If there is something for which silicon stands out, in addition to its properties for capturing solar energy, it is because of its rigidity. This characteristic had for the moment kept this material in the background for use as a portable renewable energy source. However, what if the rigid could become flexible? This is what a scientific team from the King Abdullah University of Science and Technology (KAUST) has achieved, which has designed new silicon solar cells that are no longer flexible, but ultra-flexible. So much so, that they can even deform in a zigzag.
The above, of course, remaining in use later and without losses in conversion efficiency, an aspect for which silicon stands out and much over other alternatives. However, when the scientific community has tried to find the formula to soften the rigidity of this material and, thus, take advantage of it for flexible electronics, it has hit bone. Attempts to create thin-film silicon cells were unsuccessful since, dropping below 250 microns, performance was compromised.
For this reason, KAUST has given the idea a spin. “At that thickness, there is no way to get flexible silicon solar cells, “ says the head of the research, Muhammad Hussain, the starting point of his work. With this in mind, the scientists set to work to find a new architecture that offered what they were looking for: resilience and performance. In this last field , an efficiency of 17% has been achieved, which is also added to the stability shown before 1,000 curvature cycles.
To get there, as explained by KAUST, new ultra-thin silicon segments have been created that are connected with aluminum contacts printed with screen printing. Located at the back of the cells, this incorporation optimizes absorption, while favoring modifications to the silicon so that it can adopt a multitude of configurations, including zigzag, without breaking or losing efficiency.
Another issue has been key to materializing this advance. This is none other than the thickness. To play with it and maintain performance, the experts recorded a small portion of the solar cell in 140-micrometer strips, while the rest of the cell remained at 240 microns. As Hussein was already advancing, this achieved “record levels for the efficiency and curvature of silicon solar cells, ” explains Rabab Bahabry, who also participated in the project.
The results of this work, which have just been published, overcome one of those pending challenges to open up new possibilities for silicon and the use of solar energy in general. And it is that, at a time when the demand for energy sustainable solutions for portable and implantable devices, or for integrated panels in vehicles is growing , being able to pull one of the most efficient materials for these technologies is key. “Our approach can adapt to the Internet of Things and respond to a wide range of applications” , advance from KAUST.