Solar panels have become the preferred renewable energy capturing method due to their multiple advantages. They are easy to install in most homes, they produce a lot of energy in most areas, they are easy to clean and they are not that cumbersome since they are in the roof of a building which is already underutilized space in most structures. But while this is a good solution in many places, what about all the other surfaces in places like apartment buildings or offices that are made of glass and could collect just as much energy from the sun? We have good news, clear panels do exist, and they might be coming sooner than you think.
The new window solar panels, a twist on traditional methods
Traditional solar panels have a myriad of advantages, but they are not the prettiest to look at, which is why many have attempted other ways to install them. The first attempts to make them translucent enough to be windows were not a success, as the materials did not last long, tinted the windows weird color or were just not practical. But scientists at the Ulsan National Institute of Science and Technology (UNIST) have taken things a step further with a twist on solar cells and are using silicon microwires to collect the energy.
Silicon microwires are tiny, slanted structures embedded in a clear polymer film, and because they are not straight, they are better at grabbing sunlight. When light hits the panel, some of it bounces, but instead of being lost, it is redirected to nearby microwires capturing even more light. Each microwire connects to a layered structure that helps turn that light into usable electricity. The setup includes a p-type polymer layer, an indium-doped zinc oxide (ZnO) layer, and a thin coat of aluminum oxide. This combination of materials keeps energy losses low and boosts electrical performance.
While the results still are a bit less efficient than we would like, 8% efficiency with 10% visible transparency it is actually the best performance ever recorded using silicon. As an additional plus with this method you can tweak how transparent these windows are, from 10% up to 55%, depending on how far apart the microwires are spaced.
The use of silicon also means that the color of these panels is very neutral, as unlike other prototypes of transparent solar cells tend, these do not have a tint that can impact the look of a building. They are practically invisible to the eye, but still doing their job in the background, which is not as important as efficiency, but it is a nice added perk.
While a domestic application is always the first thing we consider, the reality is that with modern architecture that favors entire buildings that are glass paneled, the impact that this new solar panel technology could have is almost immeasurable. Buildings could be so much more efficient and self-sufficient, with their electric needs being met and energy put back into the grid, improving the area’s electricity consumption.
As per usual, the concern now is making these prototypes into a product that can be manufactured at a large enough scale to be profitable and sustainable, which is a long way out. But this time there is a big pro with having to figure out how to get the product to as many places as possible, researchers are optimistic that mass production will help fine-tune the balance between visibility and efficiency, while also making sure these solar cells hold up over time. Plus, unlike some earlier materials like perovskites, which raised concerns about toxicity and long-term stability, silicon is a much safer and more stable choice.