Modeling Thermally Activated Delayed Fluorescence

Abstract

Thermally activated delayed fluorescence (TADF) has emerged as a key mechanism to enhance the efficiency of organic light-emitting devices by harvesting both singlet and triplet excitons. In this thesis, we present a detailed theoretical study of TADF using multi-level rate equation models, starting from the basic three-level system and extending to general multi-level singlet (S_m) and triplet (T_n) configurations. Analytical solutions for population dynamics are derived, revealing how excitons redistribute among higher singlet and triplet states over time. The results clearly show the origin of delayed fluorescence and provide insight into the interplay of radiative and non-radiative channels. This work presents a theoretical framework for predicting and optimizing TADF behavior in novel organic materials.