Professor Jung-Yong Lee and his research team (Dr. Min-Ho Lee and Mr. Min Seok Kim) from our school has successfully developed a 27%-class high-efficiency perovskite solar cell capable of withstanding high-temperature and high-humidity environments without encapsulation.
This breakthrough simultaneously addresses both efficiency and stability, which have long been considered the core challenges in commercializing next-generation, high-efficiency thin-film solar cells.
The achievement is expected to expand the potential of perovskite solar cells into various future energy platforms, such as Building-Integrated Photovoltaics (BIPV), portable power sources, and aerospace power applications.
Professor Lee’s research team collaborated with Professor Sang-min Lee’s team from the Department of Physics and Professor Sang Kyu Kwak’s team from Korea University.
By designing the energy levels of organic polymers, the joint team successfully controlled the electronic structure and charge transport pathways of perovskite/organic hybrid solar cells, realizing high efficiency and high stability without any encapsulation.
This study was supported by the Nano-Material Technology Development Program, the Key Research Program, and the Supercomputing Application Sophistication Project funded by the Ministry of Science and ICT and the National Research Foundation of Korea. The findings were published on May 18, 2026, in the prestigious international energy journal Nature Energy (IF: 60.1).
While perovskite solar cells are considered promising candidates for next-generation photovoltaics due to their high power conversion efficiency and lightweight nature, they are highly vulnerable to moisture and heat. This susceptibility makes long-term stable operation difficult, historically limiting their practical use without encapsulation materials to address these vulnerabilities.
The research team focused on the issue that when organic polymers are used in conventional hybrid structures, inefficient charge transfer leads to hole accumulation, causing an “S-shaped current-voltage (J-V) distortion” under actual device operating voltages. Through 3D multiphysics simulation and ultrafast spectroscopic analysis, they identified this phenomenon as the root cause of performance degradation and introduced a “PM1” organic polymer with a deep energy level to resolve it.
PM1 aligns the energy flow so that charges transfer in a stepwise manner rather than accumulating at specific interfaces, thereby eliminating the S-shaped distortion. Consequently, the device achieved a peak efficiency of 27.18% and a world-class certified efficiency of 26.71%.
The PM1-based layer facilitates near-infrared absorption and charge transport while simultaneously acting as a protective layer that blocks external moisture penetration. As a result, even without encapsulation, the cell maintained over 95% of its initial efficiency after 3,000 hours under harsh conditions of 85°C and 85% relative humidity (RH).
Predictions using the Arrhenius model showed that the T80 (the time required to drop to 80% of initial efficiency) at room temperature (25°C) translates to 35,590 hours. This indicates that a long-term operational stability of approximately four years can be secured even without encapsulation.
Professor Jung-Yong Lee, the principal investigator, stated, “This achievement overcomes the trade-off between the efficiency and stability of perovskite solar cells through a novel electronic structure design, marking a significant milestone for the commercialization of next-generation solar cells.”
Dr. Min-Ho Lee, the first author, added, “We identified the root cause that limits efficiency in conventional solar cell structures from the perspective of charge flow during actual operation, and resolved it through electronic structure engineering.”
