology and not in phase. The study highlights the capability of the Electrocrystallization method to precisely control the morphology of nanomaterials, and also using ionic liquids as media for preparation of technologically important metal-TCNQ charge transfer complexes.
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Modified thermodynamics in ionic liquids for controlled Electrocrystallization of nanocubes, nanowires, and crystalline thin films of silver-tetracyanoquinodimethane.
Journal of the American Chemical Society, 2009Co-Authors: Chuan Zhao, Douglas R. Macfarlane, Alan M. BondAbstract:Electrocrystallization of nanocubes, nanorods, nanowires, and crystalline thin films of silver-tetracyanoquinodimethane (AgTCNQ) onto glassy carbon, indium tin oxide, and platinum electrodes can be achieved from ionic liquids containing dissolved TCNQ and Ag(I) salts. In conventional molecular organic solvents, such as acetonitrile, the reduction of TCNQ and Ag(+) occurs at almost the same potential. In contrast, the different thermodynamics that apply to the room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF(4)), give rise to a large potential separation in the two processes, which enables Electrocrystallization of AgTCNQ to be undertaken via two distinctly different, potential-dependent mechanisms. Cyclic and microelectrode voltammetric, chronoamperometric, together with microscopic and spectroscopic techniques reveal that AgTCNQ nanostuctures of controlled morphology, size, density, and uniformity can be achieved by tuning the Electrocrystallization parameters such as potential, stoichiometric ratio of Ag(+) and TCNQ, and their concentrations, time, and ionic liquid viscosity by altering the water content. In the potential range of -0.1 to 0.3 V vs Fc(0/+) (Fc = ferrocene), Electrocrystallization occurs when Ag is deposited at electrode defect sites via a progressive nucleation and 3-D growth mechanism followed by reaction with TCNQ to produce structures ranging from nanocubes to nanowires. At higher stoichiometric concentrations of Ag(+) and more negative potentials (
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modified thermodynamics in ionic liquids for controlled Electrocrystallization of nanocubes nanowires and crystalline thin films of silver tetracyanoquinodimethane
Journal of the American Chemical Society, 2009Co-Authors: Chuan Zhao, Douglas R. Macfarlane, Alan M. BondAbstract:Electrocrystallization of nanocubes, nanorods, nanowires, and crystalline thin films of silver-tetracyanoquinodimethane (AgTCNQ) onto glassy carbon, indium tin oxide, and platinum electrodes can be achieved from ionic liquids containing dissolved TCNQ and Ag(I) salts. In conventional molecular organic solvents, such as acetonitrile, the reduction of TCNQ and Ag(+) occurs at almost the same potential. In contrast, the different thermodynamics that apply to the room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF(4)), give rise to a large potential separation in the two processes, which enables Electrocrystallization of AgTCNQ to be undertaken via two distinctly different, potential-dependent mechanisms. Cyclic and microelectrode voltammetric, chronoamperometric, together with microscopic and spectroscopic techniques reveal that AgTCNQ nanostuctures of controlled morphology, size, density, and uniformity can be achieved by tuning the Electrocrystallization parameters such as potential, stoichiometric ratio of Ag(+) and TCNQ, and their concentrations, time, and ionic liquid viscosity by altering the water content. In the potential range of -0.1 to 0.3 V vs Fc(0/+) (Fc = ferrocene), Electrocrystallization occurs when Ag is deposited at electrode defect sites via a progressive nucleation and 3-D growth mechanism followed by reaction with TCNQ to produce structures ranging from nanocubes to nanowires. At higher stoichiometric concentrations of Ag(+) and more negative potentials (<-0.1 V vs Fc(0/+)), extremely thin crystalline films could be obtained via overpotential deposition. Infrared and Raman spectroscopy, elemental analysis, together with X-ray diffraction and scanning electron microscopy all confirm the formation of highly pure AgTCNQ nanomaterials, which exhibit differences in morphology but not phase. The study highlights the capability of the Electrocrystallization method to precisely control the morphology of nanomaterials, and also the unprecedented opportunities provided by using ionic liquids as the medium for preparation of technologically important metal-TCNQ charge transfer complexes.
T.m. Yue - One of the best experts on this subject based on the ideXlab platform.
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Modeling of Electrocrystallization for pulse current electroforming of nickel
Applied Surface Science, 2001Co-Authors: K.p. Wong, K.c. Chan, T.m. YueAbstract:Abstract A mathematical model has been established for formulating the effect of different types of waveform on the three-dimensional Electrocrystallization of nickel electroforms. The model describes how the different types of waveform influence the rate of three-dimensional nucleation, J , the rate of three-dimensional step growth via surface diffusion path, J SD , and the rate of three-dimensional step growth via direct transfer path, J DT , at the cathodic surface. Moreover, the dynamic Electrocrystallization process including J , J SD and J DT was simulated. The highest maximum nucleation rate was obtained when a ramp-down waveform was employed. The highest step growth rate either via surface diffusion path or direct transfer path was obtained when conventional rectangular waveform was used. The best quality of electroforms, in terms of fine-grained structure, was found when a ramp-down waveform was employed. These results are in agreement with the findings of our previous studies.
