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 degrees C and glass transition temperatures at 75-137 degrees 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/m(2) at a current density of 2900 A/m(2) with high white color quality (Commission Internationale de l'Eclairage (CIE) coordinates of (0.33, 0.34)). (C) 2007 Wiley Periodicals, Inc.