Researchers have achieved a significant breakthrough in polymer solar cell technology by employing a molecular engineering approach to enhance molecular interactions through side-chain modifications. This innovative method eliminates the necessity for toxic halogenated processing solvents, resulting in improved efficiency and stability of these cells. The study, which underscores the advantages of side chains based on oligoethylene glycol (OEG), represents a crucial stride towards the development of environmentally friendly and efficient solar cells suitable for wearable technology.
Polymer solar cells, renowned for their lightweight and flexibility, are ideally suited for wearable devices. However, their wider adoption has been hampered by the requirement for toxic halogenated solvents in their production. These solvents pose environmental and health hazards, diminishing the appeal of these solar cells. Although less toxic alternative solvents exist, they suffer from reduced solubility, necessitating higher temperatures and extended processing times.
This inefficiency has acted as a barrier to the widespread adoption of polymer solar cells. The development of a method that eliminates the need for halogenated solvents could significantly enhance the efficiency of organic solar cells, making them more practical for wearable technology.
In a recently published paper in Nano Research Energy, researchers delineate how enhancing molecular interactions between polymer donors and small molecule acceptors using side-chain engineering can reduce the dependence on halogenated processing solvents.
According to Yun-Hi Kim, a professor at Gyeongsang National University in Jinju, Republic of Korea, “Blend morphology of polymer donors and small molecule acceptors are highly affected by their molecular interactions, which can be determined by interfacial energies between the donor and acceptor materials. When their surface tension values are similar, the interfacial energies and molecular interactions between the donors and the acceptors are expected to be more favorable. To enhance the hydrophilicity of the polymer donors and reduce molecular demixing, side-chain engineering can be a plausible avenue.”
The Role of Side-Chain Engineering
Side-chain engineering involves the addition of a chemical group, known as a side chain, to the main chain of a molecule. These chemical groups in the side chain can significantly influence the properties of the larger molecule. Researchers theorized that incorporating side chains based on oligoethylene glycol (OEG) would enhance the hydrophilicity of the polymer donors due to the presence of oxygen atoms in the side chains. Increased hydrophilicity makes a molecule more water-attractive.
Differences in the hydrophilicity of the polymer donors and the small molecule acceptors can affect their interactions. With enhanced hydrophilicity of the polymer donors and improved interactions between them and the small molecule acceptors, it becomes possible to utilize non-halogenated processing solvents without compromising the performance of the solar cell. In fact, polymer solar cells incorporating OEG-based side chains attached to a benzodithiophene-based polymer donor demonstrated a higher power conversion efficiency at 17.7% compared to the standard 15.6%.
Enhanced Efficiency and Stability
To facilitate a comprehensive comparison of results, researchers designed benzodithiophene-based polymer donors with various side chains, including OEG side chains, hydrocarbon side chains, and a combination of hydrocarbon and OEG side chains. This elucidated the impact of side-chain engineering on the blend morphology and performance of polymer solar cells processed without halogenated solvents.
Kim noted, “Our findings demonstrate that polymers with hydrophilic OEG side chains can enhance the miscibility with small molecule acceptors and improve power conversion efficiency and device stability of polymer solar cells during non-halogenated processing.” In addition to improved power conversion efficiency, polymer solar cells with OEG-based side chains exhibited enhanced thermal stability, a critical factor for scaling up the production of these cells.
The research conducted in this study offers valuable insights for designing polymer donors that can yield efficient and stable polymer solar cells using non-halogenated solvent processing. This advancement holds the potential to revolutionize the field of solar cell technology, making it more sustainable and adaptable for various applications.
Reference: “Polymer donors with hydrophilic side-chains enabling efficient and thermally-stable polymer solar cells by non-halogenated solvent processing” by Soodeok Seo, Jun-Young Park, Jin Su Park, Seungjin Lee, Do-Yeong Choi, Yun-Hi Kim and Bumjoon J. Kim, 24 July 2023, Nano Research Energy.
DOI: 10.26599/NRE.2023.9120088
Contributors to this research include Soodeok Seo, Jin Su Park, and Bumjoon J. Kim from the Korea Advanced Institute of Science and Technology; Jun-Young Park and Do-Yeong Choi from Gyeongsang National University; and Seungjin Lee from the Korea Research Institute of Chemical Technology.
Funding for this research was provided by the Korea Institute of Energy Evaluation and Planning and the Korean National Research Foundation.
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Frequently Asked Questions (FAQs) about Solar Cell Efficiency
Q: What is the main innovation in this research regarding polymer solar cells?
A: The main innovation in this research is the use of molecular engineering, specifically side-chain modifications, to improve the efficiency of polymer solar cells. This approach eliminates the need for toxic halogenated solvents, making the cells more environmentally friendly and practical for various applications.
Q: Why are toxic halogenated solvents a concern in the production of polymer solar cells?
A: Toxic halogenated solvents are a concern because they pose environmental and health risks. Their use in the production of polymer solar cells has limited their widespread adoption due to these hazards and the associated negative impact on sustainability.
Q: What role does side-chain engineering play in this research?
A: Side-chain engineering involves adding chemical groups, known as side chains, to the main chain of a molecule. In this research, oligoethylene glycol (OEG)-based side chains were added to enhance the hydrophilicity of the polymer donors, improving their interactions with small molecule acceptors and enabling the use of non-halogenated processing solvents.
Q: What are the benefits of enhanced hydrophilicity in polymer solar cells?
A: Enhanced hydrophilicity in polymer solar cells leads to improved interactions between polymer donors and small molecule acceptors. This, in turn, allows for the use of non-halogenated processing solvents without compromising the cells’ performance, resulting in higher efficiency and stability.
Q: How does this research impact the future of solar cell technology?
A: This research holds the potential to revolutionize solar cell technology by making it more sustainable and adaptable for various applications. It addresses environmental concerns associated with toxic solvents and enhances the overall efficiency and thermal stability of polymer solar cells.
More about Solar Cell Efficiency
- Nano Research Energy – The journal where the research paper “Polymer donors with hydrophilic side-chains enabling efficient and thermally-stable polymer solar cells by non-halogenated solvent processing” was published.
- Korea Advanced Institute of Science and Technology – The institution with contributors involved in the research.
- Gyeongsang National University – Another institution with contributors to the research.
- Korea Research Institute of Chemical Technology – The institution associated with one of the contributors.
- Korea Institute of Energy Evaluation and Planning – The organization that provided funding for the research.
- Korean National Research Foundation – Another funding organization involved in supporting this research.
5 comments
What’s side-chain thingy? Can someone explain that better? _xD83E__xDD14_
higher efficiency means more power from the sun _xD83C__xDF1E_. Go solar cells! _xD83D__xDCAA_
This is cool stuff! Solar cells gettin’ smarter with science. No more bad solvents! _xD83D__xDE0E_
toxic solvents = bad for planet _xD83C__xDF0D_. Non-toxic = _xD83D__xDC4D_ for environment. We need more of this!
polymer solar cells sound great for wearables. This study shows they can be eco-friendly too. awesome!