Applications

In the application note AN-EIS-004 on equivalent circuit models, an overview of the different circuit elements that are used to build an equivalent circuit model was given. After identifying a suitable model for the system under investigation, the next step in the data analysis is estimation of the model parameters. This is done by the non-linear regression of the model to the data. Most impedance systems come with a data-fitting program. In this application note, the way NOVA is uses to fit the data is shown.

In this application note, the advantage of recording the raw time domain data for each individual frequency during an electrochemical impedance measurement is described.

Electrochemical impedance spectroscopy (EIS) is a powerful technique which provides information about the processes occurring at the electrode-electrolyte interface. The data collected with EIS are modeled with a suitable electrical equivalent circuit. The fitting procedure will change the values of the parameters until the mathematical function matches the experimental data within a certain margin of error. In this Application Note, some suggestions are given in order to get acceptable initial parameters and to perform an accurate fitting.

A solar cell or photovoltaic cell is a device that converts light energy into electrical energy. Dye-sensitized solar cells (DSC) are currently the subject of intense research in the context of renewable energies as a low-cost photovoltaic (PV) device. Electricity generated from a PV produces zero emissions, is modular, and can produce energy anywhere the sun shines. The standard characterization technique of a PV device consists in the determination of the DC current-voltage curves under different incident light intensities.

DC techniques do not provide any information about the internal dynamics of the PV device. Therefore, additional information can be obtained using time-dependent and frequency-dependent measurements. Electrochemical impedance spectroscopy in particular, offers the possibility to investigate the behavior of the device in the frequency domain under operating conditions, at various light intensities.

Dye-sensitized solar cells (DSC) are currently subject of intense research in the framework of renewable energies as a low-cost photovoltaic (PV) device. To characterize photovoltaic devices, two additional frequency domain methods can be used, based on the modulation of the light intensity. These two methods are Intensity modulated photovoltage spectroscopy (IMVS): measurement of the transfer function between the modulated light intensity and the generated AC voltage, and Intensity modulated photocurrent spectroscopy (IMPS): measurement of the transfer function between the modulated light intensity and the generated AC current.This Application Note illustrates the use of the Metrohm Autolab PGSTAT302N equipped with a FRA32M module, in combination with the Autolab Optical Bench kit to perform IMVS and IMPS characterization of photovoltaic devices.

This application note shows how it is possible with Metrohm Autolab PGSTATs and the Metrohm Autolab Optical Bench, to retrieve information about the mechanism and the kinetics of the back reaction, a side reaction which limits the performances of dye-sensitized solar cells.

In this document, a procedure to calibrate the LED light of the Metrohm Autolab Optical Bench is presented. The procedure can be applied to the single-wavelength LED lights. Calibration is performed in order to relate the LED light intensity to the LED driver current. In this way, it is possible to correct the light intensity values when the distance between the solar cell under test and the LED light is changed. Additonally, the calibration allows the user to perform measurements on solar cells while specifying the light intensity values, instead of the LED driver current.

This Application Note presents the procedure to determine the responsitivity value for calibrating the white lights of the Metrohm Autolab Optical Bench.

The lithium-ion battery market is continuously growing due to the tremendous demand for battery powered consumer products. So-called «NCMs», a mixture of nickel, cobalt, and manganese oxides, have been gathering interest as cathode materials, replacing traditional compounds like cobalt oxides.Quality analysis of the post-sintered materials or recycled batteries can be performed by titration, as demonstrated in this Application Note. A fully automated analysis of the corresponding metals can be performed with OMNIS and its pipetting equipment.