Conventional manufacturing processes for perovskite-silicon tandem cells rely on solvents, which present challenges related to the solubility of the raw materials, their toxicity, and the homogeneity and compatibility of individual process steps, among other issues. The Freiburg research team has now succeeded in completely circumventing these problems and developing a more sustainable and potentially more scalable manufacturing process.

The researchers led by Mohamed A. A. Mahmoud and Dr. Juliane Borchert produced the perovskite layer using physical vapor deposition (PVD) and other solvent-free, industrially scalable methods. To better understand crystal formation during deposition and the subsequent annealing process, the research team monitored the process in collaboration with MLU Halle using in-situ X-ray diffraction (XRD). In addition, the researchers investigated the influence of the surface structure of silicon substrates on the formation of the perovskite layer.

As a result, the team succeeded in developing the world’s first perovskite-silicon tandem solar cell manufactured entirely without solvents. This achievement and the new insights into the crystallization processes form an important foundation for the further optimization of the technology and its future industrial implementation.

For further information, see the press release of the University of Freiburg and the Joule article.