Development of novel imaging techniques for the identification of loss mechanisms in tandem solar cells

• Applicant: Professor Dr. Christoph J. Brabec
• Subject Area: Measurement Systems
• Term: from 2015 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 281813512

Tandem solar cells are of outmost importance due to their inherently higher efficiency as compared to single junction solar cells. However, the significantly larger number of layers is causing higher complexity and requires a much more stringent quality control for tandem cells than for single junction solar cells. In this research project we propose to develop defect imaging methods and routines with the capacity to localize defects in multilayer stacks and to unambiguously assign their occurrence to individual layers. The unique knowledge in which layer a defect is occurring is of outmost relevance for the tandem technology. Most importantly this will allow us to gain deeper insight into the nature of defects which is expected to result in an improved understanding of the material and processing requirements for tandem cells. Further, we expect that the proposed research will lead to measurement methods allowing to probe the functionality of recombination layers based on low doped solution processed semiconductors.We propose to execute this research project in two phases. A first phase of two years is applied for in this proposal. This first phase aims to develop the proper imaging methods at the hand of organic tandem solar cells. If that task is finished successfully, we propose a 2nd period of another 2 years where we want to investigate the functionality and relevance of the imaging techniques for further tandem technologies like the ones based on a-Si:H or GaAs.

• DFG Programme: Research Grants