Development Of A Highly Efficient, Strongly Coupled Organic Light-Emitting Diode Based On Intracavity Pumping Architecture

We report a highly efficient polariton organic light-emitting diode (POLED) based on an intracavity pumping architecture, where an absorbing J-aggregate dye film is used to generate polariton modes and a red fluorescent OLED is used for radiative pumping of emission from the lower polariton (LP) branch. To realize the device with large-area uniformity and adjustable coupling strength, we develop a spin-coating method to achieve high-quality J-aggregate thin films with controlled thickness and absorption. From systematic studies of the devices with different J-aggregate film thicknesses and OLED injection layers, we show that the J-aggregate film and the pump OLED play separate roles in determining the coupling strength and electroluminescence efficiency, and can be simultaneously optimized under a cavity design with a good LP-OLED emission overlap for effective radiative pumping. By increasing the absorption with thick J-aggregate film and improving the electron injection of pump OLED with Li2CO3 interlayer, we demonstrate the POLED with a large Rabi splitting energy of 192 meV and a maximum external quantum efficiency of 1.2%, a record efficiency of POLEDs reported so far. This POLED architecture can be generally applied for exploration of various organic materials to realize novel polariton devices and electrically pumped lasers. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement