The instrument is designed for the Time-Resolved Impedance Spectroscopy. Typically, when Impedance Spectroscopy measurements are performed, impedance of a sample is measured subsequently for each frequency applied. However, if a dynamically changing sample is examined, its properties may significantly change during the frequency sweep. A resulted impedance spectrum might be hard to interpret in such a case. The Time-Resolved Impedance Spectroscopy Analyzer takes an entire frequency spectrum with selectable sweep limits in a single shot. All the frequencies are handled at the same time. To observe the time evolution of a sample, many frames may be recorded with a given time interval. The instrument enables to investigate the dynamics of different types of samples, such as electrochemical sensors, materials that changes its properties when exposed to a given agent (light, temperature, catalyst, etc.) and others.

Instrument measures current flowing through the sample and voltage on the sample in response to a voltage signal generated as a superposition of frequencies.
Classic Impedance Spectroscopy (IS) or Electrochemical Impedance Spectroscopy (EIS) assumes that a sample is linear and time invariant (LTI).
However, most electrochemical samples are notoriously both: non-linear and have memory.

 

Non-linear effects
Thus you can explore the following non-linear effects in your sample:

• Higher harmonics generation,
• Intermodulation (when two input frequencies result in a third frequency at the output),
• Electric current rectification (when resistance/impedance of a sample in one direction differs from the resistance/impedance in the other direction of current flow),
• Superposition breakdown (superposition of input frequencies is not preserved in the output).

Sample memory effects

• Time evolution of impedance spectra of a sample under stable ambient conditions reveals if previous measurements affect the next.

Presentations of results
The measurement results are presented in:

• 3D Nyquist (Argand) plot in time,
• Bode plots in time,
• Time evolution plot of an impedance at a given frequency contained in generated signal,
• Difference plots to observe relative changes in time,
• Plots with raw current and raw voltage frames collected.

Applications
The Time-Resolved Impedance Spectroscopy Analyzer is ideal to observe the real time development of impedance of electrochemical sensors. This type of measurements is  complementary to  static photocurrent/photovoltage measurements  performed, for example, with Photoelectrochemical (PEC) Measurement Station:.