Fast and Nondestructive Failure Analysis of Organic Photovoltaic Modules for Low-Light Harvesting: Coupling Variable Illumination Measurements to Electroluminescence Imaging

Today, organic photovoltaics (OPV) have reached a maturity level compatible with market deployment. As this technology surpasses traditional solar devices when illuminated by artificial light sources (producing low irradiance), indoor light harvesting represents one of the most relevant application for OPV modules. However, there is a lack of methods to detect defective modules dedicated to such applications. At the single-cell level, it is already established that parallel resistance stands for a figure-of-merit for low-light performance. However, its influence in the case of a series-connected OPV module has not been described yet. Herein, it is reported how parallel resistance discrepancies from cell to cell within an OPV module dramatically affect module performance. Thanks to one-diode modeling, parallel resistance threshold values can be determined for each cell, for a targeted light intensity. In addition, defective cells can be localized by electroluminescence imaging. The usefulness and applicability of the proposed approach is demonstrated on 4-cell and 9-cell modules printed on an industrial tool.