Effect of first-order perturbative vibronic corrections on predicting transition rates in organic light-emitting diode systems

Abstract

To increase the efficiency of organic light-emitting diode systems, triplet excitons must be utilized. Phosphorescent emitters have been widely used, but their short lifetime and expensive heavy metals have led to the development of fluorescent emitters. To increase the efficiency of fluorescent phosphors, it is necessary to convert triplet excitons into singlet excitons, for which thermally activated delayed fluorescence, triplet-triplet annihilation, and hot exciton process have been studied. If the rates of radiative and nonradiative decay between different states can be calculated, the efficiency can be predicted. However, the calculation of transition rates does not agree well with experimental values. In this thesis, I calculated the transition rates of several systems using first-order perturbative vibronic corrections. Although my approach has some limitations, it is nonetheless expected to provide useful guidance for screening organic light-emitting diode systems.