Cornell University researchers revolutionize solar energy with cutting-edge perovskite science

Solar Materials to Boost Efficiency and Affordability: As the world races toward a future powered by renewable energy, researchers at Cornell University are at the forefront of an exciting solar revolution. With New York state aiming for 70% renewable energy by 2030, a goal that would significantly reduce carbon emissions and dependence on fossil fuels, scientists at Cornell are exploring the next generation of solar materials—ones that promise to be cheaper, more efficient, and easier to produce than traditional silicon-based solar cells.

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At the heart of this transformation is a material that, just a decade ago, was barely on anyone's radar: perovskites. Once considered a mere scientific curiosity, these crystals are now seen as the future of photovoltaics. But despite their promise, challenges remain in scaling up production and ensuring long-term durability. That's where Cornell's interdisciplinary team of engineers, chemists, and materials scientists comes in, working together to turn perovskites from lab-grown wonders into commercially viable solar technology. This comprehensive approach instills confidence in the potential of perovskites.

The Rise of Perovskites: A Material That "Shouldn't Work" but Does

"If you'd asked in 2012, I think many people would have said all of the interesting materials in photovoltaics have been discovered," said Tobias Hanrath, the David Croll Professor in Engineering at Cornell. “Perovskites are a clear example that that's not the case. They came out of nowhere.”

Perovskites, named after Russian mineralogist Lev Perovski, have actually been known since 1839, but their application in solar cells only took off within the last 15 years. Their rapid rise in efficiency—from about 14% in 2013 to 26.7% in 2020—has stunned researchers. Compared to silicon, which has been the industry standard since the mid-20th century, perovskites can be produced more cheaply and with far lower energy input.

Traditional silicon-based solar cells have a well-documented limitation: the Shockley-Queisser limit, which caps their efficiency at around 34%. In reality, most silicon solar cells reach less than 30% efficiency, which has led scientists to seek alternatives.

Perovskites, however, behave in strange and surprising ways. John Marohn, a professor of chemistry at Cornell, describes them as 'a frankly crazy material.' They exhibit a unique combination of liquid-like and solid-like behaviors, as observed in Raman spectroscopy and X-ray diffractometer, respectively. This paradoxical behavior defies conventional logic in materials science, making perovskites a fascinating and promising area of research.

"If you do Raman spectroscopy on one of these perovskites, it looks like a liquid; the atoms are jiggling around like crazy," Marohn explained. “And then you go to the X-ray diffractometer, and it looks like a solid. The atoms are all ordered. So it's totally schizophrenic.”

This paradoxical behavior defies conventional logic in materials science. Silicon solar cells, for instance, must be highly pure to function well. In contrast, perovskites can have a million times more defects and still perform efficiently.

“It just has no right to work this well,” Marohn added.

Beyond Silicon: The Perovskite Advantage

Silicon may be the dominant material in solar panels today, but it has significant drawbacks. Its manufacturing process requires extreme heat and pressure, making it expensive and environmentally taxing. Additionally, silicon is rigid and brittle, making it challenging to integrate into flexible or portable solar applications.

In contrast, perovskites offer a host of advantages:

✅ Lower production costs – Perovskites can be manufactured using simple techniques like inkjet printing and roll-to-roll processing, reducing energy consumption compared to silicon.

✅ More flexible applications – They can be applied to a variety of surfaces, from glass windows to curved rooftops, expanding potential uses beyond traditional solar farms.

✅ Improved efficiency in tandem cells – While perovskites alone may not yet surpass silicon's efficiency, combining them with silicon in tandem solar cells has already exceeded 30% efficiency.

Despite these advantages, perovskites have faced a significant hurdle: stability and scalability. While silicon panels can last 25-30 years, perovskite cells tend to degrade more quickly, especially when exposed to moisture and heat.

Cornell's Breakthroughs in Perovskite Research

Cornell’s interdisciplinary team has been tackling these challenges head-on. Qiuming Yu, Ph.D. '95, 2D lead halide perovskites were developed, where the atoms were stacked like phyllo dough. This structure improves stability while maintaining high efficiency.

Meanwhile, Zhiting Tian, an assistant professor of mechanical and aerospace engineering, has explored thermoelectric applications, using perovskite materials to capture waste heat and convert it into usable energy.

One of the most promising breakthroughs has come from Fengqi You, a professor in energy systems engineering, whose team developed an environmentally friendly method for recycling perovskite solar cells.

In a February 2024 study published in Nature, You's team demonstrated that their recycling method reduces 96.6% of resource depletion and 68.8% of human toxicity impacts compared to simply sending perovskite waste to landfills.

"The inputs—the capital input, the energy, the labor—for making these perovskite products are much lower than silicon," You explained. “For silicon, you need high temperature, high pressure. Not everyone can afford that equipment. But making perovskites is like cooking.”

This breakthrough means that perovskite solar cells can be produced sustainably and affordably, making them a strong candidate for next-generation renewable energy solutions.

Challenges to Commercialization: Can Perovskites Scale Up?

Despite the incredible potential of perovskites, one major roadblock remains: scalability.

Currently, perovskite solar cells only perform well in small, centimeter-scale samples. Manufacturing them at an industrial scale while maintaining consistent quality and durability remains a significant challenge.

Lara Estroff, the Herbert Fisk Johnson Professor of Industrial Chemistry, is leading a Department of Energy-funded project to overcome this issue. Using artificial intelligence, her team is uncovering the ideal chemical formulations and processing conditions for reliably growing durable perovskite films.

"Getting the perovskites commercialized is going to rely on understanding how these materials grow," Estroff explained.

Additionally, Marohn's team is developing new tools to study perovskite charge dynamics at the nanoscale, which could provide further insights into improving stability and efficiency.

"The measurements are hard. The materials are irreproducible," Marohn admitted. “So it's been, frankly, quite a fight to get to where we can make materials and have them be the same every day, every week. But we're finally at that point.”

The 20-Year Horizon: When Will Perovskites Hit the Market?

Historically, it takes about 20 years for a new material to go from lab discovery to mass-market commercialization. For perovskites, that timeline may be shorter.

Already, perovskites have started appearing in tandem solar cells, paired with silicon to boost efficiency. However, a fully perovskite-based solar panel that can compete with silicon on price, durability, and efficiency is still a work in progress.

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For Estroff, the real excitement isn't just about commercialization—it's about discovery.

"I'm doing this because I love understanding how crystals grow,” she said. “I'm glad that I'm doing work that has potential real-world implications and impact. But, yeah, I'm in it for the crystals.”

With Cornell at the cutting edge of perovskite research, the future of solar energy looks brighter than ever. Whether it's in 5 years or 15, the work being done today may soon revolutionize how we harness the power of the sun. Follow Education Post News for more global updates.