EGIYON, Develops Tandem Solar Cell with 'World's Highest Efficiency'

The Korea Institute of Energy Research (hereinafter KIER) announced on the 3rd that it has succeeded in producing an ultra-lightweight flexible perovskite/CIGS tandem solar cell, achieving the world's highest efficiency.

The solar cell developed by KIER is lightweight and can be attached to curved surfaces, making it expected to be applied to buildings, automobiles, aircraft, and more in the future.

(From left) Professor Kim Hae-jin of Yonsei University, Dr. Jeong In-young of Korea Institute of Energy Technology Evaluation and Planning, Dr. Kim Ki-hwan of Korea Institute of Energy Technology Evaluation and Planning, Professor Lee Tae-kyung of Gyeongsang National University. Provided by Korea Institute of Energy Technology Evaluation and Planning

Traditionally, silicon-based single-junction solar cells have been mainly used in solar power generation due to their low production cost and advantages in mass production. However, recently, tandem solar cells that combine perovskite solar cells with silicon solar cells to increase efficiency have attracted attention due to the limitations in power generation efficiency of silicon solar cells.

Perovskite is a material with a crystal structure similar to calcium titanate, which has the advantage of effectively absorbing light.

Perovskite/silicon tandem solar cells using this material boast a high efficiency of 34.6%. However, they are heavy and vulnerable to physical shocks, which limits their use in fields where lightweight and applicability are important, such as automobiles, aircraft, and artificial satellites.

To address these issues, recently, flexible thin-film perovskite/CIGS tandem solar cells have been developed.

CIGS is a copper-indium-gallium-selenide (CuIn1-xGaxSe2) compound semiconductor with excellent photoelectric properties, used as the light-absorbing layer in thin-film solar cells. It is especially advantageous for its high flexibility when fabricated on polyimide or metal films.

CIGS-based thin-film solar cells are very lightweight and flexible, allowing their use on curved buildings, automobiles, and aircraft. However, compared to perovskite/silicon tandem solar cells, they have lower efficiency and higher manufacturing complexity, which has prevented them from reaching commercialization.

Accordingly, KIER developed a 'lift-off' process to improve the workability of flexible tandem solar cell manufacturing and enhance the flexibility and lightweight characteristics of the cells.

They also identified the causes of performance improvement in the solar cells. Based on this, the perovskite/CIGS tandem solar cell produced showed a power conversion efficiency of 23.64%, achieving a world-class level.

The lift-off process involves coating a polyimide layer on a glass substrate, fabricating the perovskite/CIGS tandem solar cell on top, and then separating it.

Unlike previous processes that used flexible polyimide film itself as the substrate, this method uses rigid glass as a supporting substrate, enabling more stable cell fabrication than before. Using a flat glass substrate allows uniform deposition of each layer of the solar cell, which improves performance and manufacturing reproducibility, another advantage.

Senior Researcher In-Young Jeong, who led the study, said, "This research is a key achievement proving the commercialization potential of next-generation high-efficiency solar cell technology with flexibility and lightweight characteristics," adding, "It will be an important milestone toward realizing ultra-lightweight flexible solar cells with about 30% efficiency in the future."

Meanwhile, this research was conducted jointly with Professor Tae-Kyung Lee of Gyeongsang National University and Professor Hae-Jin Kim of Yonsei University, supported by the basic project of the Korea Institute of Energy Research.

This content was produced with the assistance of AI translation services.