Inside the research on the next generation of solar cells: an interview with Chung Jaehoon

When thinking of the concept of renewable energy, one would imagine a wide array of shiny solar panels glinting on rooftops. But beyond these familiar arrays lies a smaller, more compact technology called photovoltaic solar cells, Though less visible in everyday life, this rapidly advancing field promotes a promising future of sustainable and efficient energy consumption.

In today's interview we spoke with Chung Jaehoon, a researcher at University of Toledo's Wright Center for Photovoltaics Innovation and Commercialization. Chung has shared insights about the promising field of third-generation photovoltaic solar cells, as well as some challenges and the corporates' usage.

Can you first explain your current research field?

So the solar cells I’m working on, commercially available solar cells, are made using a material called silicon. But silicon-based commercial solar cells have a theoretical efficiency limit of about 30%. That’s the maximum efficiency you can reach. To improve upon that, other solar cell technologies exist, but their manufacturing processes are expensive and consume a lot of energy.

Typically, research in universities or research centers focuses on improving existing commercial technologies—to make them better or cheaper. One of the solar cells I’m working on uses a material called perovskite. It has the advantage that it can be applied as a coating, almost like printing.

Traditional silicon solar cells require heating to extremely high temperatures, around 1400°C, to create large single crystals. Then those crystals are cut into smaller sizes—just a few millimeters—to make solar cells. But the problem is that heating to such high temperatures consumes a lot of energy. The next-generation thin-film solar cells can avoid this by allowing a thin coating to be applied.

So the solar cells I’m researching belong to the third generation. The first generation is silicon, the second is thin-film, and the third generation is perovskite solar cells. One challenge is that when solar cells receive light, they also generate heat, like a phone left in the sun, and this heat can reduce efficiency. 

So third-generation cells are still in research—they’re not yet used in everyday life or by companies?

We’re just beginning development and preparing for mass production, and some companies are planning to mass-produce third-generation cells. Since they can be printed, they can be made into flexible solar cells that can attach to windows or surfaces in buildings—what we call building-integrated perovskite—or even potentially placed on cars. Silicon solar panels are heavy, but these perovskite cells can be made lightweight.

Also, some companies are combining third-generation cells with first-generation silicon cells to overcome limitations and improve efficiency. Most companies producing first-generation cells are moving toward “tandem solar cells," which stacks a third-generation cell on top of a first-generation cell, which could theoretically increase efficiency to around 39-40%.

That sounds like an effective strategy. So why did you choose to research this field?

During my PhD, I was originally studying electrochemical catalysis. I also had some interest in solar energy during my master’s, and I was given a great opportunity to collaborate with researchers in the solar field and found it very interesting. I became especially interested in making cells and researching third-generation solar cells because it seemed like a promising field.

What about challenges like financial issues or corporate disinterest?

So far, there haven’t been major problems. Third-generation solar cell research is well-funded in Korea, and our team was producing some of the highest-efficiency cells globally a few years ago. Companies also show strong interest, and many startups in the US are investing.

However, as Trump’s presidency started, US federal funding for energy projects was cut, which did reduce some financial support. While corporate funding continues, some university projects may need to shift focus if federal funding is reduced. If you stay in research, this can become an issue because university and national lab research relies heavily on federal panel funding. If companies decide they won’t invest further, projects stop, and researchers are reassigned. 

So how does that affect third-generation solar cells?

In the US, federal funding was cut, but some labs continue research using corporate funding. But since this is just a domestic policy, research also continues in China, Korea, and Europe using their own funding sources. So overall, the research will continue.

You mentioned mass production earlier—what does that mean?

Mass production means scaling up. In the lab, we make small samples, about 2-inch or 5cm x 5cm. But for commercial use, we need to make much larger sizes. Scaling up involves optimization, which is what we mean by mass production.

Have third-generation solar cells reached the mass-production stage?

Yes, for example, a company in Jincheon, Chungbuk, has set up a production line. Chinese companies have also released prototypes. Other startups are making flexible solar cells using third-generation technology. The advantage is that they can be made cheaply and respond well to indoor lighting. Unlike small solar cells on calculators, these new cells are more efficient and durable.

Have companies tested how consumers will use these cells?

Some companies are developing small indoor solar cells for personal use, while others aim to replace large first-generation silicon panels for energy production. Startups in Canada are selling prototype indoor perovskite cells, but commercial power panels are not yet widely available outside of China. Companies also sell to the personal market, often through platforms like Amazon. People use them for indoor lighting, as these cells can substitute batteries in some cases.

Do you think this research ultimately benefits the environment?

It really does. Using these cells reduces electricity consumption. More importantly, integrating third-generation cells with first-generation silicon cells increases overall efficiency. Current first-generation prototypes reach around 20% efficiency, but combined with third-generation cells, efficiency can exceed 35%, reducing energy usage by roughly 1.5 times per unit area.