Metrology and Simulation

Our work in the research topic "Metrology and Simulation" is characterized by our expertise in the analysis of solar cells and modules, based on our many years of experience in the fields of technology and metrology and physics. We have detailed knowledge of solar cell structures and physics, metrological concepts and simulation methods, as well as extensive data collections on solar cell parameters. In addition, we use powerful machine learning and artificial intelligence approaches for data analysis.  

Our work focuses on the development of measuring devices and analysis methods to improve materials, solar cells and modules and to optimize inspection and quality assurance in production. We develop solutions together with and for measurement technology and sensor manufacturers, material, cell and module manufacturers, providers of data analysis systems and research institutes.  

We offer solutions in the areas of quality assurance, automated process and production control, measurement method and measurement system development, material and cell analysis, simulation and modeling, as well as automated data analysis and image processing/artificial intelligence. We offer certified solar cell measurements in our independent and accredited calibration laboratory CalLab PV Cells.

Measurement Techniques for Process and Material Analysis

Photolumineszenz-basierte Aufnahme der internen Spannungen (iVoc) in den Teilzellen einer Perowskit-Perowskit-Silizium-Triplesolarzelle.
© Fraunhofer ISE / Graphics: Oliver Fischer, Martin Schubert
Photoluminescence-based internal voltage (iVoc) mapping of the sub-cells of a perovskite-perovskite-silicon triple-junction solar cell.

In order to obtain detailed information for the evaluation of materials for solar cells, we develop new measurement approaches and optimize existing methods. In addition to the precise analysis of silicon materials for solar cells, our analyses also focus on perovskite absorbers and various functional layers, for example.

Our R&D Services Include:

  • Determining the concentration of impurity atoms in silicon (e.g. hydrogen, iron)
  • Determining the charge carrier lifetime and internal voltage (iVoc) in silicon or perovskites as materials in single or multiple solar cells
  • Detailed analyses using photoluminescence and Raman spectroscopy, scanning electron microscopy and other methods
  • Inline analysis for silicon wafers and functional layers

Measurement Method for Cell Analysis

Inline-Solarzellanalyse im PVTEC.
© Fraunhofer ISE / Foto: Dirk Mahler
Inline solar cell analysis at PVTEC.

We conduct comprehensive solar cell testing to thoroughly evaluate solar cell quality and performance. We offer global cell analysis in the laboratory under offline conditions, as well as in-line under industry-compatible conditions, including calibrated measurements for single and multiple solar cells. Spatially resolved, camera-based measurement methods using photoluminescence or thermography enable the evaluation of cell homogeneity and local defects that can reduce global cell performance. We investigate single and multiple solar cells. In addition to silicon solar cells, we are particularly working on perovskite-silicon tandem solar cells and multiple solar cells based on III-V materials.

Our R&D Services Include:

  • Optical-electrical analysis of solar cells
  • Identification of loss channels and efficiency limitations
  • Development of new measurement methods

Measurement Method for Module Analysis

Materialanalyse eine PV-Moduls: Mit der zerstörungsfreien Materialanalyse mittels Raman-Spektroskopie können Aussagen über Degradationsverhalten und Lebensdauer von Modulen und Komponenten getroffen werden.
© Fraunhofer ISE
Life-cycle analysis of modules: With non-destructive analysis using Raman spectroscopy, we can draw conclusions about degradation and durability of modules and components.

We investigate solar cells encapsulated in modules – from small laboratory laminates to large-format PV modules – using a variety of measurement methods. In the Testlab PV Modules, we carry out the tests listed in the IEC and European standards for type approvals. In the CalLab PV Modules, we determine I-V characteristics under STC or NOCT conditions (standard testing conditions, nominal operating cell temperature) as well as temperature and irradiation dependencies.

We develop new measurement methods, for example for perovskite-silicon tandem modules, using LED-based current-voltage analysis.

Our R&D Services Include:

Process Simulation

Simulated etching on the wafer surface
© Fraunhofer ISE
Simulated etching on the wafer surface, taking the immersion process into account.

With the help of process simulations, wet-chemical processes, for example, can be investigated. Processes such as surface reactions, which depend on the flow conditions in the immediate vicinity, are very difficult to access experimentally. Questions such as process homogeneity can be clarified experimentally in extensive experimental designs, but this is both time-consuming and resource-intensive. Simulations in which flows and reactions are combined to investigate the processes at the surface with spatial resolution can help here.

 

Simulation and Modeling of Cells and Modules

Simuliertes Banddiagramm einer Perowskit-Silizium-Tandemsolarzelle unter Kurzschlussstrombedingungen mittels Sentaurus TCAD. Die Tandemstruktur induziert ein starkes elektrisches Feld in der Perowskit-Teilzelle, was zu einer inhomogenen Verteilung der ebenfalls simulierten Anionen und Kationen führt.
© 2024 The Authors. Progress in Photovoltaics: Research in Applications published by John Wiley & Sons Ltd.
Simulated band diagram of a perovskite-silicon tandem solar cell under short-circuit current conditions using Sentaurus TCAD. The tandem structure induces a strong electric field in the perovskite sub-cell, which leads to an inhomogeneous distribution of the simulated anions and cations.

We have detailed approaches for opto-electrical modeling of solar cell structures on silicon, perovskite and III-V basis by means of drift-diffusion modeling and the simulation of entire solar cells.

These opto-electrical simulations take into account the phenomena of optical interference, generation and recombination of charge carriers, charge carrier transport at heterojunctions, tunneling processes, photon recycling and ion migration.

Numerical simulations can significantly accelerate the development process of complex solar cell structures in particular.

R&D Infrastructure

At Fraunhofer ISE, we benefit from this infrastructure for our research and development activities:

CalLab PV Cells

Certified Measurements

Precise measurement of solar cells and modules is of crucial importance in photovoltaics. The photovoltaic calibration laboratory "CalLab PV Cells" at Fraunhofer ISE is one of the leading laboratories worldwide in this field. We measure all types of solar cells and PV modules precisely and reliably in accordance with international standard.

 

Photovoltaic Technology Evaluation Center – PV-TEC

Inline Measurement Technology

For wafer, process and cell inspection, high-performance and highly flexible inline measuring machines are available, which are equipped with extensive, mostly imaging measurement technology for the electrical and optical characterization of wafers and cells and enable the processing of a wide range of wafer/cell formats at high throughput, including wafer-specific measurement data assignment via active or virtual wafer tracking. The systems provide efficient and precise analyses for checking quality and performance. Our customers benefit from meaningful data that supports them in optimizing their solar cell production and creates the data basis for inline loss analysis.

Offline Analysis Methods

Our analysis methods for determining the causes of material and cell losses include global, camera-based and local methods with high spatial resolution. In addition to commercially available measurement systems, we use methods developed and refined in-house that overcome the limitations of conventional approaches. With our innovative analysis techniques, we provide precise insights into the causes of losses, enabling targeted measures to improve components in research and production. 

 

Simulation Methods, Data Analysis

Our work includes the use of powerful simulation tools for detailed modeling of solar cell physics. We work with a simulation software to model entire solar cells and have a large number of further simulation and evaluation tools for quantitative cell analysis. We develop customized approaches for solar cell analysis in the fields of machine learning, automated image recognition and artificial intelligence. These enable efficient data analysis and process optimization, which we offer our customers as tailor-made solutions.

Selected Research Projects

 

KATANA

Calibration of Large-Area Tandem Solar Cells and Modules for Industrial Perovskite Silicon Market Entry

Current Publications on the Topic "Metrology and Simulation"