LMU researchers have developed a dual molecular strengthening strategy for perovskite solar cells that strengthens grain boundaries, improving both durability and performance.
A research team led by Ludwig-Maximilians-Universität Munich (LMU) in Germany has developed a metal halide-perovskite solar cell that can withstand the high temperatures typical of low Earth orbit (LEO) while offering strong energy conversion efficiency.
The scientists specifically examined the effects of accelerated thermal cycling between -80 C and 80 C. They found that the boosted cells retained approximately 84% of their initial efficiency after 16 extreme cycles, while unmodified cells suffered significantly greater performance losses.
“Such conditions occur not only in laboratory aging tests, but also in operational environments such as LEO, where solar cells on satellites are repeatedly exposed to direct sunlight and then plunged into the cold within a short period of time,” the researchers noted. “Extreme temperatures vary depending on the design and orbit of the spacecraft, and the team selected a representative range for this study.”
The improvement addresses a key challenge in perovskite solar cells: when the perovskite layer and the glass substrate expand and contract at different rates during temperature fluctuations, mechanical stress is built up. This stress is concentrated at the grain boundaries of the perovskite crystals and at the substrate interface, the weakest points of the material. Over time, these localized stresses can cause cracking, delamination and failure, reducing electrical performance and limiting long-term stability.
To overcome these problems, the team developed a targeted molecular amplification strategy. They used α-lipoic acid during film formation, which polymerizes across grain boundaries, reducing defects and strengthening the crystal network. A sulfonium-based derivative was then applied to chemically anchor the perovskite to the substrate, forming an ‘anchored net’ that stabilizes the layer as it expands and contracts under thermal stress.
Together, these measures protect the most vulnerable areas of the cell, improving both durability and efficiency under extreme temperature fluctuations. The device achieved an energy conversion efficiency of more than 26%, which according to the academics is 3% higher than that of a reference cell built without the proposed technique.
“Our work shows that targeted strengthening of grain boundaries and interfaces can significantly improve the mechanical stability of perovskite solar cells,” said Erkan Aydin, lead author of the study. “This brings us one step closer to making this technology viable for real-world applications.”
The new solar cell concept was introduced in “Perovskite solar cells with improved resistance to thermal fatigue under extreme temperature cycles”, published in communication about nature.
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