Breakthrough in Solar Cells Achieves 33% Efficiency

An international team of researchers has achieved a breakthrough in perovskite-silicon tandem solar cell technology, demonstrating effective passivation methods that could accelerate the commercial adoption of this next-generation photovoltaic technology. The work, published in the journal Science on September 4, 2025, shows how surface treatment can enhance efficiency while making the cells compatible with industrial manufacturing standards.

As reported by Tech Xplore, scientists from King Abdullah University of Science and Technology (KAUST), the University of Freiburg, and the Fraunhofer Institute for Solar Energy Systems successfully passivated upper perovskite cells combined with textured silicon bottom cells featuring large pyramidal structures—a current industry standard. Their passivated tandem solar cells achieved a conversion efficiency of up to 33.1 percent with an open-circuit voltage of 2.01 volts.

Addressing Industrial Manufacturing Challenges

This breakthrough tackles a critical hurdle in commercialization. Standard silicon solar cells use textured surfaces with pyramidal structures to increase surface area and boost efficiency, but such texturing complicates the application of high-quality perovskite layers. Previous successful passivation attempts were largely limited to flat-front architectures, restricting industrial applicability.

“Until now, effective passivation could not be fully implemented on textured perovskite-silicon tandem solar cells; previous successes were mostly limited to flat-front architectures,” said Dr. Usamma Er-Raji, lead author and researcher at Fraunhofer ISE. The researchers achieved this breakthrough by applying 1,3-diaminopropane dihydroiodide to the uneven perovskite surface.

Unique Properties of Perovskite Passivation

The study revealed that perovskite passivation differs from silicon solar cell passivation in a significant way. While silicon passivation affects only surface layers, perovskite treatment impacts the entire absorber layer, enhancing bulk properties throughout its thickness. This pronounced bulk passivation effect improves electrical conductivity and the fill factor of the cells.

“This understanding provides a robust foundation for all future research in this field,” said Professor Stefan De Wolf from KAUST. “It deepens our insight into the processes occurring in the upper cell during light-to-electricity conversion, enabling scientists to leverage this knowledge to develop more advanced tandem solar cells.”