A research team at Japan’s Tohoku University has developed up to 79 percent transparent solar panels based on monolayer metal and chalcogen semiconductors.
“Transparent solar panels are of great interest because they are not as limited in application as traditional opaque solar panels,” the scientists wrote in an article published in Nature Scientific Reports.
Despite recent breakthroughs in perovskite and organic semiconductor research Despite recent breakthroughs in perovskite and organic semiconductor research, it has not been possible to achieve visible transparency above 70%.
Japanese researchers have chosen to improve the solar cells on the Schottky barrier – a potential barrier that appears in the near-contact layer of a semiconductor adjacent to the metal. The primary materials used were indium tin oxide, the most commonly used transparent conducting oxide, and a monolayer of tungsten disulfide.
Tungsten disulfide is a member of the transition metal dichalcogenide (TMD) family of thin conductors composed of a transition metal and a chalcogen. And they are really thin – only three layers of atoms, the metal layer is located between the chalcogen layers.
Scientists consider transition metal dichalcogenides one of the most promising materials for creating almost transparent solar panels. First, these materials operate in the visible light range. Second, because they are practically transparent to us.
Japanese researchers have tried to improve the contact layer between the components. As a result, using an additional thin layer of tungsten oxide, they achieved a thousand times higher energy conversion efficiency than cells with conventional indium-tin-oxide electrodes. And then, there was a problem with scaling the technology and its practical application.
A simple increase in the number and area of components often leads to a decrease in power. But scientists managed to find “an architectural design suitable for large-scale production of such elements.”
As a result, they have achieved a power of 420 picowatts from a one-square-centimeter solar panel with a transparency of 79 percent. This is the highest value for such a thin element based on transition metal dichalcogenides.