Degradation of Printed Organic Solar Cells at Extreme Temperatures

In research, organic solar cells (OSCs) have received a lot of attention in recent years because of their non-toxicity, short energy payback times, and high efficiencies reached within only a couple of years of research. Additionally, OSCs are also particularly intriguing because of their easy solution-based manufacturing technique and high absorbance, which allows for thin and flexible solar cells. Especially, slot-die printing is a very promising fabrication approach because it is fast, causes low waste, and is easily upscalable, making OSCs even more viable for future applications like being used in space. Being thin, lightweight, and having a significantly higher power-to-weight ratio compared to commercially used gallium arsenide solar cells, makes them very promising for space applications, reducing production and rocket launch costs. However, the conditions in space are very harsh and these conditions in terms of extreme temperatures, high vacuum, and radiation are supposed to lead to a fast degradation of the OSCs.<br/>Therefore, in this work, we investigate the influence of extreme temperature changes from 0 up to 100 °C on printed OSCs. We optimize the printing process of OSCs and study their degradation process with the help of in-operando grazing incidence small-angle X-ray scattering (GISAXS). GISAXS is a nondestructive technique to examine the morphology and buried structures of thin films. Compared to other scattering techniques, GISAXS measured at a synchrotron benefit from its large probing area and high beam intensity to provide the required time resolution for these investigations. At the same time, we track the performance of the OSCs in vacuum to simulate space conditions. In addition to the electrical characterization and GISAXS measurements, we used techniques such as spectroscopy and real-space imaging to gain further valuable information about the degradation of printed solar cells. The goal of this experimental setup is to gain a deeper understanding of the behavior of OSCs during high-temperature variations. By addressing these issues, we expect to increase the OSCs' longevity and performance and learn more about the upscaling procedure, which will make them a more practical choice for space applications.