45 views | Created 2024.12.24 | Modified 2024.12.24 | Public Relations Team

·         Professor Lee Hyun-Ho (Department of Electronic Engineering) and His Research Team Develop Deep-Blue Perovskite Light-Emitting Diodes (LEDs)

- Blue Shift in Emission Wavelength and Improved Stability Through Perovskite Surface Treatment -

- Published a paper in the internationally renowned journal Applied Surface Science, published by Elsevier (IF: 6.3) -

Professor Lee Hyun-Ho (Department of Electronic Engineering) and his research team at Kwangwoon University proposed a dynamic-treatment method using phenylphosphonic dichloride (PPOCl₂) to achieve defect passivation and a blue shift in the emission wavelength of perovskite emissive layers. Their study reported a deep-blue perovskite light-emitting diode (LED) that meets the Rec.2020 video broadcasting standard established by the International Telecommunication Union (ITU).

 (Left) Yoon Beom-Hee, Integrated Master's and Ph.D. Program Researcher; (Right) Lee Hyun-Ho, Professor

Perovskite light-emitting diodes, known as next-generation display devices, are being researched for their high color purity and low processing costs. However, improving the performance of blue perovskite light-emitting diodes is essential for their successful commercialization.

Numerous studies have introduced treatment methods to achieve a blue shift in the emission wavelength of perovskite light-emitting diodes, aiming to meet the deep-blue wavelength (467 nm) specified by Rec.2020, the video broadcasting standard set by the International Telecommunication Union (ITU). However, reports on deep-blue perovskite light-emitting diodes achieving an emission wavelength of 467 nm or lower remain limited. Therefore, understanding the structural mechanisms and achieving a blue shift in the emission wavelength are essential for developing deep-blue perovskites.

This study utilized a dynamic-treatment method with PPOCl₂ to induce defect passivation and a blue shift in the emission wavelength of perovskite emissive layers. As a result, the phosphonate group (P=O) in PPOCl₂ formed P-O-Pb bonds with Pb² defects in the perovskite, effectively passivating the defects and improving the device's performance and operational stability. Simultaneously, the HCl byproduct filled halide vacancies within the perovskite, increasing the Cl content, which led to a blue shift in the emission wavelength. The resulting perovskite light-emitting diode exhibited a deep-blue emission wavelength of 467 nm, meeting the requirements of the Rec.2020 standard.

The research team hopes that the spectral shift mechanism achieved through the dynamic-treatment method using PPOCl₂ will be applied not only to perovskite light-emitting diodes but also to various other fields involving blue light-emitting diodes.

Meanwhile, this research was conducted with support from the University Research Institute Program (2018R1A6A1A03025242, 2022R1F1A1066526) and Kwangwoon University. The findings were published in Applied Surface Science (IF: 6.3), an internationally renowned journal by Elsevier.

https://doi.org/10.1016/j.apsusc.2024.161623