White top-emitting organic light-emitting diode based on resonant-enhanced blue emission

Microcavity effect usually exists in the top-emitting organic light-emitting diode(TEOLED) due to the high reflectance of both the cathode and the anode. The suppression to the blue emission induced by the microcavity effect results in the difficulty in realizing a white light emission in TEOLEDs. The classical optics theory is used to design the cavity length and strengthen the blue emission. Based on the first order resonance on the blue band, white light composed of blue and red emission is realized. Further, different interlayers are inserted into the emission layers to study the formation and the recombination zone of the excitions. It is found that it has facilitated suppressing the shifting of the recombination zone with the voltage by inserting the electron block layer into the hole-dominated device. The stability of top-emitting white light is improved.