A STUDY OF THE ELECTROLUMINESCENCE PROCESS OF AN ORGANIC ELECTROLUMINESCENCE DIODE WITH AN ALQ3 EMISSION LAYER USING A DYE-DOPING METHOD

The authors prepared an organic electroluminescent diode (organic LED) With hole transport material and aluminium quinoiline and another organic LED with an additional electron blocking layer using the DCM partial doping method. The authors studied the change in the EL spectra accompanied by the applied current in the specimens by means of the peak separation method. The electron-hole recombination did not always occur at the emission layer near the interface between the hole transport layer and the Alq3 emission layer from the initial EL stage after electrons had been transported from cathode to the interface. It was proved that the emitting region is shifted from the cathode side to the anode side in the emission layer with increasing applied current, especially by electron injection from the cathode. In addition, from the measurement of the specimen with an electron blocking layer, the authors found that the dominant EL process is not due to the carrier trap model in an organic DCM-doped Alq3 LED.