Relationship between exciton recombination zone and applied voltage in organic light-emitting diodes

In this paper, the relationship between exciton recombination zone and applied voltage in organic light-emitting diodes (OLEDs) ITO/NPB (40 nm)/Alq3(w nm)/rubrene(3 nm)/Alq3(50−w)/Al, in which a 3 nm rubrene as sensing layer is inserted in Alq3 layer at different depth, is studied. By comparing the electroluminescence (EL) spectra of device driven under different applied voltages, a conclusion can be drawn that the recombination zone shifts logarithmically with increasing applied voltages.