Perovskite based solar cells have in the last years become a dynamic research field which promises to change the way we will produce electricity in the future. In our research group we work on the deposition of perovskite thin films and their use in solar cells especially tandem solar cells. We are a team of 20 group members who come from a variety of countries, scientific disciplines ad career stages. For spring 2025 we are looking for students who are interested to join us for their master thesis research project. We work experimentally and it can take a while to learn the needed techniques, so we typically aim to have students in our group for at least 9 months. Depending on the requirements of your course this may be best done by combining HiWi time with the master thesis. Our group is based at the Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) and the INATECH Institute of the technical faculty of University of Freiburg. We welcome Freiburg master students from a variety of courses including physics, sustainable systems engineering, chemistry, and other related subjects.
Below is a brief description of some of the projects we are currently offering. If you are interested in doing your thesis with us please contact Dr. Juliane Borchert (juliane.borchert@ise.fraunhofer.de) with a CV, transcript of grades, and some information about the course you are taking.
Topic A) Tailoring the Hole Transport Layer Properties for High-Quality Perovskite Thin Films with the Hybrid Evaporation/Spincoating Method (daily supervision by Oussama Er-raji)
Fully-textured perovskite silicon tandem solar cells are regarded as a strong candidate for next generation high-efficiency photovoltaics. In this architecture, the perovskite film is formed via the hybrid evaporation/spincoating method that allows a conformal coating on large silicon pyramids. However, perovskite films deposited with this method usually suffer from incomplete conversion (residual PbI2 at the perovskite/hole transport layer (HTL) bottom interface), which limits their efficiency. While literature reports have demonstrated that additive engineering can improve the conversion, it often comes at the detriment of stability.
The aim of the master thesis is to enhance the perovskite conversion via an innovative approach based on tuning the properties of the substrate (layer below the perovskite). For this purpose, multiple classes of hole transport layers, including self-assembled monolayers and small molecules, will be selected and tested. Investigation of the HTL layer properties will be performed to evaluate the resulting changes. Furthermore, structural, morphological, and opto-electrical layer characterization of the perovskite absorber will be carried out to gain insight into the influence of the HTL on the formation of the absorber. The different sets of information collected from single layer analysis will be used to improve the efficiency of perovskite single junction solar cells (on ohmic textured silicon substrates).
Topic B) Comparative Analysis of Silicon Substrate Geometry on Perovskite-Silicon Tandem Solar Cell Performance (daily supervision by Mohamed Mahmoud)
We are offering a master’s thesis position to explore the impact of silicon substrate geometry on the performance of perovskite-silicon tandem solar cells using fully evaporated route. Specifically, this project focuses on the effect of changing silicon substrate structures—from planar to nano/micro-textured geometries—on the overall efficiency of solar cells. Textured substrates are known to reduce reflection losses, which could significantly enhance performance, but their implementation in tandem solar cells presents several challenges, such as issues with deposition methods, voltage losses, and varying crystallization dynamics of perovskite layers.
The Borchert Lab 