Iridium Complexes for Saturated OLED Emission

The patent applies parameter changes by systematically varying ligand parameters (substituents, backbone structures, coordination modes) on the iridium complex to achieve different emission colors. By changing parameters like the nature of ancillary ligands (Formula II and III) and tetradentate ligand structures (Formula I), the emission wavelength and color saturation are tuned across the visible spectrum, particularly achieving saturated red and blue emissions that were previously difficult to obtain.

The invention uses composite materials by combining iridium metal center with specifically designed organic ligands (tetradentate and monodentate) to create phosphorescent emissive complexes. These composite molecular structures integrate the heavy metal effect of iridium for high phosphorescence quantum yields with tailored organic ligands for color control, resulting in materials that simultaneously achieve high efficiency and saturated color emission.

The patent applies segmentation by dividing the complex ligand structure into modular components: a core tetradentate ligand framework (Formula I) with replaceable ancillary ligands (Formula II and III). This modular design allows independent optimization of each component's synthesis and facilitates precise control over the final complex's photophysical properties, achieving saturated colors through systematic component variation rather than synthesizing entirely new complex structures.

The invention applies local quality by introducing specific substituents at particular positions on the ligand structures to achieve desired emission colors. For example, specific substituents on the tetradentate ligand or ancillary ligands locally modify the electron density and HOMO-LUMO energy gaps, thereby controlling emission wavelength and color saturation without requiring complete redesign of the entire molecular structure.