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Institute of Energy and Climate Research

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PV Performance Lab:

Performance, Reliability, Modeling and Prediction

Our research focuses on the characterization and analysis of solar cells and modules. In addition we work on themes such as reliability of various solar module technologies and energy yield of solar modules in various climate zones.


For the basic characterization of solar cells and modules we have constant light solar simulators and flasher systems at our disposal. All of the solar simulators used are of class A (according to DIN EN 60904-9). Several systems are available for the characterization of the external quantum efficiency. We have extensive experience in the characterization of multi-junction devices and are able to measure full area EQE on mini-modules up to 10x10 cm2. Furthermore, we are equipped with setups for a wide range of luminescence and infra-red based characterization methods (e.g. for lifetime imaging or spatially resolved loss analysis).

For the interpretation of measurements a good understanding of physics is paramount. We have extensive experience in the field of device simulations ranging from classical drift-diffusion in (disordered) semiconductors to models suitable for full-sized solar modules. We use a range of opto-electronic device simulators to model small cells. For large area devices we have been actively developing our open-source simulation tool „Photovoltaic Module Simulator (PVMOS)“.

In our virtual Reliability Laboratory we bundle our activities related to reliability of PV modules. These activities include long-term experiments under continuous irradiation to investigate Light-Induced-Degradation (LID) effects, accelerated testing in a climate chamber by exposing devices to light irradiation at elevated temperature and humidity levels. Furthermore, we operate a test stand for PV modules where we measure high-resolution IV characteristics, module and ambient temperature, as well as irradiation intensity and spectrum. During reliability tests we often observe the creation and aggravation of local defects, which are analyzed using state-of-the-art luminescence and infra-red imaging methods. In addition we develop new imaging methods for the fast and quantitative characterization of PV-Modules. Some of these methods may also be used in the field (e.g. Day-Light Luminescence). The activities in the reliability lab rely heavily on our expertise in Performance Analysis, and Device Simulation.

Apart from the characterization of the long-term performance of solar cells we also develop yield models for PV modules. These yield models may be used for analyzing field performance data or for energy yield-prediction. The long-term performance of solar cells depends strongly on climatic conditions. For this reason we use large data-sets with performance data on a wide variety of solar technologies under various climatic conditions (see the PVKlima project). We develop efficient filtering methods for such data sets (e.g. to filter out measurement errors). The filtered data sets are analyzed to characterize the performance, including (meta-stable) degradation effects, and to verify the developed yield models.


Modeling, Prediction: Dr. Bart Pieters

Performance Analysis, Reliability: Dr. Andreas Gerber