A team of international scientists has made a major breakthrough in solar technology that could accelerate the move toward more powerful and affordable renewable energy.
They have found a way to improve perovskite silicon tandem solar cells—a promising type of solar cell that combines two different materials to capture more sunlight and generate more electricity.
The key lies in a process called passivation, a kind of protective treatment that reduces defects and energy losses in solar cells.
Until now, researchers struggled to make this process work effectively on tandem cells that used the textured, pyramid-shaped silicon layers common in today’s solar industry.
But the new study shows that not only is passivation possible on these textured surfaces, it can also significantly boost efficiency.
Tandem solar cells use a perovskite top cell layered over a silicon bottom cell. This design is exciting because silicon—the workhorse of the solar industry—is nearing its maximum efficiency limit of around 29.4%.
By stacking perovskite on top, scientists can capture parts of the solar spectrum that silicon alone cannot, pushing efficiency far beyond what was once thought possible.
The problem has been that perovskite doesn’t easily coat the textured surface of silicon cells, which are roughened with microscopic pyramids to absorb more sunlight. Creating a smooth, effective passivation layer on these uneven surfaces was a major technical challenge.
The research team, from King Abdullah University of Science and Technology (KAUST), the University of Freiburg, and the Fraunhofer Institute for Solar Energy Systems ISE, has now solved this issue.
They applied a special chemical treatment using a compound called 1,3-diaminopropane dihydroiodide. This successfully passivated the perovskite top cell, even on textured silicon.
The results were striking. The passivated tandem solar cells achieved a record-breaking efficiency of 33.1% and an open-circuit voltage of 2.01 volts. Even more impressively, the scientists discovered that in perovskite cells, passivation improves not just the surface but the entire layer of the material.
This deep effect enhances conductivity and stability, giving the cells a stronger overall performance.
“This is a crucial step forward,” said Prof. Stefaan De Wolf from KAUST. “It gives us a much clearer understanding of how perovskite top cells behave and opens the door to even better designs in the future.”
The research shows strong parallels with the development of silicon solar cells decades ago. In that case, surface passivation was the breakthrough that allowed silicon cells to reach the high efficiencies now standard in the solar industry. Experts believe this discovery could play the same role for perovskite silicon tandem cells, helping them move from the lab to large-scale industrial production.
With efficiency records continuing to climb and manufacturing challenges being solved one by one, perovskite silicon tandem solar cells may soon lead the next wave of solar power—delivering more clean energy from the same amount of sunlight.
Source: KSR.
