New high efficiency white-top emitting OLED formed at TU Dresden

Researchers at TU Dresden have developed a new highly efficient white top-emitting OLED design that has outstanding color quality as its top feature.

It is also compatible with flexible OLEDs.

A refractive index matched microlens film was laminated to the OLED so that direct optical contact could be formed. This resulted in the achievement of an emission from 410 to 750 nm, CIE coordinates of (0.472, 0.430) and CRI of 93. The efficiency has been measured up to 30 lm/W and is at par with the newest record white OLEDs from OSRAM and Novaled.

This lamination allows the use as an encapsulation film when oxygen and water barriers are added.

As per the researchers, top-emitting OLEDs are better for lighting applications because they can be processed on cheap metal substrates in roll-to-roll processes. However, an optical microresonator is formed between the highly reflective bottom metal electrodes and the semitransparent top and the emission is spectrally narrow and has a noticeable angular dependence.