The Borchert lab is a group of researchers at the University of Freiburg and Fraunhofer Institute for Solar Energy Systems. Our vision is to develop and understand novel materials for the clean energy solutions of the future. We work on perovskite solar cells with a focus on perovskite-silicon tandem solar cells and perovskite thin-film deposition techniques. At Fraunhofer ISE we form the “Perovskite Materials and Interfaces” group and at the University of Freiburg the “Optoelectronic Thin Film Materials” junior research group. Both groups are interlinked and led by Dr Juliane Borchert.

• NIPHO Conference 2025June 14, 2025
  At the beginning of June Juliane was invited to speak at the International Conference on Perovskite Thin Film Photovoltaics and Perovskite Photonics and Optoelectronics (NIPHO25) taking place at the University of Cagliari in Sardinia. A great opportunity to represent the group and for scientific exchange with others researchers in a delightful setting. Many thanks to theContinue reading “NIPHO Conference 2025”
• New Paper: Photostable Inorganic Perovskite Absorber via Thermal Evaporation for Monolithic Perovskite/Perovskite/Silicon Triple-Junction Solar CellsMay 20, 2025
  We are pleased to announce our latest research advancement demonstrating, for the first time, the successful monolithic integration of an all-inorganic perovskite top cell into a perovskite/perovskite/silicon triple-junction solar cell. In this work, we report the fabrication of CsPbI₂Br perovskite films using thermal co-evaporation at room temperature, completely eliminating the need for any post-deposition annealingContinue reading “New Paper: Photostable Inorganic Perovskite Absorber via Thermal Evaporation for Monolithic Perovskite/Perovskite/Silicon Triple-Junction Solar Cells”
• New Paper: Tuning Self-Assembly of Hole-Selective Monolayers for Reproducible Perovskite/Silicon Tandem Solar CellsFebruary 27, 2025
  Controlling the thickness and orientation of hole-selective self-assembled monolayers (SAMs) has long posed a challenge in the field of perovskite-based solar cells. In our most recent publication, we employ in situ angle-resolved X-ray photoelectron spectroscopy to examine the impact of annealing temperature on the thickness and orientation of the prototypical 2PACz. Our results demonstrate thatContinue reading “New Paper: Tuning Self-Assembly of Hole-Selective Monolayers for Reproducible Perovskite/Silicon Tandem Solar Cells”
• New Paper: Reducing Losses in 3J Solar CellsJanuary 30, 2025
  High open-circuit voltage (VOC) is a key advantage of two-terminal triple-junction solar cells, as the voltages from individual sub-cells add up. To fully harness this potential, it is crucial to identify and minimize voltage losses in each sub-cell. In this study, we identified the high-bandgap perovskite top cell as the primary source of VOC lossContinue reading “New Paper: Reducing Losses in 3J Solar Cells”