A research team in Korea has developed a new solar cell technology, recently published in Joule, that could end up replacing our normal windows. They developed a neutral-colored transparent crystalline silicon (c-Si) substrate using a 200-um-thick wafer that is known to be intrinsically opaque.
Common existing solar cells have a reddish hue and a lower efficiency. These windows are designed to enable the transmission of all incident visible light through the substrate. They accomplished this by strategically punching tiny holes around the size of a human hair on the crystalline silicon wafers, which then allows light to pass through without coloring, and are undetectable by the human eye.
Kwanyong Seo, of the Ulsan National Institute of Science and Technology (UNIST), co-authored the project:
My team members concluded that crystalline silicon is the best material to develop the glass-like, high-efficiency, high-stability, and neutral-colored solar cell. At first thought, it was a crazy idea for all of us. The problem was that crystalline silicon is not transparent, so before us, nobody tried to make transparent crystalline silicon with neutral colors. Current solar cells need space, on the ground or enough space on the roof, the roof ratio is getting smaller and smaller compared to the window area.
This is why these see-through solar cells are an ideal material for turning windows into solar panels, said Seo. They were able to generate a power conversion efficiency (PCE) up to 12.2%, which is the ratio of incident light power to output electrical power. Now that they’ve successfully created the next-generation colorless transparent photovoltaics, the next step is increasing the efficiency to 15%.
Seo goes on to explain more; “We want to replace current windows. There are many things we have to overcome, such as the regulations by law. We also need to have the mechanical stability and strength to apply our device to replace the current window in the building.”
The transparent solar cells are expected to be easier for commercialization because the fabrication process would not need much altering from what is common today. They believe this technology can also be applied to many different products including mobile devices as a power source. As Seo says, this silicon substrate is a very popular material in the semiconductor industry.