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Modeling of Electrocrystallization for pulse current electroforming of nickel
Applied Surface Science, 2001Co-Authors: K.p. Wong, K.c. Chan, T.m. YueAbstract:A mathematical model has been established for formulating the effect of different types of waveform on the three-dimensional Electrocrystallization of nickel electroforms. The model describes how the different types of waveform influence the rate of three-dimensional nucleation, J, the rate of three-dimensional step growth via surface diffusion path, JSD, and the rate of three-dimensional step growth via direct transfer path, JDT, at the cathodic surface. Moreover, the dynamic Electrocrystallization process including J, JSD and JDT was simulated. The highest maximum nucleation rate was obtained when a ramp-down waveform was employed. The highest step growth rate either via surface diffusion path or direct transfer path was obtained when conventional rectangular waveform was used. The best quality of electroforms, in terms of fine-grained structure, was found when a ramp-down waveform was employed. These results are in agreement with the findings of our previous studies.Department of Industrial and Systems Engineerin
Mogens Brondsted Nielsen - One of the best experts on this subject based on the ideXlab platform.
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diindenothienoacene tetrathiafulvalene redox systems
RSC Advances, 2015Co-Authors: Mikkel A Christensen, Gabriel E Rudebusch, Christian R Parker, Cecilie Lindholm Andersen, Anders Kadziola, Michael M Haley, Ole Hammerich, Mogens Brondsted NielsenAbstract:Extended tetrathiafulvalenes with central diindenothienoacene cores were prepared and studied for their redox and spectroelectrochemical properties, which depended strongly on the orientation of the thiophene rings. The cations undergo remarkably strong associations, rendering them attractive as redox-controllable tectons in supramolecular chemistry, and in one case crystals were grown by Electrocrystallization.
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Diindenothienoacene–tetrathiafulvalene redox systems
RSC Advances, 2015Co-Authors: Mikkel A Christensen, Gabriel E Rudebusch, Christian R Parker, Cecilie Lindholm Andersen, Anders Kadziola, Michael M Haley, Ole Hammerich, Mogens Brondsted NielsenAbstract:Extended tetrathiafulvalenes with central diindenothienoacene cores were prepared and studied for their redox and spectroelectrochemical properties, which depended strongly on the orientation of the thiophene rings. The cations undergo remarkably strong associations, rendering them attractive as redox-controllable tectons in supramolecular chemistry, and in one case crystals were grown by Electrocrystallization.
K.p. Wong - One of the best experts on this subject based on the ideXlab platform.
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Modeling of Electrocrystallization for pulse current electroforming of nickel
Applied Surface Science, 2001Co-Authors: K.p. Wong, K.c. Chan, T.m. YueAbstract:Abstract A mathematical model has been established for formulating the effect of different types of waveform on the three-dimensional Electrocrystallization of nickel electroforms. The model describes how the different types of waveform influence the rate of three-dimensional nucleation, J , the rate of three-dimensional step growth via surface diffusion path, J SD , and the rate of three-dimensional step growth via direct transfer path, J DT , at the cathodic surface. Moreover, the dynamic Electrocrystallization process including J , J SD and J DT was simulated. The highest maximum nucleation rate was obtained when a ramp-down waveform was employed. The highest step growth rate either via surface diffusion path or direct transfer path was obtained when conventional rectangular waveform was used. The best quality of electroforms, in terms of fine-grained structure, was found when a ramp-down waveform was employed. These results are in agreement with the findings of our previous studies.
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Modeling of Electrocrystallization for pulse current electroforming of nickel
Applied Surface Science, 2001Co-Authors: K.p. Wong, K.c. Chan, T.m. YueAbstract:A mathematical model has been established for formulating the effect of different types of waveform on the three-dimensional Electrocrystallization of nickel electroforms. The model describes how the different types of waveform influence the rate of three-dimensional nucleation, J, the rate of three-dimensional step growth via surface diffusion path, JSD, and the rate of three-dimensional step growth via direct transfer path, JDT, at the cathodic surface. Moreover, the dynamic Electrocrystallization process including J, JSD and JDT was simulated. The highest maximum nucleation rate was obtained when a ramp-down waveform was employed. The highest step growth rate either via surface diffusion path or direct transfer path was obtained when conventional rectangular waveform was used. The best quality of electroforms, in terms of fine-grained structure, was found when a ramp-down waveform was employed. These results are in agreement with the findings of our previous studies.Department of Industrial and Systems Engineerin