Efficiency record for organic solar cells

Solar panels could soon become more eco-friendly thanks to a major breakthrough. Researchers have developed fully organic solar cells, doubling their previous efficiency.

Traditional silicon-based solar cells pose environmental problems at end-of-life. Their recycling is costly and risky due to the substances they contain. Alternatives like perovskite cells, while efficient, also include toxic components.


Scientists are turning to more sustainable solutions, such as fully organic solar cells. These contain no heavy metals and can be safely incinerated. However, their efficiency had previously been limited to about 4%, well below industry standards.

An international team recently made a significant breakthrough. Using a new type of electrode and an innovative lamination technique, they achieved a conversion efficiency of 8.7%. This performance, more than double previous models, paves the way for practical applications.

One major challenge was creating transparent electrodes without damaging underlying layers. Researchers overcame this by developing a PEDOT:PSS-based electrode manufactured at low temperature. This approach preserves the integrity of organic films.

Another key innovation is the lamination method using carbon nanotube electrodes. This technique allows adding layers without altering existing ones. Combined, these advances have achieved record performance for organic solar cells.

These organic solar cells could find applications in sensitive areas like agriculture or wearable devices. Their lightness and flexibility make them ideal for installations where traditional panels would be unsuitable. Researchers now aim to further improve their conductivity.

This study, published in Advanced Functional Materials, marks an important step toward cleaner renewable energy. Organic solar cells could thus play a key role in energy transition by offering a sustainable alternative to current technologies.

How do organic solar cells work?

Organic solar cells use carbon-based materials to convert light into electricity. Unlike silicon cells, they don't rely on inorganic semiconductors. This difference allows for more flexible and potentially less expensive manufacturing.

The conversion process relies on photon absorption by organic materials, generating electron-hole pairs. These charges are then separated and collected by electrodes, producing electric current. The efficiency of this process strongly depends on the properties of the materials used.

Advantages include lightness and the ability to produce cells on flexible substrates. However, the stability and lifespan of organic materials remain obstacles to large-scale adoption.

What is PEDOT:PSS and why is it important?

PEDOT:PSS is a transparent conductive polymer widely used in electronic devices. Its unique combination of electrical conductivity and optical transparency makes it an ideal material for organic solar cell electrodes.

Unlike traditional metals, PEDOT:PSS can be deposited at low temperature, which is crucial for sensitive organic substrates. Its manufacturing doesn't require harsh chemicals, reducing environmental impact.

Despite its advantages, PEDOT:PSS has limitations in terms of conductivity and long-term stability. Current research aims to improve these aspects to enable even higher performance in solar applications.