EXD-LnOLED · Advancing Exciton Dynamics in In-situ/Operando Spectroscopic Study of Lanthanide-based OLEDs

This research project, ""EXD-LnOLED,"" aims to enhance the efficiency and functionality of lanthanide-based organic light-emitting diodes (Ln-OLEDs). OLEDs are efficient electroluminescent (EL) light sources for panel displays, light communication, and laser diode applications. To maximize efficiency, it is crucial to fully utilize excitons, which consist of 25% singlet and 75% triplet exciton states. Lanthanide complexes are ideal for OLEDs due to their unique optical properties, such as high photoluminescence quantum yield (PLQY), color tunability, and narrow linewidths. This triplet sensitization allows for potentially 100% utilization of exciton energy, leading to cost-effective EL devices. However, despite their high PLQY of around 80%, the external quantum efficiency (EQE) in operational OLEDs is limited to about 10%, restricting practical applications. The primary objective of this project is to develop in-situ/operando spectroscopic techniques to study exciton dynamics and energy transfer within operating Ln-OLEDs. By using advanced methods such as ultrafast transient absorption spectroscopy and time-resolved electroluminescence under in-situ/operando conditions, the research will uncover the mechanisms limiting current Ln-OLED efficiency. Additionally, the project will create innovative methods for detecting changes from electron injection, enhancing understanding of charge balance and dynamics in Ln-OLEDs. Ultimately, the project seeks to address efficiency challenges and achieve state-of-the-art Ln-OLEDs with the highest EQE. These insights will inform the design of high-efficiency devices, aiming for 100% exciton energy utilization, thus advancing energy-saving technologies and next-generation lighting solutions.""