Pure white‐light‐emitting diodes from phosphorescent single polymer systems

New white polymeric light-emitting diodes from phosphorescent single polymer systems have been developed using a blue-light-emitting fluorene monomer copolymerized with a red-light-emitting phosphorescent dye, and end-capped with a green-light-emission dye. All of the copolymers have good thermal stability with 5% weight loss temperatures at 380–413 °C and glass transition temperatures at 75–137 °C. We obtained white-light-emission devices by adjusting the molar ratio of the comonomers with a structure of indium tin oxide/poly(3,4-ethylenedioxythiophene): poly(styrene sulfonic acid)/polyvinylcarbazole (PVK)/emission layer/Ca/Ag. The highest brightness in such a device configuration is 300 cd/m2 at a current density of 2900 A/m2 with high white color quality (Commission Internationale de l'Eclairage (CIE) coordinates of (0.33, 0.34)). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 464–472, 2008