ИСТИНА

We propose a computational scheme for assessing the operational stability of potential OLED materials. Operational stability of four potential host molecules for blue PHOLEDs is studied based on the bond dissociation energies and exciton energies calculated theoretically using multireference CASSCF/XMCQDPT2 method. We focused on the degradation through breaking of exocyclic C–C and C–N bonds. The following processes that could lead to the operational degradation of OLED material are considered: the degradation of molecules in charged and excited states and degradation induced by exciton–polaron and exciton–exciton annihilation processes. The dissociation energies are calculated for different exocyclic bonds in the ground, excited, and charged states of these molecules. The least stable states and the most probable dissociation pathways are found. Based on our computations, a stability series is built for the four studied molecules, and the structural features that provide better stability with respect to unimolecular dissociation are determined. Thus, it is found that the carbazolyl group is detached much easier than the triphenylenyl group.