"Over 31% Efficiency Achieved in Ambient Air"... UNIST Lowers the Barrier for Mass Production of "Dream Solar Cells" [Reading Science]

Achieving World’s Highest Efficiency for Perovskite-Silicon Tandem Solar Cells Made in Ambient Air
Three-Component Interfacial Coating Technology Overcomes Moisture Vulnerability
Published in Nature Photonics

A key technology that will lower the barrier to mass production of perovskite-silicon tandem solar cells, regarded as a 'game changer' for the next-generation solar market, has been developed by a Korean research team. The technology has been recognized for significantly boosting commercialization prospects, as it achieves world-class efficiency even under standard atmospheric conditions, without the need for specialized production facilities that block moisture and oxygen.

On June 11, UNIST (Ulsan National Institute of Science and Technology) announced that the research team led by Distinguished Professor Sangil Seok and Professor Kyungjin Choi, in collaboration with researchers from King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, has developed a ternary interfacial coating material for high-efficiency tandem solar cells.

Perovskite thin films applied with TSN interlayers exhibited much more uniform photoluminescence intensity compared to conventional self-assembled monolayers (SAMs). This indicates that the thin films were more evenly formed and defects causing charge loss were reduced, demonstrating advantages for the fabrication of high-efficiency and high-quality solar cells. Provided by the research team

The research results were published in Nature Photonics, a leading global journal in optics and photonics.

Perovskite-silicon tandem solar cells are a next-generation technology that stacks two types of solar cells vertically to use sunlight more efficiently. The upper perovskite cell absorbs short-wavelength light, while the lower silicon cell absorbs the remaining light, allowing for efficiency beyond the limits of conventional silicon solar cells. For this reason, major countries around the world are competing to secure leadership in these so-called 'dream solar cells.'

However, perovskite is vulnerable to moisture and oxygen, which has meant that high-efficiency cells had to be produced in specialized environments. This has been cited as a factor raising the cost of large-area production and hindering commercialization.

Surpassing 31% without special facilities... The biggest commercialization barrier overcome

The research team solved this problem by developing a ternary coating material that adds GDMA and AG to the conventional interfacial material (Me-4PACz). GDMA helps the coating layer form uniformly on the electrode surface, while AG reduces interfacial defects to increase charge transport efficiency.

Using this method, the tandem solar cell achieved a power conversion efficiency of 31.72%, despite being fabricated in a standard atmospheric environment. This is the highest efficiency among perovskite-silicon tandem cells produced under ambient conditions worldwide. The certified efficiency was also confirmed at 31.36%.

Durability was also greatly improved. Even after exposure to 85 degrees Celsius for 600 hours without any protective packaging, more than 92% of the initial performance was maintained. After exposure to strong simulated sunlight for 1,000 continuous hours, more than 90% efficiency was retained.

Research team photo. (From left) Professor Sangil Suk, Professor Kyungjin Choi, Dr. Kisu Kim, Researcher Youngim Noh. Provided by UNIST

The research team also confirmed that this technology is advantageous for large-area production. Uniform perovskite thin films were formed on large-area substrates sized 7×7 cm², and the defect rate was also reduced.

Professor Kyungjin Choi of UNIST said, "This research aligns with the government's K-Moonshot Project, which aims to develop ultra-high-efficiency multi-junction solar cells with a significant technological lead," and added, "We expect this will make a major contribution to the commercialization of next-generation solar technologies."

Distinguished Professor Sangil Seok of UNIST stated, "For the commercialization of high-efficiency tandem solar cells, we must address not only performance but also reproducibility and production cost issues in actual processes. This research demonstrates that uniform interfacial thin films and high reproducibility can be achieved even in standard atmospheric environments."

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