As the world pushes harder to fight climate change, solar energy is becoming more important than ever.
But while solar panels are a clean way to produce electricity, they often contain hazardous materials that can cause environmental harm when it’s time to dispose of or recycle them.
This problem affects not just traditional silicon solar panels, but also newer types like perovskite solar cells, which can contain lead and other toxic substances.
To find a greener alternative, scientists have been working on developing film-like solar cells made entirely from carbon-based, organic materials.
These all-organic solar cells are safer because they can be burned like regular plastics without creating toxic waste, dramatically lowering the environmental and disposal costs.
However, until now, their biggest weakness has been their low efficiency.
Most all-organic solar cells could only convert around 4% of sunlight into electricity—far behind silicon (over 27%) and perovskite (over 26%) solar cells.
Now, a team led by Associate Professor Masahiro Nakano from Kanazawa University, along with researchers from REIKO Co., Ltd. and Queen’s University in Canada, has made a major breakthrough.
They have developed all-organic solar cells that achieve an efficiency of 8.7%—more than double the previous record.
Their findings were published in the journal Advanced Functional Materials.
Two major challenges had been holding back the performance of all-organic solar cells.
First, it was difficult to find organic materials for the transparent electrode—the layer that collects electricity—that were highly conductive but didn’t require harsh chemicals or high temperatures that could damage the delicate organic layers underneath.
The team solved this by using a conductive polymer called PEDOT:PSS, which can be processed at a safer, lower temperature of 80°C and still provides strong electrical performance.
The second challenge was how to stack the delicate layers needed to build the solar cell without damaging them during production. Normally, applying a new layer of material could dissolve or harm the layers beneath it. To get around this, the researchers invented a clever lamination method: they prepared the top electrode layer separately and then gently pressed it onto the device, avoiding any damage.
Thanks to these two innovations, the team created an all-organic solar cell that is not only more powerful but also practical for real-world use. These flexible, lightweight solar cells could be especially useful in sensitive environments like farmland or in wearable technology where traditional rigid panels wouldn’t work well.
The researchers are now aiming to push the efficiency even higher by making the organic electrodes even more conductive, bringing us closer to a future where truly eco-friendly solar power is widely available.
