Domestic researchers have achieved a new record in the photovoltaic performance of 'perovskite/copper indium gallium selenide (CIGS)' tandem solar cells.
The National Research Foundation of Korea (NRF) announced on the 9th that a research team led by Professor Kim Jin-young from Seoul National University's Department of Materials Science and Engineering and Senior Researcher Jeong Jeung-hyeon from the Korea Institute of Science and Technology (KIST) Next-Generation Solar Cell Research Center has developed a technology that can reduce energy loss in perovskite/CIGS tandem solar cells, which are attracting attention as next-generation solar cells, achieving a new photovoltaic performance record of 26.3%.
Perovskite/CIGS thin-film tandem solar cells are solar cells made by stacking two types of thin-film solar cells that absorb different light energies. Due to their lightweight and flexible characteristics, they can be easily attached like stickers to various places such as building facades, windows, the roofs of cars, and sound barriers, making them noteworthy as next-generation solar cells.
The research team devised a method to combine easy-to-manufacture and low-expense perovskite solar cells with CIGS solar cells that absorb a wider range of light, developing a technology that can achieve a high efficiency comparable to silicon-based tandem solar cells in a thin-film form.
First, the Seoul National University research team developed special materials and processes to stably stack perovskite solar cells on top of the rough-surfaced CIGS solar cells. This allowed the two solar cells to adhere perfectly without gaps, achieving optimal performance. The KIST research team optimized the consolidation layer that acts as a bridge between the two solar cells to ensure that energy loss is minimal, enabling the solar cells to perform at 100% capacity.
Through this, they achieved a new photovoltaic performance record of 26.3%, surpassing the previous best record of 24.6% from a German research institute by 1.7%. This record has been included in the latest edition of the official efficiency chart published by the National Renewable Energy Laboratory (NREL) in 2025.
Professor Kim Jin-young noted, 'This NREL chart listing will serve as an opportunity for Korea to secure leadership in perovskite/CIGS thin-film tandem solar cell technology and will become a turning point to accelerate technology development in this field, which has seen somewhat slow growth.'