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Fishing‑net molecular network blocks moisture, achieves over 26% photovoltaic conversion efficiency even after repeated immersion
A next-generation solar cell technology that maintains its performance even in rain or when submerged in water has been developed. By solving the moisture stability issue, regarded as the biggest weakness of perovskite solar cells that are attracting attention as next-generation solar cells, the researchers have increased the potential for commercialization.
 
The National Research Foundation of Korea (NRF) announced on the 21st that a research team led by principal researchers Kim So-yeon and Lim Dong-chan at the Korea Institute of Materials Science (KIMS) has developed a technology that forms a fishing-net-like molecular network at the perovskite interface to block moisture penetration.
 
This research outcome was carried out with support from the Future-Pioneering Convergence Technology Program promoted by the Ministry of Science and ICT and the NRF, as well as from the basic program of the Korea Institute of Materials Science. It was published on July 17 in Nano-Micro Letters, a top-tier international journal in the fields of nanoscience, nanotechnology, and materials science.
 
Perovskite solar cells can achieve efficiencies comparable to conventional silicon solar cells while having lower fabrication costs. However, perovskite materials are extremely vulnerable to moisture and oxygen, giving them a critical weakness in that their performance drops sharply when exposed to rain or humidity.
 
Up to now, approaches have mainly focused on blocking external water with thick protective layers, but this increases manufacturing costs and reduces flexibility.
 
The research team proposed a new approach of making the material itself resistant to water instead of blocking the exterior. Using metal ions (Cu2+) as linkers, they combined a “rigid organic molecule (BCP)” and a “flexible polymer (PEIE)” to form a dense, fishing-net-like molecular network at the perovskite interface. BCP acts as a barrier that prevents moisture from penetrating, while PEIE gently connects the rigid BCP segments, acting as both an adhesive and a buffer.
 
The structure developed by the research team not only prevents moisture from penetrating inside, but also effectively suppresses ion migration, which is a major cause of performance degradation in solar cells.
 
In particular, the team verified the water resistance of the solar cells through immersion tests in which the devices were repeatedly dipped in actual water. They achieved a photovoltaic conversion efficiency of over 26% using solar cells fabricated in ambient air without a separate glovebox. Even after repeated immersion tests, the devices demonstrated excellent water resistance, with their performance recovering.
 
Principal researchers Kim So-yeon and Lim Dong-chan said, “The biggest distinction of this study is that we made the solar cell material itself highly resistant to water,” adding, “We plan to apply this technology to mass-production processes and tandem solar cells combined with silicon solar cells, and to promote early commercialization in various fields such as building-integrated photovoltaics and agrivoltaics.”
 
 
 

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