Theoretical predication for transition energies of thermally activated delayed fluorescence molecules

Thermally activated delayed fluorescence (TADF) emitters are primarily comprised of intramolecular charge-transfer (ICT) molecules with small energy difference between the lowest singlet and triplet excited states. They lend extremely favorable electroluminescent performance to organic light-emitting diodes (OLEDs). This paper summarizes relevant issues and research efforts in the theoretical prediction of singlet- and triplet-transition energies of ICT molecules via time-dependent density functional theory (TDDFT). The successful application of the descriptor-based optimal Hartree–Fock percentage method and the optimally tuned range-separated functional to many TADF systems represent an interesting approach to the exact prediction of the complex excited-state molecular dynamics within TDDFT.