Heteroacene OLED Material for High Efficiency and Long Lifetime

The patent modifies molecular parameters of the host material by introducing specific substituents (electron-withdrawing groups like CF3, F, Cl, and electron-donating groups like OMe, Me) to optimize HOMO/LUMO energy levels. This parameter optimization enables phosphorescent devices to operate at lower driving voltages (below 10V) while maintaining high luminous efficiency, thereby resolving the contradiction between energy efficiency and device reliability

The patent employs composite material systems combining specific host materials (compounds of formula 1 or 2) with phosphorescent dopants (Ir(III), Pt(II), or Os(III) complexes). This composite approach creates synergistic effects where the host material's optimized electronic structure facilitates efficient energy transfer to the phosphorescent dopant, achieving high luminous efficiency without requiring excessive driving voltage that would harm device lifetime

The patent optimizes molecular weight parameters to a specific range (500-2000 Da) and adjusts structural parameters by incorporating rigid aromatic cores with controlled substituents. This parameter optimization achieves the right balance: molecules are small enough for efficient vacuum deposition and low pixel defect density, yet large enough to provide thermal stability and morphological stability for reliable device operation

The patent applies local quality by introducing specific functional groups at particular positions on the molecular core. Electron-withdrawing groups are placed to stabilize the LUMO level for efficient electron transport, while electron-donating groups are positioned to stabilize the HOMO level. This localized structural modification allows the material to simultaneously achieve stability and deposition efficiency without requiring extreme molecular weight adjustments