10 Mar Making perovskite solar cells more resistant
Perovskite solar cells are considered a promising technology for photovoltaics, as they combine high efficiency with less complex and lower-cost manufacturing compared to conventional silicon cells. A team from the University of Stuttgart together with international researchers reports that they have found a way now to make perovskite solar cells more resistant to environmental influences. “In recent years we have made significant progress in protecting perovskite solar cells against light, heat, moisture, and electrical stress. However, reliably operating them under changing environmental conditions remains a challenge,” says Prof. Michael Saliba, head of the Institute for Photovoltaics (ipv) at the University of Stuttgart. With an optimized material composition, the researchers from China, Germany, the United Kingdom, Spain, Italy, and Switzerland say they have now taken an important step toward solving this issue.
The gold standard among perovskites
The research focuses on triple-cation perovskites, a combination of methylammonium, formamidinium, and cesium. “Triple-cation perovskites are considered by many experts to be the gold standard, as they combine high efficiency with long-term stability and are also reproducible,” explains Saliba, who says he first discovered and systematically investigated this specific material class in 2016. Perovskites are of particular interest because their properties can be precisely tuned through targeted modifications of their crystal structure, enabled by their unique geometry.
Light-switchable molecules to stabilize grain boundaries
To enable the commercialization of these perovskites and establish them as a reliable alternative to silicon semiconductors, further improvements are still required. “We are adjusting very small parameters that can have a large impact,” Saliba explains. One such parameter is the grain boundary. Their instability under heat, light, and moisture makes them the Achilles’ heel of perovskite materials. “Stabilizing the grain boundaries stabilizes the entire solar cell,” says Dr. Weiwei Zuo from Saliba’s research group. To achieve this stabilization, the researchers integrated special light-switchable molecules into the grain boundaries, which change their shape under illumination. This allows them to be dynamically regulated and used as a buffer that absorbs stresses within the material.
High efficiency combined with stability
To test the optimized material, the research team simulated realistic stress scenarios in the laboratory, reflecting the fluctuating daylight conditions and environmental influences that typically occur in operation. According to the researchers, the experiments show that the stabilized perovskite solar cells retain more than 95% of their original performance after two hours of constant UV radiation at 65 °C and after 600 temperature cycles ranging from -40 °C to +85 °C. The cells also achieved an efficiency of around 27%. “Our new material design improves the operational stability and lifetime of perovskite solar cells while maintaining competitive performance, bringing them closer to practical applications,” conclude Saliba and Zuo.
Original publication:
[Zhang, Z., Zhu, R., Li, G. et al.: Photoswitchable isomers to improve grain boundary resilience and perovskite solar cells stability under light cycling. Nat Energy 2026, DOI: https://doi.org/10.1038/s41560-026-01993-z]
Image: Weiwei Zuo