The Experts below are selected from a list of 75 Experts worldwide ranked by ideXlab platform

V. Petrov - One of the best experts on this subject based on the ideXlab platform.

  • New real-time analytical applications of electrochemical quartz crystal microbalance Stoichiometry and phase composition monitoring of electrodeposited thin chalcogenide films.
    Analytica chimica acta, 2006
    Co-Authors: Milka T. Neshkova, V.d. Nikolova, V. Petrov
    Abstract:

    Abstract The electrochemical quartz crystal microbalance (EQCM) has recently gained increasing popularity as a powerful tool for electrochemical interface examinations. This paper reports on its great potential for developing new real-time analytical protocols. Potentiostatic Coulometry is used in conjunction with quartz crystal microgravimetry (QCMg) with controlled hydrodynamics to develop two new analytical procedures: real-time stoichiometry monitoring of electrodeposited binary chalcogenide films and phase composition quantification of electrodeposited ternary chalcogenide compounds. The newly developed EQCM methods are illustrated on the examples of Ag2+δSe-electrodeposited films and the electroformation of ternary CuAgSe-films. Both compounds have been successfully used as ion-selective membranes for flow-injection detectors. The experimental set-up including hydrodynamic control, the main strategy of the approach used and its scope and limitations are broadly discussed. The obtained data allow for real time profile monitoring of either stoichiometry (Ag2+δSe-case) or phase composition (CuAgSe-case).

  • Real-time stoichiometry monitoring of electrodeposited chalcogenide films via Coulometry and electrochemical quartz-crystal microgravimetry with hydrodynamic control. Ag2+δSe case
    Journal of Electroanalytical Chemistry, 2000
    Co-Authors: Milka T. Neshkova, V.d. Nikolova, V. Petrov
    Abstract:

    Potentiostatic Coulometry is used in conjunction with electrochemical quartz-crystal microgravimetry (EQCM) with controlled hydrodynamics to develop a new electroanalytical protocol for in situ composition monitoring of metal chalcogenide thin films. The approach, its application scope and limitations, are illustrated using the example of electrosynthesized AgySe thin films, successfully used previously for developing ion-selective sensors for Ag(I), cyanide and Hg(II). Well-defined flowing electrolyte conditions are achieved by the EQCM/submerged wall jet (SWJ) cell arrangement. The electrolyte flow rate through the nozzle is maintained constant between 5.5 and 250 cm3 min−1. The hydrodynamic control makes it possible to extend the range of the combined EQCM/coulometric approach to greater layer thickness consistent with that of membranes practically used in sensor preparation. The stoichiometric coefficient (y) profile of AgySe is monitored in situ for comparatively thick electrodeposited films (up to 800 nm). Two distinct features are clearly distinguished in the electrochemical formation of non-stoichiometric layers: in the zone adjacent to the substrate (i.e. between 170 and 270 nm) and for greater thickness (up to 800 nm). A mean value for y=2.24±0.06 is determined for the deposited layers, which is in good agreement with the values previously obtained by ex situ energy dispersive X-ray fluorescent microanalysis (EDAX).

Milka T. Neshkova - One of the best experts on this subject based on the ideXlab platform.

  • New real-time analytical applications of electrochemical quartz crystal microbalance Stoichiometry and phase composition monitoring of electrodeposited thin chalcogenide films.
    Analytica chimica acta, 2006
    Co-Authors: Milka T. Neshkova, V.d. Nikolova, V. Petrov
    Abstract:

    Abstract The electrochemical quartz crystal microbalance (EQCM) has recently gained increasing popularity as a powerful tool for electrochemical interface examinations. This paper reports on its great potential for developing new real-time analytical protocols. Potentiostatic Coulometry is used in conjunction with quartz crystal microgravimetry (QCMg) with controlled hydrodynamics to develop two new analytical procedures: real-time stoichiometry monitoring of electrodeposited binary chalcogenide films and phase composition quantification of electrodeposited ternary chalcogenide compounds. The newly developed EQCM methods are illustrated on the examples of Ag2+δSe-electrodeposited films and the electroformation of ternary CuAgSe-films. Both compounds have been successfully used as ion-selective membranes for flow-injection detectors. The experimental set-up including hydrodynamic control, the main strategy of the approach used and its scope and limitations are broadly discussed. The obtained data allow for real time profile monitoring of either stoichiometry (Ag2+δSe-case) or phase composition (CuAgSe-case).

