Effect of Reduced Singlet-Triplet Annihilation Through Triplet Exciton Control on Blue Fluorescent Organic Light-Emitting Diodes

Abstract

In this work, efficient blue fluorescent organic light-emitting diodes (FOLEDs) could be demonstrated by using triplet exciton control (TEC) which means reduced singlet-triplet annihilation (STA) in emitting layer (EML). TEC material, which can be reduced to triplet exciton of dopant in EML consists of host, dopant, and TEC, can perform the important roll to reduce the STA among the exciton quenching process such as singlet-singlet and triplet-triplet annihilation. Therefore, TEC material energy level from the device structure point of view should be both lower triplet state and higher singlet state than dopant in EML. Blue FOLEDs using TEC as well as host-dopant system indicate the improved whole device properties such as luminous efficiency, external quantum efficiency, and roll-off ratio compared with that of general blue FOLED without TEC.