Effect of MgZnO-bilayer/BA-CH3 combination interlayer on emission characteristics of MoO3/F8BT/ZnO hybrid light emitting diodes fabricated on ZnO/Ag/ZnO transparent cathode

The characteristics of MoO3/F8BT/ZnO inorganic/organic hybrid light emitting diodes (IO-HyLEDs) fabricated on ZnO/Ag/ZnO dielectric/metal/dielectric (DMD) and conventional ZnO/ITO were investigated. The DMD had a low sheet resistance of 9 Ω/sq and a high transmittance of 90.7%. The device fabricated on DMD showed similar current density-voltage (J-V) and luminance-current density (L-J) characteristics to that on ZnO/ITO, indicating the possibility of DMD as a promising transparent conductive layer for IO-HyLEDs. The maximum luminous intensity of 237,000 cd/m2 was demonstrated under pulsed condition for the DMD device. We also investigated the effect of the combination interlayer (CIL) at the F8BT/ZnO interface on the IO-HyLEDs. The CIL was composed of a Mg0.52Zn0.48O/Mg0.25Zn0.75O bilayer and a self-assembled dipole molecule (SADM) of BA-CH3. The devices with CIL exhibited an approximately threefold enhancement of the luminous intensity and efficiency in comparison with the devices without CIL. This improvement was considered to be brought about by the enhancement of the electron injection efficiency by CIL.