Scientists at Oxford University’s Physics Department have developed an approach which could generate increasing amounts of solar electricity without the need for silicon-based solar panels.
It works by coating a new power-generating material onto the surfaces of everyday objects like rucksacks, cars and mobile phones. The light-absorbing material is, for the first time, thin and flexible enough to apply to the surface of almost any building or common object.
The technique developed in Oxford, which stacks multiple light-absorbing layers into one solar cell, means that a wider range of the light spectrum is harnessed, allowing more power to be generated from the same amount of sunlight.
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.
Dr Shuaifeng Hu, Post Doctoral 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.
The researchers believe their 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.
