Lock-in Thermography: A Versatile Tool for Failure Analysis of Solar Cells

Renewable energy research is currently a major challenge. In recent years, the worldwide production of crystalline silicon solar cells has increased by approximately 30%.[1] New concepts for solar cells and new silicon feedstock are generated in the labs and on the solar cell market. Hence, the need for quality control and failure analysis of solar cells in research and industry has increased rapidly. This article demonstrates the possibilities of lock-in thermography (LIT) techniques for detailed failure analysis of solar cells. Lock-in thermography is well established for failure analysis application in integrated circuits (ICs). Special LIT techniques allow the evaluation of failure positions in ICs with good spatial resolution.[2,3] However, LIT is also a unique tool for characterization of solar cells. Currently, LIT techniques for solar cell research are fully developed and provide a wide range of applications for qualitative and quantitative analysis of solar cell parameters. In this article, a brief description of the lock-in imaging process for solar cells will be given, followed by an explanation of the different modes of LIT and their applications and results.