Project Name: Operando X-ray Nanocharacterization of Polycrystalline Thin Film Modules
Funding Opportunity: PVRD2
SETO Subprogram: Photovoltaics
Location: Tempe, AZ
SETO Award Amount: $859,253
Awardee Cost Share: $189,564
Principal Investigator: Mariana Bertoni

This project is developing an X-ray-based characterization framework that enables nanoscale module mapping at different length scales for cadmium telluride and copper indium gallium selenide cells under a variety of operating conditions. The project team is using several lab-based mapping and synchrotron-based techniques coupled with the collection of IV curves in custom-designed stages capable of handling different temperatures, atmospheres, and illumination conditions. This work will allow for a better understanding of the nanoscale composition and structural changes that occur during module operation. It will also enable the development of proposed pathways to reduce the rates of the associated degradation, which will enable higher module efficiencies, longer warranties, and lower degradation rates.

The research team combines multi-scale analysis from Arizona State University, Argonne National Laboratory, and SLAC National Accelerator Laboratory on a variety of state-of-the-art thin-film solar cell samples. The analysis includes the correlation of electrical performance with defect characteristics across different length scales. Starting with the characterization of full modules, the team will select multiple areas of interest for the microscopic investigation using laboratory equipment and synchrotron-based X-ray diffraction. The team will then investigate regions of interest by nano-X-ray beam techniques. Measurements will be performed under different conditions including temperature, illumination, and bias voltage. The correlation of multi-dimensional data from a variety of experimental techniques will be completed through machine-learning techniques such as cluster analysis.

This project will help to reduce degradation that occurs in solar modules by gaining a better understanding of the nanoscale composition and structure changes that occur during operation. This will allow for a comprehensive defect model to guide thin film solar cell manufacturers in growing and assembling next-generation modules.