Solar energy breakthrough could reduce need for solar farms

Scientists at Oxford University Physics Department have developed a revolutionary approach which could generate increasing amounts of solar electricity without the need for silicon-based solar panels. Instead, the innovation works by coating a new power-generating material onto the surfaces of everyday objects like rucksacks, cars and mobile phones. 

The new light-absorbing material is, for the first time, 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, the group has harnessed a wider range of the light spectrum, allowing more power to be generated from the same amount of sunlight. 

The 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 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. 

Dr Shuaifeng Hu, Postdoctoral Fellow at Oxford University Physics said:

“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. 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.”

Dr Junke Wang, Marie Skłodowska Curie Actions Postdoctoral Fellow at Oxford University Physics said:

“By using new materials which can be applied as a coating, we have shown we can replicate and out-perform silicon while also gaining flexibility. This is important because it promises more solar power without the need for silicon-based panels or specially-built solar farms.

“We can envisage perovskite coatings being applied to broader types of surface to generate cheap solar power, such as the roof of cars and buildings and even the backs of mobile phones. If more solar energy can be generated in this way, we can foresee less need in the longer term to use silicon panels or build more and more solar farms.”

The researchers believe the approach will continue to reduce the cost of solar and also make it the most sustainable form of renewable energy. Since 2010, the global average cost of solar electricity has fallen by almost 90%, making it almost a third cheaper than that generated from fossil fuels. Innovations promise additional cost savings as new materials, like thin-film perovskite, reduce the need for silicon panels and purpose-built solar farms. 

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