Scientists create low-cost, long-lasting solar cells from wood

The scientific community has turned its attention to organic solar cells, a burgeoning field that promises lower production costs.

[Dec. 15, 2023: JD Shavit, The Brighter Side of News]

Kraft lignin improves the stability in organic solar cells thanks to its ability to form hydrogen bonds that acts as a sort of glue. Thor Balkhed (CREDIT: Thor Balkhed)

In the quest for sustainable energy sources, sunlight has emerged as a prominent contender. Solar energy, particularly from traditional silicon-based solar cells, offers an efficient means of converting sunlight into electricity. However, the energy-intensive and complex manufacturing process of these silicon cells often involves hazardous chemical spills, counteracting their environmental benefits.

In response, the scientific community has turned its attention to organic solar cells, a burgeoning field that promises lower production costs, lightweight designs, flexibility, and diverse applications ranging from indoor use to wearable power sources for personal electronic devices.

Yet, one lingering issue with organic solar cells is their composition, primarily derived from plastics or polymers originating from oil. Despite their organic label, these materials fall short of being truly environmentally friendly. Researchers at Linköping University and the KTH Royal Institute of Technology, however, have taken a significant stride towards enhancing the sustainability of organic solar cells.

In a groundbreaking study published in the prestigious scientific journal Advanced Materials, they have demonstrated that untreated kraft lignin, a prevalent organic material derived from wood, can substantially improve the performance and environmental friendliness of organic solar cells.

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Professor Mats Fahlman, affiliated with the Laboratory of Organic Electronics (LOE) at Linköping University, underscores the overarching goal of their research: "We want to build efficient, reliable, cheap, and environmentally friendly solar cells. This study enables us to show that this is possible and a first step towards replacing today's oil-based materials with wood-based alternatives."

Traditionally, organic solar cells have been plagued by their reliance on petroleum-derived polymers, which detract from their eco-friendly credentials. Nonetheless, these cells have garnered considerable attention due to their cost-effectiveness, portability, and versatility in various applications. As global sustainability concerns intensify, the development of organic solar cells from renewable and biodegradable materials has gained prominence.

In previous studies, researchers explored chemically modified wood-based materials to enhance the stability and reliability of both organic solar cells and solar cells constructed from crystalline perovskite. These studies laid the foundation for the Linköping University and KTH collaboration, which sought to examine the potential of kraft lignin, an untreated form of lignin extracted directly from wood pulp, as a vital component in organic solar cells.

The long-term goal for Mats Fahlman and Qilun Zhang is to build a solar cell almost entirely made from wood materials. (CREDIT: Thor Balkhed)

"We have created a material, or composite, from kraft lignin which is to constitute the cathode interface layer. It turned out that this made the solar cell more stable. The advantage of kraft lignin is that it has the ability to create many hydrogen bonds, which helps to stabilize the solar cell," explains Qilun Zhang, principal research engineer at LOE.

This groundbreaking research demonstrates the feasibility of incorporating wood-based materials into solar cell design, potentially heralding a future where solar cells are predominantly composed of renewable wood resources.

To test the stability and efficiency of the solar cell in the lab an artificial sun is used. (CREDIT: Thor Balkhed)

Organic solar cells, although not as efficient as their silicon counterparts, offer distinct advantages in terms of environmental impact. As Mats Fahlman notes, "Organic solar cells will never be the most efficient. But their advantage is that they are non-toxic, sustainable, and cheap. If they have a 15-20 percent efficiency, that is more than enough for most applications." This attribute positions them as a promising solution for a wide array of sustainable energy needs.

The Potential of Organic Solar Cells

Organic solar cells have already found practical applications, particularly indoors, where they capitalize on ambient light to generate electricity. They have also demonstrated their capability to replace batteries in low-energy devices like sensors, showcasing their adaptability and eco-friendliness. According to Mats Fahlman, the successful integration of kraft lignin into organic solar cells represents a pivotal step towards broader market adoption, potentially enabling scalability for larger applications, such as providing a pure energy supply.

Qilun Zhang, principal research engineer at LOE. (CREDIT: Thor Balkhed)

The synergy of organic solar cells with wood-based materials aligns with the growing global emphasis on sustainability. With traditional silicon-based solar cells, manufacturing processes can involve hazardous chemicals, energy-intensive procedures, and non-renewable materials. Conversely, organic solar cells present a more environmentally conscious alternative, leveraging abundant and renewable organic resources.

Incorporating kraft lignin into the cathode interface layer of organic solar cells addresses several crucial sustainability concerns. Kraft lignin, sourced directly from wood pulp, is a non-toxic, sustainable, and readily available organic material. Its unique capacity to form numerous hydrogen bonds enhances the stability of the solar cell, making it a viable candidate for boosting the performance of these eco-friendly energy generators.

The significance of this research lies not only in the immediate benefits but also in its long-term potential. By introducing wood-based components into the construction of organic solar cells, scientists are paving the way for a future where renewable and biodegradable materials supplant their fossil fuel-derived counterparts. This transition promises to contribute significantly to reducing the environmental impact of solar cell manufacturing and energy production.

Mats Fahlman and his team envision a solar cell industry that is not only efficient and reliable but also ecologically responsible. The successful integration of kraft lignin into organic solar cells exemplifies the path towards achieving this vision. As the world grapples with the urgent need to transition to sustainable energy sources, innovations like these hold the promise of a brighter and greener future.

The journey towards harnessing the full potential of organic solar cells, powered by wood-based materials, is still in its infancy. However, the strides made by researchers at Linköping University and KTH Royal Institute of Technology serve as a testament to the viability of this eco-conscious approach. Their work has opened the door to further exploration and development, aiming to refine the use of kraft lignin and potentially other wood-derived materials in solar cell technology.

As the demand for renewable energy solutions continues to grow, so too does the need for sustainable and environmentally friendly alternatives. The integration of wood-based materials into solar cell technology exemplifies the convergence of nature's resources with human ingenuity to create cleaner and greener energy solutions.

While challenges undoubtedly lie ahead, the prospect of solar cells primarily constructed from wood materials offers a beacon of hope in the journey towards a more sustainable and eco-friendly energy landscape.

As we continue to explore novel approaches to renewable energy, the fusion of nature's resources with cutting-edge technology holds the promise of a brighter and greener world.

For more science and technology news stories check out our New Innovations section at The Brighter Side of News.

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Joshua Shavit
Joshua ShavitScience and Good News Writer
Joshua Shavit is a bright and enthusiastic 17-year-old student with a passion for sharing positive stories that uplift and inspire. With a flair for writing and a deep appreciation for the beauty of human kindness, Joshua has embarked on a journey to spotlight the good news that happens around the world daily. His youthful perspective and genuine interest in spreading positivity make him a promising writer and co-founder at The Brighter Side of News.