While there are statistical studies and macroscopic descriptions of module-level degradation, there is a lack of understanding of the structural, chemical, and electrical properties at the microscopic scale of how these processes occur and how to reduce or eliminate them. The project will study reliability-related defects in major photovoltaic (PV) technologies that include silicon (Si), cadmium telluride (CdTe), and copper indium gallium selenide (CIGS). Researchers will use imaging and microscopy characterization tools along with multi-physics modeling to derive the causes of power-limiting defects that are responsible for potential-induced degradation in Si, metastability and transient degradations in CdTe, and increased degradation due to reverse-bias breakdown in CIGS.
Degradation processes in all three technologies might be reduced or eliminated through correlated measurements of device performance at various scales. This project will draw on module samples from industry partners to develop predictive degradation models and improved testing protocols. The correlated measurement approach will be applied to field-degraded modules, accelerated-lifetime-degraded mini-modules, and in-situ stressing of laboratory scale devices.
Soft costs are high due to uncertainty in module performance in the field. This project aims to find the source of various degradation mechanisms through characterization, microscopy, and modeling and work with manufacturers to improve the long-term reliability of PV. The correlation of microscopic scale properties and measurements with module-level phenomena and observations is a unique contribution of this project that will be leveraged to develop predictive models of degradation mechanisms and rigorous testing protocols for module micro-scale analyses.