Computational Selection of Thermally Activated Delayed Fluorescence (TADF) Molecules with Promising Electrically Pumped Lasing Property

Thermally activated delayed fluorescence (TADF) materials are competitive candidates toward electrically pumped organic lasing, because of its ability to suppress triplet accumulations by reverse intersystem crossing (RISC), especially, the multiresonance TADF (MR-TADF) compounds featuring narrow-band emission and high photoluminescence quantum yields. The goal of this work is to theoretically screen out promising electrically pumped organic laser compounds over both MR-TADF and conventional TADF molecules. We calculate the photophysical parameters over 21 organic TADF molecules to determine if the electrically pumped lasing criteria can be met, i.e., no substantial absorption/annihilation processes caused by excitons and polarons near the S1 emission wavelength. The selection criteria include large oscillator strength of S1, large net emission cross-section, long S1 lifetime, and large reverse intersystem crossing rate. We are able to conclude that DABNA-2, m-Cz-BNCz, ADBNA-Me-Mes, and ADBNA-Me-Tips MR-TADF molecules are prospective candidates for electrically pumped lasing based on our theoretical protocol, and we believe this work would immediately benefit this field with better and more efficient molecular design of TADF gain materials.