A domestic research team has developed a high-efficiency perovskite solar cell with a lifespan more than tripled. They succeeded by developing a material that can replace an additive that boosts efficiency but shortens lifespan.
Research teams led by Professors Yang Chang-deok and Shin Seung-jae of the Department of Energy and Chemical Engineering at Ulsan National Institute of Science and Technology (UNIST) and Professor Min Han-ul of Korea University said on the 22nd that they developed a solid additive, 4CP, and applied it to perovskite solar cells to achieve a high power conversion efficiency of 26.2% and long-term stability of 3,000 hours. The findings were published in the international journal Nature Energy on the 10th.
tBP (4-tert-butylpyridine) is an additive added to evenly disperse lithium ions inside a solar cell, increasing the efficiency with which the cell converts sunlight into electricity. However, because it is in liquid form, it volatilizes easily at high temperatures, and in the process fails to properly hold lithium ions, creating byproducts or tiny holes (pinholes) inside the cell. This is a major cause of reduced cell lifespan.
The 4CP (4-(N-carbazolyl)pyridine) developed by the research team is solid and, unlike liquid additives, is nonvolatile, fundamentally preventing these problems. In addition to excellent high-temperature stability, it homogenizes the interfaces between constituent layers to facilitate charge transport. As charge transport becomes smoother, power conversion efficiency also increases.
Perovskite solar cells using 4CP instead of tBP recorded a power conversion efficiency of 26.2% (certified 25.8%), and showed particularly strong performance in long-term operation. While the power conversion efficiency of conventional tBP-based cells dropped to 60% of the initial level within 1,000 hours, 4CP-based cells maintained 80% of the initial efficiency for more than 3,000 hours. In effect, the lifespan more than tripled.
The effect was also clear under high-temperature and extreme conditions. Cells with 4CP maintained 80% of the initial efficiency for more than 400 hours at 85 degrees. In contrast, cells using tBP under the same conditions saw output fall to half or less in 120 hours. They also maintained more than 90% of the initial efficiency even after 200 cycles of a temperature stress test alternating between minus 80 degrees and plus 80 degrees.
The research team said, "This study demonstrates that even if the process is kept the same, simply replacing the additive can effectively solve the biggest weakness of next-generation perovskite solar cells, which is lifespan," adding, "Because it is compatible with existing manufacturing processes, the barrier to mass production is low, which is an advantage of the technology, and we plan to fabricate large-area modules and verify their performance for commercialization."
References
Nature Energy (2025), DOI: https://doi.org/10.1038/s41560-025-01864-z