Crystalline silicon has been the most liked material for solar cell makers since the 1950s, with the material providing supreme conversion stability and efficiency over the alternatives. One thing it doesn’t propose, however, is transparency, but experts in Korea believe they’ve found a way around this constant limitation, with a new method that involves punching carefully positioned holes right through the material.
Transparent solar cells would be a huge blessing to our renewable energy efforts, with the possibility to replace windows in skyscrapers, substitute the sunroofs in cars or maybe act as electricity-generating phone screens.
The quest of this technology has led scientists to discover different solar cell designs, including different materials, with some foregoing efficiency, some long-term stability, and some transparency. Experts at Korea’s Ulsan National Institute of Science and Korean University believe their innovative see-through solar cell would make no such bargains.
“My team members decided that crystalline silicon is the best material to create the glass-like, high-stability, high efficiency and neutral-colored solar cell,” mentions Kwanyong Seo, co-senior author on the paper. “At first thought, it was a silly thought qfor all of us. The problem was that crystalline silicon is not see-through, so in the past, nobody attempted to make transparent crystalline silicon with neutral colors.”
Seo and his team came to this decision after making a big breakthrough. Well, a group of tiny ones, to be exact. To evade the reddish hue and other coloring that has upset the quest for transparent solar cells in the past, the team pierced tiny holes about the size of a human hair in the crystalline silicon to let light to sift through.
These holes are set up in a carefully designed pattern and are undetectable to the human eye. In testing, the transparent solar cell proved long-term stability and conversion efficiency of 12.2 percent. This is out of the box compared to the 20-25 percent efficiencies presented by commercial solar cells, but is a development on some of the other transparent solar cells under construction, too.
The group also tested out the solar cell’s capability as a window. The low-angle light that strikes a vertically oriented, the conventional solar cell can cause falls in the electrical currents of around 30 percent. Favorably, the scientists discovered low-angle light lessened the electrical currents of their solar cells by less than four percent.
“We want to change current windows,” says Seo. “There are many things we have to rise above, such as the regulations by law. We also need to have the mechanical strength and stability to apply our device to replace the existing window in the building.”
From this point, the team is working to make a scaled-up version of the solar cell and is chasing a conversion efficiency of 15 percent. The scientists say the building process is identical to that of traditional solar cells, making the path toward commercialization a little less complicated than it would otherwise be.
The scientists have printed their research in the journal Joule.