  • Real-time stoichiometry monitoring of electrodeposited chalcogenide films via Coulometry and electrochemical quartz-crystal microgravimetry with hydrodynamic control. Ag2+δSe case
    Journal of Electroanalytical Chemistry, 2000
    Co-Authors: Milka T. Neshkova, V.d. Nikolova, V. Petrov
    Abstract:

    Potentiostatic Coulometry is used in conjunction with electrochemical quartz-crystal microgravimetry (EQCM) with controlled hydrodynamics to develop a new electroanalytical protocol for in situ composition monitoring of metal chalcogenide thin films. The approach, its application scope and limitations, are illustrated using the example of electrosynthesized AgySe thin films, successfully used previously for developing ion-selective sensors for Ag(I), cyanide and Hg(II). Well-defined flowing electrolyte conditions are achieved by the EQCM/submerged wall jet (SWJ) cell arrangement. The electrolyte flow rate through the nozzle is maintained constant between 5.5 and 250 cm3 min−1. The hydrodynamic control makes it possible to extend the range of the combined EQCM/coulometric approach to greater layer thickness consistent with that of membranes practically used in sensor preparation. The stoichiometric coefficient (y) profile of AgySe is monitored in situ for comparatively thick electrodeposited films (up to 800 nm). Two distinct features are clearly distinguished in the electrochemical formation of non-stoichiometric layers: in the zone adjacent to the substrate (i.e. between 170 and 270 nm) and for greater thickness (up to 800 nm). A mean value for y=2.24±0.06 is determined for the deposited layers, which is in good agreement with the values previously obtained by ex situ energy dispersive X-ray fluorescent microanalysis (EDAX).

Benjamin J. Wiley - One of the best experts on this subject based on the ideXlab platform.

  • Real-Time Visualization of Diffusion-Controlled Nanowire Growth in Solution
    Nano letters, 2014
    Co-Authors: Zuofeng Chen, Benjamin J. Wiley
    Abstract:

    This Letter shows that copper nanowires grow through the diffusion-controlled reduction of dihydroxycopper(I), Cu(OH)2–. A combination of Potentiostatic Coulometry, UV–visible spectroscopy, and thermodynamic calculations was used to determine the species adding to growing Cu nanowires is Cu(OH)2–. Cyclic voltammetry was then used to measure the diffusion coefficient of Cu(OH)2– in the reaction solution. Given the diameter of a Cu nanowire and the diffusion coefficient of Cu(OH)2–, we calculated the dependence of the diffusion-limited growth rate on the concentration of copper ions to be 26 nm s–1 mM–1. Independent measurements of the nanowire growth rate with dark-field optical microscopy yielded 24 nm s–1 mM–1 for the growth rate dependence on the concentration of copper. Dependence of the nanowire growth rate on temperature yielded a low activation energy of 11.5 kJ mol–1, consistent with diffusion-limited growth.

  • Real-Time Visualization of Diffusion-Controlled Nanowire Growth in Solution
    2014
    Co-Authors: Zuofeng Chen, Benjamin J. Wiley
    Abstract:

    This Letter shows that copper nanowires grow through the diffusion-controlled reduction of dihydroxycopper­(I), Cu­(OH)2–. A combination of Potentiostatic Coulometry, UV–visible spectroscopy, and thermodynamic calculations was used to determine the species adding to growing Cu nanowires is Cu­(OH)2–. Cyclic voltammetry was then used to measure the diffusion coefficient of Cu­(OH)2– in the reaction solution. Given the diameter of a Cu nanowire and the diffusion coefficient of Cu­(OH)2–, we calculated the dependence of the diffusion-limited growth rate on the concentration of copper ions to be 26 nm s–1 mM–1. Independent measurements of the nanowire growth rate with dark-field optical microscopy yielded 24 nm s–1 mM–1 for the growth rate dependence on the concentration of copper. Dependence of the nanowire growth rate on temperature yielded a low activation energy of 11.5 kJ mol–1, consistent with diffusion-limited growth

V.d. Nikolova - One of the best experts on this subject based on the ideXlab platform.

  • New real-time analytical applications of electrochemical quartz crystal microbalance Stoichiometry and phase composition monitoring of electrodeposited thin chalcogenide films.
    Analytica chimica acta, 2006
    Co-Authors: Milka T. Neshkova, V.d. Nikolova, V. Petrov
    Abstract:

    Abstract The electrochemical quartz crystal microbalance (EQCM) has recently gained increasing popularity as a powerful tool for electrochemical interface examinations. This paper reports on its great potential for developing new real-time analytical protocols. Potentiostatic Coulometry is used in conjunction with quartz crystal microgravimetry (QCMg) with controlled hydrodynamics to develop two new analytical procedures: real-time stoichiometry monitoring of electrodeposited binary chalcogenide films and phase composition quantification of electrodeposited ternary chalcogenide compounds. The newly developed EQCM methods are illustrated on the examples of Ag2+δSe-electrodeposited films and the electroformation of ternary CuAgSe-films. Both compounds have been successfully used as ion-selective membranes for flow-injection detectors. The experimental set-up including hydrodynamic control, the main strategy of the approach used and its scope and limitations are broadly discussed. The obtained data allow for real time profile monitoring of either stoichiometry (Ag2+δSe-case) or phase composition (CuAgSe-case).

