A group of researchers at the University of California, Los Angeles (UCLA) have built prototypes of a new type of transparent solar cell.
A team at UCLA’s California Nanosystems Institute, led by Professor Yang Yang, says the solar cell that isolates and captures energy from infrared light, which is essentially invisible to the human eye.
While existing thin-film PV technology is flexible than traditional silicon PV panels, thin-film PV modules still have a dark blue colour. This technology means that transparent surfaces – like windows and cell phone screens – could be used to generate electricity.
A sample of the new solar cell on a piece of glass. Photo Credit: UCLA
“[A solar film] harvests light and turns it into electricity. In our case, we harvest only the infrared part,” says Professor Yang, according to the Los Angeles Times. “We have developed a material that absorbs infrared and is all transparent to the visible light.”
The cell is made up of a layer of silver nanowires (about one-thousandth the width of a human hair) and titanium dioxide nanoparticles (acting as an electrode) that can be applied to glass. The conductive material isn’t clear, it is simply very thin.
At the moment, though, this technology (focusing on the infrared spectrum) is less efficient than traditional forms of PV, converting about six percent of the sun’s energy into electricity. But Yang is confident further research will increase efficiency.
“We have to work hard in the lab to expand the coverage of the infrared,” says Yang. “Because infrared is huge, huge energy there, and we only harvest right now less than one-third of the infrared. Our efficiency could double or almost triple in the future. There are some limitations, but we should be able to go to 10% in the next 3 to 5 years.”
”These results open the potential for visibly transparent polymer solar cells as add-on components of portable electronics, smart windows and building-integrated photovoltaics and in other applications,” says Yang of the road ahead.
He also claims that the technology has the capacity to be cheaply mass-produced, since the absorbent material can be printed onto rolls before being applied to glass.
The team’s research has been recently published in the journal Advanced Materials.