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 Impedance Camera 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.
The measurement results are presented in:
The camera is ideal to observe the real time impedance development of electrochemical sensors.
The Impedance Camera enables to conduct experiments that are complementary to static photocurrent/photovoltage measurements performed, for example, with Photoelectric Spectrometer or a Mini Photoelectric Spectrometer.
The instrument consists of:
Impedance Camera combined with the Electrochemical Head and the Sample Chamber serves as a measurement setup dedicated for the electrochemical samples that needs to be screened from the ambient light and external EM fields.kliknij obrazek, aby powiększyć
The measurement results shown below are obtained for a parallel RC circuit where the resistance was depends on the oscillating illumination intensity.
Nyquist (or Argand) plot presents a real and imaginary part of impedance measured for range of frequencies at various times. One can see the impedance value increases in the middle of the measuring sequence and the impedance semicircles grow in the diameter.
The green color selects the same frequency measurement points in time. If only capacitance was changed, in the RC circuit, all semicircles would be the same size but position of given frequency points would move along a circle.
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