Temperature dependence of the electroluminescence for tris(8-hydroxy) quinoline aluminum (Alq/sub 3/) light emitting diode

Summary form only given.Functional organic materials have gained increasing attention in recent years due to their promise in the fabrication of full color emitting displays. Electroluminescent devices based on thin films of evaporated organic molecules, conjugated polymers have been extensively investigated because of their red-green-blue output color, light weight, mechanical flexibility and ease of fabrication. In this report, it has been observed that up to a certain temperature luminance intensity decreases with decreasing temperature and then saturates in the low temperature region. The quantum efficiency increases with decreasing temperature and finally reaches to a constant value. From the voltage dependent study we have observed that there is an optimum voltage required to get the maximum efficiency We have investigated the luminance intensity of the organic light emitting diode with tris (8-hydroxy) quinoline aluminum (Alq/sub 3/) as the electron transport layer as well as the emissive layer and N,N´-diphenyl N,N´ bis (3-methylphenyl)-[l-l´-biphenyl] 4-4´-diamine (TPD) as the conventional hole transport layer, over the temperature range from 10K to 300K. We have also investigated the external quantum efficiency with the bias voltage up to 12V.