A team of international researchers led by King Abdullah University of Science and Technology (KAUST) in Saudi Arabia has developed a new composite material made of acrylate that enhances the performance of solar cells. Adhering the composite material to solar cells deployed in Saudi Arabia for weeks significantly raised the power output and longevity while reducing the electricity consumed by the cells. The study can be read in Materials Science and Engineering: R: Reports.

Solar energy is a major strategic target for green economies in many countries, and more than three quarters of renewable installations are solar cells. But reliable, long-lasting solar energy comes with major challenges. Commercial solar panels convert about 20% of the sun’s rays into electricity. The rest is absorbed as heat or reflected.

Moreover, the heat reduces the performance and lifespan of the solar cells, meaning the cells must be replaced sooner than otherwise. Cooling the solar cells, therefore, is necessary, but cooling systems like fans and pumps need electricity. Passive cooling, on the other hand, does not.

“We specialize in materials that enable passive cooling. These materials are thin and can be placed on different systems that require cooling to operate, like greenhouses and solar cells, without affecting performance,” said KAUST Professor Qiaoqiang Gan, who led the study.

In the new study, which was done through the KAUST Center of Excellence for Renewable Energy and Storage Technologies, Gan and his colleagues prepared a hygroscopic composite made of lithium chloride and sodium polyacrylate that absorbs air moisture at night and releases it during the day. Polyacrylate is a cheap polymer, and the fabrication process needs no hostile chemicals or specialized reagents, unlike other hygroscopic composites used for cooling, further reducing the cost.

While operating for weeks in the Saudi desert, solar cells with this material adhered to them were 9.4 °C cooler than those without the new material. They also showed an increased power output of more than 12% and increased lifespan of more than 200% while reducing their cost of generating electricity by nearly 20%.

In addition to Saudi Arabia, experiments were done in some of the coolest parts of the mainland United States under rainfall to prove that the passive cooling technology works in any environment.

Gan tested the composite material on solar cells provided by KAUST Professor Stefaan De Wolf, whose research team has regularly achieved world records in solar cell performance through their customized designs.

“This work is an excellent example of combining different expertise at KAUST. We tested the new cooling technology on top performing solar cells in multiple environments and saw excellent results in every case,” said De Wolf.