| 초록 |
Low efficiency of polymer light emitting diodes (PLEDs) based on dialkoxy substituted PPV is usually caused by unbalanced injection of holes and electrons from the electrodes. The design of the polymer structure was aimed at the enhancement of the EL efficiency, e.g. hole injection efficiency, of the device without affecting the intrinsic properties of alkoxy substituents. We attempted to improve the EL efficiency by introducing oxadiazole units in the side chain, which has an electron transporting and hole blocking properties. Also the polymer has flexible spacer between backbone and conjugated 1,3,4-oxadiazole. The polymers exhibit significantly higher EL efficiency (600 cd/m2 at 3.02 mA/m2) than that of MEH-PPV. The HOMO and LUMO energy levels were obtained by cyclic voltammetry. Electroluminescence and current-voltage-luminescence characteristics were investigated as well. |
