In-situ X-ray Nanocharacterization of Defect Kinetics in Solar Cell Materials

In-situ X-ray Nanocharacterization of Defect Kinetics in Solar Cell Materials In-situ X-ray Nanocharacterization of Defect Kinetics in Solar Cell Materials Scope of work The performance of industrial solar cells is often regulated by inhomogeneously distributed nanoscale defects. These defects can take the form of impurities, microstructural misalignments and secondary phases -- the majority of which are created during the processing of the solar cell. In many photovoltaic (PV) materials systems of technological importance today, including crystalline silicon and thin film technologies, processing occurs under controlled atmospheres at elevated temperatures (up to 1800C), where diffusion processes govern the final defect distribution and concentration. The objective of this research project is to design, build and utilize an X-ray in-situ microscopy capability at the Advanced Photon Source (APS) for the study of the different kinetic pathways in which defects relax to their equilibrium values, under actual processing and operating conditions. Synchrotron-based nano-X-ray fluorescence microscopy (n-XRF), coupled with X-ray absorption microspectroscopy (XAS) are ideal tools for investigating elemental and chemical properties of bulk materials at the sub-micron scale with very high sensitivity to elemental contaminants. Based on x-ray fluorescence micro/nanoprobe at the APS, the collaborative research team will design and implement an in-situ sample stage to perform spectromicroscopy on the sub-micron level with the capabilities of heating, atmosphere control and monitoring of electrical response. The unique expertise of the group members will help address design challenges like monitoring and control of microscopic vibrations and macroscopic thermal drift. The in-situ stage will have the potential to be used for a wide range of materials systems. However, in the context of this FOA, the team will apply their previous knowledge in X-ray science and Photovoltaics to address pressing, industrially-relevant challenges, including: (1) Reducing the cost of metallization in crystalline silicon a study of the potential induced degradation behavior of Cu- and/or Ni- metalized cells versus the market standard Ag-metalized cells. (2) Understand the effects of the electromigration of species in thin films (e.g., Cu in CIGS, As in GaAs:Zn/GaAs:Se) a study of the metastable effects observed in CIGS