| 초록 |
Organic light-emitting diodes (OLEDs) using thermally activated delayed fluorescence (TADF) has been attracted many researchers since they can utilize both singlet and triplet excitons, thus theoretically can reach 100% internal quantum efficiency. Developing blue-emitting TADF material is still challenging since they often suffer from low stability and broad emission spectrum. To circumvent these features, we propose a novel molecular design strategy; the strategy comprises i) compact molecular design, ii) strong donor and acceptor for highly efficient reverse intersystem crossing, iii) rigid structure for high chemical/electrochemical stability. Density functional theory (DFT) based calculations reveals spatially well separated highest occupied and lowest unoccupied molecular orbitals, resulting in small singlet-triplet splitting of ~10 meV. Electroluminescent devices with the TADF materials showed maximum external quantum efficiency of 1.7–6.5%. |
