When you imagine a solar cell what usually comes to mind is a rigid block. But what if solar cells could be fully foldable? Then, a bunch of new applications would open up for them from wearables to gadgets.
Now, engineers at Pusan National University in Korea have developed exactly this type of solar cell. But achieving it was no easy task.
“Unlike merely flexible electronics, foldable devices are subject to much harsher deformations, with folding radii as small as 0.5 mm. This is not possible with conventional ultra-thin glass substrates and metal oxide transparent conductors, which can be made flexible but never fully foldable," said in a statement Professor Il Jeon of Pusan National University, Korea.
To build their new flexible solar panels, the researchers used single-walled carbon nanotube (SWNT) films because of their high transparency and mechanical resilience. The scientists then embedded the conducting layer into a polyimide (PI) substrate.
Finally, they also introduced small impurities into the SWNT-PI nanocomposite layer so that more charge could be generated for a given amount of current. The result was an incredible solar panel never-before-seen.
It measures only 7 micrometers thick. But don't let its thinness fool you. The composite film exhibits exceptional resistance to bending. Test panels were able to withstand over 10,000 folding cycles without breaking.
And they produced almost 80% transparency, and a power conversion efficiency of 15.2%, the most ever achieved in solar cells using carbon nanotube conductors.
“The obtained results are some of the best among those reported thus far for flexible solar cells, both in terms of efficiency and mechanical stability," said Jeon.
With the rise of foldable phones on the market, we cannot help but think we might be seeing some solar ones in the near future. And this is just the beginning of this technology's potential applications.
The research is published in Advanced Science.