EL Properties and Mechanism of Organic Light-Emitting-Diode Prepared by squarylium and dicyanomethylene Dye Dopping

초록

To obtain highly pure red emission, we prepared organic light-emitting-diodes(OLEDs) with a fluorescent dye-doped emission layer by vapor deposition method. the OLED has a double-layer structure. The hole transfer layer is a triphenyl diamine(TED) The emission layer consists of an Alq3 doped with squarylium(Sq) and dicyanomethylene (DCM) dye. We discussed the electroluminescence(EL) and electrical properties with doping concentration. The EL spectra of the specmens with two dyes doped emission layers do not include the spectra of DCM (620nm) and Alq3 (520nm) and only the EL from Sq (670nm) can be observed at Sq(10mol%)-doped Alq3 LED. The EL effciency and luminance of DCM-doped specimen is 2∼3 times higher than those of undoped specimen. Because DCM molecules are thought to be acted as energy transfer site in Alq3 molecules The energy transfer process from Alq3 to Sq through DCM is thought to exist in the Sq and DCM doped Alq3 LED