Iridium Complex Ligand Design for Saturated Red and Blue OLED Emission

The patent modifies the chemical structure of phosphorescent emissive molecules by introducing specific ligand combinations (LA and LB) with defined coordination modes to the iridium center. This structural parameter change enables efficient red and blue emissions while maintaining the phosphorescent mechanism, thus improving emission efficiency without fundamentally changing the device structure or manufacturing process

The patent employs composite ligand systems where LA (a cyclometalating ligand) and LB (a picolinate-type ligand) work synergistically with the iridium metal center. This composite material approach creates a heteroleptic Ir(III) complex that achieves both saturated colors and high emission efficiency in red and blue regions, resolving the contradiction between material simplicity and performance

The patent precisely controls the coordination geometry and electronic structure of the Ir(III) complex by selecting specific LA and LB ligands with defined donor atoms and aromatic systems. This parameter optimization enables the complex to emit saturated red and blue light while maintaining compatibility with standard OLED fabrication processes, thus achieving high color saturation without complicating manufacturing

The patent introduces functional groups and aromatic systems at specific positions on the ligand frameworks (LA and LB) to locally enhance electron donation or acceptance properties. This local structural optimization allows precise tuning of emission wavelengths to achieve saturated red and blue colors while keeping the overall molecular structure synthesizable by conventional methods