Enhancement of the Magnetic Field Effect on the Emission Intensity of an Organic Light-Emitting Diode Induced by the Operating Time

概要

論文の詳細を見る
The magnetic field effect (MFE) on the emission intensity was investigated for an organic light-emitting diode (OLED) with a poly(1,4-phenylenevinylene) (PPV) derivative as a luminescent layer, and the dependence of the emission intensity on the total operating time was investigated. By applying an external magnetic field, the emission intensity increased, and its magnitude increased from ${<}10$ to ${>}50$% at 5 V with increasing operating time. The emission intensity also increased with time, and reached its maximum in 20 h, but the MFE continued to increase over 100 h. The increases in the MFE and the emission intensity were considered to originate from the promotion of long-range charge recombination between electrons and holes, which were induced by the structural change of the OLED material. Heating the OLED to temperatures of 80 °C and lower produced, however, no change in the magnitude of the MFE, irrespective of the significant decrease in emission intensity. Therefore, global heating to low temperatures was found not to induce such effects.
2009-06-25