NEW YORK – This past August, Panasonic Holdings began testing and demonstrating a prototype version of its perovskite photovoltaic material. The prototype is in the form of semi-transparent glass balustrade panels on the balcony of a model house just south of Tokyo. The panels, each measuring nearly a meter in height and nearly 4 meters in width, are just one of the ways Panasonic intends to enter the building-integrated photovoltaics (BIPV) business.
Sandwiching the perovskite between glass means that it can serve as a building’s actual facades and walls while also generating electricity for on-site use or export to the grid, says Yukihiro Kaneko, general manager of Panasonic’s Applied Materials and Technology Center. He adds that Panasonic can change the material’s level of transparency during the fabrication process, according to a customer’s requirements, which can make it suitable for use as windows.
“Regarding perovskite transparency, what is making the difference is the value of the band gap,” says Stefaan De Wolf, an engineering professor at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia. “For silicon of a typical thickness (100 to 150 microns), it will absorb all available visible photons at 1.2 electron-volts. For perovskite, the band gap is usually at least 1.5 eV, allowing transmission of the red part of the spectrum. Moreover, perovskite can be printed in patterns, allowing it to act as a neutral-density filter [for color management].”