Module scale electroluminescence of PV devices: measurements and image quality

Electroluminescence (EL) imaging is a fast and comparatively cheap method for spatially-resolved and non-destructive analysis of photovoltaic (PV) devices. To enable a quantitative use of captured images and support a common standard on EL measurements, this paper focusses on parameters defining the quality of EL images. The image quality is determined and tracked for different EL measurements during various processing steps. It is shown, that although simple post processing methods, e.g. spatial filters, can enhance the visual appearance of EL images, they do not improve the quality of the signal itself.