Electroluminescence degradation study of tris-(8-hydroxyquinoline)aluminum-based organic light emitting diode and influence of light

Organic light emitting diodes (OLEDs) based on tris-(8-hydroxyquinoline)aluminum (Alq₃), the most widely used electroluminescent material in organic electroluminescent devices, have been fabricated. The electroluminescence degradation of Alq₃-based OLED during the light exposure under the normal ambient has been studied. It is found that, during the light exposure of OLEDs in the normal ambient, luminescent quencher is formed in Alq₃ thin film in the OLEDs and this is acting as non-emissive electron-hole recombination center. Hence, during the operation of OLEDs exposed to light in the normal ambient, the recombination of charge carriers takes place in the Alq₃ and also in the nearby non-emissive electron-hole recombination center in the Alq₃ thin film in the OLED, quenching the electroluminescence from that of as-prepared OLEDs.