An emission layer with the poly-vinylcarbazole (PVK) and Ir(ppy) 3[tris(2-phenylpyridine)iridium(III)] as the host and guest materials, respectively, was prepared on a PEDOT:PSS/ITO substrate. TPBI [2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)] was introduced to improve the light efficiency of the devices. Green phosphorescence polymer LEDs with the structure ITO/PEDOT:PSS/PVK:Ir(ppy)3/TPBI/LiF/ Al were fabricated and their electrical and optical properties investigated at various doping concentrations (0.5wt%to2.5wt%) of Ir(ppy)3. The maximum luminance and current density were about 8600cd/m2 and 155mA/cm2 at 7V, respectively, when the TPBI layer was introduced between the emission layer and cathode electrode film. The emission spectrum and Commission International d'Eclairage (CIE) color coordinates were about 512nm and (x,y=0.27 to 0.28, 0.61 to 0.63), respectively, showing a green color.
Bibliographical noteFunding Information:
This work was supported by a Korea Research Foundation Grant funded by the Korean Government (KRF-2008-521-D00261)
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics