Multimodal Characterization of Factors Related to Efficiency and Reliability of Photovoltaic Devices

Photovoltaic (PV) devices convert solar radiation into electricity. This process involves the movement of excess charge carriers generated within the PV device to contact materials that allows current to flow through an external load. There are a variety of factors that can impede the movement or collection of excess charge carriers generated in PV devices related to the structure and composition within the device. Ultimately, this reduces the conversion efficiency and can also impact the long-term power generation potential of PV devices. Mitigation of features related to compromised performance of PV modules and devices requires in-depth understanding of the root causes. Performance issues are typically identified through device or module level observables such as open circuit voltage (VOC), short circuit current (JSC), or fill factor. However, the root causes are often due to features at the micron or sub-micron scale. Thus, connecting compromised PV parameters with the root causes of decreased performance requires a multi-scale multi-technique characterization approach to identify the structure, chemistry, and optoelectronic properties of such features. This contribution focuses on how a variety of characterization techniques, each being effective at a different length scale and focusing on a different material or device property, can be combined in a workflow to reveal the features associated with reduced conversion efficiency and long-term operational stability.