Fluoride For Perovskite Solar Cells

• Researchers claim using fluoride to create a protective layer around perovskite solar cells during manufacturing process can help retain latter's efficiency
• They achieved 21.3% efficiency for fluoride lined perovskite solar cells that paves the way for further efficiency gains
• High electronegativity of fluoride ions helps form strong bonds with other elements in the perovskite compound creating a barrier against moisture, light and heat
• Further research is required to improve efficiency and stability of the perovskite solar cells to be able to prove commercial viability

Using small amount of fluoride to perovskite solar cells creates a protective layer that can help solar cells retain 90% of their efficiency after 1,000 hours of operation at extreme testing conditions. This finding of research teams from the Eindhoven University of Technology (TU/e), energy research institute Differ, Peking University and University of Twente, has found its way into science journal Nature Energy.  

"Our cells maintain 90% of their efficiency after 1,000 hours under extreme light and heat conditions. This is many times as long as traditional perovskite compounds. We achieve an efficiency of 21.3%, which is a very good starting point for further efficiency gains," said Research Leader at the Center for Computational Energy Research (CCER), a joint initiative of TU/e and Differ, Shuxia Tao.

According to the researchers, while perovskite holds great promise for solar cells because of its efficiency and affordability, the material is prone to quick degradation because of moisture, light and heat. Applying a fluoride layer for protection during the production process itself can help immensely as fluoride ions exhibit high electronegativity that helps form strong bonds with other elements in the perovskite compound, according to the researchers.

Currently, perovskite solar cells are way off the expected retention rate of 85% of original efficiency for solar cells after 10 to 15 years of working life, but the team expects another 5 to 10 years for these cells to become a commercially viable product. More research needs to be done to further improve their efficiency and stability, as per Tao, who also stressed on a gaining better understanding of the relevant mechanisms at the atomic scale.