BASF has developed phosphorescent emitters based on iridium carbene complexes aiming to combine high efficiencies with high diode lifetime. However, since the device performance is a result of a complex interplay between electrical and optical properties of emitter and host molecules, understanding of charge and exciton dynamics on a molecular scale is necessary for material design. In this talk we introduce a multi-scale simulation approach which enables us to link the chemical structure of our materials to macroscopic device properties like I-V curves [1]. We first focus on understanding charge-transport in the BASF hole-transporting material DPBIC (Tris[(3-phenyl-1H-benzimidazol-1-yl-2(3H)-ylidene)-1,2-phenylene]Ir). Using our simulations we then investigate the role of DPBIC as co-host for a BASF carbene emitter. Device results for green OLEDs comprising such types of emission layers will be shown with CIE color coordinates (x=0.39, y=0.59) and EQEs exceeding 22% with driving voltages around 3V. In an optimized stack a device lifetime of LT95 > 15000h (1000 cd/m²) is reached fulfilling AMOLED display requirements. However, when aiming for deep blue emission, achieving high OLED stability becomes more challenging due to the combination of long emissive lifetimes with the high exciton energy. To solve this problem, BASF has developed the concept of hyper-phosphorescence based on combining phosphorescent and fluorescent emitters [2]. We will show that high efficiencies can be reached by charge-recombination on the phosphorescent emitter while at the same time realizing short emissive lifetimes by fast energy transfer to the fluorescent emitter, which allows for higher OLED stability in the deep blue. [1] P.Kordt et al, Adv. Funct. Mat. 25, 2015, [2] Talk by C. Lennartz, 249th ACS Meeting March 22-26, 2015