Researchers in Switzerland have discovered a new way to make perovskite solar cells more efficient and stable by locking rubidium (Rb) into the material’s structure using lattice strain.
The team from the Swiss Federal Institute of Technology Lausanne (EPFL), led by Dr. Lukas Pfeifer and Dr. Likai Zheng, found that applying strain to the atomic framework prevented rubidium from separating and forming unwanted compounds — a major issue in earlier designs.
This advancement tackles long-standing challenges with wide-bandgap (WBG) materials, which are essential for capturing high-energy sunlight but often suffer from energy loss and instability.
By quickly heating and then cooling the material, the researchers introduced controlled distortion, helping rubidium stay in place and avoid performance-degrading phase separation.
The team also added chloride ions, which improved the material’s internal balance by reducing defects and creating a more uniform ion structure. Tests using X-rays, nuclear magnetic resonance (NMR), and computer simulations confirmed that rubidium was fully integrated, helping reduce energy loss.
The new perovskite material achieved an open-circuit voltage of 1.30 volts, reaching 93.5% of its maximum possible efficiency — one of the best results for WBG solar cells so far. It also showed a strong photoluminescence quantum yield (PLQY), meaning it converts sunlight into electricity more effectively than ever before.
The findings could make perovskite-based solar panels more practical and affordable, especially when paired with silicon in tandem cells. Beyond solar energy, this method could also help improve LEDs, sensors, and other optoelectronic technologies.
The researchers hope their discovery brings us a step closer to using cleaner, more reliable energy sources worldwide.
