Since solar panels became commercially viable for producing much needed and cleaner electricity, we have been working hard to find cheaper and more efficient ways of harnessing the power of the sun. The latest development comes from Stanford University in the United States where they have found that the introduction of microscopic rakes on light harvesting polymer-based cells can improve efficiency significantly.
"This could well be one of the most important developments we have seen in solar cell technology in recent years."
The research has been led by Professor Zhenen Bao, a chemical engineer who works in the Materials and Energy Science Department at Stanford. Although not yet at the commercial manufacturing stage, this new research could see us change from more expensive silicon cells to cheaper polymer-based ones that have, up until now, suffered from an efficiency problem.
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Whilst silicon solar cells are more efficient, they are also a lot more expensive to make, taking some five years to produce enough electricity to offset the initial manufacturing cost. Polymer cells are cheaper and quicker to produce but have the disadvantage of not being as good at producing electricity.
Smaller polymer cells in the lab have produced efficiencies of up to 10% in laboratory conditions but when the technology is taken out into the wider world these levels have tended to drop considerably. Whereas a commercial polymer solar panel will have an efficiency of around 5%, silicon can provide electricity production up to and above 20%.
The potential for polymer cells is quite high as they are also more flexible than silicon cells. For instance, there are versions that can be painted onto conductors and which can be produced at a fraction of the cost of other solar cells. The sky is the limit if scientists can just come up with a more efficient level of electricity production.
How quickly this current microscopic rake development goes from research to the factory floor is a problem that most renewable technology faces, but according to Bao:
"The fundamental scientific insights that come out of this work will give manufacturers a rational approach to improving their processes, rather than relying simply on trial and error. We also expect this simple, effective and versatile concept will be broadly applicable to making other polymer devices where properly aligning the molecules is important."
Finding more efficient ways to produce electricity through solar cells is one of the key factors for renewable energy development on the international stage. Long thought of as the prime research and development arena for new and sustainable technology, a lot of money in the last few years has been put into finding cheaper alternatives to the silicon solar cell.
Along with this drive to find something that can be manufactured and produced at a lower cost is the desire to also reduce the level of toxic waste that is often produced in the manufacturing process. Polymer-based solar cells may offer this opportunity to the industry and help it get over one of the major hurdles that detractors often cite – namely that solar power is not as green as it pretends to be.
With governments being squeezed on budgets and funding and subsidies starting to wane, particularly in the UK, the need for a more viable and cheaper alternative to silicon solar cells has never been greater. The microscopic rakes in Stanford might well be the answer, but we will have to wait some time before they reach the factory floor and subsequently, our rooftops.
