International Team Boosts Stability of Perovskite Solar Cells to 27%

Perovskite solar cells have taken a significant step towards long-term stability and efficiency, thanks to a breakthrough achieved by an international research team. Led by Prof. Dr. Antonio Abate, the group has developed a novel barrier coating that dramatically increases the stability of these cells, which are already known for being cost-effective and generating substantial electrical power per surface area.

The team’s findings, published in the journal Nature Photonics, reveal that the new coating enhances the efficiency of perovskite solar cells to nearly 27%. This marks a notable advancement over the existing silicon market standard. In a rigorous test, the cells maintained their efficiency after 1,200 hours of continuous operation under standard light conditions, demonstrating remarkable durability.

Innovative Coating Technique

The breakthrough stems from the application of a fluorinated compound that acts as an intermediate layer between the perovskite surface and the buckyball (C60) contact layer. Prof. Abate explains, “We used a fluorinated compound that can slide between the perovskite and the buckyball contact layer, forming an almost compact monomolecular film.” This innovative coating effectively isolates the perovskite layer, minimizing defects and energy losses while increasing the structural stability of both the perovskite and C60 layers.

Abate likens the function of this coating to the Teflon effect, where it creates a chemical barrier that prevents defects while still facilitating electrical contact. This development is a culmination of collaborative efforts involving research teams from China, Italy, Switzerland, and Germany, with significant contributions from Guixiang Li, the first author, who is now a professor at Southeast University in Nanjing, China.

Significant Improvements in Performance

The introduction of the new intermediate layer has led to a substantial increase in stability and efficiency. The perovskite solar cells can now achieve a lab-scale efficiency of 27%, slightly surpassing the 26% efficiency recorded without the intermediate layer. Prof. Abate emphasizes the importance of this improvement, noting, “1,200 hours corresponds to one year of outdoor use.” In contrast, a comparison cell lacking the Teflon-like layer saw a 20% drop in efficiency after just 300 hours.

The enhanced coating also offers exceptional thermal stability, enduring 1,800 hours at 85 °C and withstanding 200 cycles between temperatures of –40 °C and +85 °C. The structure of these perovskite solar cells, which features an inverted (p-i-n) configuration, makes them particularly suitable for integration with silicon cells in tandem applications.

Reflecting on the journey to this breakthrough, Prof. Abate recalls, “The idea of using such Teflon-like molecules to form an intermediate film has been on my mind since my postdoctoral days in Henry Snaith‘s lab, who did pioneering research on the perovskite materials. At that time, in 2014, the efficiency was only 15%, declining significantly within a few hours. We have made huge progress.”

The advancements made by this research team not only enhance the performance of perovskite solar cells but also pave the way for the next generation of efficient and stable optoelectronic devices. As the demand for renewable energy sources increases, such innovations will play a crucial role in the transition to sustainable energy solutions.