Researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) have reported findings that may help improve perovskite-based technology in the entire energy cycle.
The new findings suggest interactions between components of the solar cell itself are responsible for the rapid degradation of the device. More precisely, the titanium oxide layer extracting electrons made available through solar energy – effectively creating an electric current – causes unwanted deterioration of the neighboring perovskite layer. To prevent exactly that, the OIST researchers inserted an additional layer made from a polymer to prevent direct contact between the titanium oxide and the perovskite layers. This polymer layer is insulating but very thin, which means it lets the electron current tunnel through yet does not diminish the overall efficiency of the solar cell, while efficiently protecting the perovskite structure.
“We added a very thin sheet, only a few nanometers wide, of polystyrene between the perovskite layer and the titanium oxide layer,” explained the team. “Electrons can still tunnel cross this new layer and it does not affect the light absorption of the cell. This way, we were able to extend the lifetime of the cell four-fold without loss in energy conversion efficiency”.
The lifespan of the new perovskite device was extended to over 250 hours - still not enough to compete with commercial photovoltaic cells regarding stability, but an important step forward toward fully functional perovskite solar cells.
Earlier this month, researchers from The University of Manchester reported a new method that also makes use of polystyrene particles - to reduce the costs and improve the stability of perovskite-based solar cells.