UNIST Research Team Develops World's Most Efficient Solar Cell Manufacturing Technology

[Asia Economy Yeongnam Reporting Headquarters, Reporter Hwang Du-yeol] A team led by Distinguished Professor Seok Sang-il of the Department of Energy Chemical Engineering at UNIST has developed a technology for manufacturing high-efficiency perovskite solar cells.

Perovskite solar cells are manufactured by coating a thin film of crystalline semiconductor with a perovskite structure. Therefore, controlling the crystallization behavior of the thin film to minimize internal defects is crucial for achieving high efficiency.

The UNIST research team discovered a “new method and principle for controlling the crystallinity of the perovskite photoactive layer semiconductor” and applied it to the manufacturing of perovskite solar cells.

Solar cells manufactured using this principle achieved a world-leading efficiency of 26.08%, which was also certified as the world’s highest efficiency (25.73%) by the U.S. National Renewable Energy Laboratory (NREL).

This achievement was published as an Accelerated Article Preview (AAP) on February 16 in the world’s most prestigious journal, Nature (Impact Factor: 69.504).

For high efficiency in perovskite solar cells, it is very important to control defects inside the perovskite thin film at an extremely low level.

These defects also significantly affect the long-term stability of solar cells. Controlling the thin film formation process and understanding the principles behind it are key technological elements that satisfy both high efficiency and long-term stability simultaneously.

Image of crystallization behavior of controlled perovskite thin films depending on the type of added alkylammonium chloride.

Professor Seok Sang-il said, “We used alkylammonium chloride, which undergoes dequantization during the crystallization stage while bonding with the perovskite components, and this optimal combination is the core of this research result.”

He added, “By combining with alkyl groups, we were able to optimally control the evaporation rate of the solvent during the coating and heat treatment processes of the perovskite precursor solution. This combination enabled the manufacture of perovskite thin films with extremely flat surfaces and minimal internal defects, resulting in excellent crystallinity.”

Co-corresponding author Professor Shin Tae-ju of the UNIST Graduate School of Semiconductor Materials and Components said, “This research is very meaningful as it revealed and organized the principles of the crystallization process of halide anion-containing perovskites by real-time observation using the UNIST-PAL beamline at the Pohang Accelerator Laboratory. We expect that this can be extended to the manufacture of perovskite thin films with high crystallinity and various compositions in the future.”

Professor Seok emphasized, “With this research, perovskite solar cells with efficiencies exceeding 26% will soon surpass the efficiency of silicon solar cells. This is the starting point of the journey to achieve efficiencies above 27%.”

This research involved UNIST researchers Park Jae-wang and Kim Jong-beom as first authors. The research was supported by the Korea Research Foundation’s Leader Researcher Support Program.

Perovskite solar cells are next-generation solar cells that are thin, lightweight, flexible, and can be cheaply produced by solution processing. Perovskite is used as the photoactive layer material that generates charge carriers (electrons and holes).

Professor Seok Sang-il was the first to surpass 20% efficiency in perovskite solar cells and holds the world’s highest certified efficiency record.

He also was the first in the world to present the perovskite heterojunction n-i-p solar cell structure, and currently, all high-efficiency perovskite solar cells with efficiencies above 25% use this structure.

He has also demonstrated academic excellence by publishing 10 papers in the world’s most prestigious journals, Nature and Science, including this one.

In 2022, he was selected as a co-recipient of the Rank Prize in Optoelectronics, a science award given by the UK Rank Foundation, in recognition of his contributions to the birth and development of perovskite solar cells.

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