Scientists have managed to use low-energy light to generate electricity in a major breakthrough for solar power.
Invisible light can now be ‘upconverted’ into high energy light, enabling solar cells to capture it and produce electricity. Using this technology, scientists say that we could theoretically obtain far more power from sunlight than ever before, making solar farms and solar panels significantly more efficient.
“The energy from the sun is not just visible light,” explains Professor Tim Schmidt from the University of New South Wales Department of Science, “the spectrum is broad, including infrared light which gives us heat and ultraviolet which can burn our skin.
“Most solar cells, charge-coupled device (CCD) cameras and photodiodes (a semiconductor that converts light into electrical current) are made from silicon, which cannot respond to light less energetic than the near infrared. This means that some parts of the light spectrum are going unused by many of our current devices and technologies.”
Teams across the United States and Australia have used the strategy, called photochemical upconversion, to change invisible infrared light into “more energetic, visible light” so that it can be used to generate electricity.
This is the first time light of this type has been able to be captured, and while the efficiency of the technology needs more work before commercialisation is possible, it bodes well for the future of solar power.
The simple secret ingredient
Previous attempts to harness infrared light for solar power were unsuccessful, only managing to upconvert near infrared light instead.
However, researchers at RMIT University and UNSW University in Australia, and at the University of Kentucky in the US, found that oxygen could be used to help the process. Normally oxygen is a hindrance to these reactions, but at low energies it can be harnessed positively.
“What’s interesting is that often without oxygen, lots of things work well,” says contributing author Professor Jared Cole from RMIT University, “and as soon as you allow oxygen in, they stop working.
“It was the Achilles heel that ruined all our plans but now, not only have we found a way around it, suddenly it helps us.”
Although it may be a while before this technology can be put to widespread use, the breakthrough continues what has been a good year so far for solar power innovation. Double-sided solar panels have begun to be phased in, which are 35 per cent more efficient than standard panels. Elsewhere the largest solar project neared completion in Abu Dhabi, providing record-breaking levels of energy.