Donor–Acceptor–Donor “Hot Exciton” Triads for High Reverse Intersystem Crossing in OLEDs

Hot exciton materials have the potential to improve quantum efficiency of organic light-emitting diodes (OLEDs) by promoting high reversed intersystem crossing (hRISC) between a high-lying triplet (Tn, n ≥ 2) and radiative singlet (Sm). In recent years, donor–acceptor–donor (D–A–D) molecular systems shown great promise in its ability enhance hRISC process under certain conditions. However, strategies find appropriate D–A–D combinations beyond trial-and-error are still elusive. This work exposes limited applicability current fragment-based design rules proposes high-throughput screening as optimal route candidates that fulfill energy criteria for hRISC. The strategy consists first establishing thresholds large triplet–triplet splitting small singlet–triplet gap, then filtering through rate comparison competitive pathways, finally confirming with spin-orbital coupling evaluation. Based on dataset 234 compounds, this protocol identifies 31 hRISC, 4 which reported literature. Remarkably, while most promising show prominent hybridized local charge transfer character, several do not condition, indicating different routes possible efficient OLED materials.