The breakthroughs making solar panels more efficient

Solar technology has come a long way since New York inventor Charles Fritts created the first solar cell in 1883.

His device wasn’t very efficient – it was only capable of turning a tiny amount of the sunshine it absorbed into electricity, about 1% to 2%. Today’s solar cells – which are typically silicon-based – can convert an average of around 22% of the sunshine they absorb into power. More efficient solar cells mean each solar panel can generate more electricity, saving on materials and the land needed.

Manufacturing silicon solar cells is also an energy-intensive process. Experts warn that renewable power capacity must triple by 2030 to limit global warming to 1.5°C, and solar is predicted to play a major role, so the industry is racing to increase the efficiency of its technology.

Recent breakthroughs have come through perovskites, a family of crystalline compounds that scientists see as a promising technology for solar panels. This is because they can be made to respond to different colours in the solar spectrum, meaning that when combined with another material, such as silicon, they can deliver more power from the same device.

Easier to manufacture, lower cost, and more flexible, perovskites are the focus of increasing research and investment, with organizations around the globe, including in Germany, Saudi Arabia and China, working to find variations that present the best efficiency, highest durability and lowest cost.

In recently published research in the journal Nature, China-based solar module manufacturer LONGi describes advancements made with its perovskite-silicon tandem solar cell, which works by layering an ultra-thin perovskite cell on top of the standard silicon cell.

Through what LONGi calls a “series of technological breakthroughs” that include better structural coupling between the cells and ensuring efficient charge transport, it has “experimentally” achieved a certified efficiency of 33.9%. The company says this is a record for this type of cell and a research milestone – as it exceeds the theoretical limit of single-junction solar cells.

These record-breaking cells are tiny, at 1cm2, and made in laboratories. But researchers say they have big potential and are working to bring these levels of efficiency to commercial-sized cells.

Experts see promise for perovskite in other forms too. Because it can be formulated as an ink, it could be printed onto any object, as well as formed into threads to be woven into fabric, bags or building materials.

Scientists at the University of Oxford have used perovskite to develop a power-generating material that they describe as thin and flexible enough to be applied to everyday objects, such as mobile phones and cars. The material is independently certified to deliver over 27% energy efficiency.

As research continues into the future of solar panels, work will need to be done around challenges including the sustainability of extracting and processing the minerals needed for the technology.

But Oxford experts say this kind of research could ultimately lead to a new industry, which manufactures materials to generate cheap, sustainable solar energy using existing buildings, vehicles and objects.

Other innovations have explored integrating solar generation into our urban environments, including solar windows. Using a transparent solar technology that absorbs ultra-violet and infrared light and turns them into renewable power, these windows could transform skyscrapers into solar farms and have been installed in buildings including in the US and Europe.

Researchers are also working on panels that overcome a key issue with solar by working in the dark or that use the friction generated by rain falling on the panels to create electricity. Meanwhile, AI is being employed to optimize the efficiency of solar farms and quantum technologies have been identified, in the World Economic Forum report Quantum for Society: Meeting the Ambition of the SDGs, as having the power to advance solar cell design.

Regardless of innovation, scientists say solar power is on track to be the world’s dominant power source before 2050. But research to make it more efficient, affordable and sustainable is vital.