LEIS Localized Electrochemical Impedance Spectroscopy

The VersaSTAT 3F applies an AC voltage to the sample emerged in electrolyte. This "global" voltage generates AC current to flow at the electrode / electrolyte interface. A dual-element probe is positioned in solution close to the surface of the sample. The electrometer measures a differential voltage measure between the two measurement elements as a measure of local voltage-drop in solution. This voltage-drop exists in solution because of current flow from local reactions at the sample, the resistance of the electrolyte and the spatial separation of the dual measurement elements.

The VersaSCAN’s electrometer inputs its measured voltage to the Auxiliary Differential Voltage Input available with the VersaSTAT 3F.

Software integration converts the measured local voltage-drop at the probe to local AC current.

he ratio of local measured current to the global applied voltage gives the localized impedance magnitude and phase shift.

There are two different test methods for the experimentalist to use LEIS to evaluate their samples
A) Chart the local response of a sample from a range of applied AC frequencies in a single location. Data can be viewed in either a Bode or Nyquist representation.
B) Create a series of data maps to characterize an AC response as a function of probe position. Data can be used to create a map, using either Magnitude or Phase as the response
  • Documents +

  • Specifications +

    Potentiostat (VersaSTAT 3F)
    Compliance Voltage ±12V
    Polarization Voltage ±10V
    Current Ranges & Resolution 4nA to 650mA standard; 120fA on 4nA range
    Differential Auxiliary Voltage Option Enabled
    Input Voltage Range ±10.0V
    Input Impedance 10k Ohm
    Gains X1, X5, X10, X50
    Low Pass Filters 1Hz, 10Hz, 100Hz, 1.0kHz, 10kHz, 50kHz, 200kHz
    Notch Filters 50/100Hz, 60/120Hz
    Bandwidth ≥3MHz
    ADC 16 bits resolution, 2µs conversion rate
    ADC Voltage Resolution 305µV, X1 gain, 61µV, X5 gain 1, 30.5µV, X10 gain, 6.1µV, X50 gain
    DC suppression ±10.0V, 16 bits, 305µV resolution
    Probes Dual element probe
  • Options +

    L-Cell VersaSCAN L-Cell
    • Screws into optical table of VersaSCAN
    • Approximately 1 Liter in volume
    • Level adjustment mechanism
    • Accepts large flat samples and 32-mm diameter mounted samples
    • Recommended for all techniques, particularly LEIS, SVET, SKP, SDC, OSP
    VersaCAM VersaCAM
    Long Working Distance Video Microscope
    • Camera:
      • Color
      • Number of pixels: 795 (H) x 596 (V)
      • Minimum illumination 0.02 lx. F1.2
      • Power: 12V DC ±10%
      • CS-mounted or C-mount with provided adapter
    • Lens:
      • C-Mount
      • Manual focus
    • Display:
      • 8 inch color TFT display
      • PAL & NTSC auto selection
      • 640x480 (307,200 pixels) screen resolution
  • Video +

    Watch video demonstrations of the LEIS Localized Electrochemical Impedance Spectroscopy

  • Experiments +

    Point Scan Point Scan sweeps the frequency of the AC signal at a constant probe position. The response then can be viewed as a Bode or Nyquist (Complex) graph. The data is not a map, because the probe is in a constant position.
    Line Scan Line Scan uses a single frequency AC signal and the response is measured at different probe positions. The magnitude and phase are measured and create a map when graphed versus position. The data is not a Bode/Nyquist plot, because it is a single-frequency experiment.
    Area Scan Area Scan is a series of Line Scan experiments in the X-direction at incremented Y-positions.