Impedance measurements are standard electronic things but usually only for 2 electrodes and electricity. The impedance is measured between the RE and the S.
A two-electrode configuration for the cell is used when precise control of the potential across the electrochemical interface is not critical.
A three-electrode configuration for an electrochemical cell is most common for typical electrochemical applications. A third electrode (the reference electrode) is used to determine the potential across the electrochemical interface accurately Impedance measurements are standard electronic things but usually only for 2 electrodes and electricity.
With a three electrode setup it is possible to selectively probe processes at one of the electrode interfaces, instead of having WE as well as CE processes in your spectrum together. The reason is, that you can measure the potential drop over the working electrode interface alone with the help of the reference. A three electrode measurement might however lead to artifacts in your spectra, so be careful.
Which electrode system (2,3 or 4) is best for taking EIS measurement of hybrid solar cell?And with what electrolyte?