Breakthrough in solar-energy coating to power future EVs?

Scientists at Oxford University Physics Department have developed a revolutionary solar power-generating coating that can be applied on everyday objects from buildings over car bodies like future EVs to ‘wearables ‘ like a backpack or even your cellphone’s back. There is no need for silicon-based solar panels anymore, and it’s even more efficient.

The technique for this so-called ‘perovskite coating’ developed in Oxford stacks multiple light-absorbing layers into one solar cell, harnessing a more comprehensive range of the light spectrum and allowing more power to be generated from the same amount of sunlight. At just over one micron thick, it is almost 150 times thinner than a silicon wafer and can be applied to virtually any surface.

Ultra-thin material

The researchers use a crystalline material called perovskite, a mineral formed of calcium, titanium, and oxygen. Gustav Rose discovered the mineral in the Ural Mountains of Russia in 1839 and named it after Russian mineralogist Lev Perovski (1792–1856). Today, perovskite is mainly used in sensors and catalyst electrodes, certain types of fuel cells, solar cells, lasers, memory devices, and spintronics applications.

In Oxford, it is used as a coating base material. “This 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,” the scientists claim.

“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,’ said Dr. Shuaifeng Hu, Post Doctoral Fellow at Oxford University Physics.

Up to 45% of energy efficiency

Solar panels today have around 22% energy efficiency, converting around 22% of the sunlight energy. “We believe that, over time, this approach could enable the photovoltaic devices to achieve far greater efficiencies, exceeding 45%,” Hu adds.

The researchers believe their approach will continue to reduce the cost of solar energy and make it the most sustainable form of renewable energy. Since 2010, the global average price of solar electricity has fallen by almost 90%, making it nearly a third cheaper than that generated from fossil fuels.

Since 2009, the cutting-edge research led by Professor Henry Snaith has been aiming to deliver low-cost, high-efficiency PV technology. Today, 40 scientists are working on photovoltaics at the Oxford University Physics Department, led by Professor Snaith.

Snaith started a UK company called Oxford PV in 2010, a spun out of Oxford University Physics, to commercialize perovskite photovoltaics. He recently started large-scale manufacturing of perovskite photovoltaics at a new 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.