Recent progress in deep-blue phosphorescent OLEDs

Cyclometallated iridium N-heterocyclic carbene (NHC)-complexes have become known as efficient deep blue triplet emitters in OLEDs. With these emitters suitable CIE color coordinates of CIE x ~ 0.15 and CIE y = 0.1...0.2 can easily be reached. To keep the expensive and tedious synthetic and laboratory screening effort for new emitters and complementary materials as efficient as possible a good computational pre-screening method based on quantum chemical theory is used. In this paper, data will be presented which show a good correlation between calculated and measured values of for example triplet energy, ionization potential and electron affinity. Only by having good control of these parameters it is possible to design efficient and long lasting devices. Based on this, we will show our progress in the deep-blue color region by optimizing the device setup and by employing a new, much more stable complementary material set.