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NREL Advances Perovskite Solar Cell Durability with New Ionic Salt-Based Layer
May 12, 2025
A groundbreaking study by the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) has demonstrated a major leap in perovskite solar cell (PSC) performance and stability by replacing the conventional fullerene (C60) electron transport layer (ETL) with a newly synthesized ionic salt known as CPMAC (phenylmethanaminium chloride). Published in the journal Science, the study underscores how this innovative substitution improves power conversion efficiency (PCE), mechanical durability, and long-term reliability—key factors for commercial viability.
Perovskites, celebrated for their light absorption and semiconductor properties, have shown promising lab-scale efficiencies but have struggled with long-term stability under light and heat. The new CPMAC compound, derived from C60 but with a methyleneammonium head group, allows tighter molecular packing and stronger bonding at the ETL interface. This enhances interfacial mechanical strength by nearly three times compared to conventional C60-based ETLs.
PSCs using the CPMAC layer achieved a record PCE of 26.1%, surpassing the 25.5% recorded with traditional ETLs. More impressively, devices retained over 98% of their efficiency after 2,100 hours under continuous one-sun exposure at 65°C, while C60-based cells showed 5?gradation in 1,500 hours at 85°C. In mini-module tests with a total area of 6 cm², CPMAC-enabled cells reached a 23% PCE and showed less than 9?gradation after 2,200 hours at 55°C.
The research also utilizes an inverted architecture, known for thermal stability and compatibility with tandem solar cells, potentially paving the way for more durable and efficient commercial modules. The advancement aligns with NREL’s broader goals—outlined in May 2024—to boost efficiency, scalability, and reliability in solar technology, with a focus on hybrid tandem module design for real-world deployment.