Iridium Complex OLED Emitters for Color Saturation and Lifetime

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Solution Overview

Problem

Current organic light-emitting diode (OLED) technologies face challenges in achieving optimal color performance and device lifetime, particularly in producing saturated colors and maintaining efficiency in phosphorescent emitters.

Innovation Solution

Development of iridium complexes with multi-alkyl-substituted aza-DBF and 2-phenylpyridine ligands, which are used as emitters in OLEDs to enhance device performance by improving CIE color coordinates and extending the device's operational lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional phosphorescent emitters are used in OLEDs, then device fabrication is simpler, but color saturation and device lifetime are insufficient

Engineering Contradiction:
Improvedevice lifetimeVSAvoidemitter complex structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent modifies the ligand parameters of phosphorescent emitters by introducing multi-alkyl substitution patterns on aza-DBF ligands and optimizing the combination with 2-phenylpyridine ligands. These parameter changes in molecular structure improve device lifetime and color saturation while maintaining reasonable fabrication complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates composite phosphorescent emitter complexes combining iridium centers with specifically designed multi-alkyl substituted aza-DBF ligands and 2-phenylpyridine ligands. This composite material approach achieves superior device lifetime and color performance compared to conventional single-ligand complexes

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If standard iridium complexes are used, then synthesis is easier, but CIE color coordinates are not saturated

Engineering Contradiction:
ImproveCIE color coordinatesVSAvoidligand substitution pattern
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality modification by introducing alkyl substituents at specific positions on the aza-DBF ligand structure. This localized structural modification optimizes the electronic properties and HOMO/LUMO energy levels to achieve saturated CIE color coordinates, particularly for green emission

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent systematically varies parameters including the number and position of alkyl substituents, the type of heteroatom (O, S, or Se) in the aza-DBF ring, and the combination ratio with 2-phenylpyridine ligands to precisely tune the emission wavelength and achieve industry-standard saturated color coordinates

Inventive Principle:
Principle #35Parameter changes

3Reliability

If multi-alkyl substituted aza-DBF ligands are used, then color saturation and lifetime improve, but synthesis complexity increases

Engineering Contradiction:
Improvedevice lifetimeVSAvoidsynthesis process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs segmentation by designing the phosphorescent emitter as a modular complex with distinct ligand components (aza-DBF and 2-phenylpyridine) that can be synthesized and optimized independently before assembly. This modular approach manages synthesis complexity while achieving superior device lifetime through systematic ligand design

Inventive Principle:
Principle #1Segmentation

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

The use of these iridium complexes results in improved OLED performance by achieving better color rendition and extended device lifetime, with a blue shift in emission spectrum, making them suitable for high-performance OLED applications.

Implementation Method 1

One application for phosphorescent emissive molecules is a full color display

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentEP3045465B1Organic light emitting materials
Publication Date: 2019.01.30 UNIVERSAL DISPLAY CORP
  • EP3045465B1 patent drawingFigure 1
  • EP3045465B1 patent drawingFigure 2
  • EP3045465B1 patent drawingFigure 3

AI summary

Phosphorescent iridium complexes comprising multi-alkyl-substituted aza-DBF and 2-phenylpyridine ligands is disclosed. These complexes are useful as emitters for phosphorescent OLEDs.