In order to suppress the viewing angle dependence of top emission organic light emitting diodes (TEOEDs) on a strong microcavity structure, we prepared multi-layered nano scattering film which was consisted with transparent planarizing layer and hazy crosslinked scattering layer. Through such an approach, we could obtain not only a stable color shift and luminance distribution with viewing angle but also a negligible pixel blur level. Meanwhile, we investigated a black tint level of TEOLEDs after attachment of circular polarizer (CP) on various nano scattering films because nano scattering film deteriorates a black level. We found that the black level could be improved from the black tint by reducing the refractive index difference between planarizing layer and scattering layer.

In this work, we applied random wrinkle structure to top emitting organic light emitting diodes (TEOLEDs) inside. Also, by introducing index matching epoxy filler into the encapsulation part, we could dramatically improve the current efficiency with maintaining the suppression effect of viewing angle dependence as well as color shift.

No abstract

We have improved the stability of OLEDs via adjusting the charge balance through partial interface mixing using a linear polymer (LPHTL) which has relatively higher hole mobility than cross-linkable HTL (XHTL). Then we analyzed this phenomenon through hole only device (HOD) and impedance spectroscopy (IS).

In order to obtain the stable viewing angle characteristics of top emission organic light emitting diodes (TEOLEDs) having strong microcavity characteristics, we fabricated nano‐porous film on the glass substrate before depositing highly reflective anode. And then, we could obtain the concave patterned anode by depositing anode on the nano‐porous film and fabricated TEOLED composed of concave patterned layers. From this approach, we could successfully obtain not only the stable color shift and luminance distribution with viewing angle but also high efficiency caused by uneven morphology. In addition, we found that the driving voltage of TEOLED could be reduced due to increased surface area effect of the concave patterned anode, so that the power efficiency was enhanced by about 15% in comparison with reference device.