Heterocyclic Compound for TADF OLED Efficiency

The patent modifies the molecular structure of TADF compounds by introducing specific heterocyclic groups (indoloindole, triazine) and linkers (phenylene, benzophenone) to change the energy level parameters. This structural modification reduces the energy gap between singlet and triplet states, enabling more effective triplet exciton utilization and improving fluorescent efficiency without losing the delayed fluorescence mechanism.

The patent employs composite molecular structures combining multiple functional groups (indoloindole donor group, triazine acceptor group, phenylene or benzophenone linkers) to create a TADF compound with optimized electronic properties. This composite approach allows simultaneous achievement of small singlet-triplet energy gap for triplet exciton utilization and high fluorescent efficiency.

The patent applies local quality by assigning specific functional roles to different parts of the molecular structure: the indoloindole group provides electron donation and influences emission color, the triazine group provides electron acceptance and affects energy levels, and the phenylene/benzophenone linkers control the electronic coupling. This localized functional assignment allows independent optimization of color purity and fluorescent efficiency.

The patent carefully adjusts molecular parameters including the type of linker (phenylene vs. benzophenone), substitution patterns, and auxiliary groups to fine-tune both the energy gap for efficient triplet utilization and the HOMO-LUMO gap for desired emission color. This parameter optimization resolves the contradiction between fluorescent efficiency and color purity.