Detection and analysis of hot-spot formation in solar cells

In this study, infrared thermography (IR) was used to map the surface temperature distribution of solar cells while in the reverse bias mode. It was observed that some cells exhibited an inhomogeneity of the surface temperature resulting in localized heating (hot-spot). Using the scanning electron microscopy (SEM), the structural images of hot-spot areas revealed that hot-spot heating causes irreversible destruction of the solar cell structure. Different techniques were later used to analyze the elemental composition of the different regions of the solar cells. It was revealed that a direct correlation exists between areas of high impurity contaminants and hot-spot heating. Areas with high concentration of transition metals resulted in hot-spot formation. The results of all the samples are presented in detail in this paper.