TADF material development for high-efficiency deep-blue hyper-fluorescent OLEDs (Conference Presentation)

Abstract

The low efficiency of fluorescent blue OLED pixels remains one of the top issues for OLED panel makers despite the success that OLED displays have had on the market in the last decade. Recent progress on the TADF technology, however, has shown this technology´s potential to finally deliver high-efficiency deep-blue materials that also have enough stability for OLED panels. CYNORA has already shown that the customer specifications for color and efficiency can be reached and the lifetime is in the final development stage. We were able to reach these results with two separate TADF approaches, the self-emitting and the co-emitting (or hyper) approach. In this paper, we will show some of the requirements for the TADF emitter that are necessary to achieve good results in the co-emitting approach. We will discuss the theoretical requirements to achieve good energy transfer from a TADF emitter to a fluorescent emitter. We will also show device results that confirm the required deep-blue color of the TADF emitter for efficient hyper-fluorescent devices. And we will also give an update on our latest results where we have achieved more than 20% EQE (external quantum efficiency) at deep-blue colors with a CIEy 1931 coordinate of ≤0.15.