  • Real-time stoichiometry monitoring of electrodeposited chalcogenide films via Coulometry and electrochemical quartz-crystal microgravimetry with hydrodynamic control. Ag2+δSe case
    Journal of Electroanalytical Chemistry, 2000
    Co-Authors: Milka T. Neshkova, V.d. Nikolova, V. Petrov
    Abstract:

    Potentiostatic Coulometry is used in conjunction with electrochemical quartz-crystal microgravimetry (EQCM) with controlled hydrodynamics to develop a new electroanalytical protocol for in situ composition monitoring of metal chalcogenide thin films. The approach, its application scope and limitations, are illustrated using the example of electrosynthesized AgySe thin films, successfully used previously for developing ion-selective sensors for Ag(I), cyanide and Hg(II). Well-defined flowing electrolyte conditions are achieved by the EQCM/submerged wall jet (SWJ) cell arrangement. The electrolyte flow rate through the nozzle is maintained constant between 5.5 and 250 cm3 min−1. The hydrodynamic control makes it possible to extend the range of the combined EQCM/coulometric approach to greater layer thickness consistent with that of membranes practically used in sensor preparation. The stoichiometric coefficient (y) profile of AgySe is monitored in situ for comparatively thick electrodeposited films (up to 800 nm). Two distinct features are clearly distinguished in the electrochemical formation of non-stoichiometric layers: in the zone adjacent to the substrate (i.e. between 170 and 270 nm) and for greater thickness (up to 800 nm). A mean value for y=2.24±0.06 is determined for the deposited layers, which is in good agreement with the values previously obtained by ex situ energy dispersive X-ray fluorescent microanalysis (EDAX).

Zuofeng Chen - One of the best experts on this subject based on the ideXlab platform.

  • Real-Time Visualization of Diffusion-Controlled Nanowire Growth in Solution
    Nano letters, 2014
    Co-Authors: Zuofeng Chen, Benjamin J. Wiley
    Abstract:

    This Letter shows that copper nanowires grow through the diffusion-controlled reduction of dihydroxycopper(I), Cu(OH)2–. A combination of Potentiostatic Coulometry, UV–visible spectroscopy, and thermodynamic calculations was used to determine the species adding to growing Cu nanowires is Cu(OH)2–. Cyclic voltammetry was then used to measure the diffusion coefficient of Cu(OH)2– in the reaction solution. Given the diameter of a Cu nanowire and the diffusion coefficient of Cu(OH)2–, we calculated the dependence of the diffusion-limited growth rate on the concentration of copper ions to be 26 nm s–1 mM–1. Independent measurements of the nanowire growth rate with dark-field optical microscopy yielded 24 nm s–1 mM–1 for the growth rate dependence on the concentration of copper. Dependence of the nanowire growth rate on temperature yielded a low activation energy of 11.5 kJ mol–1, consistent with diffusion-limited growth.

  • Real-Time Visualization of Diffusion-Controlled Nanowire Growth in Solution
    2014
    Co-Authors: Zuofeng Chen, Benjamin J. Wiley
    Abstract:

    This Letter shows that copper nanowires grow through the diffusion-controlled reduction of dihydroxycopper­(I), Cu­(OH)2–. A combination of Potentiostatic Coulometry, UV–visible spectroscopy, and thermodynamic calculations was used to determine the species adding to growing Cu nanowires is Cu­(OH)2–. Cyclic voltammetry was then used to measure the diffusion coefficient of Cu­(OH)2– in the reaction solution. Given the diameter of a Cu nanowire and the diffusion coefficient of Cu­(OH)2–, we calculated the dependence of the diffusion-limited growth rate on the concentration of copper ions to be 26 nm s–1 mM–1. Independent measurements of the nanowire growth rate with dark-field optical microscopy yielded 24 nm s–1 mM–1 for the growth rate dependence on the concentration of copper. Dependence of the nanowire growth rate on temperature yielded a low activation energy of 11.5 kJ mol–1, consistent with diffusion-limited growth