General Approach To Compute Phosphorescent OLED Efficiency

Phosphorescent organic-light emitting diodes (PhOLEDs) are widely used in the display industry. In PhOLEDs, cyclometalated Ir(III) complexes are the most widespread triplet emitter dopants to attain red, e.g., Ir(piq)(3) (piq = 1-phenylisoquinoline), and green, e.g., Ir(ppy)(3) (ppy = 2-phenylpyridine) emission, whilst obtaining operative deep-blue emitters is still one of the major challenges. When designing new emitters two main characteristics, besides colours, should be targeted: high photostability and large photoluminescence efficiencies. To date, these are very often optimized experimentally in a trial-and-error manner. Instead, accurate predictive tools would be highly desirable. In this contribution, we present a general approach for computing the photo-luminescence lifetimes and efficiencies of Ir(III) complexes by considering all possible competing excited state deactivation processes, and importantly explicitly including the strongly temperature-dependent ones. This approach is based on state-of-the-art quantum chemical calculations with excited state decay rate formalism and the kinetic modelling, which is shown to be both efficient and reliable for a broad palette of Ir(III) complexes, i.e., from yellow/orange to deep-blue emitters.