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Chinese researchers have built a large-area perovskite photovoltaic panel that retains more than 90% of initial efficiency after more than 850 hours. They used a fully organic hydrophobic salt to modify the top surface of methylammonium-free halide perovskite layers coated with large-area slot dies. Scientists at Nanyang Technological University, China, have fabricated a slot die-coated perovskite solar panel that is reported to offer remarkable efficiency retention. “Large area perovskite solar modules have stability problems due to intrinsic point defects and a mass of surface imperfections introduced during the manufacturing process,” researcher Prem Jyoti Singh Rana explained to pv magazine . The researchers used a fully organic hydrophobic salt known as fluorinated anilinium benzylphosphonate (FABP) to modify the top surface of non-methylammonium (MA) halide perovskite layers coated with large-area slot dies. The salt acts as a molecular lock capable of binding to vacancies of anions and cations, which significantly increases the intrinsic stability of the materials. Not only does it reduce the input of external species such as oxygen and moisture, but it also suppresses the output of volatile organic compounds during thermal stability tests, explain the researchers, who point out that the absence of MA is a decisive factor, due to its tendency to undergo chemical processes that give rise to volatile and electrochemically reactive products. The research group built two different modules with an active surface of 58.5 cm2 and 64 cm2, respectively. The first achieved an energy conversion efficiency of 19.28% and the second of 17.62%. Unpackaged FABP-based devices show excellent thermal stability, retaining 80% and 70% of their initial power conversion efficiencies after 2,700 hours and 1,700 hours at 65ºC and 85ºC, respectively, the researchers explain. “FABP-based unpotted mini-modules show around 80% efficiency retention after 7,500 hours (313 days) under 30% relative humidity (RH). They also remarkably retain over 90% initial efficiency for over 850 hours when measured continuously under light illumination. The scientists presented the module in “ Molecular Locking with All-Organic Surface Modifiers Enables Stable and Efficient Slot-Die Coated Methyl-Ammonium-Free Perovskite Solar Modules. ” , stable and efficient, covered with a slotted die), recently published in Advanced Materials. “Impressively, FABP-treated PSMs retained more than 90% of initial efficiency after more than 850 hours of exposure to continuous sunlight, demonstrating the efficacy of this new generation of non-halide-based passivators in increasing the perovskite stability through strong binding and secondary interaction between organic molecules and perovskite surfaces”, they conclude. |
