Perovskite solar cells achieve 27% efficiency with new coating

An international research team led by Helmholtz Zentrum Berlin (HZB) has significantly improved the efficiency and stability of perovskite solar cells by introducing a novel fluorinated interfacial coating between the perovskite layer and the top contact, known as the buckyball (C60) layer. This thin, Teflon-like molecular film acts as a chemical shield, reducing defects and energy losses while enhancing the uniformity and mechanical durability of the C60 layer. As a result, the perovskite cells achieved a power conversion efficiency of nearly 27 percent and maintained this performance after 1,200 hours of continuous operation, equivalent to a full year of natural sunlight exposure. In contrast, cells without the coating lost about 20 percent efficiency after only 300 hours. Beyond efficiency gains, the fluorinated coating improved the cells’ resilience under harsh conditions, withstanding 1,800 hours of thermal aging at 185°F and 200 temperature cycles between -40°F