Research Team of Professors Yang Sang-mo from the Department of Physics and Ok Kang-min from the Department of Chemistry Publishes Article in Prestigious International Journal Advanced Materials
The research team led by Professor Yang Sang-mo from the Department of Physics and Professor Ok Kang-min from the Department of Chemistry has identified the temperature-dependent evolution of ferroelectric domains and the mechanism of the ferroelectric-to-paraelectric phase transition in a two-dimensional halide perovskite ferroelectric material using nanoscale imaging techniques.
The study was conducted jointly with Professor Yang Sang-mo from the Department of Physics as the corresponding author, master’s student Jung Tae-hyun as the first author, and the research team of Professor Ok Kang-min from the Department of Chemistry as the co-corresponding author. This study was supported by the Basic Research Laboratory (BRL) program, the Mid-Career Researcher Program, and the Global Leader Research Program from the National Research Foundation of Korea, and its findings were recently published online in Advanced Materials (IF = 26.8), a prestigious international journal in the field of materials science.
Halide perovskites are attracting attention as high-efficiency, low-cost next-generation solar cell materials, and compared to their three-dimensional counterparts, two-dimensional halide perovskites are known for their excellent stability. In addition to superb optical properties, they also offer functional properties, such as ferroelectricity, leading to active research for their application in various electronic devices. However, producing ferroelectric devices requires an understanding of temperature-dependent ferroelectric behavior, and conventional studies have been limited to macroscopic properties like the ferroelectric phase transition temperature, or Curie temperature.
The research team directly observed the temperature-dependent changes in ferroelectric domains at the nanoscale using piezoresponse force microscopy (PFM) and proved the mechanism of the ferroelectric-to-paraelectric phase transition based on these observations. Notably, the team confirmed that local ferroelectric-to-paraelectric transitions begin at temperatures lower than the Curie temperature, and as the temperature increased, large domains split into smaller ones and localized paraelectric regions emerged. Additionally, analysis based on the Landau-Ginzburg-Devonshire theory confirmed that this phase transition is of second order. This second-order was cross-verified using various techniques, including powder X-ray diffraction experiments that showed gradual structural changes with different temperature.
Commenting on the research, Professor Yang Sang-mo stated, “By directly observing the temperature-dependent changes in ferroelectric domains at the nanoscale, this study offers a microscopic understanding of the ferroelectric-to-paraelectric phase transition, providing an essential basis for the application of two-dimensional halide perovskites in ferroelectric devices.”
Professor Ok Kang-min added, “This study elucidates nanoscale structural changes in two-dimensional halide perovskites at different temperatures, offering fundamental data to ensure the reliability of future ferroelectric and optoelectronic devices.”
▶Paper title: “Spatially Resolved Observation of Ferroelectric-to-Paraelectric Phase Transition in a Two-Dimensional Halide Perovskite”
▶Paper link: https://advanced.onlinelibrary.wiley.com/doi/10.1002/adma.202506270
The study was conducted jointly with Professor Yang Sang-mo from the Department of Physics as the corresponding author, master’s student Jung Tae-hyun as the first author, and the research team of Professor Ok Kang-min from the Department of Chemistry as the co-corresponding author. This study was supported by the Basic Research Laboratory (BRL) program, the Mid-Career Researcher Program, and the Global Leader Research Program from the National Research Foundation of Korea, and its findings were recently published online in Advanced Materials (IF = 26.8), a prestigious international journal in the field of materials science.
Halide perovskites are attracting attention as high-efficiency, low-cost next-generation solar cell materials, and compared to their three-dimensional counterparts, two-dimensional halide perovskites are known for their excellent stability. In addition to superb optical properties, they also offer functional properties, such as ferroelectricity, leading to active research for their application in various electronic devices. However, producing ferroelectric devices requires an understanding of temperature-dependent ferroelectric behavior, and conventional studies have been limited to macroscopic properties like the ferroelectric phase transition temperature, or Curie temperature.
The research team directly observed the temperature-dependent changes in ferroelectric domains at the nanoscale using piezoresponse force microscopy (PFM) and proved the mechanism of the ferroelectric-to-paraelectric phase transition based on these observations. Notably, the team confirmed that local ferroelectric-to-paraelectric transitions begin at temperatures lower than the Curie temperature, and as the temperature increased, large domains split into smaller ones and localized paraelectric regions emerged. Additionally, analysis based on the Landau-Ginzburg-Devonshire theory confirmed that this phase transition is of second order. This second-order was cross-verified using various techniques, including powder X-ray diffraction experiments that showed gradual structural changes with different temperature.
Commenting on the research, Professor Yang Sang-mo stated, “By directly observing the temperature-dependent changes in ferroelectric domains at the nanoscale, this study offers a microscopic understanding of the ferroelectric-to-paraelectric phase transition, providing an essential basis for the application of two-dimensional halide perovskites in ferroelectric devices.”
Professor Ok Kang-min added, “This study elucidates nanoscale structural changes in two-dimensional halide perovskites at different temperatures, offering fundamental data to ensure the reliability of future ferroelectric and optoelectronic devices.”
▶Paper title: “Spatially Resolved Observation of Ferroelectric-to-Paraelectric Phase Transition in a Two-Dimensional Halide Perovskite”
▶Paper link: https://advanced.onlinelibrary.wiley.com/doi/10.1002/adma.202506270