Low Temperature Magnetic Field Effects In Alq_3-based Organic Light Emitting Diodes

摘要

The magnetic field effects on injection current and electroluminescence have been investigated for aluminum tris(8-hydroxyquinoline) (Alq_3)-based organic light emitting diodes at the temperature of 12 K. The experimental traces of electroluminescence exhibit a rapid rising at low magnetic field, followed by a decrease at high field strength, whereas the injection current increases continuously. The drive dependence of the high field effect of the quantum efficiency matches that which is expected for the triplet-triplet annihilation process, indicating that the delayed fluorescence from the triplets' annihilation significantly contributes to the field dependent light emission in our devices.