Impedance spectroscopy is a technique used to measure the resistance of devices. It involves a series of sinusoidal potential signals with equal amplitudes that are applied to electrodes. Normally, the input signal frequencies range from 10 kHz to one MHz. The output current is measured for each of the input potentials.
Impedance spectroscopy is a fundamental technique in electrochemistry and is applied in various fields. It is particularly important in understanding the electrical behavior between an electrode and a solution. It is also used to study electrocatalysis, which involves electrochemical reactions in batteries and fuel cells.
The representation of impedance spectra is complex and is interpreted using a series of equations. In the classical theory of electrical spectroscopy, the electrical impedance of a sample is represented by the sum of its real and imaginary parts, called the Electrical Equivalent Circuit (EEC). Then, a fitting tool is used to find parameter values that closely match the experimental and simulated impedance. Ideally, the fitting parameters correspond to physical quantities of the system.
The impedance spectroscopy technique measures electrical properties in devices and materials. An impedance is the ratio of a voltage and an electrical current to a frequency-dependent current. Using AC voltage, electrochemical impedance spectroscopy measures the electrical current in circuits.
To visualize the impedance of a circuit, an impedance plot is typically created. This plot consists of two logarithmic graphs: a real one containing the impedance and an imaginary one that includes the phase angle. The two sides are then combined to form a Nyquist plot.
In this article, we present a review of the theory behind perovskite solar cells and how impedance spectroscopy can be used to study the kinetics of interface and bulk processes. In particular, we will discuss the relationship between total cell impedance and phase shift.
The Nyquist and Bode plots can be fitted into commercial circuit software. These plots are useful for electrochemistry, corrosion studies, and electrocatalysis. This technique is complementary to other electrochemical techniques. This technique helps distinguish between the electrochemical processes taking place in a particular cell. However, it is important to note that it is not an alternative to electrochemistry. It has a lot of limitations.
