Scientists develop light-absorbing material to generate solar power without silicon

Scientists at Oxford University Physics Department have developed a revolutionary approach that could generate increasing amounts of solar electricity without needing silicon-based solar panels.

Instead, their innovation works by coating a new power-generating material onto the surfaces of everyday objects such as rucksacks, cars, and mobile phones.

This new light-absorbing material is thin and flexible enough to apply to the surface of almost any building or common object. Using a pioneering technique developed in Oxford, which stacks multiple light-absorbing layers into one solar cell, scientists have harnessed a wider range of the light spectrum, allowing more power to be generated from the same amount of sunlight.

The ultra-thin material, using this so-called multi-junction approach, has now been independently certified to deliver over 27% energy efficiency, for the first time matching the performance of traditional, single-layer, energy-generating materials known as silicon photovoltaics. Japan’s National Institute of Advanced Industrial Science and Technology (AIST), gave its certification prior to publication of the researchers’ scientific study later this year.

“During just five years experimenting with our stacking or multi-junction approach we have raised power conversion efficiency from around 6% to over 27%, close to the limits of what single-layer photovoltaics can achieve today,” says Dr Shuaifeng Hu, Post Doctoral Fellow at Oxford University Physics. “We believe that, over time, this approach could enable the photovoltaic devices to achieve far greater efficiencies, exceeding 45%.”

This compares with around 22% energy efficiency from solar panels today (meaning they convert around 22% of the energy in sunlight), but the versatility of the new ultra-thin and flexible material is also key. At just over one micron thick, it is almost 150 times thinner than a silicon wafer. Unlike existing photovoltaics, generally applied to silicon panels, this can be applied to almost any surface.

‘By using new materials which can be applied as a coating, we’ve shown we can replicate and out-perform silicon whilst also gaining flexibility. This is important because it promises more solar power without the need for so many silicon-based panels or specially-built solar farms,’ adds Dr Junke Wang, Marie Skłodowska Curie Actions Postdoc Fellow at Oxford University Physics.

The researchers are among 40 scientists working on photovoltaics led by Professor of Renewable Energy Henry Snaith at Oxford University Physics Department. Their pioneering work in photovoltaics and especially the use of thin-film perovskite began around a decade ago and benefits from a bespoke, robotic laboratory. Their work has strong commercial potential and has already started to feed through into applications across the utilities, construction, and car manufacturing industries. 

Oxford PV, a UK company spun out of Oxford University Physics in 2010 by co-founder and chief scientific officer Professor Henry Snaith to commercialise perovskite photovoltaics, recently started large-scale manufacturing of perovskite photovoltaics at its factory in Brandenburg-an-der-Havel, near Berlin, Germany. This is the world’s first volume manufacturing line for ‘perovskite-on-silicon’ tandem solar cells.