If there is anything silicon stands out for, besides its solar energy capturing properties, it is because of its rigidity. This feature had so far kept this material in the background for use as a portable renewable energy source. But what if the rigid could become flexible? This was achieved by a scientific team from the King Abdullah University of Science and Technology (KAUST), who designed new silicon solar cells that are no longer flexible, but ultra-flexible. So much so that they can even warp in a zigzag shape.
The above, of course, remains in use thereafter and without loss of conversion efficiency, an aspect for which silicon stands out and well compared to other alternatives. However, when the scientific community tried to find the formula to soften the stiffness of this material and thus take advantage of it for flexible electronics, it hit the bone. Attempts to create thin-film silicon cells have failed because a drop in performance below 250 microns has been compromised.
For this reason, KAUST gave a twist to the idea. “At this thickness, there is no way to get flexible silicon solar cells”The head of the investigation, Muhammad Hussain, indicates the starting point of his work. With this in mind, scientists set to work to find a new architecture that offered what they were looking for: resilience and performance. In this last area 17% efficiency was achieved, which also adds to the stability shown before 1000 bending cycles.
To get there, as explained from KAUST, new ultra-thin silicon segments have been created, connected by screen-printed aluminum contacts. Located at the back of the cells, this incorporation optimizes absorption, while promoting modifications in the silicon so that it can adopt a multitude of configurations, especially in zigzag, without breakage or loss of efficiency.
Another problem was essential to materialize this advance. It is none other than the thickness. To play with and maintain performance, the experts recorded a small part of the solar cell in 140 micron bands, while the rest of the cell was kept at 240. As Hussein was already moving forward, this was achieved. “Record levels for efficiency and curvature of silicon solar cells”, according to Rabab Bahabry, who was also involved in the project.
The results of this work, which have just been published, overcome a challenge from those that remained unanswered to open up new possibilities for silicon and the use of solar energy in general. And that’s it, at a time when the demand for sustainable energy solutions for portable and implantable devices, or for panels integrated into vehicles, it is essential to be able to draw one of the most efficient materials for these technologies. “Our approach can adapt to the Internet of Things and respond to a wide range of applications”, advance from KAUST.