Study of Cyanobenzene Derivatives for Thermally Activated Delayed Fluorescence Emitters

Virtual Screening of Hole Transport, Electron Transport, and Host Layers for Effective OLED Design

“…For blue pixels, the fluorescent emitters are still the desired choice due to high stability. More recently, Adachi demonstrated that organic molecules could undergo thermally activated delayed fluorescence (TADF), where small energy gaps (Δ E ST ) between the lowest-lying singlet (S 1 ) and triplet (T 1 ) excited states of the emitter led to similar quantum efficiencies as that of phosphorescent OLEDs. , Various metal-free TADF materials, based on cyanobenzene, triazine, , and triazole, have been designed to widen the scope of this strategy. Importantly, the energy levels of frontier molecular orbitals (FMOs) can be aligned to tune the concentration of electrons and holes in the EML, which in turn determines the width and position of the recombination zone, resulting in a greatly improved device efficiency and lifetime. − …”

“…reported that the energy level alignment between the transporting layer and emissive host affects the charge carrier interface injection barriers and is therefore of great importance to achieving high external quantum efficiencies. While other factors such as the singlet–triplet gap of the emitter, − charge recombination, − and electron mobility affect OLED performance, , our goal in this work is to address the energy alignments of the three key OLED layers, which up to this point have not been designed as an integrated whole.…”