Seoul National University College of Engineering announced that a research team led by Prof. Yongtaek Hong from the Department of Electrical and Computer Engineering has developed a high-performance transparent organic light-emitting diode (OLED) incorporating highly conductive transparent metal mesh top electrodes fabricated using a selective metal deposition technique. The research was published in the journal Materials Horizons and was selected as the outside front cover image for the issue.
Transparent OLEDs have attracted significant attention for next-generation applications, including advanced displays, augmented reality (AR), automotive displays and smart windows, because of their capability for bidirectional light emission. However, despite achieving high optical transparency and excellent electrical performance, conventional transparent electrodes often face limitations when directly integrated into OLED devices because their fabrication processes can chemically or physically damage the underlying organic layers.
To address this challenge, the research team developed a metal-patterning technology based on a high-resolution transfer-printing process using a metal-vapor-desorption layer (MVDL). This approach enables the fabrication of highly conductive transparent metal mesh patterns with micrometer-scale resolution without requiring chemical washing or lift-off processes. As a result, high-quality vapor-deposited metal patterns can be directly formed on organic stacks while minimizing damage to the underlying organic device layers.
The fabricated metal mesh electrodes simultaneously achieved high optical transparency of 93%–99% and low sheet resistance of 1.1–4.0 Ω/sq. In addition, the electrodes exhibited a figure of merit (defined as the ratio of electrical conductivity to optical conductivity) exceeding 10,000, representing one of the highest figures of merit reported for sub-micrometer-thick transparent electrodes.
Demonstrating device performance
The research team further demonstrated transparent OLEDs incorporating the metal mesh electrodes as top electrodes. The resulting devices exhibited excellent transparency and electroluminescent performance without degradation of the underlying organic layers, highlighting the potential of this technology for next-generation transparent display applications.
According to the research team, the proposed technology offers both process simplicity and scalability by enabling direct high-resolution patterning of metal electrodes through conventional vacuum thermal evaporation.
Hong highlighted the significance of the research, stating, “This study presents a new process strategy that simultaneously achieves the excellent electrical characteristics and transparency of high-performance metal electrodes while allowing direct micropattern formation on organic devices. We expect this technology to serve as a key electrode platform for transparent displays and flexible optoelectronic devices, as well as a core manufacturing technology for transparent top electrodes in emerging applications such as facial recognition panels.” https://techxplore.com/news/2026-06-transparent-oled-advance-ar-displays.html
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