Filtro de Aplicações

This bulletin deals with the automated determination of mixtures of HNO3, HF and H2SiF6 in the range of approximately 200-600 g/L HNO3, 50-160 g/L HF, and 0-185 g/L H2SiF6 using thermometric titration.Etch acid mixtures containing HNO3, HF and H2SiF6 from the etching of silicon substrates can be analyzed in a sequence of two determinations using the 859 Titrotherm. The first determination involves a direct titration with standard c(NaOH) = 2 mol/L, followed by a back titration with c(HCl) = 2 mol/L. This determination yields the H2SiF6 content plus a value for the combined (HNO3+HF) contents. The second determination consists of a titration with c(Al3+) = 0.5 mol/L to determine the HF content. For freshly made up mixtures of HNO3 and HF containing no H2SiF6, a linked two-titration sequence is employed. Results from the two determinations are used by tiamoTM to yield individual results for HNO3, HF and H2SiF6.

This Application Note presents the Mott-Schottky measurement, an extension of electrochemical impedance spectroscopy (EIS), on a popular semiconducting material.

Automated determination of the H2SiF6 and HF contents of industrial grade hexafluorosilicic acid.

This Application Note describes the determination of fluoride in silicon etch solutions with thermometric titration.

Determination of the total acids concentration in mixtures of nitric-hydrofluoric acid intended for etching silicon substrates.

Two separate titration sequences are required to analyze the mixture: - titration of the HF content with Al(NO3)3 (the «elpasolite» reaction) - titration of the H2SO4 with BaCl2 followed by titration with NaOH to determine the «total acids» content The HF, H2SO4, and «total acids» contents are converted to a HNO3 equivalent, with the HNO3 content found by subtracting the HF and H2SO4 from the «total acids» content.

Following the addition of caustic soda, hexafluorosilic acid can be determined through back titration of excess hydroxide with hydrochloric acid. Hydrofluoric acid (hydrogen fluoride) is determined by precipitation with aluminum in the presence of sodium and potassium ions. Nitric acid is determined by subtracting the equivalence concentrations of hexafluorosilic acid and hydrofluoric acid from the total acid concentration.

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.

Determination of silicate and hexafluorosilicate (calculated) using anion chromatography with conductivity detection after chemical suppression (see AN S-277) and subsequent UV/VIS detection with post-column reaction. Hexafluorosilicate is hydrolyzed into fluoride and silicate. Both anion concentrations may be used for the calculation of the SiF62- concentration.

This Application Note describes the polarograhic determination of copper in electroplating baths used in the production of thin-film copper indium gallium diselenide solar cells (CIGS cells). The CIGS absorber layer is electrodeposited on a molybdenum-coated substrate. Copper analysis is carried out after dilution of the sample with sulfuric acid as supporting electrolyte.

This Application Note describes the polarographic determination of indium in electroplating baths used in the production of copper indium gallium diselenide thin-film solar cells (CIGS cells). The CIGS absorber layer is electrodeposited on the molybdenum-coated substrate. Indium analysis is carried out after dilution of the bath sample with sulfuric acid as supporting electrolyte.

This Application Note describes the determination of gallium in electroplating baths used in the production of copper indium gallium diselenide thin-film solar cells (CIGS cells). The CIGS absorber layer is electrodeposited on a molybdenum-coated substrate. Gallium analysis using anodic stripping voltammetry (ASV) is carried out after dilution of the sample with sulfuric acid as supporting electrolyte.

This Application Note describes the polarographic determination of selenite in electroplating baths used in the production of copper indium gallium diselenide thin-film solar cells (CIGS cells). The CIGS absorber layer is electrodeposited on a molybdenum-coated substrate. Selenite analysis is carried out after dilution of the sample with sulfuric acid as supporting electrolyte.

This Application Note describes the polarographic determination of cadmium in electroplating baths used in the production of copper indium gallium diselenide (CIGS) or copper indium diselenide thin-film solar cells (CIS). Cadmium sulfide (CdS) from the electrolyte solution is deposited as a thin film on the CIS or CIGS absorber layer via chemical bath deposition (CBD).

This Application Note describes the polarographic determination of thiourea in electroplating baths used in the production of copper indium gallium diselenide (CIGS) or copper indium diselenide thin-film solar cells (CIS). Cadmium sulfide (CdS) from the electrolyte solution is deposited as a thin film on the CIS or CIGS absorber layer via chemical bath deposition (CBD).

This article describes an ion chromatography method for the simultaneous determination of HF, HNO3, H2SO4, short-chain organic acids, and of H2SiF6 in acid texturing baths.

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