In the relentless pursuit of sustainable energy solutions, solar technology consistently stands out as a beacon of innovation and potential.

One of the most promising avenues in this domain is the development of polymer-based solar cells, prized for their flexibility and thus their immense potential in wearable technology.

Spherical Insights reports that the Polymer Photovoltaic Cell Market is on track to hit USD 1,533.4 Million by 2030, with an impressive CAGR of 25.6%.

The report emphasises, “With the rising significance of renewable energy sources and the government's robust green energy goals, solar energy has emerged as a prime focal point for investors.”

Yet, their widespread application faces a significant roadblock: the toxic solvents involved in their production.

The Game-Changer: Side-Chain Molecular Engineering

Addressing this challenge is the linchpin for enhancing organic solar cell efficiency and unlocking their potential for wearable tech. A cutting-edge study, recently spotlighted in Nano Research Energy, offers a promising solution, and here's an insight into their findings.

A team led by Professor Yun-Hi Kim from Gyeongsang National University in the Republic of Korea has shed light on a novel approach that could be the game-changer: side-chain molecular engineering.

This technique involves tweaking the primary molecule chain by adding specific side chains that can modify its properties. The essence of Kim's insight lies in the understanding of molecular interactions. Kim points out, "Blend morphology of polymer donors and small molecule acceptors are highly affected by their molecular interactions, determined by the interfacial energies between these materials. Enhanced hydrophilicity, achieved through side-chain modifications, promises more favourable interactions."

Building on this premise, the research delved into the possibility of enhancing the polymer donors' water-friendliness (or hydrophilicity). Their approach: introducing oligoethylene glycol (OEG) side chains, taking advantage of the oxygen atoms within, to elevate hydrophilicity.

This seemingly simple alteration had profound implications. When polymer donors and small molecule acceptors have balanced hydrophilicity, they interact more effectively, enabling the use of non-toxic solvents without a dip in solar cell efficiency. The results are impressive – an efficiency leap from 15.6% to an astounding 17.7% with the introduction of OEG side chains.

Pushing the Boundaries: Enhanced Efficiency and Thermal Resilience

But the study did not stop there. Further exploration saw the team working with benzodithiophene-based polymer donors, experimenting with different side-chain combinations, and gauging their effects, and the findings were consistent. Polymers with hydrophilic OEG side chains not only enhance compatibility with small molecule acceptors but also fortify the solar cells' thermal stability.

In rigorous heat tests, these OEG-fortified solar cells outperformed their counterparts, highlighting their potential for large-scale commercial applications. While solar cells with hydrocarbon-only side chains faced significant efficiency degradation and surface irregularities at 120°C, the OEG-enhanced cells displayed robust resilience, retaining a commendable 84% of their efficiency.

The implications of this research are profound. Professor Kim aptly concludes, "Our results offer a blueprint for the next generation of eco-friendly polymer solar cells." This collaborative endeavour, which also involved experts from the Korea Advanced Institute of Science and Technology and the Korea Research Institute of Chemical Technology, lights up a path to a brighter, greener future for solar tech.

In essence, as we look towards a future where wearable tech seamlessly integrates with our daily lives, innovations like these promise to power our way forward sustainably.

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Author:

Charlie Cragg

Content Producer and Writer

Nano Magazine | The Breakthrough