Photophysical Properties of Thermally Activated Delayed Fluorescence Emitters From Optimally Tuned Range-Separated Functionals

Over the last years, the interests toward the molecules exhibiting thermally activated delayed fluorescence (TADF) have been increased. In this work, we propose novel optimally tuned range-separated hybrid density functionals (OT-RSHs) for reliable description of the photophysical properties such as absorption and emission energies as well as singlet-triplet gaps for the TADF emitters. Taking the BLYP, PBE, and TPSS density functional approximations as the exchange and correlation terms with various options for the short- and long-range exact-like exchange admixtures and the range-separation parameter, several OT-RSHs are proposed for predictions of the photophysical properties for a set of TADF emitters prone to be used in organic light emitting diodes (OLEDs). It is shown that the presented models not only have superior performance with respect to the standard counterparts but also outperform the earlier developed hybrids with both fixed and interelectronic distance-dependent exact-like exchange.