White-light-emitting diodes using miscible polymer blend doped with phosphorescent dye

✍ Scribed by Hang Ken Lee; Tae-Ho Kim; Jong Hyeok Park; Jai-Kyeong Kim; O Ok Park

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 801 KB
• Volume: 12
• Category: Article
• ISSN: 1566-1199
• DOI: 10.1016/j.orgel.2011.03.001

✦ Synopsis

We demonstrate that voltage-independent and highly efficient white light-emitting diodes (WLED) can be obtained based on phosphorescent dye-doped conjugated polymer blend films. Conjugated polymers are used as the blue and green emitters, as well as the energy host, and a phosphorescent dye is used as the red emitter and guest material. The phaseseparation between the conjugated polymers is suppressed by blending miscible polymer and copolymer having the same moiety. Therefore, we expect that efficient Förster-type energy transfer occurs through this homogeneous morphology. By introducing the copolymer into the emissive layer to enhance its miscibility, we obtained a voltage-invariant white emission from the polymeric LEDs. The luminous efficiency of the WLED with the single active layer is increased dramatically by introducing the phosphorescent dopant as a red emitter.