New breakthrough in organic solar cell technology doubles their efficiency

Solar energy plays a big role in the fight against climate change. As the world turns to solar power, concerns about the environmental impact of traditional solar panels continue to grow. Today’s most common solar panels use silicon and other materials that contain harmful chemicals.

When these panels are no longer of use, getting rid of them is difficult, expensive, and potentially damaging to the environment. Even newer types of solar cells, like those made with perovskite, contain toxic substances like lead, which also pose disposal challenges.

To solve these issues, scientists have been developing all-organic solar cells—solar panels made entirely from organic, or carbon-based, materials. These cells don’t use metals or other hazardous substances, so they can be safely burned like regular plastic. This makes disposing of them much easier and cleaner. But there’s a catch. These eco-friendly solar cells haven’t been able to reach the performance levels needed for real-world use.

Until recently, their best power conversion efficiency (PCE)—which measures how much sunlight a panel can turn into electricity—was only about 4%. That’s far below the PCE of traditional silicon-based solar panels, which can reach over 27%, and even perovskite panels, which can reach over 26%.

Now, a team of researchers has changed that. Led by Associate Professor Masahiro Nakano from Kanazawa University, the team worked with collaborators from Queen's University at Kingston. Together, they created all-organic solar cells with a PCE of 8.7%. That’s more than double the efficiency of the previous best organic models, and it marks a huge step forward for this technology.

Nakano explains, “We have developed all-organic solar cells with the world’s highest efficiency. This result brings the technology much closer to practical use.”

The new solar cells owe their success to two main innovations. The first involves a new kind of transparent electrode made from a conductive polymer called PEDOT:PSS. In previous attempts, organic electrodes could only be made by using strong acids, bases, or very high temperatures—sometimes above 150°C. These harsh conditions often damaged the thin plastic layers used in organic solar cells.

The new method avoids this issue completely. By heating the PEDOT:PSS to just 80°C, researchers created a film that conducts electricity well without harming the rest of the cell. The result is a thin, flexible electrode with a sheet resistance of less than 100 ohms per square, which is low enough for effective energy conversion.

The second big challenge was figuring out how to build the solar cells without damaging the layers underneath. Organic solar cells are made by stacking several thin layers on top of each other. These layers include light-absorbing materials, conductive materials, and protective films. When researchers tried to add new layers using liquids or solvents, they often ended up ruining the ones below.

To get around this, the team developed a new way to add the top electrode without using damaging liquids. Instead of applying the electrode material directly to the cell, they built it separately on a protective film. Then, they used a technique called lamination to attach it to the top of the solar cell. This approach protected the lower layers and allowed the final product to maintain high performance.

The result of combining these two solutions was a high-efficiency, flexible, and environmentally friendly solar cell.

These new organic solar cells aren’t just laboratory toys. Their flexible and lightweight design opens up many new uses that traditional rigid panels can't handle. For example, they could be placed on curved surfaces like backpacks or tents. They could also be used on farmland, where heavy panels would damage the soil or block too much light. Their soft structure and safe materials make them ideal for use in wearable devices, remote sensors, or even on clothing.

To show how green these solar cells could be, the researchers also tried building them on bioplastic substrates instead of standard plastics. These natural materials break down more easily in the environment and reduce waste. Even when built on bioplastics, the new solar cells still reached a PCE of 8.6%, proving that high performance and environmental safety can go hand in hand.

This progress doesn’t mean the journey is over. The team continues to work on improving the conductivity of organic electrodes. Better conductivity could mean even higher efficiency and broader use. They also aim to make the manufacturing process cheaper and more scalable, so these solar cells can reach the market quickly.

Although the current efficiency still falls behind traditional silicon or perovskite cells, the technology now has a clear path forward. By solving the long-standing issues of material damage and poor conductivity, researchers have opened the door to a new generation of clean energy products that are both sustainable and powerful.

As the world looks for greener ways to power homes, devices, and cities, all-organic solar cells could play a major role. They avoid toxic waste, reduce environmental damage, and offer flexible designs that fit modern needs. The work by Nakano and his team shows that solar energy doesn’t have to come with environmental trade-offs.

Solar power is already a big part of the green energy movement, but making it cleaner from start to finish is just as important as improving performance.

All-organic solar cells may not be the final answer, but they offer a powerful example of how science can push boundaries for both people and the planet. With continued research, the next wave of solar tech could be lighter, safer, and easier to recycle—without losing its shine.

Research findings are available online in the journal Advanced Functional Materials.

Note: The article above provided above by The Brighter Side of News.

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