Iridium Complex OLED Emitters for Saturated Color and Solution Processability
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Solution Overview
Problem
Current organic light-emitting diodes (OLEDs) face challenges in achieving saturated colors for full-color displays, particularly in producing vibrant red, green, and blue emissions, which are essential for industry standards, and there is a need for materials that can be efficiently processed in solution form to facilitate flexible and cost-effective device fabrication.
Innovation Solution
The development of specific compounds, represented by Formulas I and II, which are used in an organic layer of OLEDs, featuring mono-anionic bidentate and tridentate ligands, allowing for the formation of rings and coordination with iridium, enabling efficient phosphorescent emission and potentially improving color accuracy and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional OLED materials are used to achieve saturated colors, then color saturation may be improved, but solution processability and flexibility are compromised
Solution Approach 1:
The patent modifies the molecular structure of phosphorescent emitters by incorporating specific ligand systems (Formula I and Formula II with various substituent groups) to simultaneously achieve saturated color emission and solution processability. The structural parameters of the organic ligands are optimized to balance photophysical properties with solubility characteristics.
Solution Approach 2:
The invention uses composite ligand structures combining different functional groups (Y selected from O, S, and NRN; various aromatic and heteroaromatic substituents) to create emitters that integrate both high color saturation and solution processability within a single molecular framework.
2Power
If conventional phosphorescent emitters are used, then emission efficiency may be improved, but color accuracy for saturated red, green, and blue is compromised
Solution Approach 1:
The patent employs different ligand configurations (Formula I with mono-anionic bidentate ligands L1 and L2, or Formula II with tridentate ligand L3) tailored to specific emission colors. Each ligand system is locally optimized to achieve both high emission efficiency and accurate saturated color coordinates for red, green, or blue emission.
Solution Approach 2:
The invention systematically varies ligand parameters (different Y groups, aromatic substituents R, ring structures) to precisely tune the emission wavelength and color coordinates while maintaining high quantum efficiency, achieving both emission efficiency and color accuracy simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
These compounds enhance the ability of OLEDs to produce saturated colors and improve the efficiency of the emission process, potentially leading to better performance and cost-effectiveness in display technologies by facilitating solution-based processing and flexible device fabrication.
Implementation Method 1
One application for phosphorescent emissive molecules is a full color display
Data Source
AI summary
A compound of Formula I or Formula IIwhereinY is selected from the group consisting of O, S, and NRN; and(a) L1 and L2 are the same or different and are each a mono-anionic bidentate ligand; and R is selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; or(b) R joins with L1 of the Formulae I or II to form a ring B1 of formula B and formula C, respectively, and L2 is L3 and L3 is a tridentate ligand of formula Dwhereinring C, ring D, and ring E are each independently selected from the group consisting a 5-membered aryl, a 5-membered heteroaryl, a 6-membered aryl, and a 6-membered heteroaryl;X1 to X4 are independently selected from C or N, and no more than two of the X1 to X4 is N;Z1 to Z7 are independently selected from C or N; wherein one of Z1, Z4, and Z7 is an anionic donor, and the remaining two are neutral donors; wherein Z2 and Z3 are not both N, and Z5 and Z6 are not both N; and the dotted lines represent coordination to the iridium;wherein each RA to RE represents mono to the maximum allowable substitution, or no substitution; andeach RA to RE is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, wherein any two adjacent substituents RA to RE are optionally joined to form a fused ring.