Highly efficient tris(8-hydroxyquinoline) aluminum-based organic light-emitting diodes utilized by balanced energy transfer with cosensitizing fluorescent dyes

Abstract

We report on the development of highly efficient organic light-emitting diodes (OLEDs) utilized by balancing the energy transfer between multiple dopants, that is, multiple emissions from the multiple dopants were realized by balanced distributed energy transfer. From the cosensitizing fluorescent OLEDs, the peak external quantum efficiency (EQE) of 4.8% at 130 cd/m(2) is demonstrated, which realized theoretical limits of similar to 5.0% and means that nearly 100% of the singlet excitons are radiative. Also, the optimized device accompanying thickness-modulated electron transport layer for the enhanced light outcoupling demonstrated the highly improved peak EQE and current efficiency of 6.7%, and 23.4 cd/A. (C) 2009 American Institute of Physics. [doi:10.1063/1.3243689]