Simulation of Low-Lying Singlet and Triplet Excited States of Multiple-Resonance-Type Thermally Activated Delayed Fluorescence Emitters by Delta Self-Consistent Field (ΔSCF) Method

The delta self-consistent field (Delta SCF) method was applied to the simulation of low-lying singlet and triplet excited states of multiple-resonance (MR)-type thermally activated delayed fluorescence (TADF) molecules, which form a promising group for organic light-emitting diode (OLED) emitters. A comparison with the experimental values of 13 emitters from the literature showed that Delta SCF gave fairly accurate S-1 and T-1 excitation energies (mean absolute errors (MAEs) of 0.092 and 0.055 eV, respectively) as well as quite accurate Delta E-ST (S-1-T-1 gap, MAE of 0.041 eV), which could not be calculated with sufficient accuracy by the conventional time-dependent density functional theory (TDDFT). Delta SCF also demonstrated its utility for the analysis of photophysical properties through a simulation of the reverse intersystem crossing (RISC) process of an MR-type emitter.

Automated summary

The Delta SCF method demonstrated high accuracy in simulating the excited states and photophysical properties of TADF molecules, particularly in calculating S-1 and T-1 excitation energies, as well as the S-1-T-1 gap.