There is a boom in the thin layer solar cell sector; an increasing share of the market is being taken away from the classic silicon solar cells: The European Photovoltaic Industry Association (EPIA) estimates that the worldwide production capacity for this resource-efficient technology will be doubled to more than four gigawatts by 2010. This would mean a photovoltaic market share of 20 percent for the thin layer cells.

This meteoric development can only be realized if the manufacturers are successful in continuing to increase the efficiency of their CIS, CIGS and CdTe cells.

In laboratory tests, small thin layer cells achieve 19.9 percent efficiency. Transferring these peak values to panels in practical use is now the goal, together with continuous improvement. Modern analytical techniques provide valuable contributions here. They enable manufacturers to:

• Monitor the thickness of the layers; online and at-line
• Monitor the elemental contents of the layers; online and at-line
• Identify any impurities in the highly pure starting materials
• Control the quality of soldering metals and wires

As one of the worldwide leading suppliers for optical emission spectrometry (OES) and X-ray fluorescence analysis (XRF), SPECTRO provides the photovoltaic industry with a wide palette of powerful analytical instruments.

The SPECTRO XEPOS is a high-end XRF spectrometer that can determine the contents of all of the important elements between sodium and uranium in every measurement. At the same time, it achieves the accuracy required by the photovoltaic industry for all relevant elements.

The SPECTRO XEPOS is a user-friendly instrument that even non-technical personnel can quickly manage. It has an automatic sample changer for up to twelve samples. In this way it is possible, for example, to take and automatically examine twelve random samples from a panel in order to obtain a representative overview of the elemental contents of the entire panel.

Important for practical use: The SPECTRO XEPOS is not only suited to the examination of CIS, CIGS or CdTe layers but also for the monitoring of many other components, for example, for the analysis of the iron content – the lower the better for the transmission of light – of the solar glass.

The SPECTRO xSORT is a 1.7 kilogram light handheld XRF instrument that is, with its low weight and simple operation, especially suited to at-line analyses in production. The operator simply places the probe on the panel, presses the trigger and immediately receives the conclusive contents of all of the relevant elements such as gallium, selenium, indium, cadmium, tellurium, zinc or iron.

In this way, the SPECTRO xSORT can conduct analyses of representative sample series within just a few minutes. Either one panel can be analyzed at several spots or multiple panels can be controlled in series. The determination is non-destructive; the examined solar cells can be further processed without restrictions.

The ergonomic design of the SPECTRO xSORT has been optimized for long, fatigue-free work. Operation is performed using an integrated PDA that even non-technical personnel can quickly deal with.

In addition to the absorber layer, the quality of the starting materials used is of decisive importance for the efficiency of a thin layer cell. If, for example, the molybdenum in the thin back contact layer is contaminated, it could have an influence on the properties of the entire panel.

Utilization of an optical emission spectrometer using excitation with inductively coupled plasma (ICP-OES) is recommended for the analysis of these types of pure chemicals. These high precision instruments achieve detection limits in the ppb or even ppt range enabling you to reliably identify even minimal trace elements.

For ICP-OES, SPECTRO offers the SPECTRO ARCOS, a high-end instrument that sets standards for measurement accuracy and detection limits while being optimized for economical and efficient operation.

Even stationary metal analyzers have their place in the production processes in the photovoltaic industry: High performance spark spectrometers like the SPECTROMAXx and the SPECTROLAB help panel manufacturers and their suppliers to monitor the contents of solders, wires and other metal components – making their own contribution to the quality and efficiency of thin layer solar cells.

This is a first overview of our solutions for the photovoltaic industry. Our experts are available for any questions about the products available and would be pleased to advise you as to integrating the instruments into your production processes. Contact us at any time via E-Mail or by telephone at +49(0)2821/892-0.