Towards true contactless outdoor luminescence of silicon photovoltaic modules with inhomogeneous small area excitation source

A fast, non-destructive on-site defect detection tool can help to ensure reliable power production of photovoltaic (PV) plants. In particular, it can serve as a cost-effective means for assessing a PV plant's quality and value. Luminescence as a highly sensitive imaging technique can detect local cell damage, series resistance and shunts in solar cells. Typically, outdoor imaging techniques use some sort of modulation of the solar cells' emission. Generally, this requires a physical contact with the module or string. Here, first results obtained from a PL-setup, suitable for fast and fully contactless measurements are presented. The illumination is generated with a small area light source suitable for mobile applications.